Rust support
This is the patch series (v6) to add support for Rust as a second
language to the Linux kernel.
If you are interested in following this effort, please join us in
the mailing list at:
[email protected]
and take a look at the project itself at:
https://github.com/Rust-for-Linux
As usual, special thanks go to ISRG (Internet Security Research
Group) and Google for their financial support on this endeavor.
Cheers,
Miguel
--
# Rust support
This cover letter explains the major changes and updates done since
the previous ones. For those, please see:
RFC: https://lore.kernel.org/lkml/[email protected]/
v1: https://lore.kernel.org/lkml/[email protected]/
v2: https://lore.kernel.org/lkml/[email protected]/
v3: https://lore.kernel.org/lkml/[email protected]/
v4: https://lore.kernel.org/lkml/[email protected]/
v5: https://lore.kernel.org/lkml/[email protected]/
## Infrastructure updates
There have been several improvements to the overall Rust support:
- The toolchain and `alloc` have been upgraded to Rust 1.60.0.
This version stabilized `feature(maybe_uninit_extra)` that we
are using.
- Support running documentation tests in-kernel, based on KUnit.
Rust documentation tests are typically examples of usage of any
item (e.g. function, struct, module...). They are very convenient
because they are just written alongside the documentation, e.g.:
/// Sums two numbers.
///
/// # Examples
///
/// ```
/// assert_eq!(mymod::f(10, 20), 30);
/// ```
pub fn f(a: i32, b: i32) -> i32 {
a + b
}
So far, we were compiling and running them in the host as any
other Rust documentation test. However, that meant we could not
run tests that used kernel APIs (though we were compile-testing
them, which was already useful to keep the documentation in sync
with the code).
Now, the documentation tests for the `kernel` crate are
transformed into a KUnit test suite during compilation and run
within the kernel at boot time, if enabled. This means now we can
run the tests that use kernel APIs.
They look like this (their name is generated by `rustdoc`, based
on the file and line):
[ 0.581961] TAP version 14
[ 0.582092] 1..1
[ 0.582267] # Subtest: rust_kernel_doctests
[ 0.582358] 1..70
[ 0.583626] ok 1 - rust_kernel_doctest_build_assert_rs_12_0
[ 0.584579] ok 2 - rust_kernel_doctest_build_assert_rs_55_0
[ 0.587357] ok 3 - rust_kernel_doctest_device_rs_361_0
[ 0.588037] ok 4 - rust_kernel_doctest_device_rs_386_0
...
[ 0.659249] ok 69 - rust_kernel_doctest_types_rs_445_0
[ 0.660451] ok 70 - rust_kernel_doctest_types_rs_509_0
[ 0.660680] # rust_kernel_doctests: pass:70 fail:0 skip:0 total:70
[ 0.660894] # Totals: pass:70 fail:0 skip:0 total:70
[ 0.661135] ok 1 - rust_kernel_doctests
There are other benefits from this, such as being able to remove
unneeded wrapper functions (that were used to avoid running
some tests) as well as ensuring test code would actually compile
within the kernel (e.g. `alloc` used different `cfg`s).
- Tests are now (and are enforced to be) Clippy-clean, like the rest
of the Rust kernel code (i.e. according to the same rules).
- Other cleanups, fixes and improvements.
## Abstractions and driver updates
Some of the improvements to the abstractions and example drivers are:
- The start of networking support (`net` module), with types like:
+ `Namespace` (based on `struct net`).
+ `SkBuff` (based on `struct sk_buff`).
+ `Ipv4Addr` (based on `struct in_addr`), and its v6 equivalent.
+ `SocketAddrV4` (based on `struct sockaddr_in`), and its v6
equivalent.
+ `TcpListener` and `TcpStream` (based on `struct socket`).
- The beginning of `async` support (`kasync` module).
Rust provides support for asynchronous programming in a way that
can be used in constrained environments, including the kernel.
For instance, this allows us to write asynchronous TCP socket code
within the kernel such as:
async fn echo_server(stream: TcpStream) -> Result {
let mut buf = [0u8; 1024];
loop {
let n = stream.read(&mut buf).await?;
if n == 0 {
return Ok(());
}
stream.write_all(&buf[..n]).await?;
}
}
This code looks very close to a synchronous version, yet it
supports being driven to completion "step by step" by an executor.
The `read()`/`write_all()` calls above, instead of blocking the
current thread, return a future which can be polled. The `.await`
points poll the future and, if the result is not ready, suspend
the state such that execution resumes there later on (the state
machine needed for this gets implemented by the compiler). This
allows an executor to drive multiple futures to completion
concurrently on the same thread.
An executor is not included yet, but `kasync` includes async
versions of `TcpListener` and `TcpStream` (based on the non-async
ones) which employ `SocketFuture` (which in turn uses a
`struct wait_queue_entry`).
- Support for network packet filters (`net::filter` module) and its
related `rust_netfilter.rs` sample.
- Added `smutex::Mutex`: a simple mutex that does not require
pinning, so that the ergonomics are much improved, though the
implementation is not as feature-rich as the C-based one.
- New `NoWaitLock`: one that never waits, that is, if it is owned
by another thread/CPU, then attempts to acquire it will fail
(instead of, for example, blocking the caller).
- Added `RawSpinLock` (backed by `raw_spinlock_t`), used when code
sections cannot sleep even in real-time variants of the kernel.
- Added `ARef`, an owned reference to an always-refcounted object,
meant to simplify how we define wrappers to types defined on the
C side of the source code.
- Other cleanups, fixes and improvements.
## Patch series status
The Rust support is still to be considered experimental. However,
support is good enough that kernel developers can start working on the
Rust abstractions for subsystems and write drivers and other modules.
The current series has just arrived in `linux-next`, as usual.
Similarly, the preview docs for this series can be seen at:
https://rust-for-linux.github.io/docs/kernel/
As usual, please see the following link for the live list of unstable
Rust features we are using:
https://github.com/Rust-for-Linux/linux/issues/2
## Conferences, meetings and liaisons
We would like to announce the Rust MC (microconference) in
the upcoming LPC 2022 (Linux Plumbers Conference):
https://lpc.events/event/16/contributions/1159/
The Rust MC intends to cover talks and discussions on both Rust for
Linux as well as other non-kernel Rust topics. The Call for Proposals
is open!
Furthermore, we would like to thank you the venues we were invited to:
- Rust Linz 2022
- Linux Foundation Live Mentorship Series
## Related news
`rustc_codegen_gcc` (the GCC backend for `rustc`) can now bootstrap
`rustc`! In addition, GCC 12.1 (just released) carries some of the
patches that were needed by the project in upstream `libgccjit`; and
the project is looking into getting distributed with `rustup`.
`gccrs` (the Rust frontend for GCC) has got a second full time
developer working on it, Arthur Cohen, as well as a lot of technical
progress too, such as a new testing project, slice generation support
and macro-related work.
## Acknowledgements
The signatures in the main commits correspond to the people that
wrote code that has ended up in them at the present time. For details
on contributions to code and discussions, please see our repository:
https://github.com/Rust-for-Linux/linux
However, we would like to give credit to everyone that has contributed
in one way or another to the Rust for Linux project. Since the
previous cover letter:
- Andy Shevchenko, Petr Mladek, Sergey Senozhatsky for their review
of the `vsprintf` patch.
- Arnaldo Carvalho de Melo and Andrii Nakryiko for their input on
`pahole` and BTF, Arnaldo for adding support `pahole` for `--lang`
and `--lang_exclude` (useful to skip Rust CUs) and Martin Reboredo
for reporting the `CONFIG_DEBUG_INFO_BTF` issue.
- Daniel Latypov, David Gow and Brendan Higgins for their input
on KUnit and their reviews on a prerequisite Rust patch on it.
- Kees Cook for reviewing the kallsyms prerequisite patches.
- Greg Kroah-Hartman for his suggestions on the `alloc` patch.
- Daniel Paoliello for his ongoing work on adding more `try_*`
methods to `Vec` in the standard library. Currently, we have some
similar methods in our custom `alloc` that we could drop once
equivalents arrive upstream. Also John Ericson for his reviews.
- bjorn3 for reviewing many PRs and the input around potential UB
in doctests.
- As usual, bjorn3 and Gary Guo for all the input on Rust compiler
details and suggestions.
- Adam Bratschi-Kaye for working on `seq_file` and `debugfs`
abstractions.
- Maciej Falkowski for continuing his work on the Samsung Exynos
TRNG driver and the required abstractions around it, such as
adding `delay`, `ktime` and `iopoll` abstractions, new methods
to `platform::Device` and run-time power management abstractions.
- Daniel Xu for working on adding a Rust allocator based on the
`kvmalloc` family of functions.
- Hongyu Li for working on Rust iterators as the equivalent of
`cpumask`'s `for_each_*_cpu`.
- Andreas Hindborg for adding support to `kernel::Pages` methods to
allow read/write of multiple pages.
- Sergio González Collado for working on adding `#[cold]` attributes
for error-related items and GitHub CI problem matchers.
- Sean Nash for updating the out-of-tree-module example due to a
change in the main repository.
- Michael Ellerman, Nicholas Piggin, Paul E. McKenney and Zhouyi
Zhou for debugging the `CONFIG_HIGH_RES_TIMERS=n` stall issue
in PowerPC that we triggered in our CI.
- Jonathan Corbet for writing an LWN article on the crates
discussion that took place in the Rust for Linux mailing list.
- Wei Liu for taking the time to answer questions from newcomers
in Zulip.
- Philip Li, Yujie Liu et al. for continuing their work on adding
Rust support to the Intel 0DAY/LKP kernel test robot.
- Philip Herron and Arthur Cohen (and his supporters Open Source
Security and Embecosm) et al. for their ongoing work on GCC Rust.
- Antoni Boucher (and his supporters) et al. for their ongoing
work on `rustc_codegen_gcc`.
- Mats Larsen, Marc Poulhiès et al. for their ongoing work on
improving Rust support in Compiler Explorer.
- Many folks that have reported issues, tested the project,
helped spread the word, joined discussions and contributed in
other ways!
Please see also the acknowledgements on the previous cover letters.
Boqun Feng (1):
kallsyms: avoid hardcoding the buffer size
Gary Guo (2):
rust: add `build_error` crate
vsprintf: add new `%pA` format specifier
Miguel Ojeda (16):
kallsyms: support "big" kernel symbols
kallsyms: increase maximum kernel symbol length to 512
kunit: take `kunit_assert` as `const`
rust: add C helpers
rust: add `compiler_builtins` crate
rust: import upstream `alloc` crate
rust: adapt `alloc` crate to the kernel
rust: add `macros` crate
rust: export generated symbols
scripts: add `rustdoc_test_{builder,gen}.py` scripts
scripts: add `generate_rust_analyzer.py` scripts
scripts: decode_stacktrace: demangle Rust symbols
docs: add Rust documentation
Kbuild: add Rust support
samples: add Rust examples
MAINTAINERS: Rust
Wedson Almeida Filho (4):
rust: add `kernel` crate's `sync` module
rust: add `kernel` crate
[RFC] drivers: gpio: PrimeCell PL061 in Rust
[RFC] drivers: android: Binder IPC in Rust
.gitignore | 5 +
.rustfmt.toml | 12 +
Documentation/doc-guide/kernel-doc.rst | 3 +
Documentation/index.rst | 1 +
Documentation/kbuild/kbuild.rst | 17 +
Documentation/kbuild/makefiles.rst | 50 +-
Documentation/process/changes.rst | 41 +
Documentation/rust/arch-support.rst | 34 +
Documentation/rust/coding-guidelines.rst | 214 ++
Documentation/rust/general-information.rst | 77 +
Documentation/rust/index.rst | 20 +
Documentation/rust/logo.svg | 357 ++
Documentation/rust/quick-start.rst | 230 ++
MAINTAINERS | 15 +
Makefile | 175 +-
arch/Kconfig | 6 +
arch/arm/Kconfig | 1 +
arch/arm64/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/riscv/Kconfig | 1 +
arch/riscv/Makefile | 5 +
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 14 +
drivers/android/Kconfig | 6 +
drivers/android/Makefile | 2 +
drivers/android/allocation.rs | 266 ++
drivers/android/context.rs | 80 +
drivers/android/defs.rs | 99 +
drivers/android/node.rs | 476 +++
drivers/android/process.rs | 960 +++++
drivers/android/range_alloc.rs | 189 +
drivers/android/rust_binder.rs | 111 +
drivers/android/thread.rs | 870 +++++
drivers/android/transaction.rs | 326 ++
drivers/gpio/Kconfig | 8 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio_pl061_rust.rs | 370 ++
include/kunit/test.h | 2 +-
include/linux/kallsyms.h | 2 +-
include/linux/spinlock.h | 25 +-
include/uapi/linux/android/binder.h | 28 +-
init/Kconfig | 45 +-
kernel/kallsyms.c | 26 +-
kernel/livepatch/core.c | 4 +-
lib/Kconfig.debug | 155 +
lib/kunit/test.c | 4 +-
lib/vsprintf.c | 13 +
rust/.gitignore | 10 +
rust/Makefile | 397 +++
rust/alloc/README.md | 32 +
rust/alloc/alloc.rs | 438 +++
rust/alloc/borrow.rs | 498 +++
rust/alloc/boxed.rs | 2007 +++++++++++
rust/alloc/collections/mod.rs | 156 +
rust/alloc/fmt.rs | 601 ++++
rust/alloc/lib.rs | 226 ++
rust/alloc/macros.rs | 127 +
rust/alloc/raw_vec.rs | 567 +++
rust/alloc/slice.rs | 1282 +++++++
rust/alloc/str.rs | 632 ++++
rust/alloc/string.rs | 2869 +++++++++++++++
rust/alloc/vec/drain.rs | 186 +
rust/alloc/vec/drain_filter.rs | 145 +
rust/alloc/vec/into_iter.rs | 356 ++
rust/alloc/vec/is_zero.rs | 106 +
rust/alloc/vec/mod.rs | 3362 ++++++++++++++++++
rust/alloc/vec/partial_eq.rs | 49 +
rust/alloc/vec/set_len_on_drop.rs | 30 +
rust/alloc/vec/spec_extend.rs | 174 +
rust/bindgen_parameters | 17 +
rust/build_error.rs | 29 +
rust/compiler_builtins.rs | 57 +
rust/exports.c | 20 +
rust/helpers.c | 639 ++++
rust/kernel/allocator.rs | 65 +
rust/kernel/amba.rs | 257 ++
rust/kernel/bindings.rs | 47 +
rust/kernel/bindings_helper.h | 46 +
rust/kernel/build_assert.rs | 82 +
rust/kernel/c_types.rs | 119 +
rust/kernel/chrdev.rs | 207 ++
rust/kernel/clk.rs | 79 +
rust/kernel/cred.rs | 46 +
rust/kernel/device.rs | 546 +++
rust/kernel/driver.rs | 442 +++
rust/kernel/error.rs | 565 +++
rust/kernel/file.rs | 860 +++++
rust/kernel/gpio.rs | 478 +++
rust/kernel/hwrng.rs | 242 ++
rust/kernel/io_buffer.rs | 153 +
rust/kernel/io_mem.rs | 275 ++
rust/kernel/iov_iter.rs | 81 +
rust/kernel/irq.rs | 409 +++
rust/kernel/kasync.rs | 6 +
rust/kernel/kasync/net.rs | 322 ++
rust/kernel/kunit.rs | 91 +
rust/kernel/lib.rs | 260 ++
rust/kernel/linked_list.rs | 247 ++
rust/kernel/miscdev.rs | 291 ++
rust/kernel/mm.rs | 149 +
rust/kernel/module_param.rs | 498 +++
rust/kernel/net.rs | 392 ++
rust/kernel/net/filter.rs | 447 +++
rust/kernel/of.rs | 63 +
rust/kernel/pages.rs | 144 +
rust/kernel/platform.rs | 223 ++
rust/kernel/power.rs | 118 +
rust/kernel/prelude.rs | 36 +
rust/kernel/print.rs | 405 +++
rust/kernel/random.rs | 42 +
rust/kernel/raw_list.rs | 361 ++
rust/kernel/rbtree.rs | 563 +++
rust/kernel/revocable.rs | 161 +
rust/kernel/security.rs | 38 +
rust/kernel/static_assert.rs | 38 +
rust/kernel/std_vendor.rs | 160 +
rust/kernel/str.rs | 597 ++++
rust/kernel/sync.rs | 161 +
rust/kernel/sync/arc.rs | 503 +++
rust/kernel/sync/condvar.rs | 138 +
rust/kernel/sync/guard.rs | 169 +
rust/kernel/sync/locked_by.rs | 111 +
rust/kernel/sync/mutex.rs | 153 +
rust/kernel/sync/nowait.rs | 188 +
rust/kernel/sync/revocable.rs | 250 ++
rust/kernel/sync/rwsem.rs | 197 +
rust/kernel/sync/seqlock.rs | 202 ++
rust/kernel/sync/smutex.rs | 295 ++
rust/kernel/sync/spinlock.rs | 360 ++
rust/kernel/sysctl.rs | 199 ++
rust/kernel/task.rs | 175 +
rust/kernel/types.rs | 679 ++++
rust/kernel/user_ptr.rs | 175 +
rust/macros/helpers.rs | 79 +
rust/macros/lib.rs | 94 +
rust/macros/module.rs | 631 ++++
samples/Kconfig | 2 +
samples/Makefile | 1 +
samples/rust/Kconfig | 140 +
samples/rust/Makefile | 16 +
samples/rust/hostprogs/.gitignore | 3 +
samples/rust/hostprogs/Makefile | 5 +
samples/rust/hostprogs/a.rs | 7 +
samples/rust/hostprogs/b.rs | 5 +
samples/rust/hostprogs/single.rs | 12 +
samples/rust/rust_chrdev.rs | 50 +
samples/rust/rust_minimal.rs | 35 +
samples/rust/rust_miscdev.rs | 143 +
samples/rust/rust_module_parameters.rs | 69 +
samples/rust/rust_netfilter.rs | 54 +
samples/rust/rust_platform.rs | 22 +
samples/rust/rust_print.rs | 54 +
samples/rust/rust_random.rs | 60 +
samples/rust/rust_semaphore.rs | 171 +
samples/rust/rust_semaphore_c.c | 212 ++
samples/rust/rust_stack_probing.rs | 36 +
samples/rust/rust_sync.rs | 93 +
scripts/.gitignore | 1 +
scripts/Kconfig.include | 6 +-
scripts/Makefile | 3 +
scripts/Makefile.build | 60 +
scripts/Makefile.debug | 10 +
scripts/Makefile.host | 34 +-
scripts/Makefile.lib | 12 +
scripts/Makefile.modfinal | 8 +-
scripts/cc-version.sh | 12 +-
scripts/decode_stacktrace.sh | 14 +
scripts/generate_rust_analyzer.py | 134 +
scripts/generate_rust_target.rs | 227 ++
scripts/is_rust_module.sh | 13 +
scripts/kallsyms.c | 47 +-
scripts/kconfig/confdata.c | 75 +
scripts/min-tool-version.sh | 6 +
scripts/rust-is-available-bindgen-libclang.h | 2 +
scripts/rust-is-available.sh | 158 +
scripts/rustdoc_test_builder.py | 59 +
scripts/rustdoc_test_gen.py | 164 +
tools/include/linux/kallsyms.h | 2 +-
tools/lib/perf/include/perf/event.h | 2 +-
tools/lib/symbol/kallsyms.h | 2 +-
180 files changed, 37945 insertions(+), 67 deletions(-)
create mode 100644 .rustfmt.toml
create mode 100644 Documentation/rust/arch-support.rst
create mode 100644 Documentation/rust/coding-guidelines.rst
create mode 100644 Documentation/rust/general-information.rst
create mode 100644 Documentation/rust/index.rst
create mode 100644 Documentation/rust/logo.svg
create mode 100644 Documentation/rust/quick-start.rst
create mode 100644 drivers/android/allocation.rs
create mode 100644 drivers/android/context.rs
create mode 100644 drivers/android/defs.rs
create mode 100644 drivers/android/node.rs
create mode 100644 drivers/android/process.rs
create mode 100644 drivers/android/range_alloc.rs
create mode 100644 drivers/android/rust_binder.rs
create mode 100644 drivers/android/thread.rs
create mode 100644 drivers/android/transaction.rs
create mode 100644 drivers/gpio/gpio_pl061_rust.rs
create mode 100644 rust/.gitignore
create mode 100644 rust/Makefile
create mode 100644 rust/alloc/README.md
create mode 100644 rust/alloc/alloc.rs
create mode 100644 rust/alloc/borrow.rs
create mode 100644 rust/alloc/boxed.rs
create mode 100644 rust/alloc/collections/mod.rs
create mode 100644 rust/alloc/fmt.rs
create mode 100644 rust/alloc/lib.rs
create mode 100644 rust/alloc/macros.rs
create mode 100644 rust/alloc/raw_vec.rs
create mode 100644 rust/alloc/slice.rs
create mode 100644 rust/alloc/str.rs
create mode 100644 rust/alloc/string.rs
create mode 100644 rust/alloc/vec/drain.rs
create mode 100644 rust/alloc/vec/drain_filter.rs
create mode 100644 rust/alloc/vec/into_iter.rs
create mode 100644 rust/alloc/vec/is_zero.rs
create mode 100644 rust/alloc/vec/mod.rs
create mode 100644 rust/alloc/vec/partial_eq.rs
create mode 100644 rust/alloc/vec/set_len_on_drop.rs
create mode 100644 rust/alloc/vec/spec_extend.rs
create mode 100644 rust/bindgen_parameters
create mode 100644 rust/build_error.rs
create mode 100644 rust/compiler_builtins.rs
create mode 100644 rust/exports.c
create mode 100644 rust/helpers.c
create mode 100644 rust/kernel/allocator.rs
create mode 100644 rust/kernel/amba.rs
create mode 100644 rust/kernel/bindings.rs
create mode 100644 rust/kernel/bindings_helper.h
create mode 100644 rust/kernel/build_assert.rs
create mode 100644 rust/kernel/c_types.rs
create mode 100644 rust/kernel/chrdev.rs
create mode 100644 rust/kernel/clk.rs
create mode 100644 rust/kernel/cred.rs
create mode 100644 rust/kernel/device.rs
create mode 100644 rust/kernel/driver.rs
create mode 100644 rust/kernel/error.rs
create mode 100644 rust/kernel/file.rs
create mode 100644 rust/kernel/gpio.rs
create mode 100644 rust/kernel/hwrng.rs
create mode 100644 rust/kernel/io_buffer.rs
create mode 100644 rust/kernel/io_mem.rs
create mode 100644 rust/kernel/iov_iter.rs
create mode 100644 rust/kernel/irq.rs
create mode 100644 rust/kernel/kasync.rs
create mode 100644 rust/kernel/kasync/net.rs
create mode 100644 rust/kernel/kunit.rs
create mode 100644 rust/kernel/lib.rs
create mode 100644 rust/kernel/linked_list.rs
create mode 100644 rust/kernel/miscdev.rs
create mode 100644 rust/kernel/mm.rs
create mode 100644 rust/kernel/module_param.rs
create mode 100644 rust/kernel/net.rs
create mode 100644 rust/kernel/net/filter.rs
create mode 100644 rust/kernel/of.rs
create mode 100644 rust/kernel/pages.rs
create mode 100644 rust/kernel/platform.rs
create mode 100644 rust/kernel/power.rs
create mode 100644 rust/kernel/prelude.rs
create mode 100644 rust/kernel/print.rs
create mode 100644 rust/kernel/random.rs
create mode 100644 rust/kernel/raw_list.rs
create mode 100644 rust/kernel/rbtree.rs
create mode 100644 rust/kernel/revocable.rs
create mode 100644 rust/kernel/security.rs
create mode 100644 rust/kernel/static_assert.rs
create mode 100644 rust/kernel/std_vendor.rs
create mode 100644 rust/kernel/str.rs
create mode 100644 rust/kernel/sync.rs
create mode 100644 rust/kernel/sync/arc.rs
create mode 100644 rust/kernel/sync/condvar.rs
create mode 100644 rust/kernel/sync/guard.rs
create mode 100644 rust/kernel/sync/locked_by.rs
create mode 100644 rust/kernel/sync/mutex.rs
create mode 100644 rust/kernel/sync/nowait.rs
create mode 100644 rust/kernel/sync/revocable.rs
create mode 100644 rust/kernel/sync/rwsem.rs
create mode 100644 rust/kernel/sync/seqlock.rs
create mode 100644 rust/kernel/sync/smutex.rs
create mode 100644 rust/kernel/sync/spinlock.rs
create mode 100644 rust/kernel/sysctl.rs
create mode 100644 rust/kernel/task.rs
create mode 100644 rust/kernel/types.rs
create mode 100644 rust/kernel/user_ptr.rs
create mode 100644 rust/macros/helpers.rs
create mode 100644 rust/macros/lib.rs
create mode 100644 rust/macros/module.rs
create mode 100644 samples/rust/Kconfig
create mode 100644 samples/rust/Makefile
create mode 100644 samples/rust/hostprogs/.gitignore
create mode 100644 samples/rust/hostprogs/Makefile
create mode 100644 samples/rust/hostprogs/a.rs
create mode 100644 samples/rust/hostprogs/b.rs
create mode 100644 samples/rust/hostprogs/single.rs
create mode 100644 samples/rust/rust_chrdev.rs
create mode 100644 samples/rust/rust_minimal.rs
create mode 100644 samples/rust/rust_miscdev.rs
create mode 100644 samples/rust/rust_module_parameters.rs
create mode 100644 samples/rust/rust_netfilter.rs
create mode 100644 samples/rust/rust_platform.rs
create mode 100644 samples/rust/rust_print.rs
create mode 100644 samples/rust/rust_random.rs
create mode 100644 samples/rust/rust_semaphore.rs
create mode 100644 samples/rust/rust_semaphore_c.c
create mode 100644 samples/rust/rust_stack_probing.rs
create mode 100644 samples/rust/rust_sync.rs
create mode 100755 scripts/generate_rust_analyzer.py
create mode 100644 scripts/generate_rust_target.rs
create mode 100755 scripts/is_rust_module.sh
create mode 100644 scripts/rust-is-available-bindgen-libclang.h
create mode 100755 scripts/rust-is-available.sh
create mode 100755 scripts/rustdoc_test_builder.py
create mode 100755 scripts/rustdoc_test_gen.py
base-commit: 672c0c5173427e6b3e2a9bbb7be51ceeec78093a
--
2.35.3
All symbols are reexported reusing the `EXPORT_SYMBOL_GPL` macro
from C. The lists of symbols are generated on the fly.
There are three main sets of symbols to distinguish:
- The ones from the `core` and `alloc` crates (from the Rust
standard library). The code is licensed as Apache/MIT.
- The ones from our abstractions in the `kernel` crate.
- The helpers (already exported since they are not generated).
We export everything as GPL. This ensures we do not mistakenly
expose GPL kernel symbols/features as non-GPL, even indirectly.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
rust/exports.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
create mode 100644 rust/exports.c
diff --git a/rust/exports.c b/rust/exports.c
new file mode 100644
index 000000000000..fe3dcfdd6fbf
--- /dev/null
+++ b/rust/exports.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A hack to export Rust symbols for loadable modules without having to redo
+ * the entire `include/linux/export.h` logic in Rust.
+ *
+ * This requires the Rust's new/future `v0` mangling scheme because the default
+ * one ("legacy") uses invalid characters for C identifiers (thus we cannot use
+ * the `EXPORT_SYMBOL_*` macros).
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ */
+
+#include <linux/module.h>
+
+#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym);
+
+#include "exports_core_generated.h"
+#include "exports_alloc_generated.h"
+#include "exports_kernel_generated.h"
--
2.35.3
From: Gary Guo <[email protected]>
The `build_error` crate provides the `build_error` function which
is then used to provide the `build_error!` and the `build_assert!`
macros.
`build_assert!` is intended to be used when `static_assert!` cannot
be used, e.g. when the condition refers to generic parameters or
parameters of an inline function.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
rust/build_error.rs | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100644 rust/build_error.rs
diff --git a/rust/build_error.rs b/rust/build_error.rs
new file mode 100644
index 000000000000..34e589149d3e
--- /dev/null
+++ b/rust/build_error.rs
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Build-time error.
+//!
+//! This crate provides a function `build_error`, which will panic in
+//! compile-time if executed in const context, and will cause a build error
+//! if not executed at compile time and the optimizer does not optimise away the
+//! call.
+//!
+//! It is used by `build_assert!` in the kernel crate, allowing checking of
+//! conditions that could be checked statically, but could not be enforced in
+//! Rust yet (e.g. perform some checks in const functions, but those
+//! functions could still be called in the runtime).
+
+#![no_std]
+
+/// Panics if executed in const context, or triggers a build error if not.
+#[inline(never)]
+#[cold]
+#[no_mangle]
+#[track_caller]
+pub const fn build_error(msg: &'static str) -> ! {
+ panic!("{}", msg);
+}
+
+#[cfg(CONFIG_RUST_BUILD_ASSERT_WARN)]
+#[link_section = ".gnu.warning.build_error"]
+#[used]
+static BUILD_ERROR_WARNING: [u8; 45] = *b"call to build_error present after compilation";
--
2.35.3
This source file contains forwarders to C macros and inlined
functions.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Geoffrey Thomas <[email protected]>
Signed-off-by: Geoffrey Thomas <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Sven Van Asbroeck <[email protected]>
Signed-off-by: Sven Van Asbroeck <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Boqun Feng <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Co-developed-by: Maciej Falkowski <[email protected]>
Signed-off-by: Maciej Falkowski <[email protected]>
Co-developed-by: Wei Liu <[email protected]>
Signed-off-by: Wei Liu <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
rust/helpers.c | 639 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 639 insertions(+)
create mode 100644 rust/helpers.c
diff --git a/rust/helpers.c b/rust/helpers.c
new file mode 100644
index 000000000000..440132e04ccc
--- /dev/null
+++ b/rust/helpers.c
@@ -0,0 +1,639 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
+ * cannot be called either. This file explicitly creates functions ("helpers")
+ * that wrap those so that they can be called from Rust.
+ *
+ * Even though Rust kernel modules should never use directly the bindings, some
+ * of these helpers need to be exported because Rust generics and inlined
+ * functions may not get their code generated in the crate where they are
+ * defined. Other helpers, called from non-inline functions, may not be
+ * exported, in principle. However, in general, the Rust compiler does not
+ * guarantee codegen will be performed for a non-inline function either.
+ * Therefore, this file exports all the helpers. In the future, this may be
+ * revisited to reduce the number of exports after the compiler is informed
+ * about the places codegen is required.
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ */
+
+#include <linux/bug.h>
+#include <linux/build_bug.h>
+#include <linux/clk.h>
+#include <linux/uaccess.h>
+#include <linux/sched/signal.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/uio.h>
+#include <linux/errname.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/security.h>
+#include <asm/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/amba/bus.h>
+#include <linux/of_device.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+
+__noreturn void rust_helper_BUG(void)
+{
+ BUG();
+}
+EXPORT_SYMBOL_GPL(rust_helper_BUG);
+
+void rust_helper_clk_disable_unprepare(struct clk *clk)
+{
+ return clk_disable_unprepare(clk);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clk_disable_unprepare);
+
+int rust_helper_clk_prepare_enable(struct clk *clk)
+{
+ return clk_prepare_enable(clk);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clk_prepare_enable);
+
+unsigned long rust_helper_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ return copy_from_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_user);
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ return copy_to_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_user);
+
+unsigned long rust_helper_clear_user(void __user *to, unsigned long n)
+{
+ return clear_user(to, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clear_user);
+
+void __iomem *rust_helper_ioremap(resource_size_t offset, unsigned long size)
+{
+ return ioremap(offset, size);
+}
+EXPORT_SYMBOL_GPL(rust_helper_ioremap);
+
+u8 rust_helper_readb(const volatile void __iomem *addr)
+{
+ return readb(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readb);
+
+u16 rust_helper_readw(const volatile void __iomem *addr)
+{
+ return readw(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readw);
+
+u32 rust_helper_readl(const volatile void __iomem *addr)
+{
+ return readl(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readl);
+
+#ifdef CONFIG_64BIT
+u64 rust_helper_readq(const volatile void __iomem *addr)
+{
+ return readq(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readq);
+#endif
+
+void rust_helper_writeb(u8 value, volatile void __iomem *addr)
+{
+ writeb(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeb);
+
+void rust_helper_writew(u16 value, volatile void __iomem *addr)
+{
+ writew(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writew);
+
+void rust_helper_writel(u32 value, volatile void __iomem *addr)
+{
+ writel(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writel);
+
+#ifdef CONFIG_64BIT
+void rust_helper_writeq(u64 value, volatile void __iomem *addr)
+{
+ writeq(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeq);
+#endif
+
+u8 rust_helper_readb_relaxed(const volatile void __iomem *addr)
+{
+ return readb_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readb_relaxed);
+
+u16 rust_helper_readw_relaxed(const volatile void __iomem *addr)
+{
+ return readw_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readw_relaxed);
+
+u32 rust_helper_readl_relaxed(const volatile void __iomem *addr)
+{
+ return readl_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readl_relaxed);
+
+#ifdef CONFIG_64BIT
+u64 rust_helper_readq_relaxed(const volatile void __iomem *addr)
+{
+ return readq_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readq_relaxed);
+#endif
+
+void rust_helper_writeb_relaxed(u8 value, volatile void __iomem *addr)
+{
+ writeb_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeb_relaxed);
+
+void rust_helper_writew_relaxed(u16 value, volatile void __iomem *addr)
+{
+ writew_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writew_relaxed);
+
+void rust_helper_writel_relaxed(u32 value, volatile void __iomem *addr)
+{
+ writel_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writel_relaxed);
+
+#ifdef CONFIG_64BIT
+void rust_helper_writeq_relaxed(u64 value, volatile void __iomem *addr)
+{
+ writeq_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeq_relaxed);
+#endif
+
+void rust_helper_memcpy_fromio(void *to, const volatile void __iomem *from, long count)
+{
+ memcpy_fromio(to, from, count);
+}
+EXPORT_SYMBOL_GPL(rust_helper_memcpy_fromio);
+
+void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+ __spin_lock_init(lock, name, key);
+#else
+ spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+ spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+ spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
+
+unsigned long rust_helper_spin_lock_irqsave(spinlock_t *lock)
+{
+ unsigned long flags;
+ spin_lock_irqsave(lock, flags);
+ return flags;
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock_irqsave);
+
+void rust_helper_spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
+{
+ spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock_irqrestore);
+
+void rust_helper__raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+ struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+ _raw_spin_lock_init(lock, name, key);
+#else
+ raw_spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper__raw_spin_lock_init);
+
+void rust_helper_raw_spin_lock(raw_spinlock_t *lock)
+{
+ raw_spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_lock);
+
+void rust_helper_raw_spin_unlock(raw_spinlock_t *lock)
+{
+ raw_spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_unlock);
+
+unsigned long rust_helper_raw_spin_lock_irqsave(raw_spinlock_t *lock)
+{
+ unsigned long flags;
+ raw_spin_lock_irqsave(lock, flags);
+ return flags;
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_lock_irqsave);
+
+void rust_helper_raw_spin_unlock_irqrestore(raw_spinlock_t *lock,
+ unsigned long flags)
+{
+ raw_spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_unlock_irqrestore);
+
+void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
+{
+ init_wait(wq_entry);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_wait);
+
+void rust_helper_init_waitqueue_func_entry(struct wait_queue_entry *wq_entry,
+ wait_queue_func_t func)
+{
+ init_waitqueue_func_entry(wq_entry, func);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_waitqueue_func_entry);
+
+int rust_helper_signal_pending(struct task_struct *t)
+{
+ return signal_pending(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
+
+struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+ return alloc_pages(gfp_mask, order);
+}
+EXPORT_SYMBOL_GPL(rust_helper_alloc_pages);
+
+void *rust_helper_kmap(struct page *page)
+{
+ return kmap(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kmap);
+
+void rust_helper_kunmap(struct page *page)
+{
+ return kunmap(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kunmap);
+
+int rust_helper_cond_resched(void)
+{
+ return cond_resched();
+}
+EXPORT_SYMBOL_GPL(rust_helper_cond_resched);
+
+size_t rust_helper_copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
+{
+ return copy_from_iter(addr, bytes, i);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_iter);
+
+size_t rust_helper_copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
+{
+ return copy_to_iter(addr, bytes, i);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_iter);
+
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+ return IS_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+ return PTR_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
+
+const char *rust_helper_errname(int err)
+{
+ return errname(err);
+}
+EXPORT_SYMBOL_GPL(rust_helper_errname);
+
+void rust_helper_mutex_lock(struct mutex *lock)
+{
+ mutex_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
+
+void rust_helper_amba_set_drvdata(struct amba_device *dev, void *data)
+{
+ amba_set_drvdata(dev, data);
+}
+EXPORT_SYMBOL_GPL(rust_helper_amba_set_drvdata);
+
+void *rust_helper_amba_get_drvdata(struct amba_device *dev)
+{
+ return amba_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_amba_get_drvdata);
+
+void *
+rust_helper_platform_get_drvdata(const struct platform_device *pdev)
+{
+ return platform_get_drvdata(pdev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_platform_get_drvdata);
+
+void
+rust_helper_platform_set_drvdata(struct platform_device *pdev,
+ void *data)
+{
+ return platform_set_drvdata(pdev, data);
+}
+EXPORT_SYMBOL_GPL(rust_helper_platform_set_drvdata);
+
+refcount_t rust_helper_REFCOUNT_INIT(int n)
+{
+ return (refcount_t)REFCOUNT_INIT(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
+
+void rust_helper_refcount_inc(refcount_t *r)
+{
+ refcount_inc(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
+
+bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+ return refcount_dec_and_test(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
+
+void rust_helper_rb_link_node(struct rb_node *node, struct rb_node *parent,
+ struct rb_node **rb_link)
+{
+ rb_link_node(node, parent, rb_link);
+}
+EXPORT_SYMBOL_GPL(rust_helper_rb_link_node);
+
+struct task_struct *rust_helper_get_current(void)
+{
+ return current;
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_current);
+
+void rust_helper_get_task_struct(struct task_struct * t)
+{
+ get_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
+
+void rust_helper_put_task_struct(struct task_struct * t)
+{
+ put_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
+
+int rust_helper_security_binder_set_context_mgr(const struct cred *mgr)
+{
+ return security_binder_set_context_mgr(mgr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_set_context_mgr);
+
+int rust_helper_security_binder_transaction(const struct cred *from,
+ const struct cred *to)
+{
+ return security_binder_transaction(from, to);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transaction);
+
+int rust_helper_security_binder_transfer_binder(const struct cred *from,
+ const struct cred *to)
+{
+ return security_binder_transfer_binder(from, to);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transfer_binder);
+
+int rust_helper_security_binder_transfer_file(const struct cred *from,
+ const struct cred *to,
+ struct file *file)
+{
+ return security_binder_transfer_file(from, to, file);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transfer_file);
+
+struct file *rust_helper_get_file(struct file *f)
+{
+ return get_file(f);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_file);
+
+void rust_helper_rcu_read_lock(void)
+{
+ rcu_read_lock();
+}
+EXPORT_SYMBOL_GPL(rust_helper_rcu_read_lock);
+
+void rust_helper_rcu_read_unlock(void)
+{
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(rust_helper_rcu_read_unlock);
+
+void rust_helper_synchronize_rcu(void)
+{
+ synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(rust_helper_synchronize_rcu);
+
+void *rust_helper_dev_get_drvdata(struct device *dev)
+{
+ return dev_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_get_drvdata);
+
+const char *rust_helper_dev_name(const struct device *dev)
+{
+ return dev_name(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_name);
+
+void rust_helper___seqcount_init(seqcount_t *s, const char *name,
+ struct lock_class_key *key)
+{
+ __seqcount_init(s, name, key);
+}
+EXPORT_SYMBOL_GPL(rust_helper___seqcount_init);
+
+unsigned rust_helper_read_seqcount_begin(seqcount_t *s)
+{
+ return read_seqcount_begin(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_read_seqcount_begin);
+
+int rust_helper_read_seqcount_retry(seqcount_t *s, unsigned start)
+{
+ return read_seqcount_retry(s, start);
+}
+EXPORT_SYMBOL_GPL(rust_helper_read_seqcount_retry);
+
+void rust_helper_write_seqcount_begin(seqcount_t *s)
+{
+ do_write_seqcount_begin(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_write_seqcount_begin);
+
+void rust_helper_write_seqcount_end(seqcount_t *s)
+{
+ do_write_seqcount_end(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_write_seqcount_end);
+
+void rust_helper_irq_set_handler_locked(struct irq_data *data,
+ irq_flow_handler_t handler)
+{
+ irq_set_handler_locked(data, handler);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_set_handler_locked);
+
+void *rust_helper_irq_data_get_irq_chip_data(struct irq_data *d)
+{
+ return irq_data_get_irq_chip_data(d);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_data_get_irq_chip_data);
+
+struct irq_chip *rust_helper_irq_desc_get_chip(struct irq_desc *desc)
+{
+ return irq_desc_get_chip(desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_desc_get_chip);
+
+void *rust_helper_irq_desc_get_handler_data(struct irq_desc *desc)
+{
+ return irq_desc_get_handler_data(desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_desc_get_handler_data);
+
+void rust_helper_chained_irq_enter(struct irq_chip *chip,
+ struct irq_desc *desc)
+{
+ chained_irq_enter(chip, desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_chained_irq_enter);
+
+void rust_helper_chained_irq_exit(struct irq_chip *chip,
+ struct irq_desc *desc)
+{
+ chained_irq_exit(chip, desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_chained_irq_exit);
+
+const struct cred *rust_helper_get_cred(const struct cred *cred)
+{
+ return get_cred(cred);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_cred);
+
+void rust_helper_put_cred(const struct cred *cred) {
+ put_cred(cred);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_cred);
+
+const struct of_device_id *rust_helper_of_match_device(
+ const struct of_device_id *matches, const struct device *dev)
+{
+ return of_match_device(matches, dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_of_match_device);
+
+void rust_helper_init_completion(struct completion *c)
+{
+ init_completion(c);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_completion);
+
+struct sk_buff *rust_helper_skb_get(struct sk_buff *skb)
+{
+ return skb_get(skb);
+}
+EXPORT_SYMBOL_GPL(rust_helper_skb_get);
+
+unsigned int rust_helper_skb_headlen(const struct sk_buff *skb)
+{
+ return skb_headlen(skb);
+}
+EXPORT_SYMBOL_GPL(rust_helper_skb_headlen);
+
+void rust_helper_dev_hold(struct net_device *dev)
+{
+ return dev_hold(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_hold);
+
+void rust_helper_dev_put(struct net_device *dev)
+{
+ return dev_put(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_put);
+
+struct net *rust_helper_get_net(struct net *net)
+{
+ return get_net(net);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_net);
+
+void rust_helper_put_net(struct net *net)
+{
+ return put_net(net);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_net);
+
+unsigned int rust_helper_NF_QUEUE_NR(unsigned int n)
+{
+ return NF_QUEUE_NR(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_NF_QUEUE_NR);
+
+/*
+ * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
+ * as the Rust `usize` type, so we can use it in contexts where Rust
+ * expects a `usize` like slice (array) indices. `usize` is defined to be
+ * the same as C's `uintptr_t` type (can hold any pointer) but not
+ * necessarily the same as `size_t` (can hold the size of any single
+ * object). Most modern platforms use the same concrete integer type for
+ * both of them, but in case we find ourselves on a platform where
+ * that's not true, fail early instead of risking ABI or
+ * integer-overflow issues.
+ *
+ * If your platform fails this assertion, it means that you are in
+ * danger of integer-overflow bugs (even if you attempt to remove
+ * `--size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
+ * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
+ */
+static_assert(
+ sizeof(size_t) == sizeof(uintptr_t) &&
+ __alignof__(size_t) == __alignof__(uintptr_t),
+ "Rust code expects C `size_t` to match Rust `usize`"
+);
--
2.35.3
A set of Rust modules that showcase how Rust modules look like
and how to use the abstracted kernel features, as well as
an example of a Rust host program with several modules.
These samples also double as tests in the CI.
The semaphore sample comes with a C version for comparison.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Finn Behrens <[email protected]>
Signed-off-by: Finn Behrens <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Co-developed-by: Sven Van Asbroeck <[email protected]>
Signed-off-by: Sven Van Asbroeck <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Boris-Chengbiao Zhou <[email protected]>
Signed-off-by: Boris-Chengbiao Zhou <[email protected]>
Co-developed-by: Ayaan Zaidi <[email protected]>
Signed-off-by: Ayaan Zaidi <[email protected]>
Co-developed-by: Milan Landaverde <[email protected]>
Signed-off-by: Milan Landaverde <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
samples/Kconfig | 2 +
samples/Makefile | 1 +
samples/rust/Kconfig | 140 ++++++++++++++++
samples/rust/Makefile | 16 ++
samples/rust/hostprogs/.gitignore | 3 +
samples/rust/hostprogs/Makefile | 5 +
samples/rust/hostprogs/a.rs | 7 +
samples/rust/hostprogs/b.rs | 5 +
samples/rust/hostprogs/single.rs | 12 ++
samples/rust/rust_chrdev.rs | 50 ++++++
samples/rust/rust_minimal.rs | 35 ++++
samples/rust/rust_miscdev.rs | 143 +++++++++++++++++
samples/rust/rust_module_parameters.rs | 69 ++++++++
samples/rust/rust_netfilter.rs | 54 +++++++
samples/rust/rust_platform.rs | 22 +++
samples/rust/rust_print.rs | 54 +++++++
samples/rust/rust_random.rs | 60 +++++++
samples/rust/rust_semaphore.rs | 171 ++++++++++++++++++++
samples/rust/rust_semaphore_c.c | 212 +++++++++++++++++++++++++
samples/rust/rust_stack_probing.rs | 36 +++++
samples/rust/rust_sync.rs | 93 +++++++++++
21 files changed, 1190 insertions(+)
create mode 100644 samples/rust/Kconfig
create mode 100644 samples/rust/Makefile
create mode 100644 samples/rust/hostprogs/.gitignore
create mode 100644 samples/rust/hostprogs/Makefile
create mode 100644 samples/rust/hostprogs/a.rs
create mode 100644 samples/rust/hostprogs/b.rs
create mode 100644 samples/rust/hostprogs/single.rs
create mode 100644 samples/rust/rust_chrdev.rs
create mode 100644 samples/rust/rust_minimal.rs
create mode 100644 samples/rust/rust_miscdev.rs
create mode 100644 samples/rust/rust_module_parameters.rs
create mode 100644 samples/rust/rust_netfilter.rs
create mode 100644 samples/rust/rust_platform.rs
create mode 100644 samples/rust/rust_print.rs
create mode 100644 samples/rust/rust_random.rs
create mode 100644 samples/rust/rust_semaphore.rs
create mode 100644 samples/rust/rust_semaphore_c.c
create mode 100644 samples/rust/rust_stack_probing.rs
create mode 100644 samples/rust/rust_sync.rs
diff --git a/samples/Kconfig b/samples/Kconfig
index 470ee3baf2e1..0d81c00289ee 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -263,6 +263,8 @@ config SAMPLE_CORESIGHT_SYSCFG
This demonstrates how a user may create their own CoreSight
configurations and easily load them into the system at runtime.
+source "samples/rust/Kconfig"
+
endif # SAMPLES
config HAVE_SAMPLE_FTRACE_DIRECT
diff --git a/samples/Makefile b/samples/Makefile
index 701e912ab5af..9832ef3f8fcb 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -35,3 +35,4 @@ subdir-$(CONFIG_SAMPLE_WATCH_QUEUE) += watch_queue
obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak/
obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG) += coresight/
obj-$(CONFIG_SAMPLE_FPROBE) += fprobe/
+obj-$(CONFIG_SAMPLES_RUST) += rust/
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
new file mode 100644
index 000000000000..4f90f8d69351
--- /dev/null
+++ b/samples/rust/Kconfig
@@ -0,0 +1,140 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig SAMPLES_RUST
+ bool "Rust samples"
+ depends on RUST
+ help
+ You can build sample Rust kernel code here.
+
+ If unsure, say N.
+
+if SAMPLES_RUST
+
+config SAMPLE_RUST_MINIMAL
+ tristate "Minimal"
+ help
+ This option builds the Rust minimal module sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_minimal.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_PRINT
+ tristate "Printing macros"
+ help
+ This option builds the Rust printing macros sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_print.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_MODULE_PARAMETERS
+ tristate "Module parameters"
+ help
+ This option builds the Rust module parameters sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_module_parameters.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_SYNC
+ tristate "Synchronisation primitives"
+ help
+ This option builds the Rust synchronisation primitives sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_sync.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_CHRDEV
+ tristate "Character device"
+ help
+ This option builds the Rust character device sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_chrdev.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_MISCDEV
+ tristate "Miscellaneous device"
+ help
+ This option builds the Rust miscellaneous device sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_miscdev.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_STACK_PROBING
+ tristate "Stack probing"
+ help
+ This option builds the Rust stack probing sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_stack_probing.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_SEMAPHORE
+ tristate "Semaphore"
+ help
+ This option builds the Rust semaphore sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_semaphore.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_SEMAPHORE_C
+ tristate "Semaphore (in C, for comparison)"
+ help
+ This option builds the Rust semaphore sample (in C, for comparison).
+
+ To compile this as a module, choose M here:
+ the module will be called rust_semaphore_c.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_RANDOM
+ tristate "Random"
+ help
+ This option builds the Rust random sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_random.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_PLATFORM
+ tristate "Platform device driver"
+ help
+ This option builds the Rust platform device driver sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_platform.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_NETFILTER
+ tristate "Network filter module"
+ help
+ This option builds the Rust netfilter module sample.
+
+ To compile this as a module, choose M here:
+ the module will be called rust_netfilter.
+
+ If unsure, say N.
+
+config SAMPLE_RUST_HOSTPROGS
+ bool "Host programs"
+ help
+ This option builds the Rust host program samples.
+
+ If unsure, say N.
+
+endif # SAMPLES_RUST
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
new file mode 100644
index 000000000000..fb5a205ebb8c
--- /dev/null
+++ b/samples/rust/Makefile
@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o
+obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_MODULE_PARAMETERS) += rust_module_parameters.o
+obj-$(CONFIG_SAMPLE_RUST_SYNC) += rust_sync.o
+obj-$(CONFIG_SAMPLE_RUST_CHRDEV) += rust_chrdev.o
+obj-$(CONFIG_SAMPLE_RUST_MISCDEV) += rust_miscdev.o
+obj-$(CONFIG_SAMPLE_RUST_STACK_PROBING) += rust_stack_probing.o
+obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE) += rust_semaphore.o
+obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE_C) += rust_semaphore_c.o
+obj-$(CONFIG_SAMPLE_RUST_RANDOM) += rust_random.o
+obj-$(CONFIG_SAMPLE_RUST_PLATFORM) += rust_platform.o
+obj-$(CONFIG_SAMPLE_RUST_NETFILTER) += rust_netfilter.o
+
+subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS) += hostprogs
diff --git a/samples/rust/hostprogs/.gitignore b/samples/rust/hostprogs/.gitignore
new file mode 100644
index 000000000000..a6c173da5048
--- /dev/null
+++ b/samples/rust/hostprogs/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+single
diff --git a/samples/rust/hostprogs/Makefile b/samples/rust/hostprogs/Makefile
new file mode 100644
index 000000000000..8ddcbd7416db
--- /dev/null
+++ b/samples/rust/hostprogs/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+hostprogs-always-y := single
+
+single-rust := y
diff --git a/samples/rust/hostprogs/a.rs b/samples/rust/hostprogs/a.rs
new file mode 100644
index 000000000000..f7a4a3d0f4e0
--- /dev/null
+++ b/samples/rust/hostprogs/a.rs
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample: module `a`.
+
+pub(crate) fn f(x: i32) {
+ println!("The number is {}.", x);
+}
diff --git a/samples/rust/hostprogs/b.rs b/samples/rust/hostprogs/b.rs
new file mode 100644
index 000000000000..c1675890648f
--- /dev/null
+++ b/samples/rust/hostprogs/b.rs
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample: module `b`.
+
+pub(crate) const CONSTANT: i32 = 42;
diff --git a/samples/rust/hostprogs/single.rs b/samples/rust/hostprogs/single.rs
new file mode 100644
index 000000000000..8c48a119339a
--- /dev/null
+++ b/samples/rust/hostprogs/single.rs
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample.
+
+mod a;
+mod b;
+
+fn main() {
+ println!("Hello world!");
+
+ a::f(b::CONSTANT);
+}
diff --git a/samples/rust/rust_chrdev.rs b/samples/rust/rust_chrdev.rs
new file mode 100644
index 000000000000..2e49c0056f59
--- /dev/null
+++ b/samples/rust/rust_chrdev.rs
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust character device sample.
+
+use kernel::prelude::*;
+use kernel::{chrdev, file};
+
+module! {
+ type: RustChrdev,
+ name: b"rust_chrdev",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust character device sample",
+ license: b"GPL v2",
+}
+
+struct RustFile;
+
+impl file::Operations for RustFile {
+ kernel::declare_file_operations!();
+
+ fn open(_shared: &(), _file: &file::File) -> Result {
+ Ok(())
+ }
+}
+
+struct RustChrdev {
+ _dev: Pin<Box<chrdev::Registration<2>>>,
+}
+
+impl kernel::Module for RustChrdev {
+ fn init(name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust character device sample (init)\n");
+
+ let mut chrdev_reg = chrdev::Registration::new_pinned(name, 0, module)?;
+
+ // Register the same kind of device twice, we're just demonstrating
+ // that you can use multiple minors. There are two minors in this case
+ // because its type is `chrdev::Registration<2>`
+ chrdev_reg.as_mut().register::<RustFile>()?;
+ chrdev_reg.as_mut().register::<RustFile>()?;
+
+ Ok(RustChrdev { _dev: chrdev_reg })
+ }
+}
+
+impl Drop for RustChrdev {
+ fn drop(&mut self) {
+ pr_info!("Rust character device sample (exit)\n");
+ }
+}
diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs
new file mode 100644
index 000000000000..83524f05bc35
--- /dev/null
+++ b/samples/rust/rust_minimal.rs
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust minimal sample.
+
+use kernel::prelude::*;
+
+module! {
+ type: RustMinimal,
+ name: b"rust_minimal",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust minimal sample",
+ license: b"GPL v2",
+}
+
+struct RustMinimal {
+ message: String,
+}
+
+impl kernel::Module for RustMinimal {
+ fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust minimal sample (init)\n");
+ pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
+
+ Ok(RustMinimal {
+ message: "on the heap!".try_to_owned()?,
+ })
+ }
+}
+
+impl Drop for RustMinimal {
+ fn drop(&mut self) {
+ pr_info!("My message is {}\n", self.message);
+ pr_info!("Rust minimal sample (exit)\n");
+ }
+}
diff --git a/samples/rust/rust_miscdev.rs b/samples/rust/rust_miscdev.rs
new file mode 100644
index 000000000000..079dc61b193f
--- /dev/null
+++ b/samples/rust/rust_miscdev.rs
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust miscellaneous device sample.
+
+use kernel::prelude::*;
+use kernel::{
+ file::{self, File},
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ miscdev,
+ sync::{CondVar, Mutex, Ref, RefBorrow, UniqueRef},
+};
+
+module! {
+ type: RustMiscdev,
+ name: b"rust_miscdev",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust miscellaneous device sample",
+ license: b"GPL v2",
+}
+
+const MAX_TOKENS: usize = 3;
+
+struct SharedStateInner {
+ token_count: usize,
+}
+
+struct SharedState {
+ state_changed: CondVar,
+ inner: Mutex<SharedStateInner>,
+}
+
+impl SharedState {
+ fn try_new() -> Result<Ref<Self>> {
+ let mut state = Pin::from(UniqueRef::try_new(Self {
+ // SAFETY: `condvar_init!` is called below.
+ state_changed: unsafe { CondVar::new() },
+ // SAFETY: `mutex_init!` is called below.
+ inner: unsafe { Mutex::new(SharedStateInner { token_count: 0 }) },
+ })?);
+
+ // SAFETY: `state_changed` is pinned when `state` is.
+ let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.state_changed) };
+ kernel::condvar_init!(pinned, "SharedState::state_changed");
+
+ // SAFETY: `inner` is pinned when `state` is.
+ let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.inner) };
+ kernel::mutex_init!(pinned, "SharedState::inner");
+
+ Ok(state.into())
+ }
+}
+
+struct Token;
+impl file::Operations for Token {
+ type Data = Ref<SharedState>;
+ type OpenData = Ref<SharedState>;
+
+ kernel::declare_file_operations!(read, write);
+
+ fn open(shared: &Ref<SharedState>, _file: &File) -> Result<Self::Data> {
+ Ok(shared.clone())
+ }
+
+ fn read(
+ shared: RefBorrow<'_, SharedState>,
+ _: &File,
+ data: &mut impl IoBufferWriter,
+ offset: u64,
+ ) -> Result<usize> {
+ // Succeed if the caller doesn't provide a buffer or if not at the start.
+ if data.is_empty() || offset != 0 {
+ return Ok(0);
+ }
+
+ {
+ let mut inner = shared.inner.lock();
+
+ // Wait until we are allowed to decrement the token count or a signal arrives.
+ while inner.token_count == 0 {
+ if shared.state_changed.wait(&mut inner) {
+ return Err(EINTR);
+ }
+ }
+
+ // Consume a token.
+ inner.token_count -= 1;
+ }
+
+ // Notify a possible writer waiting.
+ shared.state_changed.notify_all();
+
+ // Write a one-byte 1 to the reader.
+ data.write_slice(&[1u8; 1])?;
+ Ok(1)
+ }
+
+ fn write(
+ shared: RefBorrow<'_, SharedState>,
+ _: &File,
+ data: &mut impl IoBufferReader,
+ _offset: u64,
+ ) -> Result<usize> {
+ {
+ let mut inner = shared.inner.lock();
+
+ // Wait until we are allowed to increment the token count or a signal arrives.
+ while inner.token_count == MAX_TOKENS {
+ if shared.state_changed.wait(&mut inner) {
+ return Err(EINTR);
+ }
+ }
+
+ // Increment the number of token so that a reader can be released.
+ inner.token_count += 1;
+ }
+
+ // Notify a possible reader waiting.
+ shared.state_changed.notify_all();
+ Ok(data.len())
+ }
+}
+
+struct RustMiscdev {
+ _dev: Pin<Box<miscdev::Registration<Token>>>,
+}
+
+impl kernel::Module for RustMiscdev {
+ fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust miscellaneous device sample (init)\n");
+
+ let state = SharedState::try_new()?;
+
+ Ok(RustMiscdev {
+ _dev: miscdev::Registration::new_pinned(fmt!("{name}"), state)?,
+ })
+ }
+}
+
+impl Drop for RustMiscdev {
+ fn drop(&mut self) {
+ pr_info!("Rust miscellaneous device sample (exit)\n");
+ }
+}
diff --git a/samples/rust/rust_module_parameters.rs b/samples/rust/rust_module_parameters.rs
new file mode 100644
index 000000000000..6ccb1be7700f
--- /dev/null
+++ b/samples/rust/rust_module_parameters.rs
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust module parameters sample.
+
+use kernel::prelude::*;
+
+module! {
+ type: RustModuleParameters,
+ name: b"rust_module_parameters",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust module parameters sample",
+ license: b"GPL v2",
+ params: {
+ my_bool: bool {
+ default: true,
+ permissions: 0,
+ description: b"Example of bool",
+ },
+ my_i32: i32 {
+ default: 42,
+ permissions: 0o644,
+ description: b"Example of i32",
+ },
+ my_str: str {
+ default: b"default str val",
+ permissions: 0o644,
+ description: b"Example of a string param",
+ },
+ my_usize: usize {
+ default: 42,
+ permissions: 0o644,
+ description: b"Example of usize",
+ },
+ my_array: ArrayParam<i32, 3> {
+ default: [0, 1],
+ permissions: 0,
+ description: b"Example of array",
+ },
+ },
+}
+
+struct RustModuleParameters;
+
+impl kernel::Module for RustModuleParameters {
+ fn init(_name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust module parameters sample (init)\n");
+
+ {
+ let lock = module.kernel_param_lock();
+ pr_info!("Parameters:\n");
+ pr_info!(" my_bool: {}\n", my_bool.read());
+ pr_info!(" my_i32: {}\n", my_i32.read(&lock));
+ pr_info!(
+ " my_str: {}\n",
+ core::str::from_utf8(my_str.read(&lock))?
+ );
+ pr_info!(" my_usize: {}\n", my_usize.read(&lock));
+ pr_info!(" my_array: {:?}\n", my_array.read());
+ }
+
+ Ok(RustModuleParameters)
+ }
+}
+
+impl Drop for RustModuleParameters {
+ fn drop(&mut self) {
+ pr_info!("Rust module parameters sample (exit)\n");
+ }
+}
diff --git a/samples/rust/rust_netfilter.rs b/samples/rust/rust_netfilter.rs
new file mode 100644
index 000000000000..363a65bfee20
--- /dev/null
+++ b/samples/rust/rust_netfilter.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust netfilter sample.
+
+use kernel::net;
+use kernel::net::filter::{self as netfilter, inet, Disposition, Family};
+use kernel::prelude::*;
+
+module! {
+ type: RustNetfilter,
+ name: b"rust_netfilter",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust netfilter sample",
+ license: b"GPL v2",
+}
+
+struct RustNetfilter {
+ _in: Pin<Box<netfilter::Registration<Self>>>,
+ _out: Pin<Box<netfilter::Registration<Self>>>,
+}
+
+impl netfilter::Filter for RustNetfilter {
+ fn filter(_: (), skb: &net::SkBuff) -> Disposition {
+ let data = skb.head_data();
+ pr_info!(
+ "packet headlen={}, len={}, first bytes={:02x?}\n",
+ data.len(),
+ skb.len(),
+ &data[..core::cmp::min(10, data.len())]
+ );
+ Disposition::Accept
+ }
+}
+
+impl kernel::Module for RustNetfilter {
+ fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ Ok(Self {
+ _in: netfilter::Registration::new_pinned(
+ Family::INet(inet::Hook::PreRouting),
+ 0,
+ net::init_ns().into(),
+ None,
+ (),
+ )?,
+ _out: netfilter::Registration::new_pinned(
+ Family::INet(inet::Hook::PostRouting),
+ 0,
+ net::init_ns().into(),
+ None,
+ (),
+ )?,
+ })
+ }
+}
diff --git a/samples/rust/rust_platform.rs b/samples/rust/rust_platform.rs
new file mode 100644
index 000000000000..c0b740094c59
--- /dev/null
+++ b/samples/rust/rust_platform.rs
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust platform device driver sample.
+
+use kernel::{module_platform_driver, of, platform, prelude::*};
+
+module_platform_driver! {
+ type: Driver,
+ name: b"rust_platform",
+ license: b"GPL v2",
+}
+
+struct Driver;
+impl platform::Driver for Driver {
+ kernel::define_of_id_table! {(), [
+ (of::DeviceId::Compatible(b"rust,sample"), None),
+ ]}
+
+ fn probe(_dev: &mut platform::Device, _id_info: Option<&Self::IdInfo>) -> Result {
+ Ok(())
+ }
+}
diff --git a/samples/rust/rust_print.rs b/samples/rust/rust_print.rs
new file mode 100644
index 000000000000..dcc3ca9b84d4
--- /dev/null
+++ b/samples/rust/rust_print.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust printing macros sample.
+
+use kernel::prelude::*;
+use kernel::{pr_cont, str::CStr, ThisModule};
+
+module! {
+ type: RustPrint,
+ name: b"rust_print",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust printing macros sample",
+ license: b"GPL v2",
+}
+
+struct RustPrint;
+
+impl kernel::Module for RustPrint {
+ fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust printing macros sample (init)\n");
+
+ pr_emerg!("Emergency message (level 0) without args\n");
+ pr_alert!("Alert message (level 1) without args\n");
+ pr_crit!("Critical message (level 2) without args\n");
+ pr_err!("Error message (level 3) without args\n");
+ pr_warn!("Warning message (level 4) without args\n");
+ pr_notice!("Notice message (level 5) without args\n");
+ pr_info!("Info message (level 6) without args\n");
+
+ pr_info!("A line that");
+ pr_cont!(" is continued");
+ pr_cont!(" without args\n");
+
+ pr_emerg!("{} message (level {}) with args\n", "Emergency", 0);
+ pr_alert!("{} message (level {}) with args\n", "Alert", 1);
+ pr_crit!("{} message (level {}) with args\n", "Critical", 2);
+ pr_err!("{} message (level {}) with args\n", "Error", 3);
+ pr_warn!("{} message (level {}) with args\n", "Warning", 4);
+ pr_notice!("{} message (level {}) with args\n", "Notice", 5);
+ pr_info!("{} message (level {}) with args\n", "Info", 6);
+
+ pr_info!("A {} that", "line");
+ pr_cont!(" is {}", "continued");
+ pr_cont!(" with {}\n", "args");
+
+ Ok(RustPrint)
+ }
+}
+
+impl Drop for RustPrint {
+ fn drop(&mut self) {
+ pr_info!("Rust printing macros sample (exit)\n");
+ }
+}
diff --git a/samples/rust/rust_random.rs b/samples/rust/rust_random.rs
new file mode 100644
index 000000000000..241fbbfb8673
--- /dev/null
+++ b/samples/rust/rust_random.rs
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust random device.
+//!
+//! Adapted from Alex Gaynor's original available at
+//! <https://github.com/alex/just-use/blob/master/src/lib.rs>.
+
+use kernel::{
+ file::{self, File},
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ prelude::*,
+};
+
+struct RandomFile;
+
+impl file::Operations for RandomFile {
+ kernel::declare_file_operations!(read, write, read_iter, write_iter);
+
+ fn open(_data: &(), _file: &File) -> Result {
+ Ok(())
+ }
+
+ fn read(_this: (), file: &File, buf: &mut impl IoBufferWriter, _: u64) -> Result<usize> {
+ let total_len = buf.len();
+ let mut chunkbuf = [0; 256];
+
+ while !buf.is_empty() {
+ let len = chunkbuf.len().min(buf.len());
+ let chunk = &mut chunkbuf[0..len];
+
+ if file.is_blocking() {
+ kernel::random::getrandom(chunk)?;
+ } else {
+ kernel::random::getrandom_nonblock(chunk)?;
+ }
+ buf.write_slice(chunk)?;
+ }
+ Ok(total_len)
+ }
+
+ fn write(_this: (), _file: &File, buf: &mut impl IoBufferReader, _: u64) -> Result<usize> {
+ let total_len = buf.len();
+ let mut chunkbuf = [0; 256];
+ while !buf.is_empty() {
+ let len = chunkbuf.len().min(buf.len());
+ let chunk = &mut chunkbuf[0..len];
+ buf.read_slice(chunk)?;
+ kernel::random::add_randomness(chunk);
+ }
+ Ok(total_len)
+ }
+}
+
+module_misc_device! {
+ type: RandomFile,
+ name: b"rust_random",
+ author: b"Rust for Linux Contributors",
+ description: b"Just use /dev/urandom: Now with early-boot safety",
+ license: b"GPL v2",
+}
diff --git a/samples/rust/rust_semaphore.rs b/samples/rust/rust_semaphore.rs
new file mode 100644
index 000000000000..01230cd45961
--- /dev/null
+++ b/samples/rust/rust_semaphore.rs
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust semaphore sample.
+//!
+//! A counting semaphore that can be used by userspace.
+//!
+//! The count is incremented by writes to the device. A write of `n` bytes results in an increment
+//! of `n`. It is decremented by reads; each read results in the count being decremented by 1. If
+//! the count is already zero, a read will block until another write increments it.
+//!
+//! This can be used in user space from the shell for example as follows (assuming a node called
+//! `semaphore`): `cat semaphore` decrements the count by 1 (waiting for it to become non-zero
+//! before decrementing); `echo -n 123 > semaphore` increments the semaphore by 3, potentially
+//! unblocking up to 3 blocked readers.
+
+use core::sync::atomic::{AtomicU64, Ordering};
+use kernel::{
+ condvar_init, declare_file_operations,
+ file::{self, File, IoctlCommand, IoctlHandler},
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ miscdev::Registration,
+ mutex_init,
+ prelude::*,
+ sync::{CondVar, Mutex, Ref, UniqueRef},
+ user_ptr::{UserSlicePtrReader, UserSlicePtrWriter},
+};
+
+module! {
+ type: RustSemaphore,
+ name: b"rust_semaphore",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust semaphore sample",
+ license: b"GPL v2",
+}
+
+struct SemaphoreInner {
+ count: usize,
+ max_seen: usize,
+}
+
+struct Semaphore {
+ changed: CondVar,
+ inner: Mutex<SemaphoreInner>,
+}
+
+struct FileState {
+ read_count: AtomicU64,
+ shared: Ref<Semaphore>,
+}
+
+impl FileState {
+ fn consume(&self) -> Result {
+ let mut inner = self.shared.inner.lock();
+ while inner.count == 0 {
+ if self.shared.changed.wait(&mut inner) {
+ return Err(EINTR);
+ }
+ }
+ inner.count -= 1;
+ Ok(())
+ }
+}
+
+impl file::Operations for FileState {
+ type Data = Box<Self>;
+ type OpenData = Ref<Semaphore>;
+
+ declare_file_operations!(read, write, ioctl);
+
+ fn open(shared: &Ref<Semaphore>, _file: &File) -> Result<Box<Self>> {
+ Ok(Box::try_new(Self {
+ read_count: AtomicU64::new(0),
+ shared: shared.clone(),
+ })?)
+ }
+
+ fn read(this: &Self, _: &File, data: &mut impl IoBufferWriter, offset: u64) -> Result<usize> {
+ if data.is_empty() || offset > 0 {
+ return Ok(0);
+ }
+ this.consume()?;
+ data.write_slice(&[0u8; 1])?;
+ this.read_count.fetch_add(1, Ordering::Relaxed);
+ Ok(1)
+ }
+
+ fn write(this: &Self, _: &File, data: &mut impl IoBufferReader, _offs: u64) -> Result<usize> {
+ {
+ let mut inner = this.shared.inner.lock();
+ inner.count = inner.count.saturating_add(data.len());
+ if inner.count > inner.max_seen {
+ inner.max_seen = inner.count;
+ }
+ }
+
+ this.shared.changed.notify_all();
+ Ok(data.len())
+ }
+
+ fn ioctl(this: &Self, file: &File, cmd: &mut IoctlCommand) -> Result<i32> {
+ cmd.dispatch::<Self>(this, file)
+ }
+}
+
+struct RustSemaphore {
+ _dev: Pin<Box<Registration<FileState>>>,
+}
+
+impl kernel::Module for RustSemaphore {
+ fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust semaphore sample (init)\n");
+
+ let mut sema = Pin::from(UniqueRef::try_new(Semaphore {
+ // SAFETY: `condvar_init!` is called below.
+ changed: unsafe { CondVar::new() },
+
+ // SAFETY: `mutex_init!` is called below.
+ inner: unsafe {
+ Mutex::new(SemaphoreInner {
+ count: 0,
+ max_seen: 0,
+ })
+ },
+ })?);
+
+ // SAFETY: `changed` is pinned when `sema` is.
+ let pinned = unsafe { sema.as_mut().map_unchecked_mut(|s| &mut s.changed) };
+ condvar_init!(pinned, "Semaphore::changed");
+
+ // SAFETY: `inner` is pinned when `sema` is.
+ let pinned = unsafe { sema.as_mut().map_unchecked_mut(|s| &mut s.inner) };
+ mutex_init!(pinned, "Semaphore::inner");
+
+ Ok(Self {
+ _dev: Registration::new_pinned(fmt!("{name}"), sema.into())?,
+ })
+ }
+}
+
+impl Drop for RustSemaphore {
+ fn drop(&mut self) {
+ pr_info!("Rust semaphore sample (exit)\n");
+ }
+}
+
+const IOCTL_GET_READ_COUNT: u32 = 0x80086301;
+const IOCTL_SET_READ_COUNT: u32 = 0x40086301;
+
+impl IoctlHandler for FileState {
+ type Target<'a> = &'a Self;
+
+ fn read(this: &Self, _: &File, cmd: u32, writer: &mut UserSlicePtrWriter) -> Result<i32> {
+ match cmd {
+ IOCTL_GET_READ_COUNT => {
+ writer.write(&this.read_count.load(Ordering::Relaxed))?;
+ Ok(0)
+ }
+ _ => Err(EINVAL),
+ }
+ }
+
+ fn write(this: &Self, _: &File, cmd: u32, reader: &mut UserSlicePtrReader) -> Result<i32> {
+ match cmd {
+ IOCTL_SET_READ_COUNT => {
+ this.read_count.store(reader.read()?, Ordering::Relaxed);
+ Ok(0)
+ }
+ _ => Err(EINVAL),
+ }
+ }
+}
diff --git a/samples/rust/rust_semaphore_c.c b/samples/rust/rust_semaphore_c.c
new file mode 100644
index 000000000000..cdc121d4030d
--- /dev/null
+++ b/samples/rust/rust_semaphore_c.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Rust semaphore sample (in C, for comparison)
+ *
+ * This is a C implementation of `rust_semaphore.rs`. Refer to the description
+ * in that file for details on the device.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/refcount.h>
+#include <linux/wait.h>
+
+#define IOCTL_GET_READ_COUNT _IOR('c', 1, u64)
+#define IOCTL_SET_READ_COUNT _IOW('c', 1, u64)
+
+struct semaphore_state {
+ struct kref ref;
+ struct miscdevice miscdev;
+ wait_queue_head_t changed;
+ struct mutex mutex;
+ size_t count;
+ size_t max_seen;
+};
+
+struct file_state {
+ atomic64_t read_count;
+ struct semaphore_state *shared;
+};
+
+static int semaphore_consume(struct semaphore_state *state)
+{
+ DEFINE_WAIT(wait);
+
+ mutex_lock(&state->mutex);
+ while (state->count == 0) {
+ prepare_to_wait(&state->changed, &wait, TASK_INTERRUPTIBLE);
+ mutex_unlock(&state->mutex);
+ schedule();
+ finish_wait(&state->changed, &wait);
+ if (signal_pending(current))
+ return -EINTR;
+ mutex_lock(&state->mutex);
+ }
+
+ state->count--;
+ mutex_unlock(&state->mutex);
+
+ return 0;
+}
+
+static int semaphore_open(struct inode *nodp, struct file *filp)
+{
+ struct semaphore_state *shared =
+ container_of(filp->private_data, struct semaphore_state, miscdev);
+ struct file_state *state;
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+
+ kref_get(&shared->ref);
+ state->shared = shared;
+ atomic64_set(&state->read_count, 0);
+
+ filp->private_data = state;
+
+ return 0;
+}
+
+static ssize_t semaphore_write(struct file *filp, const char __user *buffer, size_t count,
+ loff_t *ppos)
+{
+ struct file_state *state = filp->private_data;
+ struct semaphore_state *shared = state->shared;
+
+ mutex_lock(&shared->mutex);
+
+ shared->count += count;
+ if (shared->count < count)
+ shared->count = SIZE_MAX;
+
+ if (shared->count > shared->max_seen)
+ shared->max_seen = shared->count;
+
+ mutex_unlock(&shared->mutex);
+
+ wake_up_all(&shared->changed);
+
+ return count;
+}
+
+static ssize_t semaphore_read(struct file *filp, char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct file_state *state = filp->private_data;
+ char c = 0;
+ int ret;
+
+ if (count == 0 || *ppos > 0)
+ return 0;
+
+ ret = semaphore_consume(state->shared);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(buffer, &c, sizeof(c)))
+ return -EFAULT;
+
+ atomic64_add(1, &state->read_count);
+ *ppos += 1;
+ return 1;
+}
+
+static long semaphore_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ struct file_state *state = filp->private_data;
+ void __user *buffer = (void __user *)arg;
+ u64 value;
+
+ switch (cmd) {
+ case IOCTL_GET_READ_COUNT:
+ value = atomic64_read(&state->read_count);
+ if (copy_to_user(buffer, &value, sizeof(value)))
+ return -EFAULT;
+ return 0;
+ case IOCTL_SET_READ_COUNT:
+ if (copy_from_user(&value, buffer, sizeof(value)))
+ return -EFAULT;
+ atomic64_set(&state->read_count, value);
+ return 0;
+ default:
+ return -EINVAL;
+ }
+}
+
+static void semaphore_free(struct kref *kref)
+{
+ struct semaphore_state *device;
+
+ device = container_of(kref, struct semaphore_state, ref);
+ kfree(device);
+}
+
+static int semaphore_release(struct inode *nodp, struct file *filp)
+{
+ struct file_state *state = filp->private_data;
+
+ kref_put(&state->shared->ref, semaphore_free);
+ kfree(state);
+ return 0;
+}
+
+static const struct file_operations semaphore_fops = {
+ .owner = THIS_MODULE,
+ .open = semaphore_open,
+ .read = semaphore_read,
+ .write = semaphore_write,
+ .compat_ioctl = semaphore_ioctl,
+ .release = semaphore_release,
+};
+
+static struct semaphore_state *device;
+
+static int __init semaphore_init(void)
+{
+ int ret;
+ struct semaphore_state *state;
+
+ pr_info("Rust semaphore sample (in C, for comparison) (init)\n");
+
+ state = kzalloc(sizeof(*state), GFP_KERNEL);
+ if (!state)
+ return -ENOMEM;
+
+ mutex_init(&state->mutex);
+ kref_init(&state->ref);
+ init_waitqueue_head(&state->changed);
+
+ state->miscdev.fops = &semaphore_fops;
+ state->miscdev.minor = MISC_DYNAMIC_MINOR;
+ state->miscdev.name = "semaphore";
+
+ ret = misc_register(&state->miscdev);
+ if (ret < 0) {
+ kfree(state);
+ return ret;
+ }
+
+ device = state;
+
+ return 0;
+}
+
+static void __exit semaphore_exit(void)
+{
+ pr_info("Rust semaphore sample (in C, for comparison) (exit)\n");
+
+ misc_deregister(&device->miscdev);
+ kref_put(&device->ref, semaphore_free);
+}
+
+module_init(semaphore_init);
+module_exit(semaphore_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Rust for Linux Contributors");
+MODULE_DESCRIPTION("Rust semaphore sample (in C, for comparison)");
diff --git a/samples/rust/rust_stack_probing.rs b/samples/rust/rust_stack_probing.rs
new file mode 100644
index 000000000000..725755f42314
--- /dev/null
+++ b/samples/rust/rust_stack_probing.rs
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust stack probing sample.
+
+use kernel::prelude::*;
+
+module! {
+ type: RustStackProbing,
+ name: b"rust_stack_probing",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust stack probing sample",
+ license: b"GPL v2",
+}
+
+struct RustStackProbing;
+
+impl kernel::Module for RustStackProbing {
+ fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust stack probing sample (init)\n");
+
+ // Including this large variable on the stack will trigger
+ // stack probing on the supported archs.
+ // This will verify that stack probing does not lead to
+ // any errors if we need to link `__rust_probestack`.
+ let x: [u64; 514] = core::hint::black_box([5; 514]);
+ pr_info!("Large array has length: {}\n", x.len());
+
+ Ok(RustStackProbing)
+ }
+}
+
+impl Drop for RustStackProbing {
+ fn drop(&mut self) {
+ pr_info!("Rust stack probing sample (exit)\n");
+ }
+}
diff --git a/samples/rust/rust_sync.rs b/samples/rust/rust_sync.rs
new file mode 100644
index 000000000000..d87d72cf6d9a
--- /dev/null
+++ b/samples/rust/rust_sync.rs
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust synchronisation primitives sample.
+
+use kernel::prelude::*;
+use kernel::{
+ condvar_init, mutex_init, spinlock_init,
+ sync::{CondVar, Mutex, SpinLock},
+};
+
+module! {
+ type: RustSync,
+ name: b"rust_sync",
+ author: b"Rust for Linux Contributors",
+ description: b"Rust synchronisation primitives sample",
+ license: b"GPL v2",
+}
+
+kernel::init_static_sync! {
+ static SAMPLE_MUTEX: Mutex<u32> = 10;
+ static SAMPLE_CONDVAR: CondVar;
+}
+
+struct RustSync;
+
+impl kernel::Module for RustSync {
+ fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+ pr_info!("Rust synchronisation primitives sample (init)\n");
+
+ // Test mutexes.
+ {
+ // SAFETY: `init` is called below.
+ let mut data = Pin::from(Box::try_new(unsafe { Mutex::new(0) })?);
+ mutex_init!(data.as_mut(), "RustSync::init::data1");
+ *data.lock() = 10;
+ pr_info!("Value: {}\n", *data.lock());
+
+ // SAFETY: `init` is called below.
+ let mut cv = Pin::from(Box::try_new(unsafe { CondVar::new() })?);
+ condvar_init!(cv.as_mut(), "RustSync::init::cv1");
+
+ {
+ let mut guard = data.lock();
+ while *guard != 10 {
+ let _ = cv.wait(&mut guard);
+ }
+ }
+ cv.notify_one();
+ cv.notify_all();
+ cv.free_waiters();
+ }
+
+ // Test static mutex + condvar.
+ *SAMPLE_MUTEX.lock() = 20;
+
+ {
+ let mut guard = SAMPLE_MUTEX.lock();
+ while *guard != 20 {
+ let _ = SAMPLE_CONDVAR.wait(&mut guard);
+ }
+ }
+
+ // Test spinlocks.
+ {
+ // SAFETY: `init` is called below.
+ let mut data = Pin::from(Box::try_new(unsafe { SpinLock::new(0) })?);
+ spinlock_init!(data.as_mut(), "RustSync::init::data2");
+ *data.lock() = 10;
+ pr_info!("Value: {}\n", *data.lock());
+
+ // SAFETY: `init` is called below.
+ let mut cv = Pin::from(Box::try_new(unsafe { CondVar::new() })?);
+ condvar_init!(cv.as_mut(), "RustSync::init::cv2");
+ {
+ let mut guard = data.lock();
+ while *guard != 10 {
+ let _ = cv.wait(&mut guard);
+ }
+ }
+ cv.notify_one();
+ cv.notify_all();
+ cv.free_waiters();
+ }
+
+ Ok(RustSync)
+ }
+}
+
+impl Drop for RustSync {
+ fn drop(&mut self) {
+ pr_info!("Rust synchronisation primitives sample (exit)\n");
+ }
+}
--
2.35.3
Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc. For instance,
the following code:
pub mod my_module {
pub struct MyType;
pub struct MyGenericType<T>(T);
pub trait MyTrait {
fn my_method() -> u32;
}
impl MyTrait for MyGenericType<MyType> {
fn my_method() -> u32 {
42
}
}
}
generates a symbol of length 96 when using the upcoming v0 mangling scheme:
_RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method
At the moment, Rust symbols may reach up to 300 in length.
Setting 512 as the maximum seems like a reasonable choice to
keep some headroom.
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Boqun Feng <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
This is a prerequisite patch, independently submitted at:
https://lore.kernel.org/lkml/[email protected]/
include/linux/kallsyms.h | 2 +-
kernel/livepatch/core.c | 4 ++--
scripts/kallsyms.c | 4 ++--
tools/include/linux/kallsyms.h | 2 +-
tools/lib/perf/include/perf/event.h | 2 +-
tools/lib/symbol/kallsyms.h | 2 +-
6 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index ce1bd2fbf23e..e5ad6e31697d 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -15,7 +15,7 @@
#include <asm/sections.h>
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
#define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \
(KSYM_NAME_LEN - 1) + \
2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index bc475e62279d..ec06ce59d728 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
* we use the smallest/strictest upper bound possible (56, based on
* the current definition of MODULE_NAME_LEN) to prevent overflows.
*/
- BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
+ BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
relas = (Elf_Rela *) relasec->sh_addr;
/* For each rela in this klp relocation section */
@@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
/* Format: .klp.sym.sym_objname.sym_name,sympos */
cnt = sscanf(strtab + sym->st_name,
- ".klp.sym.%55[^.].%127[^,],%lu",
+ ".klp.sym.%55[^.].%511[^,],%lu",
sym_objname, sym_name, &sympos);
if (cnt != 3) {
pr_err("symbol %s has an incorrectly formatted name\n",
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 7e99799aa7b9..275044b840dc 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -30,10 +30,10 @@
#define _stringify_1(x) #x
#define _stringify(x) _stringify_1(x)
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
/* A substantially bigger size than the current maximum. */
-#define KSYM_NAME_LEN_BUFFER 512
+#define KSYM_NAME_LEN_BUFFER 2048
_Static_assert(
KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
"Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index efb6c3f5f2a9..5a37ccbec54f 100644
--- a/tools/include/linux/kallsyms.h
+++ b/tools/include/linux/kallsyms.h
@@ -6,7 +6,7 @@
#include <stdio.h>
#include <unistd.h>
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
struct module;
diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index e7758707cadd..116a80c31675 100644
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -95,7 +95,7 @@ struct perf_record_throttle {
};
#ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
#endif
struct perf_record_ksymbol {
diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h
index 72ab9870454b..542f9b059c3b 100644
--- a/tools/lib/symbol/kallsyms.h
+++ b/tools/lib/symbol/kallsyms.h
@@ -7,7 +7,7 @@
#include <linux/types.h>
#ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
#endif
static inline u8 kallsyms2elf_binding(char type)
--
2.35.3
The `kunit_do_failed_assertion` function passes its
`struct kunit_assert` argument to `kunit_fail`. This one,
in turn, calls its `format` field passing the assert again
as a `const` pointer.
Therefore, the whole chain may be made `const`.
Reviewed-by: Daniel Latypov <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
This is a prerequisite patch, independently submitted at:
https://lore.kernel.org/lkml/[email protected]/
include/kunit/test.h | 2 +-
lib/kunit/test.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/kunit/test.h b/include/kunit/test.h
index 00b9ff7783ab..2eff4f1beb42 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -774,7 +774,7 @@ void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...);
void kunit_do_failed_assertion(struct kunit *test,
const struct kunit_loc *loc,
enum kunit_assert_type type,
- struct kunit_assert *assert,
+ const struct kunit_assert *assert,
const char *fmt, ...);
#define KUNIT_ASSERTION(test, assert_type, pass, assert_class, INITIALIZER, fmt, ...) do { \
diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 3bca3bf5c15b..b84aed09a009 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -241,7 +241,7 @@ static void kunit_print_string_stream(struct kunit *test,
}
static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
- enum kunit_assert_type type, struct kunit_assert *assert,
+ enum kunit_assert_type type, const struct kunit_assert *assert,
const struct va_format *message)
{
struct string_stream *stream;
@@ -281,7 +281,7 @@ static void __noreturn kunit_abort(struct kunit *test)
void kunit_do_failed_assertion(struct kunit *test,
const struct kunit_loc *loc,
enum kunit_assert_type type,
- struct kunit_assert *assert,
+ const struct kunit_assert *assert,
const char *fmt, ...)
{
va_list args;
--
2.35.3
This customizes the subset of the Rust standard library `alloc` that
was just imported as-is, mainly by:
- Adding SPDX license identifiers.
- Skipping `rc` and `sync` modules via new `cfg`s.
- Skipping the `vec!` macro.
- Addding fallible (`try_*`) versions of existing infallible methods
(i.e. returning a `Result` instead of panicking).
Since the standard library requires stable/unstable attributes,
these additions are annotated with:
#[stable(feature = "kernel", since = "1.0.0")]
Using "kernel" as the feature allows to have the additions
clearly marked. The "1.0.0" version is just a placeholder.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Matthew Bakhtiari <[email protected]>
Signed-off-by: Matthew Bakhtiari <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
rust/alloc/README.md | 32 +++
rust/alloc/alloc.rs | 2 +
rust/alloc/borrow.rs | 2 +
rust/alloc/boxed.rs | 2 +
rust/alloc/collections/mod.rs | 2 +
rust/alloc/fmt.rs | 2 +
rust/alloc/lib.rs | 5 +-
rust/alloc/macros.rs | 4 +-
rust/alloc/raw_vec.rs | 50 ++++-
rust/alloc/slice.rs | 93 ++++++++-
rust/alloc/str.rs | 19 ++
rust/alloc/string.rs | 6 +-
rust/alloc/vec/drain.rs | 2 +
rust/alloc/vec/drain_filter.rs | 2 +
rust/alloc/vec/into_iter.rs | 2 +
rust/alloc/vec/is_zero.rs | 2 +
rust/alloc/vec/mod.rs | 313 +++++++++++++++++++++++++++++-
rust/alloc/vec/partial_eq.rs | 2 +
rust/alloc/vec/set_len_on_drop.rs | 2 +
rust/alloc/vec/spec_extend.rs | 87 +++++++++
20 files changed, 622 insertions(+), 9 deletions(-)
create mode 100644 rust/alloc/README.md
diff --git a/rust/alloc/README.md b/rust/alloc/README.md
new file mode 100644
index 000000000000..a1bcc2cef0e6
--- /dev/null
+++ b/rust/alloc/README.md
@@ -0,0 +1,32 @@
+# `alloc`
+
+These source files come from the Rust standard library, hosted in
+the https://github.com/rust-lang/rust repository. For copyright
+details, see https://github.com/rust-lang/rust/blob/master/COPYRIGHT.
+
+Please note that these files should be kept as close as possible to
+upstream. In general, only additions should be performed (e.g. new
+methods). Eventually, changes should make it into upstream so that,
+at some point, this fork can be dropped from the kernel tree.
+
+
+## Rationale
+
+On one hand, kernel folks wanted to keep `alloc` in-tree to have more
+freedom in both workflow and actual features if actually needed
+(e.g. receiver types if we ended up using them), which is reasonable.
+
+On the other hand, Rust folks wanted to keep `alloc` as close as
+upstream as possible and avoid as much divergence as possible, which
+is also reasonable.
+
+We agreed on a middle-ground: we would keep a subset of `alloc`
+in-tree that would be as small and as close as possible to upstream.
+Then, upstream can start adding the functions that we add to `alloc`
+etc., until we reach a point where the kernel already knows exactly
+what it needs in `alloc` and all the new methods are merged into
+upstream, so that we can drop `alloc` from the kernel tree and go back
+to using the upstream one.
+
+By doing this, the kernel can go a bit faster now, and Rust can
+slowly incorporate and discuss the changes as needed.
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
index 9d4f9af91a5e..cea3b747673f 100644
--- a/rust/alloc/alloc.rs
+++ b/rust/alloc/alloc.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! Memory allocation APIs
#![stable(feature = "alloc_module", since = "1.28.0")]
diff --git a/rust/alloc/borrow.rs b/rust/alloc/borrow.rs
index 63234ee91f09..8e1d8a764641 100644
--- a/rust/alloc/borrow.rs
+++ b/rust/alloc/borrow.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! A module for working with borrowed data.
#![stable(feature = "rust1", since = "1.0.0")]
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
index f753189c6830..921fcef75e4b 100644
--- a/rust/alloc/boxed.rs
+++ b/rust/alloc/boxed.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! A pointer type for heap allocation.
//!
//! [`Box<T>`], casually referred to as a 'box', provides the simplest form of
diff --git a/rust/alloc/collections/mod.rs b/rust/alloc/collections/mod.rs
index 628a5b155673..1eec265b28f8 100644
--- a/rust/alloc/collections/mod.rs
+++ b/rust/alloc/collections/mod.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! Collection types.
#![stable(feature = "rust1", since = "1.0.0")]
diff --git a/rust/alloc/fmt.rs b/rust/alloc/fmt.rs
index aeb7554f8e91..be75e6637442 100644
--- a/rust/alloc/fmt.rs
+++ b/rust/alloc/fmt.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! Utilities for formatting and printing `String`s.
//!
//! This module contains the runtime support for the [`format!`] syntax extension.
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
index 6da32df57efb..085dc005170a 100644
--- a/rust/alloc/lib.rs
+++ b/rust/alloc/lib.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! # The Rust core allocation and collections library
//!
//! This library provides smart pointers and collections for managing
@@ -204,11 +206,12 @@ mod boxed {
pub mod borrow;
pub mod collections;
pub mod fmt;
+#[cfg(not(no_rc))]
pub mod rc;
pub mod slice;
pub mod str;
pub mod string;
-#[cfg(target_has_atomic = "ptr")]
+#[cfg(all(not(no_sync), target_has_atomic = "ptr"))]
pub mod sync;
#[cfg(all(not(no_global_oom_handling), target_has_atomic = "ptr"))]
pub mod task;
diff --git a/rust/alloc/macros.rs b/rust/alloc/macros.rs
index d3e9e65c3fe5..47ebcd5277d1 100644
--- a/rust/alloc/macros.rs
+++ b/rust/alloc/macros.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
/// Creates a [`Vec`] containing the arguments.
///
/// `vec!` allows `Vec`s to be defined with the same syntax as array expressions.
@@ -34,7 +36,7 @@
/// be mindful of side effects.
///
/// [`Vec`]: crate::vec::Vec
-#[cfg(not(test))]
+#[cfg(all(not(no_global_oom_handling), not(test)))]
#[macro_export]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_diagnostic_item = "vec_macro"]
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
index 8fa0242ca9a9..018c4657f580 100644
--- a/rust/alloc/raw_vec.rs
+++ b/rust/alloc/raw_vec.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
#![unstable(feature = "raw_vec_internals", reason = "unstable const warnings", issue = "none")]
use core::alloc::LayoutError;
@@ -18,10 +20,10 @@ use crate::collections::TryReserveErrorKind::*;
#[cfg(test)]
mod tests;
-#[cfg(not(no_global_oom_handling))]
enum AllocInit {
/// The contents of the new memory are uninitialized.
Uninitialized,
+ #[allow(dead_code)]
/// The new memory is guaranteed to be zeroed.
Zeroed,
}
@@ -132,6 +134,13 @@ impl<T, A: Allocator> RawVec<T, A> {
Self::allocate_in(capacity, AllocInit::Uninitialized, alloc)
}
+ /// Like `try_with_capacity`, but parameterized over the choice of
+ /// allocator for the returned `RawVec`.
+ #[inline]
+ pub fn try_with_capacity_in(capacity: usize, alloc: A) -> Result<Self, TryReserveError> {
+ Self::try_allocate_in(capacity, AllocInit::Uninitialized, alloc)
+ }
+
/// Like `with_capacity_zeroed`, but parameterized over the choice
/// of allocator for the returned `RawVec`.
#[cfg(not(no_global_oom_handling))]
@@ -201,6 +210,29 @@ impl<T, A: Allocator> RawVec<T, A> {
}
}
+ fn try_allocate_in(capacity: usize, init: AllocInit, alloc: A) -> Result<Self, TryReserveError> {
+ if mem::size_of::<T>() == 0 {
+ return Ok(Self::new_in(alloc));
+ }
+
+ let layout = Layout::array::<T>(capacity).map_err(|_| CapacityOverflow)?;
+ alloc_guard(layout.size())?;
+ let result = match init {
+ AllocInit::Uninitialized => alloc.allocate(layout),
+ AllocInit::Zeroed => alloc.allocate_zeroed(layout),
+ };
+ let ptr = result.map_err(|_| AllocError { layout, non_exhaustive: () })?;
+
+ // Allocators currently return a `NonNull<[u8]>` whose length
+ // matches the size requested. If that ever changes, the capacity
+ // here should change to `ptr.len() / mem::size_of::<T>()`.
+ Ok(Self {
+ ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
+ cap: capacity,
+ alloc,
+ })
+ }
+
/// Reconstitutes a `RawVec` from a pointer, capacity, and allocator.
///
/// # Safety
@@ -309,6 +341,12 @@ impl<T, A: Allocator> RawVec<T, A> {
}
}
+ /// The same as `reserve_for_push`, but returns on errors instead of panicking or aborting.
+ #[inline(never)]
+ pub fn try_reserve_for_push(&mut self, len: usize) -> Result<(), TryReserveError> {
+ self.grow_amortized(len, 1)
+ }
+
/// Ensures that the buffer contains at least enough space to hold `len +
/// additional` elements. If it doesn't already, will reallocate the
/// minimum possible amount of memory necessary. Generally this will be
@@ -354,6 +392,16 @@ impl<T, A: Allocator> RawVec<T, A> {
pub fn shrink_to_fit(&mut self, cap: usize) {
handle_reserve(self.shrink(cap));
}
+
+ /// Tries to shrink the buffer down to the specified capacity. If the given amount
+ /// is 0, actually completely deallocates.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the given amount is *larger* than the current capacity.
+ pub fn try_shrink_to_fit(&mut self, cap: usize) -> Result<(), TryReserveError> {
+ self.shrink(cap)
+ }
}
impl<T, A: Allocator> RawVec<T, A> {
diff --git a/rust/alloc/slice.rs b/rust/alloc/slice.rs
index f0397d08f95a..8cb5170f639d 100644
--- a/rust/alloc/slice.rs
+++ b/rust/alloc/slice.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! A dynamically-sized view into a contiguous sequence, `[T]`.
//!
//! *[See also the slice primitive type](slice).*
@@ -93,11 +95,11 @@ use core::mem::size_of;
use core::ptr;
use crate::alloc::Allocator;
-#[cfg(not(no_global_oom_handling))]
use crate::alloc::Global;
#[cfg(not(no_global_oom_handling))]
use crate::borrow::ToOwned;
use crate::boxed::Box;
+use crate::collections::TryReserveError;
use crate::vec::Vec;
#[unstable(feature = "slice_range", issue = "76393")]
@@ -157,6 +159,7 @@ mod hack {
use core::alloc::Allocator;
use crate::boxed::Box;
+ use crate::collections::TryReserveError;
use crate::vec::Vec;
// We shouldn't add inline attribute to this since this is used in
@@ -176,6 +179,11 @@ mod hack {
T::to_vec(s, alloc)
}
+ #[inline]
+ pub fn try_to_vec<T: TryConvertVec, A: Allocator>(s: &[T], alloc: A) -> Result<Vec<T, A>, TryReserveError> {
+ T::try_to_vec(s, alloc)
+ }
+
#[cfg(not(no_global_oom_handling))]
pub trait ConvertVec {
fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A>
@@ -183,6 +191,12 @@ mod hack {
Self: Sized;
}
+ pub trait TryConvertVec {
+ fn try_to_vec<A: Allocator>(s: &[Self], alloc: A) -> Result<Vec<Self, A>, TryReserveError>
+ where
+ Self: Sized;
+ }
+
#[cfg(not(no_global_oom_handling))]
impl<T: Clone> ConvertVec for T {
#[inline]
@@ -235,6 +249,42 @@ mod hack {
v
}
}
+
+ impl<T: Clone> TryConvertVec for T {
+ #[inline]
+ default fn try_to_vec<A: Allocator>(s: &[Self], alloc: A) -> Result<Vec<Self, A>, TryReserveError> {
+ struct DropGuard<'a, T, A: Allocator> {
+ vec: &'a mut Vec<T, A>,
+ num_init: usize,
+ }
+ impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> {
+ #[inline]
+ fn drop(&mut self) {
+ // SAFETY:
+ // items were marked initialized in the loop below
+ unsafe {
+ self.vec.set_len(self.num_init);
+ }
+ }
+ }
+ let mut vec = Vec::try_with_capacity_in(s.len(), alloc)?;
+ let mut guard = DropGuard { vec: &mut vec, num_init: 0 };
+ let slots = guard.vec.spare_capacity_mut();
+ // .take(slots.len()) is necessary for LLVM to remove bounds checks
+ // and has better codegen than zip.
+ for (i, b) in s.iter().enumerate().take(slots.len()) {
+ guard.num_init = i;
+ slots[i].write(b.clone());
+ }
+ core::mem::forget(guard);
+ // SAFETY:
+ // the vec was allocated and initialized above to at least this length.
+ unsafe {
+ vec.set_len(s.len());
+ }
+ Ok(vec)
+ }
+ }
}
#[lang = "slice_alloc"]
@@ -477,6 +527,24 @@ impl<T> [T] {
self.to_vec_in(Global)
}
+ /// Tries to copy `self` into a new `Vec`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let s = [10, 40, 30];
+ /// let x = s.try_to_vec().unwrap();
+ /// // Here, `s` and `x` can be modified independently.
+ /// ```
+ #[inline]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_to_vec(&self) -> Result<Vec<T>, TryReserveError>
+ where
+ T: Clone,
+ {
+ self.try_to_vec_in(Global)
+ }
+
/// Copies `self` into a new `Vec` with an allocator.
///
/// # Examples
@@ -501,6 +569,29 @@ impl<T> [T] {
hack::to_vec(self, alloc)
}
+ /// Tries to copy `self` into a new `Vec` with an allocator.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let s = [10, 40, 30];
+ /// let x = s.try_to_vec_in(System).unwrap();
+ /// // Here, `s` and `x` can be modified independently.
+ /// ```
+ #[inline]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_to_vec_in<A: Allocator>(&self, alloc: A) -> Result<Vec<T, A>, TryReserveError>
+ where
+ T: Clone,
+ {
+ // N.B., see the `hack` module in this file for more details.
+ hack::try_to_vec(self, alloc)
+ }
+
/// Converts `self` into a vector without clones or allocation.
///
/// The resulting vector can be converted back into a box via
diff --git a/rust/alloc/str.rs b/rust/alloc/str.rs
index 69495f31c32c..a1370c2d674c 100644
--- a/rust/alloc/str.rs
+++ b/rust/alloc/str.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! Unicode string slices.
//!
//! *[See also the `str` primitive type](str).*
@@ -36,6 +38,7 @@ use core::unicode::conversions;
use crate::borrow::ToOwned;
use crate::boxed::Box;
+use crate::collections::TryReserveError;
use crate::slice::{Concat, Join, SliceIndex};
use crate::string::String;
use crate::vec::Vec;
@@ -590,6 +593,22 @@ impl str {
// make_ascii_lowercase() preserves the UTF-8 invariant.
unsafe { String::from_utf8_unchecked(bytes) }
}
+
+ /// Tries to create a `String`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s: &str = "a";
+ /// let ss: String = s.try_to_owned().unwrap();
+ /// ```
+ #[inline]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_to_owned(&self) -> Result<String, TryReserveError> {
+ unsafe { Ok(String::from_utf8_unchecked(self.as_bytes().try_to_vec()?)) }
+ }
}
/// Converts a boxed slice of bytes to a boxed string slice without checking
diff --git a/rust/alloc/string.rs b/rust/alloc/string.rs
index 716bb4983a65..5b9780cfc11f 100644
--- a/rust/alloc/string.rs
+++ b/rust/alloc/string.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! A UTF-8–encoded, growable string.
//!
//! This module contains the [`String`] type, the [`ToString`] trait for
@@ -47,8 +49,8 @@ use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
use core::fmt;
use core::hash;
#[cfg(not(no_global_oom_handling))]
-use core::iter::FromIterator;
-use core::iter::{from_fn, FusedIterator};
+use core::iter::{from_fn, FromIterator};
+use core::iter::FusedIterator;
#[cfg(not(no_global_oom_handling))]
use core::ops::Add;
#[cfg(not(no_global_oom_handling))]
diff --git a/rust/alloc/vec/drain.rs b/rust/alloc/vec/drain.rs
index 1bff19d05c10..8116ba6dfd9e 100644
--- a/rust/alloc/vec/drain.rs
+++ b/rust/alloc/vec/drain.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
use crate::alloc::{Allocator, Global};
use core::fmt;
use core::iter::{FusedIterator, TrustedLen};
diff --git a/rust/alloc/vec/drain_filter.rs b/rust/alloc/vec/drain_filter.rs
index 3c37c92ae44b..b04fce041622 100644
--- a/rust/alloc/vec/drain_filter.rs
+++ b/rust/alloc/vec/drain_filter.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
use crate::alloc::{Allocator, Global};
use core::ptr::{self};
use core::slice::{self};
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
index f985fb78465b..11d01ac868ca 100644
--- a/rust/alloc/vec/into_iter.rs
+++ b/rust/alloc/vec/into_iter.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
use crate::alloc::{Allocator, Global};
use crate::raw_vec::RawVec;
use core::fmt;
diff --git a/rust/alloc/vec/is_zero.rs b/rust/alloc/vec/is_zero.rs
index 0efc4893c3c4..40e1e667c9fb 100644
--- a/rust/alloc/vec/is_zero.rs
+++ b/rust/alloc/vec/is_zero.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
use crate::boxed::Box;
#[rustc_specialization_trait]
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
index c29aa0fec5b8..a2b1dfca3561 100644
--- a/rust/alloc/vec/mod.rs
+++ b/rust/alloc/vec/mod.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
//! A contiguous growable array type with heap-allocated contents, written
//! `Vec<T>`.
//!
@@ -118,10 +120,8 @@ use self::spec_from_elem::SpecFromElem;
#[cfg(not(no_global_oom_handling))]
mod spec_from_elem;
-#[cfg(not(no_global_oom_handling))]
use self::set_len_on_drop::SetLenOnDrop;
-#[cfg(not(no_global_oom_handling))]
mod set_len_on_drop;
#[cfg(not(no_global_oom_handling))]
@@ -145,7 +145,8 @@ mod spec_from_iter;
#[cfg(not(no_global_oom_handling))]
use self::spec_extend::SpecExtend;
-#[cfg(not(no_global_oom_handling))]
+use self::spec_extend::TrySpecExtend;
+
mod spec_extend;
/// A contiguous growable array type, written as `Vec<T>`, short for 'vector'.
@@ -470,6 +471,49 @@ impl<T> Vec<T> {
Self::with_capacity_in(capacity, Global)
}
+ /// Tries to construct a new, empty `Vec<T>` with the specified capacity.
+ ///
+ /// The vector will be able to hold exactly `capacity` elements without
+ /// reallocating. If `capacity` is 0, the vector will not allocate.
+ ///
+ /// It is important to note that although the returned vector has the
+ /// *capacity* specified, the vector will have a zero *length*. For an
+ /// explanation of the difference between length and capacity, see
+ /// *[Capacity and reallocation]*.
+ ///
+ /// [Capacity and reallocation]: #capacity-and-reallocation
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = Vec::try_with_capacity(10).unwrap();
+ ///
+ /// // The vector contains no items, even though it has capacity for more
+ /// assert_eq!(vec.len(), 0);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // These are all done without reallocating...
+ /// for i in 0..10 {
+ /// vec.push(i);
+ /// }
+ /// assert_eq!(vec.len(), 10);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // ...but this may make the vector reallocate
+ /// vec.push(11);
+ /// assert_eq!(vec.len(), 11);
+ /// assert!(vec.capacity() >= 11);
+ ///
+ /// let mut result = Vec::try_with_capacity(usize::MAX);
+ /// assert!(result.is_err());
+ /// ```
+ #[inline]
+ #[doc(alias = "malloc")]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_with_capacity(capacity: usize) -> Result<Self, TryReserveError> {
+ Self::try_with_capacity_in(capacity, Global)
+ }
+
/// Creates a `Vec<T>` directly from the raw components of another vector.
///
/// # Safety
@@ -609,6 +653,53 @@ impl<T, A: Allocator> Vec<T, A> {
Vec { buf: RawVec::with_capacity_in(capacity, alloc), len: 0 }
}
+ /// Tries to construct a new, empty `Vec<T, A>` with the specified capacity
+ /// with the provided allocator.
+ ///
+ /// The vector will be able to hold exactly `capacity` elements without
+ /// reallocating. If `capacity` is 0, the vector will not allocate.
+ ///
+ /// It is important to note that although the returned vector has the
+ /// *capacity* specified, the vector will have a zero *length*. For an
+ /// explanation of the difference between length and capacity, see
+ /// *[Capacity and reallocation]*.
+ ///
+ /// [Capacity and reallocation]: #capacity-and-reallocation
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let mut vec = Vec::try_with_capacity_in(10, System).unwrap();
+ ///
+ /// // The vector contains no items, even though it has capacity for more
+ /// assert_eq!(vec.len(), 0);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // These are all done without reallocating...
+ /// for i in 0..10 {
+ /// vec.push(i);
+ /// }
+ /// assert_eq!(vec.len(), 10);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // ...but this may make the vector reallocate
+ /// vec.push(11);
+ /// assert_eq!(vec.len(), 11);
+ /// assert!(vec.capacity() >= 11);
+ ///
+ /// let mut result = Vec::try_with_capacity_in(usize::MAX, System);
+ /// assert!(result.is_err());
+ /// ```
+ #[inline]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_with_capacity_in(capacity: usize, alloc: A) -> Result<Self, TryReserveError> {
+ Ok(Vec { buf: RawVec::try_with_capacity_in(capacity, alloc)?, len: 0 })
+ }
+
/// Creates a `Vec<T, A>` directly from the raw components of another vector.
///
/// # Safety
@@ -940,6 +1031,33 @@ impl<T, A: Allocator> Vec<T, A> {
}
}
+ /// Tries to shrink the capacity of the vector as much as possible.
+ ///
+ /// It will drop down as close as possible to the length but the allocator
+ /// may still inform the vector that there is space for a few more elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ /// vec.extend([1, 2, 3]);
+ /// assert_eq!(vec.capacity(), 10);
+ /// vec.try_shrink_to_fit().unwrap();
+ /// assert!(vec.capacity() >= 3);
+ /// ```
+ #[doc(alias = "realloc")]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_shrink_to_fit(&mut self) -> Result<(), TryReserveError> {
+ // The capacity is never less than the length, and there's nothing to do when
+ // they are equal, so we can avoid the panic case in `RawVec::try_shrink_to_fit`
+ // by only calling it with a greater capacity.
+ if self.capacity() <= self.len {
+ return Ok(());
+ }
+
+ self.buf.try_shrink_to_fit(self.len)
+ }
+
/// Shrinks the capacity of the vector with a lower bound.
///
/// The capacity will remain at least as large as both the length
@@ -1002,6 +1120,41 @@ impl<T, A: Allocator> Vec<T, A> {
}
}
+ /// Tries to convert the vector into [`Box<[T]>`][owned slice].
+ ///
+ /// Note that this will drop any excess capacity.
+ ///
+ /// [owned slice]: Box
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let v = vec![1, 2, 3];
+ ///
+ /// let slice = v.try_into_boxed_slice().unwrap();
+ /// ```
+ ///
+ /// Any excess capacity is removed:
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ /// vec.extend([1, 2, 3]);
+ ///
+ /// assert_eq!(vec.capacity(), 10);
+ /// let slice = vec.try_into_boxed_slice().unwrap();
+ /// assert_eq!(slice.into_vec().capacity(), 3);
+ /// ```
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_into_boxed_slice(mut self) -> Result<Box<[T], A>, TryReserveError> {
+ unsafe {
+ self.try_shrink_to_fit()?;
+ let me = ManuallyDrop::new(self);
+ let buf = ptr::read(&me.buf);
+ let len = me.len();
+ Ok(buf.into_box(len).assume_init())
+ }
+ }
+
/// Shortens the vector, keeping the first `len` elements and dropping
/// the rest.
///
@@ -1735,6 +1888,29 @@ impl<T, A: Allocator> Vec<T, A> {
}
}
+ /// Tries to append an element to the back of a collection.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2];
+ /// vec.try_push(3).unwrap();
+ /// assert_eq!(vec, [1, 2, 3]);
+ /// ```
+ #[inline]
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_push(&mut self, value: T) -> Result<(), TryReserveError> {
+ if self.len == self.buf.capacity() {
+ self.buf.try_reserve_for_push(self.len)?;
+ }
+ unsafe {
+ let end = self.as_mut_ptr().add(self.len);
+ ptr::write(end, value);
+ self.len += 1;
+ }
+ Ok(())
+ }
+
/// Removes the last element from a vector and returns it, or [`None`] if it
/// is empty.
///
@@ -1799,6 +1975,17 @@ impl<T, A: Allocator> Vec<T, A> {
self.len += count;
}
+ /// Tries to append elements to `Self` from other buffer.
+ #[inline]
+ unsafe fn try_append_elements(&mut self, other: *const [T]) -> Result<(), TryReserveError> {
+ let count = unsafe { (*other).len() };
+ self.try_reserve(count)?;
+ let len = self.len();
+ unsafe { ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count) };
+ self.len += count;
+ Ok(())
+ }
+
/// Removes the specified range from the vector in bulk, returning all
/// removed elements as an iterator. If the iterator is dropped before
/// being fully consumed, it drops the remaining removed elements.
@@ -2209,6 +2396,44 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
}
}
+ /// Tries to resize the `Vec` in-place so that `len` is equal to `new_len`.
+ ///
+ /// If `new_len` is greater than `len`, the `Vec` is extended by the
+ /// difference, with each additional slot filled with `value`.
+ /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+ ///
+ /// This method requires `T` to implement [`Clone`],
+ /// in order to be able to clone the passed value.
+ /// If you need more flexibility (or want to rely on [`Default`] instead of
+ /// [`Clone`]), use [`Vec::resize_with`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec!["hello"];
+ /// vec.try_resize(3, "world").unwrap();
+ /// assert_eq!(vec, ["hello", "world", "world"]);
+ ///
+ /// let mut vec = vec![1, 2, 3, 4];
+ /// vec.try_resize(2, 0).unwrap();
+ /// assert_eq!(vec, [1, 2]);
+ ///
+ /// let mut vec = vec![42];
+ /// let result = vec.try_resize(usize::MAX, 0);
+ /// assert!(result.is_err());
+ /// ```
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_resize(&mut self, new_len: usize, value: T) -> Result<(), TryReserveError> {
+ let len = self.len();
+
+ if new_len > len {
+ self.try_extend_with(new_len - len, ExtendElement(value))
+ } else {
+ self.truncate(new_len);
+ Ok(())
+ }
+ }
+
/// Clones and appends all elements in a slice to the `Vec`.
///
/// Iterates over the slice `other`, clones each element, and then appends
@@ -2234,6 +2459,30 @@ impl<T: Clone, A: Allocator> Vec<T, A> {
self.spec_extend(other.iter())
}
+ /// Tries to clone and append all elements in a slice to the `Vec`.
+ ///
+ /// Iterates over the slice `other`, clones each element, and then appends
+ /// it to this `Vec`. The `other` slice is traversed in-order.
+ ///
+ /// Note that this function is same as [`extend`] except that it is
+ /// specialized to work with slices instead. If and when Rust gets
+ /// specialization this function will likely be deprecated (but still
+ /// available).
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1];
+ /// vec.try_extend_from_slice(&[2, 3, 4]).unwrap();
+ /// assert_eq!(vec, [1, 2, 3, 4]);
+ /// ```
+ ///
+ /// [`extend`]: Vec::extend
+ #[stable(feature = "kernel", since = "1.0.0")]
+ pub fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), TryReserveError> {
+ self.try_spec_extend(other.iter())
+ }
+
/// Copies elements from `src` range to the end of the vector.
///
/// # Panics
@@ -2328,6 +2577,36 @@ impl<T, A: Allocator> Vec<T, A> {
// len set by scope guard
}
}
+
+ /// Try to extend the vector by `n` values, using the given generator.
+ fn try_extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) -> Result<(), TryReserveError> {
+ self.try_reserve(n)?;
+
+ unsafe {
+ let mut ptr = self.as_mut_ptr().add(self.len());
+ // Use SetLenOnDrop to work around bug where compiler
+ // might not realize the store through `ptr` through self.set_len()
+ // don't alias.
+ let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+ // Write all elements except the last one
+ for _ in 1..n {
+ ptr::write(ptr, value.next());
+ ptr = ptr.offset(1);
+ // Increment the length in every step in case next() panics
+ local_len.increment_len(1);
+ }
+
+ if n > 0 {
+ // We can write the last element directly without cloning needlessly
+ ptr::write(ptr, value.last());
+ local_len.increment_len(1);
+ }
+
+ // len set by scope guard
+ Ok(())
+ }
+ }
}
impl<T: PartialEq, A: Allocator> Vec<T, A> {
@@ -2662,6 +2941,34 @@ impl<T, A: Allocator> Vec<T, A> {
}
}
+ // leaf method to which various SpecFrom/SpecExtend implementations delegate when
+ // they have no further optimizations to apply
+ fn try_extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) -> Result<(), TryReserveError> {
+ // This is the case for a general iterator.
+ //
+ // This function should be the moral equivalent of:
+ //
+ // for item in iterator {
+ // self.push(item);
+ // }
+ while let Some(element) = iterator.next() {
+ let len = self.len();
+ if len == self.capacity() {
+ let (lower, _) = iterator.size_hint();
+ self.try_reserve(lower.saturating_add(1))?;
+ }
+ unsafe {
+ ptr::write(self.as_mut_ptr().add(len), element);
+ // Since next() executes user code which can panic we have to bump the length
+ // after each step.
+ // NB can't overflow since we would have had to alloc the address space
+ self.set_len(len + 1);
+ }
+ }
+
+ Ok(())
+ }
+
/// Creates a splicing iterator that replaces the specified range in the vector
/// with the given `replace_with` iterator and yields the removed items.
/// `replace_with` does not need to be the same length as `range`.
diff --git a/rust/alloc/vec/partial_eq.rs b/rust/alloc/vec/partial_eq.rs
index 50e140961050..273e99bed488 100644
--- a/rust/alloc/vec/partial_eq.rs
+++ b/rust/alloc/vec/partial_eq.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
use crate::alloc::Allocator;
#[cfg(not(no_global_oom_handling))]
use crate::borrow::Cow;
diff --git a/rust/alloc/vec/set_len_on_drop.rs b/rust/alloc/vec/set_len_on_drop.rs
index 8b66bc812129..448bf5076a0b 100644
--- a/rust/alloc/vec/set_len_on_drop.rs
+++ b/rust/alloc/vec/set_len_on_drop.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
// Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
//
// The idea is: The length field in SetLenOnDrop is a local variable
diff --git a/rust/alloc/vec/spec_extend.rs b/rust/alloc/vec/spec_extend.rs
index c3b4534096de..729f4bb1709f 100644
--- a/rust/alloc/vec/spec_extend.rs
+++ b/rust/alloc/vec/spec_extend.rs
@@ -1,4 +1,7 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
use crate::alloc::Allocator;
+use crate::collections::{TryReserveError, TryReserveErrorKind};
use core::iter::TrustedLen;
use core::ptr::{self};
use core::slice::{self};
@@ -6,10 +9,17 @@ use core::slice::{self};
use super::{IntoIter, SetLenOnDrop, Vec};
// Specialization trait used for Vec::extend
+#[cfg(not(no_global_oom_handling))]
pub(super) trait SpecExtend<T, I> {
fn spec_extend(&mut self, iter: I);
}
+// Specialization trait used for Vec::try_extend
+pub(super) trait TrySpecExtend<T, I> {
+ fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError>;
+}
+
+#[cfg(not(no_global_oom_handling))]
impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
where
I: Iterator<Item = T>,
@@ -19,6 +29,16 @@ where
}
}
+impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
+where
+ I: Iterator<Item = T>,
+{
+ default fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError> {
+ self.try_extend_desugared(iter)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
where
I: TrustedLen<Item = T>,
@@ -57,6 +77,41 @@ where
}
}
+impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
+where
+ I: TrustedLen<Item = T>,
+{
+ default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
+ // This is the case for a TrustedLen iterator.
+ let (low, high) = iterator.size_hint();
+ if let Some(additional) = high {
+ debug_assert_eq!(
+ low,
+ additional,
+ "TrustedLen iterator's size hint is not exact: {:?}",
+ (low, high)
+ );
+ self.try_reserve(additional)?;
+ unsafe {
+ let mut ptr = self.as_mut_ptr().add(self.len());
+ let mut local_len = SetLenOnDrop::new(&mut self.len);
+ iterator.for_each(move |element| {
+ ptr::write(ptr, element);
+ ptr = ptr.offset(1);
+ // Since the loop executes user code which can panic we have to bump the pointer
+ // after each step.
+ // NB can't overflow since we would have had to alloc the address space
+ local_len.increment_len(1);
+ });
+ }
+ Ok(())
+ } else {
+ Err(TryReserveErrorKind::CapacityOverflow.into())
+ }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
unsafe {
@@ -66,6 +121,17 @@ impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
}
}
+impl<T, A: Allocator> TrySpecExtend<T, IntoIter<T>> for Vec<T, A> {
+ fn try_spec_extend(&mut self, mut iterator: IntoIter<T>) -> Result<(), TryReserveError> {
+ unsafe {
+ self.try_append_elements(iterator.as_slice() as _)?;
+ }
+ iterator.ptr = iterator.end;
+ Ok(())
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
where
I: Iterator<Item = &'a T>,
@@ -76,6 +142,17 @@ where
}
}
+impl<'a, T: 'a, I, A: Allocator + 'a> TrySpecExtend<&'a T, I> for Vec<T, A>
+where
+ I: Iterator<Item = &'a T>,
+ T: Clone,
+{
+ default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
+ self.try_spec_extend(iterator.cloned())
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
impl<'a, T: 'a, A: Allocator + 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
where
T: Copy,
@@ -85,3 +162,13 @@ where
unsafe { self.append_elements(slice) };
}
}
+
+impl<'a, T: 'a, A: Allocator + 'a> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+where
+ T: Copy,
+{
+ fn try_spec_extend(&mut self, iterator: slice::Iter<'a, T>) -> Result<(), TryReserveError> {
+ let slice = iterator.as_slice();
+ unsafe { self.try_append_elements(slice) }
+ }
+}
--
2.35.3
From: Wedson Almeida Filho <[email protected]>
This module contains the kernel APIs related to synchronisation that
have been ported or wrapped for usage by Rust code in the kernel and
is shared by all of them.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Geoffrey Thomas <[email protected]>
Signed-off-by: Geoffrey Thomas <[email protected]>
Co-developed-by: Sven Van Asbroeck <[email protected]>
Signed-off-by: Sven Van Asbroeck <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Daniel Xu <[email protected]>
Signed-off-by: Daniel Xu <[email protected]>
Co-developed-by: Hsiang-Cheng Yang <[email protected]>
Signed-off-by: Hsiang-Cheng Yang <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
include/linux/spinlock.h | 25 +-
rust/kernel/sync.rs | 161 +++++++++++
rust/kernel/sync/arc.rs | 503 ++++++++++++++++++++++++++++++++++
rust/kernel/sync/condvar.rs | 138 ++++++++++
rust/kernel/sync/guard.rs | 169 ++++++++++++
rust/kernel/sync/locked_by.rs | 111 ++++++++
rust/kernel/sync/mutex.rs | 153 +++++++++++
rust/kernel/sync/nowait.rs | 188 +++++++++++++
rust/kernel/sync/revocable.rs | 250 +++++++++++++++++
rust/kernel/sync/rwsem.rs | 197 +++++++++++++
rust/kernel/sync/seqlock.rs | 202 ++++++++++++++
rust/kernel/sync/smutex.rs | 295 ++++++++++++++++++++
rust/kernel/sync/spinlock.rs | 360 ++++++++++++++++++++++++
13 files changed, 2745 insertions(+), 7 deletions(-)
create mode 100644 rust/kernel/sync.rs
create mode 100644 rust/kernel/sync/arc.rs
create mode 100644 rust/kernel/sync/condvar.rs
create mode 100644 rust/kernel/sync/guard.rs
create mode 100644 rust/kernel/sync/locked_by.rs
create mode 100644 rust/kernel/sync/mutex.rs
create mode 100644 rust/kernel/sync/nowait.rs
create mode 100644 rust/kernel/sync/revocable.rs
create mode 100644 rust/kernel/sync/rwsem.rs
create mode 100644 rust/kernel/sync/seqlock.rs
create mode 100644 rust/kernel/sync/smutex.rs
create mode 100644 rust/kernel/sync/spinlock.rs
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 5c0c5174155d..cdcbf9d9c70c 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -99,11 +99,17 @@
extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
struct lock_class_key *key, short inner);
+static inline void _raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+ struct lock_class_key *key)
+{
+ __raw_spin_lock_init(lock, name, key, LD_WAIT_SPIN);
+}
+
# define raw_spin_lock_init(lock) \
do { \
static struct lock_class_key __key; \
\
- __raw_spin_lock_init((lock), #lock, &__key, LD_WAIT_SPIN); \
+ _raw_spin_lock_init((lock), #lock, &__key); \
} while (0)
#else
@@ -326,12 +332,17 @@ static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
#ifdef CONFIG_DEBUG_SPINLOCK
-# define spin_lock_init(lock) \
-do { \
- static struct lock_class_key __key; \
- \
- __raw_spin_lock_init(spinlock_check(lock), \
- #lock, &__key, LD_WAIT_CONFIG); \
+static inline void __spin_lock_init(spinlock_t *lock, const char *name,
+ struct lock_class_key *key)
+{
+ __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
+}
+
+# define spin_lock_init(lock) \
+do { \
+ static struct lock_class_key __key; \
+ \
+ __spin_lock_init(lock, #lock, &__key); \
} while (0)
#else
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
new file mode 100644
index 000000000000..66536fe2ba18
--- /dev/null
+++ b/rust/kernel/sync.rs
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Synchronisation primitives.
+//!
+//! This module contains the kernel APIs related to synchronisation that have been ported or
+//! wrapped for usage by Rust code in the kernel and is shared by all of them.
+//!
+//! # Example
+//!
+//! ```
+//! # use kernel::mutex_init;
+//! # use kernel::sync::Mutex;
+//! # use alloc::boxed::Box;
+//! # use core::pin::Pin;
+//! // SAFETY: `init` is called below.
+//! let mut data = Pin::from(Box::try_new(unsafe { Mutex::new(10) }).unwrap());
+//! mutex_init!(data.as_mut(), "test::data");
+//!
+//! assert_eq!(*data.lock(), 10);
+//! *data.lock() = 20;
+//! assert_eq!(*data.lock(), 20);
+//! ```
+
+use crate::{bindings, str::CStr};
+use core::pin::Pin;
+
+mod arc;
+mod condvar;
+mod guard;
+mod locked_by;
+mod mutex;
+mod nowait;
+mod revocable;
+mod rwsem;
+mod seqlock;
+pub mod smutex;
+mod spinlock;
+
+pub use arc::{Ref, RefBorrow, UniqueRef};
+pub use condvar::CondVar;
+pub use guard::{Guard, Lock, LockFactory, LockInfo, LockIniter, ReadLock, WriteLock};
+pub use locked_by::LockedBy;
+pub use mutex::{Mutex, RevocableMutex, RevocableMutexGuard};
+pub use nowait::{NoWaitLock, NoWaitLockGuard};
+pub use revocable::{Revocable, RevocableGuard};
+pub use rwsem::{RevocableRwSemaphore, RevocableRwSemaphoreGuard, RwSemaphore};
+pub use seqlock::{SeqLock, SeqLockReadGuard};
+pub use spinlock::{RawSpinLock, SpinLock};
+
+/// Safely initialises an object that has an `init` function that takes a name and a lock class as
+/// arguments, examples of these are [`Mutex`] and [`SpinLock`]. Each of them also provides a more
+/// specialised name that uses this macro.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! init_with_lockdep {
+ ($obj:expr, $name:expr) => {{
+ static mut CLASS1: core::mem::MaybeUninit<$crate::bindings::lock_class_key> =
+ core::mem::MaybeUninit::uninit();
+ static mut CLASS2: core::mem::MaybeUninit<$crate::bindings::lock_class_key> =
+ core::mem::MaybeUninit::uninit();
+ let obj = $obj;
+ let name = $crate::c_str!($name);
+ // SAFETY: `CLASS1` and `CLASS2` are never used by Rust code directly; the C portion of the
+ // kernel may change it though.
+ #[allow(unused_unsafe)]
+ unsafe {
+ $crate::sync::NeedsLockClass::init(obj, name, CLASS1.as_mut_ptr(), CLASS2.as_mut_ptr())
+ };
+ }};
+}
+
+/// A trait for types that need a lock class during initialisation.
+///
+/// Implementers of this trait benefit from the [`init_with_lockdep`] macro that generates a new
+/// class for each initialisation call site.
+pub trait NeedsLockClass {
+ /// Initialises the type instance so that it can be safely used.
+ ///
+ /// Callers are encouraged to use the [`init_with_lockdep`] macro as it automatically creates a
+ /// new lock class on each usage.
+ ///
+ /// # Safety
+ ///
+ /// `key1` and `key2` must point to valid memory locations and remain valid until `self` is
+ /// dropped.
+ unsafe fn init(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key1: *mut bindings::lock_class_key,
+ key2: *mut bindings::lock_class_key,
+ );
+}
+
+/// Automatically initialises static instances of synchronisation primitives.
+///
+/// The syntax resembles that of regular static variables, except that the value assigned is that
+/// of the protected type (if one exists). In the examples below, all primitives except for
+/// [`CondVar`] require the inner value to be supplied.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::{init_static_sync, sync::{CondVar, Mutex, RevocableMutex, SpinLock}};
+/// struct Test {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// init_static_sync! {
+/// static A: Mutex<Test> = Test { a: 10, b: 20 };
+///
+/// /// Documentation for `B`.
+/// pub static B: Mutex<u32> = 0;
+///
+/// pub(crate) static C: SpinLock<Test> = Test { a: 10, b: 20 };
+/// static D: CondVar;
+///
+/// static E: RevocableMutex<Test> = Test { a: 30, b: 40 };
+/// }
+/// ```
+#[macro_export]
+macro_rules! init_static_sync {
+ ($($(#[$outer:meta])* $v:vis static $id:ident : $t:ty $(= $value:expr)?;)*) => {
+ $(
+ $(#[$outer])*
+ $v static $id: $t = {
+ #[link_section = ".init_array"]
+ #[used]
+ static TMP: extern "C" fn() = {
+ extern "C" fn constructor() {
+ // SAFETY: This locally-defined function is only called from a constructor,
+ // which guarantees that `$id` is not accessible from other threads
+ // concurrently.
+ #[allow(clippy::cast_ref_to_mut)]
+ let mutable = unsafe { &mut *(&$id as *const _ as *mut $t) };
+ // SAFETY: It's a shared static, so it cannot move.
+ let pinned = unsafe { core::pin::Pin::new_unchecked(mutable) };
+ $crate::init_with_lockdep!(pinned, stringify!($id));
+ }
+ constructor
+ };
+ $crate::init_static_sync!(@call_new $t, $($value)?)
+ };
+ )*
+ };
+ (@call_new $t:ty, $value:expr) => {{
+ let v = $value;
+ // SAFETY: the initialisation function is called by the constructor above.
+ unsafe { <$t>::new(v) }
+ }};
+ (@call_new $t:ty,) => {
+ // SAFETY: the initialisation function is called by the constructor above.
+ unsafe { <$t>::new() }
+ };
+}
+
+/// Reschedules the caller's task if needed.
+pub fn cond_resched() -> bool {
+ // SAFETY: No arguments, reschedules `current` if needed.
+ unsafe { bindings::cond_resched() != 0 }
+}
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
new file mode 100644
index 000000000000..056d2bae632a
--- /dev/null
+++ b/rust/kernel/sync/arc.rs
@@ -0,0 +1,503 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A reference-counted pointer.
+//!
+//! This module implements a way for users to create reference-counted objects and pointers to
+//! them. Such a pointer automatically increments and decrements the count, and drops the
+//! underlying object when it reaches zero. It is also safe to use concurrently from multiple
+//! threads.
+//!
+//! It is different from the standard library's [`Arc`] in a few ways:
+//! 1. It is backed by the kernel's `refcount_t` type.
+//! 2. It does not support weak references, which allows it to be half the size.
+//! 3. It saturates the reference count instead of aborting when it goes over a threshold.
+//! 4. It does not provide a `get_mut` method, so the ref counted object is pinned.
+//!
+//! [`Arc`]: https://doc.rust-lang.org/std/sync/struct.Arc.html
+
+use crate::{bindings, error::code::*, Error, Opaque, Result};
+use alloc::{
+ alloc::{alloc, dealloc},
+ vec::Vec,
+};
+use core::{
+ alloc::Layout,
+ convert::{AsRef, TryFrom},
+ marker::{PhantomData, Unsize},
+ mem::{ManuallyDrop, MaybeUninit},
+ ops::{Deref, DerefMut},
+ pin::Pin,
+ ptr::{self, NonNull},
+};
+
+/// A reference-counted pointer to an instance of `T`.
+///
+/// The reference count is incremented when new instances of [`Ref`] are created, and decremented
+/// when they are dropped. When the count reaches zero, the underlying `T` is also dropped.
+///
+/// # Invariants
+///
+/// The reference count on an instance of [`Ref`] is always non-zero.
+/// The object pointed to by [`Ref`] is always pinned.
+pub struct Ref<T: ?Sized> {
+ ptr: NonNull<RefInner<T>>,
+ _p: PhantomData<RefInner<T>>,
+}
+
+#[repr(C)]
+struct RefInner<T: ?Sized> {
+ refcount: Opaque<bindings::refcount_t>,
+ data: T,
+}
+
+// This is to allow [`Ref`] (and variants) to be used as the type of `self`.
+impl<T: ?Sized> core::ops::Receiver for Ref<T> {}
+
+// This is to allow [`RefBorrow`] (and variants) to be used as the type of `self`.
+impl<T: ?Sized> core::ops::Receiver for RefBorrow<'_, T> {}
+
+// This is to allow coercion from `Ref<T>` to `Ref<U>` if `T` can be converted to the
+// dynamically-sized type (DST) `U`.
+impl<T: ?Sized + Unsize<U>, U: ?Sized> core::ops::CoerceUnsized<Ref<U>> for Ref<T> {}
+
+// This is to allow `Ref<U>` to be dispatched on when `Ref<T>` can be coerced into `Ref<U>`.
+impl<T: ?Sized + Unsize<U>, U: ?Sized> core::ops::DispatchFromDyn<Ref<U>> for Ref<T> {}
+
+// SAFETY: It is safe to send `Ref<T>` to another thread when the underlying `T` is `Sync` because
+// it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs
+// `T` to be `Send` because any thread that has a `Ref<T>` may ultimately access `T` directly, for
+// example, when the reference count reaches zero and `T` is dropped.
+unsafe impl<T: ?Sized + Sync + Send> Send for Ref<T> {}
+
+// SAFETY: It is safe to send `&Ref<T>` to another thread when the underlying `T` is `Sync` for
+// the same reason as above. `T` needs to be `Send` as well because a thread can clone a `&Ref<T>`
+// into a `Ref<T>`, which may lead to `T` being accessed by the same reasoning as above.
+unsafe impl<T: ?Sized + Sync + Send> Sync for Ref<T> {}
+
+impl<T> Ref<T> {
+ /// Constructs a new reference counted instance of `T`.
+ pub fn try_new(contents: T) -> Result<Self> {
+ let layout = Layout::new::<RefInner<T>>();
+ // SAFETY: The layout size is guaranteed to be non-zero because `RefInner` contains the
+ // reference count.
+ let inner = NonNull::new(unsafe { alloc(layout) })
+ .ok_or(ENOMEM)?
+ .cast::<RefInner<T>>();
+
+ // INVARIANT: The refcount is initialised to a non-zero value.
+ let value = RefInner {
+ // SAFETY: Just an FFI call that returns a `refcount_t` initialised to 1.
+ refcount: Opaque::new(unsafe { bindings::REFCOUNT_INIT(1) }),
+ data: contents,
+ };
+ // SAFETY: `inner` is writable and properly aligned.
+ unsafe { inner.as_ptr().write(value) };
+
+ // SAFETY: We just created `inner` with a reference count of 1, which is owned by the new
+ // `Ref` object.
+ Ok(unsafe { Self::from_inner(inner) })
+ }
+
+ /// Deconstructs a [`Ref`] object into a `usize`.
+ ///
+ /// It can be reconstructed once via [`Ref::from_usize`].
+ pub fn into_usize(obj: Self) -> usize {
+ ManuallyDrop::new(obj).ptr.as_ptr() as _
+ }
+
+ /// Borrows a [`Ref`] instance previously deconstructed via [`Ref::into_usize`].
+ ///
+ /// # Safety
+ ///
+ /// `encoded` must have been returned by a previous call to [`Ref::into_usize`]. Additionally,
+ /// [`Ref::from_usize`] can only be called after *all* instances of [`RefBorrow`] have been
+ /// dropped.
+ pub unsafe fn borrow_usize<'a>(encoded: usize) -> RefBorrow<'a, T> {
+ // SAFETY: By the safety requirement of this function, we know that `encoded` came from
+ // a previous call to `Ref::into_usize`.
+ let inner = NonNull::new(encoded as *mut RefInner<T>).unwrap();
+
+ // SAFETY: The safety requirements ensure that the object remains alive for the lifetime of
+ // the returned value. There is no way to create mutable references to the object.
+ unsafe { RefBorrow::new(inner) }
+ }
+
+ /// Recreates a [`Ref`] instance previously deconstructed via [`Ref::into_usize`].
+ ///
+ /// # Safety
+ ///
+ /// `encoded` must have been returned by a previous call to [`Ref::into_usize`]. Additionally,
+ /// it can only be called once for each previous call to [`Ref::into_usize`].
+ pub unsafe fn from_usize(encoded: usize) -> Self {
+ // SAFETY: By the safety invariants we know that `encoded` came from `Ref::into_usize`, so
+ // the reference count held then will be owned by the new `Ref` object.
+ unsafe { Self::from_inner(NonNull::new(encoded as _).unwrap()) }
+ }
+}
+
+impl<T: ?Sized> Ref<T> {
+ /// Constructs a new [`Ref`] from an existing [`RefInner`].
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `inner` points to a valid location and has a non-zero reference
+ /// count, one of which will be owned by the new [`Ref`] instance.
+ unsafe fn from_inner(inner: NonNull<RefInner<T>>) -> Self {
+ // INVARIANT: By the safety requirements, the invariants hold.
+ Ref {
+ ptr: inner,
+ _p: PhantomData,
+ }
+ }
+
+ /// Determines if two reference-counted pointers point to the same underlying instance of `T`.
+ pub fn ptr_eq(a: &Self, b: &Self) -> bool {
+ ptr::eq(a.ptr.as_ptr(), b.ptr.as_ptr())
+ }
+
+ /// Deconstructs a [`Ref`] object into a raw pointer.
+ ///
+ /// It can be reconstructed once via [`Ref::from_raw`].
+ pub fn into_raw(obj: Self) -> *const T {
+ let ret = &*obj as *const T;
+ core::mem::forget(obj);
+ ret
+ }
+
+ /// Recreates a [`Ref`] instance previously deconstructed via [`Ref::into_raw`].
+ ///
+ /// This code relies on the `repr(C)` layout of structs as described in
+ /// <https://doc.rust-lang.org/reference/type-layout.html#reprc-structs>.
+ ///
+ /// # Safety
+ ///
+ /// `ptr` must have been returned by a previous call to [`Ref::into_raw`]. Additionally, it
+ /// can only be called once for each previous call to [`Ref::into_raw`].
+ pub unsafe fn from_raw(ptr: *const T) -> Self {
+ // SAFETY: The safety requirement ensures that the pointer is valid.
+ let align = core::mem::align_of_val(unsafe { &*ptr });
+ let offset = Layout::new::<RefInner<()>>()
+ .align_to(align)
+ .unwrap()
+ .pad_to_align()
+ .size();
+ // SAFETY: The pointer is in bounds because by the safety requirements `ptr` came from
+ // `Ref::into_raw`, so it is a pointer `offset` bytes from the beginning of the allocation.
+ let data = unsafe { (ptr as *const u8).sub(offset) };
+ let metadata = ptr::metadata(ptr as *const RefInner<T>);
+ let ptr = ptr::from_raw_parts_mut(data as _, metadata);
+ // SAFETY: By the safety requirements we know that `ptr` came from `Ref::into_raw`, so the
+ // reference count held then will be owned by the new `Ref` object.
+ unsafe { Self::from_inner(NonNull::new(ptr).unwrap()) }
+ }
+
+ /// Returns a [`RefBorrow`] from the given [`Ref`].
+ ///
+ /// This is useful when the argument of a function call is a [`RefBorrow`] (e.g., in a method
+ /// receiver), but we have a [`Ref`] instead. Getting a [`RefBorrow`] is free when optimised.
+ #[inline]
+ pub fn as_ref_borrow(&self) -> RefBorrow<'_, T> {
+ // SAFETY: The constraint that lifetime of the shared reference must outlive that of
+ // the returned `RefBorrow` ensures that the object remains alive.
+ unsafe { RefBorrow::new(self.ptr) }
+ }
+}
+
+impl<T: ?Sized> Deref for Ref<T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is
+ // safe to dereference it.
+ unsafe { &self.ptr.as_ref().data }
+ }
+}
+
+impl<T: ?Sized> Clone for Ref<T> {
+ fn clone(&self) -> Self {
+ // INVARIANT: C `refcount_inc` saturates the refcount, so it cannot overflow to zero.
+ // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is
+ // safe to increment the refcount.
+ unsafe { bindings::refcount_inc(self.ptr.as_ref().refcount.get()) };
+
+ // SAFETY: We just incremented the refcount. This increment is now owned by the new `Ref`.
+ unsafe { Self::from_inner(self.ptr) }
+ }
+}
+
+impl<T: ?Sized> AsRef<T> for Ref<T> {
+ fn as_ref(&self) -> &T {
+ // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is
+ // safe to dereference it.
+ unsafe { &self.ptr.as_ref().data }
+ }
+}
+
+impl<T: ?Sized> Drop for Ref<T> {
+ fn drop(&mut self) {
+ // SAFETY: By the type invariant, there is necessarily a reference to the object. We cannot
+ // touch `refcount` after it's decremented to a non-zero value because another thread/CPU
+ // may concurrently decrement it to zero and free it. It is ok to have a raw pointer to
+ // freed/invalid memory as long as it is never dereferenced.
+ let refcount = unsafe { self.ptr.as_ref() }.refcount.get();
+
+ // INVARIANT: If the refcount reaches zero, there are no other instances of `Ref`, and
+ // this instance is being dropped, so the broken invariant is not observable.
+ // SAFETY: Also by the type invariant, we are allowed to decrement the refcount.
+ let is_zero = unsafe { bindings::refcount_dec_and_test(refcount) };
+ if is_zero {
+ // The count reached zero, we must free the memory.
+
+ // SAFETY: This thread holds the only remaining reference to `self`, so it is safe to
+ // get a mutable reference to it.
+ let inner = unsafe { self.ptr.as_mut() };
+ let layout = Layout::for_value(inner);
+ // SAFETY: The value stored in inner is valid.
+ unsafe { core::ptr::drop_in_place(inner) };
+ // SAFETY: The pointer was initialised from the result of a call to `alloc`.
+ unsafe { dealloc(self.ptr.cast().as_ptr(), layout) };
+ }
+ }
+}
+
+impl<T> TryFrom<Vec<T>> for Ref<[T]> {
+ type Error = Error;
+
+ fn try_from(mut v: Vec<T>) -> Result<Self> {
+ let value_layout = Layout::array::<T>(v.len())?;
+ let layout = Layout::new::<RefInner<()>>()
+ .extend(value_layout)?
+ .0
+ .pad_to_align();
+ // SAFETY: The layout size is guaranteed to be non-zero because `RefInner` contains the
+ // reference count.
+ let ptr = NonNull::new(unsafe { alloc(layout) }).ok_or(ENOMEM)?;
+ let inner =
+ core::ptr::slice_from_raw_parts_mut(ptr.as_ptr() as _, v.len()) as *mut RefInner<[T]>;
+
+ // SAFETY: Just an FFI call that returns a `refcount_t` initialised to 1.
+ let count = Opaque::new(unsafe { bindings::REFCOUNT_INIT(1) });
+ // SAFETY: `inner.refcount` is writable and properly aligned.
+ unsafe { core::ptr::addr_of_mut!((*inner).refcount).write(count) };
+ // SAFETY: The contents of `v` as readable and properly aligned; `inner.data` is writable
+ // and properly aligned. There is no overlap between the two because `inner` is a new
+ // allocation.
+ unsafe {
+ core::ptr::copy_nonoverlapping(
+ v.as_ptr(),
+ core::ptr::addr_of_mut!((*inner).data) as *mut [T] as *mut T,
+ v.len(),
+ )
+ };
+ // SAFETY: We're setting the new length to zero, so it is <= to capacity, and old_len..0 is
+ // an empty range (so satisfies vacuously the requirement of being initialised).
+ unsafe { v.set_len(0) };
+ // SAFETY: We just created `inner` with a reference count of 1, which is owned by the new
+ // `Ref` object.
+ Ok(unsafe { Self::from_inner(NonNull::new(inner).unwrap()) })
+ }
+}
+
+impl<T: ?Sized> From<UniqueRef<T>> for Ref<T> {
+ fn from(item: UniqueRef<T>) -> Self {
+ item.inner
+ }
+}
+
+impl<T: ?Sized> From<UniqueRef<T>> for Pin<UniqueRef<T>> {
+ fn from(obj: UniqueRef<T>) -> Self {
+ // SAFETY: It is not possible to move/replace `T` inside a `Pin<UniqueRef<T>>` (unless `T`
+ // is `Unpin`), so it is ok to convert it to `Pin<UniqueRef<T>>`.
+ unsafe { Pin::new_unchecked(obj) }
+ }
+}
+
+impl<T: ?Sized> From<Pin<UniqueRef<T>>> for Ref<T> {
+ fn from(item: Pin<UniqueRef<T>>) -> Self {
+ // SAFETY: The type invariants of `Ref` guarantee that the data is pinned.
+ unsafe { Pin::into_inner_unchecked(item).inner }
+ }
+}
+
+/// A borrowed [`Ref`] with manually-managed lifetime.
+///
+/// # Invariants
+///
+/// There are no mutable references to the underlying [`Ref`], and it remains valid for the lifetime
+/// of the [`RefBorrow`] instance.
+pub struct RefBorrow<'a, T: ?Sized + 'a> {
+ inner: NonNull<RefInner<T>>,
+ _p: PhantomData<&'a ()>,
+}
+
+impl<T: ?Sized> Clone for RefBorrow<'_, T> {
+ fn clone(&self) -> Self {
+ *self
+ }
+}
+
+impl<T: ?Sized> Copy for RefBorrow<'_, T> {}
+
+impl<T: ?Sized> RefBorrow<'_, T> {
+ /// Creates a new [`RefBorrow`] instance.
+ ///
+ /// # Safety
+ ///
+ /// Callers must ensure the following for the lifetime of the returned [`RefBorrow`] instance:
+ /// 1. That `obj` remains valid;
+ /// 2. That no mutable references to `obj` are created.
+ unsafe fn new(inner: NonNull<RefInner<T>>) -> Self {
+ // INVARIANT: The safety requirements guarantee the invariants.
+ Self {
+ inner,
+ _p: PhantomData,
+ }
+ }
+}
+
+impl<T: ?Sized> From<RefBorrow<'_, T>> for Ref<T> {
+ fn from(b: RefBorrow<'_, T>) -> Self {
+ // SAFETY: The existence of `b` guarantees that the refcount is non-zero. `ManuallyDrop`
+ // guarantees that `drop` isn't called, so it's ok that the temporary `Ref` doesn't own the
+ // increment.
+ ManuallyDrop::new(unsafe { Ref::from_inner(b.inner) })
+ .deref()
+ .clone()
+ }
+}
+
+impl<T: ?Sized> Deref for RefBorrow<'_, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: By the type invariant, the underlying object is still alive with no mutable
+ // references to it, so it is safe to create a shared reference.
+ unsafe { &self.inner.as_ref().data }
+ }
+}
+
+/// A refcounted object that is known to have a refcount of 1.
+///
+/// It is mutable and can be converted to a [`Ref`] so that it can be shared.
+///
+/// # Invariants
+///
+/// `inner` always has a reference count of 1.
+///
+/// # Examples
+///
+/// In the following example, we make changes to the inner object before turning it into a
+/// `Ref<Test>` object (after which point, it cannot be mutated directly). Note that `x.into()`
+/// cannot fail.
+///
+/// ```
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn test() -> Result<Ref<Example>> {
+/// let mut x = UniqueRef::try_new(Example { a: 10, b: 20 })?;
+/// x.a += 1;
+/// x.b += 1;
+/// Ok(x.into())
+/// }
+///
+/// # test();
+/// ```
+///
+/// In the following example we first allocate memory for a ref-counted `Example` but we don't
+/// initialise it on allocation. We do initialise it later with a call to [`UniqueRef::write`],
+/// followed by a conversion to `Ref<Example>`. This is particularly useful when allocation happens
+/// in one context (e.g., sleepable) and initialisation in another (e.g., atomic):
+///
+/// ```
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn test() -> Result<Ref<Example>> {
+/// let x = UniqueRef::try_new_uninit()?;
+/// Ok(x.write(Example { a: 10, b: 20 }).into())
+/// }
+///
+/// # test();
+/// ```
+///
+/// In the last example below, the caller gets a pinned instance of `Example` while converting to
+/// `Ref<Example>`; this is useful in scenarios where one needs a pinned reference during
+/// initialisation, for example, when initialising fields that are wrapped in locks.
+///
+/// ```
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn test() -> Result<Ref<Example>> {
+/// let mut pinned = Pin::from(UniqueRef::try_new(Example { a: 10, b: 20 })?);
+/// // We can modify `pinned` because it is `Unpin`.
+/// pinned.as_mut().a += 1;
+/// Ok(pinned.into())
+/// }
+///
+/// # test();
+/// ```
+pub struct UniqueRef<T: ?Sized> {
+ inner: Ref<T>,
+}
+
+impl<T> UniqueRef<T> {
+ /// Tries to allocate a new [`UniqueRef`] instance.
+ pub fn try_new(value: T) -> Result<Self> {
+ Ok(Self {
+ // INVARIANT: The newly-created object has a ref-count of 1.
+ inner: Ref::try_new(value)?,
+ })
+ }
+
+ /// Tries to allocate a new [`UniqueRef`] instance whose contents are not initialised yet.
+ pub fn try_new_uninit() -> Result<UniqueRef<MaybeUninit<T>>> {
+ Ok(UniqueRef::<MaybeUninit<T>> {
+ // INVARIANT: The newly-created object has a ref-count of 1.
+ inner: Ref::try_new(MaybeUninit::uninit())?,
+ })
+ }
+}
+
+impl<T> UniqueRef<MaybeUninit<T>> {
+ /// Converts a `UniqueRef<MaybeUninit<T>>` into a `UniqueRef<T>` by writing a value into it.
+ pub fn write(mut self, value: T) -> UniqueRef<T> {
+ self.deref_mut().write(value);
+ let inner = ManuallyDrop::new(self).inner.ptr;
+ UniqueRef {
+ // SAFETY: The new `Ref` is taking over `ptr` from `self.inner` (which won't be
+ // dropped). The types are compatible because `MaybeUninit<T>` is compatible with `T`.
+ inner: unsafe { Ref::from_inner(inner.cast()) },
+ }
+ }
+}
+
+impl<T: ?Sized> Deref for UniqueRef<T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ self.inner.deref()
+ }
+}
+
+impl<T: ?Sized> DerefMut for UniqueRef<T> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ // SAFETY: By the `Ref` type invariant, there is necessarily a reference to the object, so
+ // it is safe to dereference it. Additionally, we know there is only one reference when
+ // it's inside a `UniqueRef`, so it is safe to get a mutable reference.
+ unsafe { &mut self.inner.ptr.as_mut().data }
+ }
+}
diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs
new file mode 100644
index 000000000000..7f8aa1c55a19
--- /dev/null
+++ b/rust/kernel/sync/condvar.rs
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A condition variable.
+//!
+//! This module allows Rust code to use the kernel's [`struct wait_queue_head`] as a condition
+//! variable.
+
+use super::{Guard, Lock, LockInfo, NeedsLockClass};
+use crate::{bindings, str::CStr, task::Task, Opaque};
+use core::{marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`CondVar`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! condvar_init {
+ ($condvar:expr, $name:literal) => {
+ $crate::init_with_lockdep!($condvar, $name)
+ };
+}
+
+// TODO: `bindgen` is not generating this constant. Figure out why.
+const POLLFREE: u32 = 0x4000;
+
+/// Exposes the kernel's [`struct wait_queue_head`] as a condition variable. It allows the caller to
+/// atomically release the given lock and go to sleep. It reacquires the lock when it wakes up. And
+/// it wakes up when notified by another thread (via [`CondVar::notify_one`] or
+/// [`CondVar::notify_all`]) or because the thread received a signal.
+///
+/// [`struct wait_queue_head`]: ../../../include/linux/wait.h
+pub struct CondVar {
+ pub(crate) wait_list: Opaque<bindings::wait_queue_head>,
+
+ /// A condvar needs to be pinned because it contains a [`struct list_head`] that is
+ /// self-referential, so it cannot be safely moved once it is initialised.
+ _pin: PhantomPinned,
+}
+
+// SAFETY: `CondVar` only uses a `struct wait_queue_head`, which is safe to use on any thread.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl Send for CondVar {}
+
+// SAFETY: `CondVar` only uses a `struct wait_queue_head`, which is safe to use on multiple threads
+// concurrently.
+unsafe impl Sync for CondVar {}
+
+impl CondVar {
+ /// Constructs a new conditional variable.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call `CondVar::init` before using the conditional variable.
+ pub const unsafe fn new() -> Self {
+ Self {
+ wait_list: Opaque::uninit(),
+ _pin: PhantomPinned,
+ }
+ }
+
+ /// Atomically releases the given lock (whose ownership is proven by the guard) and puts the
+ /// thread to sleep. It wakes up when notified by [`CondVar::notify_one`] or
+ /// [`CondVar::notify_all`], or when the thread receives a signal.
+ ///
+ /// Returns whether there is a signal pending.
+ #[must_use = "wait returns if a signal is pending, so the caller must check the return value"]
+ pub fn wait<L: Lock<I>, I: LockInfo>(&self, guard: &mut Guard<'_, L, I>) -> bool {
+ let lock = guard.lock;
+ let wait = Opaque::<bindings::wait_queue_entry>::uninit();
+
+ // SAFETY: `wait` points to valid memory.
+ unsafe { bindings::init_wait(wait.get()) };
+
+ // SAFETY: Both `wait` and `wait_list` point to valid memory.
+ unsafe {
+ bindings::prepare_to_wait_exclusive(
+ self.wait_list.get(),
+ wait.get(),
+ bindings::TASK_INTERRUPTIBLE as _,
+ )
+ };
+
+ // SAFETY: The guard is evidence that the caller owns the lock.
+ unsafe { lock.unlock(&mut guard.context) };
+
+ // SAFETY: No arguments, switches to another thread.
+ unsafe { bindings::schedule() };
+
+ guard.context = lock.lock_noguard();
+
+ // SAFETY: Both `wait` and `wait_list` point to valid memory.
+ unsafe { bindings::finish_wait(self.wait_list.get(), wait.get()) };
+
+ Task::current().signal_pending()
+ }
+
+ /// Calls the kernel function to notify the appropriate number of threads with the given flags.
+ fn notify(&self, count: i32, flags: u32) {
+ // SAFETY: `wait_list` points to valid memory.
+ unsafe {
+ bindings::__wake_up(
+ self.wait_list.get(),
+ bindings::TASK_NORMAL,
+ count,
+ flags as _,
+ )
+ };
+ }
+
+ /// Wakes a single waiter up, if any. This is not 'sticky' in the sense that if no thread is
+ /// waiting, the notification is lost completely (as opposed to automatically waking up the
+ /// next waiter).
+ pub fn notify_one(&self) {
+ self.notify(1, 0);
+ }
+
+ /// Wakes all waiters up, if any. This is not 'sticky' in the sense that if no thread is
+ /// waiting, the notification is lost completely (as opposed to automatically waking up the
+ /// next waiter).
+ pub fn notify_all(&self) {
+ self.notify(0, 0);
+ }
+
+ /// Wakes all waiters up. If they were added by `epoll`, they are also removed from the list of
+ /// waiters. This is useful when cleaning up a condition variable that may be waited on by
+ /// threads that use `epoll`.
+ pub fn free_waiters(&self) {
+ self.notify(1, bindings::POLLHUP | POLLFREE);
+ }
+}
+
+impl NeedsLockClass for CondVar {
+ unsafe fn init(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ _: *mut bindings::lock_class_key,
+ ) {
+ unsafe { bindings::__init_waitqueue_head(self.wait_list.get(), name.as_char_ptr(), key) };
+ }
+}
diff --git a/rust/kernel/sync/guard.rs b/rust/kernel/sync/guard.rs
new file mode 100644
index 000000000000..a552412110ff
--- /dev/null
+++ b/rust/kernel/sync/guard.rs
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A generic lock guard and trait.
+//!
+//! This module contains a lock guard that can be used with any locking primitive that implements
+//! the ([`Lock`]) trait. It also contains the definition of the trait, which can be leveraged by
+//! other constructs to work on generic locking primitives.
+
+use super::NeedsLockClass;
+use crate::{bindings, str::CStr, Bool, False, True};
+use core::pin::Pin;
+
+/// Allows mutual exclusion primitives that implement the [`Lock`] trait to automatically unlock
+/// when a guard goes out of scope. It also provides a safe and convenient way to access the data
+/// protected by the lock.
+#[must_use = "the lock unlocks immediately when the guard is unused"]
+pub struct Guard<'a, L: Lock<I> + ?Sized, I: LockInfo = WriteLock> {
+ pub(crate) lock: &'a L,
+ pub(crate) context: L::GuardContext,
+}
+
+// SAFETY: `Guard` is sync when the data protected by the lock is also sync. This is more
+// conservative than the default compiler implementation; more details can be found on
+// https://github.com/rust-lang/rust/issues/41622 -- it refers to `MutexGuard` from the standard
+// library.
+unsafe impl<L, I> Sync for Guard<'_, L, I>
+where
+ L: Lock<I> + ?Sized,
+ L::Inner: Sync,
+ I: LockInfo,
+{
+}
+
+impl<L: Lock<I> + ?Sized, I: LockInfo> core::ops::Deref for Guard<'_, L, I> {
+ type Target = L::Inner;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: The caller owns the lock, so it is safe to deref the protected data.
+ unsafe { &*self.lock.locked_data().get() }
+ }
+}
+
+impl<L: Lock<I> + ?Sized, I: LockInfo<Writable = True>> core::ops::DerefMut for Guard<'_, L, I> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ // SAFETY: The caller owns the lock, so it is safe to deref the protected data.
+ unsafe { &mut *self.lock.locked_data().get() }
+ }
+}
+
+impl<L: Lock<I> + ?Sized, I: LockInfo> Drop for Guard<'_, L, I> {
+ fn drop(&mut self) {
+ // SAFETY: The caller owns the lock, so it is safe to unlock it.
+ unsafe { self.lock.unlock(&mut self.context) };
+ }
+}
+
+impl<'a, L: Lock<I> + ?Sized, I: LockInfo> Guard<'a, L, I> {
+ /// Constructs a new immutable lock guard.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that it owns the lock.
+ pub(crate) unsafe fn new(lock: &'a L, context: L::GuardContext) -> Self {
+ Self { lock, context }
+ }
+}
+
+/// Specifies properties of a lock.
+pub trait LockInfo {
+ /// Determines if the data protected by a lock is writable.
+ type Writable: Bool;
+}
+
+/// A marker for locks that only allow reading.
+pub struct ReadLock;
+impl LockInfo for ReadLock {
+ type Writable = False;
+}
+
+/// A marker for locks that allow reading and writing.
+pub struct WriteLock;
+impl LockInfo for WriteLock {
+ type Writable = True;
+}
+
+/// A generic mutual exclusion primitive.
+///
+/// [`Guard`] is written such that any mutual exclusion primitive that can implement this trait can
+/// also benefit from having an automatic way to unlock itself.
+///
+/// # Safety
+///
+/// - Implementers of this trait with the [`WriteLock`] marker must ensure that only one thread/CPU
+/// may access the protected data once the lock is held, that is, between calls to `lock_noguard`
+/// and `unlock`.
+/// - Implementers of all other markers must ensure that a mutable reference to the protected data
+/// is not active in any thread/CPU because at least one shared refence is active between calls
+/// to `lock_noguard` and `unlock`.
+pub unsafe trait Lock<I: LockInfo = WriteLock> {
+ /// The type of the data protected by the lock.
+ type Inner: ?Sized;
+
+ /// The type of context, if any, that needs to be stored in the guard.
+ type GuardContext;
+
+ /// Acquires the lock, making the caller its owner.
+ #[must_use]
+ fn lock_noguard(&self) -> Self::GuardContext;
+
+ /// Reacquires the lock, making the caller its owner.
+ ///
+ /// The guard context before the last unlock is passed in.
+ ///
+ /// Locks that don't require this state on relock can simply use the default implementation
+ /// that calls [`Lock::lock_noguard`].
+ fn relock(&self, ctx: &mut Self::GuardContext) {
+ *ctx = self.lock_noguard();
+ }
+
+ /// Releases the lock, giving up ownership of the lock.
+ ///
+ /// # Safety
+ ///
+ /// It must only be called by the current owner of the lock.
+ unsafe fn unlock(&self, context: &mut Self::GuardContext);
+
+ /// Returns the data protected by the lock.
+ fn locked_data(&self) -> &core::cell::UnsafeCell<Self::Inner>;
+}
+
+/// A creator of instances of a mutual exclusion (lock) primitive.
+pub trait LockFactory {
+ /// The parametrised type of the mutual exclusion primitive that can be created by this factory.
+ type LockedType<T>;
+
+ /// Constructs a new instance of the mutual exclusion primitive.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`LockIniter::init_lock`] before using the lock.
+ unsafe fn new_lock<T>(data: T) -> Self::LockedType<T>;
+}
+
+/// A lock that can be initialised with a single lock class key.
+pub trait LockIniter {
+ /// Initialises the lock instance so that it can be safely used.
+ ///
+ /// # Safety
+ ///
+ /// `key` must point to a valid memory location that will remain valid until the lock is
+ /// dropped.
+ unsafe fn init_lock(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ );
+}
+
+impl<L: LockIniter> NeedsLockClass for L {
+ unsafe fn init(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ _: *mut bindings::lock_class_key,
+ ) {
+ // SAFETY: The safety requirements of this function satisfy those of `init_lock`.
+ unsafe { self.init_lock(name, key) };
+ }
+}
diff --git a/rust/kernel/sync/locked_by.rs b/rust/kernel/sync/locked_by.rs
new file mode 100644
index 000000000000..334935fb1e37
--- /dev/null
+++ b/rust/kernel/sync/locked_by.rs
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A wrapper for data protected by a lock that does not wrap it.
+
+use super::{Guard, Lock};
+use core::{cell::UnsafeCell, ops::Deref, ptr};
+
+/// Allows access to some data to be serialised by a lock that does not wrap it.
+///
+/// In most cases, data protected by a lock is wrapped by the appropriate lock type, e.g.,
+/// [`super::Mutex`] or [`super::SpinLock`]. [`LockedBy`] is meant for cases when this is not
+/// possible. For example, if a container has a lock and some data in the contained elements needs
+/// to be protected by the same lock.
+///
+/// [`LockedBy`] wraps the data in lieu of another locking primitive, and only allows access to it
+/// when the caller shows evidence that 'external' lock is locked.
+///
+/// # Example
+///
+/// The following is an example for illustrative purposes: `InnerDirectory::bytes_used` is an
+/// aggregate of all `InnerFile::bytes_used` and must be kept consistent; so we wrap `InnerFile` in
+/// a `LockedBy` so that it shares a lock with `InnerDirectory`. This allows us to enforce at
+/// compile-time that access to `InnerFile` is only granted when an `InnerDirectory` is also
+/// locked; we enforce at run time that the right `InnerDirectory` is locked.
+///
+/// ```
+/// use kernel::sync::{LockedBy, Mutex};
+///
+/// struct InnerFile {
+/// bytes_used: u64,
+/// }
+///
+/// struct File {
+/// name: String,
+/// inner: LockedBy<InnerFile, Mutex<InnerDirectory>>,
+/// }
+///
+/// struct InnerDirectory {
+/// /// The sum of the bytes used by all files.
+/// bytes_used: u64,
+/// files: Vec<File>,
+/// }
+///
+/// struct Directory {
+/// name: String,
+/// inner: Mutex<InnerDirectory>,
+/// }
+/// ```
+pub struct LockedBy<T: ?Sized, L: Lock + ?Sized> {
+ owner: *const L::Inner,
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `LockedBy` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send, L: Lock + ?Sized> Send for LockedBy<T, L> {}
+
+// SAFETY: `LockedBy` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send, L: Lock + ?Sized> Sync for LockedBy<T, L> {}
+
+impl<T, L: Lock + ?Sized> LockedBy<T, L> {
+ /// Constructs a new instance of [`LockedBy`].
+ ///
+ /// It stores a raw pointer to the owner that is never dereferenced. It is only used to ensure
+ /// that the right owner is being used to access the protected data. If the owner is freed, the
+ /// data becomes inaccessible; if another instance of the owner is allocated *on the same
+ /// memory location*, the data becomes accessible again: none of this affects memory safety
+ /// because in any case at most one thread (or CPU) can access the protected data at a time.
+ pub fn new(owner: &L, data: T) -> Self {
+ Self {
+ owner: owner.locked_data().get(),
+ data: UnsafeCell::new(data),
+ }
+ }
+}
+
+impl<T: ?Sized, L: Lock + ?Sized> LockedBy<T, L> {
+ /// Returns a reference to the protected data when the caller provides evidence (via a
+ /// [`Guard`]) that the owner is locked.
+ pub fn access<'a>(&'a self, guard: &'a Guard<'_, L>) -> &'a T {
+ if !ptr::eq(guard.deref(), self.owner) {
+ panic!("guard does not match owner");
+ }
+
+ // SAFETY: `guard` is evidence that the owner is locked.
+ unsafe { &mut *self.data.get() }
+ }
+
+ /// Returns a mutable reference to the protected data when the caller provides evidence (via a
+ /// mutable [`Guard`]) that the owner is locked mutably.
+ pub fn access_mut<'a>(&'a self, guard: &'a mut Guard<'_, L>) -> &'a mut T {
+ if !ptr::eq(guard.deref().deref(), self.owner) {
+ panic!("guard does not match owner");
+ }
+
+ // SAFETY: `guard` is evidence that the owner is locked.
+ unsafe { &mut *self.data.get() }
+ }
+
+ /// Returns a mutable reference to the protected data when the caller provides evidence (via a
+ /// mutable owner) that the owner is locked mutably. Showing a mutable reference to the owner
+ /// is sufficient because we know no other references can exist to it.
+ pub fn access_from_mut<'a>(&'a self, owner: &'a mut L::Inner) -> &'a mut T {
+ if !ptr::eq(owner, self.owner) {
+ panic!("mismatched owners");
+ }
+
+ // SAFETY: `owner` is evidence that there is only one reference to the owner.
+ unsafe { &mut *self.data.get() }
+ }
+}
diff --git a/rust/kernel/sync/mutex.rs b/rust/kernel/sync/mutex.rs
new file mode 100644
index 000000000000..fac846b00b08
--- /dev/null
+++ b/rust/kernel/sync/mutex.rs
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel mutex.
+//!
+//! This module allows Rust code to use the kernel's [`struct mutex`].
+
+use super::{Guard, Lock, LockFactory, LockIniter, WriteLock};
+use crate::{bindings, str::CStr, Opaque};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`Mutex`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! mutex_init {
+ ($mutex:expr, $name:literal) => {
+ $crate::init_with_lockdep!($mutex, $name)
+ };
+}
+
+/// Exposes the kernel's [`struct mutex`]. When multiple threads attempt to lock the same mutex,
+/// only one at a time is allowed to progress, the others will block (sleep) until the mutex is
+/// unlocked, at which point another thread will be allowed to wake up and make progress.
+///
+/// A [`Mutex`] must first be initialised with a call to [`Mutex::init_lock`] before it can be
+/// used. The [`mutex_init`] macro is provided to automatically assign a new lock class to a mutex
+/// instance.
+///
+/// Since it may block, [`Mutex`] needs to be used with care in atomic contexts.
+///
+/// [`struct mutex`]: ../../../include/linux/mutex.h
+pub struct Mutex<T: ?Sized> {
+ /// The kernel `struct mutex` object.
+ mutex: Opaque<bindings::mutex>,
+
+ /// A mutex needs to be pinned because it contains a [`struct list_head`] that is
+ /// self-referential, so it cannot be safely moved once it is initialised.
+ _pin: PhantomPinned,
+
+ /// The data protected by the mutex.
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `Mutex` can be transferred across thread boundaries iff the data it protects can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
+
+// SAFETY: `Mutex` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
+
+impl<T> Mutex<T> {
+ /// Constructs a new mutex.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`Mutex::init_lock`] before using the mutex.
+ pub const unsafe fn new(t: T) -> Self {
+ Self {
+ mutex: Opaque::uninit(),
+ data: UnsafeCell::new(t),
+ _pin: PhantomPinned,
+ }
+ }
+}
+
+impl<T: ?Sized> Mutex<T> {
+ /// Locks the mutex and gives the caller access to the data protected by it. Only one thread at
+ /// a time is allowed to access the protected data.
+ pub fn lock(&self) -> Guard<'_, Self> {
+ let ctx = self.lock_noguard();
+ // SAFETY: The mutex was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+}
+
+impl<T> LockFactory for Mutex<T> {
+ type LockedType<U> = Mutex<U>;
+
+ unsafe fn new_lock<U>(data: U) -> Mutex<U> {
+ // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+ unsafe { Mutex::new(data) }
+ }
+}
+
+impl<T> LockIniter for Mutex<T> {
+ unsafe fn init_lock(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ ) {
+ unsafe { bindings::__mutex_init(self.mutex.get(), name.as_char_ptr(), key) };
+ }
+}
+
+pub struct EmptyGuardContext;
+
+// SAFETY: The underlying kernel `struct mutex` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for Mutex<T> {
+ type Inner = T;
+ type GuardContext = EmptyGuardContext;
+
+ fn lock_noguard(&self) -> EmptyGuardContext {
+ // SAFETY: `mutex` points to valid memory.
+ unsafe { bindings::mutex_lock(self.mutex.get()) };
+ EmptyGuardContext
+ }
+
+ unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+ // SAFETY: The safety requirements of the function ensure that the mutex is owned by the
+ // caller.
+ unsafe { bindings::mutex_unlock(self.mutex.get()) };
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+/// A revocable mutex.
+///
+/// That is, a mutex to which access can be revoked at runtime. It is a specialisation of the more
+/// generic [`super::revocable::Revocable`].
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::RevocableMutex;
+/// # use kernel::revocable_init;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn read_sum(v: &RevocableMutex<Example>) -> Option<u32> {
+/// let guard = v.try_write()?;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// // SAFETY: We call `revocable_init` immediately below.
+/// let mut v = unsafe { RevocableMutex::new(Example { a: 10, b: 20 }) };
+/// // SAFETY: We never move out of `v`.
+/// let pinned = unsafe { Pin::new_unchecked(&mut v) };
+/// revocable_init!(pinned, "example::v");
+/// assert_eq!(read_sum(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(read_sum(&v), None);
+/// ```
+pub type RevocableMutex<T> = super::revocable::Revocable<Mutex<()>, T>;
+
+/// A guard for a revocable mutex.
+pub type RevocableMutexGuard<'a, T, I = WriteLock> =
+ super::revocable::RevocableGuard<'a, Mutex<()>, T, I>;
diff --git a/rust/kernel/sync/nowait.rs b/rust/kernel/sync/nowait.rs
new file mode 100644
index 000000000000..c9ee2f9a3607
--- /dev/null
+++ b/rust/kernel/sync/nowait.rs
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A lock that never waits.
+
+use core::cell::UnsafeCell;
+use core::sync::atomic::{AtomicU8, Ordering};
+
+const LOCKED: u8 = 1;
+const CONTENDED: u8 = 2;
+
+/// A lock that only offers a [`try_lock`](NoWaitLock::try_lock) method.
+///
+/// That is, on contention it doesn't offer a way for the caller to block waiting for the current
+/// owner to release the lock. This is useful for best-effort kind of scenarios where waiting is
+/// never needed: in such cases, users don't need a full-featured mutex or spinlock.
+///
+/// When the lock is released via call to [`NoWaitLockGuard::unlock`], it indicates to the caller
+/// whether there was contention (i.e., if another thread tried and failed to acquire this lock).
+/// If the return value is `false`, there was definitely no contention but if it is `true`, it's
+/// possible that the contention was when attempting to acquire the lock.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::sync::NoWaitLock;
+///
+/// #[derive(PartialEq)]
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// let x = NoWaitLock::new(Example{ a: 10, b: 20 });
+///
+/// // Modifying the protected value.
+/// {
+/// let mut guard = x.try_lock().unwrap();
+/// assert_eq!(guard.a, 10);
+/// assert_eq!(guard.b, 20);
+/// guard.a += 20;
+/// guard.b += 20;
+/// assert_eq!(guard.a, 30);
+/// assert_eq!(guard.b, 40);
+/// }
+///
+/// // Reading the protected value.
+/// {
+/// let guard = x.try_lock().unwrap();
+/// assert_eq!(guard.a, 30);
+/// assert_eq!(guard.b, 40);
+/// }
+///
+/// // Second acquire fails, but succeeds after the guard is dropped.
+/// {
+/// let guard = x.try_lock().unwrap();
+/// assert!(x.try_lock().is_none());
+///
+/// drop(guard);
+/// assert!(x.try_lock().is_some());
+/// }
+/// ```
+///
+/// The following examples use the [`NoWaitLockGuard::unlock`] to release the lock and check for
+/// contention.
+///
+/// ```
+/// use kernel::sync::NoWaitLock;
+///
+/// #[derive(PartialEq)]
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// let x = NoWaitLock::new(Example{ a: 10, b: 20 });
+///
+/// // No contention when lock is released.
+/// let guard = x.try_lock().unwrap();
+/// assert_eq!(guard.unlock(), false);
+///
+/// // Contention detected.
+/// let guard = x.try_lock().unwrap();
+/// assert!(x.try_lock().is_none());
+/// assert_eq!(guard.unlock(), true);
+///
+/// // No contention again.
+/// let guard = x.try_lock().unwrap();
+/// assert_eq!(guard.a, 10);
+/// assert_eq!(guard.b, 20);
+/// assert_eq!(guard.unlock(), false);
+/// ```
+pub struct NoWaitLock<T: ?Sized> {
+ state: AtomicU8,
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `NoWaitLock` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send> Send for NoWaitLock<T> {}
+
+// SAFETY: `NoWaitLock` only allows a single thread at a time to access the interior mutability it
+// provides, so it is `Sync` as long as the data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for NoWaitLock<T> {}
+
+impl<T> NoWaitLock<T> {
+ /// Creates a new instance of the no-wait lock.
+ pub fn new(data: T) -> Self {
+ Self {
+ state: AtomicU8::new(0),
+ data: UnsafeCell::new(data),
+ }
+ }
+}
+
+impl<T: ?Sized> NoWaitLock<T> {
+ /// Tries to acquire the lock.
+ ///
+ /// If no other thread/CPU currently owns the lock, it returns a guard that can be used to
+ /// access the protected data. Otherwise (i.e., the lock is already owned), it returns `None`.
+ pub fn try_lock(&self) -> Option<NoWaitLockGuard<'_, T>> {
+ // Fast path -- just set the LOCKED bit.
+ //
+ // Acquire ordering matches the release in `NoWaitLockGuard::drop` or
+ // `NoWaitLockGuard::unlock`.
+ if self.state.fetch_or(LOCKED, Ordering::Acquire) & LOCKED == 0 {
+ // INVARIANTS: The thread that manages to set the `LOCKED` bit becomes the owner.
+ return Some(NoWaitLockGuard { lock: self });
+ }
+
+ // Set the `CONTENDED` bit.
+ //
+ // If the `LOCKED` bit has since been reset, the lock was released and the caller becomes
+ // the owner of the lock. It will see the `CONTENDED` bit when it releases the lock even if
+ // there was no additional contention but this is allowed by the interface.
+ if self.state.fetch_or(CONTENDED | LOCKED, Ordering::Relaxed) & LOCKED == 0 {
+ // INVARIANTS: The thread that manages to set the `LOCKED` bit becomes the owner.
+ Some(NoWaitLockGuard { lock: self })
+ } else {
+ None
+ }
+ }
+}
+
+/// A guard for the holder of the no-wait lock.
+///
+/// # Invariants
+///
+/// Only the current owner can have an instance of [`NoWaitLockGuard`].
+pub struct NoWaitLockGuard<'a, T: ?Sized> {
+ lock: &'a NoWaitLock<T>,
+}
+
+impl<T: ?Sized> NoWaitLockGuard<'_, T> {
+ /// Unlocks the no-wait lock.
+ ///
+ /// The return value indicates whether there was contention while the lock was held, that is,
+ /// whether another thread tried (and failed) to acquire the lock.
+ pub fn unlock(self) -> bool {
+ // Matches the acquire in `NoWaitLock::try_lock`.
+ let contention = self.lock.state.swap(0, Ordering::Release) & CONTENDED != 0;
+ core::mem::forget(self);
+ contention
+ }
+}
+
+impl<T: ?Sized> core::ops::Deref for NoWaitLockGuard<'_, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: The type invariant guarantees that only the owner has an instance of the guard,
+ // so the owner is the only one that can call this function.
+ unsafe { &*self.lock.data.get() }
+ }
+}
+
+impl<T: ?Sized> core::ops::DerefMut for NoWaitLockGuard<'_, T> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ // SAFETY: The type invariant guarantees that only the owner has an instance of the guard,
+ // so the owner is the only one that can call this function.
+ unsafe { &mut *self.lock.data.get() }
+ }
+}
+
+impl<T: ?Sized> Drop for NoWaitLockGuard<'_, T> {
+ fn drop(&mut self) {
+ // Matches the acquire in `NoWaitLock::try_lock`.
+ self.lock.state.store(0, Ordering::Release);
+ }
+}
diff --git a/rust/kernel/sync/revocable.rs b/rust/kernel/sync/revocable.rs
new file mode 100644
index 000000000000..3e5a76ee0950
--- /dev/null
+++ b/rust/kernel/sync/revocable.rs
@@ -0,0 +1,250 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Synchronisation primitives where acccess to their contents can be revoked at runtime.
+
+use crate::{
+ bindings,
+ str::CStr,
+ sync::{Guard, Lock, LockFactory, LockInfo, NeedsLockClass, ReadLock, WriteLock},
+ True,
+};
+use core::{
+ mem::MaybeUninit,
+ ops::{Deref, DerefMut},
+ pin::Pin,
+};
+
+/// The state within the revocable synchronisation primitive.
+///
+/// We don't use simply `Option<T>` because we need to drop in-place because the contents are
+/// implicitly pinned.
+///
+/// # Invariants
+///
+/// The `is_available` field determines if `data` is initialised.
+pub struct Inner<T> {
+ is_available: bool,
+ data: MaybeUninit<T>,
+}
+
+impl<T> Inner<T> {
+ fn new(data: T) -> Self {
+ // INVARIANT: `data` is initialised and `is_available` is `true`, so the state matches.
+ Self {
+ is_available: true,
+ data: MaybeUninit::new(data),
+ }
+ }
+
+ fn drop_in_place(&mut self) {
+ if !self.is_available {
+ // Already dropped.
+ return;
+ }
+
+ // INVARIANT: `data` is being dropped and `is_available` is set to `false`, so the state
+ // matches.
+ self.is_available = false;
+
+ // SAFETY: By the type invariants, `data` is valid because `is_available` was true.
+ unsafe { self.data.assume_init_drop() };
+ }
+}
+
+impl<T> Drop for Inner<T> {
+ fn drop(&mut self) {
+ self.drop_in_place();
+ }
+}
+
+/// Revocable synchronisation primitive.
+///
+/// That is, it wraps synchronisation primitives so that access to their contents can be revoked at
+/// runtime, rendering them inacessible.
+///
+/// Once access is revoked and all concurrent users complete (i.e., all existing instances of
+/// [`RevocableGuard`] are dropped), the wrapped object is also dropped.
+///
+/// For better ergonomics, we advise the use of specialisations of this struct, for example,
+/// [`super::RevocableMutex`] and [`super::RevocableRwSemaphore`]. Callers that do not need to
+/// sleep while holding on to a guard should use [`crate::revocable::Revocable`] instead, which is
+/// more efficient as it uses RCU to keep objects alive.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::{Mutex, Revocable};
+/// # use kernel::revocable_init;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn add_two(v: &Revocable<Mutex<()>, Example>) -> Option<u32> {
+/// let mut guard = v.try_write()?;
+/// guard.a += 2;
+/// guard.b += 2;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// // SAFETY: We call `revocable_init` immediately below.
+/// let mut v = unsafe { Revocable::<Mutex<()>, Example>::new(Example { a: 10, b: 20 }) };
+/// // SAFETY: We never move out of `v`.
+/// let pinned = unsafe { Pin::new_unchecked(&mut v) };
+/// revocable_init!(pinned, "example::v");
+/// assert_eq!(add_two(&v), Some(34));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+pub struct Revocable<F: LockFactory, T> {
+ inner: F::LockedType<Inner<T>>,
+}
+
+/// Safely initialises a [`Revocable`] instance with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! revocable_init {
+ ($mutex:expr, $name:literal) => {
+ $crate::init_with_lockdep!($mutex, $name)
+ };
+}
+
+impl<F: LockFactory, T> Revocable<F, T> {
+ /// Creates a new revocable instance of the given lock.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`Revocable::init`] before using the revocable synch primitive.
+ pub unsafe fn new(data: T) -> Self {
+ Self {
+ // SAFETY: The safety requirements of this function require that `Revocable::init`
+ // be called before the returned object can be used. Lock initialisation is called
+ // from `Revocable::init`.
+ inner: unsafe { F::new_lock(Inner::new(data)) },
+ }
+ }
+}
+
+impl<F: LockFactory, T> NeedsLockClass for Revocable<F, T>
+where
+ F::LockedType<Inner<T>>: NeedsLockClass,
+{
+ unsafe fn init(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key1: *mut bindings::lock_class_key,
+ key2: *mut bindings::lock_class_key,
+ ) {
+ // SAFETY: `inner` is pinned when `self` is.
+ let inner = unsafe { self.map_unchecked_mut(|r| &mut r.inner) };
+
+ // SAFETY: The safety requirements of this function satisfy the ones for `inner.init`
+ // (they're the same).
+ unsafe { inner.init(name, key1, key2) };
+ }
+}
+
+impl<F: LockFactory, T> Revocable<F, T>
+where
+ F::LockedType<Inner<T>>: Lock<Inner = Inner<T>>,
+{
+ /// Revokes access to and drops the wrapped object.
+ ///
+ /// Revocation and dropping happen after ongoing accessors complete.
+ pub fn revoke(&self) {
+ self.lock().drop_in_place();
+ }
+
+ /// Tries to lock the \[revocable\] wrapped object in write (exclusive) mode.
+ ///
+ /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+ ///
+ /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+ /// remain accessible while the guard is alive. Callers are allowed to sleep while holding on
+ /// to the returned guard.
+ pub fn try_write(&self) -> Option<RevocableGuard<'_, F, T, WriteLock>> {
+ let inner = self.lock();
+ if !inner.is_available {
+ return None;
+ }
+ Some(RevocableGuard::new(inner))
+ }
+
+ fn lock(&self) -> Guard<'_, F::LockedType<Inner<T>>> {
+ let ctx = self.inner.lock_noguard();
+ // SAFETY: The lock was acquired in the call above.
+ unsafe { Guard::new(&self.inner, ctx) }
+ }
+}
+
+impl<F: LockFactory, T> Revocable<F, T>
+where
+ F::LockedType<Inner<T>>: Lock<ReadLock, Inner = Inner<T>>,
+{
+ /// Tries to lock the \[revocable\] wrapped object in read (shared) mode.
+ ///
+ /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+ ///
+ /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+ /// remain accessible while the guard is alive. Callers are allowed to sleep while holding on
+ /// to the returned guard.
+ pub fn try_read(&self) -> Option<RevocableGuard<'_, F, T, ReadLock>> {
+ let ctx = self.inner.lock_noguard();
+ // SAFETY: The lock was acquired in the call above.
+ let inner = unsafe { Guard::new(&self.inner, ctx) };
+ if !inner.is_available {
+ return None;
+ }
+ Some(RevocableGuard::new(inner))
+ }
+}
+
+/// A guard that allows access to a revocable object and keeps it alive.
+pub struct RevocableGuard<'a, F: LockFactory, T, I: LockInfo>
+where
+ F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+ guard: Guard<'a, F::LockedType<Inner<T>>, I>,
+}
+
+impl<'a, F: LockFactory, T, I: LockInfo> RevocableGuard<'a, F, T, I>
+where
+ F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+ fn new(guard: Guard<'a, F::LockedType<Inner<T>>, I>) -> Self {
+ Self { guard }
+ }
+}
+
+impl<F: LockFactory, T, I: LockInfo<Writable = True>> RevocableGuard<'_, F, T, I>
+where
+ F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+ /// Returns a pinned mutable reference to the wrapped object.
+ pub fn as_pinned_mut(&mut self) -> Pin<&mut T> {
+ // SAFETY: Revocable mutexes must be pinned, so we choose to always project the data as
+ // pinned as well (i.e., we guarantee we never move it).
+ unsafe { Pin::new_unchecked(&mut *self) }
+ }
+}
+
+impl<F: LockFactory, T, I: LockInfo> Deref for RevocableGuard<'_, F, T, I>
+where
+ F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ unsafe { &*self.guard.data.as_ptr() }
+ }
+}
+
+impl<F: LockFactory, T, I: LockInfo<Writable = True>> DerefMut for RevocableGuard<'_, F, T, I>
+where
+ F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ unsafe { &mut *self.guard.data.as_mut_ptr() }
+ }
+}
diff --git a/rust/kernel/sync/rwsem.rs b/rust/kernel/sync/rwsem.rs
new file mode 100644
index 000000000000..eb220e4972cf
--- /dev/null
+++ b/rust/kernel/sync/rwsem.rs
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel read/write mutex.
+//!
+//! This module allows Rust code to use the kernel's [`struct rw_semaphore`].
+//!
+//! C header: [`include/linux/rwsem.h`](../../../../include/linux/rwsem.h)
+
+use super::{mutex::EmptyGuardContext, Guard, Lock, LockFactory, LockIniter, ReadLock, WriteLock};
+use crate::{bindings, str::CStr, Opaque};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`RwSemaphore`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! rwsemaphore_init {
+ ($rwsem:expr, $name:literal) => {
+ $crate::init_with_lockdep!($rwsem, $name)
+ };
+}
+
+/// Exposes the kernel's [`struct rw_semaphore`].
+///
+/// It's a read/write mutex. That is, it allows multiple readers to acquire it concurrently, but
+/// only one writer at a time. On contention, waiters sleep.
+///
+/// A [`RwSemaphore`] must first be initialised with a call to [`RwSemaphore::init_lock`] before it
+/// can be used. The [`rwsemaphore_init`] macro is provided to automatically assign a new lock
+/// class to an [`RwSemaphore`] instance.
+///
+/// Since it may block, [`RwSemaphore`] needs to be used with care in atomic contexts.
+///
+/// [`struct rw_semaphore`]: ../../../include/linux/rwsem.h
+pub struct RwSemaphore<T: ?Sized> {
+ /// The kernel `struct rw_semaphore` object.
+ rwsem: Opaque<bindings::rw_semaphore>,
+
+ /// An rwsem needs to be pinned because it contains a [`struct list_head`] that is
+ /// self-referential, so it cannot be safely moved once it is initialised.
+ _pin: PhantomPinned,
+
+ /// The data protected by the rwsem.
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `RwSemaphore` can be transferred across thread boundaries iff the data it protects can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: ?Sized + Send> Send for RwSemaphore<T> {}
+
+// SAFETY: `RwSemaphore` requires that the protected type be `Sync` for it to be `Sync` as well
+// because the read mode allows multiple threads to access the protected data concurrently. It
+// requires `Send` because the write lock allows a `&mut T` to be accessible from an arbitrary
+// thread.
+unsafe impl<T: ?Sized + Send + Sync> Sync for RwSemaphore<T> {}
+
+impl<T> RwSemaphore<T> {
+ /// Constructs a new rw semaphore.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`RwSemaphore::init_lock`] before using the rw semaphore.
+ pub unsafe fn new(t: T) -> Self {
+ Self {
+ rwsem: Opaque::uninit(),
+ data: UnsafeCell::new(t),
+ _pin: PhantomPinned,
+ }
+ }
+}
+
+impl<T: ?Sized> RwSemaphore<T> {
+ /// Locks the rw semaphore in write (exclusive) mode and gives the caller access to the data
+ /// protected by it. Only one thread at a time is allowed to access the protected data.
+ pub fn write(&self) -> Guard<'_, Self> {
+ let ctx = <Self as Lock>::lock_noguard(self);
+ // SAFETY: The rw semaphore was just acquired in write mode.
+ unsafe { Guard::new(self, ctx) }
+ }
+
+ /// Locks the rw semaphore in read (shared) mode and gives the caller access to the data
+ /// protected by it. Only one thread at a time is allowed to access the protected data.
+ pub fn read(&self) -> Guard<'_, Self, ReadLock> {
+ let ctx = <Self as Lock<ReadLock>>::lock_noguard(self);
+ // SAFETY: The rw semaphore was just acquired in read mode.
+ unsafe { Guard::new(self, ctx) }
+ }
+}
+
+impl<T> LockFactory for RwSemaphore<T> {
+ type LockedType<U> = RwSemaphore<U>;
+
+ unsafe fn new_lock<U>(data: U) -> RwSemaphore<U> {
+ // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+ unsafe { RwSemaphore::new(data) }
+ }
+}
+
+impl<T> LockIniter for RwSemaphore<T> {
+ unsafe fn init_lock(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ ) {
+ unsafe { bindings::__init_rwsem(self.rwsem.get(), name.as_char_ptr(), key) };
+ }
+}
+
+// SAFETY: The underlying kernel `struct rw_semaphore` object ensures mutual exclusion because it's
+// acquired in write mode.
+unsafe impl<T: ?Sized> Lock for RwSemaphore<T> {
+ type Inner = T;
+ type GuardContext = EmptyGuardContext;
+
+ fn lock_noguard(&self) -> EmptyGuardContext {
+ // SAFETY: `rwsem` points to valid memory.
+ unsafe { bindings::down_write(self.rwsem.get()) };
+ EmptyGuardContext
+ }
+
+ unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+ // SAFETY: The safety requirements of the function ensure that the rw semaphore is owned by
+ // the caller.
+ unsafe { bindings::up_write(self.rwsem.get()) };
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+// SAFETY: The underlying kernel `struct rw_semaphore` object ensures that only shared references
+// are accessible from other threads because it's acquired in read mode.
+unsafe impl<T: ?Sized> Lock<ReadLock> for RwSemaphore<T> {
+ type Inner = T;
+ type GuardContext = EmptyGuardContext;
+
+ fn lock_noguard(&self) -> EmptyGuardContext {
+ // SAFETY: `rwsem` points to valid memory.
+ unsafe { bindings::down_read(self.rwsem.get()) };
+ EmptyGuardContext
+ }
+
+ unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+ // SAFETY: The safety requirements of the function ensure that the rw semaphore is owned by
+ // the caller.
+ unsafe { bindings::up_read(self.rwsem.get()) };
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+/// A revocable rw semaphore.
+///
+/// That is, a read/write semaphore to which access can be revoked at runtime. It is a
+/// specialisation of the more generic [`super::revocable::Revocable`].
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::RevocableRwSemaphore;
+/// # use kernel::revocable_init;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// fn read_sum(v: &RevocableRwSemaphore<Example>) -> Option<u32> {
+/// let guard = v.try_read()?;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// fn add_two(v: &RevocableRwSemaphore<Example>) -> Option<u32> {
+/// let mut guard = v.try_write()?;
+/// guard.a += 2;
+/// guard.b += 2;
+/// Some(guard.a + guard.b)
+/// }
+///
+/// // SAFETY: We call `revocable_init` immediately below.
+/// let mut v = unsafe { RevocableRwSemaphore::new(Example { a: 10, b: 20 }) };
+/// // SAFETY: We never move out of `v`.
+/// let pinned = unsafe { Pin::new_unchecked(&mut v) };
+/// revocable_init!(pinned, "example::v");
+/// assert_eq!(read_sum(&v), Some(30));
+/// assert_eq!(add_two(&v), Some(34));
+/// v.revoke();
+/// assert_eq!(read_sum(&v), None);
+/// assert_eq!(add_two(&v), None);
+/// ```
+pub type RevocableRwSemaphore<T> = super::revocable::Revocable<RwSemaphore<()>, T>;
+
+/// A guard for a revocable rw semaphore..
+pub type RevocableRwSemaphoreGuard<'a, T, I = WriteLock> =
+ super::revocable::RevocableGuard<'a, RwSemaphore<()>, T, I>;
diff --git a/rust/kernel/sync/seqlock.rs b/rust/kernel/sync/seqlock.rs
new file mode 100644
index 000000000000..f42d649823c6
--- /dev/null
+++ b/rust/kernel/sync/seqlock.rs
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel sequential lock (seqlock).
+//!
+//! This module allows Rust code to use the sequential locks based on the kernel's `seqcount_t` and
+//! any locks implementing the [`LockFactory`] trait.
+//!
+//! See <https://www.kernel.org/doc/Documentation/locking/seqlock.rst>.
+
+use super::{Guard, Lock, LockFactory, LockIniter, NeedsLockClass, ReadLock};
+use crate::{bindings, str::CStr, Opaque};
+use core::{cell::UnsafeCell, marker::PhantomPinned, ops::Deref, pin::Pin};
+
+/// Exposes sequential locks backed by the kernel's `seqcount_t`.
+///
+/// The write-side critical section is protected by a lock implementing the [`LockFactory`] trait.
+///
+/// # Examples
+///
+///```
+/// use kernel::sync::{SeqLock, SpinLock};
+/// use core::sync::atomic::{AtomicU32, Ordering};
+///
+/// struct Example {
+/// a: AtomicU32,
+/// b: AtomicU32,
+/// }
+///
+/// fn get_sum(v: &SeqLock<SpinLock<Example>>) -> u32 {
+/// // Use `access` to access the fields of `Example`.
+/// v.access(|e| e.a.load(Ordering::Relaxed) + e.b.load(Ordering::Relaxed))
+/// }
+///
+/// fn get_sum_with_guard(v: &SeqLock<SpinLock<Example>>) -> u32 {
+/// // Use `read` and `need_retry` in a loop to access the fields of `Example`.
+/// loop {
+/// let guard = v.read();
+/// let sum = guard.a.load(Ordering::Relaxed) + guard.b.load(Ordering::Relaxed);
+/// if !guard.need_retry() {
+/// break sum;
+/// }
+/// }
+/// }
+///
+/// fn inc_each(v: &SeqLock<SpinLock<Example>>) {
+/// // Use a write-side guard to access the fields of `Example`.
+/// let guard = v.write();
+/// let a = guard.a.load(Ordering::Relaxed);
+/// guard.a.store(a + 1, Ordering::Relaxed);
+/// let b = guard.b.load(Ordering::Relaxed);
+/// guard.b.store(b + 1, Ordering::Relaxed);
+/// }
+/// ```
+pub struct SeqLock<L: Lock + ?Sized> {
+ _p: PhantomPinned,
+ count: Opaque<bindings::seqcount>,
+ write_lock: L,
+}
+
+// SAFETY: `SeqLock` can be transferred across thread boundaries iff the data it protects and the
+// underlying lock can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<L: Lock + Send> Send for SeqLock<L> where L::Inner: Send {}
+
+// SAFETY: `SeqLock` allows concurrent access to the data it protects by both readers and writers,
+// so it requires that the data it protects be `Sync`, as well as the underlying lock.
+unsafe impl<L: Lock + Sync> Sync for SeqLock<L> where L::Inner: Sync {}
+
+impl<L: Lock> SeqLock<L> {
+ /// Constructs a new instance of [`SeqLock`].
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`SeqLock::init`] before using the seqlock.
+ pub unsafe fn new(data: L::Inner) -> Self
+ where
+ L: LockFactory<LockedType<L::Inner> = L>,
+ L::Inner: Sized,
+ {
+ Self {
+ _p: PhantomPinned,
+ count: Opaque::uninit(),
+ // SAFETY: `L::init_lock` is called from `SeqLock::init`, which is required to be
+ // called by the function's safety requirements.
+ write_lock: unsafe { L::new_lock(data) },
+ }
+ }
+}
+
+impl<L: Lock + ?Sized> SeqLock<L> {
+ /// Accesses the protected data in read mode.
+ ///
+ /// Readers and writers are allowed to run concurrently, so callers must check if they need to
+ /// refetch the values before they are used (e.g., because a writer changed them concurrently,
+ /// rendering them potentially inconsistent). The check is performed via calls to
+ /// [`SeqLockReadGuard::need_retry`].
+ pub fn read(&self) -> SeqLockReadGuard<'_, L> {
+ SeqLockReadGuard {
+ lock: self,
+ // SAFETY: `count` contains valid memory.
+ start_count: unsafe { bindings::read_seqcount_begin(self.count.get()) },
+ }
+ }
+
+ /// Accesses the protected data in read mode.
+ ///
+ /// The provided closure is called repeatedly if it may have accessed inconsistent data (e.g.,
+ /// because a concurrent writer modified it). This is a wrapper around [`SeqLock::read`] and
+ /// [`SeqLockReadGuard::need_retry`] in a loop.
+ pub fn access<F: Fn(&L::Inner) -> R, R>(&self, cb: F) -> R {
+ loop {
+ let guard = self.read();
+ let ret = cb(&guard);
+ if !guard.need_retry() {
+ return ret;
+ }
+ }
+ }
+
+ /// Locks the underlying lock and returns a guard that allows access to the protected data.
+ ///
+ /// The guard is not mutable though because readers are still allowed to concurrently access
+ /// the data. The protected data structure needs to provide interior mutability itself (e.g.,
+ /// via atomic types) for the individual fields that can be mutated.
+ pub fn write(&self) -> Guard<'_, Self, ReadLock> {
+ let ctx = self.lock_noguard();
+ // SAFETY: The seqlock was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+}
+
+impl<L: LockIniter + Lock + ?Sized> NeedsLockClass for SeqLock<L> {
+ unsafe fn init(
+ mut self: Pin<&mut Self>,
+ name: &'static CStr,
+ key1: *mut bindings::lock_class_key,
+ key2: *mut bindings::lock_class_key,
+ ) {
+ // SAFETY: `write_lock` is pinned when `self` is.
+ let pinned = unsafe { self.as_mut().map_unchecked_mut(|s| &mut s.write_lock) };
+ // SAFETY: `key1` is valid by the safety requirements of this function.
+ unsafe { pinned.init_lock(name, key1) };
+ // SAFETY: `key2` is valid by the safety requirements of this function.
+ unsafe { bindings::__seqcount_init(self.count.get(), name.as_char_ptr(), key2) };
+ }
+}
+
+// SAFETY: The underlying lock ensures mutual exclusion.
+unsafe impl<L: Lock + ?Sized> Lock<ReadLock> for SeqLock<L> {
+ type Inner = L::Inner;
+ type GuardContext = L::GuardContext;
+
+ fn lock_noguard(&self) -> L::GuardContext {
+ let ctx = self.write_lock.lock_noguard();
+ // SAFETY: `count` contains valid memory.
+ unsafe { bindings::write_seqcount_begin(self.count.get()) };
+ ctx
+ }
+
+ fn relock(&self, ctx: &mut L::GuardContext) {
+ self.write_lock.relock(ctx);
+ // SAFETY: `count` contains valid memory.
+ unsafe { bindings::write_seqcount_begin(self.count.get()) };
+ }
+
+ unsafe fn unlock(&self, ctx: &mut L::GuardContext) {
+ // SAFETY: The safety requirements of the function ensure that lock is owned by the caller.
+ unsafe { bindings::write_seqcount_end(self.count.get()) };
+ // SAFETY: The safety requirements of the function ensure that lock is owned by the caller.
+ unsafe { self.write_lock.unlock(ctx) };
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<L::Inner> {
+ self.write_lock.locked_data()
+ }
+}
+
+/// Allows read-side access to data protected by a sequential lock.
+pub struct SeqLockReadGuard<'a, L: Lock + ?Sized> {
+ lock: &'a SeqLock<L>,
+ start_count: u32,
+}
+
+impl<L: Lock + ?Sized> SeqLockReadGuard<'_, L> {
+ /// Determine if the callers needs to retry reading values.
+ ///
+ /// It returns `true` when a concurrent writer ran between the guard being created and
+ /// [`Self::need_retry`] being called.
+ pub fn need_retry(&self) -> bool {
+ // SAFETY: `count` is valid because the guard guarantees that the lock remains alive.
+ unsafe { bindings::read_seqcount_retry(self.lock.count.get(), self.start_count) != 0 }
+ }
+}
+
+impl<L: Lock + ?Sized> Deref for SeqLockReadGuard<'_, L> {
+ type Target = L::Inner;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: We only ever allow shared access to the protected data.
+ unsafe { &*self.lock.locked_data().get() }
+ }
+}
diff --git a/rust/kernel/sync/smutex.rs b/rust/kernel/sync/smutex.rs
new file mode 100644
index 000000000000..4f6797361ab3
--- /dev/null
+++ b/rust/kernel/sync/smutex.rs
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A simple mutex implementation.
+//!
+//! Differently from [`super::Mutex`], this implementation does not require pinning, so the
+//! ergonomics are much improved, though the implementation is not as feature-rich as the C-based
+//! one. The main advantage is that it doesn't impose unsafe blocks on callers.
+//!
+//! The mutex is made up of 2 words in addition to the data it protects. The first one is accessed
+//! concurrently by threads trying to acquire and release the mutex, it contains a "stack" of
+//! waiters and a "locked" bit; the second one is only accessible by the thread holding the mutex,
+//! it contains a queue of waiters. Waiters are moved from the stack to the queue when the mutex is
+//! next unlocked while the stack is non-empty and the queue is empty. A single waiter is popped
+//! from the wait queue when the owner of the mutex unlocks it.
+//!
+//! The initial state of the mutex is `<locked=0, stack=[], queue=[]>`, meaning that it isn't
+//! locked and both the waiter stack and queue are empty.
+//!
+//! A lock operation transitions the mutex to state `<locked=1, stack=[], queue=[]>`.
+//!
+//! An unlock operation transitions the mutex back to the initial state, however, an attempt to
+//! lock the mutex while it's already locked results in a waiter being created (on the stack) and
+//! pushed onto the stack, so the state is `<locked=1, stack=[W1], queue=[]>`.
+//!
+//! Another thread trying to lock the mutex results in another waiter being pushed onto the stack,
+//! so the state becomes `<locked=1, stack=[W2, W1], queue=[]>`.
+//!
+//! In such states (queue is empty but stack is non-empty), the unlock operation is performed in
+//! three steps:
+//! 1. The stack is popped (but the mutex remains locked), so the state is:
+//! `<locked=1, stack=[], queue=[]>`
+//! 2. The stack is turned into a queue by reversing it, so the state is:
+//! `<locked=1, stack=[], queue=[W1, W2]>
+//! 3. Finally, the lock is released, and the first waiter is awakened, so the state is:
+//! `<locked=0, stack=[], queue=[W2]>`
+//!
+//! The mutex remains accessible to any threads attempting to lock it in any of the intermediate
+//! states above. For example, while it is locked, other threads may add waiters to the stack
+//! (which is ok because we want to release the ones on the queue first); another example is that
+//! another thread may acquire the mutex before waiter W1 in the example above, this makes the
+//! mutex unfair but this is desirable because the thread is running already and may in fact
+//! release the lock before W1 manages to get scheduled -- it also mitigates the lock convoy
+//! problem when the releasing thread wants to immediately acquire the lock again: it will be
+//! allowed to do so (as long as W1 doesn't get to it first).
+//!
+//! When the waiter queue is non-empty, unlocking the mutex always results in the first waiter being
+//! popped form the queue and awakened.
+
+use super::{mutex::EmptyGuardContext, Guard, Lock, LockFactory, LockIniter};
+use crate::{bindings, str::CStr, Opaque};
+use core::sync::atomic::{AtomicUsize, Ordering};
+use core::{cell::UnsafeCell, pin::Pin};
+
+/// The value that is OR'd into the [`Mutex::waiter_stack`] when the mutex is locked.
+const LOCKED: usize = 1;
+
+/// A simple mutex.
+///
+/// This is mutual-exclusion primitive. It guarantees that only one thread at a time may access the
+/// data it protects. When multiple threads attempt to lock the same mutex, only one at a time is
+/// allowed to progress, the others will block (sleep) until the mutex is unlocked, at which point
+/// another thread will be allowed to wake up and make progress.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{Result, sync::Ref, sync::smutex::Mutex};
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// static EXAMPLE: Mutex<Example> = Mutex::new(Example{ a: 10, b: 20 });
+///
+/// fn inc_a(example: &Mutex<Example>) {
+/// let mut guard = example.lock();
+/// guard.a += 1;
+/// }
+///
+/// fn sum(example: &Mutex<Example>) -> u32 {
+/// let guard = example.lock();
+/// guard.a + guard.b
+/// }
+///
+/// fn try_new(a: u32, b: u32) -> Result<Ref<Mutex<Example>>> {
+/// Ref::try_new(Mutex::new(Example {a, b}))
+/// }
+///
+/// assert_eq!(EXAMPLE.lock().a, 10);
+/// assert_eq!(sum(&EXAMPLE), 30);
+///
+/// inc_a(&EXAMPLE);
+///
+/// assert_eq!(EXAMPLE.lock().a, 11);
+/// assert_eq!(sum(&EXAMPLE), 31);
+///
+/// # try_new(42, 43);
+/// ```
+pub struct Mutex<T: ?Sized> {
+ /// A stack of waiters.
+ ///
+ /// It is accessed atomically by threads lock/unlocking the mutex. Additionally, the
+ /// least-significant bit is used to indicate whether the mutex is locked or not.
+ waiter_stack: AtomicUsize,
+
+ /// A queue of waiters.
+ ///
+ /// This is only accessible to the holder of the mutex. When the owner of the mutex is
+ /// unlocking it, it will move waiters from the stack to the queue when the queue is empty and
+ /// the stack non-empty.
+ waiter_queue: UnsafeCell<*mut Waiter>,
+
+ /// The data protected by the mutex.
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `Mutex` can be transferred across thread boundaries iff the data it protects can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
+
+// SAFETY: `Mutex` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
+
+impl<T> Mutex<T> {
+ /// Creates a new instance of the mutex.
+ pub const fn new(data: T) -> Self {
+ Self {
+ waiter_stack: AtomicUsize::new(0),
+ waiter_queue: UnsafeCell::new(core::ptr::null_mut()),
+ data: UnsafeCell::new(data),
+ }
+ }
+}
+
+impl<T: ?Sized> Mutex<T> {
+ /// Locks the mutex and gives the caller access to the data protected by it. Only one thread at
+ /// a time is allowed to access the protected data.
+ pub fn lock(&self) -> Guard<'_, Self> {
+ let ctx = self.lock_noguard();
+ // SAFETY: The mutex was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+}
+
+impl<T> LockFactory for Mutex<T> {
+ type LockedType<U> = Mutex<U>;
+
+ unsafe fn new_lock<U>(data: U) -> Mutex<U> {
+ Mutex::new(data)
+ }
+}
+
+impl<T> LockIniter for Mutex<T> {
+ unsafe fn init_lock(
+ self: Pin<&mut Self>,
+ _name: &'static CStr,
+ _key: *mut bindings::lock_class_key,
+ ) {
+ }
+}
+
+// SAFETY: The mutex implementation ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for Mutex<T> {
+ type Inner = T;
+ type GuardContext = EmptyGuardContext;
+
+ fn lock_noguard(&self) -> EmptyGuardContext {
+ loop {
+ // Try the fast path: the caller owns the mutex if we manage to set the `LOCKED` bit.
+ //
+ // The `acquire` order matches with one of the `release` ones in `unlock`.
+ if self.waiter_stack.fetch_or(LOCKED, Ordering::Acquire) & LOCKED == 0 {
+ return EmptyGuardContext;
+ }
+
+ // Slow path: we'll likely need to wait, so initialise a local waiter struct.
+ let mut waiter = Waiter {
+ completion: Opaque::uninit(),
+ next: core::ptr::null_mut(),
+ };
+
+ // SAFETY: The completion object was just allocated on the stack and is valid for
+ // writes.
+ unsafe { bindings::init_completion(waiter.completion.get()) };
+
+ // Try to enqueue the waiter by pushing into onto the waiter stack. We want to do it
+ // only while the mutex is locked by another thread.
+ loop {
+ // We use relaxed here because we're just reading the value we'll CAS later (which
+ // has a stronger ordering on success).
+ let mut v = self.waiter_stack.load(Ordering::Relaxed);
+ if v & LOCKED == 0 {
+ // The mutex was released by another thread, so try to acquire it.
+ //
+ // The `acquire` order matches with one of the `release` ones in `unlock`.
+ v = self.waiter_stack.fetch_or(LOCKED, Ordering::Acquire);
+ if v & LOCKED == 0 {
+ return EmptyGuardContext;
+ }
+ }
+
+ waiter.next = (v & !LOCKED) as _;
+
+ // The `release` order matches with `acquire` in `unlock` when the stack is swapped
+ // out. We use release order here to ensure that the other thread can see our
+ // waiter fully initialised.
+ if self
+ .waiter_stack
+ .compare_exchange(
+ v,
+ (&mut waiter as *mut _ as usize) | LOCKED,
+ Ordering::Release,
+ Ordering::Relaxed,
+ )
+ .is_ok()
+ {
+ break;
+ }
+ }
+
+ // Wait for the owner to lock to wake this thread up.
+ //
+ // SAFETY: Completion object was previously initialised with `init_completion` and
+ // remains valid.
+ unsafe { bindings::wait_for_completion(waiter.completion.get()) };
+ }
+ }
+
+ unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+ // SAFETY: The caller owns the mutex, so it is safe to manipulate the local wait queue.
+ let mut waiter = unsafe { *self.waiter_queue.get() };
+ loop {
+ // If we have a non-empty local queue of waiters, pop the first one, release the mutex,
+ // and wake it up (the popped waiter).
+ if !waiter.is_null() {
+ // SAFETY: The caller owns the mutex, so it is safe to manipulate the local wait
+ // queue.
+ unsafe { *self.waiter_queue.get() = (*waiter).next };
+
+ // The `release` order matches with one of the `acquire` ones in `lock_noguard`.
+ self.waiter_stack.fetch_and(!LOCKED, Ordering::Release);
+
+ // Wake up the first waiter.
+ //
+ // SAFETY: The completion object was initialised before being added to the wait
+ // stack and is only removed above, when called completed. So it is safe for
+ // writes.
+ unsafe { bindings::complete_all((*waiter).completion.get()) };
+ return;
+ }
+
+ // Try the fast path when there are no local waiters.
+ //
+ // The `release` order matches with one of the `acquire` ones in `lock_noguard`.
+ if self
+ .waiter_stack
+ .compare_exchange(LOCKED, 0, Ordering::Release, Ordering::Relaxed)
+ .is_ok()
+ {
+ return;
+ }
+
+ // We don't have a local queue, so pull the whole stack off, reverse it, and use it as a
+ // local queue. Since we're manipulating this queue, we need to keep ownership of the
+ // mutex.
+ //
+ // The `acquire` order matches with the `release` one in `lock_noguard` where a waiter
+ // is pushed onto the stack. It ensures that we see the fully-initialised waiter.
+ let mut stack =
+ (self.waiter_stack.swap(LOCKED, Ordering::Acquire) & !LOCKED) as *mut Waiter;
+ while !stack.is_null() {
+ // SAFETY: The caller still owns the mutex, so it is safe to manipulate the
+ // elements of the wait queue, which will soon become that wait queue.
+ let next = unsafe { (*stack).next };
+
+ // SAFETY: Same as above.
+ unsafe { (*stack).next = waiter };
+
+ waiter = stack;
+ stack = next;
+ }
+ }
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+struct Waiter {
+ completion: Opaque<bindings::completion>,
+ next: *mut Waiter,
+}
diff --git a/rust/kernel/sync/spinlock.rs b/rust/kernel/sync/spinlock.rs
new file mode 100644
index 000000000000..fb324d63127f
--- /dev/null
+++ b/rust/kernel/sync/spinlock.rs
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel spinlock.
+//!
+//! This module allows Rust code to use the kernel's [`struct spinlock`].
+//!
+//! See <https://www.kernel.org/doc/Documentation/locking/spinlocks.txt>.
+
+use super::{mutex::EmptyGuardContext, Guard, Lock, LockFactory, LockInfo, LockIniter, WriteLock};
+use crate::{bindings, c_types, str::CStr, Opaque, True};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`SpinLock`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! spinlock_init {
+ ($spinlock:expr, $name:literal) => {
+ $crate::init_with_lockdep!($spinlock, $name)
+ };
+}
+
+/// Exposes the kernel's [`spinlock_t`]. When multiple CPUs attempt to lock the same spinlock, only
+/// one at a time is allowed to progress, the others will block (spinning) until the spinlock is
+/// unlocked, at which point another CPU will be allowed to make progress.
+///
+/// A [`SpinLock`] must first be initialised with a call to [`SpinLock::init_lock`] before it can be
+/// used. The [`spinlock_init`] macro is provided to automatically assign a new lock class to a
+/// spinlock instance.
+///
+/// There are two ways to acquire the lock:
+/// - [`SpinLock::lock`], which doesn't manage interrupt state, so it should be used in only two
+/// cases: (a) when the caller knows that interrupts are disabled, or (b) when callers never use
+/// it in atomic context (e.g., interrupt handlers), in which case it is ok for interrupts to be
+/// enabled.
+/// - [`SpinLock::lock_irqdisable`], which disables interrupts if they are enabled before
+/// acquiring the lock. When the lock is released, the interrupt state is automatically returned
+/// to its value before [`SpinLock::lock_irqdisable`] was called.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::SpinLock;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// // Function that acquires spinlock without changing interrupt state.
+/// fn lock_example(value: &SpinLock<Example>) {
+/// let mut guard = value.lock();
+/// guard.a = 10;
+/// guard.b = 20;
+/// }
+///
+/// // Function that acquires spinlock and disables interrupts while holding it.
+/// fn lock_irqdisable_example(value: &SpinLock<Example>) {
+/// let mut guard = value.lock_irqdisable();
+/// guard.a = 30;
+/// guard.b = 40;
+/// }
+///
+/// // Initialises a spinlock.
+/// // SAFETY: `spinlock_init` is called below.
+/// let mut value = unsafe { SpinLock::new(Example { a: 1, b: 2 }) };
+/// // SAFETY: We don't move `value`.
+/// kernel::spinlock_init!(unsafe { Pin::new_unchecked(&mut value) }, "value");
+///
+/// // Calls the example functions.
+/// assert_eq!(value.lock().a, 1);
+/// lock_example(&value);
+/// assert_eq!(value.lock().a, 10);
+/// lock_irqdisable_example(&value);
+/// assert_eq!(value.lock().a, 30);
+/// ```
+///
+/// [`spinlock_t`]: ../../../include/linux/spinlock.h
+pub struct SpinLock<T: ?Sized> {
+ spin_lock: Opaque<bindings::spinlock>,
+
+ /// Spinlocks are architecture-defined. So we conservatively require them to be pinned in case
+ /// some architecture uses self-references now or in the future.
+ _pin: PhantomPinned,
+
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `SpinLock` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send> Send for SpinLock<T> {}
+
+// SAFETY: `SpinLock` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for SpinLock<T> {}
+
+impl<T> SpinLock<T> {
+ /// Constructs a new spinlock.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`SpinLock::init_lock`] before using the spinlock.
+ pub const unsafe fn new(t: T) -> Self {
+ Self {
+ spin_lock: Opaque::uninit(),
+ data: UnsafeCell::new(t),
+ _pin: PhantomPinned,
+ }
+ }
+}
+
+impl<T: ?Sized> SpinLock<T> {
+ /// Locks the spinlock and gives the caller access to the data protected by it. Only one thread
+ /// at a time is allowed to access the protected data.
+ pub fn lock(&self) -> Guard<'_, Self, WriteLock> {
+ let ctx = <Self as Lock<WriteLock>>::lock_noguard(self);
+ // SAFETY: The spinlock was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+
+ /// Locks the spinlock and gives the caller access to the data protected by it. Additionally it
+ /// disables interrupts (if they are enabled).
+ ///
+ /// When the lock in unlocked, the interrupt state (enabled/disabled) is restored.
+ pub fn lock_irqdisable(&self) -> Guard<'_, Self, DisabledInterrupts> {
+ let ctx = <Self as Lock<DisabledInterrupts>>::lock_noguard(self);
+ // SAFETY: The spinlock was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+}
+
+impl<T> LockFactory for SpinLock<T> {
+ type LockedType<U> = SpinLock<U>;
+
+ unsafe fn new_lock<U>(data: U) -> SpinLock<U> {
+ // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+ unsafe { SpinLock::new(data) }
+ }
+}
+
+impl<T> LockIniter for SpinLock<T> {
+ unsafe fn init_lock(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ ) {
+ unsafe { bindings::__spin_lock_init(self.spin_lock.get(), name.as_char_ptr(), key) };
+ }
+}
+
+/// A type state indicating that interrupts were disabled.
+pub struct DisabledInterrupts;
+impl LockInfo for DisabledInterrupts {
+ type Writable = True;
+}
+
+// SAFETY: The underlying kernel `spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for SpinLock<T> {
+ type Inner = T;
+ type GuardContext = EmptyGuardContext;
+
+ fn lock_noguard(&self) -> EmptyGuardContext {
+ // SAFETY: `spin_lock` points to valid memory.
+ unsafe { bindings::spin_lock(self.spin_lock.get()) };
+ EmptyGuardContext
+ }
+
+ unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+ // SAFETY: The safety requirements of the function ensure that the spinlock is owned by
+ // the caller.
+ unsafe { bindings::spin_unlock(self.spin_lock.get()) }
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+// SAFETY: The underlying kernel `spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock<DisabledInterrupts> for SpinLock<T> {
+ type Inner = T;
+ type GuardContext = c_types::c_ulong;
+
+ fn lock_noguard(&self) -> c_types::c_ulong {
+ // SAFETY: `spin_lock` points to valid memory.
+ unsafe { bindings::spin_lock_irqsave(self.spin_lock.get()) }
+ }
+
+ unsafe fn unlock(&self, ctx: &mut c_types::c_ulong) {
+ // SAFETY: The safety requirements of the function ensure that the spinlock is owned by
+ // the caller.
+ unsafe { bindings::spin_unlock_irqrestore(self.spin_lock.get(), *ctx) }
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+/// Safely initialises a [`RawSpinLock`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! rawspinlock_init {
+ ($spinlock:expr, $name:literal) => {
+ $crate::init_with_lockdep!($spinlock, $name)
+ };
+}
+
+/// Exposes the kernel's [`raw_spinlock_t`].
+///
+/// It is very similar to [`SpinLock`], except that it is guaranteed not to sleep even on RT
+/// variants of the kernel.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::RawSpinLock;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+/// a: u32,
+/// b: u32,
+/// }
+///
+/// // Function that acquires the raw spinlock without changing interrupt state.
+/// fn lock_example(value: &RawSpinLock<Example>) {
+/// let mut guard = value.lock();
+/// guard.a = 10;
+/// guard.b = 20;
+/// }
+///
+/// // Function that acquires the raw spinlock and disables interrupts while holding it.
+/// fn lock_irqdisable_example(value: &RawSpinLock<Example>) {
+/// let mut guard = value.lock_irqdisable();
+/// guard.a = 30;
+/// guard.b = 40;
+/// }
+///
+/// // Initialises a raw spinlock and calls the example functions.
+/// fn spinlock_example() {
+/// // SAFETY: `rawspinlock_init` is called below.
+/// let mut value = unsafe { RawSpinLock::new(Example { a: 1, b: 2 }) };
+/// // SAFETY: We don't move `value`.
+/// kernel::rawspinlock_init!(unsafe { Pin::new_unchecked(&mut value) }, "value");
+/// lock_example(&value);
+/// lock_irqdisable_example(&value);
+/// }
+/// ```
+///
+/// [`raw_spinlock_t`]: ../../../include/linux/spinlock.h
+pub struct RawSpinLock<T: ?Sized> {
+ spin_lock: Opaque<bindings::raw_spinlock>,
+
+ // Spinlocks are architecture-defined. So we conservatively require them to be pinned in case
+ // some architecture uses self-references now or in the future.
+ _pin: PhantomPinned,
+
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `RawSpinLock` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send> Send for RawSpinLock<T> {}
+
+// SAFETY: `RawSpinLock` serialises the interior mutability it provides, so it is `Sync` as long as
+// the data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for RawSpinLock<T> {}
+
+impl<T> RawSpinLock<T> {
+ /// Constructs a new raw spinlock.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call [`RawSpinLock::init_lock`] before using the raw spinlock.
+ pub const unsafe fn new(t: T) -> Self {
+ Self {
+ spin_lock: Opaque::uninit(),
+ data: UnsafeCell::new(t),
+ _pin: PhantomPinned,
+ }
+ }
+}
+
+impl<T: ?Sized> RawSpinLock<T> {
+ /// Locks the raw spinlock and gives the caller access to the data protected by it. Only one
+ /// thread at a time is allowed to access the protected data.
+ pub fn lock(&self) -> Guard<'_, Self, WriteLock> {
+ let ctx = <Self as Lock<WriteLock>>::lock_noguard(self);
+ // SAFETY: The raw spinlock was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+
+ /// Locks the raw spinlock and gives the caller access to the data protected by it.
+ /// Additionally it disables interrupts (if they are enabled).
+ ///
+ /// When the lock in unlocked, the interrupt state (enabled/disabled) is restored.
+ pub fn lock_irqdisable(&self) -> Guard<'_, Self, DisabledInterrupts> {
+ let ctx = <Self as Lock<DisabledInterrupts>>::lock_noguard(self);
+ // SAFETY: The raw spinlock was just acquired.
+ unsafe { Guard::new(self, ctx) }
+ }
+}
+
+impl<T> LockFactory for RawSpinLock<T> {
+ type LockedType<U> = RawSpinLock<U>;
+
+ unsafe fn new_lock<U>(data: U) -> RawSpinLock<U> {
+ // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+ unsafe { RawSpinLock::new(data) }
+ }
+}
+
+impl<T> LockIniter for RawSpinLock<T> {
+ unsafe fn init_lock(
+ self: Pin<&mut Self>,
+ name: &'static CStr,
+ key: *mut bindings::lock_class_key,
+ ) {
+ unsafe { bindings::_raw_spin_lock_init(self.spin_lock.get(), name.as_char_ptr(), key) };
+ }
+}
+
+// SAFETY: The underlying kernel `raw_spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for RawSpinLock<T> {
+ type Inner = T;
+ type GuardContext = EmptyGuardContext;
+
+ fn lock_noguard(&self) -> EmptyGuardContext {
+ // SAFETY: `spin_lock` points to valid memory.
+ unsafe { bindings::raw_spin_lock(self.spin_lock.get()) };
+ EmptyGuardContext
+ }
+
+ unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+ // SAFETY: The safety requirements of the function ensure that the raw spinlock is owned by
+ // the caller.
+ unsafe { bindings::raw_spin_unlock(self.spin_lock.get()) };
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
+
+// SAFETY: The underlying kernel `raw_spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock<DisabledInterrupts> for RawSpinLock<T> {
+ type Inner = T;
+ type GuardContext = c_types::c_ulong;
+
+ fn lock_noguard(&self) -> c_types::c_ulong {
+ // SAFETY: `spin_lock` points to valid memory.
+ unsafe { bindings::raw_spin_lock_irqsave(self.spin_lock.get()) }
+ }
+
+ unsafe fn unlock(&self, ctx: &mut c_types::c_ulong) {
+ // SAFETY: The safety requirements of the function ensure that the raw spinlock is owned by
+ // the caller.
+ unsafe { bindings::raw_spin_unlock_irqrestore(self.spin_lock.get(), *ctx) };
+ }
+
+ fn locked_data(&self) -> &UnsafeCell<T> {
+ &self.data
+ }
+}
--
2.35.3
This crate contains all the procedural macros ("proc macros")
shared by all the kernel.
Procedural macros allow to create syntax extensions. They run at
compile-time and can consume as well as produce Rust syntax.
For instance, the `module!` macro that is used by Rust modules
is implemented here. It allows to easily declare the equivalent
information to the `MODULE_*` macros in C modules, e.g.:
module! {
type: RustMinimal,
name: b"rust_minimal",
author: b"Rust for Linux Contributors",
description: b"Rust minimal sample",
license: b"GPL v2",
}
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Finn Behrens <[email protected]>
Signed-off-by: Finn Behrens <[email protected]>
Co-developed-by: Adam Bratschi-Kaye <[email protected]>
Signed-off-by: Adam Bratschi-Kaye <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Sumera Priyadarsini <[email protected]>
Signed-off-by: Sumera Priyadarsini <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Matthew Bakhtiari <[email protected]>
Signed-off-by: Matthew Bakhtiari <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
rust/macros/helpers.rs | 79 ++++++
rust/macros/lib.rs | 94 ++++++
rust/macros/module.rs | 631 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 804 insertions(+)
create mode 100644 rust/macros/helpers.rs
create mode 100644 rust/macros/lib.rs
create mode 100644 rust/macros/module.rs
diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
new file mode 100644
index 000000000000..ad210563e5a6
--- /dev/null
+++ b/rust/macros/helpers.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Group, TokenTree};
+
+pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
+ if let Some(TokenTree::Ident(ident)) = it.next() {
+ Some(ident.to_string())
+ } else {
+ None
+ }
+}
+
+pub(crate) fn try_literal(it: &mut token_stream::IntoIter) -> Option<String> {
+ if let Some(TokenTree::Literal(literal)) = it.next() {
+ Some(literal.to_string())
+ } else {
+ None
+ }
+}
+
+pub(crate) fn try_byte_string(it: &mut token_stream::IntoIter) -> Option<String> {
+ try_literal(it).and_then(|byte_string| {
+ if byte_string.starts_with("b\"") && byte_string.ends_with('\"') {
+ Some(byte_string[2..byte_string.len() - 1].to_string())
+ } else {
+ None
+ }
+ })
+}
+
+pub(crate) fn expect_ident(it: &mut token_stream::IntoIter) -> String {
+ try_ident(it).expect("Expected Ident")
+}
+
+pub(crate) fn expect_punct(it: &mut token_stream::IntoIter) -> char {
+ if let TokenTree::Punct(punct) = it.next().expect("Reached end of token stream for Punct") {
+ punct.as_char()
+ } else {
+ panic!("Expected Punct");
+ }
+}
+
+pub(crate) fn expect_literal(it: &mut token_stream::IntoIter) -> String {
+ try_literal(it).expect("Expected Literal")
+}
+
+pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group {
+ if let TokenTree::Group(group) = it.next().expect("Reached end of token stream for Group") {
+ group
+ } else {
+ panic!("Expected Group");
+ }
+}
+
+pub(crate) fn expect_byte_string(it: &mut token_stream::IntoIter) -> String {
+ try_byte_string(it).expect("Expected byte string")
+}
+
+pub(crate) fn expect_end(it: &mut token_stream::IntoIter) {
+ if it.next().is_some() {
+ panic!("Expected end");
+ }
+}
+
+pub(crate) fn get_literal(it: &mut token_stream::IntoIter, expected_name: &str) -> String {
+ assert_eq!(expect_ident(it), expected_name);
+ assert_eq!(expect_punct(it), ':');
+ let literal = expect_literal(it);
+ assert_eq!(expect_punct(it), ',');
+ literal
+}
+
+pub(crate) fn get_byte_string(it: &mut token_stream::IntoIter, expected_name: &str) -> String {
+ assert_eq!(expect_ident(it), expected_name);
+ assert_eq!(expect_punct(it), ':');
+ let byte_string = expect_byte_string(it);
+ assert_eq!(expect_punct(it), ',');
+ byte_string
+}
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
new file mode 100644
index 000000000000..39e8b07537a0
--- /dev/null
+++ b/rust/macros/lib.rs
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Crate for all kernel procedural macros.
+
+mod helpers;
+mod module;
+
+use proc_macro::TokenStream;
+
+/// Declares a kernel module.
+///
+/// The `type` argument should be a type which implements the [`Module`]
+/// trait. Also accepts various forms of kernel metadata.
+///
+/// C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+///
+/// [`Module`]: ../kernel/trait.Module.html
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// module!{
+/// type: MyModule,
+/// name: b"my_kernel_module",
+/// author: b"Rust for Linux Contributors",
+/// description: b"My very own kernel module!",
+/// license: b"GPL v2",
+/// params: {
+/// my_i32: i32 {
+/// default: 42,
+/// permissions: 0o000,
+/// description: b"Example of i32",
+/// },
+/// writeable_i32: i32 {
+/// default: 42,
+/// permissions: 0o644,
+/// description: b"Example of i32",
+/// },
+/// },
+/// }
+///
+/// struct MyModule;
+///
+/// impl kernel::Module for MyModule {
+/// fn init() -> Result<Self> {
+/// // If the parameter is writeable, then the kparam lock must be
+/// // taken to read the parameter:
+/// {
+/// let lock = THIS_MODULE.kernel_param_lock();
+/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
+/// }
+/// // If the parameter is read only, it can be read without locking
+/// // the kernel parameters:
+/// pr_info!("i32 param is: {}\n", my_i32.read());
+/// Ok(Self)
+/// }
+/// }
+/// ```
+///
+/// # Supported argument types
+/// - `type`: type which implements the [`Module`] trait (required).
+/// - `name`: byte array of the name of the kernel module (required).
+/// - `author`: byte array of the author of the kernel module.
+/// - `description`: byte array of the description of the kernel module.
+/// - `license`: byte array of the license of the kernel module (required).
+/// - `alias`: byte array of alias name of the kernel module.
+/// - `alias_rtnl_link`: byte array of the `rtnl_link_alias` of the kernel module (mutually exclusive with `alias`).
+/// - `params`: parameters for the kernel module, as described below.
+///
+/// # Supported parameter types
+///
+/// - `bool`: Corresponds to C `bool` param type.
+/// - `i8`: No equivalent C param type.
+/// - `u8`: Corresponds to C `char` param type.
+/// - `i16`: Corresponds to C `short` param type.
+/// - `u16`: Corresponds to C `ushort` param type.
+/// - `i32`: Corresponds to C `int` param type.
+/// - `u32`: Corresponds to C `uint` param type.
+/// - `i64`: No equivalent C param type.
+/// - `u64`: Corresponds to C `ullong` param type.
+/// - `isize`: No equivalent C param type.
+/// - `usize`: No equivalent C param type.
+/// - `str`: Corresponds to C `charp` param type. Reading returns a byte slice.
+/// - `ArrayParam<T,N>`: Corresponds to C parameters created using `module_param_array`. An array
+/// of `T`'s of length at **most** `N`.
+///
+/// `invbool` is unsupported: it was only ever used in a few modules.
+/// Consider using a `bool` and inverting the logic instead.
+#[proc_macro]
+pub fn module(ts: TokenStream) -> TokenStream {
+ module::module(ts)
+}
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
new file mode 100644
index 000000000000..323934b24e7f
--- /dev/null
+++ b/rust/macros/module.rs
@@ -0,0 +1,631 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Delimiter, Group, Literal, TokenStream, TokenTree};
+
+use crate::helpers::*;
+
+#[derive(Clone, PartialEq)]
+enum ParamType {
+ Ident(String),
+ Array { vals: String, max_length: usize },
+}
+
+fn expect_array_fields(it: &mut token_stream::IntoIter) -> ParamType {
+ assert_eq!(expect_punct(it), '<');
+ let vals = expect_ident(it);
+ assert_eq!(expect_punct(it), ',');
+ let max_length_str = expect_literal(it);
+ let max_length = max_length_str
+ .parse::<usize>()
+ .expect("Expected usize length");
+ assert_eq!(expect_punct(it), '>');
+ ParamType::Array { vals, max_length }
+}
+
+fn expect_type(it: &mut token_stream::IntoIter) -> ParamType {
+ if let TokenTree::Ident(ident) = it
+ .next()
+ .expect("Reached end of token stream for param type")
+ {
+ match ident.to_string().as_ref() {
+ "ArrayParam" => expect_array_fields(it),
+ _ => ParamType::Ident(ident.to_string()),
+ }
+ } else {
+ panic!("Expected Param Type")
+ }
+}
+
+struct ModInfoBuilder<'a> {
+ module: &'a str,
+ counter: usize,
+ buffer: String,
+}
+
+impl<'a> ModInfoBuilder<'a> {
+ fn new(module: &'a str) -> Self {
+ ModInfoBuilder {
+ module,
+ counter: 0,
+ buffer: String::new(),
+ }
+ }
+
+ fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
+ use std::fmt::Write;
+
+ let string = if builtin {
+ // Built-in modules prefix their modinfo strings by `module.`.
+ format!(
+ "{module}.{field}={content}\0",
+ module = self.module,
+ field = field,
+ content = content
+ )
+ } else {
+ // Loadable modules' modinfo strings go as-is.
+ format!("{field}={content}\0", field = field, content = content)
+ };
+
+ write!(
+ &mut self.buffer,
+ "
+ {cfg}
+ #[doc(hidden)]
+ #[link_section = \".modinfo\"]
+ #[used]
+ pub static __{module}_{counter}: [u8; {length}] = *{string};
+ ",
+ cfg = if builtin {
+ "#[cfg(not(MODULE))]"
+ } else {
+ "#[cfg(MODULE)]"
+ },
+ module = self.module,
+ counter = self.counter,
+ length = string.len(),
+ string = Literal::byte_string(string.as_bytes()),
+ )
+ .unwrap();
+
+ self.counter += 1;
+ }
+
+ fn emit_only_builtin(&mut self, field: &str, content: &str) {
+ self.emit_base(field, content, true)
+ }
+
+ fn emit_only_loadable(&mut self, field: &str, content: &str) {
+ self.emit_base(field, content, false)
+ }
+
+ fn emit(&mut self, field: &str, content: &str) {
+ self.emit_only_builtin(field, content);
+ self.emit_only_loadable(field, content);
+ }
+
+ fn emit_param(&mut self, field: &str, param: &str, content: &str) {
+ let content = format!("{param}:{content}", param = param, content = content);
+ self.emit(field, &content);
+ }
+}
+
+fn permissions_are_readonly(perms: &str) -> bool {
+ let (radix, digits) = if let Some(n) = perms.strip_prefix("0x") {
+ (16, n)
+ } else if let Some(n) = perms.strip_prefix("0o") {
+ (8, n)
+ } else if let Some(n) = perms.strip_prefix("0b") {
+ (2, n)
+ } else {
+ (10, perms)
+ };
+ match u32::from_str_radix(digits, radix) {
+ Ok(perms) => perms & 0o222 == 0,
+ Err(_) => false,
+ }
+}
+
+fn param_ops_path(param_type: &str) -> &'static str {
+ match param_type {
+ "bool" => "kernel::module_param::PARAM_OPS_BOOL",
+ "i8" => "kernel::module_param::PARAM_OPS_I8",
+ "u8" => "kernel::module_param::PARAM_OPS_U8",
+ "i16" => "kernel::module_param::PARAM_OPS_I16",
+ "u16" => "kernel::module_param::PARAM_OPS_U16",
+ "i32" => "kernel::module_param::PARAM_OPS_I32",
+ "u32" => "kernel::module_param::PARAM_OPS_U32",
+ "i64" => "kernel::module_param::PARAM_OPS_I64",
+ "u64" => "kernel::module_param::PARAM_OPS_U64",
+ "isize" => "kernel::module_param::PARAM_OPS_ISIZE",
+ "usize" => "kernel::module_param::PARAM_OPS_USIZE",
+ "str" => "kernel::module_param::PARAM_OPS_STR",
+ t => panic!("Unrecognized type {}", t),
+ }
+}
+
+fn try_simple_param_val(
+ param_type: &str,
+) -> Box<dyn Fn(&mut token_stream::IntoIter) -> Option<String>> {
+ match param_type {
+ "bool" => Box::new(try_ident),
+ "str" => Box::new(|param_it| {
+ try_byte_string(param_it)
+ .map(|s| format!("kernel::module_param::StringParam::Ref(b\"{}\")", s))
+ }),
+ _ => Box::new(try_literal),
+ }
+}
+
+fn get_default(param_type: &ParamType, param_it: &mut token_stream::IntoIter) -> String {
+ let try_param_val = match param_type {
+ ParamType::Ident(ref param_type)
+ | ParamType::Array {
+ vals: ref param_type,
+ max_length: _,
+ } => try_simple_param_val(param_type),
+ };
+ assert_eq!(expect_ident(param_it), "default");
+ assert_eq!(expect_punct(param_it), ':');
+ let default = match param_type {
+ ParamType::Ident(_) => try_param_val(param_it).expect("Expected default param value"),
+ ParamType::Array {
+ vals: _,
+ max_length: _,
+ } => {
+ let group = expect_group(param_it);
+ assert_eq!(group.delimiter(), Delimiter::Bracket);
+ let mut default_vals = Vec::new();
+ let mut it = group.stream().into_iter();
+
+ while let Some(default_val) = try_param_val(&mut it) {
+ default_vals.push(default_val);
+ match it.next() {
+ Some(TokenTree::Punct(punct)) => assert_eq!(punct.as_char(), ','),
+ None => break,
+ _ => panic!("Expected ',' or end of array default values"),
+ }
+ }
+
+ let mut default_array = "kernel::module_param::ArrayParam::create(&[".to_string();
+ default_array.push_str(
+ &default_vals
+ .iter()
+ .map(|val| val.to_string())
+ .collect::<Vec<String>>()
+ .join(","),
+ );
+ default_array.push_str("])");
+ default_array
+ }
+ };
+ assert_eq!(expect_punct(param_it), ',');
+ default
+}
+
+fn generated_array_ops_name(vals: &str, max_length: usize) -> String {
+ format!(
+ "__generated_array_ops_{vals}_{max_length}",
+ vals = vals,
+ max_length = max_length
+ )
+}
+
+#[derive(Debug, Default)]
+struct ModuleInfo {
+ type_: String,
+ license: String,
+ name: String,
+ author: Option<String>,
+ description: Option<String>,
+ alias: Option<String>,
+ params: Option<Group>,
+}
+
+impl ModuleInfo {
+ fn parse(it: &mut token_stream::IntoIter) -> Self {
+ let mut info = ModuleInfo::default();
+
+ const EXPECTED_KEYS: &[&str] = &[
+ "type",
+ "name",
+ "author",
+ "description",
+ "license",
+ "alias",
+ "alias_rtnl_link",
+ "params",
+ ];
+ const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
+ let mut seen_keys = Vec::new();
+
+ loop {
+ let key = match it.next() {
+ Some(TokenTree::Ident(ident)) => ident.to_string(),
+ Some(_) => panic!("Expected Ident or end"),
+ None => break,
+ };
+
+ if seen_keys.contains(&key) {
+ panic!(
+ "Duplicated key \"{}\". Keys can only be specified once.",
+ key
+ );
+ }
+
+ assert_eq!(expect_punct(it), ':');
+
+ match key.as_str() {
+ "type" => info.type_ = expect_ident(it),
+ "name" => info.name = expect_byte_string(it),
+ "author" => info.author = Some(expect_byte_string(it)),
+ "description" => info.description = Some(expect_byte_string(it)),
+ "license" => info.license = expect_byte_string(it),
+ "alias" => info.alias = Some(expect_byte_string(it)),
+ "alias_rtnl_link" => {
+ info.alias = Some(format!("rtnl-link-{}", expect_byte_string(it)))
+ }
+ "params" => info.params = Some(expect_group(it)),
+ _ => panic!(
+ "Unknown key \"{}\". Valid keys are: {:?}.",
+ key, EXPECTED_KEYS
+ ),
+ }
+
+ assert_eq!(expect_punct(it), ',');
+
+ seen_keys.push(key);
+ }
+
+ expect_end(it);
+
+ for key in REQUIRED_KEYS {
+ if !seen_keys.iter().any(|e| e == key) {
+ panic!("Missing required key \"{}\".", key);
+ }
+ }
+
+ let mut ordered_keys: Vec<&str> = Vec::new();
+ for key in EXPECTED_KEYS {
+ if seen_keys.iter().any(|e| e == key) {
+ ordered_keys.push(key);
+ }
+ }
+
+ if seen_keys != ordered_keys {
+ panic!(
+ "Keys are not ordered as expected. Order them like: {:?}.",
+ ordered_keys
+ );
+ }
+
+ info
+ }
+}
+
+pub(crate) fn module(ts: TokenStream) -> TokenStream {
+ let mut it = ts.into_iter();
+
+ let info = ModuleInfo::parse(&mut it);
+
+ let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
+ if let Some(author) = info.author {
+ modinfo.emit("author", &author);
+ }
+ if let Some(description) = info.description {
+ modinfo.emit("description", &description);
+ }
+ modinfo.emit("license", &info.license);
+ if let Some(alias) = info.alias {
+ modinfo.emit("alias", &alias);
+ }
+
+ // Built-in modules also export the `file` modinfo string.
+ let file =
+ std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
+ modinfo.emit_only_builtin("file", &file);
+
+ let mut array_types_to_generate = Vec::new();
+ if let Some(params) = info.params {
+ assert_eq!(params.delimiter(), Delimiter::Brace);
+
+ let mut it = params.stream().into_iter();
+
+ loop {
+ let param_name = match it.next() {
+ Some(TokenTree::Ident(ident)) => ident.to_string(),
+ Some(_) => panic!("Expected Ident or end"),
+ None => break,
+ };
+
+ assert_eq!(expect_punct(&mut it), ':');
+ let param_type = expect_type(&mut it);
+ let group = expect_group(&mut it);
+ assert_eq!(expect_punct(&mut it), ',');
+
+ assert_eq!(group.delimiter(), Delimiter::Brace);
+
+ let mut param_it = group.stream().into_iter();
+ let param_default = get_default(¶m_type, &mut param_it);
+ let param_permissions = get_literal(&mut param_it, "permissions");
+ let param_description = get_byte_string(&mut param_it, "description");
+ expect_end(&mut param_it);
+
+ // TODO: More primitive types.
+ // TODO: Other kinds: unsafes, etc.
+ let (param_kernel_type, ops): (String, _) = match param_type {
+ ParamType::Ident(ref param_type) => (
+ param_type.to_string(),
+ param_ops_path(param_type).to_string(),
+ ),
+ ParamType::Array {
+ ref vals,
+ max_length,
+ } => {
+ array_types_to_generate.push((vals.clone(), max_length));
+ (
+ format!("__rust_array_param_{}_{}", vals, max_length),
+ generated_array_ops_name(vals, max_length),
+ )
+ }
+ };
+
+ modinfo.emit_param("parmtype", ¶m_name, ¶m_kernel_type);
+ modinfo.emit_param("parm", ¶m_name, ¶m_description);
+ let param_type_internal = match param_type {
+ ParamType::Ident(ref param_type) => match param_type.as_ref() {
+ "str" => "kernel::module_param::StringParam".to_string(),
+ other => other.to_string(),
+ },
+ ParamType::Array {
+ ref vals,
+ max_length,
+ } => format!(
+ "kernel::module_param::ArrayParam<{vals}, {max_length}>",
+ vals = vals,
+ max_length = max_length
+ ),
+ };
+ let read_func = if permissions_are_readonly(¶m_permissions) {
+ format!(
+ "
+ fn read(&self) -> &<{param_type_internal} as kernel::module_param::ModuleParam>::Value {{
+ // SAFETY: Parameters do not need to be locked because they are read only or sysfs is not enabled.
+ unsafe {{ <{param_type_internal} as kernel::module_param::ModuleParam>::value(&__{name}_{param_name}_value) }}
+ }}
+ ",
+ name = info.name,
+ param_name = param_name,
+ param_type_internal = param_type_internal,
+ )
+ } else {
+ format!(
+ "
+ fn read<'lck>(&self, lock: &'lck kernel::KParamGuard) -> &'lck <{param_type_internal} as kernel::module_param::ModuleParam>::Value {{
+ // SAFETY: Parameters are locked by `KParamGuard`.
+ unsafe {{ <{param_type_internal} as kernel::module_param::ModuleParam>::value(&__{name}_{param_name}_value) }}
+ }}
+ ",
+ name = info.name,
+ param_name = param_name,
+ param_type_internal = param_type_internal,
+ )
+ };
+ let kparam = format!(
+ "
+ kernel::bindings::kernel_param__bindgen_ty_1 {{
+ arg: unsafe {{ &__{name}_{param_name}_value }} as *const _ as *mut kernel::c_types::c_void,
+ }},
+ ",
+ name = info.name,
+ param_name = param_name,
+ );
+ modinfo.buffer.push_str(
+ &format!(
+ "
+ static mut __{name}_{param_name}_value: {param_type_internal} = {param_default};
+
+ struct __{name}_{param_name};
+
+ impl __{name}_{param_name} {{ {read_func} }}
+
+ const {param_name}: __{name}_{param_name} = __{name}_{param_name};
+
+ // Note: the C macro that generates the static structs for the `__param` section
+ // asks for them to be `aligned(sizeof(void *))`. However, that was put in place
+ // in 2003 in commit 38d5b085d2 (\"[PATCH] Fix over-alignment problem on x86-64\")
+ // to undo GCC over-alignment of static structs of >32 bytes. It seems that is
+ // not the case anymore, so we simplify to a transparent representation here
+ // in the expectation that it is not needed anymore.
+ // TODO: Revisit this to confirm the above comment and remove it if it happened.
+ #[repr(transparent)]
+ struct __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param);
+
+ unsafe impl Sync for __{name}_{param_name}_RacyKernelParam {{
+ }}
+
+ #[cfg(not(MODULE))]
+ const __{name}_{param_name}_name: *const kernel::c_types::c_char = b\"{name}.{param_name}\\0\" as *const _ as *const kernel::c_types::c_char;
+
+ #[cfg(MODULE)]
+ const __{name}_{param_name}_name: *const kernel::c_types::c_char = b\"{param_name}\\0\" as *const _ as *const kernel::c_types::c_char;
+
+ #[link_section = \"__param\"]
+ #[used]
+ static __{name}_{param_name}_struct: __{name}_{param_name}_RacyKernelParam = __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param {{
+ name: __{name}_{param_name}_name,
+ // SAFETY: `__this_module` is constructed by the kernel at load time and will not be freed until the module is unloaded.
+ #[cfg(MODULE)]
+ mod_: unsafe {{ &kernel::bindings::__this_module as *const _ as *mut _ }},
+ #[cfg(not(MODULE))]
+ mod_: core::ptr::null_mut(),
+ ops: unsafe {{ &{ops} }} as *const kernel::bindings::kernel_param_ops,
+ perm: {permissions},
+ level: -1,
+ flags: 0,
+ __bindgen_anon_1: {kparam}
+ }});
+ ",
+ name = info.name,
+ param_type_internal = param_type_internal,
+ read_func = read_func,
+ param_default = param_default,
+ param_name = param_name,
+ ops = ops,
+ permissions = param_permissions,
+ kparam = kparam,
+ )
+ );
+ }
+ }
+
+ let mut generated_array_types = String::new();
+
+ for (vals, max_length) in array_types_to_generate {
+ let ops_name = generated_array_ops_name(&vals, max_length);
+ generated_array_types.push_str(&format!(
+ "
+ kernel::make_param_ops!(
+ {ops_name},
+ kernel::module_param::ArrayParam<{vals}, {{ {max_length} }}>
+ );
+ ",
+ ops_name = ops_name,
+ vals = vals,
+ max_length = max_length,
+ ));
+ }
+
+ format!(
+ "
+ /// The module name.
+ ///
+ /// Used by the printing macros, e.g. [`info!`].
+ const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
+
+ /// The \"Rust loadable module\" mark, for `scripts/is_rust_module.sh`.
+ //
+ // This may be best done another way later on, e.g. as a new modinfo
+ // key or a new section. For the moment, keep it simple.
+ #[cfg(MODULE)]
+ #[doc(hidden)]
+ #[used]
+ static __IS_RUST_MODULE: () = ();
+
+ static mut __MOD: Option<{type_}> = None;
+
+ // SAFETY: `__this_module` is constructed by the kernel at load time and will not be freed until the module is unloaded.
+ #[cfg(MODULE)]
+ static THIS_MODULE: kernel::ThisModule = unsafe {{ kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _) }};
+ #[cfg(not(MODULE))]
+ static THIS_MODULE: kernel::ThisModule = unsafe {{ kernel::ThisModule::from_ptr(core::ptr::null_mut()) }};
+
+ // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
+ #[cfg(MODULE)]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn init_module() -> kernel::c_types::c_int {{
+ __init()
+ }}
+
+ #[cfg(MODULE)]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn cleanup_module() {{
+ __exit()
+ }}
+
+ // Built-in modules are initialized through an initcall pointer
+ // and the identifiers need to be unique.
+ #[cfg(not(MODULE))]
+ #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
+ #[doc(hidden)]
+ #[link_section = \"{initcall_section}\"]
+ #[used]
+ pub static __{name}_initcall: extern \"C\" fn() -> kernel::c_types::c_int = __{name}_init;
+
+ #[cfg(not(MODULE))]
+ #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
+ core::arch::global_asm!(
+ r#\".section \"{initcall_section}\", \"a\"
+ __{name}_initcall:
+ .long __{name}_init - .
+ .previous
+ \"#
+ );
+
+ #[cfg(not(MODULE))]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn __{name}_init() -> kernel::c_types::c_int {{
+ __init()
+ }}
+
+ #[cfg(not(MODULE))]
+ #[doc(hidden)]
+ #[no_mangle]
+ pub extern \"C\" fn __{name}_exit() {{
+ __exit()
+ }}
+
+ fn __init() -> kernel::c_types::c_int {{
+ match <{type_} as kernel::Module>::init(kernel::c_str!(\"{name}\"), &THIS_MODULE) {{
+ Ok(m) => {{
+ unsafe {{
+ __MOD = Some(m);
+ }}
+ return 0;
+ }}
+ Err(e) => {{
+ return e.to_kernel_errno();
+ }}
+ }}
+ }}
+
+ fn __exit() {{
+ unsafe {{
+ // Invokes `drop()` on `__MOD`, which should be used for cleanup.
+ __MOD = None;
+ }}
+ }}
+
+ {modinfo}
+
+ {generated_array_types}
+ ",
+ type_ = info.type_,
+ name = info.name,
+ modinfo = modinfo.buffer,
+ generated_array_types = generated_array_types,
+ initcall_section = ".initcall6.init"
+ ).parse().expect("Error parsing formatted string into token stream.")
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn test_permissions_are_readonly() {
+ assert!(permissions_are_readonly("0b000000000"));
+ assert!(permissions_are_readonly("0o000"));
+ assert!(permissions_are_readonly("000"));
+ assert!(permissions_are_readonly("0x000"));
+
+ assert!(!permissions_are_readonly("0b111111111"));
+ assert!(!permissions_are_readonly("0o777"));
+ assert!(!permissions_are_readonly("511"));
+ assert!(!permissions_are_readonly("0x1ff"));
+
+ assert!(permissions_are_readonly("0o014"));
+ assert!(permissions_are_readonly("0o015"));
+
+ assert!(!permissions_are_readonly("0o214"));
+ assert!(!permissions_are_readonly("0o024"));
+ assert!(!permissions_are_readonly("0o012"));
+
+ assert!(!permissions_are_readonly("0o315"));
+ assert!(!permissions_are_readonly("0o065"));
+ assert!(!permissions_are_readonly("0o017"));
+ }
+}
--
2.35.3
The `generate_rust_analyzer.py` script generates the configuration
file (`rust-project.json`) for rust-analyzer.
rust-analyzer is a modular compiler frontend for the Rust language.
It provides an LSP server which can be used in editors such as
VS Code, Emacs or Vim.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Finn Behrens <[email protected]>
Signed-off-by: Finn Behrens <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Boris-Chengbiao Zhou <[email protected]>
Signed-off-by: Boris-Chengbiao Zhou <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
scripts/generate_rust_analyzer.py | 134 ++++++++++++++++++++++++++++++
1 file changed, 134 insertions(+)
create mode 100755 scripts/generate_rust_analyzer.py
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
new file mode 100755
index 000000000000..37c049fb18f2
--- /dev/null
+++ b/scripts/generate_rust_analyzer.py
@@ -0,0 +1,134 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""generate_rust_analyzer - Generates the `rust-project.json` file for `rust-analyzer`.
+"""
+
+import argparse
+import json
+import logging
+import pathlib
+import sys
+
+def generate_crates(srctree, objtree, sysroot_src):
+ # Generate the configuration list.
+ cfg = []
+ with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
+ for line in fd:
+ line = line.replace("--cfg=", "")
+ line = line.replace("\n", "")
+ cfg.append(line)
+
+ # Now fill the crates list -- dependencies need to come first.
+ #
+ # Avoid O(n^2) iterations by keeping a map of indexes.
+ crates = []
+ crates_indexes = {}
+
+ def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
+ crates_indexes[display_name] = len(crates)
+ crates.append({
+ "display_name": display_name,
+ "root_module": str(root_module),
+ "is_workspace_member": is_workspace_member,
+ "is_proc_macro": is_proc_macro,
+ "deps": [{"crate": crates_indexes[dep], "name": dep} for dep in deps],
+ "cfg": cfg,
+ "edition": "2021",
+ "env": {
+ "RUST_MODFILE": "This is only for rust-analyzer"
+ }
+ })
+
+ # First, the ones in `rust/` since they are a bit special.
+ append_crate(
+ "core",
+ sysroot_src / "core" / "src" / "lib.rs",
+ [],
+ is_workspace_member=False,
+ )
+
+ append_crate(
+ "compiler_builtins",
+ srctree / "rust" / "compiler_builtins.rs",
+ [],
+ )
+
+ append_crate(
+ "alloc",
+ srctree / "rust" / "alloc" / "lib.rs",
+ ["core", "compiler_builtins"],
+ )
+
+ append_crate(
+ "macros",
+ srctree / "rust" / "macros" / "lib.rs",
+ [],
+ is_proc_macro=True,
+ )
+ crates[-1]["proc_macro_dylib_path"] = "rust/libmacros.so"
+
+ append_crate(
+ "build_error",
+ srctree / "rust" / "build_error.rs",
+ ["core", "compiler_builtins"],
+ )
+
+ append_crate(
+ "kernel",
+ srctree / "rust" / "kernel" / "lib.rs",
+ ["core", "alloc", "macros", "build_error"],
+ cfg=cfg,
+ )
+ crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True))
+ crates[-1]["source"] = {
+ "include_dirs": [
+ str(srctree / "rust" / "kernel"),
+ str(objtree / "rust")
+ ],
+ "exclude_dirs": [],
+ }
+
+ # Then, the rest outside of `rust/`.
+ #
+ # We explicitly mention the top-level folders we want to cover.
+ for folder in ("samples", "drivers"):
+ for path in (srctree / folder).rglob("*.rs"):
+ logging.info("Checking %s", path)
+ name = path.name.replace(".rs", "")
+
+ # Skip those that are not crate roots.
+ if f"{name}.o" not in open(path.parent / "Makefile").read():
+ continue
+
+ logging.info("Adding %s", name)
+ append_crate(
+ name,
+ path,
+ ["core", "alloc", "kernel"],
+ cfg=cfg,
+ )
+
+ return crates
+
+def main():
+ parser = argparse.ArgumentParser()
+ parser.add_argument('--verbose', '-v', action='store_true')
+ parser.add_argument("srctree", type=pathlib.Path)
+ parser.add_argument("objtree", type=pathlib.Path)
+ parser.add_argument("sysroot_src", type=pathlib.Path)
+ args = parser.parse_args()
+
+ logging.basicConfig(
+ format="[%(asctime)s] [%(levelname)s] %(message)s",
+ level=logging.INFO if args.verbose else logging.WARNING
+ )
+
+ rust_project = {
+ "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src),
+ "sysroot_src": str(args.sysroot_src),
+ }
+
+ json.dump(rust_project, sys.stdout, sort_keys=True, indent=4)
+
+if __name__ == "__main__":
+ main()
--
2.35.3
On Sat, May 07, 2022 at 01:06:18AM -0700, Kees Cook wrote:
> On Sat, May 07, 2022 at 07:23:58AM +0200, Miguel Ojeda wrote:
> > ## Patch series status
> >
> > The Rust support is still to be considered experimental. However,
> > support is good enough that kernel developers can start working on the
> > Rust abstractions for subsystems and write drivers and other modules.
>
> I'd really like to see this landed for a few reasons:
>
> - It's under active development, and I'd rather review the changes
> "normally", incrementally, etc. Right now it can be hard to re-review
> some of the "mostly the same each version" patches in the series.
>
> - I'd like to break the catch-22 of "ask for a new driver to be
> written in rust but the rust support isn't landed" vs "the rust
> support isn't landed because there aren't enough drivers". It
> really feels like "release early, release often" is needed here;
> it's hard to develop against -next. :)
>
> Should we give it a try for this coming merge window?
I'm broadly in favour of that. It's just code, we can always drop it
again or fix it. There's sufficient development community around it
that it's hardly going to become abandonware.
Rust symbols can become quite long due to namespacing introduced
by modules, types, traits, generics, etc.
Increasing to 255 is not enough in some cases, and therefore
we need to introduce longer lengths to the symbol table.
In order to avoid increasing all lengths to 2 bytes (since most
of them are small, including many Rust ones), we use ULEB128 to
keep smaller symbols in 1 byte, with the rest in 2 bytes.
Reviewed-by: Kees Cook <[email protected]>
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Boqun Feng <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Co-developed-by: Matthew Wilcox <[email protected]>
Signed-off-by: Matthew Wilcox <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
This is a prerequisite patch, independently submitted at:
https://lore.kernel.org/lkml/[email protected]/
kernel/kallsyms.c | 26 ++++++++++++++++++++++----
scripts/kallsyms.c | 29 ++++++++++++++++++++++++++---
2 files changed, 48 insertions(+), 7 deletions(-)
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 79f2eb617a62..e8d2262ef2d2 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -69,12 +69,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off,
data = &kallsyms_names[off];
len = *data;
data++;
+ off++;
+
+ /* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
+ if ((len & 0x80) != 0) {
+ len = (len & 0x7F) | (*data << 7);
+ data++;
+ off++;
+ }
/*
* Update the offset to return the offset for the next symbol on
* the compressed stream.
*/
- off += len + 1;
+ off += len;
/*
* For every byte on the compressed symbol data, copy the table
@@ -127,7 +135,7 @@ static char kallsyms_get_symbol_type(unsigned int off)
static unsigned int get_symbol_offset(unsigned long pos)
{
const u8 *name;
- int i;
+ int i, len;
/*
* Use the closest marker we have. We have markers every 256 positions,
@@ -141,8 +149,18 @@ static unsigned int get_symbol_offset(unsigned long pos)
* so we just need to add the len to the current pointer for every
* symbol we wish to skip.
*/
- for (i = 0; i < (pos & 0xFF); i++)
- name = name + (*name) + 1;
+ for (i = 0; i < (pos & 0xFF); i++) {
+ len = *name;
+
+ /*
+ * If MSB is 1, it is a "big" symbol, so we need to look into
+ * the next byte (and skip it, too).
+ */
+ if ((len & 0x80) != 0)
+ len = ((len & 0x7F) | (name[1] << 7)) + 1;
+
+ name = name + len + 1;
+ }
return name - kallsyms_names;
}
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 82d6508bdf29..7e99799aa7b9 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -480,12 +480,35 @@ static void write_src(void)
if ((i & 0xFF) == 0)
markers[i >> 8] = off;
- printf("\t.byte 0x%02x", table[i]->len);
+ /* There cannot be any symbol of length zero. */
+ if (table[i]->len == 0) {
+ fprintf(stderr, "kallsyms failure: "
+ "unexpected zero symbol length\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
+ if (table[i]->len > 0x3FFF) {
+ fprintf(stderr, "kallsyms failure: "
+ "unexpected huge symbol length\n");
+ exit(EXIT_FAILURE);
+ }
+
+ /* Encode length with ULEB128. */
+ if (table[i]->len <= 0x7F) {
+ /* Most symbols use a single byte for the length. */
+ printf("\t.byte 0x%02x", table[i]->len);
+ off += table[i]->len + 1;
+ } else {
+ /* "Big" symbols use two bytes. */
+ printf("\t.byte 0x%02x, 0x%02x",
+ (table[i]->len & 0x7F) | 0x80,
+ (table[i]->len >> 7) & 0x7F);
+ off += table[i]->len + 2;
+ }
for (k = 0; k < table[i]->len; k++)
printf(", 0x%02x", table[i]->sym[k]);
printf("\n");
-
- off += table[i]->len + 1;
}
printf("\n");
--
2.35.3
From: Boqun Feng <[email protected]>
This makes it easier to update the size later on.
Furthermore, a static assert is added to ensure both are updated
when that happens. The relationship used is one that keeps the new
size (512+1) close to the original buffer size (500).
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Co-developed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
This is a prerequisite patch, independently submitted at:
https://lore.kernel.org/lkml/[email protected]/
scripts/kallsyms.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 8caabddf817c..82d6508bdf29 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -27,8 +27,18 @@
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
+#define _stringify_1(x) #x
+#define _stringify(x) _stringify_1(x)
+
#define KSYM_NAME_LEN 128
+/* A substantially bigger size than the current maximum. */
+#define KSYM_NAME_LEN_BUFFER 512
+_Static_assert(
+ KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
+ "Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
+);
+
struct sym_entry {
unsigned long long addr;
unsigned int len;
@@ -197,15 +207,15 @@ static void check_symbol_range(const char *sym, unsigned long long addr,
static struct sym_entry *read_symbol(FILE *in)
{
- char name[500], type;
+ char name[KSYM_NAME_LEN_BUFFER+1], type;
unsigned long long addr;
unsigned int len;
struct sym_entry *sym;
int rc;
- rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
+ rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name);
if (rc != 3) {
- if (rc != EOF && fgets(name, 500, in) == NULL)
+ if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
fprintf(stderr, "Read error or end of file.\n");
return NULL;
}
--
2.35.3
Having all the new files in place, we now enable Rust support
in the build system, including `Kconfig` entries related to Rust,
the Rust configuration printer, the target specification
generation script, the version detection script and a few
other bits.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Finn Behrens <[email protected]>
Signed-off-by: Finn Behrens <[email protected]>
Co-developed-by: Adam Bratschi-Kaye <[email protected]>
Signed-off-by: Adam Bratschi-Kaye <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Michael Ellerman <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Co-developed-by: Sven Van Asbroeck <[email protected]>
Signed-off-by: Sven Van Asbroeck <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Boris-Chengbiao Zhou <[email protected]>
Signed-off-by: Boris-Chengbiao Zhou <[email protected]>
Co-developed-by: Boqun Feng <[email protected]>
Signed-off-by: Boqun Feng <[email protected]>
Co-developed-by: Douglas Su <[email protected]>
Signed-off-by: Douglas Su <[email protected]>
Co-developed-by: Dariusz Sosnowski <[email protected]>
Signed-off-by: Dariusz Sosnowski <[email protected]>
Co-developed-by: Antonio Terceiro <[email protected]>
Signed-off-by: Antonio Terceiro <[email protected]>
Co-developed-by: Daniel Xu <[email protected]>
Signed-off-by: Daniel Xu <[email protected]>
Co-developed-by: Miguel Cano <[email protected]>
Signed-off-by: Miguel Cano <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
.gitignore | 5 +
.rustfmt.toml | 12 +
Makefile | 175 +++++++-
arch/Kconfig | 6 +
arch/arm/Kconfig | 1 +
arch/arm64/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/riscv/Kconfig | 1 +
arch/riscv/Makefile | 5 +
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 14 +
init/Kconfig | 45 ++-
lib/Kconfig.debug | 155 ++++++++
rust/.gitignore | 10 +
rust/Makefile | 397 +++++++++++++++++++
rust/bindgen_parameters | 17 +
scripts/.gitignore | 1 +
scripts/Kconfig.include | 6 +-
scripts/Makefile | 3 +
scripts/Makefile.build | 60 +++
scripts/Makefile.debug | 10 +
scripts/Makefile.host | 34 +-
scripts/Makefile.lib | 12 +
scripts/Makefile.modfinal | 8 +-
scripts/cc-version.sh | 12 +-
scripts/generate_rust_target.rs | 227 +++++++++++
scripts/is_rust_module.sh | 13 +
scripts/kconfig/confdata.c | 75 ++++
scripts/min-tool-version.sh | 6 +
scripts/rust-is-available-bindgen-libclang.h | 2 +
scripts/rust-is-available.sh | 158 ++++++++
31 files changed, 1450 insertions(+), 23 deletions(-)
create mode 100644 .rustfmt.toml
create mode 100644 rust/.gitignore
create mode 100644 rust/Makefile
create mode 100644 rust/bindgen_parameters
create mode 100644 scripts/generate_rust_target.rs
create mode 100755 scripts/is_rust_module.sh
create mode 100644 scripts/rust-is-available-bindgen-libclang.h
create mode 100755 scripts/rust-is-available.sh
diff --git a/.gitignore b/.gitignore
index 7afd412dadd2..48c68948f476 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,6 +37,7 @@
*.o
*.o.*
*.patch
+*.rmeta
*.s
*.so
*.so.dbg
@@ -96,6 +97,7 @@ modules.order
!.gitattributes
!.gitignore
!.mailmap
+!.rustfmt.toml
#
# Generated include files
@@ -161,3 +163,6 @@ x509.genkey
# Documentation toolchain
sphinx_*/
+
+# Rust analyzer configuration
+/rust-project.json
diff --git a/.rustfmt.toml b/.rustfmt.toml
new file mode 100644
index 000000000000..3de5cc497465
--- /dev/null
+++ b/.rustfmt.toml
@@ -0,0 +1,12 @@
+edition = "2021"
+newline_style = "Unix"
+
+# Unstable options that help catching some mistakes in formatting and that we may want to enable
+# when they become stable.
+#
+# They are kept here since they are useful to run from time to time.
+#format_code_in_doc_comments = true
+#reorder_impl_items = true
+#comment_width = 100
+#wrap_comments = true
+#normalize_comments = true
diff --git a/Makefile b/Makefile
index 9a820c525b86..d0837a13e9d3 100644
--- a/Makefile
+++ b/Makefile
@@ -120,6 +120,15 @@ endif
export KBUILD_CHECKSRC
+# Enable "clippy" (a linter) as part of the Rust compilation.
+#
+# Use 'make CLIPPY=1' to enable it.
+ifeq ("$(origin CLIPPY)", "command line")
+ KBUILD_CLIPPY := $(CLIPPY)
+endif
+
+export KBUILD_CLIPPY
+
# Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
# directory of external module to build. Setting M= takes precedence.
ifeq ("$(origin M)", "command line")
@@ -267,7 +276,7 @@ no-dot-config-targets := $(clean-targets) \
cscope gtags TAGS tags help% %docs check% coccicheck \
$(version_h) headers headers_% archheaders archscripts \
%asm-generic kernelversion %src-pkg dt_binding_check \
- outputmakefile
+ outputmakefile rustavailable rustfmt rustfmtcheck
# Installation targets should not require compiler. Unfortunately, vdso_install
# is an exception where build artifacts may be updated. This must be fixed.
no-compiler-targets := $(no-dot-config-targets) install dtbs_install \
@@ -436,6 +445,7 @@ else
HOSTCC = gcc
HOSTCXX = g++
endif
+HOSTRUSTC = rustc
KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
-O2 -fomit-frame-pointer -std=gnu11 \
@@ -443,8 +453,26 @@ KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
KBUILD_USERCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
KBUILD_USERLDFLAGS := $(USERLDFLAGS)
+# These flags apply to all Rust code in the tree, including the kernel and
+# host programs.
+export rust_common_flags := --edition=2021 \
+ -Zbinary_dep_depinfo=y \
+ -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \
+ -Dunreachable_pub -Dnon_ascii_idents \
+ -Wmissing_docs \
+ -Drustdoc::missing_crate_level_docs \
+ -Dclippy::correctness -Dclippy::style \
+ -Dclippy::suspicious -Dclippy::complexity \
+ -Dclippy::perf \
+ -Dclippy::let_unit_value -Dclippy::mut_mut \
+ -Dclippy::needless_bitwise_bool \
+ -Dclippy::needless_continue \
+ -Wclippy::dbg_macro
+
KBUILD_HOSTCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
+KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \
+ -Zallow-features= $(HOSTRUSTFLAGS)
KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
@@ -469,6 +497,12 @@ OBJDUMP = $(CROSS_COMPILE)objdump
READELF = $(CROSS_COMPILE)readelf
STRIP = $(CROSS_COMPILE)strip
endif
+RUSTC = rustc
+RUSTDOC = rustdoc
+RUSTFMT = rustfmt
+CLIPPY_DRIVER = clippy-driver
+BINDGEN = bindgen
+CARGO = cargo
PAHOLE = pahole
RESOLVE_BTFIDS = $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
LEX = flex
@@ -494,9 +528,11 @@ CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
-Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
NOSTDINC_FLAGS :=
CFLAGS_MODULE =
+RUSTFLAGS_MODULE =
AFLAGS_MODULE =
LDFLAGS_MODULE =
CFLAGS_KERNEL =
+RUSTFLAGS_KERNEL =
AFLAGS_KERNEL =
LDFLAGS_vmlinux =
@@ -525,15 +561,42 @@ KBUILD_CFLAGS := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
-Werror=return-type -Wno-format-security \
-std=gnu11
KBUILD_CPPFLAGS := -D__KERNEL__
+KBUILD_RUSTFLAGS := $(rust_common_flags) \
+ --target=$(objtree)/rust/target.json \
+ -Cpanic=abort -Cembed-bitcode=n -Clto=n \
+ -Cforce-unwind-tables=n -Ccodegen-units=1 \
+ -Csymbol-mangling-version=v0 \
+ -Crelocation-model=static \
+ -Zfunction-sections=n \
+ -Dclippy::float_arithmetic
+
KBUILD_AFLAGS_KERNEL :=
KBUILD_CFLAGS_KERNEL :=
+KBUILD_RUSTFLAGS_KERNEL :=
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
+KBUILD_RUSTFLAGS_MODULE := --cfg MODULE
KBUILD_LDFLAGS_MODULE :=
KBUILD_LDFLAGS :=
CLANG_FLAGS :=
+ifeq ($(KBUILD_CLIPPY),1)
+ RUSTC_OR_CLIPPY_QUIET := CLIPPY
+ RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER)
+else
+ RUSTC_OR_CLIPPY_QUIET := RUSTC
+ RUSTC_OR_CLIPPY = $(RUSTC)
+endif
+
+ifdef RUST_LIB_SRC
+ export RUST_LIB_SRC
+endif
+
+export RUSTC_BOOTSTRAP := 1
+
export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
+export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
+export HOSTRUSTC KBUILD_HOSTRUSTFLAGS
export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
@@ -542,9 +605,10 @@ export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
+export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
-export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
-export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
+export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE
+export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL
export PAHOLE_FLAGS
# Files to ignore in find ... statements
@@ -725,7 +789,7 @@ $(KCONFIG_CONFIG):
#
# Do not use $(call cmd,...) here. That would suppress prompts from syncconfig,
# so you cannot notice that Kconfig is waiting for the user input.
-%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG)
+%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG)
$(Q)$(kecho) " SYNC $@"
$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
else # !may-sync-config
@@ -754,12 +818,28 @@ KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
KBUILD_CFLAGS += -O2
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 2
else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
KBUILD_CFLAGS += -O3
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := 3
else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
KBUILD_CFLAGS += -Os
+KBUILD_RUSTFLAGS_OPT_LEVEL_MAP := s
endif
+# Always set `debug-assertions` and `overflow-checks` because their default
+# depends on `opt-level` and `debug-assertions`, respectively.
+KBUILD_RUSTFLAGS += -Cdebug-assertions=$(if $(CONFIG_RUST_DEBUG_ASSERTIONS),y,n)
+KBUILD_RUSTFLAGS += -Coverflow-checks=$(if $(CONFIG_RUST_OVERFLOW_CHECKS),y,n)
+KBUILD_RUSTFLAGS += -Copt-level=$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C),$(KBUILD_RUSTFLAGS_OPT_LEVEL_MAP))$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_0),0)$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_1),1)$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_2),2)$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_3),3)$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_S),s)$\
+ $(if $(CONFIG_RUST_OPT_LEVEL_Z),z)
+
# Tell gcc to never replace conditional load with a non-conditional one
ifdef CONFIG_CC_IS_GCC
# gcc-10 renamed --param=allow-store-data-races=0 to
@@ -789,6 +869,9 @@ KBUILD_CFLAGS += $(stackp-flags-y)
KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
+KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
+KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y)
+
ifdef CONFIG_CC_IS_CLANG
KBUILD_CPPFLAGS += -Qunused-arguments
# The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
@@ -806,12 +889,15 @@ KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
ifdef CONFIG_FRAME_POINTER
KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
+KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
else
# Some targets (ARM with Thumb2, for example), can't be built with frame
# pointers. For those, we don't have FUNCTION_TRACER automatically
# select FRAME_POINTER. However, FUNCTION_TRACER adds -pg, and this is
# incompatible with -fomit-frame-pointer with current GCC, so we don't use
# -fomit-frame-pointer with FUNCTION_TRACER.
+# In the Rust target specification, "frame-pointer" is set explicitly
+# to "may-omit".
ifndef CONFIG_FUNCTION_TRACER
KBUILD_CFLAGS += -fomit-frame-pointer
endif
@@ -876,8 +962,10 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH
KBUILD_CFLAGS += -fno-inline-functions-called-once
endif
+# `rustc`'s `-Zfunction-sections` applies to data too (as of 1.59.0).
ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
+KBUILD_RUSTFLAGS_KERNEL += -Zfunction-sections=y
LDFLAGS_vmlinux += --gc-sections
endif
@@ -1019,10 +1107,11 @@ include $(addprefix $(srctree)/, $(include-y))
# Do not add $(call cc-option,...) below this line. When you build the kernel
# from the clean source tree, the GCC plugins do not exist at this point.
-# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
+# Add user supplied CPPFLAGS, AFLAGS, CFLAGS and RUSTFLAGS as the last assignments
KBUILD_CPPFLAGS += $(KCPPFLAGS)
KBUILD_AFLAGS += $(KAFLAGS)
KBUILD_CFLAGS += $(KCFLAGS)
+KBUILD_RUSTFLAGS += $(KRUSTFLAGS)
KBUILD_LDFLAGS_MODULE += --build-id=sha1
LDFLAGS_vmlinux += --build-id=sha1
@@ -1091,6 +1180,7 @@ export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps
ifeq ($(KBUILD_EXTMOD),)
core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/
core-$(CONFIG_BLOCK) += block/
+core-$(CONFIG_RUST) += rust/
vmlinux-dirs := $(patsubst %/,%,$(filter %/, \
$(core-y) $(core-m) $(drivers-y) $(drivers-m) \
@@ -1195,6 +1285,10 @@ prepare0: archprepare
# All the preparing..
prepare: prepare0
+ifdef CONFIG_RUST
+ $(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v
+ $(Q)$(MAKE) $(build)=rust
+endif
PHONY += remove-stale-files
remove-stale-files:
@@ -1483,7 +1577,7 @@ endif # CONFIG_MODULES
# Directories & files removed with 'make clean'
CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \
modules.builtin modules.builtin.modinfo modules.nsdeps \
- compile_commands.json .thinlto-cache
+ compile_commands.json .thinlto-cache rust/test rust/doc
# Directories & files removed with 'make mrproper'
MRPROPER_FILES += include/config include/generated \
@@ -1494,7 +1588,8 @@ MRPROPER_FILES += include/config include/generated \
certs/signing_key.pem \
certs/x509.genkey \
vmlinux-gdb.py \
- *.spec
+ *.spec \
+ rust/target.json rust/libmacros.so
# clean - Delete most, but leave enough to build external modules
#
@@ -1519,6 +1614,9 @@ $(mrproper-dirs):
mrproper: clean $(mrproper-dirs)
$(call cmd,rmfiles)
+ @find . $(RCS_FIND_IGNORE) \
+ \( -name '*.rmeta' \) \
+ -type f -print | xargs rm -f
# distclean
#
@@ -1606,6 +1704,23 @@ help:
@echo ' kselftest-merge - Merge all the config dependencies of'
@echo ' kselftest to existing .config.'
@echo ''
+ @echo 'Rust targets:'
+ @echo ' rustavailable - Checks whether the Rust toolchain is'
+ @echo ' available and, if not, explains why.'
+ @echo ' rustfmt - Reformat all the Rust code in the kernel'
+ @echo ' rustfmtcheck - Checks if all the Rust code in the kernel'
+ @echo ' is formatted, printing a diff otherwise.'
+ @echo ' rustdoc - Generate Rust documentation'
+ @echo ' (requires kernel .config)'
+ @echo ' rusttest - Runs the Rust tests'
+ @echo ' (requires kernel .config; downloads external repos)'
+ @echo ' rust-analyzer - Generate rust-project.json rust-analyzer support file'
+ @echo ' (requires kernel .config)'
+ @echo ' dir/file.[os] - Build specified target only'
+ @echo ' dir/file.i - Build macro expanded source, similar to C preprocessing'
+ @echo ' (run with RUSTFMT=n to skip reformatting if needed)'
+ @echo ' dir/file.ll - Build the LLVM assembly file'
+ @echo ''
@$(if $(dtstree), \
echo 'Devicetree:'; \
echo '* dtbs - Build device tree blobs for enabled boards'; \
@@ -1677,6 +1792,52 @@ PHONY += $(DOC_TARGETS)
$(DOC_TARGETS):
$(Q)$(MAKE) $(build)=Documentation $@
+
+# Rust targets
+# ---------------------------------------------------------------------------
+
+# "Is Rust available?" target
+PHONY += rustavailable
+rustavailable:
+ $(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v && echo >&2 "Rust is available!"
+
+# Documentation target
+#
+# Using the singular to avoid running afoul of `no-dot-config-targets`.
+PHONY += rustdoc
+rustdoc: prepare
+ $(Q)$(MAKE) $(build)=rust $@
+
+# Testing target
+PHONY += rusttest
+rusttest: prepare
+ $(Q)$(MAKE) $(build)=rust $@
+
+# Formatting targets
+PHONY += rustfmt rustfmtcheck
+
+# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream.
+#
+# We match using absolute paths since `find` does not resolve them
+# when matching, which is a problem when e.g. `srctree` is `..`.
+# We `grep` afterwards in order to remove the directory entry itself.
+rustfmt:
+ $(Q)find $(abs_srctree) -type f -name '*.rs' \
+ -o -path $(abs_srctree)/rust/alloc -prune \
+ -o -path $(abs_objtree)/rust/test -prune \
+ | grep -Fv $(abs_srctree)/rust/alloc \
+ | grep -Fv $(abs_objtree)/rust/test \
+ | grep -Fv generated \
+ | xargs $(RUSTFMT) $(rustfmt_flags)
+
+rustfmtcheck: rustfmt_flags = --check
+rustfmtcheck: rustfmt
+
+# IDE support targets
+PHONY += rust-analyzer
+rust-analyzer:
+ $(Q)$(MAKE) $(build)=rust $@
+
# Misc
# ---------------------------------------------------------------------------
diff --git a/arch/Kconfig b/arch/Kconfig
index 31c4fdc4a4ba..89d27b2a86dd 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -344,6 +344,12 @@ config HAVE_RSEQ
This symbol should be selected by an architecture if it
supports an implementation of restartable sequences.
+config HAVE_RUST
+ bool
+ help
+ This symbol should be selected by an architecture if it
+ supports Rust.
+
config HAVE_FUNCTION_ARG_ACCESS_API
bool
help
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2e8091e2d8a8..1d0005080aeb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -116,6 +116,7 @@ config ARM
select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RSEQ
+ select HAVE_RUST if CPU_32v6 || CPU_32v6K
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UID16
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 20ea89d9ac2f..308cff85f5cb 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -198,6 +198,7 @@ config ARM64
select HAVE_FUNCTION_ARG_ACCESS_API
select MMU_GATHER_RCU_TABLE_FREE
select HAVE_RSEQ
+ select HAVE_RUST
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KPROBES
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 174edabb74fa..ffbad38204b9 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -239,6 +239,7 @@ config PPC
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE
select HAVE_RSEQ
+ select HAVE_RUST if PPC64 && CPU_LITTLE_ENDIAN
select HAVE_SETUP_PER_CPU_AREA if PPC64
select HAVE_SOFTIRQ_ON_OWN_STACK
select HAVE_STACKPROTECTOR if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 00fd9c548f26..63f7258984f3 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -101,6 +101,7 @@ config RISCV
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_REGS_AND_STACK_ACCESS_API
+ select HAVE_RUST if 64BIT
select HAVE_FUNCTION_ARG_ACCESS_API
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 7d81102cffd4..663ae53b5597 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -26,6 +26,8 @@ ifeq ($(CONFIG_ARCH_RV64I),y)
KBUILD_CFLAGS += -mabi=lp64
KBUILD_AFLAGS += -mabi=lp64
+ KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv64
+
KBUILD_LDFLAGS += -melf64lriscv
else
BITS := 32
@@ -33,6 +35,9 @@ else
KBUILD_CFLAGS += -mabi=ilp32
KBUILD_AFLAGS += -mabi=ilp32
+
+ KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv32
+
KBUILD_LDFLAGS += -melf32lriscv
endif
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4bed3abf444d..8d4e30f07a7d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -252,6 +252,7 @@ config X86
select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION
select HAVE_PREEMPT_DYNAMIC_CALL
select HAVE_RSEQ
+ select HAVE_RUST if X86_64
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UNSTABLE_SCHED_CLOCK
select HAVE_USER_RETURN_NOTIFIER
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 63d50f65b828..5ac9b324751d 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -21,6 +21,8 @@ ifdef CONFIG_CC_IS_CLANG
RETPOLINE_CFLAGS := -mretpoline-external-thunk
RETPOLINE_VDSO_CFLAGS := -mretpoline
endif
+RETPOLINE_RUSTFLAGS := -Ctarget-feature=+retpoline-external-thunk
+
export RETPOLINE_CFLAGS
export RETPOLINE_VDSO_CFLAGS
@@ -61,6 +63,8 @@ export BITS
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
#
KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
+KBUILD_RUSTFLAGS += -Ctarget-feature=-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2
+KBUILD_RUSTFLAGS += -Ctarget-feature=-3dnow,-3dnowa,-avx,-avx2,+soft-float
ifeq ($(CONFIG_X86_KERNEL_IBT),y)
#
@@ -148,8 +152,17 @@ else
cflags-$(CONFIG_GENERIC_CPU) += -mtune=generic
KBUILD_CFLAGS += $(cflags-y)
+ rustflags-$(CONFIG_MK8) += -Ctarget-cpu=k8
+ rustflags-$(CONFIG_MPSC) += -Ctarget-cpu=nocona
+ rustflags-$(CONFIG_MCORE2) += -Ctarget-cpu=core2
+ rustflags-$(CONFIG_MATOM) += -Ctarget-cpu=atom
+ rustflags-$(CONFIG_GENERIC_CPU) += -Ztune-cpu=generic
+ KBUILD_RUSTFLAGS += $(rustflags-y)
+
KBUILD_CFLAGS += -mno-red-zone
KBUILD_CFLAGS += -mcmodel=kernel
+ KBUILD_RUSTFLAGS += -Cno-redzone=y
+ KBUILD_RUSTFLAGS += -Ccode-model=kernel
endif
#
@@ -185,6 +198,7 @@ ifdef CONFIG_RETPOLINE
ifndef CONFIG_CC_IS_CLANG
KBUILD_CFLAGS += -fno-jump-tables
endif
+ KBUILD_RUSTFLAGS += $(RETPOLINE_RUSTFLAGS)
endif
ifdef CONFIG_SLS
diff --git a/init/Kconfig b/init/Kconfig
index ddcbefe535e9..3457cf596588 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -60,6 +60,17 @@ config LLD_VERSION
default $(ld-version) if LD_IS_LLD
default 0
+config RUST_IS_AVAILABLE
+ def_bool $(success,$(srctree)/scripts/rust-is-available.sh)
+ help
+ This shows whether a suitable Rust toolchain is available (found).
+
+ Please see Documentation/rust/quick-start.rst for instructions on how
+ to satify the build requirements of Rust support.
+
+ In particular, the Makefile target 'rustavailable' is useful to check
+ why the Rust toolchain is not being detected.
+
config CC_CAN_LINK
bool
default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
@@ -146,7 +157,8 @@ config WERROR
default COMPILE_TEST
help
A kernel build should not cause any compiler warnings, and this
- enables the '-Werror' flag to enforce that rule by default.
+ enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
+ to enforce that rule by default.
However, if you have a new (or very old) compiler with odd and
unusual warnings, or you have some architecture with problems,
@@ -2045,6 +2057,37 @@ config PROFILING
Say Y here to enable the extended profiling support mechanisms used
by profilers.
+config RUST
+ bool "Rust support"
+ depends on HAVE_RUST
+ depends on RUST_IS_AVAILABLE
+ depends on !MODVERSIONS
+ depends on !GCC_PLUGINS
+ depends on !DEBUG_INFO_BTF
+ select CONSTRUCTORS
+ help
+ Enables Rust support in the kernel.
+
+ This allows other Rust-related options, like drivers written in Rust,
+ to be selected.
+
+ It is also required to be able to load external kernel modules
+ written in Rust.
+
+ See Documentation/rust/ for more information.
+
+ If unsure, say N.
+
+config RUSTC_VERSION_TEXT
+ string
+ depends on RUST
+ default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
+
+config BINDGEN_VERSION_TEXT
+ string
+ depends on RUST
+ default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
+
#
# Place an empty function call at each tracepoint site. Can be
# dynamically changed for a probe function.
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 075cd25363ac..bfc28f52b603 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2760,6 +2760,161 @@ config HYPERV_TESTING
endmenu # "Kernel Testing and Coverage"
+menu "Rust hacking"
+
+config RUST_DEBUG_ASSERTIONS
+ bool "Debug assertions"
+ depends on RUST
+ help
+ Enables rustc's `-Cdebug-assertions` codegen option.
+
+ This flag lets you turn `cfg(debug_assertions)` conditional
+ compilation on or off. This can be used to enable extra debugging
+ code in development but not in production. For example, it controls
+ the behavior of the standard library's `debug_assert!` macro.
+
+ Note that this will apply to all Rust code, including `core`.
+
+ If unsure, say N.
+
+config RUST_OVERFLOW_CHECKS
+ bool "Overflow checks"
+ default y
+ depends on RUST
+ help
+ Enables rustc's `-Coverflow-checks` codegen option.
+
+ This flag allows you to control the behavior of runtime integer
+ overflow. When overflow-checks are enabled, a Rust panic will occur
+ on overflow.
+
+ Note that this will apply to all Rust code, including `core`.
+
+ If unsure, say Y.
+
+choice
+ prompt "Optimization level"
+ default RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C
+ depends on RUST
+ help
+ Controls rustc's `-Copt-level` codegen option.
+
+ This flag controls the optimization level.
+
+ If unsure, say "Similar as chosen for C".
+
+config RUST_OPT_LEVEL_SIMILAR_AS_CHOSEN_FOR_C
+ bool "Similar as chosen for C"
+ help
+ This choice will pick a similar optimization level as chosen in
+ the "Compiler optimization level" for C:
+
+ -O2 is currently mapped to -Copt-level=2
+ -O3 is currently mapped to -Copt-level=3
+ -Os is currently mapped to -Copt-level=s
+
+ The mapping may change over time to follow the intended semantics
+ of the choice for C as sensibly as possible.
+
+ This is the default.
+
+config RUST_OPT_LEVEL_0
+ bool "No optimizations (-Copt-level=0)"
+ help
+ Not recommended for most purposes. It may come in handy for debugging
+ suspected optimizer bugs, unexpected undefined behavior, etc.
+
+ Note that this level will *not* enable debug assertions nor overflow
+ checks on its own (like it happens when interacting with rustc
+ directly). Use the corresponding configuration options to control
+ that instead, orthogonally.
+
+ Note this level may cause excessive stack usage, which can lead to stack
+ overflow and subsequent crashes.
+
+config RUST_OPT_LEVEL_1
+ bool "Basic optimizations (-Copt-level=1)"
+ help
+ Useful for debugging without getting too lost, but without
+ the overhead and boilerplate of no optimizations at all.
+
+ Note this level may cause excessive stack usage, which can lead to stack
+ overflow and subsequent crashes.
+
+config RUST_OPT_LEVEL_2
+ bool "Some optimizations (-Copt-level=2)"
+ help
+ The sensible choice in most cases.
+
+config RUST_OPT_LEVEL_3
+ bool "All optimizations (-Copt-level=3)"
+ help
+ Yet more performance (hopefully).
+
+config RUST_OPT_LEVEL_S
+ bool "Optimize for size (-Copt-level=s)"
+ help
+ Smaller kernel, ideally without too much performance loss.
+
+config RUST_OPT_LEVEL_Z
+ bool "Optimize for size, no loop vectorization (-Copt-level=z)"
+ help
+ Like the previous level, but also turn off loop vectorization.
+
+endchoice
+
+choice
+ prompt "Build-time assertions"
+ default RUST_BUILD_ASSERT_ALLOW if RUST_OPT_LEVEL_0
+ default RUST_BUILD_ASSERT_DENY if !RUST_OPT_LEVEL_0
+ depends on RUST
+ help
+ Controls how are `build_error!` and `build_assert!` handled during build.
+
+ If calls to them exist in the binary, it may indicate a violated invariant
+ or that the optimizer failed to verify the invariant during compilation.
+ You can choose to abort compilation or ignore them during build and let the
+ check be carried to runtime.
+
+ If optimizations are turned off, you cannot select "Deny".
+
+ If unsure, say "Deny".
+
+config RUST_BUILD_ASSERT_ALLOW
+ bool "Allow"
+ help
+ Unoptimized calls to `build_error!` will be converted to `panic!`
+ and checked at runtime.
+
+config RUST_BUILD_ASSERT_WARN
+ bool "Warn"
+ help
+ Unoptimized calls to `build_error!` will be converted to `panic!`
+ and checked at runtime, but warnings will be generated when building.
+
+config RUST_BUILD_ASSERT_DENY
+ bool "Deny"
+ depends on !RUST_OPT_LEVEL_0
+ help
+ Unoptimized calls to `build_error!` will abort compilation.
+
+endchoice
+
+config RUST_KERNEL_KUNIT_TEST
+ bool "KUnit test for the `kernel` crate" if !KUNIT_ALL_TESTS
+ depends on RUST && KUNIT=y
+ default KUNIT_ALL_TESTS
+ help
+ This builds the documentation tests of the `kernel` crate
+ as KUnit tests.
+
+ For more information on KUnit and unit tests in general,
+ please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+ If unsure, say N.
+
+endmenu # "Rust"
+
source "Documentation/Kconfig"
endmenu # Kernel hacking
diff --git a/rust/.gitignore b/rust/.gitignore
new file mode 100644
index 000000000000..89b602d91109
--- /dev/null
+++ b/rust/.gitignore
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+target.json
+bindings_generated.rs
+bindings_helpers_generated.rs
+exports_*_generated.h
+doctests_kernel_generated.rs
+doctests_kernel_generated_kunit.c
+doc/
+test/
diff --git a/rust/Makefile b/rust/Makefile
new file mode 100644
index 000000000000..6dad9a4ebcbc
--- /dev/null
+++ b/rust/Makefile
@@ -0,0 +1,397 @@
+# SPDX-License-Identifier: GPL-2.0
+
+always-$(CONFIG_RUST) += target.json
+no-clean-files += target.json
+
+obj-$(CONFIG_RUST) += core.o compiler_builtins.o
+always-$(CONFIG_RUST) += exports_core_generated.h
+
+# Missing prototypes are expected in the helpers since these are exported
+# for Rust only, thus there is no header nor prototypes.
+obj-$(CONFIG_RUST) += helpers.o
+CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations
+
+always-$(CONFIG_RUST) += libmacros.so
+no-clean-files += libmacros.so
+
+always-$(CONFIG_RUST) += bindings_generated.rs bindings_helpers_generated.rs
+obj-$(CONFIG_RUST) += alloc.o kernel.o
+always-$(CONFIG_RUST) += exports_alloc_generated.h exports_kernel_generated.h
+
+ifdef CONFIG_RUST_BUILD_ASSERT_DENY
+always-$(CONFIG_RUST) += build_error.o
+else
+obj-$(CONFIG_RUST) += build_error.o
+endif
+
+obj-$(CONFIG_RUST) += exports.o
+
+obj-$(CONFIG_RUST_KERNEL_KUNIT_TEST) += doctests_kernel_generated.o
+obj-$(CONFIG_RUST_KERNEL_KUNIT_TEST) += doctests_kernel_generated_kunit.o
+
+# Avoids running `$(RUSTC)` for the sysroot when it may not be available.
+ifdef CONFIG_RUST
+
+# `$(rust_flags)` is passed in case the user added `--sysroot`.
+rustc_sysroot := $(shell $(RUSTC) $(rust_flags) --print sysroot)
+rustc_host_target := $(shell $(RUSTC) --version --verbose | grep -F 'host: ' | cut -d' ' -f2)
+RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library
+
+ifeq ($(quiet),silent_)
+cargo_quiet=-q
+rust_test_quiet=-q
+rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
+else ifeq ($(quiet),quiet_)
+rust_test_quiet=-q
+rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
+else
+cargo_quiet=--verbose
+endif
+
+core-cfgs = \
+ --cfg no_fp_fmt_parse
+
+alloc-cfgs = \
+ --cfg no_global_oom_handling \
+ --cfg no_rc \
+ --cfg no_sync
+
+quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
+ cmd_rustdoc = \
+ OBJTREE=$(abspath $(objtree)) \
+ $(RUSTDOC) $(if $(rustdoc_host),$(rust_common_flags),$(rust_flags)) \
+ $(rustc_target_flags) -L$(objtree)/$(obj) \
+ --output $(objtree)/$(obj)/doc \
+ --crate-name $(subst rustdoc-,,$@) \
+ @$(objtree)/include/generated/rustc_cfg $<
+
+# The `html_logo_url` and `html_favicon_url` forms of the `doc` attribute
+# can be used to specify a custom logo. However:
+# - The given value is used as-is, thus it cannot be relative or a local file
+# (unlike the non-custom case) since the generated docs have subfolders.
+# - It requires adding it to every crate.
+# - It requires changing `core` which comes from the sysroot.
+#
+# Using `-Zcrate-attr` would solve the last two points, but not the first.
+# The https://github.com/rust-lang/rfcs/pull/3226 RFC suggests two new
+# command-like flags to solve the issue. Meanwhile, we use the non-custom case
+# and then retouch the generated files.
+rustdoc: rustdoc-core rustdoc-macros rustdoc-compiler_builtins \
+ rustdoc-alloc rustdoc-kernel
+ $(Q)cp $(srctree)/Documentation/rust/logo.svg $(objtree)/$(obj)/doc
+ $(Q)find $(objtree)/$(obj)/doc -name '*.html' -type f -print0 | xargs -0 sed -Ei \
+ -e 's:rust-logo\.png:logo.svg:g' \
+ -e 's:favicon\.svg:logo.svg:g' \
+ -e 's:<link rel="alternate icon" type="image/png" href="[./]*favicon-(16x16|32x32)\.png">::g'
+
+rustdoc-macros: private rustdoc_host = yes
+rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \
+ --extern proc_macro
+rustdoc-macros: $(src)/macros/lib.rs FORCE
+ $(call if_changed,rustdoc)
+
+rustdoc-core: private rustc_target_flags = $(core-cfgs)
+rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE
+ $(call if_changed,rustdoc)
+
+rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE
+ $(call if_changed,rustdoc)
+
+# We need to allow `rustdoc::broken_intra_doc_links` because some
+# `no_global_oom_handling` functions refer to non-`no_global_oom_handling`
+# functions. Ideally `rustdoc` would have a way to distinguish broken links
+# due to things that are "configured out" vs. entirely non-existing ones.
+rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \
+ -Arustdoc::broken_intra_doc_links
+rustdoc-alloc: $(src)/alloc/lib.rs rustdoc-core rustdoc-compiler_builtins FORCE
+ $(call if_changed,rustdoc)
+
+rustdoc-kernel: private rustc_target_flags = --extern alloc \
+ --extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so
+rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \
+ rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \
+ $(obj)/bindings_generated.rs $(obj)/bindings_helpers_generated.rs FORCE
+ $(call if_changed,rustdoc)
+
+quiet_cmd_rustc_test_library = RUSTC TL $<
+ cmd_rustc_test_library = \
+ OBJTREE=$(abspath $(objtree)) \
+ $(RUSTC) $(rust_common_flags) \
+ @$(objtree)/include/generated/rustc_cfg $(rustc_target_flags) \
+ --crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \
+ --out-dir $(objtree)/$(obj)/test --cfg testlib \
+ --sysroot $(objtree)/$(obj)/test/sysroot \
+ -L$(objtree)/$(obj)/test \
+ --crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $<
+
+rusttestlib-build_error: $(src)/build_error.rs rusttest-prepare FORCE
+ $(call if_changed,rustc_test_library)
+
+rusttestlib-macros: private rustc_target_flags = --extern proc_macro
+rusttestlib-macros: private rustc_test_library_proc = yes
+rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+ $(call if_changed,rustc_test_library)
+
+quiet_cmd_rustdoc_test = RUSTDOC T $<
+ cmd_rustdoc_test = \
+ OBJTREE=$(abspath $(objtree)) \
+ $(RUSTDOC) --test $(rust_common_flags) \
+ @$(objtree)/include/generated/rustc_cfg \
+ $(rustc_target_flags) $(rustdoc_test_target_flags) \
+ --sysroot $(objtree)/$(obj)/test/sysroot $(rustdoc_test_quiet) \
+ -L$(objtree)/$(obj)/test --output $(objtree)/$(obj)/doc \
+ --crate-name $(subst rusttest-,,$@) $<
+
+quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $<
+ cmd_rustdoc_test_kernel = \
+ rm -rf $(objtree)/$(obj)/test/doctests/kernel; \
+ mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \
+ OBJTREE=$(abspath $(objtree)) \
+ $(RUSTDOC) --test $(rust_flags) \
+ @$(objtree)/include/generated/rustc_cfg \
+ -L$(objtree)/$(obj) --extern alloc --extern kernel \
+ --extern build_error --extern macros \
+ --no-run --crate-name kernel -Zunstable-options \
+ --test-builder $(srctree)/scripts/rustdoc_test_builder.py \
+ $< $(rustdoc_test_kernel_quiet); \
+ $(srctree)/scripts/rustdoc_test_gen.py
+
+%/doctests_kernel_generated.rs %/doctests_kernel_generated_kunit.c: $(src)/kernel/lib.rs $(obj)/kernel.o FORCE
+ $(call if_changed,rustdoc_test_kernel)
+
+# We cannot use `-Zpanic-abort-tests` because some tests are dynamic,
+# so for the moment we skip `-Cpanic=abort`.
+quiet_cmd_rustc_test = RUSTC T $<
+ cmd_rustc_test = \
+ OBJTREE=$(abspath $(objtree)) \
+ $(RUSTC) --test $(rust_common_flags) \
+ @$(objtree)/include/generated/rustc_cfg \
+ $(rustc_target_flags) --out-dir $(objtree)/$(obj)/test \
+ --sysroot $(objtree)/$(obj)/test/sysroot \
+ -L$(objtree)/$(obj)/test \
+ --crate-name $(subst rusttest-,,$@) $<; \
+ $(objtree)/$(obj)/test/$(subst rusttest-,,$@) $(rust_test_quiet) \
+ $(rustc_test_run_flags)
+
+rusttest: rusttest-macros rusttest-kernel
+
+# This prepares a custom sysroot with our custom `alloc` instead of
+# the standard one.
+#
+# This requires several hacks:
+# - Unlike `core` and `alloc`, `std` depends on more than a dozen crates,
+# including third-party crates that need to be downloaded, plus custom
+# `build.rs` steps. Thus hardcoding things here is not maintainable.
+# - `cargo` knows how to build the standard library, but it is an unstable
+# feature so far (`-Zbuild-std`).
+# - `cargo` only considers the use case of building the standard library
+# to use it in a given package. Thus we need to create a dummy package
+# and pick the generated libraries from there.
+# - Since we only keep a subset of upstream `alloc` in-tree, we need
+# to recreate it on the fly by putting our sources on top.
+# - The usual ways of modifying the dependency graph in `cargo` do not seem
+# to apply for the `-Zbuild-std` steps, thus we have to mislead it
+# by modifying the sources in the sysroot.
+# - To avoid messing with the user's Rust installation, we create a clone
+# of the sysroot. However, `cargo` ignores `RUSTFLAGS` in the `-Zbuild-std`
+# steps, thus we use a wrapper binary passed via `RUSTC` to pass the flag.
+#
+# In the future, we hope to avoid the whole ordeal by either:
+# - Making the `test` crate not depend on `std` (either improving upstream
+# or having our own custom crate).
+# - Making the tests run in kernel space (requires the previous point).
+# - Making `std` and friends be more like a "normal" crate, so that
+# `-Zbuild-std` and related hacks are not needed.
+quiet_cmd_rustsysroot = RUSTSYSROOT
+ cmd_rustsysroot = \
+ rm -rf $(objtree)/$(obj)/test; \
+ mkdir -p $(objtree)/$(obj)/test; \
+ cp -a $(rustc_sysroot) $(objtree)/$(obj)/test/sysroot; \
+ cp -r $(srctree)/$(src)/alloc/* \
+ $(objtree)/$(obj)/test/sysroot/lib/rustlib/src/rust/library/alloc/src; \
+ echo '\#!/bin/sh' > $(objtree)/$(obj)/test/rustc_sysroot; \
+ echo "$(RUSTC) --sysroot=$(abspath $(objtree)/$(obj)/test/sysroot) \"\$$@\"" \
+ >> $(objtree)/$(obj)/test/rustc_sysroot; \
+ chmod u+x $(objtree)/$(obj)/test/rustc_sysroot; \
+ $(CARGO) -q new $(objtree)/$(obj)/test/dummy; \
+ RUSTC=$(objtree)/$(obj)/test/rustc_sysroot $(CARGO) $(cargo_quiet) \
+ test -Zbuild-std --target $(rustc_host_target) \
+ --manifest-path $(objtree)/$(obj)/test/dummy/Cargo.toml; \
+ rm $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib/*; \
+ cp $(objtree)/$(obj)/test/dummy/target/$(rustc_host_target)/debug/deps/* \
+ $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib
+
+rusttest-prepare: FORCE
+ $(call if_changed,rustsysroot)
+
+rusttest-macros: private rustc_target_flags = --extern proc_macro
+rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro
+rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+ $(call if_changed,rustc_test)
+ $(call if_changed,rustdoc_test)
+
+rusttest-kernel: private rustc_target_flags = --extern alloc \
+ --extern build_error --extern macros
+rusttest-kernel: private rustc_test_run_flags = --skip bindgen_test_layout_
+rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \
+ rusttestlib-build_error rusttestlib-macros FORCE
+ $(call if_changed,rustc_test)
+ $(call if_changed,rustc_test_library)
+
+filechk_rust_target = $(objtree)/scripts/generate_rust_target < $<
+
+$(obj)/target.json: $(objtree)/include/config/auto.conf FORCE
+ $(call filechk,rust_target)
+
+ifdef CONFIG_CC_IS_CLANG
+bindgen_c_flags = $(c_flags)
+else
+# bindgen relies on libclang to parse C. Ideally, bindgen would support a GCC
+# plugin backend and/or the Clang driver would be perfectly compatible with GCC.
+#
+# For the moment, here we are tweaking the flags on the fly. This is a hack,
+# and some kernel configurations may not work (e.g. `GCC_PLUGIN_RANDSTRUCT`
+# if we end up using one of those structs).
+bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
+ -mskip-rax-setup -mgeneral-regs-only -msign-return-address=% \
+ -mindirect-branch=thunk-extern -mindirect-branch-register \
+ -mrecord-mcount -mabi=lp64 -mstack-protector-guard% -mtraceback=no \
+ -mno-pointers-to-nested-functions -mno-string -mno-strict-align \
+ -mstrict-align \
+ -fconserve-stack -falign-jumps=% -falign-loops=% \
+ -femit-struct-debug-baseonly -fno-ipa-cp-clone -fno-ipa-sra \
+ -fno-partial-inlining -fplugin-arg-arm_ssp_per_task_plugin-% \
+ -fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \
+ -fzero-call-used-regs=% -fno-stack-clash-protection \
+ -fno-inline-functions-called-once \
+ --param=% --param asan-%
+
+# Derived from `scripts/Makefile.clang`.
+BINDGEN_TARGET_arm := arm-linux-gnueabi
+BINDGEN_TARGET_arm64 := aarch64-linux-gnu
+BINDGEN_TARGET_powerpc := powerpc64le-linux-gnu
+BINDGEN_TARGET_riscv := riscv64-linux-gnu
+BINDGEN_TARGET_x86 := x86_64-linux-gnu
+BINDGEN_TARGET := $(BINDGEN_TARGET_$(SRCARCH))
+
+# All warnings are inhibited since GCC builds are very experimental,
+# many GCC warnings are not supported by Clang, they may only appear in
+# some configurations, with new GCC versions, etc.
+bindgen_extra_c_flags = -w --target=$(BINDGEN_TARGET)
+
+bindgen_c_flags = $(filter-out $(bindgen_skip_c_flags), $(c_flags)) \
+ $(bindgen_extra_c_flags)
+endif
+
+ifdef CONFIG_LTO
+bindgen_c_flags_lto = $(filter-out $(CC_FLAGS_LTO), $(bindgen_c_flags))
+else
+bindgen_c_flags_lto = $(bindgen_c_flags)
+endif
+
+bindgen_c_flags_final = $(bindgen_c_flags_lto)
+
+quiet_cmd_bindgen = BINDGEN $@
+ cmd_bindgen = \
+ $(BINDGEN) $< $(bindgen_target_flags) \
+ --use-core --with-derive-default --ctypes-prefix c_types \
+ --no-debug '.*' \
+ --size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE \
+ $(bindgen_target_cflags) $(bindgen_target_extra)
+
+$(obj)/bindings_generated.rs: private bindgen_target_flags = \
+ $(shell grep -v '^\#\|^$$' $(srctree)/$(src)/bindgen_parameters)
+$(obj)/bindings_generated.rs: $(src)/kernel/bindings_helper.h \
+ $(src)/bindgen_parameters FORCE
+ $(call if_changed_dep,bindgen)
+
+# See `CFLAGS_REMOVE_helpers.o` above. In addition, Clang on C does not warn
+# with `-Wmissing-declarations` (unlike GCC), so it is not strictly needed here
+# given it is `libclang`; but for consistency, future Clang changes and/or
+# a potential future GCC backend for `bindgen`, we disable it too.
+$(obj)/bindings_helpers_generated.rs: private bindgen_target_flags = \
+ --blacklist-type '.*' --whitelist-var '' \
+ --whitelist-function 'rust_helper_.*'
+$(obj)/bindings_helpers_generated.rs: private bindgen_target_cflags = \
+ -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
+$(obj)/bindings_helpers_generated.rs: private bindgen_target_extra = ; \
+ sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/#[link_name="rust_helper_\1"]\n pub fn \1/g' $@
+$(obj)/bindings_helpers_generated.rs: $(src)/helpers.c FORCE
+ $(call if_changed_dep,bindgen)
+
+quiet_cmd_exports = EXPORTS $@
+ cmd_exports = \
+ $(NM) -p --defined-only $< \
+ | grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
+ | xargs -Isymbol \
+ echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
+
+$(obj)/exports_core_generated.h: $(obj)/core.o FORCE
+ $(call if_changed,exports)
+
+$(obj)/exports_alloc_generated.h: $(obj)/alloc.o FORCE
+ $(call if_changed,exports)
+
+$(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
+ $(call if_changed,exports)
+
+quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
+ cmd_rustc_procmacro = \
+ $(RUSTC_OR_CLIPPY) $(rust_common_flags) \
+ --emit=dep-info,link --extern proc_macro \
+ --crate-type proc-macro --out-dir $(objtree)/$(obj) \
+ --crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
+ mv $(objtree)/$(obj)/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \
+ sed -i '/^\#/d' $(depfile)
+
+# Procedural macros can only be used with the `rustc` that compiled it.
+# Therefore, to get `libmacros.so` automatically recompiled when the compiler
+# version changes, we add `core.o` as a dependency (even if it is not needed).
+$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE
+ $(call if_changed_dep,rustc_procmacro)
+
+quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@
+ cmd_rustc_library = \
+ OBJTREE=$(abspath $(objtree)) \
+ $(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \
+ $(filter-out $(skip_flags),$(rust_flags) $(rustc_target_flags)) \
+ --emit=dep-info,obj,metadata --crate-type rlib \
+ --out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \
+ --crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
+ mv $(objtree)/$(obj)/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \
+ sed -i '/^\#/d' $(depfile) \
+ $(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
+
+rust-analyzer:
+ $(Q)$(srctree)/scripts/generate_rust_analyzer.py $(srctree) $(objtree) \
+ $(RUST_LIB_SRC) > $(objtree)/rust-project.json
+
+$(obj)/core.o: private skip_clippy = 1
+$(obj)/core.o: private skip_flags = -Dunreachable_pub
+$(obj)/core.o: private rustc_target_flags = $(core-cfgs)
+$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs $(obj)/target.json FORCE
+ $(call if_changed_dep,rustc_library)
+
+$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'
+$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
+ $(call if_changed_dep,rustc_library)
+
+$(obj)/alloc.o: private skip_clippy = 1
+$(obj)/alloc.o: private skip_flags = -Dunreachable_pub
+$(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs)
+$(obj)/alloc.o: $(src)/alloc/lib.rs $(obj)/compiler_builtins.o FORCE
+ $(call if_changed_dep,rustc_library)
+
+$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE
+ $(call if_changed_dep,rustc_library)
+
+$(obj)/kernel.o: private rustc_target_flags = --extern alloc \
+ --extern build_error --extern macros
+$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \
+ $(obj)/libmacros.so $(obj)/bindings_generated.rs \
+ $(obj)/bindings_helpers_generated.rs FORCE
+ $(call if_changed_dep,rustc_library)
+
+endif # CONFIG_RUST
diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
new file mode 100644
index 000000000000..6c77865e8345
--- /dev/null
+++ b/rust/bindgen_parameters
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+
+--opaque-type xregs_state
+--opaque-type desc_struct
+--opaque-type arch_lbr_state
+--opaque-type local_apic
+
+# `try` is a reserved keyword since Rust 2018; solved in `bindgen` v0.59.2,
+# commit 2aed6b021680 ("context: Escape the try keyword properly").
+--opaque-type kunit_try_catch
+
+# If SMP is disabled, `arch_spinlock_t` is defined as a ZST which triggers a Rust
+# warning. We don't need to peek into it anyway.
+--opaque-type spinlock
+
+# `seccomp`'s comment gets understood as a doctest
+--no-doc-comments
diff --git a/scripts/.gitignore b/scripts/.gitignore
index eed308bef604..b7aec8eb1bd4 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
/asn1_compiler
/bin2c
+/generate_rust_target
/insert-sys-cert
/kallsyms
/module.lds
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index 0496efd6e117..83e850321eb6 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -36,12 +36,12 @@ ld-option = $(success,$(LD) -v $(1))
as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -)
# check if $(CC) and $(LD) exist
-$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
+$(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found)
$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
-# Get the compiler name, version, and error out if it is not supported.
+# Get the C compiler name, version, and error out if it is not supported.
cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC))
-$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not supported.)
+$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this C compiler is not supported.)
cc-name := $(shell,set -- $(cc-info) && echo $1)
cc-version := $(shell,set -- $(cc-info) && echo $2)
diff --git a/scripts/Makefile b/scripts/Makefile
index ce5aa9030b74..a278345e7820 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -10,6 +10,9 @@ hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT) += sorttable
hostprogs-always-$(CONFIG_ASN1) += asn1_compiler
hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT) += sign-file
hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert
+hostprogs-always-$(CONFIG_RUST) += generate_rust_target
+
+generate_rust_target-rust := y
HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
HOSTLDLIBS_sorttable = -lpthread
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 33c1ed581522..533631753b16 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -26,6 +26,7 @@ EXTRA_CPPFLAGS :=
EXTRA_LDFLAGS :=
asflags-y :=
ccflags-y :=
+rustflags-y :=
cppflags-y :=
ldflags-y :=
@@ -324,6 +325,65 @@ quiet_cmd_cc_lst_c = MKLST $@
$(obj)/%.lst: $(src)/%.c FORCE
$(call if_changed_dep,cc_lst_c)
+# Compile Rust sources (.rs)
+# ---------------------------------------------------------------------------
+
+rust_allowed_features := allocator_api,bench_black_box,concat_idents,generic_associated_types
+
+rust_common_cmd = \
+ RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
+ -Zallow-features=$(rust_allowed_features) \
+ -Zcrate-attr=no_std \
+ -Zcrate-attr='feature($(rust_allowed_features))' \
+ --extern alloc --extern kernel \
+ --crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
+ --crate-name $(basename $(notdir $@))
+
+rust_handle_depfile = \
+ mv $(obj)/$(basename $(notdir $@)).d $(depfile); \
+ sed -i '/^\#/d' $(depfile)
+
+# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
+# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
+# the compiler shows a warning if it is not 1. However, if we ever stop
+# requesting it explicitly and we start using some other `--emit` that does not
+# imply it (and for which codegen is performed), then we would be out of sync,
+# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
+# would not match each other.
+
+quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+ cmd_rustc_o_rs = \
+ $(rust_common_cmd) --emit=dep-info,obj $<; \
+ $(rust_handle_depfile)
+
+$(obj)/%.o: $(src)/%.rs FORCE
+ $(call if_changed_dep,rustc_o_rs)
+
+quiet_cmd_rustc_i_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+ cmd_rustc_i_rs = \
+ $(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
+ command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
+ $(rust_handle_depfile)
+
+$(obj)/%.i: $(src)/%.rs FORCE
+ $(call if_changed_dep,rustc_i_rs)
+
+quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+ cmd_rustc_s_rs = \
+ $(rust_common_cmd) --emit=dep-info,asm $<; \
+ $(rust_handle_depfile)
+
+$(obj)/%.s: $(src)/%.rs FORCE
+ $(call if_changed_dep,rustc_s_rs)
+
+quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+ cmd_rustc_ll_rs = \
+ $(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
+ $(rust_handle_depfile)
+
+$(obj)/%.ll: $(src)/%.rs FORCE
+ $(call if_changed_dep,rustc_ll_rs)
+
# Compile assembler sources (.S)
# ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
index 9f39b0130551..fe87389d52c0 100644
--- a/scripts/Makefile.debug
+++ b/scripts/Makefile.debug
@@ -1,4 +1,5 @@
DEBUG_CFLAGS :=
+DEBUG_RUSTFLAGS :=
ifdef CONFIG_DEBUG_INFO_SPLIT
DEBUG_CFLAGS += -gsplit-dwarf
@@ -10,6 +11,12 @@ ifndef CONFIG_AS_IS_LLVM
KBUILD_AFLAGS += -Wa,-gdwarf-2
endif
+ifdef CONFIG_DEBUG_INFO_REDUCED
+DEBUG_RUSTFLAGS += -Cdebuginfo=1
+else
+DEBUG_RUSTFLAGS += -Cdebuginfo=2
+endif
+
ifndef CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4
dwarf-version-$(CONFIG_DEBUG_INFO_DWARF5) := 5
@@ -31,3 +38,6 @@ endif
KBUILD_CFLAGS += $(DEBUG_CFLAGS)
export DEBUG_CFLAGS
+
+KBUILD_RUSTFLAGS += $(DEBUG_RUSTFLAGS)
+export DEBUG_RUSTFLAGS
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 278b4d6ac945..da133780b751 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -22,6 +22,8 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
# to preprocess a data file.
#
# Both C and C++ are supported, but preferred language is C for such utilities.
+# Rust is also supported, but it may only be used in scenarios where a Rust
+# toolchain is required to be available (e.g. when `CONFIG_RUST` is enabled).
#
# Sample syntax (see Documentation/kbuild/makefiles.rst for reference)
# hostprogs := bin2hex
@@ -37,15 +39,20 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
# qconf-objs := menu.o
# Will compile qconf as a C++ program, and menu as a C program.
# They are linked as C++ code to the executable qconf
+#
+# hostprogs := target
+# target-rust := y
+# Will compile `target` as a Rust program, using `target.rs` as the crate root.
+# The crate may consist of several source files.
# C code
# Executables compiled from a single .c file
host-csingle := $(foreach m,$(hostprogs), \
- $(if $($(m)-objs)$($(m)-cxxobjs),,$(m)))
+ $(if $($(m)-objs)$($(m)-cxxobjs)$($(m)-rust),,$(m)))
# C executables linked based on several .o files
host-cmulti := $(foreach m,$(hostprogs),\
- $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m))))
+ $(if $($(m)-cxxobjs)$($(m)-rust),,$(if $($(m)-objs),$(m))))
# Object (.o) files compiled from .c files
host-cobjs := $(sort $(foreach m,$(hostprogs),$($(m)-objs)))
@@ -58,11 +65,17 @@ host-cxxmulti := $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m)))
# C++ Object (.o) files compiled from .cc files
host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
+# Rust code
+# Executables compiled from a single Rust crate (which may consist of
+# one or more .rs files)
+host-rust := $(foreach m,$(hostprogs),$(if $($(m)-rust),$(m)))
+
host-csingle := $(addprefix $(obj)/,$(host-csingle))
host-cmulti := $(addprefix $(obj)/,$(host-cmulti))
host-cobjs := $(addprefix $(obj)/,$(host-cobjs))
host-cxxmulti := $(addprefix $(obj)/,$(host-cxxmulti))
host-cxxobjs := $(addprefix $(obj)/,$(host-cxxobjs))
+host-rust := $(addprefix $(obj)/,$(host-rust))
#####
# Handle options to gcc. Support building with separate output directory
@@ -71,6 +84,8 @@ _hostc_flags = $(KBUILD_HOSTCFLAGS) $(HOST_EXTRACFLAGS) \
$(HOSTCFLAGS_$(target-stem).o)
_hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
$(HOSTCXXFLAGS_$(target-stem).o)
+_hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
+ $(HOSTRUSTFLAGS_$(target-stem))
# $(objtree)/$(obj) for including generated headers from checkin source files
ifeq ($(KBUILD_EXTMOD),)
@@ -82,6 +97,7 @@ endif
hostc_flags = -Wp,-MMD,$(depfile) $(_hostc_flags)
hostcxx_flags = -Wp,-MMD,$(depfile) $(_hostcxx_flags)
+hostrust_flags = $(_hostrust_flags)
#####
# Compile programs on the host
@@ -128,5 +144,17 @@ quiet_cmd_host-cxxobjs = HOSTCXX $@
$(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
$(call if_changed_dep,host-cxxobjs)
+# Create executable from a single Rust crate (which may consist of
+# one or more `.rs` files)
+# host-rust -> Executable
+quiet_cmd_host-rust = HOSTRUSTC $@
+ cmd_host-rust = \
+ $(HOSTRUSTC) $(hostrust_flags) --emit=dep-info,link \
+ --out-dir=$(obj)/ $<; \
+ mv $(obj)/$(target-stem).d $(depfile); \
+ sed -i '/^\#/d' $(depfile)
+$(host-rust): $(obj)/%: $(src)/%.rs FORCE
+ $(call if_changed_dep,host-rust)
+
targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \
- $(host-cxxmulti) $(host-cxxobjs)
+ $(host-cxxmulti) $(host-cxxobjs) $(host-rust)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 9f69ecdd7977..f3e623f242df 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -8,6 +8,7 @@ ldflags-y += $(EXTRA_LDFLAGS)
# flags that take effect in current and sub directories
KBUILD_AFLAGS += $(subdir-asflags-y)
KBUILD_CFLAGS += $(subdir-ccflags-y)
+KBUILD_RUSTFLAGS += $(subdir-rustflags-y)
# Figure out what we need to build from the various variables
# ===========================================================================
@@ -128,6 +129,10 @@ _c_flags = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
$(filter-out $(ccflags-remove-y), \
$(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(ccflags-y)) \
$(CFLAGS_$(target-stem).o))
+_rust_flags = $(filter-out $(RUSTFLAGS_REMOVE_$(target-stem).o), \
+ $(filter-out $(rustflags-remove-y), \
+ $(KBUILD_RUSTFLAGS) $(rustflags-y)) \
+ $(RUSTFLAGS_$(target-stem).o))
_a_flags = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \
$(filter-out $(asflags-remove-y), \
$(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(asflags-y)) \
@@ -202,6 +207,11 @@ modkern_cflags = \
$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL) $(modfile_flags))
+modkern_rustflags = \
+ $(if $(part-of-module), \
+ $(KBUILD_RUSTFLAGS_MODULE) $(RUSTFLAGS_MODULE), \
+ $(KBUILD_RUSTFLAGS_KERNEL) $(RUSTFLAGS_KERNEL))
+
modkern_aflags = $(if $(part-of-module), \
$(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE), \
$(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL))
@@ -211,6 +221,8 @@ c_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(_c_flags) $(modkern_cflags) \
$(basename_flags) $(modname_flags)
+rust_flags = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg
+
a_flags = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(_a_flags) $(modkern_aflags)
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 7f39599e9fae..670d7997a38b 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -39,11 +39,13 @@ quiet_cmd_ld_ko_o = LD [M] $@
quiet_cmd_btf_ko = BTF [M] $@
cmd_btf_ko = \
- if [ -f vmlinux ]; then \
+ if [ ! -f vmlinux ]; then \
+ printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
+ elif [ -n "$(CONFIG_RUST)" ] && $(srctree)/scripts/is_rust_module.sh $@; then \
+ printf "Skipping BTF generation for %s because it's a Rust module\n" $@ 1>&2; \
+ else \
LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \
$(RESOLVE_BTFIDS) -b vmlinux $@; \
- else \
- printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
fi;
# Same as newer-prereqs, but allows to exclude specified extra dependencies
diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh
index f1952c522466..2401c86fcf53 100755
--- a/scripts/cc-version.sh
+++ b/scripts/cc-version.sh
@@ -1,13 +1,13 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
-# Print the compiler name and its version in a 5 or 6-digit form.
+# Print the C compiler name and its version in a 5 or 6-digit form.
# Also, perform the minimum version check.
set -e
-# Print the compiler name and some version components.
-get_compiler_info()
+# Print the C compiler name and some version components.
+get_c_compiler_info()
{
cat <<- EOF | "$@" -E -P -x c - 2>/dev/null
#if defined(__clang__)
@@ -32,7 +32,7 @@ get_canonical_version()
# $@ instead of $1 because multiple words might be given, e.g. CC="ccache gcc".
orig_args="$@"
-set -- $(get_compiler_info "$@")
+set -- $(get_c_compiler_info "$@")
name=$1
@@ -52,7 +52,7 @@ ICC)
min_version=$($min_tool_version icc)
;;
*)
- echo "$orig_args: unknown compiler" >&2
+ echo "$orig_args: unknown C compiler" >&2
exit 1
;;
esac
@@ -62,7 +62,7 @@ min_cversion=$(get_canonical_version $min_version)
if [ "$cversion" -lt "$min_cversion" ]; then
echo >&2 "***"
- echo >&2 "*** Compiler is too old."
+ echo >&2 "*** C compiler is too old."
echo >&2 "*** Your $name version: $version"
echo >&2 "*** Minimum $name version: $min_version"
echo >&2 "***"
diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
new file mode 100644
index 000000000000..e38842ad37a9
--- /dev/null
+++ b/scripts/generate_rust_target.rs
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The custom target specification file generator for `rustc`.
+//!
+//! To configure a target from scratch, a JSON-encoded file has to be passed
+//! to `rustc` (introduced in [RFC 131]). These options and the file itself are
+//! unstable. Eventually, `rustc` should provide a way to do this in a stable
+//! manner. For instance, via command-line arguments. Therefore, this file
+//! should avoid using keys which can be set via `-C` or `-Z` options.
+//!
+//! [RFC 131]: https://rust-lang.github.io/rfcs/0131-target-specification.html
+
+use std::{
+ collections::HashMap,
+ fmt::{Display, Formatter, Result},
+ io::BufRead,
+};
+
+enum Value {
+ Boolean(bool),
+ Number(i32),
+ String(String),
+ Object(Object),
+}
+
+type Object = Vec<(String, Value)>;
+
+/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
+/// enough for this purpose.
+impl Display for Value {
+ fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
+ match self {
+ Value::Boolean(boolean) => write!(formatter, "{}", boolean),
+ Value::Number(number) => write!(formatter, "{}", number),
+ Value::String(string) => write!(formatter, "\"{}\"", string),
+ Value::Object(object) => {
+ formatter.write_str("{")?;
+ if let [ref rest @ .., ref last] = object[..] {
+ for (key, value) in rest {
+ write!(formatter, "\"{}\": {},", key, value)?;
+ }
+ write!(formatter, "\"{}\": {}", last.0, last.1)?;
+ }
+ formatter.write_str("}")
+ }
+ }
+ }
+}
+
+struct TargetSpec(Object);
+
+impl TargetSpec {
+ fn new() -> TargetSpec {
+ TargetSpec(Vec::new())
+ }
+}
+
+trait Push<T> {
+ fn push(&mut self, key: &str, value: T);
+}
+
+impl Push<bool> for TargetSpec {
+ fn push(&mut self, key: &str, value: bool) {
+ self.0.push((key.to_string(), Value::Boolean(value)));
+ }
+}
+
+impl Push<i32> for TargetSpec {
+ fn push(&mut self, key: &str, value: i32) {
+ self.0.push((key.to_string(), Value::Number(value)));
+ }
+}
+
+impl Push<String> for TargetSpec {
+ fn push(&mut self, key: &str, value: String) {
+ self.0.push((key.to_string(), Value::String(value)));
+ }
+}
+
+impl Push<&str> for TargetSpec {
+ fn push(&mut self, key: &str, value: &str) {
+ self.push(key, value.to_string());
+ }
+}
+
+impl Push<Object> for TargetSpec {
+ fn push(&mut self, key: &str, value: Object) {
+ self.0.push((key.to_string(), Value::Object(value)));
+ }
+}
+
+impl Display for TargetSpec {
+ fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
+ // We add some newlines for clarity.
+ formatter.write_str("{\n")?;
+ if let [ref rest @ .., ref last] = self.0[..] {
+ for (key, value) in rest {
+ write!(formatter, " \"{}\": {},\n", key, value)?;
+ }
+ write!(formatter, " \"{}\": {}\n", last.0, last.1)?;
+ }
+ formatter.write_str("}")
+ }
+}
+
+struct KernelConfig(HashMap<String, String>);
+
+impl KernelConfig {
+ /// Parses `include/config/auto.conf` from `stdin`.
+ fn from_stdin() -> KernelConfig {
+ let mut result = HashMap::new();
+
+ let stdin = std::io::stdin();
+ let mut handle = stdin.lock();
+ let mut line = String::new();
+
+ loop {
+ line.clear();
+
+ if handle.read_line(&mut line).unwrap() == 0 {
+ break;
+ }
+
+ if line.starts_with('#') {
+ continue;
+ }
+
+ let (key, value) = line.split_once('=').expect("Missing `=` in line.");
+ result.insert(key.to_string(), value.trim_end_matches('\n').to_string());
+ }
+
+ KernelConfig(result)
+ }
+
+ /// Does the option exist in the configuration (any value)?
+ ///
+ /// The argument must be passed without the `CONFIG_` prefix.
+ /// This avoids repetition and it also avoids `fixdep` making us
+ /// depend on it.
+ fn has(&self, option: &str) -> bool {
+ let option = "CONFIG_".to_owned() + option;
+ self.0.contains_key(&option)
+ }
+}
+
+fn main() {
+ let cfg = KernelConfig::from_stdin();
+ let mut ts = TargetSpec::new();
+
+ // `llvm-target`s are taken from `scripts/Makefile.clang`.
+ if cfg.has("ARM") {
+ ts.push("arch", "arm");
+ ts.push(
+ "data-layout",
+ "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64",
+ );
+ ts.push("features", "+strict-align,+v6");
+ ts.push("llvm-target", "arm-linux-gnueabi");
+ ts.push("max-atomic-width", 64);
+ ts.push("target-mcount", "\\u0001__gnu_mcount_nc");
+ ts.push("target-pointer-width", "32");
+ } else if cfg.has("ARM64") {
+ ts.push("arch", "aarch64");
+ ts.push(
+ "data-layout",
+ "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128",
+ );
+ ts.push("disable-redzone", true);
+ ts.push("features", "+strict-align,-neon,-fp-armv8");
+ ts.push("llvm-target", "aarch64-linux-gnu");
+ ts.push("max-atomic-width", 128);
+ ts.push("target-pointer-width", "64");
+ } else if cfg.has("PPC") {
+ ts.push("arch", "powerpc64");
+ ts.push("code-model", "large");
+ ts.push("data-layout", "e-m:e-i64:64-n32:64");
+ ts.push("features", "-altivec,-vsx,-hard-float");
+ ts.push("llvm-target", "powerpc64le-linux-gnu");
+ ts.push("max-atomic-width", 64);
+ ts.push("target-mcount", "_mcount");
+ ts.push("target-pointer-width", "64");
+ } else if cfg.has("RISCV") {
+ if cfg.has("64BIT") {
+ ts.push("arch", "riscv64");
+ ts.push("data-layout", "e-m:e-p:64:64-i64:64-i128:128-n64-S128");
+ ts.push("llvm-target", "riscv64-linux-gnu");
+ ts.push("target-pointer-width", "64");
+ } else {
+ ts.push("arch", "riscv32");
+ ts.push("data-layout", "e-m:e-p:32:32-i64:64-n32-S128");
+ ts.push("llvm-target", "riscv32-linux-gnu");
+ ts.push("target-pointer-width", "32");
+ }
+ ts.push("code-model", "medium");
+ ts.push("disable-redzone", true);
+ let mut features = "+m,+a".to_string();
+ if cfg.has("RISCV_ISA_C") {
+ features += ",+c";
+ }
+ ts.push("features", features);
+ } else if cfg.has("X86") {
+ ts.push("arch", "x86_64");
+ ts.push(
+ "data-layout",
+ "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128",
+ );
+ ts.push("llvm-target", "x86_64-linux-gnu");
+ ts.push("target-pointer-width", "64");
+ } else {
+ panic!("Unsupported architecture");
+ }
+
+ ts.push("emit-debug-gdb-scripts", false);
+ ts.push("frame-pointer", "may-omit");
+ ts.push(
+ "stack-probes",
+ vec![("kind".to_string(), Value::String("none".to_string()))],
+ );
+
+ // Everything else is LE, whether `CPU_LITTLE_ENDIAN` is declared or not
+ // (e.g. x86). It is also `rustc`'s default.
+ if cfg.has("CPU_BIG_ENDIAN") {
+ ts.push("target-endian", "big");
+ }
+
+ println!("{}", ts);
+}
diff --git a/scripts/is_rust_module.sh b/scripts/is_rust_module.sh
new file mode 100755
index 000000000000..277a64d07f22
--- /dev/null
+++ b/scripts/is_rust_module.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# is_rust_module.sh module.ko
+#
+# Returns `0` if `module.ko` is a Rust module, `1` otherwise.
+
+set -e
+
+# Using the `16_` prefix ensures other symbols with the same substring
+# are not picked up (even if it would be unlikely). The last part is
+# used just in case LLVM decides to use the `.` suffix.
+${NM} "$*" | grep -qE '^[0-9a-fA-F]+ r _R[^[:space:]]+16___IS_RUST_MODULE[^[:space:]]*$'
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index c4340c90e172..b7c9f1dd5e42 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -216,6 +216,13 @@ static const char *conf_get_autoheader_name(void)
return name ? name : "include/generated/autoconf.h";
}
+static const char *conf_get_rustccfg_name(void)
+{
+ char *name = getenv("KCONFIG_RUSTCCFG");
+
+ return name ? name : "include/generated/rustc_cfg";
+}
+
static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
{
char *p2;
@@ -605,6 +612,9 @@ static const struct comment_style comment_style_c = {
static void conf_write_heading(FILE *fp, const struct comment_style *cs)
{
+ if (!cs)
+ return;
+
fprintf(fp, "%s\n", cs->prefix);
fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
@@ -745,6 +755,65 @@ static void print_symbol_for_c(FILE *fp, struct symbol *sym)
free(escaped);
}
+static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
+{
+ const char *val;
+ const char *val_prefix = "";
+ char *val_prefixed = NULL;
+ size_t val_prefixed_len;
+ char *escaped = NULL;
+
+ if (sym->type == S_UNKNOWN)
+ return;
+
+ val = sym_get_string_value(sym);
+
+ switch (sym->type) {
+ case S_BOOLEAN:
+ case S_TRISTATE:
+ /*
+ * We do not care about disabled ones, i.e. no need for
+ * what otherwise are "comments" in other printers.
+ */
+ if (*val == 'n')
+ return;
+
+ /*
+ * To have similar functionality to the C macro `IS_ENABLED()`
+ * we provide an empty `--cfg CONFIG_X` here in both `y`
+ * and `m` cases.
+ *
+ * Then, the common `fprintf()` below will also give us
+ * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
+ * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
+ */
+ fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
+ break;
+ case S_HEX:
+ if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
+ val_prefix = "0x";
+ break;
+ default:
+ break;
+ }
+
+ if (strlen(val_prefix) > 0) {
+ val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
+ val_prefixed = xmalloc(val_prefixed_len);
+ snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
+ val = val_prefixed;
+ }
+
+ /* All values get escaped: the `--cfg` option only takes strings */
+ escaped = escape_string_value(val);
+ val = escaped;
+
+ fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
+
+ free(escaped);
+ free(val_prefixed);
+}
+
/*
* Write out a minimal config.
* All values that has default values are skipped as this is redundant.
@@ -1132,6 +1201,12 @@ int conf_write_autoconf(int overwrite)
if (ret)
return ret;
+ ret = __conf_write_autoconf(conf_get_rustccfg_name(),
+ print_symbol_for_rustccfg,
+ NULL);
+ if (ret)
+ return ret;
+
/*
* Create include/config/auto.conf. This must be the last step because
* Kbuild has a dependency on auto.conf and this marks the successful
diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
index 7c20252a90c6..53fe64856015 100755
--- a/scripts/min-tool-version.sh
+++ b/scripts/min-tool-version.sh
@@ -31,6 +31,12 @@ llvm)
echo 11.0.0
fi
;;
+rustc)
+ echo 1.60.0
+ ;;
+bindgen)
+ echo 0.56.0
+ ;;
*)
echo "$1: unknown tool" >&2
exit 1
diff --git a/scripts/rust-is-available-bindgen-libclang.h b/scripts/rust-is-available-bindgen-libclang.h
new file mode 100644
index 000000000000..0ef6db10d674
--- /dev/null
+++ b/scripts/rust-is-available-bindgen-libclang.h
@@ -0,0 +1,2 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#pragma message("clang version " __clang_version__)
diff --git a/scripts/rust-is-available.sh b/scripts/rust-is-available.sh
new file mode 100755
index 000000000000..6bd395167d0f
--- /dev/null
+++ b/scripts/rust-is-available.sh
@@ -0,0 +1,158 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Tests whether a suitable Rust toolchain is available.
+#
+# Pass `-v` for human output and more checks (as warnings).
+
+set -e
+
+min_tool_version=$(dirname $0)/min-tool-version.sh
+
+# Convert the version string x.y.z to a canonical up-to-7-digits form.
+#
+# Note that this function uses one more digit (compared to other
+# instances in other version scripts) to give a bit more space to
+# `rustc` since it will reach 1.100.0 in late 2026.
+get_canonical_version()
+{
+ IFS=.
+ set -- $1
+ echo $((100000 * $1 + 100 * $2 + $3))
+}
+
+# Check that the Rust compiler exists.
+if ! command -v "$RUSTC" >/dev/null; then
+ if [ "$1" = -v ]; then
+ echo >&2 "***"
+ echo >&2 "*** Rust compiler '$RUSTC' could not be found."
+ echo >&2 "***"
+ fi
+ exit 1
+fi
+
+# Check that the Rust bindings generator exists.
+if ! command -v "$BINDGEN" >/dev/null; then
+ if [ "$1" = -v ]; then
+ echo >&2 "***"
+ echo >&2 "*** Rust bindings generator '$BINDGEN' could not be found."
+ echo >&2 "***"
+ fi
+ exit 1
+fi
+
+# Check that the Rust compiler version is suitable.
+#
+# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
+rust_compiler_version=$( \
+ LC_ALL=C "$RUSTC" --version 2>/dev/null \
+ | head -n 1 \
+ | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+rust_compiler_min_version=$($min_tool_version rustc)
+rust_compiler_cversion=$(get_canonical_version $rust_compiler_version)
+rust_compiler_min_cversion=$(get_canonical_version $rust_compiler_min_version)
+if [ "$rust_compiler_cversion" -lt "$rust_compiler_min_cversion" ]; then
+ if [ "$1" = -v ]; then
+ echo >&2 "***"
+ echo >&2 "*** Rust compiler '$RUSTC' is too old."
+ echo >&2 "*** Your version: $rust_compiler_version"
+ echo >&2 "*** Minimum version: $rust_compiler_min_version"
+ echo >&2 "***"
+ fi
+ exit 1
+fi
+if [ "$1" = -v ] && [ "$rust_compiler_cversion" -gt "$rust_compiler_min_cversion" ]; then
+ echo >&2 "***"
+ echo >&2 "*** Rust compiler '$RUSTC' is too new. This may or may not work."
+ echo >&2 "*** Your version: $rust_compiler_version"
+ echo >&2 "*** Expected version: $rust_compiler_min_version"
+ echo >&2 "***"
+fi
+
+# Check that the Rust bindings generator is suitable.
+#
+# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
+rust_bindings_generator_version=$( \
+ LC_ALL=C "$BINDGEN" --version 2>/dev/null \
+ | head -n 1 \
+ | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+rust_bindings_generator_min_version=$($min_tool_version bindgen)
+rust_bindings_generator_cversion=$(get_canonical_version $rust_bindings_generator_version)
+rust_bindings_generator_min_cversion=$(get_canonical_version $rust_bindings_generator_min_version)
+if [ "$rust_bindings_generator_cversion" -lt "$rust_bindings_generator_min_cversion" ]; then
+ if [ "$1" = -v ]; then
+ echo >&2 "***"
+ echo >&2 "*** Rust bindings generator '$BINDGEN' is too old."
+ echo >&2 "*** Your version: $rust_bindings_generator_version"
+ echo >&2 "*** Minimum version: $rust_bindings_generator_min_version"
+ echo >&2 "***"
+ fi
+ exit 1
+fi
+if [ "$1" = -v ] && [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cversion" ]; then
+ echo >&2 "***"
+ echo >&2 "*** Rust bindings generator '$BINDGEN' is too new. This may or may not work."
+ echo >&2 "*** Your version: $rust_bindings_generator_version"
+ echo >&2 "*** Expected version: $rust_bindings_generator_min_version"
+ echo >&2 "***"
+fi
+
+# Check that the `libclang` used by the Rust bindings generator is suitable.
+bindgen_libclang_version=$( \
+ LC_ALL=C "$BINDGEN" $(dirname $0)/rust-is-available-bindgen-libclang.h 2>&1 >/dev/null \
+ | grep -F 'clang version ' \
+ | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+bindgen_libclang_min_version=$($min_tool_version llvm)
+bindgen_libclang_cversion=$(get_canonical_version $bindgen_libclang_version)
+bindgen_libclang_min_cversion=$(get_canonical_version $bindgen_libclang_min_version)
+if [ "$bindgen_libclang_cversion" -lt "$bindgen_libclang_min_cversion" ]; then
+ if [ "$1" = -v ]; then
+ echo >&2 "***"
+ echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') is too old."
+ echo >&2 "*** Your version: $bindgen_libclang_version"
+ echo >&2 "*** Minimum version: $bindgen_libclang_min_version"
+ echo >&2 "***"
+ fi
+ exit 1
+fi
+
+# If the C compiler is Clang, then we can also check whether its version
+# matches the `libclang` version used by the Rust bindings generator.
+#
+# In the future, we might be able to perform a full version check, see
+# https://github.com/rust-lang/rust-bindgen/issues/2138.
+if [ "$1" = -v ]; then
+ cc_name=$($(dirname $0)/cc-version.sh "$CC" | cut -f1 -d' ')
+ if [ "$cc_name" = Clang ]; then
+ clang_version=$( \
+ LC_ALL=C "$CC" --version 2>/dev/null \
+ | sed -nE '1s:.*version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
+ )
+ if [ "$clang_version" != "$bindgen_libclang_version" ]; then
+ echo >&2 "***"
+ echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') version does not match Clang's. This may be a problem."
+ echo >&2 "*** libclang version: $bindgen_libclang_version"
+ echo >&2 "*** Clang version: $clang_version"
+ echo >&2 "***"
+ fi
+ fi
+fi
+
+# Check that the source code for the `core` standard library exists.
+#
+# `$KRUSTFLAGS` is passed in case the user added `--sysroot`.
+rustc_sysroot=$("$RUSTC" $KRUSTFLAGS --print sysroot)
+rustc_src=${RUST_LIB_SRC:-"$rustc_sysroot/lib/rustlib/src/rust/library"}
+rustc_src_core="$rustc_src/core/src/lib.rs"
+if [ ! -e "$rustc_src_core" ]; then
+ if [ "$1" = -v ]; then
+ echo >&2 "***"
+ echo >&2 "*** Source code for the 'core' standard library could not be found"
+ echo >&2 "*** at '$rustc_src_core'."
+ echo >&2 "***"
+ fi
+ exit 1
+fi
--
2.35.3
From: Gary Guo <[email protected]>
This patch adds a format specifier `%pA` to `vsprintf` which formats
a pointer as `core::fmt::Arguments`. Doing so allows us to directly
format to the internal buffer of `printf`, so we do not have to use
a temporary buffer on the stack to pre-assemble the message on
the Rust side.
This specifier is intended only to be used from Rust and not for C, so
`checkpatch.pl` is intentionally unchanged to catch any misuse.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
lib/vsprintf.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 40d26a07a133..00f71f91d991 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2270,6 +2270,9 @@ int __init no_hash_pointers_enable(char *str)
}
early_param("no_hash_pointers", no_hash_pointers_enable);
+/* Used for Rust formatting ('%pA'). */
+char *rust_fmt_argument(char *buf, char *end, void *ptr);
+
/*
* Show a '%p' thing. A kernel extension is that the '%p' is followed
* by an extra set of alphanumeric characters that are extended format
@@ -2396,6 +2399,10 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
*
* Note: The default behaviour (unadorned %p) is to hash the address,
* rendering it useful as a unique identifier.
+ *
+ * There is also a '%pA' format specifier, but it is only intended to be used
+ * from Rust code to format core::fmt::Arguments. Do *not* use it from C.
+ * See rust/kernel/print.rs for details.
*/
static noinline_for_stack
char *pointer(const char *fmt, char *buf, char *end, void *ptr,
@@ -2468,6 +2475,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
return device_node_string(buf, end, ptr, spec, fmt + 1);
case 'f':
return fwnode_string(buf, end, ptr, spec, fmt + 1);
+ case 'A':
+ if (!IS_ENABLED(CONFIG_RUST)) {
+ WARN_ONCE(1, "Please remove %%pA from non-Rust code\n");
+ return error_string(buf, end, "(%pA?)", spec);
+ }
+ return rust_fmt_argument(buf, end, ptr);
case 'x':
return pointer_string(buf, end, ptr, spec);
case 'e':
--
2.35.3
From: Wedson Almeida Filho <[email protected]>
A port to Rust of the Android Binder IPC mechanism.
This module is a work in progress and will be sent for review later
on, as well as separately from the Rust support.
However, it is included to show how an actual working module
written in Rust may look like.
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Finn Behrens <[email protected]>
Signed-off-by: Finn Behrens <[email protected]>
Co-developed-by: Sven Van Asbroeck <[email protected]>
Signed-off-by: Sven Van Asbroeck <[email protected]>
Co-developed-by: Gary Guo <[email protected]>
Signed-off-by: Gary Guo <[email protected]>
Co-developed-by: Wayne Campbell <[email protected]>
Signed-off-by: Wayne Campbell <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Co-developed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
drivers/android/Kconfig | 6 +
drivers/android/Makefile | 2 +
drivers/android/allocation.rs | 266 ++++++++
drivers/android/context.rs | 80 +++
drivers/android/defs.rs | 99 +++
drivers/android/node.rs | 476 ++++++++++++++
drivers/android/process.rs | 960 ++++++++++++++++++++++++++++
drivers/android/range_alloc.rs | 189 ++++++
drivers/android/rust_binder.rs | 111 ++++
drivers/android/thread.rs | 870 +++++++++++++++++++++++++
drivers/android/transaction.rs | 326 ++++++++++
include/uapi/linux/android/binder.h | 28 +-
12 files changed, 3400 insertions(+), 13 deletions(-)
create mode 100644 drivers/android/allocation.rs
create mode 100644 drivers/android/context.rs
create mode 100644 drivers/android/defs.rs
create mode 100644 drivers/android/node.rs
create mode 100644 drivers/android/process.rs
create mode 100644 drivers/android/range_alloc.rs
create mode 100644 drivers/android/rust_binder.rs
create mode 100644 drivers/android/thread.rs
create mode 100644 drivers/android/transaction.rs
diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig
index 53b22e26266c..bc10eebd3ad3 100644
--- a/drivers/android/Kconfig
+++ b/drivers/android/Kconfig
@@ -20,6 +20,12 @@ config ANDROID_BINDER_IPC
Android process, using Binder to identify, invoke and pass arguments
between said processes.
+config ANDROID_BINDER_IPC_RUST
+ bool "Android Binder IPC Driver in Rust"
+ depends on MMU && RUST
+ help
+ Implementation of the Binder IPC in Rust.
+
config ANDROID_BINDERFS
bool "Android Binderfs filesystem"
depends on ANDROID_BINDER_IPC
diff --git a/drivers/android/Makefile b/drivers/android/Makefile
index c9d3d0c99c25..c428f2ce2f05 100644
--- a/drivers/android/Makefile
+++ b/drivers/android/Makefile
@@ -4,3 +4,5 @@ ccflags-y += -I$(src) # needed for trace events
obj-$(CONFIG_ANDROID_BINDERFS) += binderfs.o
obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o binder_alloc.o
obj-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o
+
+obj-$(CONFIG_ANDROID_BINDER_IPC_RUST) += rust_binder.o
diff --git a/drivers/android/allocation.rs b/drivers/android/allocation.rs
new file mode 100644
index 000000000000..3ed7b649eeb7
--- /dev/null
+++ b/drivers/android/allocation.rs
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::mem::{replace, size_of, MaybeUninit};
+use kernel::{
+ bindings, linked_list::List, pages::Pages, prelude::*, sync::Ref, user_ptr::UserSlicePtrReader,
+};
+
+use crate::{
+ defs::*,
+ node::NodeRef,
+ process::{AllocationInfo, Process},
+ thread::{BinderError, BinderResult},
+ transaction::FileInfo,
+};
+
+pub(crate) struct Allocation<'a> {
+ pub(crate) offset: usize,
+ size: usize,
+ pub(crate) ptr: usize,
+ pages: Ref<[Pages<0>]>,
+ pub(crate) process: &'a Process,
+ allocation_info: Option<AllocationInfo>,
+ free_on_drop: bool,
+ file_list: List<Box<FileInfo>>,
+}
+
+impl<'a> Allocation<'a> {
+ pub(crate) fn new(
+ process: &'a Process,
+ offset: usize,
+ size: usize,
+ ptr: usize,
+ pages: Ref<[Pages<0>]>,
+ ) -> Self {
+ Self {
+ process,
+ offset,
+ size,
+ ptr,
+ pages,
+ allocation_info: None,
+ free_on_drop: true,
+ file_list: List::new(),
+ }
+ }
+
+ pub(crate) fn take_file_list(&mut self) -> List<Box<FileInfo>> {
+ replace(&mut self.file_list, List::new())
+ }
+
+ pub(crate) fn add_file_info(&mut self, file: Box<FileInfo>) {
+ self.file_list.push_back(file);
+ }
+
+ fn iterate<T>(&self, mut offset: usize, mut size: usize, mut cb: T) -> Result
+ where
+ T: FnMut(&Pages<0>, usize, usize) -> Result,
+ {
+ // Check that the request is within the buffer.
+ if offset.checked_add(size).ok_or(EINVAL)? > self.size {
+ return Err(EINVAL);
+ }
+ offset += self.offset;
+ let mut page_index = offset >> bindings::PAGE_SHIFT;
+ offset &= (1 << bindings::PAGE_SHIFT) - 1;
+ while size > 0 {
+ let available = core::cmp::min(size, (1 << bindings::PAGE_SHIFT) as usize - offset);
+ cb(&self.pages[page_index], offset, available)?;
+ size -= available;
+ page_index += 1;
+ offset = 0;
+ }
+ Ok(())
+ }
+
+ pub(crate) fn copy_into(
+ &self,
+ reader: &mut UserSlicePtrReader,
+ offset: usize,
+ size: usize,
+ ) -> Result {
+ self.iterate(offset, size, |page, offset, to_copy| {
+ page.copy_into_page(reader, offset, to_copy)
+ })
+ }
+
+ pub(crate) fn read<T>(&self, offset: usize) -> Result<T> {
+ let mut out = MaybeUninit::<T>::uninit();
+ let mut out_offset = 0;
+ self.iterate(offset, size_of::<T>(), |page, offset, to_copy| {
+ // SAFETY: Data buffer is allocated on the stack.
+ unsafe {
+ page.read(
+ (out.as_mut_ptr() as *mut u8).add(out_offset),
+ offset,
+ to_copy,
+ )
+ }?;
+ out_offset += to_copy;
+ Ok(())
+ })?;
+ // SAFETY: We just initialised the data.
+ Ok(unsafe { out.assume_init() })
+ }
+
+ pub(crate) fn write<T>(&self, offset: usize, obj: &T) -> Result {
+ let mut obj_offset = 0;
+ self.iterate(offset, size_of::<T>(), |page, offset, to_copy| {
+ // SAFETY: The sum of `offset` and `to_copy` is bounded by the size of T.
+ let obj_ptr = unsafe { (obj as *const T as *const u8).add(obj_offset) };
+ // SAFETY: We have a reference to the object, so the pointer is valid.
+ unsafe { page.write(obj_ptr, offset, to_copy) }?;
+ obj_offset += to_copy;
+ Ok(())
+ })
+ }
+
+ pub(crate) fn keep_alive(mut self) {
+ self.process
+ .buffer_make_freeable(self.offset, self.allocation_info.take());
+ self.free_on_drop = false;
+ }
+
+ pub(crate) fn set_info(&mut self, info: AllocationInfo) {
+ self.allocation_info = Some(info);
+ }
+}
+
+impl Drop for Allocation<'_> {
+ fn drop(&mut self) {
+ if !self.free_on_drop {
+ return;
+ }
+
+ if let Some(info) = &self.allocation_info {
+ let offsets = info.offsets.clone();
+ let view = AllocationView::new(self, offsets.start);
+ for i in offsets.step_by(size_of::<usize>()) {
+ if view.cleanup_object(i).is_err() {
+ pr_warn!("Error cleaning up object at offset {}\n", i)
+ }
+ }
+ }
+
+ self.process.buffer_raw_free(self.ptr);
+ }
+}
+
+pub(crate) struct AllocationView<'a, 'b> {
+ pub(crate) alloc: &'a mut Allocation<'b>,
+ limit: usize,
+}
+
+impl<'a, 'b> AllocationView<'a, 'b> {
+ pub(crate) fn new(alloc: &'a mut Allocation<'b>, limit: usize) -> Self {
+ AllocationView { alloc, limit }
+ }
+
+ pub(crate) fn read<T>(&self, offset: usize) -> Result<T> {
+ if offset.checked_add(size_of::<T>()).ok_or(EINVAL)? > self.limit {
+ return Err(EINVAL);
+ }
+ self.alloc.read(offset)
+ }
+
+ pub(crate) fn write<T>(&self, offset: usize, obj: &T) -> Result {
+ if offset.checked_add(size_of::<T>()).ok_or(EINVAL)? > self.limit {
+ return Err(EINVAL);
+ }
+ self.alloc.write(offset, obj)
+ }
+
+ pub(crate) fn transfer_binder_object<T>(
+ &self,
+ offset: usize,
+ strong: bool,
+ get_node: T,
+ ) -> BinderResult
+ where
+ T: FnOnce(&bindings::flat_binder_object) -> BinderResult<NodeRef>,
+ {
+ // TODO: Do we want this function to take a &mut self?
+ let obj = self.read::<bindings::flat_binder_object>(offset)?;
+ let node_ref = get_node(&obj)?;
+
+ if core::ptr::eq(&*node_ref.node.owner, self.alloc.process) {
+ // The receiving process is the owner of the node, so send it a binder object (instead
+ // of a handle).
+ let (ptr, cookie) = node_ref.node.get_id();
+ let newobj = bindings::flat_binder_object {
+ hdr: bindings::binder_object_header {
+ type_: if strong {
+ BINDER_TYPE_BINDER
+ } else {
+ BINDER_TYPE_WEAK_BINDER
+ },
+ },
+ flags: obj.flags,
+ __bindgen_anon_1: bindings::flat_binder_object__bindgen_ty_1 { binder: ptr as _ },
+ cookie: cookie as _,
+ };
+ self.write(offset, &newobj)?;
+
+ // Increment the user ref count on the node. It will be decremented as part of the
+ // destruction of the buffer, when we see a binder or weak-binder object.
+ node_ref.node.update_refcount(true, strong);
+ } else {
+ // The receiving process is different from the owner, so we need to insert a handle to
+ // the binder object.
+ let handle = self
+ .alloc
+ .process
+ .insert_or_update_handle(node_ref, false)?;
+
+ let newobj = bindings::flat_binder_object {
+ hdr: bindings::binder_object_header {
+ type_: if strong {
+ BINDER_TYPE_HANDLE
+ } else {
+ BINDER_TYPE_WEAK_HANDLE
+ },
+ },
+ flags: obj.flags,
+ // TODO: To avoid padding, we write to `binder` instead of `handle` here. We need a
+ // better solution though.
+ __bindgen_anon_1: bindings::flat_binder_object__bindgen_ty_1 {
+ binder: handle as _,
+ },
+ ..bindings::flat_binder_object::default()
+ };
+ if self.write(offset, &newobj).is_err() {
+ // Decrement ref count on the handle we just created.
+ let _ = self.alloc.process.update_ref(handle, false, strong);
+ return Err(BinderError::new_failed());
+ }
+ }
+ Ok(())
+ }
+
+ fn cleanup_object(&self, index_offset: usize) -> Result {
+ let offset = self.alloc.read(index_offset)?;
+ let header = self.read::<bindings::binder_object_header>(offset)?;
+ // TODO: Handle other types.
+ match header.type_ {
+ BINDER_TYPE_WEAK_BINDER | BINDER_TYPE_BINDER => {
+ let obj = self.read::<bindings::flat_binder_object>(offset)?;
+ let strong = header.type_ == BINDER_TYPE_BINDER;
+ // SAFETY: The type is `BINDER_TYPE_{WEAK_}BINDER`, so the `binder` field is
+ // populated.
+ let ptr = unsafe { obj.__bindgen_anon_1.binder } as usize;
+ let cookie = obj.cookie as usize;
+ self.alloc.process.update_node(ptr, cookie, strong, false);
+ Ok(())
+ }
+ BINDER_TYPE_WEAK_HANDLE | BINDER_TYPE_HANDLE => {
+ let obj = self.read::<bindings::flat_binder_object>(offset)?;
+ let strong = header.type_ == BINDER_TYPE_HANDLE;
+ // SAFETY: The type is `BINDER_TYPE_{WEAK_}HANDLE`, so the `handle` field is
+ // populated.
+ let handle = unsafe { obj.__bindgen_anon_1.handle } as _;
+ self.alloc.process.update_ref(handle, false, strong)
+ }
+ _ => Ok(()),
+ }
+ }
+}
diff --git a/drivers/android/context.rs b/drivers/android/context.rs
new file mode 100644
index 000000000000..2bb448df6641
--- /dev/null
+++ b/drivers/android/context.rs
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::{
+ bindings,
+ prelude::*,
+ security,
+ sync::{Mutex, Ref, UniqueRef},
+};
+
+use crate::{
+ node::NodeRef,
+ thread::{BinderError, BinderResult},
+};
+
+struct Manager {
+ node: Option<NodeRef>,
+ uid: Option<bindings::kuid_t>,
+}
+
+pub(crate) struct Context {
+ manager: Mutex<Manager>,
+}
+
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl Send for Context {}
+unsafe impl Sync for Context {}
+
+impl Context {
+ pub(crate) fn new() -> Result<Ref<Self>> {
+ let mut ctx = Pin::from(UniqueRef::try_new(Self {
+ // SAFETY: Init is called below.
+ manager: unsafe {
+ Mutex::new(Manager {
+ node: None,
+ uid: None,
+ })
+ },
+ })?);
+
+ // SAFETY: `manager` is also pinned when `ctx` is.
+ let manager = unsafe { ctx.as_mut().map_unchecked_mut(|c| &mut c.manager) };
+ kernel::mutex_init!(manager, "Context::manager");
+
+ Ok(ctx.into())
+ }
+
+ pub(crate) fn set_manager_node(&self, node_ref: NodeRef) -> Result {
+ let mut manager = self.manager.lock();
+ if manager.node.is_some() {
+ return Err(EBUSY);
+ }
+ security::binder_set_context_mgr(&node_ref.node.owner.cred)?;
+
+ // TODO: Get the actual caller id.
+ let caller_uid = bindings::kuid_t::default();
+ if let Some(ref uid) = manager.uid {
+ if uid.val != caller_uid.val {
+ return Err(EPERM);
+ }
+ }
+
+ manager.node = Some(node_ref);
+ manager.uid = Some(caller_uid);
+ Ok(())
+ }
+
+ pub(crate) fn unset_manager_node(&self) {
+ let node_ref = self.manager.lock().node.take();
+ drop(node_ref);
+ }
+
+ pub(crate) fn get_manager_node(&self, strong: bool) -> BinderResult<NodeRef> {
+ self.manager
+ .lock()
+ .node
+ .as_ref()
+ .ok_or_else(BinderError::new_dead)?
+ .clone(strong)
+ }
+}
diff --git a/drivers/android/defs.rs b/drivers/android/defs.rs
new file mode 100644
index 000000000000..ec2dde9b3dd8
--- /dev/null
+++ b/drivers/android/defs.rs
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::ops::{Deref, DerefMut};
+use kernel::{
+ bindings,
+ bindings::*,
+ io_buffer::{ReadableFromBytes, WritableToBytes},
+};
+
+macro_rules! pub_no_prefix {
+ ($prefix:ident, $($newname:ident),+) => {
+ $(pub(crate) const $newname: u32 = concat_idents!($prefix, $newname);)+
+ };
+}
+
+pub_no_prefix!(
+ binder_driver_return_protocol_,
+ BR_OK,
+ BR_ERROR,
+ BR_TRANSACTION,
+ BR_REPLY,
+ BR_DEAD_REPLY,
+ BR_TRANSACTION_COMPLETE,
+ BR_INCREFS,
+ BR_ACQUIRE,
+ BR_RELEASE,
+ BR_DECREFS,
+ BR_NOOP,
+ BR_SPAWN_LOOPER,
+ BR_DEAD_BINDER,
+ BR_CLEAR_DEATH_NOTIFICATION_DONE,
+ BR_FAILED_REPLY
+);
+
+pub_no_prefix!(
+ binder_driver_command_protocol_,
+ BC_TRANSACTION,
+ BC_REPLY,
+ BC_FREE_BUFFER,
+ BC_INCREFS,
+ BC_ACQUIRE,
+ BC_RELEASE,
+ BC_DECREFS,
+ BC_INCREFS_DONE,
+ BC_ACQUIRE_DONE,
+ BC_REGISTER_LOOPER,
+ BC_ENTER_LOOPER,
+ BC_EXIT_LOOPER,
+ BC_REQUEST_DEATH_NOTIFICATION,
+ BC_CLEAR_DEATH_NOTIFICATION,
+ BC_DEAD_BINDER_DONE
+);
+
+pub_no_prefix!(transaction_flags_, TF_ONE_WAY, TF_ACCEPT_FDS);
+
+pub(crate) use bindings::{
+ BINDER_TYPE_BINDER, BINDER_TYPE_FD, BINDER_TYPE_HANDLE, BINDER_TYPE_WEAK_BINDER,
+ BINDER_TYPE_WEAK_HANDLE, FLAT_BINDER_FLAG_ACCEPTS_FDS,
+};
+
+macro_rules! decl_wrapper {
+ ($newname:ident, $wrapped:ty) => {
+ #[derive(Copy, Clone, Default)]
+ pub(crate) struct $newname($wrapped);
+
+ // TODO: This must be justified by inspecting the type, so should live outside the macro or
+ // the macro should be somehow marked unsafe.
+ unsafe impl ReadableFromBytes for $newname {}
+ unsafe impl WritableToBytes for $newname {}
+
+ impl Deref for $newname {
+ type Target = $wrapped;
+ fn deref(&self) -> &Self::Target {
+ &self.0
+ }
+ }
+
+ impl DerefMut for $newname {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ &mut self.0
+ }
+ }
+ };
+}
+
+decl_wrapper!(BinderNodeDebugInfo, bindings::binder_node_debug_info);
+decl_wrapper!(BinderNodeInfoForRef, bindings::binder_node_info_for_ref);
+decl_wrapper!(FlatBinderObject, bindings::flat_binder_object);
+decl_wrapper!(BinderTransactionData, bindings::binder_transaction_data);
+decl_wrapper!(BinderWriteRead, bindings::binder_write_read);
+decl_wrapper!(BinderVersion, bindings::binder_version);
+
+impl BinderVersion {
+ pub(crate) fn current() -> Self {
+ Self(bindings::binder_version {
+ protocol_version: bindings::BINDER_CURRENT_PROTOCOL_VERSION as _,
+ })
+ }
+}
diff --git a/drivers/android/node.rs b/drivers/android/node.rs
new file mode 100644
index 000000000000..1a46de1e736c
--- /dev/null
+++ b/drivers/android/node.rs
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::sync::atomic::{AtomicU64, Ordering};
+use kernel::{
+ io_buffer::IoBufferWriter,
+ linked_list::{GetLinks, Links, List},
+ prelude::*,
+ sync::{Guard, LockedBy, Mutex, Ref, SpinLock},
+ user_ptr::UserSlicePtrWriter,
+};
+
+use crate::{
+ defs::*,
+ process::{Process, ProcessInner},
+ thread::{BinderError, BinderResult, Thread},
+ DeliverToRead,
+};
+
+struct CountState {
+ count: usize,
+ has_count: bool,
+ is_biased: bool,
+}
+
+impl CountState {
+ fn new() -> Self {
+ Self {
+ count: 0,
+ has_count: false,
+ is_biased: false,
+ }
+ }
+
+ fn add_bias(&mut self) {
+ self.count += 1;
+ self.is_biased = true;
+ }
+}
+
+struct NodeInner {
+ strong: CountState,
+ weak: CountState,
+ death_list: List<Ref<NodeDeath>>,
+}
+
+struct NodeDeathInner {
+ dead: bool,
+ cleared: bool,
+ notification_done: bool,
+
+ /// Indicates whether the normal flow was interrupted by removing the handle. In this case, we
+ /// need behave as if the death notification didn't exist (i.e., we don't deliver anything to
+ /// the user.
+ aborted: bool,
+}
+
+pub(crate) struct NodeDeath {
+ node: Ref<Node>,
+ process: Ref<Process>,
+ // TODO: Make this private.
+ pub(crate) cookie: usize,
+ work_links: Links<dyn DeliverToRead>,
+ // TODO: Add the moment we're using this for two lists, which isn't safe because we want to
+ // remove from the list without knowing the list it's in. We need to separate this out.
+ death_links: Links<NodeDeath>,
+ inner: SpinLock<NodeDeathInner>,
+}
+
+impl NodeDeath {
+ /// Constructs a new node death notification object.
+ ///
+ /// # Safety
+ ///
+ /// The caller must call `NodeDeath::init` before using the notification object.
+ pub(crate) unsafe fn new(node: Ref<Node>, process: Ref<Process>, cookie: usize) -> Self {
+ Self {
+ node,
+ process,
+ cookie,
+ work_links: Links::new(),
+ death_links: Links::new(),
+ inner: unsafe {
+ SpinLock::new(NodeDeathInner {
+ dead: false,
+ cleared: false,
+ notification_done: false,
+ aborted: false,
+ })
+ },
+ }
+ }
+
+ pub(crate) fn init(self: Pin<&mut Self>) {
+ // SAFETY: `inner` is pinned when `self` is.
+ let inner = unsafe { self.map_unchecked_mut(|n| &mut n.inner) };
+ kernel::spinlock_init!(inner, "NodeDeath::inner");
+ }
+
+ /// Sets the cleared flag to `true`.
+ ///
+ /// It removes `self` from the node's death notification list if needed. It must only be called
+ /// once.
+ ///
+ /// Returns whether it needs to be queued.
+ pub(crate) fn set_cleared(self: &Ref<Self>, abort: bool) -> bool {
+ let (needs_removal, needs_queueing) = {
+ // Update state and determine if we need to queue a work item. We only need to do it
+ // when the node is not dead or if the user already completed the death notification.
+ let mut inner = self.inner.lock();
+ inner.cleared = true;
+ if abort {
+ inner.aborted = true;
+ }
+ (!inner.dead, !inner.dead || inner.notification_done)
+ };
+
+ // Remove death notification from node.
+ if needs_removal {
+ let mut owner_inner = self.node.owner.inner.lock();
+ let node_inner = self.node.inner.access_mut(&mut owner_inner);
+ unsafe { node_inner.death_list.remove(self) };
+ }
+
+ needs_queueing
+ }
+
+ /// Sets the 'notification done' flag to `true`.
+ ///
+ /// Returns whether it needs to be queued.
+ pub(crate) fn set_notification_done(self: Ref<Self>, thread: &Thread) {
+ let needs_queueing = {
+ let mut inner = self.inner.lock();
+ inner.notification_done = true;
+ inner.cleared
+ };
+
+ if needs_queueing {
+ let _ = thread.push_work_if_looper(self);
+ }
+ }
+
+ /// Sets the 'dead' flag to `true` and queues work item if needed.
+ pub(crate) fn set_dead(self: Ref<Self>) {
+ let needs_queueing = {
+ let mut inner = self.inner.lock();
+ if inner.cleared {
+ false
+ } else {
+ inner.dead = true;
+ true
+ }
+ };
+
+ if needs_queueing {
+ // Push the death notification to the target process. There is nothing else to do if
+ // it's already dead.
+ let process = self.process.clone();
+ let _ = process.push_work(self);
+ }
+ }
+}
+
+impl GetLinks for NodeDeath {
+ type EntryType = NodeDeath;
+ fn get_links(data: &NodeDeath) -> &Links<NodeDeath> {
+ &data.death_links
+ }
+}
+
+impl DeliverToRead for NodeDeath {
+ fn do_work(self: Ref<Self>, _thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+ let done = {
+ let inner = self.inner.lock();
+ if inner.aborted {
+ return Ok(true);
+ }
+ inner.cleared && (!inner.dead || inner.notification_done)
+ };
+
+ let cookie = self.cookie;
+ let cmd = if done {
+ BR_CLEAR_DEATH_NOTIFICATION_DONE
+ } else {
+ let process = self.process.clone();
+ let mut process_inner = process.inner.lock();
+ let inner = self.inner.lock();
+ if inner.aborted {
+ return Ok(true);
+ }
+ // We're still holding the inner lock, so it cannot be aborted while we insert it into
+ // the delivered list.
+ process_inner.death_delivered(self.clone());
+ BR_DEAD_BINDER
+ };
+
+ writer.write(&cmd)?;
+ writer.write(&cookie)?;
+
+ // Mimic the original code: we stop processing work items when we get to a death
+ // notification.
+ Ok(cmd != BR_DEAD_BINDER)
+ }
+
+ fn get_links(&self) -> &Links<dyn DeliverToRead> {
+ &self.work_links
+ }
+}
+
+pub(crate) struct Node {
+ pub(crate) global_id: u64,
+ ptr: usize,
+ cookie: usize,
+ pub(crate) flags: u32,
+ pub(crate) owner: Ref<Process>,
+ inner: LockedBy<NodeInner, Mutex<ProcessInner>>,
+ links: Links<dyn DeliverToRead>,
+}
+
+impl Node {
+ pub(crate) fn new(ptr: usize, cookie: usize, flags: u32, owner: Ref<Process>) -> Self {
+ static NEXT_ID: AtomicU64 = AtomicU64::new(1);
+ let inner = LockedBy::new(
+ &owner.inner,
+ NodeInner {
+ strong: CountState::new(),
+ weak: CountState::new(),
+ death_list: List::new(),
+ },
+ );
+ Self {
+ global_id: NEXT_ID.fetch_add(1, Ordering::Relaxed),
+ ptr,
+ cookie,
+ flags,
+ owner,
+ inner,
+ links: Links::new(),
+ }
+ }
+
+ pub(crate) fn get_id(&self) -> (usize, usize) {
+ (self.ptr, self.cookie)
+ }
+
+ pub(crate) fn next_death(
+ &self,
+ guard: &mut Guard<'_, Mutex<ProcessInner>>,
+ ) -> Option<Ref<NodeDeath>> {
+ self.inner.access_mut(guard).death_list.pop_front()
+ }
+
+ pub(crate) fn add_death(
+ &self,
+ death: Ref<NodeDeath>,
+ guard: &mut Guard<'_, Mutex<ProcessInner>>,
+ ) {
+ self.inner.access_mut(guard).death_list.push_back(death);
+ }
+
+ pub(crate) fn update_refcount_locked(
+ &self,
+ inc: bool,
+ strong: bool,
+ biased: bool,
+ owner_inner: &mut ProcessInner,
+ ) -> bool {
+ let inner = self.inner.access_from_mut(owner_inner);
+
+ // Get a reference to the state we'll update.
+ let state = if strong {
+ &mut inner.strong
+ } else {
+ &mut inner.weak
+ };
+
+ // Update biased state: if the count is not biased, there is nothing to do; otherwise,
+ // we're removing the bias, so mark the state as such.
+ if biased {
+ if !state.is_biased {
+ return false;
+ }
+
+ state.is_biased = false;
+ }
+
+ // Update the count and determine whether we need to push work.
+ // TODO: Here we may want to check the weak count being zero but the strong count being 1,
+ // because in such cases, we won't deliver anything to userspace, so we shouldn't queue
+ // either.
+ if inc {
+ state.count += 1;
+ !state.has_count
+ } else {
+ state.count -= 1;
+ state.count == 0 && state.has_count
+ }
+ }
+
+ pub(crate) fn update_refcount(self: &Ref<Self>, inc: bool, strong: bool) {
+ self.owner
+ .inner
+ .lock()
+ .update_node_refcount(self, inc, strong, false, None);
+ }
+
+ pub(crate) fn populate_counts(
+ &self,
+ out: &mut BinderNodeInfoForRef,
+ guard: &Guard<'_, Mutex<ProcessInner>>,
+ ) {
+ let inner = self.inner.access(guard);
+ out.strong_count = inner.strong.count as _;
+ out.weak_count = inner.weak.count as _;
+ }
+
+ pub(crate) fn populate_debug_info(
+ &self,
+ out: &mut BinderNodeDebugInfo,
+ guard: &Guard<'_, Mutex<ProcessInner>>,
+ ) {
+ out.ptr = self.ptr as _;
+ out.cookie = self.cookie as _;
+ let inner = self.inner.access(guard);
+ if inner.strong.has_count {
+ out.has_strong_ref = 1;
+ }
+ if inner.weak.has_count {
+ out.has_weak_ref = 1;
+ }
+ }
+
+ pub(crate) fn force_has_count(&self, guard: &mut Guard<'_, Mutex<ProcessInner>>) {
+ let inner = self.inner.access_mut(guard);
+ inner.strong.has_count = true;
+ inner.weak.has_count = true;
+ }
+
+ fn write(&self, writer: &mut UserSlicePtrWriter, code: u32) -> Result {
+ writer.write(&code)?;
+ writer.write(&self.ptr)?;
+ writer.write(&self.cookie)?;
+ Ok(())
+ }
+}
+
+impl DeliverToRead for Node {
+ fn do_work(self: Ref<Self>, _thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+ let mut owner_inner = self.owner.inner.lock();
+ let inner = self.inner.access_mut(&mut owner_inner);
+ let strong = inner.strong.count > 0;
+ let has_strong = inner.strong.has_count;
+ let weak = strong || inner.weak.count > 0;
+ let has_weak = inner.weak.has_count;
+ inner.weak.has_count = weak;
+ inner.strong.has_count = strong;
+
+ if !weak {
+ // Remove the node if there are no references to it.
+ owner_inner.remove_node(self.ptr);
+ } else {
+ if !has_weak {
+ inner.weak.add_bias();
+ }
+
+ if !has_strong && strong {
+ inner.strong.add_bias();
+ }
+ }
+
+ drop(owner_inner);
+
+ // This could be done more compactly but we write out all the posibilities for
+ // compatibility with the original implementation wrt the order of events.
+ if weak && !has_weak {
+ self.write(writer, BR_INCREFS)?;
+ }
+
+ if strong && !has_strong {
+ self.write(writer, BR_ACQUIRE)?;
+ }
+
+ if !strong && has_strong {
+ self.write(writer, BR_RELEASE)?;
+ }
+
+ if !weak && has_weak {
+ self.write(writer, BR_DECREFS)?;
+ }
+
+ Ok(true)
+ }
+
+ fn get_links(&self) -> &Links<dyn DeliverToRead> {
+ &self.links
+ }
+}
+
+pub(crate) struct NodeRef {
+ pub(crate) node: Ref<Node>,
+ strong_count: usize,
+ weak_count: usize,
+}
+
+impl NodeRef {
+ pub(crate) fn new(node: Ref<Node>, strong_count: usize, weak_count: usize) -> Self {
+ Self {
+ node,
+ strong_count,
+ weak_count,
+ }
+ }
+
+ pub(crate) fn absorb(&mut self, mut other: Self) {
+ self.strong_count += other.strong_count;
+ self.weak_count += other.weak_count;
+ other.strong_count = 0;
+ other.weak_count = 0;
+ }
+
+ pub(crate) fn clone(&self, strong: bool) -> BinderResult<NodeRef> {
+ if strong && self.strong_count == 0 {
+ return Err(BinderError::new_failed());
+ }
+
+ Ok(self
+ .node
+ .owner
+ .inner
+ .lock()
+ .new_node_ref(self.node.clone(), strong, None))
+ }
+
+ /// Updates (increments or decrements) the number of references held against the node. If the
+ /// count being updated transitions from 0 to 1 or from 1 to 0, the node is notified by having
+ /// its `update_refcount` function called.
+ ///
+ /// Returns whether `self` should be removed (when both counts are zero).
+ pub(crate) fn update(&mut self, inc: bool, strong: bool) -> bool {
+ if strong && self.strong_count == 0 {
+ return false;
+ }
+
+ let (count, other_count) = if strong {
+ (&mut self.strong_count, self.weak_count)
+ } else {
+ (&mut self.weak_count, self.strong_count)
+ };
+
+ if inc {
+ if *count == 0 {
+ self.node.update_refcount(true, strong);
+ }
+ *count += 1;
+ } else {
+ *count -= 1;
+ if *count == 0 {
+ self.node.update_refcount(false, strong);
+ return other_count == 0;
+ }
+ }
+
+ false
+ }
+}
+
+impl Drop for NodeRef {
+ fn drop(&mut self) {
+ if self.strong_count > 0 {
+ self.node.update_refcount(false, true);
+ }
+
+ if self.weak_count > 0 {
+ self.node.update_refcount(false, false);
+ }
+ }
+}
diff --git a/drivers/android/process.rs b/drivers/android/process.rs
new file mode 100644
index 000000000000..2bbe23f38ffd
--- /dev/null
+++ b/drivers/android/process.rs
@@ -0,0 +1,960 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::{convert::TryFrom, mem::take, ops::Range};
+use kernel::{
+ bindings,
+ cred::Credential,
+ file::{self, File, IoctlCommand, IoctlHandler, PollTable},
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ linked_list::List,
+ mm,
+ pages::Pages,
+ prelude::*,
+ rbtree::RBTree,
+ sync::{Guard, Mutex, Ref, RefBorrow, UniqueRef},
+ task::Task,
+ user_ptr::{UserSlicePtr, UserSlicePtrReader},
+};
+
+use crate::{
+ allocation::Allocation,
+ context::Context,
+ defs::*,
+ node::{Node, NodeDeath, NodeRef},
+ range_alloc::RangeAllocator,
+ thread::{BinderError, BinderResult, Thread},
+ DeliverToRead, DeliverToReadListAdapter, Either,
+};
+
+// TODO: Review this:
+// Lock order: Process::node_refs -> Process::inner -> Thread::inner
+
+pub(crate) struct AllocationInfo {
+ /// Range within the allocation where we can find the offsets to the object descriptors.
+ pub(crate) offsets: Range<usize>,
+}
+
+struct Mapping {
+ address: usize,
+ alloc: RangeAllocator<AllocationInfo>,
+ pages: Ref<[Pages<0>]>,
+}
+
+impl Mapping {
+ fn new(address: usize, size: usize, pages: Ref<[Pages<0>]>) -> Result<Self> {
+ let alloc = RangeAllocator::new(size)?;
+ Ok(Self {
+ address,
+ alloc,
+ pages,
+ })
+ }
+}
+
+// TODO: Make this private.
+pub(crate) struct ProcessInner {
+ is_manager: bool,
+ is_dead: bool,
+ threads: RBTree<i32, Ref<Thread>>,
+ ready_threads: List<Ref<Thread>>,
+ work: List<DeliverToReadListAdapter>,
+ mapping: Option<Mapping>,
+ nodes: RBTree<usize, Ref<Node>>,
+
+ delivered_deaths: List<Ref<NodeDeath>>,
+
+ /// The number of requested threads that haven't registered yet.
+ requested_thread_count: u32,
+
+ /// The maximum number of threads used by the process thread pool.
+ max_threads: u32,
+
+ /// The number of threads the started and registered with the thread pool.
+ started_thread_count: u32,
+}
+
+impl ProcessInner {
+ fn new() -> Self {
+ Self {
+ is_manager: false,
+ is_dead: false,
+ threads: RBTree::new(),
+ ready_threads: List::new(),
+ work: List::new(),
+ mapping: None,
+ nodes: RBTree::new(),
+ requested_thread_count: 0,
+ max_threads: 0,
+ started_thread_count: 0,
+ delivered_deaths: List::new(),
+ }
+ }
+
+ fn push_work(&mut self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+ // Try to find a ready thread to which to push the work.
+ if let Some(thread) = self.ready_threads.pop_front() {
+ // Push to thread while holding state lock. This prevents the thread from giving up
+ // (for example, because of a signal) when we're about to deliver work.
+ thread.push_work(work)
+ } else if self.is_dead {
+ Err(BinderError::new_dead())
+ } else {
+ // There are no ready threads. Push work to process queue.
+ self.work.push_back(work);
+
+ // Wake up polling threads, if any.
+ for thread in self.threads.values() {
+ thread.notify_if_poll_ready();
+ }
+ Ok(())
+ }
+ }
+
+ // TODO: Should this be private?
+ pub(crate) fn remove_node(&mut self, ptr: usize) {
+ self.nodes.remove(&ptr);
+ }
+
+ /// Updates the reference count on the given node.
+ // TODO: Decide if this should be private.
+ pub(crate) fn update_node_refcount(
+ &mut self,
+ node: &Ref<Node>,
+ inc: bool,
+ strong: bool,
+ biased: bool,
+ othread: Option<&Thread>,
+ ) {
+ let push = node.update_refcount_locked(inc, strong, biased, self);
+
+ // If we decided that we need to push work, push either to the process or to a thread if
+ // one is specified.
+ if push {
+ if let Some(thread) = othread {
+ thread.push_work_deferred(node.clone());
+ } else {
+ let _ = self.push_work(node.clone());
+ // Nothing to do: `push_work` may fail if the process is dead, but that's ok as in
+ // that case, it doesn't care about the notification.
+ }
+ }
+ }
+
+ // TODO: Make this private.
+ pub(crate) fn new_node_ref(
+ &mut self,
+ node: Ref<Node>,
+ strong: bool,
+ thread: Option<&Thread>,
+ ) -> NodeRef {
+ self.update_node_refcount(&node, true, strong, false, thread);
+ let strong_count = if strong { 1 } else { 0 };
+ NodeRef::new(node, strong_count, 1 - strong_count)
+ }
+
+ /// Returns an existing node with the given pointer and cookie, if one exists.
+ ///
+ /// Returns an error if a node with the given pointer but a different cookie exists.
+ fn get_existing_node(&self, ptr: usize, cookie: usize) -> Result<Option<Ref<Node>>> {
+ match self.nodes.get(&ptr) {
+ None => Ok(None),
+ Some(node) => {
+ let (_, node_cookie) = node.get_id();
+ if node_cookie == cookie {
+ Ok(Some(node.clone()))
+ } else {
+ Err(EINVAL)
+ }
+ }
+ }
+ }
+
+ /// Returns a reference to an existing node with the given pointer and cookie. It requires a
+ /// mutable reference because it needs to increment the ref count on the node, which may
+ /// require pushing work to the work queue (to notify userspace of 0 to 1 transitions).
+ fn get_existing_node_ref(
+ &mut self,
+ ptr: usize,
+ cookie: usize,
+ strong: bool,
+ thread: Option<&Thread>,
+ ) -> Result<Option<NodeRef>> {
+ Ok(self
+ .get_existing_node(ptr, cookie)?
+ .map(|node| self.new_node_ref(node, strong, thread)))
+ }
+
+ fn register_thread(&mut self) -> bool {
+ if self.requested_thread_count == 0 {
+ return false;
+ }
+
+ self.requested_thread_count -= 1;
+ self.started_thread_count += 1;
+ true
+ }
+
+ /// Finds a delivered death notification with the given cookie, removes it from the thread's
+ /// delivered list, and returns it.
+ fn pull_delivered_death(&mut self, cookie: usize) -> Option<Ref<NodeDeath>> {
+ let mut cursor = self.delivered_deaths.cursor_front_mut();
+ while let Some(death) = cursor.current() {
+ if death.cookie == cookie {
+ return cursor.remove_current();
+ }
+ cursor.move_next();
+ }
+ None
+ }
+
+ pub(crate) fn death_delivered(&mut self, death: Ref<NodeDeath>) {
+ self.delivered_deaths.push_back(death);
+ }
+}
+
+struct NodeRefInfo {
+ node_ref: NodeRef,
+ death: Option<Ref<NodeDeath>>,
+}
+
+impl NodeRefInfo {
+ fn new(node_ref: NodeRef) -> Self {
+ Self {
+ node_ref,
+ death: None,
+ }
+ }
+}
+
+struct ProcessNodeRefs {
+ by_handle: RBTree<u32, NodeRefInfo>,
+ by_global_id: RBTree<u64, u32>,
+}
+
+impl ProcessNodeRefs {
+ fn new() -> Self {
+ Self {
+ by_handle: RBTree::new(),
+ by_global_id: RBTree::new(),
+ }
+ }
+}
+
+pub(crate) struct Process {
+ ctx: Ref<Context>,
+
+ // The task leader (process).
+ pub(crate) task: Task,
+
+ // Credential associated with file when `Process` is created.
+ pub(crate) cred: ARef<Credential>,
+
+ // TODO: For now this a mutex because we have allocations in RangeAllocator while holding the
+ // lock. We may want to split up the process state at some point to use a spin lock for the
+ // other fields.
+ // TODO: Make this private again.
+ pub(crate) inner: Mutex<ProcessInner>,
+
+ // References are in a different mutex to avoid recursive acquisition when
+ // incrementing/decrementing a node in another process.
+ node_refs: Mutex<ProcessNodeRefs>,
+}
+
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl Send for Process {}
+unsafe impl Sync for Process {}
+
+impl Process {
+ fn new(ctx: Ref<Context>, cred: ARef<Credential>) -> Result<Ref<Self>> {
+ let mut process = Pin::from(UniqueRef::try_new(Self {
+ ctx,
+ cred,
+ task: Task::current().group_leader().clone(),
+ // SAFETY: `inner` is initialised in the call to `mutex_init` below.
+ inner: unsafe { Mutex::new(ProcessInner::new()) },
+ // SAFETY: `node_refs` is initialised in the call to `mutex_init` below.
+ node_refs: unsafe { Mutex::new(ProcessNodeRefs::new()) },
+ })?);
+
+ // SAFETY: `inner` is pinned when `Process` is.
+ let pinned = unsafe { process.as_mut().map_unchecked_mut(|p| &mut p.inner) };
+ kernel::mutex_init!(pinned, "Process::inner");
+
+ // SAFETY: `node_refs` is pinned when `Process` is.
+ let pinned = unsafe { process.as_mut().map_unchecked_mut(|p| &mut p.node_refs) };
+ kernel::mutex_init!(pinned, "Process::node_refs");
+
+ Ok(process.into())
+ }
+
+ /// Attemps to fetch a work item from the process queue.
+ pub(crate) fn get_work(&self) -> Option<Ref<dyn DeliverToRead>> {
+ self.inner.lock().work.pop_front()
+ }
+
+ /// Attemps to fetch a work item from the process queue. If none is available, it registers the
+ /// given thread as ready to receive work directly.
+ ///
+ /// This must only be called when the thread is not participating in a transaction chain; when
+ /// it is, work will always be delivered directly to the thread (and not through the process
+ /// queue).
+ pub(crate) fn get_work_or_register<'a>(
+ &'a self,
+ thread: &'a Ref<Thread>,
+ ) -> Either<Ref<dyn DeliverToRead>, Registration<'a>> {
+ let mut inner = self.inner.lock();
+
+ // Try to get work from the process queue.
+ if let Some(work) = inner.work.pop_front() {
+ return Either::Left(work);
+ }
+
+ // Register the thread as ready.
+ Either::Right(Registration::new(self, thread, &mut inner))
+ }
+
+ fn get_thread(self: RefBorrow<'_, Self>, id: i32) -> Result<Ref<Thread>> {
+ // TODO: Consider using read/write locks here instead.
+ {
+ let inner = self.inner.lock();
+ if let Some(thread) = inner.threads.get(&id) {
+ return Ok(thread.clone());
+ }
+ }
+
+ // Allocate a new `Thread` without holding any locks.
+ let ta = Thread::new(id, self.into())?;
+ let node = RBTree::try_allocate_node(id, ta.clone())?;
+
+ let mut inner = self.inner.lock();
+
+ // Recheck. It's possible the thread was create while we were not holding the lock.
+ if let Some(thread) = inner.threads.get(&id) {
+ return Ok(thread.clone());
+ }
+
+ inner.threads.insert(node);
+ Ok(ta)
+ }
+
+ pub(crate) fn push_work(&self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+ self.inner.lock().push_work(work)
+ }
+
+ fn set_as_manager(
+ self: RefBorrow<'_, Self>,
+ info: Option<FlatBinderObject>,
+ thread: &Thread,
+ ) -> Result {
+ let (ptr, cookie, flags) = if let Some(obj) = info {
+ (
+ // SAFETY: The object type for this ioctl is implicitly `BINDER_TYPE_BINDER`, so it
+ // is safe to access the `binder` field.
+ unsafe { obj.__bindgen_anon_1.binder },
+ obj.cookie,
+ obj.flags,
+ )
+ } else {
+ (0, 0, 0)
+ };
+ let node_ref = self.get_node(ptr as _, cookie as _, flags as _, true, Some(thread))?;
+ let node = node_ref.node.clone();
+ self.ctx.set_manager_node(node_ref)?;
+ self.inner.lock().is_manager = true;
+
+ // Force the state of the node to prevent the delivery of acquire/increfs.
+ let mut owner_inner = node.owner.inner.lock();
+ node.force_has_count(&mut owner_inner);
+ Ok(())
+ }
+
+ pub(crate) fn get_node(
+ self: RefBorrow<'_, Self>,
+ ptr: usize,
+ cookie: usize,
+ flags: u32,
+ strong: bool,
+ thread: Option<&Thread>,
+ ) -> Result<NodeRef> {
+ // Try to find an existing node.
+ {
+ let mut inner = self.inner.lock();
+ if let Some(node) = inner.get_existing_node_ref(ptr, cookie, strong, thread)? {
+ return Ok(node);
+ }
+ }
+
+ // Allocate the node before reacquiring the lock.
+ let node = Ref::try_new(Node::new(ptr, cookie, flags, self.into()))?;
+ let rbnode = RBTree::try_allocate_node(ptr, node.clone())?;
+
+ let mut inner = self.inner.lock();
+ if let Some(node) = inner.get_existing_node_ref(ptr, cookie, strong, thread)? {
+ return Ok(node);
+ }
+
+ inner.nodes.insert(rbnode);
+ Ok(inner.new_node_ref(node, strong, thread))
+ }
+
+ pub(crate) fn insert_or_update_handle(
+ &self,
+ node_ref: NodeRef,
+ is_mananger: bool,
+ ) -> Result<u32> {
+ {
+ let mut refs = self.node_refs.lock();
+
+ // Do a lookup before inserting.
+ if let Some(handle_ref) = refs.by_global_id.get(&node_ref.node.global_id) {
+ let handle = *handle_ref;
+ let info = refs.by_handle.get_mut(&handle).unwrap();
+ info.node_ref.absorb(node_ref);
+ return Ok(handle);
+ }
+ }
+
+ // Reserve memory for tree nodes.
+ let reserve1 = RBTree::try_reserve_node()?;
+ let reserve2 = RBTree::try_reserve_node()?;
+
+ let mut refs = self.node_refs.lock();
+
+ // Do a lookup again as node may have been inserted before the lock was reacquired.
+ if let Some(handle_ref) = refs.by_global_id.get(&node_ref.node.global_id) {
+ let handle = *handle_ref;
+ let info = refs.by_handle.get_mut(&handle).unwrap();
+ info.node_ref.absorb(node_ref);
+ return Ok(handle);
+ }
+
+ // Find id.
+ let mut target = if is_mananger { 0 } else { 1 };
+ for handle in refs.by_handle.keys() {
+ if *handle > target {
+ break;
+ }
+ if *handle == target {
+ target = target.checked_add(1).ok_or(ENOMEM)?;
+ }
+ }
+
+ // Ensure the process is still alive while we insert a new reference.
+ let inner = self.inner.lock();
+ if inner.is_dead {
+ return Err(ESRCH);
+ }
+ refs.by_global_id
+ .insert(reserve1.into_node(node_ref.node.global_id, target));
+ refs.by_handle
+ .insert(reserve2.into_node(target, NodeRefInfo::new(node_ref)));
+ Ok(target)
+ }
+
+ pub(crate) fn get_transaction_node(&self, handle: u32) -> BinderResult<NodeRef> {
+ // When handle is zero, try to get the context manager.
+ if handle == 0 {
+ self.ctx.get_manager_node(true)
+ } else {
+ self.get_node_from_handle(handle, true)
+ }
+ }
+
+ pub(crate) fn get_node_from_handle(&self, handle: u32, strong: bool) -> BinderResult<NodeRef> {
+ self.node_refs
+ .lock()
+ .by_handle
+ .get(&handle)
+ .ok_or(ENOENT)?
+ .node_ref
+ .clone(strong)
+ }
+
+ pub(crate) fn remove_from_delivered_deaths(&self, death: &Ref<NodeDeath>) {
+ let mut inner = self.inner.lock();
+ let removed = unsafe { inner.delivered_deaths.remove(death) };
+ drop(inner);
+ drop(removed);
+ }
+
+ pub(crate) fn update_ref(&self, handle: u32, inc: bool, strong: bool) -> Result {
+ if inc && handle == 0 {
+ if let Ok(node_ref) = self.ctx.get_manager_node(strong) {
+ if core::ptr::eq(self, &*node_ref.node.owner) {
+ return Err(EINVAL);
+ }
+ let _ = self.insert_or_update_handle(node_ref, true);
+ return Ok(());
+ }
+ }
+
+ // To preserve original binder behaviour, we only fail requests where the manager tries to
+ // increment references on itself.
+ let mut refs = self.node_refs.lock();
+ if let Some(info) = refs.by_handle.get_mut(&handle) {
+ if info.node_ref.update(inc, strong) {
+ // Clean up death if there is one attached to this node reference.
+ if let Some(death) = info.death.take() {
+ death.set_cleared(true);
+ self.remove_from_delivered_deaths(&death);
+ }
+
+ // Remove reference from process tables.
+ let id = info.node_ref.node.global_id;
+ refs.by_handle.remove(&handle);
+ refs.by_global_id.remove(&id);
+ }
+ }
+ Ok(())
+ }
+
+ /// Decrements the refcount of the given node, if one exists.
+ pub(crate) fn update_node(&self, ptr: usize, cookie: usize, strong: bool, biased: bool) {
+ let mut inner = self.inner.lock();
+ if let Ok(Some(node)) = inner.get_existing_node(ptr, cookie) {
+ inner.update_node_refcount(&node, false, strong, biased, None);
+ }
+ }
+
+ pub(crate) fn inc_ref_done(&self, reader: &mut UserSlicePtrReader, strong: bool) -> Result {
+ let ptr = reader.read::<usize>()?;
+ let cookie = reader.read::<usize>()?;
+ self.update_node(ptr, cookie, strong, true);
+ Ok(())
+ }
+
+ pub(crate) fn buffer_alloc(&self, size: usize) -> BinderResult<Allocation<'_>> {
+ let mut inner = self.inner.lock();
+ let mapping = inner.mapping.as_mut().ok_or_else(BinderError::new_dead)?;
+
+ let offset = mapping.alloc.reserve_new(size)?;
+ Ok(Allocation::new(
+ self,
+ offset,
+ size,
+ mapping.address + offset,
+ mapping.pages.clone(),
+ ))
+ }
+
+ // TODO: Review if we want an Option or a Result.
+ pub(crate) fn buffer_get(&self, ptr: usize) -> Option<Allocation<'_>> {
+ let mut inner = self.inner.lock();
+ let mapping = inner.mapping.as_mut()?;
+ let offset = ptr.checked_sub(mapping.address)?;
+ let (size, odata) = mapping.alloc.reserve_existing(offset).ok()?;
+ let mut alloc = Allocation::new(self, offset, size, ptr, mapping.pages.clone());
+ if let Some(data) = odata {
+ alloc.set_info(data);
+ }
+ Some(alloc)
+ }
+
+ pub(crate) fn buffer_raw_free(&self, ptr: usize) {
+ let mut inner = self.inner.lock();
+ if let Some(ref mut mapping) = &mut inner.mapping {
+ if ptr < mapping.address
+ || mapping
+ .alloc
+ .reservation_abort(ptr - mapping.address)
+ .is_err()
+ {
+ pr_warn!(
+ "Pointer {:x} failed to free, base = {:x}\n",
+ ptr,
+ mapping.address
+ );
+ }
+ }
+ }
+
+ pub(crate) fn buffer_make_freeable(&self, offset: usize, data: Option<AllocationInfo>) {
+ let mut inner = self.inner.lock();
+ if let Some(ref mut mapping) = &mut inner.mapping {
+ if mapping.alloc.reservation_commit(offset, data).is_err() {
+ pr_warn!("Offset {} failed to be marked freeable\n", offset);
+ }
+ }
+ }
+
+ fn create_mapping(&self, vma: &mut mm::virt::Area) -> Result {
+ let size = core::cmp::min(vma.end() - vma.start(), bindings::SZ_4M as usize);
+ let page_count = size / kernel::PAGE_SIZE;
+
+ // Allocate and map all pages.
+ //
+ // N.B. If we fail halfway through mapping these pages, the kernel will unmap them.
+ let mut pages = Vec::new();
+ pages.try_reserve_exact(page_count)?;
+ let mut address = vma.start();
+ for _ in 0..page_count {
+ let page = Pages::<0>::new()?;
+ vma.insert_page(address, &page)?;
+ pages.try_push(page)?;
+ address += kernel::PAGE_SIZE;
+ }
+
+ let ref_pages = Ref::try_from(pages)?;
+
+ // Save pages for later.
+ let mut inner = self.inner.lock();
+ match &inner.mapping {
+ None => inner.mapping = Some(Mapping::new(vma.start(), size, ref_pages)?),
+ Some(_) => return Err(EBUSY),
+ }
+ Ok(())
+ }
+
+ fn version(&self, data: UserSlicePtr) -> Result {
+ data.writer().write(&BinderVersion::current())
+ }
+
+ pub(crate) fn register_thread(&self) -> bool {
+ self.inner.lock().register_thread()
+ }
+
+ fn remove_thread(&self, thread: Ref<Thread>) {
+ self.inner.lock().threads.remove(&thread.id);
+ thread.release();
+ }
+
+ fn set_max_threads(&self, max: u32) {
+ self.inner.lock().max_threads = max;
+ }
+
+ fn get_node_debug_info(&self, data: UserSlicePtr) -> Result {
+ let (mut reader, mut writer) = data.reader_writer();
+
+ // Read the starting point.
+ let ptr = reader.read::<BinderNodeDebugInfo>()?.ptr as usize;
+ let mut out = BinderNodeDebugInfo::default();
+
+ {
+ let inner = self.inner.lock();
+ for (node_ptr, node) in &inner.nodes {
+ if *node_ptr > ptr {
+ node.populate_debug_info(&mut out, &inner);
+ break;
+ }
+ }
+ }
+
+ writer.write(&out)
+ }
+
+ fn get_node_info_from_ref(&self, data: UserSlicePtr) -> Result {
+ let (mut reader, mut writer) = data.reader_writer();
+ let mut out = reader.read::<BinderNodeInfoForRef>()?;
+
+ if out.strong_count != 0
+ || out.weak_count != 0
+ || out.reserved1 != 0
+ || out.reserved2 != 0
+ || out.reserved3 != 0
+ {
+ return Err(EINVAL);
+ }
+
+ // Only the context manager is allowed to use this ioctl.
+ if !self.inner.lock().is_manager {
+ return Err(EPERM);
+ }
+
+ let node_ref = self
+ .get_node_from_handle(out.handle, true)
+ .or(Err(EINVAL))?;
+
+ // Get the counts from the node.
+ {
+ let owner_inner = node_ref.node.owner.inner.lock();
+ node_ref.node.populate_counts(&mut out, &owner_inner);
+ }
+
+ // Write the result back.
+ writer.write(&out)
+ }
+
+ pub(crate) fn needs_thread(&self) -> bool {
+ let mut inner = self.inner.lock();
+ let ret = inner.requested_thread_count == 0
+ && inner.ready_threads.is_empty()
+ && inner.started_thread_count < inner.max_threads;
+ if ret {
+ inner.requested_thread_count += 1
+ };
+ ret
+ }
+
+ pub(crate) fn request_death(
+ self: &Ref<Self>,
+ reader: &mut UserSlicePtrReader,
+ thread: &Thread,
+ ) -> Result {
+ let handle: u32 = reader.read()?;
+ let cookie: usize = reader.read()?;
+
+ // TODO: First two should result in error, but not the others.
+
+ // TODO: Do we care about the context manager dying?
+
+ // Queue BR_ERROR if we can't allocate memory for the death notification.
+ let death = UniqueRef::try_new_uninit().map_err(|err| {
+ thread.push_return_work(BR_ERROR);
+ err
+ })?;
+
+ let mut refs = self.node_refs.lock();
+ let info = refs.by_handle.get_mut(&handle).ok_or(EINVAL)?;
+
+ // Nothing to do if there is already a death notification request for this handle.
+ if info.death.is_some() {
+ return Ok(());
+ }
+
+ let death = {
+ let mut pinned = Pin::from(death.write(
+ // SAFETY: `init` is called below.
+ unsafe { NodeDeath::new(info.node_ref.node.clone(), self.clone(), cookie) },
+ ));
+ pinned.as_mut().init();
+ Ref::<NodeDeath>::from(pinned)
+ };
+
+ info.death = Some(death.clone());
+
+ // Register the death notification.
+ {
+ let mut owner_inner = info.node_ref.node.owner.inner.lock();
+ if owner_inner.is_dead {
+ drop(owner_inner);
+ let _ = self.push_work(death);
+ } else {
+ info.node_ref.node.add_death(death, &mut owner_inner);
+ }
+ }
+ Ok(())
+ }
+
+ pub(crate) fn clear_death(&self, reader: &mut UserSlicePtrReader, thread: &Thread) -> Result {
+ let handle: u32 = reader.read()?;
+ let cookie: usize = reader.read()?;
+
+ let mut refs = self.node_refs.lock();
+ let info = refs.by_handle.get_mut(&handle).ok_or(EINVAL)?;
+
+ let death = info.death.take().ok_or(EINVAL)?;
+ if death.cookie != cookie {
+ info.death = Some(death);
+ return Err(EINVAL);
+ }
+
+ // Update state and determine if we need to queue a work item. We only need to do it when
+ // the node is not dead or if the user already completed the death notification.
+ if death.set_cleared(false) {
+ let _ = thread.push_work_if_looper(death);
+ }
+
+ Ok(())
+ }
+
+ pub(crate) fn dead_binder_done(&self, cookie: usize, thread: &Thread) {
+ if let Some(death) = self.inner.lock().pull_delivered_death(cookie) {
+ death.set_notification_done(thread);
+ }
+ }
+}
+
+impl IoctlHandler for Process {
+ type Target<'a> = RefBorrow<'a, Process>;
+
+ fn write(
+ this: RefBorrow<'_, Process>,
+ _file: &File,
+ cmd: u32,
+ reader: &mut UserSlicePtrReader,
+ ) -> Result<i32> {
+ let thread = this.get_thread(Task::current().pid())?;
+ match cmd {
+ bindings::BINDER_SET_MAX_THREADS => this.set_max_threads(reader.read()?),
+ bindings::BINDER_SET_CONTEXT_MGR => this.set_as_manager(None, &thread)?,
+ bindings::BINDER_THREAD_EXIT => this.remove_thread(thread),
+ bindings::BINDER_SET_CONTEXT_MGR_EXT => {
+ this.set_as_manager(Some(reader.read()?), &thread)?
+ }
+ _ => return Err(EINVAL),
+ }
+ Ok(0)
+ }
+
+ fn read_write(
+ this: RefBorrow<'_, Process>,
+ file: &File,
+ cmd: u32,
+ data: UserSlicePtr,
+ ) -> Result<i32> {
+ let thread = this.get_thread(Task::current().pid())?;
+ match cmd {
+ bindings::BINDER_WRITE_READ => thread.write_read(data, file.is_blocking())?,
+ bindings::BINDER_GET_NODE_DEBUG_INFO => this.get_node_debug_info(data)?,
+ bindings::BINDER_GET_NODE_INFO_FOR_REF => this.get_node_info_from_ref(data)?,
+ bindings::BINDER_VERSION => this.version(data)?,
+ _ => return Err(EINVAL),
+ }
+ Ok(0)
+ }
+}
+
+impl file::Operations for Process {
+ type Data = Ref<Self>;
+ type OpenData = Ref<Context>;
+
+ kernel::declare_file_operations!(ioctl, compat_ioctl, mmap, poll);
+
+ fn open(ctx: &Ref<Context>, file: &File) -> Result<Self::Data> {
+ Self::new(ctx.clone(), file.cred().into())
+ }
+
+ fn release(obj: Self::Data, _file: &File) {
+ // Mark this process as dead. We'll do the same for the threads later.
+ obj.inner.lock().is_dead = true;
+
+ // If this process is the manager, unset it.
+ if obj.inner.lock().is_manager {
+ obj.ctx.unset_manager_node();
+ }
+
+ // TODO: Do this in a worker?
+
+ // Cancel all pending work items.
+ while let Some(work) = obj.get_work() {
+ work.cancel();
+ }
+
+ // Free any resources kept alive by allocated buffers.
+ let omapping = obj.inner.lock().mapping.take();
+ if let Some(mut mapping) = omapping {
+ let address = mapping.address;
+ let pages = mapping.pages.clone();
+ mapping.alloc.for_each(|offset, size, odata| {
+ let ptr = offset + address;
+ let mut alloc = Allocation::new(&obj, offset, size, ptr, pages.clone());
+ if let Some(data) = odata {
+ alloc.set_info(data);
+ }
+ drop(alloc)
+ });
+ }
+
+ // Drop all references. We do this dance with `swap` to avoid destroying the references
+ // while holding the lock.
+ let mut refs = obj.node_refs.lock();
+ let mut node_refs = take(&mut refs.by_handle);
+ drop(refs);
+
+ // Remove all death notifications from the nodes (that belong to a different process).
+ for info in node_refs.values_mut() {
+ let death = if let Some(existing) = info.death.take() {
+ existing
+ } else {
+ continue;
+ };
+
+ death.set_cleared(false);
+ }
+
+ // Do similar dance for the state lock.
+ let mut inner = obj.inner.lock();
+ let threads = take(&mut inner.threads);
+ let nodes = take(&mut inner.nodes);
+ drop(inner);
+
+ // Release all threads.
+ for thread in threads.values() {
+ thread.release();
+ }
+
+ // Deliver death notifications.
+ for node in nodes.values() {
+ loop {
+ let death = {
+ let mut inner = obj.inner.lock();
+ if let Some(death) = node.next_death(&mut inner) {
+ death
+ } else {
+ break;
+ }
+ };
+
+ death.set_dead();
+ }
+ }
+ }
+
+ fn ioctl(this: RefBorrow<'_, Process>, file: &File, cmd: &mut IoctlCommand) -> Result<i32> {
+ cmd.dispatch::<Self>(this, file)
+ }
+
+ fn compat_ioctl(
+ this: RefBorrow<'_, Process>,
+ file: &File,
+ cmd: &mut IoctlCommand,
+ ) -> Result<i32> {
+ cmd.dispatch::<Self>(this, file)
+ }
+
+ fn mmap(this: RefBorrow<'_, Process>, _file: &File, vma: &mut mm::virt::Area) -> Result {
+ // We don't allow mmap to be used in a different process.
+ if !Task::current().group_leader().eq(&this.task) {
+ return Err(EINVAL);
+ }
+
+ if vma.start() == 0 {
+ return Err(EINVAL);
+ }
+
+ let mut flags = vma.flags();
+ use mm::virt::flags::*;
+ if flags & WRITE != 0 {
+ return Err(EPERM);
+ }
+
+ flags |= DONTCOPY | MIXEDMAP;
+ flags &= !MAYWRITE;
+ vma.set_flags(flags);
+
+ // TODO: Set ops. We need to learn when the user unmaps so that we can stop using it.
+ this.create_mapping(vma)
+ }
+
+ fn poll(this: RefBorrow<'_, Process>, file: &File, table: &PollTable) -> Result<u32> {
+ let thread = this.get_thread(Task::current().pid())?;
+ let (from_proc, mut mask) = thread.poll(file, table);
+ if mask == 0 && from_proc && !this.inner.lock().work.is_empty() {
+ mask |= bindings::POLLIN;
+ }
+ Ok(mask)
+ }
+}
+
+pub(crate) struct Registration<'a> {
+ process: &'a Process,
+ thread: &'a Ref<Thread>,
+}
+
+impl<'a> Registration<'a> {
+ fn new(
+ process: &'a Process,
+ thread: &'a Ref<Thread>,
+ guard: &mut Guard<'_, Mutex<ProcessInner>>,
+ ) -> Self {
+ guard.ready_threads.push_back(thread.clone());
+ Self { process, thread }
+ }
+}
+
+impl Drop for Registration<'_> {
+ fn drop(&mut self) {
+ let mut inner = self.process.inner.lock();
+ unsafe { inner.ready_threads.remove(self.thread) };
+ }
+}
diff --git a/drivers/android/range_alloc.rs b/drivers/android/range_alloc.rs
new file mode 100644
index 000000000000..7b149048879b
--- /dev/null
+++ b/drivers/android/range_alloc.rs
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::ptr::NonNull;
+use kernel::{
+ linked_list::{CursorMut, GetLinks, Links, List},
+ prelude::*,
+};
+
+pub(crate) struct RangeAllocator<T> {
+ list: List<Box<Descriptor<T>>>,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum DescriptorState {
+ Free,
+ Reserved,
+ Allocated,
+}
+
+impl<T> RangeAllocator<T> {
+ pub(crate) fn new(size: usize) -> Result<Self> {
+ let desc = Box::try_new(Descriptor::new(0, size))?;
+ let mut list = List::new();
+ list.push_back(desc);
+ Ok(Self { list })
+ }
+
+ fn find_best_match(&self, size: usize) -> Option<NonNull<Descriptor<T>>> {
+ // TODO: Use a binary tree instead of list for this lookup.
+ let mut best = None;
+ let mut best_size = usize::MAX;
+ let mut cursor = self.list.cursor_front();
+ while let Some(desc) = cursor.current() {
+ if desc.state == DescriptorState::Free {
+ if size == desc.size {
+ return Some(NonNull::from(desc));
+ }
+
+ if size < desc.size && desc.size < best_size {
+ best = Some(NonNull::from(desc));
+ best_size = desc.size;
+ }
+ }
+
+ cursor.move_next();
+ }
+ best
+ }
+
+ pub(crate) fn reserve_new(&mut self, size: usize) -> Result<usize> {
+ let desc_ptr = match self.find_best_match(size) {
+ None => return Err(ENOMEM),
+ Some(found) => found,
+ };
+
+ // SAFETY: We hold the only mutable reference to list, so it cannot have changed.
+ let desc = unsafe { &mut *desc_ptr.as_ptr() };
+ if desc.size == size {
+ desc.state = DescriptorState::Reserved;
+ return Ok(desc.offset);
+ }
+
+ // We need to break up the descriptor.
+ let new = Box::try_new(Descriptor::new(desc.offset + size, desc.size - size))?;
+ unsafe { self.list.insert_after(desc_ptr, new) };
+ desc.state = DescriptorState::Reserved;
+ desc.size = size;
+ Ok(desc.offset)
+ }
+
+ fn free_with_cursor(cursor: &mut CursorMut<'_, Box<Descriptor<T>>>) -> Result {
+ let mut size = match cursor.current() {
+ None => return Err(EINVAL),
+ Some(ref mut entry) => {
+ match entry.state {
+ DescriptorState::Free => return Err(EINVAL),
+ DescriptorState::Allocated => return Err(EPERM),
+ DescriptorState::Reserved => {}
+ }
+ entry.state = DescriptorState::Free;
+ entry.size
+ }
+ };
+
+ // Try to merge with the next entry.
+ if let Some(next) = cursor.peek_next() {
+ if next.state == DescriptorState::Free {
+ next.offset -= size;
+ next.size += size;
+ size = next.size;
+ cursor.remove_current();
+ }
+ }
+
+ // Try to merge with the previous entry.
+ if let Some(prev) = cursor.peek_prev() {
+ if prev.state == DescriptorState::Free {
+ prev.size += size;
+ cursor.remove_current();
+ }
+ }
+
+ Ok(())
+ }
+
+ fn find_at_offset(&mut self, offset: usize) -> Option<CursorMut<'_, Box<Descriptor<T>>>> {
+ let mut cursor = self.list.cursor_front_mut();
+ while let Some(desc) = cursor.current() {
+ if desc.offset == offset {
+ return Some(cursor);
+ }
+
+ if desc.offset > offset {
+ return None;
+ }
+
+ cursor.move_next();
+ }
+ None
+ }
+
+ pub(crate) fn reservation_abort(&mut self, offset: usize) -> Result {
+ // TODO: The force case is currently O(n), but could be made O(1) with unsafe.
+ let mut cursor = self.find_at_offset(offset).ok_or(EINVAL)?;
+ Self::free_with_cursor(&mut cursor)
+ }
+
+ pub(crate) fn reservation_commit(&mut self, offset: usize, data: Option<T>) -> Result {
+ // TODO: This is currently O(n), make it O(1).
+ let mut cursor = self.find_at_offset(offset).ok_or(ENOENT)?;
+ let desc = cursor.current().unwrap();
+ desc.state = DescriptorState::Allocated;
+ desc.data = data;
+ Ok(())
+ }
+
+ /// Takes an entry at the given offset from [`DescriptorState::Allocated`] to
+ /// [`DescriptorState::Reserved`].
+ ///
+ /// Returns the size of the existing entry and the data associated with it.
+ pub(crate) fn reserve_existing(&mut self, offset: usize) -> Result<(usize, Option<T>)> {
+ // TODO: This is currently O(n), make it O(log n).
+ let mut cursor = self.find_at_offset(offset).ok_or(ENOENT)?;
+ let desc = cursor.current().unwrap();
+ if desc.state != DescriptorState::Allocated {
+ return Err(ENOENT);
+ }
+ desc.state = DescriptorState::Reserved;
+ Ok((desc.size, desc.data.take()))
+ }
+
+ pub(crate) fn for_each<F: Fn(usize, usize, Option<T>)>(&mut self, callback: F) {
+ let mut cursor = self.list.cursor_front_mut();
+ while let Some(desc) = cursor.current() {
+ if desc.state == DescriptorState::Allocated {
+ callback(desc.offset, desc.size, desc.data.take());
+ }
+
+ cursor.move_next();
+ }
+ }
+}
+
+struct Descriptor<T> {
+ state: DescriptorState,
+ size: usize,
+ offset: usize,
+ links: Links<Descriptor<T>>,
+ data: Option<T>,
+}
+
+impl<T> Descriptor<T> {
+ fn new(offset: usize, size: usize) -> Self {
+ Self {
+ size,
+ offset,
+ state: DescriptorState::Free,
+ links: Links::new(),
+ data: None,
+ }
+ }
+}
+
+impl<T> GetLinks for Descriptor<T> {
+ type EntryType = Self;
+ fn get_links(desc: &Self) -> &Links<Self> {
+ &desc.links
+ }
+}
diff --git a/drivers/android/rust_binder.rs b/drivers/android/rust_binder.rs
new file mode 100644
index 000000000000..7158f1fdbc31
--- /dev/null
+++ b/drivers/android/rust_binder.rs
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Binder -- the Android IPC mechanism.
+//!
+//! TODO: This module is a work in progress.
+
+use kernel::{
+ io_buffer::IoBufferWriter,
+ linked_list::{GetLinks, GetLinksWrapped, Links},
+ miscdev::Registration,
+ prelude::*,
+ str::CStr,
+ sync::Ref,
+ user_ptr::UserSlicePtrWriter,
+};
+
+mod allocation;
+mod context;
+mod defs;
+mod node;
+mod process;
+mod range_alloc;
+mod thread;
+mod transaction;
+
+use {context::Context, thread::Thread};
+
+module! {
+ type: BinderModule,
+ name: b"rust_binder",
+ author: b"Wedson Almeida Filho",
+ description: b"Android Binder",
+ license: b"GPL v2",
+}
+
+enum Either<L, R> {
+ Left(L),
+ Right(R),
+}
+
+trait DeliverToRead {
+ /// Performs work. Returns true if remaining work items in the queue should be processed
+ /// immediately, or false if it should return to caller before processing additional work
+ /// items.
+ fn do_work(self: Ref<Self>, thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool>;
+
+ /// Cancels the given work item. This is called instead of [`DeliverToRead::do_work`] when work
+ /// won't be delivered.
+ fn cancel(self: Ref<Self>) {}
+
+ /// Returns the linked list links for the work item.
+ fn get_links(&self) -> &Links<dyn DeliverToRead>;
+}
+
+struct DeliverToReadListAdapter {}
+
+impl GetLinks for DeliverToReadListAdapter {
+ type EntryType = dyn DeliverToRead;
+
+ fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+ data.get_links()
+ }
+}
+
+impl GetLinksWrapped for DeliverToReadListAdapter {
+ type Wrapped = Ref<dyn DeliverToRead>;
+}
+
+struct DeliverCode {
+ code: u32,
+ links: Links<dyn DeliverToRead>,
+}
+
+impl DeliverCode {
+ fn new(code: u32) -> Self {
+ Self {
+ code,
+ links: Links::new(),
+ }
+ }
+}
+
+impl DeliverToRead for DeliverCode {
+ fn do_work(self: Ref<Self>, _thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+ writer.write(&self.code)?;
+ Ok(true)
+ }
+
+ fn get_links(&self) -> &Links<dyn DeliverToRead> {
+ &self.links
+ }
+}
+
+const fn ptr_align(value: usize) -> usize {
+ let size = core::mem::size_of::<usize>() - 1;
+ (value + size) & !size
+}
+
+unsafe impl Sync for BinderModule {}
+
+struct BinderModule {
+ _reg: Pin<Box<Registration<process::Process>>>,
+}
+
+impl kernel::Module for BinderModule {
+ fn init(name: &'static CStr, _module: &'static kernel::ThisModule) -> Result<Self> {
+ let ctx = Context::new()?;
+ let reg = Registration::new_pinned(fmt!("{name}"), ctx)?;
+ Ok(Self { _reg: reg })
+ }
+}
diff --git a/drivers/android/thread.rs b/drivers/android/thread.rs
new file mode 100644
index 000000000000..2b4d27af8ad1
--- /dev/null
+++ b/drivers/android/thread.rs
@@ -0,0 +1,870 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::{
+ alloc::AllocError,
+ mem::size_of,
+ sync::atomic::{AtomicU32, Ordering},
+};
+use kernel::{
+ bindings,
+ file::{File, PollTable},
+ io_buffer::{IoBufferReader, IoBufferWriter},
+ linked_list::{GetLinks, Links, List},
+ prelude::*,
+ security,
+ sync::{CondVar, Ref, SpinLock, UniqueRef},
+ user_ptr::{UserSlicePtr, UserSlicePtrWriter},
+};
+
+use crate::{
+ allocation::{Allocation, AllocationView},
+ defs::*,
+ process::{AllocationInfo, Process},
+ ptr_align,
+ transaction::{FileInfo, Transaction},
+ DeliverCode, DeliverToRead, DeliverToReadListAdapter, Either,
+};
+
+pub(crate) type BinderResult<T = ()> = core::result::Result<T, BinderError>;
+
+pub(crate) struct BinderError {
+ pub(crate) reply: u32,
+}
+
+impl BinderError {
+ pub(crate) fn new_failed() -> Self {
+ Self {
+ reply: BR_FAILED_REPLY,
+ }
+ }
+
+ pub(crate) fn new_dead() -> Self {
+ Self {
+ reply: BR_DEAD_REPLY,
+ }
+ }
+}
+
+impl From<Error> for BinderError {
+ fn from(_: Error) -> Self {
+ Self::new_failed()
+ }
+}
+
+impl From<AllocError> for BinderError {
+ fn from(_: AllocError) -> Self {
+ Self::new_failed()
+ }
+}
+
+const LOOPER_REGISTERED: u32 = 0x01;
+const LOOPER_ENTERED: u32 = 0x02;
+const LOOPER_EXITED: u32 = 0x04;
+const LOOPER_INVALID: u32 = 0x08;
+const LOOPER_WAITING: u32 = 0x10;
+const LOOPER_POLL: u32 = 0x20;
+
+struct InnerThread {
+ /// Determines the looper state of the thread. It is a bit-wise combination of the constants
+ /// prefixed with `LOOPER_`.
+ looper_flags: u32,
+
+ /// Determines if thread is dead.
+ is_dead: bool,
+
+ /// Work item used to deliver error codes to the thread that started a transaction. When set to
+ /// `Some(x)`, it will hold the only reference to the object so that it can update the error
+ /// code to be delivered before queuing it.
+ reply_work: Option<Ref<ThreadError>>,
+
+ /// Work item used to deliver error codes to the current thread. When set to `Some(x)`, it will
+ /// hold the only reference to the object so that it can update the error code to be delivered
+ /// before queuing.
+ return_work: Option<Ref<ThreadError>>,
+
+ /// Determines whether the work list below should be processed. When set to false, `work_list`
+ /// is treated as if it were empty.
+ process_work_list: bool,
+ work_list: List<DeliverToReadListAdapter>,
+ current_transaction: Option<Ref<Transaction>>,
+}
+
+impl InnerThread {
+ fn new() -> Self {
+ Self {
+ looper_flags: 0,
+ is_dead: false,
+ process_work_list: false,
+ work_list: List::new(),
+ current_transaction: None,
+ return_work: None,
+ reply_work: None,
+ }
+ }
+
+ fn set_reply_work(&mut self, reply_work: Ref<ThreadError>) {
+ self.reply_work = Some(reply_work);
+ }
+
+ fn push_reply_work(&mut self, code: u32) {
+ let work = self.reply_work.take();
+ self.push_existing_work(work, code);
+ }
+
+ fn set_return_work(&mut self, return_work: Ref<ThreadError>) {
+ self.return_work = Some(return_work);
+ }
+
+ fn push_return_work(&mut self, code: u32) {
+ let work = self.return_work.take();
+ self.push_existing_work(work, code);
+ }
+
+ fn push_existing_work(&mut self, owork: Option<Ref<ThreadError>>, code: u32) {
+ // TODO: Write some warning when the following fails. It should not happen, and
+ // if it does, there is likely something wrong.
+ if let Some(work) = owork {
+ // `error_code` is written to with relaxed semantics because the queue onto which it is
+ // being inserted is protected by a lock. The release barrier when the lock is released
+ // by the caller matches with the acquire barrier of the future reader to guarantee
+ // that `error_code` is visible.
+ work.error_code.store(code, Ordering::Relaxed);
+ self.push_work(work);
+ }
+ }
+
+ fn pop_work(&mut self) -> Option<Ref<dyn DeliverToRead>> {
+ if !self.process_work_list {
+ return None;
+ }
+
+ let ret = self.work_list.pop_front();
+ // Once the queue is drained, we stop processing it until a non-deferred item is pushed
+ // again onto it.
+ self.process_work_list = !self.work_list.is_empty();
+ ret
+ }
+
+ fn push_work_deferred(&mut self, work: Ref<dyn DeliverToRead>) {
+ self.work_list.push_back(work);
+ }
+
+ fn push_work(&mut self, work: Ref<dyn DeliverToRead>) {
+ self.push_work_deferred(work);
+ self.process_work_list = true;
+ }
+
+ fn has_work(&self) -> bool {
+ self.process_work_list && !self.work_list.is_empty()
+ }
+
+ /// Fetches the transaction the thread can reply to. If the thread has a pending transaction
+ /// (that it could respond to) but it has also issued a transaction, it must first wait for the
+ /// previously-issued transaction to complete.
+ fn pop_transaction_to_reply(&mut self, thread: &Thread) -> Result<Ref<Transaction>> {
+ let transaction = self.current_transaction.take().ok_or(EINVAL)?;
+
+ if core::ptr::eq(thread, transaction.from.as_ref()) {
+ self.current_transaction = Some(transaction);
+ return Err(EINVAL);
+ }
+
+ // Find a new current transaction for this thread.
+ self.current_transaction = transaction.find_from(thread);
+ Ok(transaction)
+ }
+
+ fn pop_transaction_replied(&mut self, transaction: &Ref<Transaction>) -> bool {
+ match self.current_transaction.take() {
+ None => false,
+ Some(old) => {
+ if !Ref::ptr_eq(transaction, &old) {
+ self.current_transaction = Some(old);
+ return false;
+ }
+ self.current_transaction = old.clone_next();
+ true
+ }
+ }
+ }
+
+ fn looper_enter(&mut self) {
+ self.looper_flags |= LOOPER_ENTERED;
+ if self.looper_flags & LOOPER_REGISTERED != 0 {
+ self.looper_flags |= LOOPER_INVALID;
+ }
+ }
+
+ fn looper_register(&mut self, valid: bool) {
+ self.looper_flags |= LOOPER_REGISTERED;
+ if !valid || self.looper_flags & LOOPER_ENTERED != 0 {
+ self.looper_flags |= LOOPER_INVALID;
+ }
+ }
+
+ fn looper_exit(&mut self) {
+ self.looper_flags |= LOOPER_EXITED;
+ }
+
+ /// Determines whether the thread is part of a pool, i.e., if it is a looper.
+ fn is_looper(&self) -> bool {
+ self.looper_flags & (LOOPER_ENTERED | LOOPER_REGISTERED) != 0
+ }
+
+ /// Determines whether the thread should attempt to fetch work items from the process queue
+ /// (when its own queue is empty). This is case when the thread is not part of a transaction
+ /// stack and it is registered as a looper.
+ fn should_use_process_work_queue(&self) -> bool {
+ self.current_transaction.is_none() && self.is_looper()
+ }
+
+ fn poll(&mut self) -> u32 {
+ self.looper_flags |= LOOPER_POLL;
+ if self.has_work() {
+ bindings::POLLIN
+ } else {
+ 0
+ }
+ }
+}
+
+pub(crate) struct Thread {
+ pub(crate) id: i32,
+ pub(crate) process: Ref<Process>,
+ inner: SpinLock<InnerThread>,
+ work_condvar: CondVar,
+ links: Links<Thread>,
+}
+
+impl Thread {
+ pub(crate) fn new(id: i32, process: Ref<Process>) -> Result<Ref<Self>> {
+ let return_work = Ref::try_new(ThreadError::new(InnerThread::set_return_work))?;
+ let reply_work = Ref::try_new(ThreadError::new(InnerThread::set_reply_work))?;
+ let mut thread = Pin::from(UniqueRef::try_new(Self {
+ id,
+ process,
+ // SAFETY: `inner` is initialised in the call to `spinlock_init` below.
+ inner: unsafe { SpinLock::new(InnerThread::new()) },
+ // SAFETY: `work_condvar` is initalised in the call to `condvar_init` below.
+ work_condvar: unsafe { CondVar::new() },
+ links: Links::new(),
+ })?);
+
+ // SAFETY: `inner` is pinned when `thread` is.
+ let inner = unsafe { thread.as_mut().map_unchecked_mut(|t| &mut t.inner) };
+ kernel::spinlock_init!(inner, "Thread::inner");
+
+ // SAFETY: `work_condvar` is pinned when `thread` is.
+ let condvar = unsafe { thread.as_mut().map_unchecked_mut(|t| &mut t.work_condvar) };
+ kernel::condvar_init!(condvar, "Thread::work_condvar");
+
+ {
+ let mut inner = thread.inner.lock();
+ inner.set_reply_work(reply_work);
+ inner.set_return_work(return_work);
+ }
+
+ Ok(thread.into())
+ }
+
+ pub(crate) fn set_current_transaction(&self, transaction: Ref<Transaction>) {
+ self.inner.lock().current_transaction = Some(transaction);
+ }
+
+ /// Attempts to fetch a work item from the thread-local queue. The behaviour if the queue is
+ /// empty depends on `wait`: if it is true, the function waits for some work to be queued (or a
+ /// signal); otherwise it returns indicating that none is available.
+ fn get_work_local(self: &Ref<Self>, wait: bool) -> Result<Ref<dyn DeliverToRead>> {
+ // Try once if the caller does not want to wait.
+ if !wait {
+ return self.inner.lock().pop_work().ok_or(EAGAIN);
+ }
+
+ // Loop waiting only on the local queue (i.e., not registering with the process queue).
+ let mut inner = self.inner.lock();
+ loop {
+ if let Some(work) = inner.pop_work() {
+ return Ok(work);
+ }
+
+ inner.looper_flags |= LOOPER_WAITING;
+ let signal_pending = self.work_condvar.wait(&mut inner);
+ inner.looper_flags &= !LOOPER_WAITING;
+
+ if signal_pending {
+ return Err(ERESTARTSYS);
+ }
+ }
+ }
+
+ /// Attempts to fetch a work item from the thread-local queue, falling back to the process-wide
+ /// queue if none is available locally.
+ ///
+ /// This must only be called when the thread is not participating in a transaction chain. If it
+ /// is, the local version (`get_work_local`) should be used instead.
+ fn get_work(self: &Ref<Self>, wait: bool) -> Result<Ref<dyn DeliverToRead>> {
+ // Try to get work from the thread's work queue, using only a local lock.
+ {
+ let mut inner = self.inner.lock();
+ if let Some(work) = inner.pop_work() {
+ return Ok(work);
+ }
+ }
+
+ // If the caller doesn't want to wait, try to grab work from the process queue.
+ //
+ // We know nothing will have been queued directly to the thread queue because it is not in
+ // a transaction and it is not in the process' ready list.
+ if !wait {
+ return self.process.get_work().ok_or(EAGAIN);
+ }
+
+ // Get work from the process queue. If none is available, atomically register as ready.
+ let reg = match self.process.get_work_or_register(self) {
+ Either::Left(work) => return Ok(work),
+ Either::Right(reg) => reg,
+ };
+
+ let mut inner = self.inner.lock();
+ loop {
+ if let Some(work) = inner.pop_work() {
+ return Ok(work);
+ }
+
+ inner.looper_flags |= LOOPER_WAITING;
+ let signal_pending = self.work_condvar.wait(&mut inner);
+ inner.looper_flags &= !LOOPER_WAITING;
+
+ if signal_pending {
+ // A signal is pending. We need to pull the thread off the list, then check the
+ // state again after it's off the list to ensure that something was not queued in
+ // the meantime. If something has been queued, we just return it (instead of the
+ // error).
+ drop(inner);
+ drop(reg);
+ return self.inner.lock().pop_work().ok_or(ERESTARTSYS);
+ }
+ }
+ }
+
+ pub(crate) fn push_work(&self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+ {
+ let mut inner = self.inner.lock();
+ if inner.is_dead {
+ return Err(BinderError::new_dead());
+ }
+ inner.push_work(work);
+ }
+ self.work_condvar.notify_one();
+ Ok(())
+ }
+
+ /// Attempts to push to given work item to the thread if it's a looper thread (i.e., if it's
+ /// part of a thread pool) and is alive. Otherwise, push the work item to the process instead.
+ pub(crate) fn push_work_if_looper(&self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+ let mut inner = self.inner.lock();
+ if inner.is_looper() && !inner.is_dead {
+ inner.push_work(work);
+ Ok(())
+ } else {
+ drop(inner);
+ self.process.push_work(work)
+ }
+ }
+
+ pub(crate) fn push_work_deferred(&self, work: Ref<dyn DeliverToRead>) {
+ self.inner.lock().push_work_deferred(work);
+ }
+
+ fn translate_object(
+ &self,
+ index_offset: usize,
+ view: &mut AllocationView<'_, '_>,
+ allow_fds: bool,
+ ) -> BinderResult {
+ let offset = view.alloc.read(index_offset)?;
+ let header = view.read::<bindings::binder_object_header>(offset)?;
+ // TODO: Handle other types.
+ match header.type_ {
+ BINDER_TYPE_WEAK_BINDER | BINDER_TYPE_BINDER => {
+ let strong = header.type_ == BINDER_TYPE_BINDER;
+ view.transfer_binder_object(offset, strong, |obj| {
+ // SAFETY: `binder` is a `binder_uintptr_t`; any bit pattern is a valid
+ // representation.
+ let ptr = unsafe { obj.__bindgen_anon_1.binder } as _;
+ let cookie = obj.cookie as _;
+ let flags = obj.flags as _;
+ let node = self.process.as_ref_borrow().get_node(
+ ptr,
+ cookie,
+ flags,
+ strong,
+ Some(self),
+ )?;
+ security::binder_transfer_binder(&self.process.cred, &view.alloc.process.cred)?;
+ Ok(node)
+ })?;
+ }
+ BINDER_TYPE_WEAK_HANDLE | BINDER_TYPE_HANDLE => {
+ let strong = header.type_ == BINDER_TYPE_HANDLE;
+ view.transfer_binder_object(offset, strong, |obj| {
+ // SAFETY: `handle` is a `u32`; any bit pattern is a valid representation.
+ let handle = unsafe { obj.__bindgen_anon_1.handle } as _;
+ let node = self.process.get_node_from_handle(handle, strong)?;
+ security::binder_transfer_binder(&self.process.cred, &view.alloc.process.cred)?;
+ Ok(node)
+ })?;
+ }
+ BINDER_TYPE_FD => {
+ if !allow_fds {
+ return Err(BinderError::new_failed());
+ }
+
+ let obj = view.read::<bindings::binder_fd_object>(offset)?;
+ // SAFETY: `fd` is a `u32`; any bit pattern is a valid representation.
+ let fd = unsafe { obj.__bindgen_anon_1.fd };
+ let file = File::from_fd(fd)?;
+ security::binder_transfer_file(
+ &self.process.cred,
+ &view.alloc.process.cred,
+ &file,
+ )?;
+ let field_offset =
+ kernel::offset_of!(bindings::binder_fd_object, __bindgen_anon_1.fd) as usize;
+ let file_info = Box::try_new(FileInfo::new(file, offset + field_offset))?;
+ view.alloc.add_file_info(file_info);
+ }
+ _ => pr_warn!("Unsupported binder object type: {:x}\n", header.type_),
+ }
+ Ok(())
+ }
+
+ fn translate_objects(
+ &self,
+ alloc: &mut Allocation<'_>,
+ start: usize,
+ end: usize,
+ allow_fds: bool,
+ ) -> BinderResult {
+ let mut view = AllocationView::new(alloc, start);
+ for i in (start..end).step_by(size_of::<usize>()) {
+ if let Err(err) = self.translate_object(i, &mut view, allow_fds) {
+ alloc.set_info(AllocationInfo { offsets: start..i });
+ return Err(err);
+ }
+ }
+ alloc.set_info(AllocationInfo {
+ offsets: start..end,
+ });
+ Ok(())
+ }
+
+ pub(crate) fn copy_transaction_data<'a>(
+ &self,
+ to_process: &'a Process,
+ tr: &BinderTransactionData,
+ allow_fds: bool,
+ ) -> BinderResult<Allocation<'a>> {
+ let data_size = tr.data_size as _;
+ let adata_size = ptr_align(data_size);
+ let offsets_size = tr.offsets_size as _;
+ let aoffsets_size = ptr_align(offsets_size);
+
+ // This guarantees that at least `sizeof(usize)` bytes will be allocated.
+ let len = core::cmp::max(
+ adata_size.checked_add(aoffsets_size).ok_or(ENOMEM)?,
+ size_of::<usize>(),
+ );
+ let mut alloc = to_process.buffer_alloc(len)?;
+
+ // Copy raw data.
+ let mut reader = unsafe { UserSlicePtr::new(tr.data.ptr.buffer as _, data_size) }.reader();
+ alloc.copy_into(&mut reader, 0, data_size)?;
+
+ // Copy offsets if there are any.
+ if offsets_size > 0 {
+ let mut reader =
+ unsafe { UserSlicePtr::new(tr.data.ptr.offsets as _, offsets_size) }.reader();
+ alloc.copy_into(&mut reader, adata_size, offsets_size)?;
+
+ // Traverse the objects specified.
+ self.translate_objects(
+ &mut alloc,
+ adata_size,
+ adata_size + aoffsets_size,
+ allow_fds,
+ )?;
+ }
+
+ Ok(alloc)
+ }
+
+ fn unwind_transaction_stack(self: &Ref<Self>) {
+ let mut thread = self.clone();
+ while let Ok(transaction) = {
+ let mut inner = thread.inner.lock();
+ inner.pop_transaction_to_reply(thread.as_ref())
+ } {
+ let reply = Either::Right(BR_DEAD_REPLY);
+ if !transaction.from.deliver_single_reply(reply, &transaction) {
+ break;
+ }
+
+ thread = transaction.from.clone();
+ }
+ }
+
+ pub(crate) fn deliver_reply(
+ &self,
+ reply: Either<Ref<Transaction>, u32>,
+ transaction: &Ref<Transaction>,
+ ) {
+ if self.deliver_single_reply(reply, transaction) {
+ transaction.from.unwind_transaction_stack();
+ }
+ }
+
+ /// Delivers a reply to the thread that started a transaction. The reply can either be a
+ /// reply-transaction or an error code to be delivered instead.
+ ///
+ /// Returns whether the thread is dead. If it is, the caller is expected to unwind the
+ /// transaction stack by completing transactions for threads that are dead.
+ fn deliver_single_reply(
+ &self,
+ reply: Either<Ref<Transaction>, u32>,
+ transaction: &Ref<Transaction>,
+ ) -> bool {
+ {
+ let mut inner = self.inner.lock();
+ if !inner.pop_transaction_replied(transaction) {
+ return false;
+ }
+
+ if inner.is_dead {
+ return true;
+ }
+
+ match reply {
+ Either::Left(work) => inner.push_work(work),
+ Either::Right(code) => inner.push_reply_work(code),
+ }
+ }
+
+ // Notify the thread now that we've released the inner lock.
+ self.work_condvar.notify_one();
+ false
+ }
+
+ /// Determines if the given transaction is the current transaction for this thread.
+ fn is_current_transaction(&self, transaction: &Ref<Transaction>) -> bool {
+ let inner = self.inner.lock();
+ match &inner.current_transaction {
+ None => false,
+ Some(current) => Ref::ptr_eq(current, transaction),
+ }
+ }
+
+ fn transaction<T>(self: &Ref<Self>, tr: &BinderTransactionData, inner: T)
+ where
+ T: FnOnce(&Ref<Self>, &BinderTransactionData) -> BinderResult,
+ {
+ if let Err(err) = inner(self, tr) {
+ self.inner.lock().push_return_work(err.reply);
+ }
+ }
+
+ fn reply_inner(self: &Ref<Self>, tr: &BinderTransactionData) -> BinderResult {
+ let orig = self.inner.lock().pop_transaction_to_reply(self)?;
+ if !orig.from.is_current_transaction(&orig) {
+ return Err(BinderError::new_failed());
+ }
+
+ // We need to complete the transaction even if we cannot complete building the reply.
+ (|| -> BinderResult<_> {
+ let completion = Ref::try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
+ let process = orig.from.process.clone();
+ let allow_fds = orig.flags & TF_ACCEPT_FDS != 0;
+ let reply = Transaction::new_reply(self, process, tr, allow_fds)?;
+ self.inner.lock().push_work(completion);
+ orig.from.deliver_reply(Either::Left(reply), &orig);
+ Ok(())
+ })()
+ .map_err(|mut err| {
+ // At this point we only return `BR_TRANSACTION_COMPLETE` to the caller, and we must let
+ // the sender know that the transaction has completed (with an error in this case).
+ let reply = Either::Right(BR_FAILED_REPLY);
+ orig.from.deliver_reply(reply, &orig);
+ err.reply = BR_TRANSACTION_COMPLETE;
+ err
+ })
+ }
+
+ /// Determines the current top of the transaction stack. It fails if the top is in another
+ /// thread (i.e., this thread belongs to a stack but it has called another thread). The top is
+ /// [`None`] if the thread is not currently participating in a transaction stack.
+ fn top_of_transaction_stack(&self) -> Result<Option<Ref<Transaction>>> {
+ let inner = self.inner.lock();
+ Ok(if let Some(cur) = &inner.current_transaction {
+ if core::ptr::eq(self, cur.from.as_ref()) {
+ return Err(EINVAL);
+ }
+ Some(cur.clone())
+ } else {
+ None
+ })
+ }
+
+ fn oneway_transaction_inner(self: &Ref<Self>, tr: &BinderTransactionData) -> BinderResult {
+ let handle = unsafe { tr.target.handle };
+ let node_ref = self.process.get_transaction_node(handle)?;
+ security::binder_transaction(&self.process.cred, &node_ref.node.owner.cred)?;
+ let completion = Ref::try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
+ let transaction = Transaction::new(node_ref, None, self, tr)?;
+ self.inner.lock().push_work(completion);
+ // TODO: Remove the completion on error?
+ transaction.submit()?;
+ Ok(())
+ }
+
+ fn transaction_inner(self: &Ref<Self>, tr: &BinderTransactionData) -> BinderResult {
+ let handle = unsafe { tr.target.handle };
+ let node_ref = self.process.get_transaction_node(handle)?;
+ security::binder_transaction(&self.process.cred, &node_ref.node.owner.cred)?;
+ // TODO: We need to ensure that there isn't a pending transaction in the work queue. How
+ // could this happen?
+ let top = self.top_of_transaction_stack()?;
+ let completion = Ref::try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
+ let transaction = Transaction::new(node_ref, top, self, tr)?;
+
+ // Check that the transaction stack hasn't changed while the lock was released, then update
+ // it with the new transaction.
+ {
+ let mut inner = self.inner.lock();
+ if !transaction.is_stacked_on(&inner.current_transaction) {
+ return Err(BinderError::new_failed());
+ }
+ inner.current_transaction = Some(transaction.clone());
+ }
+
+ // We push the completion as a deferred work so that we wait for the reply before returning
+ // to userland.
+ self.push_work_deferred(completion);
+ // TODO: Remove completion if submission fails?
+ transaction.submit()?;
+ Ok(())
+ }
+
+ fn write(self: &Ref<Self>, req: &mut BinderWriteRead) -> Result {
+ let write_start = req.write_buffer.wrapping_add(req.write_consumed);
+ let write_len = req.write_size - req.write_consumed;
+ let mut reader = unsafe { UserSlicePtr::new(write_start as _, write_len as _).reader() };
+
+ while reader.len() >= size_of::<u32>() && self.inner.lock().return_work.is_some() {
+ let before = reader.len();
+ match reader.read::<u32>()? {
+ BC_TRANSACTION => {
+ let tr = reader.read::<BinderTransactionData>()?;
+ if tr.flags & TF_ONE_WAY != 0 {
+ self.transaction(&tr, Self::oneway_transaction_inner)
+ } else {
+ self.transaction(&tr, Self::transaction_inner)
+ }
+ }
+ BC_REPLY => self.transaction(&reader.read()?, Self::reply_inner),
+ BC_FREE_BUFFER => drop(self.process.buffer_get(reader.read()?)),
+ BC_INCREFS => self.process.update_ref(reader.read()?, true, false)?,
+ BC_ACQUIRE => self.process.update_ref(reader.read()?, true, true)?,
+ BC_RELEASE => self.process.update_ref(reader.read()?, false, true)?,
+ BC_DECREFS => self.process.update_ref(reader.read()?, false, false)?,
+ BC_INCREFS_DONE => self.process.inc_ref_done(&mut reader, false)?,
+ BC_ACQUIRE_DONE => self.process.inc_ref_done(&mut reader, true)?,
+ BC_REQUEST_DEATH_NOTIFICATION => self.process.request_death(&mut reader, self)?,
+ BC_CLEAR_DEATH_NOTIFICATION => self.process.clear_death(&mut reader, self)?,
+ BC_DEAD_BINDER_DONE => self.process.dead_binder_done(reader.read()?, self),
+ BC_REGISTER_LOOPER => {
+ let valid = self.process.register_thread();
+ self.inner.lock().looper_register(valid);
+ }
+ BC_ENTER_LOOPER => self.inner.lock().looper_enter(),
+ BC_EXIT_LOOPER => self.inner.lock().looper_exit(),
+
+ // TODO: Add support for BC_TRANSACTION_SG and BC_REPLY_SG.
+ // BC_ATTEMPT_ACQUIRE and BC_ACQUIRE_RESULT are no longer supported.
+ _ => return Err(EINVAL),
+ }
+
+ // Update the number of write bytes consumed.
+ req.write_consumed += (before - reader.len()) as u64;
+ }
+ Ok(())
+ }
+
+ fn read(self: &Ref<Self>, req: &mut BinderWriteRead, wait: bool) -> Result {
+ let read_start = req.read_buffer.wrapping_add(req.read_consumed);
+ let read_len = req.read_size - req.read_consumed;
+ let mut writer = unsafe { UserSlicePtr::new(read_start as _, read_len as _) }.writer();
+ let (in_pool, getter) = {
+ let inner = self.inner.lock();
+ (
+ inner.is_looper(),
+ if inner.should_use_process_work_queue() {
+ Self::get_work
+ } else {
+ Self::get_work_local
+ },
+ )
+ };
+
+ // Reserve some room at the beginning of the read buffer so that we can send a
+ // BR_SPAWN_LOOPER if we need to.
+ if req.read_consumed == 0 {
+ writer.write(&BR_NOOP)?;
+ }
+
+ // Loop doing work while there is room in the buffer.
+ let initial_len = writer.len();
+ while writer.len() >= size_of::<u32>() {
+ match getter(self, wait && initial_len == writer.len()) {
+ Ok(work) => {
+ if !work.do_work(self, &mut writer)? {
+ break;
+ }
+ }
+ Err(err) => {
+ // Propagate the error if we haven't written anything else.
+ if initial_len == writer.len() {
+ return Err(err);
+ } else {
+ break;
+ }
+ }
+ }
+ }
+
+ req.read_consumed += read_len - writer.len() as u64;
+
+ // Write BR_SPAWN_LOOPER if the process needs more threads for its pool.
+ if in_pool && self.process.needs_thread() {
+ let mut writer =
+ unsafe { UserSlicePtr::new(req.read_buffer as _, req.read_size as _) }.writer();
+ writer.write(&BR_SPAWN_LOOPER)?;
+ }
+
+ Ok(())
+ }
+
+ pub(crate) fn write_read(self: &Ref<Self>, data: UserSlicePtr, wait: bool) -> Result {
+ let (mut reader, mut writer) = data.reader_writer();
+ let mut req = reader.read::<BinderWriteRead>()?;
+
+ // TODO: `write(&req)` happens in all exit paths from here on. Find a better way to encode
+ // it.
+
+ // Go through the write buffer.
+ if req.write_size > 0 {
+ if let Err(err) = self.write(&mut req) {
+ req.read_consumed = 0;
+ writer.write(&req)?;
+ return Err(err);
+ }
+ }
+
+ // Go through the work queue.
+ let mut ret = Ok(());
+ if req.read_size > 0 {
+ ret = self.read(&mut req, wait);
+ }
+
+ // Write the request back so that the consumed fields are visible to the caller.
+ writer.write(&req)?;
+ ret
+ }
+
+ pub(crate) fn poll(&self, file: &File, table: &PollTable) -> (bool, u32) {
+ // SAFETY: `free_waiters` is called on release.
+ unsafe { table.register_wait(file, &self.work_condvar) };
+ let mut inner = self.inner.lock();
+ (inner.should_use_process_work_queue(), inner.poll())
+ }
+
+ pub(crate) fn notify_if_poll_ready(&self) {
+ // Determine if we need to notify. This requires the lock.
+ let inner = self.inner.lock();
+ let notify = inner.looper_flags & LOOPER_POLL != 0
+ && inner.should_use_process_work_queue()
+ && !inner.has_work();
+ drop(inner);
+
+ // Now that the lock is no longer held, notify the waiters if we have to.
+ if notify {
+ self.work_condvar.notify_one();
+ }
+ }
+
+ pub(crate) fn push_return_work(&self, code: u32) {
+ self.inner.lock().push_return_work(code)
+ }
+
+ pub(crate) fn release(self: &Ref<Self>) {
+ // Mark the thread as dead.
+ self.inner.lock().is_dead = true;
+
+ // Cancel all pending work items.
+ while let Ok(work) = self.get_work_local(false) {
+ work.cancel();
+ }
+
+ // Complete the transaction stack as far as we can.
+ self.unwind_transaction_stack();
+
+ // Remove epoll items if polling was ever used on the thread.
+ let poller = self.inner.lock().looper_flags & LOOPER_POLL != 0;
+ if poller {
+ self.work_condvar.free_waiters();
+
+ unsafe { bindings::synchronize_rcu() };
+ }
+ }
+}
+
+impl GetLinks for Thread {
+ type EntryType = Thread;
+ fn get_links(data: &Thread) -> &Links<Thread> {
+ &data.links
+ }
+}
+
+struct ThreadError {
+ error_code: AtomicU32,
+ return_fn: fn(&mut InnerThread, Ref<ThreadError>),
+ links: Links<dyn DeliverToRead>,
+}
+
+impl ThreadError {
+ fn new(return_fn: fn(&mut InnerThread, Ref<ThreadError>)) -> Self {
+ Self {
+ error_code: AtomicU32::new(BR_OK),
+ return_fn,
+ links: Links::new(),
+ }
+ }
+}
+
+impl DeliverToRead for ThreadError {
+ fn do_work(self: Ref<Self>, thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+ // See `ThreadInner::push_existing_work` for the reason why `error_code` is up to date even
+ // though we use relaxed semantics.
+ let code = self.error_code.load(Ordering::Relaxed);
+
+ // Return the `ThreadError` to the thread.
+ (self.return_fn)(&mut *thread.inner.lock(), self);
+
+ // Deliver the error code to userspace.
+ writer.write(&code)?;
+ Ok(true)
+ }
+
+ fn get_links(&self) -> &Links<dyn DeliverToRead> {
+ &self.links
+ }
+}
diff --git a/drivers/android/transaction.rs b/drivers/android/transaction.rs
new file mode 100644
index 000000000000..8ddf6e21c9cd
--- /dev/null
+++ b/drivers/android/transaction.rs
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::sync::atomic::{AtomicBool, Ordering};
+use kernel::{
+ bindings,
+ file::{File, FileDescriptorReservation},
+ io_buffer::IoBufferWriter,
+ linked_list::List,
+ linked_list::{GetLinks, Links},
+ prelude::*,
+ sync::{Ref, SpinLock, UniqueRef},
+ user_ptr::UserSlicePtrWriter,
+ ScopeGuard,
+};
+
+use crate::{
+ defs::*,
+ node::NodeRef,
+ process::Process,
+ ptr_align,
+ thread::{BinderResult, Thread},
+ DeliverToRead, Either,
+};
+
+struct TransactionInner {
+ file_list: List<Box<FileInfo>>,
+}
+
+pub(crate) struct Transaction {
+ inner: SpinLock<TransactionInner>,
+ // TODO: Node should be released when the buffer is released.
+ node_ref: Option<NodeRef>,
+ stack_next: Option<Ref<Transaction>>,
+ pub(crate) from: Ref<Thread>,
+ to: Ref<Process>,
+ free_allocation: AtomicBool,
+ code: u32,
+ pub(crate) flags: u32,
+ data_size: usize,
+ offsets_size: usize,
+ data_address: usize,
+ links: Links<dyn DeliverToRead>,
+}
+
+impl Transaction {
+ pub(crate) fn new(
+ node_ref: NodeRef,
+ stack_next: Option<Ref<Transaction>>,
+ from: &Ref<Thread>,
+ tr: &BinderTransactionData,
+ ) -> BinderResult<Ref<Self>> {
+ let allow_fds = node_ref.node.flags & FLAT_BINDER_FLAG_ACCEPTS_FDS != 0;
+ let to = node_ref.node.owner.clone();
+ let mut alloc = from.copy_transaction_data(&to, tr, allow_fds)?;
+ let data_address = alloc.ptr;
+ let file_list = alloc.take_file_list();
+ alloc.keep_alive();
+ let mut tr = Pin::from(UniqueRef::try_new(Self {
+ // SAFETY: `spinlock_init` is called below.
+ inner: unsafe { SpinLock::new(TransactionInner { file_list }) },
+ node_ref: Some(node_ref),
+ stack_next,
+ from: from.clone(),
+ to,
+ code: tr.code,
+ flags: tr.flags,
+ data_size: tr.data_size as _,
+ data_address,
+ offsets_size: tr.offsets_size as _,
+ links: Links::new(),
+ free_allocation: AtomicBool::new(true),
+ })?);
+
+ // SAFETY: `inner` is pinned when `tr` is.
+ let pinned = unsafe { tr.as_mut().map_unchecked_mut(|t| &mut t.inner) };
+ kernel::spinlock_init!(pinned, "Transaction::inner");
+
+ Ok(tr.into())
+ }
+
+ pub(crate) fn new_reply(
+ from: &Ref<Thread>,
+ to: Ref<Process>,
+ tr: &BinderTransactionData,
+ allow_fds: bool,
+ ) -> BinderResult<Ref<Self>> {
+ let mut alloc = from.copy_transaction_data(&to, tr, allow_fds)?;
+ let data_address = alloc.ptr;
+ let file_list = alloc.take_file_list();
+ alloc.keep_alive();
+ let mut tr = Pin::from(UniqueRef::try_new(Self {
+ // SAFETY: `spinlock_init` is called below.
+ inner: unsafe { SpinLock::new(TransactionInner { file_list }) },
+ node_ref: None,
+ stack_next: None,
+ from: from.clone(),
+ to,
+ code: tr.code,
+ flags: tr.flags,
+ data_size: tr.data_size as _,
+ data_address,
+ offsets_size: tr.offsets_size as _,
+ links: Links::new(),
+ free_allocation: AtomicBool::new(true),
+ })?);
+
+ // SAFETY: `inner` is pinned when `tr` is.
+ let pinned = unsafe { tr.as_mut().map_unchecked_mut(|t| &mut t.inner) };
+ kernel::spinlock_init!(pinned, "Transaction::inner");
+
+ Ok(tr.into())
+ }
+
+ /// Determines if the transaction is stacked on top of the given transaction.
+ pub(crate) fn is_stacked_on(&self, onext: &Option<Ref<Self>>) -> bool {
+ match (&self.stack_next, onext) {
+ (None, None) => true,
+ (Some(stack_next), Some(next)) => Ref::ptr_eq(stack_next, next),
+ _ => false,
+ }
+ }
+
+ /// Returns a pointer to the next transaction on the transaction stack, if there is one.
+ pub(crate) fn clone_next(&self) -> Option<Ref<Self>> {
+ let next = self.stack_next.as_ref()?;
+ Some(next.clone())
+ }
+
+ /// Searches in the transaction stack for a thread that belongs to the target process. This is
+ /// useful when finding a target for a new transaction: if the node belongs to a process that
+ /// is already part of the transaction stack, we reuse the thread.
+ fn find_target_thread(&self) -> Option<Ref<Thread>> {
+ let process = &self.node_ref.as_ref()?.node.owner;
+
+ let mut it = &self.stack_next;
+ while let Some(transaction) = it {
+ if Ref::ptr_eq(&transaction.from.process, process) {
+ return Some(transaction.from.clone());
+ }
+ it = &transaction.stack_next;
+ }
+ None
+ }
+
+ /// Searches in the transaction stack for a transaction originating at the given thread.
+ pub(crate) fn find_from(&self, thread: &Thread) -> Option<Ref<Transaction>> {
+ let mut it = &self.stack_next;
+ while let Some(transaction) = it {
+ if core::ptr::eq(thread, transaction.from.as_ref()) {
+ return Some(transaction.clone());
+ }
+
+ it = &transaction.stack_next;
+ }
+ None
+ }
+
+ /// Submits the transaction to a work queue. Use a thread if there is one in the transaction
+ /// stack, otherwise use the destination process.
+ pub(crate) fn submit(self: Ref<Self>) -> BinderResult {
+ if let Some(thread) = self.find_target_thread() {
+ thread.push_work(self)
+ } else {
+ let process = self.to.clone();
+ process.push_work(self)
+ }
+ }
+
+ /// Prepares the file list for delivery to the caller.
+ fn prepare_file_list(&self) -> Result<List<Box<FileInfo>>> {
+ // Get list of files that are being transferred as part of the transaction.
+ let mut file_list = core::mem::replace(&mut self.inner.lock().file_list, List::new());
+
+ // If the list is non-empty, prepare the buffer.
+ if !file_list.is_empty() {
+ let alloc = self.to.buffer_get(self.data_address).ok_or(ESRCH)?;
+ let cleanup = ScopeGuard::new(|| {
+ self.free_allocation.store(false, Ordering::Relaxed);
+ });
+
+ let mut it = file_list.cursor_front_mut();
+ while let Some(file_info) = it.current() {
+ let reservation = FileDescriptorReservation::new(bindings::O_CLOEXEC)?;
+ alloc.write(file_info.buffer_offset, &reservation.reserved_fd())?;
+ file_info.reservation = Some(reservation);
+ it.move_next();
+ }
+
+ alloc.keep_alive();
+ cleanup.dismiss();
+ }
+
+ Ok(file_list)
+ }
+}
+
+impl DeliverToRead for Transaction {
+ fn do_work(self: Ref<Self>, thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+ /* TODO: Initialise the following fields from tr:
+ pub sender_pid: pid_t,
+ pub sender_euid: uid_t,
+ */
+ let send_failed_reply = ScopeGuard::new(|| {
+ if self.node_ref.is_some() && self.flags & TF_ONE_WAY == 0 {
+ let reply = Either::Right(BR_FAILED_REPLY);
+ self.from.deliver_reply(reply, &self);
+ }
+ });
+ let mut file_list = if let Ok(list) = self.prepare_file_list() {
+ list
+ } else {
+ // On failure to process the list, we send a reply back to the sender and ignore the
+ // transaction on the recipient.
+ return Ok(true);
+ };
+
+ let mut tr = BinderTransactionData::default();
+
+ if let Some(nref) = &self.node_ref {
+ let (ptr, cookie) = nref.node.get_id();
+ tr.target.ptr = ptr as _;
+ tr.cookie = cookie as _;
+ };
+
+ tr.code = self.code;
+ tr.flags = self.flags;
+ tr.data_size = self.data_size as _;
+ tr.data.ptr.buffer = self.data_address as _;
+ tr.offsets_size = self.offsets_size as _;
+ if tr.offsets_size > 0 {
+ tr.data.ptr.offsets = (self.data_address + ptr_align(self.data_size)) as _;
+ }
+
+ let code = if self.node_ref.is_none() {
+ BR_REPLY
+ } else {
+ BR_TRANSACTION
+ };
+
+ // Write the transaction code and data to the user buffer.
+ writer.write(&code)?;
+ writer.write(&tr)?;
+
+ // Dismiss the completion of transaction with a failure. No failure paths are allowed from
+ // here on out.
+ send_failed_reply.dismiss();
+
+ // Commit all files.
+ {
+ let mut it = file_list.cursor_front_mut();
+ while let Some(file_info) = it.current() {
+ if let Some(reservation) = file_info.reservation.take() {
+ if let Some(file) = file_info.file.take() {
+ reservation.commit(file);
+ }
+ }
+
+ it.move_next();
+ }
+ }
+
+ // When `drop` is called, we don't want the allocation to be freed because it is now the
+ // user's reponsibility to free it.
+ //
+ // `drop` is guaranteed to see this relaxed store because `Ref` guarantess that everything
+ // that happens when an object is referenced happens-before the eventual `drop`.
+ self.free_allocation.store(false, Ordering::Relaxed);
+
+ // When this is not a reply and not an async transaction, update `current_transaction`. If
+ // it's a reply, `current_transaction` has already been updated appropriately.
+ if self.node_ref.is_some() && tr.flags & TF_ONE_WAY == 0 {
+ thread.set_current_transaction(self);
+ }
+
+ Ok(false)
+ }
+
+ fn cancel(self: Ref<Self>) {
+ let reply = Either::Right(BR_DEAD_REPLY);
+ self.from.deliver_reply(reply, &self);
+ }
+
+ fn get_links(&self) -> &Links<dyn DeliverToRead> {
+ &self.links
+ }
+}
+
+impl Drop for Transaction {
+ fn drop(&mut self) {
+ if self.free_allocation.load(Ordering::Relaxed) {
+ self.to.buffer_get(self.data_address);
+ }
+ }
+}
+
+pub(crate) struct FileInfo {
+ links: Links<FileInfo>,
+
+ /// The file for which a descriptor will be created in the recipient process.
+ file: Option<ARef<File>>,
+
+ /// The file descriptor reservation on the recipient process.
+ reservation: Option<FileDescriptorReservation>,
+
+ /// The offset in the buffer where the file descriptor is stored.
+ buffer_offset: usize,
+}
+
+impl FileInfo {
+ pub(crate) fn new(file: ARef<File>, buffer_offset: usize) -> Self {
+ Self {
+ file: Some(file),
+ reservation: None,
+ buffer_offset,
+ links: Links::new(),
+ }
+ }
+}
+
+impl GetLinks for FileInfo {
+ type EntryType = Self;
+
+ fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+ &data.links
+ }
+}
diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
index 11157fae8a8e..a982c30dbbf5 100644
--- a/include/uapi/linux/android/binder.h
+++ b/include/uapi/linux/android/binder.h
@@ -236,19 +236,21 @@ struct binder_frozen_status_info {
__u32 async_recv;
};
-#define BINDER_WRITE_READ _IOWR('b', 1, struct binder_write_read)
-#define BINDER_SET_IDLE_TIMEOUT _IOW('b', 3, __s64)
-#define BINDER_SET_MAX_THREADS _IOW('b', 5, __u32)
-#define BINDER_SET_IDLE_PRIORITY _IOW('b', 6, __s32)
-#define BINDER_SET_CONTEXT_MGR _IOW('b', 7, __s32)
-#define BINDER_THREAD_EXIT _IOW('b', 8, __s32)
-#define BINDER_VERSION _IOWR('b', 9, struct binder_version)
-#define BINDER_GET_NODE_DEBUG_INFO _IOWR('b', 11, struct binder_node_debug_info)
-#define BINDER_GET_NODE_INFO_FOR_REF _IOWR('b', 12, struct binder_node_info_for_ref)
-#define BINDER_SET_CONTEXT_MGR_EXT _IOW('b', 13, struct flat_binder_object)
-#define BINDER_FREEZE _IOW('b', 14, struct binder_freeze_info)
-#define BINDER_GET_FROZEN_INFO _IOWR('b', 15, struct binder_frozen_status_info)
-#define BINDER_ENABLE_ONEWAY_SPAM_DETECTION _IOW('b', 16, __u32)
+enum {
+ BINDER_WRITE_READ = _IOWR('b', 1, struct binder_write_read),
+ BINDER_SET_IDLE_TIMEOUT = _IOW('b', 3, __s64),
+ BINDER_SET_MAX_THREADS = _IOW('b', 5, __u32),
+ BINDER_SET_IDLE_PRIORITY = _IOW('b', 6, __s32),
+ BINDER_SET_CONTEXT_MGR = _IOW('b', 7, __s32),
+ BINDER_THREAD_EXIT = _IOW('b', 8, __s32),
+ BINDER_VERSION = _IOWR('b', 9, struct binder_version),
+ BINDER_GET_NODE_DEBUG_INFO = _IOWR('b', 11, struct binder_node_debug_info),
+ BINDER_GET_NODE_INFO_FOR_REF = _IOWR('b', 12, struct binder_node_info_for_ref),
+ BINDER_SET_CONTEXT_MGR_EXT = _IOW('b', 13, struct flat_binder_object),
+ BINDER_FREEZE = _IOW('b', 14, struct binder_freeze_info),
+ BINDER_GET_FROZEN_INFO = _IOWR('b', 15, struct binder_frozen_status_info),
+ BINDER_ENABLE_ONEWAY_SPAM_DETECTION = _IOW('b', 16, __u32),
+};
/*
* NOTE: Two special error codes you should check for when calling
--
2.35.3
This is a subset of the Rust standard library `alloc` crate,
version 1.60.0, from:
https://github.com/rust-lang/rust/tree/1.60.0/library/alloc/src
The files are copied as-is, with no modifications whatsoever
(not even adding the SPDX identifiers).
The next patch modifies these files as needed for use within
the kernel. This patch split allows reviewers to double-check
the import and to clearly see the differences introduced.
Vendoring `alloc`, at least for the moment, allows us to have fallible
allocations support (i.e. the `try_*` versions of methods which return
a `Result` instead of panicking) early on. It also gives a bit more
freedom to experiment with new interfaces and to iterate quickly.
Eventually, the goal is to have everything the kernel needs in
upstream `alloc` and drop it from the kernel tree.
For a summary of work on `alloc` happening upstream, please see:
https://github.com/Rust-for-Linux/linux/issues/408
For copyright details, please see:
https://github.com/rust-lang/rust/blob/1.60.0/COPYRIGHT
Co-developed-by: Alex Gaynor <[email protected]>
Signed-off-by: Alex Gaynor <[email protected]>
Co-developed-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Wedson Almeida Filho <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>
---
rust/alloc/alloc.rs | 436 ++++
rust/alloc/borrow.rs | 496 +++++
rust/alloc/boxed.rs | 2005 +++++++++++++++++++
rust/alloc/collections/mod.rs | 154 ++
rust/alloc/fmt.rs | 599 ++++++
rust/alloc/lib.rs | 223 +++
rust/alloc/macros.rs | 125 ++
rust/alloc/raw_vec.rs | 519 +++++
rust/alloc/slice.rs | 1191 +++++++++++
rust/alloc/str.rs | 613 ++++++
rust/alloc/string.rs | 2867 +++++++++++++++++++++++++++
rust/alloc/vec/drain.rs | 184 ++
rust/alloc/vec/drain_filter.rs | 143 ++
rust/alloc/vec/into_iter.rs | 354 ++++
rust/alloc/vec/is_zero.rs | 104 +
rust/alloc/vec/mod.rs | 3055 +++++++++++++++++++++++++++++
rust/alloc/vec/partial_eq.rs | 47 +
rust/alloc/vec/set_len_on_drop.rs | 28 +
rust/alloc/vec/spec_extend.rs | 87 +
19 files changed, 13230 insertions(+)
create mode 100644 rust/alloc/alloc.rs
create mode 100644 rust/alloc/borrow.rs
create mode 100644 rust/alloc/boxed.rs
create mode 100644 rust/alloc/collections/mod.rs
create mode 100644 rust/alloc/fmt.rs
create mode 100644 rust/alloc/lib.rs
create mode 100644 rust/alloc/macros.rs
create mode 100644 rust/alloc/raw_vec.rs
create mode 100644 rust/alloc/slice.rs
create mode 100644 rust/alloc/str.rs
create mode 100644 rust/alloc/string.rs
create mode 100644 rust/alloc/vec/drain.rs
create mode 100644 rust/alloc/vec/drain_filter.rs
create mode 100644 rust/alloc/vec/into_iter.rs
create mode 100644 rust/alloc/vec/is_zero.rs
create mode 100644 rust/alloc/vec/mod.rs
create mode 100644 rust/alloc/vec/partial_eq.rs
create mode 100644 rust/alloc/vec/set_len_on_drop.rs
create mode 100644 rust/alloc/vec/spec_extend.rs
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
new file mode 100644
index 000000000000..9d4f9af91a5e
--- /dev/null
+++ b/rust/alloc/alloc.rs
@@ -0,0 +1,436 @@
+//! Memory allocation APIs
+
+#![stable(feature = "alloc_module", since = "1.28.0")]
+
+#[cfg(not(test))]
+use core::intrinsics;
+use core::intrinsics::{min_align_of_val, size_of_val};
+
+use core::ptr::Unique;
+#[cfg(not(test))]
+use core::ptr::{self, NonNull};
+
+#[stable(feature = "alloc_module", since = "1.28.0")]
+#[doc(inline)]
+pub use core::alloc::*;
+
+#[cfg(test)]
+mod tests;
+
+extern "Rust" {
+ // These are the magic symbols to call the global allocator. rustc generates
+ // them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute
+ // (the code expanding that attribute macro generates those functions), or to call
+ // the default implementations in libstd (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
+ // otherwise.
+ // The rustc fork of LLVM also special-cases these function names to be able to optimize them
+ // like `malloc`, `realloc`, and `free`, respectively.
+ #[rustc_allocator]
+ #[rustc_allocator_nounwind]
+ fn __rust_alloc(size: usize, align: usize) -> *mut u8;
+ #[rustc_allocator_nounwind]
+ fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
+ #[rustc_allocator_nounwind]
+ fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
+ #[rustc_allocator_nounwind]
+ fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
+}
+
+/// The global memory allocator.
+///
+/// This type implements the [`Allocator`] trait by forwarding calls
+/// to the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// Note: while this type is unstable, the functionality it provides can be
+/// accessed through the [free functions in `alloc`](self#functions).
+#[unstable(feature = "allocator_api", issue = "32838")]
+#[derive(Copy, Clone, Default, Debug)]
+#[cfg(not(test))]
+pub struct Global;
+
+#[cfg(test)]
+pub use std::alloc::Global;
+
+/// Allocate memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::alloc`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `alloc` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::alloc`].
+///
+/// # Examples
+///
+/// ```
+/// use std::alloc::{alloc, dealloc, Layout};
+///
+/// unsafe {
+/// let layout = Layout::new::<u16>();
+/// let ptr = alloc(layout);
+///
+/// *(ptr as *mut u16) = 42;
+/// assert_eq!(*(ptr as *mut u16), 42);
+///
+/// dealloc(ptr, layout);
+/// }
+/// ```
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[must_use = "losing the pointer will leak memory"]
+#[inline]
+pub unsafe fn alloc(layout: Layout) -> *mut u8 {
+ unsafe { __rust_alloc(layout.size(), layout.align()) }
+}
+
+/// Deallocate memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::dealloc`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `dealloc` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::dealloc`].
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[inline]
+pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
+ unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+}
+
+/// Reallocate memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::realloc`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `realloc` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::realloc`].
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[must_use = "losing the pointer will leak memory"]
+#[inline]
+pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+ unsafe { __rust_realloc(ptr, layout.size(), layout.align(), new_size) }
+}
+
+/// Allocate zero-initialized memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::alloc_zeroed`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `alloc_zeroed` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::alloc_zeroed`].
+///
+/// # Examples
+///
+/// ```
+/// use std::alloc::{alloc_zeroed, dealloc, Layout};
+///
+/// unsafe {
+/// let layout = Layout::new::<u16>();
+/// let ptr = alloc_zeroed(layout);
+///
+/// assert_eq!(*(ptr as *mut u16), 0);
+///
+/// dealloc(ptr, layout);
+/// }
+/// ```
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[must_use = "losing the pointer will leak memory"]
+#[inline]
+pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
+ unsafe { __rust_alloc_zeroed(layout.size(), layout.align()) }
+}
+
+#[cfg(not(test))]
+impl Global {
+ #[inline]
+ fn alloc_impl(&self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocError> {
+ match layout.size() {
+ 0 => Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0)),
+ // SAFETY: `layout` is non-zero in size,
+ size => unsafe {
+ let raw_ptr = if zeroed { alloc_zeroed(layout) } else { alloc(layout) };
+ let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+ Ok(NonNull::slice_from_raw_parts(ptr, size))
+ },
+ }
+ }
+
+ // SAFETY: Same as `Allocator::grow`
+ #[inline]
+ unsafe fn grow_impl(
+ &self,
+ ptr: NonNull<u8>,
+ old_layout: Layout,
+ new_layout: Layout,
+ zeroed: bool,
+ ) -> Result<NonNull<[u8]>, AllocError> {
+ debug_assert!(
+ new_layout.size() >= old_layout.size(),
+ "`new_layout.size()` must be greater than or equal to `old_layout.size()`"
+ );
+
+ match old_layout.size() {
+ 0 => self.alloc_impl(new_layout, zeroed),
+
+ // SAFETY: `new_size` is non-zero as `old_size` is greater than or equal to `new_size`
+ // as required by safety conditions. Other conditions must be upheld by the caller
+ old_size if old_layout.align() == new_layout.align() => unsafe {
+ let new_size = new_layout.size();
+
+ // `realloc` probably checks for `new_size >= old_layout.size()` or something similar.
+ intrinsics::assume(new_size >= old_layout.size());
+
+ let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
+ let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+ if zeroed {
+ raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
+ }
+ Ok(NonNull::slice_from_raw_parts(ptr, new_size))
+ },
+
+ // SAFETY: because `new_layout.size()` must be greater than or equal to `old_size`,
+ // both the old and new memory allocation are valid for reads and writes for `old_size`
+ // bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
+ // `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
+ // for `dealloc` must be upheld by the caller.
+ old_size => unsafe {
+ let new_ptr = self.alloc_impl(new_layout, zeroed)?;
+ ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), old_size);
+ self.deallocate(ptr, old_layout);
+ Ok(new_ptr)
+ },
+ }
+ }
+}
+
+#[unstable(feature = "allocator_api", issue = "32838")]
+#[cfg(not(test))]
+unsafe impl Allocator for Global {
+ #[inline]
+ fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+ self.alloc_impl(layout, false)
+ }
+
+ #[inline]
+ fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+ self.alloc_impl(layout, true)
+ }
+
+ #[inline]
+ unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+ if layout.size() != 0 {
+ // SAFETY: `layout` is non-zero in size,
+ // other conditions must be upheld by the caller
+ unsafe { dealloc(ptr.as_ptr(), layout) }
+ }
+ }
+
+ #[inline]
+ unsafe fn grow(
+ &self,
+ ptr: NonNull<u8>,
+ old_layout: Layout,
+ new_layout: Layout,
+ ) -> Result<NonNull<[u8]>, AllocError> {
+ // SAFETY: all conditions must be upheld by the caller
+ unsafe { self.grow_impl(ptr, old_layout, new_layout, false) }
+ }
+
+ #[inline]
+ unsafe fn grow_zeroed(
+ &self,
+ ptr: NonNull<u8>,
+ old_layout: Layout,
+ new_layout: Layout,
+ ) -> Result<NonNull<[u8]>, AllocError> {
+ // SAFETY: all conditions must be upheld by the caller
+ unsafe { self.grow_impl(ptr, old_layout, new_layout, true) }
+ }
+
+ #[inline]
+ unsafe fn shrink(
+ &self,
+ ptr: NonNull<u8>,
+ old_layout: Layout,
+ new_layout: Layout,
+ ) -> Result<NonNull<[u8]>, AllocError> {
+ debug_assert!(
+ new_layout.size() <= old_layout.size(),
+ "`new_layout.size()` must be smaller than or equal to `old_layout.size()`"
+ );
+
+ match new_layout.size() {
+ // SAFETY: conditions must be upheld by the caller
+ 0 => unsafe {
+ self.deallocate(ptr, old_layout);
+ Ok(NonNull::slice_from_raw_parts(new_layout.dangling(), 0))
+ },
+
+ // SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
+ new_size if old_layout.align() == new_layout.align() => unsafe {
+ // `realloc` probably checks for `new_size <= old_layout.size()` or something similar.
+ intrinsics::assume(new_size <= old_layout.size());
+
+ let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
+ let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+ Ok(NonNull::slice_from_raw_parts(ptr, new_size))
+ },
+
+ // SAFETY: because `new_size` must be smaller than or equal to `old_layout.size()`,
+ // both the old and new memory allocation are valid for reads and writes for `new_size`
+ // bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
+ // `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
+ // for `dealloc` must be upheld by the caller.
+ new_size => unsafe {
+ let new_ptr = self.allocate(new_layout)?;
+ ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), new_size);
+ self.deallocate(ptr, old_layout);
+ Ok(new_ptr)
+ },
+ }
+ }
+}
+
+/// The allocator for unique pointers.
+#[cfg(all(not(no_global_oom_handling), not(test)))]
+#[lang = "exchange_malloc"]
+#[inline]
+unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
+ let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
+ match Global.allocate(layout) {
+ Ok(ptr) => ptr.as_mut_ptr(),
+ Err(_) => handle_alloc_error(layout),
+ }
+}
+
+#[cfg_attr(not(test), lang = "box_free")]
+#[inline]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+// This signature has to be the same as `Box`, otherwise an ICE will happen.
+// When an additional parameter to `Box` is added (like `A: Allocator`), this has to be added here as
+// well.
+// For example if `Box` is changed to `struct Box<T: ?Sized, A: Allocator>(Unique<T>, A)`,
+// this function has to be changed to `fn box_free<T: ?Sized, A: Allocator>(Unique<T>, A)` as well.
+pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Drop>(
+ ptr: Unique<T>,
+ alloc: A,
+) {
+ unsafe {
+ let size = size_of_val(ptr.as_ref());
+ let align = min_align_of_val(ptr.as_ref());
+ let layout = Layout::from_size_align_unchecked(size, align);
+ alloc.deallocate(From::from(ptr.cast()), layout)
+ }
+}
+
+// # Allocation error handler
+
+#[cfg(not(no_global_oom_handling))]
+extern "Rust" {
+ // This is the magic symbol to call the global alloc error handler. rustc generates
+ // it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
+ // default implementations below (`__rdl_oom`) otherwise.
+ fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
+}
+
+/// Abort on memory allocation error or failure.
+///
+/// Callers of memory allocation APIs wishing to abort computation
+/// in response to an allocation error are encouraged to call this function,
+/// rather than directly invoking `panic!` or similar.
+///
+/// The default behavior of this function is to print a message to standard error
+/// and abort the process.
+/// It can be replaced with [`set_alloc_error_hook`] and [`take_alloc_error_hook`].
+///
+/// [`set_alloc_error_hook`]: ../../std/alloc/fn.set_alloc_error_hook.html
+/// [`take_alloc_error_hook`]: ../../std/alloc/fn.take_alloc_error_hook.html
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[rustc_const_unstable(feature = "const_alloc_error", issue = "92523")]
+#[cfg(all(not(no_global_oom_handling), not(test)))]
+#[cold]
+pub const fn handle_alloc_error(layout: Layout) -> ! {
+ const fn ct_error(_: Layout) -> ! {
+ panic!("allocation failed");
+ }
+
+ fn rt_error(layout: Layout) -> ! {
+ unsafe {
+ __rust_alloc_error_handler(layout.size(), layout.align());
+ }
+ }
+
+ unsafe { core::intrinsics::const_eval_select((layout,), ct_error, rt_error) }
+}
+
+// For alloc test `std::alloc::handle_alloc_error` can be used directly.
+#[cfg(all(not(no_global_oom_handling), test))]
+pub use std::alloc::handle_alloc_error;
+
+#[cfg(all(not(no_global_oom_handling), not(any(target_os = "hermit", test))))]
+#[doc(hidden)]
+#[allow(unused_attributes)]
+#[unstable(feature = "alloc_internals", issue = "none")]
+pub mod __alloc_error_handler {
+ use crate::alloc::Layout;
+
+ // called via generated `__rust_alloc_error_handler`
+
+ // if there is no `#[alloc_error_handler]`
+ #[rustc_std_internal_symbol]
+ pub unsafe extern "C-unwind" fn __rdl_oom(size: usize, _align: usize) -> ! {
+ panic!("memory allocation of {} bytes failed", size)
+ }
+
+ // if there is an `#[alloc_error_handler]`
+ #[rustc_std_internal_symbol]
+ pub unsafe extern "C-unwind" fn __rg_oom(size: usize, align: usize) -> ! {
+ let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
+ extern "Rust" {
+ #[lang = "oom"]
+ fn oom_impl(layout: Layout) -> !;
+ }
+ unsafe { oom_impl(layout) }
+ }
+}
+
+/// Specialize clones into pre-allocated, uninitialized memory.
+/// Used by `Box::clone` and `Rc`/`Arc::make_mut`.
+pub(crate) trait WriteCloneIntoRaw: Sized {
+ unsafe fn write_clone_into_raw(&self, target: *mut Self);
+}
+
+impl<T: Clone> WriteCloneIntoRaw for T {
+ #[inline]
+ default unsafe fn write_clone_into_raw(&self, target: *mut Self) {
+ // Having allocated *first* may allow the optimizer to create
+ // the cloned value in-place, skipping the local and move.
+ unsafe { target.write(self.clone()) };
+ }
+}
+
+impl<T: Copy> WriteCloneIntoRaw for T {
+ #[inline]
+ unsafe fn write_clone_into_raw(&self, target: *mut Self) {
+ // We can always copy in-place, without ever involving a local value.
+ unsafe { target.copy_from_nonoverlapping(self, 1) };
+ }
+}
diff --git a/rust/alloc/borrow.rs b/rust/alloc/borrow.rs
new file mode 100644
index 000000000000..63234ee91f09
--- /dev/null
+++ b/rust/alloc/borrow.rs
@@ -0,0 +1,496 @@
+//! A module for working with borrowed data.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use core::cmp::Ordering;
+use core::hash::{Hash, Hasher};
+use core::ops::Deref;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::{Add, AddAssign};
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::borrow::{Borrow, BorrowMut};
+
+use crate::fmt;
+#[cfg(not(no_global_oom_handling))]
+use crate::string::String;
+
+use Cow::*;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: ?Sized> Borrow<B> for Cow<'a, B>
+where
+ B: ToOwned,
+ <B as ToOwned>::Owned: 'a,
+{
+ fn borrow(&self) -> &B {
+ &**self
+ }
+}
+
+/// A generalization of `Clone` to borrowed data.
+///
+/// Some types make it possible to go from borrowed to owned, usually by
+/// implementing the `Clone` trait. But `Clone` works only for going from `&T`
+/// to `T`. The `ToOwned` trait generalizes `Clone` to construct owned data
+/// from any borrow of a given type.
+#[cfg_attr(not(test), rustc_diagnostic_item = "ToOwned")]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait ToOwned {
+ /// The resulting type after obtaining ownership.
+ #[stable(feature = "rust1", since = "1.0.0")]
+ type Owned: Borrow<Self>;
+
+ /// Creates owned data from borrowed data, usually by cloning.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s: &str = "a";
+ /// let ss: String = s.to_owned();
+ ///
+ /// let v: &[i32] = &[1, 2];
+ /// let vv: Vec<i32> = v.to_owned();
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use = "cloning is often expensive and is not expected to have side effects"]
+ fn to_owned(&self) -> Self::Owned;
+
+ /// Uses borrowed data to replace owned data, usually by cloning.
+ ///
+ /// This is borrow-generalized version of `Clone::clone_from`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// # #![feature(toowned_clone_into)]
+ /// let mut s: String = String::new();
+ /// "hello".clone_into(&mut s);
+ ///
+ /// let mut v: Vec<i32> = Vec::new();
+ /// [1, 2][..].clone_into(&mut v);
+ /// ```
+ #[unstable(feature = "toowned_clone_into", reason = "recently added", issue = "41263")]
+ fn clone_into(&self, target: &mut Self::Owned) {
+ *target = self.to_owned();
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ToOwned for T
+where
+ T: Clone,
+{
+ type Owned = T;
+ fn to_owned(&self) -> T {
+ self.clone()
+ }
+
+ fn clone_into(&self, target: &mut T) {
+ target.clone_from(self);
+ }
+}
+
+/// A clone-on-write smart pointer.
+///
+/// The type `Cow` is a smart pointer providing clone-on-write functionality: it
+/// can enclose and provide immutable access to borrowed data, and clone the
+/// data lazily when mutation or ownership is required. The type is designed to
+/// work with general borrowed data via the `Borrow` trait.
+///
+/// `Cow` implements `Deref`, which means that you can call
+/// non-mutating methods directly on the data it encloses. If mutation
+/// is desired, `to_mut` will obtain a mutable reference to an owned
+/// value, cloning if necessary.
+///
+/// If you need reference-counting pointers, note that
+/// [`Rc::make_mut`][crate::rc::Rc::make_mut] and
+/// [`Arc::make_mut`][crate::sync::Arc::make_mut] can provide clone-on-write
+/// functionality as well.
+///
+/// # Examples
+///
+/// ```
+/// use std::borrow::Cow;
+///
+/// fn abs_all(input: &mut Cow<[i32]>) {
+/// for i in 0..input.len() {
+/// let v = input[i];
+/// if v < 0 {
+/// // Clones into a vector if not already owned.
+/// input.to_mut()[i] = -v;
+/// }
+/// }
+/// }
+///
+/// // No clone occurs because `input` doesn't need to be mutated.
+/// let slice = [0, 1, 2];
+/// let mut input = Cow::from(&slice[..]);
+/// abs_all(&mut input);
+///
+/// // Clone occurs because `input` needs to be mutated.
+/// let slice = [-1, 0, 1];
+/// let mut input = Cow::from(&slice[..]);
+/// abs_all(&mut input);
+///
+/// // No clone occurs because `input` is already owned.
+/// let mut input = Cow::from(vec![-1, 0, 1]);
+/// abs_all(&mut input);
+/// ```
+///
+/// Another example showing how to keep `Cow` in a struct:
+///
+/// ```
+/// use std::borrow::Cow;
+///
+/// struct Items<'a, X: 'a> where [X]: ToOwned<Owned = Vec<X>> {
+/// values: Cow<'a, [X]>,
+/// }
+///
+/// impl<'a, X: Clone + 'a> Items<'a, X> where [X]: ToOwned<Owned = Vec<X>> {
+/// fn new(v: Cow<'a, [X]>) -> Self {
+/// Items { values: v }
+/// }
+/// }
+///
+/// // Creates a container from borrowed values of a slice
+/// let readonly = [1, 2];
+/// let borrowed = Items::new((&readonly[..]).into());
+/// match borrowed {
+/// Items { values: Cow::Borrowed(b) } => println!("borrowed {:?}", b),
+/// _ => panic!("expect borrowed value"),
+/// }
+///
+/// let mut clone_on_write = borrowed;
+/// // Mutates the data from slice into owned vec and pushes a new value on top
+/// clone_on_write.values.to_mut().push(3);
+/// println!("clone_on_write = {:?}", clone_on_write.values);
+///
+/// // The data was mutated. Let's check it out.
+/// match clone_on_write {
+/// Items { values: Cow::Owned(_) } => println!("clone_on_write contains owned data"),
+/// _ => panic!("expect owned data"),
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Cow")]
+pub enum Cow<'a, B: ?Sized + 'a>
+where
+ B: ToOwned,
+{
+ /// Borrowed data.
+ #[stable(feature = "rust1", since = "1.0.0")]
+ Borrowed(#[stable(feature = "rust1", since = "1.0.0")] &'a B),
+
+ /// Owned data.
+ #[stable(feature = "rust1", since = "1.0.0")]
+ Owned(#[stable(feature = "rust1", since = "1.0.0")] <B as ToOwned>::Owned),
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized + ToOwned> Clone for Cow<'_, B> {
+ fn clone(&self) -> Self {
+ match *self {
+ Borrowed(b) => Borrowed(b),
+ Owned(ref o) => {
+ let b: &B = o.borrow();
+ Owned(b.to_owned())
+ }
+ }
+ }
+
+ fn clone_from(&mut self, source: &Self) {
+ match (self, source) {
+ (&mut Owned(ref mut dest), &Owned(ref o)) => o.borrow().clone_into(dest),
+ (t, s) => *t = s.clone(),
+ }
+ }
+}
+
+impl<B: ?Sized + ToOwned> Cow<'_, B> {
+ /// Returns true if the data is borrowed, i.e. if `to_mut` would require additional work.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(cow_is_borrowed)]
+ /// use std::borrow::Cow;
+ ///
+ /// let cow = Cow::Borrowed("moo");
+ /// assert!(cow.is_borrowed());
+ ///
+ /// let bull: Cow<'_, str> = Cow::Owned("...moo?".to_string());
+ /// assert!(!bull.is_borrowed());
+ /// ```
+ #[unstable(feature = "cow_is_borrowed", issue = "65143")]
+ #[rustc_const_unstable(feature = "const_cow_is_borrowed", issue = "65143")]
+ pub const fn is_borrowed(&self) -> bool {
+ match *self {
+ Borrowed(_) => true,
+ Owned(_) => false,
+ }
+ }
+
+ /// Returns true if the data is owned, i.e. if `to_mut` would be a no-op.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(cow_is_borrowed)]
+ /// use std::borrow::Cow;
+ ///
+ /// let cow: Cow<'_, str> = Cow::Owned("moo".to_string());
+ /// assert!(cow.is_owned());
+ ///
+ /// let bull = Cow::Borrowed("...moo?");
+ /// assert!(!bull.is_owned());
+ /// ```
+ #[unstable(feature = "cow_is_borrowed", issue = "65143")]
+ #[rustc_const_unstable(feature = "const_cow_is_borrowed", issue = "65143")]
+ pub const fn is_owned(&self) -> bool {
+ !self.is_borrowed()
+ }
+
+ /// Acquires a mutable reference to the owned form of the data.
+ ///
+ /// Clones the data if it is not already owned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::borrow::Cow;
+ ///
+ /// let mut cow = Cow::Borrowed("foo");
+ /// cow.to_mut().make_ascii_uppercase();
+ ///
+ /// assert_eq!(
+ /// cow,
+ /// Cow::Owned(String::from("FOO")) as Cow<str>
+ /// );
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn to_mut(&mut self) -> &mut <B as ToOwned>::Owned {
+ match *self {
+ Borrowed(borrowed) => {
+ *self = Owned(borrowed.to_owned());
+ match *self {
+ Borrowed(..) => unreachable!(),
+ Owned(ref mut owned) => owned,
+ }
+ }
+ Owned(ref mut owned) => owned,
+ }
+ }
+
+ /// Extracts the owned data.
+ ///
+ /// Clones the data if it is not already owned.
+ ///
+ /// # Examples
+ ///
+ /// Calling `into_owned` on a `Cow::Borrowed` clones the underlying data
+ /// and becomes a `Cow::Owned`:
+ ///
+ /// ```
+ /// use std::borrow::Cow;
+ ///
+ /// let s = "Hello world!";
+ /// let cow = Cow::Borrowed(s);
+ ///
+ /// assert_eq!(
+ /// cow.into_owned(),
+ /// String::from(s)
+ /// );
+ /// ```
+ ///
+ /// Calling `into_owned` on a `Cow::Owned` is a no-op:
+ ///
+ /// ```
+ /// use std::borrow::Cow;
+ ///
+ /// let s = "Hello world!";
+ /// let cow: Cow<str> = Cow::Owned(String::from(s));
+ ///
+ /// assert_eq!(
+ /// cow.into_owned(),
+ /// String::from(s)
+ /// );
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn into_owned(self) -> <B as ToOwned>::Owned {
+ match self {
+ Borrowed(borrowed) => borrowed.to_owned(),
+ Owned(owned) => owned,
+ }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_deref", issue = "88955")]
+impl<B: ?Sized + ToOwned> const Deref for Cow<'_, B>
+where
+ B::Owned: ~const Borrow<B>,
+{
+ type Target = B;
+
+ fn deref(&self) -> &B {
+ match *self {
+ Borrowed(borrowed) => borrowed,
+ Owned(ref owned) => owned.borrow(),
+ }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> Eq for Cow<'_, B> where B: Eq + ToOwned {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> Ord for Cow<'_, B>
+where
+ B: Ord + ToOwned,
+{
+ #[inline]
+ fn cmp(&self, other: &Self) -> Ordering {
+ Ord::cmp(&**self, &**other)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, 'b, B: ?Sized, C: ?Sized> PartialEq<Cow<'b, C>> for Cow<'a, B>
+where
+ B: PartialEq<C> + ToOwned,
+ C: ToOwned,
+{
+ #[inline]
+ fn eq(&self, other: &Cow<'b, C>) -> bool {
+ PartialEq::eq(&**self, &**other)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: ?Sized> PartialOrd for Cow<'a, B>
+where
+ B: PartialOrd + ToOwned,
+{
+ #[inline]
+ fn partial_cmp(&self, other: &Cow<'a, B>) -> Option<Ordering> {
+ PartialOrd::partial_cmp(&**self, &**other)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> fmt::Debug for Cow<'_, B>
+where
+ B: fmt::Debug + ToOwned<Owned: fmt::Debug>,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ Borrowed(ref b) => fmt::Debug::fmt(b, f),
+ Owned(ref o) => fmt::Debug::fmt(o, f),
+ }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> fmt::Display for Cow<'_, B>
+where
+ B: fmt::Display + ToOwned<Owned: fmt::Display>,
+{
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match *self {
+ Borrowed(ref b) => fmt::Display::fmt(b, f),
+ Owned(ref o) => fmt::Display::fmt(o, f),
+ }
+ }
+}
+
+#[stable(feature = "default", since = "1.11.0")]
+impl<B: ?Sized> Default for Cow<'_, B>
+where
+ B: ToOwned<Owned: Default>,
+{
+ /// Creates an owned Cow<'a, B> with the default value for the contained owned value.
+ fn default() -> Self {
+ Owned(<B as ToOwned>::Owned::default())
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> Hash for Cow<'_, B>
+where
+ B: Hash + ToOwned,
+{
+ #[inline]
+ fn hash<H: Hasher>(&self, state: &mut H) {
+ Hash::hash(&**self, state)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + ToOwned> AsRef<T> for Cow<'_, T> {
+ fn as_ref(&self) -> &T {
+ self
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> Add<&'a str> for Cow<'a, str> {
+ type Output = Cow<'a, str>;
+
+ #[inline]
+ fn add(mut self, rhs: &'a str) -> Self::Output {
+ self += rhs;
+ self
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> Add<Cow<'a, str>> for Cow<'a, str> {
+ type Output = Cow<'a, str>;
+
+ #[inline]
+ fn add(mut self, rhs: Cow<'a, str>) -> Self::Output {
+ self += rhs;
+ self
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> AddAssign<&'a str> for Cow<'a, str> {
+ fn add_assign(&mut self, rhs: &'a str) {
+ if self.is_empty() {
+ *self = Cow::Borrowed(rhs)
+ } else if !rhs.is_empty() {
+ if let Cow::Borrowed(lhs) = *self {
+ let mut s = String::with_capacity(lhs.len() + rhs.len());
+ s.push_str(lhs);
+ *self = Cow::Owned(s);
+ }
+ self.to_mut().push_str(rhs);
+ }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> AddAssign<Cow<'a, str>> for Cow<'a, str> {
+ fn add_assign(&mut self, rhs: Cow<'a, str>) {
+ if self.is_empty() {
+ *self = rhs
+ } else if !rhs.is_empty() {
+ if let Cow::Borrowed(lhs) = *self {
+ let mut s = String::with_capacity(lhs.len() + rhs.len());
+ s.push_str(lhs);
+ *self = Cow::Owned(s);
+ }
+ self.to_mut().push_str(&rhs);
+ }
+ }
+}
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
new file mode 100644
index 000000000000..f753189c6830
--- /dev/null
+++ b/rust/alloc/boxed.rs
@@ -0,0 +1,2005 @@
+//! A pointer type for heap allocation.
+//!
+//! [`Box<T>`], casually referred to as a 'box', provides the simplest form of
+//! heap allocation in Rust. Boxes provide ownership for this allocation, and
+//! drop their contents when they go out of scope. Boxes also ensure that they
+//! never allocate more than `isize::MAX` bytes.
+//!
+//! # Examples
+//!
+//! Move a value from the stack to the heap by creating a [`Box`]:
+//!
+//! ```
+//! let val: u8 = 5;
+//! let boxed: Box<u8> = Box::new(val);
+//! ```
+//!
+//! Move a value from a [`Box`] back to the stack by [dereferencing]:
+//!
+//! ```
+//! let boxed: Box<u8> = Box::new(5);
+//! let val: u8 = *boxed;
+//! ```
+//!
+//! Creating a recursive data structure:
+//!
+//! ```
+//! #[derive(Debug)]
+//! enum List<T> {
+//! Cons(T, Box<List<T>>),
+//! Nil,
+//! }
+//!
+//! let list: List<i32> = List::Cons(1, Box::new(List::Cons(2, Box::new(List::Nil))));
+//! println!("{:?}", list);
+//! ```
+//!
+//! This will print `Cons(1, Cons(2, Nil))`.
+//!
+//! Recursive structures must be boxed, because if the definition of `Cons`
+//! looked like this:
+//!
+//! ```compile_fail,E0072
+//! # enum List<T> {
+//! Cons(T, List<T>),
+//! # }
+//! ```
+//!
+//! It wouldn't work. This is because the size of a `List` depends on how many
+//! elements are in the list, and so we don't know how much memory to allocate
+//! for a `Cons`. By introducing a [`Box<T>`], which has a defined size, we know how
+//! big `Cons` needs to be.
+//!
+//! # Memory layout
+//!
+//! For non-zero-sized values, a [`Box`] will use the [`Global`] allocator for
+//! its allocation. It is valid to convert both ways between a [`Box`] and a
+//! raw pointer allocated with the [`Global`] allocator, given that the
+//! [`Layout`] used with the allocator is correct for the type. More precisely,
+//! a `value: *mut T` that has been allocated with the [`Global`] allocator
+//! with `Layout::for_value(&*value)` may be converted into a box using
+//! [`Box::<T>::from_raw(value)`]. Conversely, the memory backing a `value: *mut
+//! T` obtained from [`Box::<T>::into_raw`] may be deallocated using the
+//! [`Global`] allocator with [`Layout::for_value(&*value)`].
+//!
+//! For zero-sized values, the `Box` pointer still has to be [valid] for reads
+//! and writes and sufficiently aligned. In particular, casting any aligned
+//! non-zero integer literal to a raw pointer produces a valid pointer, but a
+//! pointer pointing into previously allocated memory that since got freed is
+//! not valid. The recommended way to build a Box to a ZST if `Box::new` cannot
+//! be used is to use [`ptr::NonNull::dangling`].
+//!
+//! So long as `T: Sized`, a `Box<T>` is guaranteed to be represented
+//! as a single pointer and is also ABI-compatible with C pointers
+//! (i.e. the C type `T*`). This means that if you have extern "C"
+//! Rust functions that will be called from C, you can define those
+//! Rust functions using `Box<T>` types, and use `T*` as corresponding
+//! type on the C side. As an example, consider this C header which
+//! declares functions that create and destroy some kind of `Foo`
+//! value:
+//!
+//! ```c
+//! /* C header */
+//!
+//! /* Returns ownership to the caller */
+//! struct Foo* foo_new(void);
+//!
+//! /* Takes ownership from the caller; no-op when invoked with null */
+//! void foo_delete(struct Foo*);
+//! ```
+//!
+//! These two functions might be implemented in Rust as follows. Here, the
+//! `struct Foo*` type from C is translated to `Box<Foo>`, which captures
+//! the ownership constraints. Note also that the nullable argument to
+//! `foo_delete` is represented in Rust as `Option<Box<Foo>>`, since `Box<Foo>`
+//! cannot be null.
+//!
+//! ```
+//! #[repr(C)]
+//! pub struct Foo;
+//!
+//! #[no_mangle]
+//! pub extern "C" fn foo_new() -> Box<Foo> {
+//! Box::new(Foo)
+//! }
+//!
+//! #[no_mangle]
+//! pub extern "C" fn foo_delete(_: Option<Box<Foo>>) {}
+//! ```
+//!
+//! Even though `Box<T>` has the same representation and C ABI as a C pointer,
+//! this does not mean that you can convert an arbitrary `T*` into a `Box<T>`
+//! and expect things to work. `Box<T>` values will always be fully aligned,
+//! non-null pointers. Moreover, the destructor for `Box<T>` will attempt to
+//! free the value with the global allocator. In general, the best practice
+//! is to only use `Box<T>` for pointers that originated from the global
+//! allocator.
+//!
+//! **Important.** At least at present, you should avoid using
+//! `Box<T>` types for functions that are defined in C but invoked
+//! from Rust. In those cases, you should directly mirror the C types
+//! as closely as possible. Using types like `Box<T>` where the C
+//! definition is just using `T*` can lead to undefined behavior, as
+//! described in [rust-lang/unsafe-code-guidelines#198][ucg#198].
+//!
+//! [ucg#198]: https://github.com/rust-lang/unsafe-code-guidelines/issues/198
+//! [dereferencing]: core::ops::Deref
+//! [`Box::<T>::from_raw(value)`]: Box::from_raw
+//! [`Global`]: crate::alloc::Global
+//! [`Layout`]: crate::alloc::Layout
+//! [`Layout::for_value(&*value)`]: crate::alloc::Layout::for_value
+//! [valid]: ptr#safety
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use core::any::Any;
+use core::async_iter::AsyncIterator;
+use core::borrow;
+use core::cmp::Ordering;
+use core::convert::{From, TryFrom};
+use core::fmt;
+use core::future::Future;
+use core::hash::{Hash, Hasher};
+#[cfg(not(no_global_oom_handling))]
+use core::iter::FromIterator;
+use core::iter::{FusedIterator, Iterator};
+use core::marker::{Unpin, Unsize};
+use core::mem;
+use core::ops::{
+ CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
+};
+use core::pin::Pin;
+use core::ptr::{self, Unique};
+use core::task::{Context, Poll};
+
+#[cfg(not(no_global_oom_handling))]
+use crate::alloc::{handle_alloc_error, WriteCloneIntoRaw};
+use crate::alloc::{AllocError, Allocator, Global, Layout};
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::Cow;
+use crate::raw_vec::RawVec;
+#[cfg(not(no_global_oom_handling))]
+use crate::str::from_boxed_utf8_unchecked;
+#[cfg(not(no_global_oom_handling))]
+use crate::vec::Vec;
+
+/// A pointer type for heap allocation.
+///
+/// See the [module-level documentation](../../std/boxed/index.html) for more.
+#[lang = "owned_box"]
+#[fundamental]
+#[stable(feature = "rust1", since = "1.0.0")]
+// The declaration of the `Box` struct must be kept in sync with the
+// `alloc::alloc::box_free` function or ICEs will happen. See the comment
+// on `box_free` for more details.
+pub struct Box<
+ T: ?Sized,
+ #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+>(Unique<T>, A);
+
+impl<T> Box<T> {
+ /// Allocates memory on the heap and then places `x` into it.
+ ///
+ /// This doesn't actually allocate if `T` is zero-sized.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let five = Box::new(5);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline(always)]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
+ pub fn new(x: T) -> Self {
+ box x
+ }
+
+ /// Constructs a new box with uninitialized contents.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let mut five = Box::<u32>::new_uninit();
+ ///
+ /// let five = unsafe {
+ /// // Deferred initialization:
+ /// five.as_mut_ptr().write(5);
+ ///
+ /// five.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*five, 5)
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ #[inline]
+ pub fn new_uninit() -> Box<mem::MaybeUninit<T>> {
+ Self::new_uninit_in(Global)
+ }
+
+ /// Constructs a new `Box` with uninitialized contents, with the memory
+ /// being filled with `0` bytes.
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let zero = Box::<u32>::new_zeroed();
+ /// let zero = unsafe { zero.assume_init() };
+ ///
+ /// assert_eq!(*zero, 0)
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ pub fn new_zeroed() -> Box<mem::MaybeUninit<T>> {
+ Self::new_zeroed_in(Global)
+ }
+
+ /// Constructs a new `Pin<Box<T>>`. If `T` does not implement `Unpin`, then
+ /// `x` will be pinned in memory and unable to be moved.
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "pin", since = "1.33.0")]
+ #[must_use]
+ #[inline(always)]
+ pub fn pin(x: T) -> Pin<Box<T>> {
+ (box x).into()
+ }
+
+ /// Allocates memory on the heap then places `x` into it,
+ /// returning an error if the allocation fails
+ ///
+ /// This doesn't actually allocate if `T` is zero-sized.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// let five = Box::try_new(5)?;
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn try_new(x: T) -> Result<Self, AllocError> {
+ Self::try_new_in(x, Global)
+ }
+
+ /// Constructs a new box with uninitialized contents on the heap,
+ /// returning an error if the allocation fails
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// let mut five = Box::<u32>::try_new_uninit()?;
+ ///
+ /// let five = unsafe {
+ /// // Deferred initialization:
+ /// five.as_mut_ptr().write(5);
+ ///
+ /// five.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*five, 5);
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[inline]
+ pub fn try_new_uninit() -> Result<Box<mem::MaybeUninit<T>>, AllocError> {
+ Box::try_new_uninit_in(Global)
+ }
+
+ /// Constructs a new `Box` with uninitialized contents, with the memory
+ /// being filled with `0` bytes on the heap
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// let zero = Box::<u32>::try_new_zeroed()?;
+ /// let zero = unsafe { zero.assume_init() };
+ ///
+ /// assert_eq!(*zero, 0);
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[inline]
+ pub fn try_new_zeroed() -> Result<Box<mem::MaybeUninit<T>>, AllocError> {
+ Box::try_new_zeroed_in(Global)
+ }
+}
+
+impl<T, A: Allocator> Box<T, A> {
+ /// Allocates memory in the given allocator then places `x` into it.
+ ///
+ /// This doesn't actually allocate if `T` is zero-sized.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let five = Box::new_in(5, System);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[must_use]
+ #[inline]
+ pub const fn new_in(x: T, alloc: A) -> Self
+ where
+ A: ~const Allocator + ~const Drop,
+ {
+ let mut boxed = Self::new_uninit_in(alloc);
+ unsafe {
+ boxed.as_mut_ptr().write(x);
+ boxed.assume_init()
+ }
+ }
+
+ /// Allocates memory in the given allocator then places `x` into it,
+ /// returning an error if the allocation fails
+ ///
+ /// This doesn't actually allocate if `T` is zero-sized.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let five = Box::try_new_in(5, System)?;
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
+ where
+ T: ~const Drop,
+ A: ~const Allocator + ~const Drop,
+ {
+ let mut boxed = Self::try_new_uninit_in(alloc)?;
+ unsafe {
+ boxed.as_mut_ptr().write(x);
+ Ok(boxed.assume_init())
+ }
+ }
+
+ /// Constructs a new box with uninitialized contents in the provided allocator.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let mut five = Box::<u32, _>::new_uninit_in(System);
+ ///
+ /// let five = unsafe {
+ /// // Deferred initialization:
+ /// five.as_mut_ptr().write(5);
+ ///
+ /// five.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*five, 5)
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ pub const fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+ where
+ A: ~const Allocator + ~const Drop,
+ {
+ let layout = Layout::new::<mem::MaybeUninit<T>>();
+ // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
+ // That would make code size bigger.
+ match Box::try_new_uninit_in(alloc) {
+ Ok(m) => m,
+ Err(_) => handle_alloc_error(layout),
+ }
+ }
+
+ /// Constructs a new box with uninitialized contents in the provided allocator,
+ /// returning an error if the allocation fails
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let mut five = Box::<u32, _>::try_new_uninit_in(System)?;
+ ///
+ /// let five = unsafe {
+ /// // Deferred initialization:
+ /// five.as_mut_ptr().write(5);
+ ///
+ /// five.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*five, 5);
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ pub const fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+ where
+ A: ~const Allocator + ~const Drop,
+ {
+ let layout = Layout::new::<mem::MaybeUninit<T>>();
+ let ptr = alloc.allocate(layout)?.cast();
+ unsafe { Ok(Box::from_raw_in(ptr.as_ptr(), alloc)) }
+ }
+
+ /// Constructs a new `Box` with uninitialized contents, with the memory
+ /// being filled with `0` bytes in the provided allocator.
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let zero = Box::<u32, _>::new_zeroed_in(System);
+ /// let zero = unsafe { zero.assume_init() };
+ ///
+ /// assert_eq!(*zero, 0)
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[cfg(not(no_global_oom_handling))]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ pub const fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+ where
+ A: ~const Allocator + ~const Drop,
+ {
+ let layout = Layout::new::<mem::MaybeUninit<T>>();
+ // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
+ // That would make code size bigger.
+ match Box::try_new_zeroed_in(alloc) {
+ Ok(m) => m,
+ Err(_) => handle_alloc_error(layout),
+ }
+ }
+
+ /// Constructs a new `Box` with uninitialized contents, with the memory
+ /// being filled with `0` bytes in the provided allocator,
+ /// returning an error if the allocation fails,
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let zero = Box::<u32, _>::try_new_zeroed_in(System)?;
+ /// let zero = unsafe { zero.assume_init() };
+ ///
+ /// assert_eq!(*zero, 0);
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ pub const fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+ where
+ A: ~const Allocator + ~const Drop,
+ {
+ let layout = Layout::new::<mem::MaybeUninit<T>>();
+ let ptr = alloc.allocate_zeroed(layout)?.cast();
+ unsafe { Ok(Box::from_raw_in(ptr.as_ptr(), alloc)) }
+ }
+
+ /// Constructs a new `Pin<Box<T, A>>`. If `T` does not implement `Unpin`, then
+ /// `x` will be pinned in memory and unable to be moved.
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[must_use]
+ #[inline(always)]
+ pub const fn pin_in(x: T, alloc: A) -> Pin<Self>
+ where
+ A: 'static + ~const Allocator + ~const Drop,
+ {
+ Self::into_pin(Self::new_in(x, alloc))
+ }
+
+ /// Converts a `Box<T>` into a `Box<[T]>`
+ ///
+ /// This conversion does not allocate on the heap and happens in place.
+ #[unstable(feature = "box_into_boxed_slice", issue = "71582")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ pub const fn into_boxed_slice(boxed: Self) -> Box<[T], A> {
+ let (raw, alloc) = Box::into_raw_with_allocator(boxed);
+ unsafe { Box::from_raw_in(raw as *mut [T; 1], alloc) }
+ }
+
+ /// Consumes the `Box`, returning the wrapped value.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(box_into_inner)]
+ ///
+ /// let c = Box::new(5);
+ ///
+ /// assert_eq!(Box::into_inner(c), 5);
+ /// ```
+ #[unstable(feature = "box_into_inner", issue = "80437")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const fn into_inner(boxed: Self) -> T
+ where
+ Self: ~const Drop,
+ {
+ *boxed
+ }
+}
+
+impl<T> Box<[T]> {
+ /// Constructs a new boxed slice with uninitialized contents.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let mut values = Box::<[u32]>::new_uninit_slice(3);
+ ///
+ /// let values = unsafe {
+ /// // Deferred initialization:
+ /// values[0].as_mut_ptr().write(1);
+ /// values[1].as_mut_ptr().write(2);
+ /// values[2].as_mut_ptr().write(3);
+ ///
+ /// values.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*values, [1, 2, 3])
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ pub fn new_uninit_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
+ unsafe { RawVec::with_capacity(len).into_box(len) }
+ }
+
+ /// Constructs a new boxed slice with uninitialized contents, with the memory
+ /// being filled with `0` bytes.
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let values = Box::<[u32]>::new_zeroed_slice(3);
+ /// let values = unsafe { values.assume_init() };
+ ///
+ /// assert_eq!(*values, [0, 0, 0])
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ pub fn new_zeroed_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
+ unsafe { RawVec::with_capacity_zeroed(len).into_box(len) }
+ }
+
+ /// Constructs a new boxed slice with uninitialized contents. Returns an error if
+ /// the allocation fails
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// let mut values = Box::<[u32]>::try_new_uninit_slice(3)?;
+ /// let values = unsafe {
+ /// // Deferred initialization:
+ /// values[0].as_mut_ptr().write(1);
+ /// values[1].as_mut_ptr().write(2);
+ /// values[2].as_mut_ptr().write(3);
+ /// values.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*values, [1, 2, 3]);
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn try_new_uninit_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, AllocError> {
+ unsafe {
+ let layout = match Layout::array::<mem::MaybeUninit<T>>(len) {
+ Ok(l) => l,
+ Err(_) => return Err(AllocError),
+ };
+ let ptr = Global.allocate(layout)?;
+ Ok(RawVec::from_raw_parts_in(ptr.as_mut_ptr() as *mut _, len, Global).into_box(len))
+ }
+ }
+
+ /// Constructs a new boxed slice with uninitialized contents, with the memory
+ /// being filled with `0` bytes. Returns an error if the allocation fails
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// let values = Box::<[u32]>::try_new_zeroed_slice(3)?;
+ /// let values = unsafe { values.assume_init() };
+ ///
+ /// assert_eq!(*values, [0, 0, 0]);
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn try_new_zeroed_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, AllocError> {
+ unsafe {
+ let layout = match Layout::array::<mem::MaybeUninit<T>>(len) {
+ Ok(l) => l,
+ Err(_) => return Err(AllocError),
+ };
+ let ptr = Global.allocate_zeroed(layout)?;
+ Ok(RawVec::from_raw_parts_in(ptr.as_mut_ptr() as *mut _, len, Global).into_box(len))
+ }
+ }
+}
+
+impl<T, A: Allocator> Box<[T], A> {
+ /// Constructs a new boxed slice with uninitialized contents in the provided allocator.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System);
+ ///
+ /// let values = unsafe {
+ /// // Deferred initialization:
+ /// values[0].as_mut_ptr().write(1);
+ /// values[1].as_mut_ptr().write(2);
+ /// values[2].as_mut_ptr().write(3);
+ ///
+ /// values.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*values, [1, 2, 3])
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[mem::MaybeUninit<T>], A> {
+ unsafe { RawVec::with_capacity_in(len, alloc).into_box(len) }
+ }
+
+ /// Constructs a new boxed slice with uninitialized contents in the provided allocator,
+ /// with the memory being filled with `0` bytes.
+ ///
+ /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+ /// of this method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, new_uninit)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let values = Box::<[u32], _>::new_zeroed_slice_in(3, System);
+ /// let values = unsafe { values.assume_init() };
+ ///
+ /// assert_eq!(*values, [0, 0, 0])
+ /// ```
+ ///
+ /// [zeroed]: mem::MaybeUninit::zeroed
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "new_uninit", issue = "63291")]
+ #[must_use]
+ pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[mem::MaybeUninit<T>], A> {
+ unsafe { RawVec::with_capacity_zeroed_in(len, alloc).into_box(len) }
+ }
+}
+
+impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
+ /// Converts to `Box<T, A>`.
+ ///
+ /// # Safety
+ ///
+ /// As with [`MaybeUninit::assume_init`],
+ /// it is up to the caller to guarantee that the value
+ /// really is in an initialized state.
+ /// Calling this when the content is not yet fully initialized
+ /// causes immediate undefined behavior.
+ ///
+ /// [`MaybeUninit::assume_init`]: mem::MaybeUninit::assume_init
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let mut five = Box::<u32>::new_uninit();
+ ///
+ /// let five: Box<u32> = unsafe {
+ /// // Deferred initialization:
+ /// five.as_mut_ptr().write(5);
+ ///
+ /// five.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*five, 5)
+ /// ```
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const unsafe fn assume_init(self) -> Box<T, A> {
+ let (raw, alloc) = Box::into_raw_with_allocator(self);
+ unsafe { Box::from_raw_in(raw as *mut T, alloc) }
+ }
+
+ /// Writes the value and converts to `Box<T, A>`.
+ ///
+ /// This method converts the box similarly to [`Box::assume_init`] but
+ /// writes `value` into it before conversion thus guaranteeing safety.
+ /// In some scenarios use of this method may improve performance because
+ /// the compiler may be able to optimize copying from stack.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let big_box = Box::<[usize; 1024]>::new_uninit();
+ ///
+ /// let mut array = [0; 1024];
+ /// for (i, place) in array.iter_mut().enumerate() {
+ /// *place = i;
+ /// }
+ ///
+ /// // The optimizer may be able to elide this copy, so previous code writes
+ /// // to heap directly.
+ /// let big_box = Box::write(big_box, array);
+ ///
+ /// for (i, x) in big_box.iter().enumerate() {
+ /// assert_eq!(*x, i);
+ /// }
+ /// ```
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const fn write(mut boxed: Self, value: T) -> Box<T, A> {
+ unsafe {
+ (*boxed).write(value);
+ boxed.assume_init()
+ }
+ }
+}
+
+impl<T, A: Allocator> Box<[mem::MaybeUninit<T>], A> {
+ /// Converts to `Box<[T], A>`.
+ ///
+ /// # Safety
+ ///
+ /// As with [`MaybeUninit::assume_init`],
+ /// it is up to the caller to guarantee that the values
+ /// really are in an initialized state.
+ /// Calling this when the content is not yet fully initialized
+ /// causes immediate undefined behavior.
+ ///
+ /// [`MaybeUninit::assume_init`]: mem::MaybeUninit::assume_init
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(new_uninit)]
+ ///
+ /// let mut values = Box::<[u32]>::new_uninit_slice(3);
+ ///
+ /// let values = unsafe {
+ /// // Deferred initialization:
+ /// values[0].as_mut_ptr().write(1);
+ /// values[1].as_mut_ptr().write(2);
+ /// values[2].as_mut_ptr().write(3);
+ ///
+ /// values.assume_init()
+ /// };
+ ///
+ /// assert_eq!(*values, [1, 2, 3])
+ /// ```
+ #[unstable(feature = "new_uninit", issue = "63291")]
+ #[inline]
+ pub unsafe fn assume_init(self) -> Box<[T], A> {
+ let (raw, alloc) = Box::into_raw_with_allocator(self);
+ unsafe { Box::from_raw_in(raw as *mut [T], alloc) }
+ }
+}
+
+impl<T: ?Sized> Box<T> {
+ /// Constructs a box from a raw pointer.
+ ///
+ /// After calling this function, the raw pointer is owned by the
+ /// resulting `Box`. Specifically, the `Box` destructor will call
+ /// the destructor of `T` and free the allocated memory. For this
+ /// to be safe, the memory must have been allocated in accordance
+ /// with the [memory layout] used by `Box` .
+ ///
+ /// # Safety
+ ///
+ /// This function is unsafe because improper use may lead to
+ /// memory problems. For example, a double-free may occur if the
+ /// function is called twice on the same raw pointer.
+ ///
+ /// The safety conditions are described in the [memory layout] section.
+ ///
+ /// # Examples
+ ///
+ /// Recreate a `Box` which was previously converted to a raw pointer
+ /// using [`Box::into_raw`]:
+ /// ```
+ /// let x = Box::new(5);
+ /// let ptr = Box::into_raw(x);
+ /// let x = unsafe { Box::from_raw(ptr) };
+ /// ```
+ /// Manually create a `Box` from scratch by using the global allocator:
+ /// ```
+ /// use std::alloc::{alloc, Layout};
+ ///
+ /// unsafe {
+ /// let ptr = alloc(Layout::new::<i32>()) as *mut i32;
+ /// // In general .write is required to avoid attempting to destruct
+ /// // the (uninitialized) previous contents of `ptr`, though for this
+ /// // simple example `*ptr = 5` would have worked as well.
+ /// ptr.write(5);
+ /// let x = Box::from_raw(ptr);
+ /// }
+ /// ```
+ ///
+ /// [memory layout]: self#memory-layout
+ /// [`Layout`]: crate::Layout
+ #[stable(feature = "box_raw", since = "1.4.0")]
+ #[inline]
+ pub unsafe fn from_raw(raw: *mut T) -> Self {
+ unsafe { Self::from_raw_in(raw, Global) }
+ }
+}
+
+impl<T: ?Sized, A: Allocator> Box<T, A> {
+ /// Constructs a box from a raw pointer in the given allocator.
+ ///
+ /// After calling this function, the raw pointer is owned by the
+ /// resulting `Box`. Specifically, the `Box` destructor will call
+ /// the destructor of `T` and free the allocated memory. For this
+ /// to be safe, the memory must have been allocated in accordance
+ /// with the [memory layout] used by `Box` .
+ ///
+ /// # Safety
+ ///
+ /// This function is unsafe because improper use may lead to
+ /// memory problems. For example, a double-free may occur if the
+ /// function is called twice on the same raw pointer.
+ ///
+ ///
+ /// # Examples
+ ///
+ /// Recreate a `Box` which was previously converted to a raw pointer
+ /// using [`Box::into_raw_with_allocator`]:
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let x = Box::new_in(5, System);
+ /// let (ptr, alloc) = Box::into_raw_with_allocator(x);
+ /// let x = unsafe { Box::from_raw_in(ptr, alloc) };
+ /// ```
+ /// Manually create a `Box` from scratch by using the system allocator:
+ /// ```
+ /// #![feature(allocator_api, slice_ptr_get)]
+ ///
+ /// use std::alloc::{Allocator, Layout, System};
+ ///
+ /// unsafe {
+ /// let ptr = System.allocate(Layout::new::<i32>())?.as_mut_ptr() as *mut i32;
+ /// // In general .write is required to avoid attempting to destruct
+ /// // the (uninitialized) previous contents of `ptr`, though for this
+ /// // simple example `*ptr = 5` would have worked as well.
+ /// ptr.write(5);
+ /// let x = Box::from_raw_in(ptr, System);
+ /// }
+ /// # Ok::<(), std::alloc::AllocError>(())
+ /// ```
+ ///
+ /// [memory layout]: self#memory-layout
+ /// [`Layout`]: crate::Layout
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Self {
+ Box(unsafe { Unique::new_unchecked(raw) }, alloc)
+ }
+
+ /// Consumes the `Box`, returning a wrapped raw pointer.
+ ///
+ /// The pointer will be properly aligned and non-null.
+ ///
+ /// After calling this function, the caller is responsible for the
+ /// memory previously managed by the `Box`. In particular, the
+ /// caller should properly destroy `T` and release the memory, taking
+ /// into account the [memory layout] used by `Box`. The easiest way to
+ /// do this is to convert the raw pointer back into a `Box` with the
+ /// [`Box::from_raw`] function, allowing the `Box` destructor to perform
+ /// the cleanup.
+ ///
+ /// Note: this is an associated function, which means that you have
+ /// to call it as `Box::into_raw(b)` instead of `b.into_raw()`. This
+ /// is so that there is no conflict with a method on the inner type.
+ ///
+ /// # Examples
+ /// Converting the raw pointer back into a `Box` with [`Box::from_raw`]
+ /// for automatic cleanup:
+ /// ```
+ /// let x = Box::new(String::from("Hello"));
+ /// let ptr = Box::into_raw(x);
+ /// let x = unsafe { Box::from_raw(ptr) };
+ /// ```
+ /// Manual cleanup by explicitly running the destructor and deallocating
+ /// the memory:
+ /// ```
+ /// use std::alloc::{dealloc, Layout};
+ /// use std::ptr;
+ ///
+ /// let x = Box::new(String::from("Hello"));
+ /// let p = Box::into_raw(x);
+ /// unsafe {
+ /// ptr::drop_in_place(p);
+ /// dealloc(p as *mut u8, Layout::new::<String>());
+ /// }
+ /// ```
+ ///
+ /// [memory layout]: self#memory-layout
+ #[stable(feature = "box_raw", since = "1.4.0")]
+ #[inline]
+ pub fn into_raw(b: Self) -> *mut T {
+ Self::into_raw_with_allocator(b).0
+ }
+
+ /// Consumes the `Box`, returning a wrapped raw pointer and the allocator.
+ ///
+ /// The pointer will be properly aligned and non-null.
+ ///
+ /// After calling this function, the caller is responsible for the
+ /// memory previously managed by the `Box`. In particular, the
+ /// caller should properly destroy `T` and release the memory, taking
+ /// into account the [memory layout] used by `Box`. The easiest way to
+ /// do this is to convert the raw pointer back into a `Box` with the
+ /// [`Box::from_raw_in`] function, allowing the `Box` destructor to perform
+ /// the cleanup.
+ ///
+ /// Note: this is an associated function, which means that you have
+ /// to call it as `Box::into_raw_with_allocator(b)` instead of `b.into_raw_with_allocator()`. This
+ /// is so that there is no conflict with a method on the inner type.
+ ///
+ /// # Examples
+ /// Converting the raw pointer back into a `Box` with [`Box::from_raw_in`]
+ /// for automatic cleanup:
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let x = Box::new_in(String::from("Hello"), System);
+ /// let (ptr, alloc) = Box::into_raw_with_allocator(x);
+ /// let x = unsafe { Box::from_raw_in(ptr, alloc) };
+ /// ```
+ /// Manual cleanup by explicitly running the destructor and deallocating
+ /// the memory:
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::{Allocator, Layout, System};
+ /// use std::ptr::{self, NonNull};
+ ///
+ /// let x = Box::new_in(String::from("Hello"), System);
+ /// let (ptr, alloc) = Box::into_raw_with_allocator(x);
+ /// unsafe {
+ /// ptr::drop_in_place(ptr);
+ /// let non_null = NonNull::new_unchecked(ptr);
+ /// alloc.deallocate(non_null.cast(), Layout::new::<String>());
+ /// }
+ /// ```
+ ///
+ /// [memory layout]: self#memory-layout
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
+ let (leaked, alloc) = Box::into_unique(b);
+ (leaked.as_ptr(), alloc)
+ }
+
+ #[unstable(
+ feature = "ptr_internals",
+ issue = "none",
+ reason = "use `Box::leak(b).into()` or `Unique::from(Box::leak(b))` instead"
+ )]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ #[doc(hidden)]
+ pub const fn into_unique(b: Self) -> (Unique<T>, A) {
+ // Box is recognized as a "unique pointer" by Stacked Borrows, but internally it is a
+ // raw pointer for the type system. Turning it directly into a raw pointer would not be
+ // recognized as "releasing" the unique pointer to permit aliased raw accesses,
+ // so all raw pointer methods have to go through `Box::leak`. Turning *that* to a raw pointer
+ // behaves correctly.
+ let alloc = unsafe { ptr::read(&b.1) };
+ (Unique::from(Box::leak(b)), alloc)
+ }
+
+ /// Returns a reference to the underlying allocator.
+ ///
+ /// Note: this is an associated function, which means that you have
+ /// to call it as `Box::allocator(&b)` instead of `b.allocator()`. This
+ /// is so that there is no conflict with a method on the inner type.
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const fn allocator(b: &Self) -> &A {
+ &b.1
+ }
+
+ /// Consumes and leaks the `Box`, returning a mutable reference,
+ /// `&'a mut T`. Note that the type `T` must outlive the chosen lifetime
+ /// `'a`. If the type has only static references, or none at all, then this
+ /// may be chosen to be `'static`.
+ ///
+ /// This function is mainly useful for data that lives for the remainder of
+ /// the program's life. Dropping the returned reference will cause a memory
+ /// leak. If this is not acceptable, the reference should first be wrapped
+ /// with the [`Box::from_raw`] function producing a `Box`. This `Box` can
+ /// then be dropped which will properly destroy `T` and release the
+ /// allocated memory.
+ ///
+ /// Note: this is an associated function, which means that you have
+ /// to call it as `Box::leak(b)` instead of `b.leak()`. This
+ /// is so that there is no conflict with a method on the inner type.
+ ///
+ /// # Examples
+ ///
+ /// Simple usage:
+ ///
+ /// ```
+ /// let x = Box::new(41);
+ /// let static_ref: &'static mut usize = Box::leak(x);
+ /// *static_ref += 1;
+ /// assert_eq!(*static_ref, 42);
+ /// ```
+ ///
+ /// Unsized data:
+ ///
+ /// ```
+ /// let x = vec![1, 2, 3].into_boxed_slice();
+ /// let static_ref = Box::leak(x);
+ /// static_ref[0] = 4;
+ /// assert_eq!(*static_ref, [4, 2, 3]);
+ /// ```
+ #[stable(feature = "box_leak", since = "1.26.0")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ #[inline]
+ pub const fn leak<'a>(b: Self) -> &'a mut T
+ where
+ A: 'a,
+ {
+ unsafe { &mut *mem::ManuallyDrop::new(b).0.as_ptr() }
+ }
+
+ /// Converts a `Box<T>` into a `Pin<Box<T>>`
+ ///
+ /// This conversion does not allocate on the heap and happens in place.
+ ///
+ /// This is also available via [`From`].
+ #[unstable(feature = "box_into_pin", issue = "62370")]
+ #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+ pub const fn into_pin(boxed: Self) -> Pin<Self>
+ where
+ A: 'static,
+ {
+ // It's not possible to move or replace the insides of a `Pin<Box<T>>`
+ // when `T: !Unpin`, so it's safe to pin it directly without any
+ // additional requirements.
+ unsafe { Pin::new_unchecked(boxed) }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<#[may_dangle] T: ?Sized, A: Allocator> Drop for Box<T, A> {
+ fn drop(&mut self) {
+ // FIXME: Do nothing, drop is currently performed by compiler.
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Default> Default for Box<T> {
+ /// Creates a `Box<T>`, with the `Default` value for T.
+ fn default() -> Self {
+ box T::default()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Default for Box<[T]> {
+ fn default() -> Self {
+ Box::<[T; 0]>::new([])
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "default_box_extra", since = "1.17.0")]
+impl Default for Box<str> {
+ fn default() -> Self {
+ unsafe { from_boxed_utf8_unchecked(Default::default()) }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for Box<T, A> {
+ /// Returns a new box with a `clone()` of this box's contents.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let x = Box::new(5);
+ /// let y = x.clone();
+ ///
+ /// // The value is the same
+ /// assert_eq!(x, y);
+ ///
+ /// // But they are unique objects
+ /// assert_ne!(&*x as *const i32, &*y as *const i32);
+ /// ```
+ #[inline]
+ fn clone(&self) -> Self {
+ // Pre-allocate memory to allow writing the cloned value directly.
+ let mut boxed = Self::new_uninit_in(self.1.clone());
+ unsafe {
+ (**self).write_clone_into_raw(boxed.as_mut_ptr());
+ boxed.assume_init()
+ }
+ }
+
+ /// Copies `source`'s contents into `self` without creating a new allocation.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let x = Box::new(5);
+ /// let mut y = Box::new(10);
+ /// let yp: *const i32 = &*y;
+ ///
+ /// y.clone_from(&x);
+ ///
+ /// // The value is the same
+ /// assert_eq!(x, y);
+ ///
+ /// // And no allocation occurred
+ /// assert_eq!(yp, &*y);
+ /// ```
+ #[inline]
+ fn clone_from(&mut self, source: &Self) {
+ (**self).clone_from(&(**source));
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_slice_clone", since = "1.3.0")]
+impl Clone for Box<str> {
+ fn clone(&self) -> Self {
+ // this makes a copy of the data
+ let buf: Box<[u8]> = self.as_bytes().into();
+ unsafe { from_boxed_utf8_unchecked(buf) }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + PartialEq, A: Allocator> PartialEq for Box<T, A> {
+ #[inline]
+ fn eq(&self, other: &Self) -> bool {
+ PartialEq::eq(&**self, &**other)
+ }
+ #[inline]
+ fn ne(&self, other: &Self) -> bool {
+ PartialEq::ne(&**self, &**other)
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + PartialOrd, A: Allocator> PartialOrd for Box<T, A> {
+ #[inline]
+ fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+ PartialOrd::partial_cmp(&**self, &**other)
+ }
+ #[inline]
+ fn lt(&self, other: &Self) -> bool {
+ PartialOrd::lt(&**self, &**other)
+ }
+ #[inline]
+ fn le(&self, other: &Self) -> bool {
+ PartialOrd::le(&**self, &**other)
+ }
+ #[inline]
+ fn ge(&self, other: &Self) -> bool {
+ PartialOrd::ge(&**self, &**other)
+ }
+ #[inline]
+ fn gt(&self, other: &Self) -> bool {
+ PartialOrd::gt(&**self, &**other)
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + Ord, A: Allocator> Ord for Box<T, A> {
+ #[inline]
+ fn cmp(&self, other: &Self) -> Ordering {
+ Ord::cmp(&**self, &**other)
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + Eq, A: Allocator> Eq for Box<T, A> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + Hash, A: Allocator> Hash for Box<T, A> {
+ fn hash<H: Hasher>(&self, state: &mut H) {
+ (**self).hash(state);
+ }
+}
+
+#[stable(feature = "indirect_hasher_impl", since = "1.22.0")]
+impl<T: ?Sized + Hasher, A: Allocator> Hasher for Box<T, A> {
+ fn finish(&self) -> u64 {
+ (**self).finish()
+ }
+ fn write(&mut self, bytes: &[u8]) {
+ (**self).write(bytes)
+ }
+ fn write_u8(&mut self, i: u8) {
+ (**self).write_u8(i)
+ }
+ fn write_u16(&mut self, i: u16) {
+ (**self).write_u16(i)
+ }
+ fn write_u32(&mut self, i: u32) {
+ (**self).write_u32(i)
+ }
+ fn write_u64(&mut self, i: u64) {
+ (**self).write_u64(i)
+ }
+ fn write_u128(&mut self, i: u128) {
+ (**self).write_u128(i)
+ }
+ fn write_usize(&mut self, i: usize) {
+ (**self).write_usize(i)
+ }
+ fn write_i8(&mut self, i: i8) {
+ (**self).write_i8(i)
+ }
+ fn write_i16(&mut self, i: i16) {
+ (**self).write_i16(i)
+ }
+ fn write_i32(&mut self, i: i32) {
+ (**self).write_i32(i)
+ }
+ fn write_i64(&mut self, i: i64) {
+ (**self).write_i64(i)
+ }
+ fn write_i128(&mut self, i: i128) {
+ (**self).write_i128(i)
+ }
+ fn write_isize(&mut self, i: isize) {
+ (**self).write_isize(i)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_for_ptrs", since = "1.6.0")]
+impl<T> From<T> for Box<T> {
+ /// Converts a `T` into a `Box<T>`
+ ///
+ /// The conversion allocates on the heap and moves `t`
+ /// from the stack into it.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// let x = 5;
+ /// let boxed = Box::new(5);
+ ///
+ /// assert_eq!(Box::from(x), boxed);
+ /// ```
+ fn from(t: T) -> Self {
+ Box::new(t)
+ }
+}
+
+#[stable(feature = "pin", since = "1.33.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const From<Box<T, A>> for Pin<Box<T, A>>
+where
+ A: 'static,
+{
+ /// Converts a `Box<T>` into a `Pin<Box<T>>`
+ ///
+ /// This conversion does not allocate on the heap and happens in place.
+ fn from(boxed: Box<T, A>) -> Self {
+ Box::into_pin(boxed)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_slice", since = "1.17.0")]
+impl<T: Copy> From<&[T]> for Box<[T]> {
+ /// Converts a `&[T]` into a `Box<[T]>`
+ ///
+ /// This conversion allocates on the heap
+ /// and performs a copy of `slice`.
+ ///
+ /// # Examples
+ /// ```rust
+ /// // create a &[u8] which will be used to create a Box<[u8]>
+ /// let slice: &[u8] = &[104, 101, 108, 108, 111];
+ /// let boxed_slice: Box<[u8]> = Box::from(slice);
+ ///
+ /// println!("{:?}", boxed_slice);
+ /// ```
+ fn from(slice: &[T]) -> Box<[T]> {
+ let len = slice.len();
+ let buf = RawVec::with_capacity(len);
+ unsafe {
+ ptr::copy_nonoverlapping(slice.as_ptr(), buf.ptr(), len);
+ buf.into_box(slice.len()).assume_init()
+ }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_cow", since = "1.45.0")]
+impl<T: Copy> From<Cow<'_, [T]>> for Box<[T]> {
+ /// Converts a `Cow<'_, [T]>` into a `Box<[T]>`
+ ///
+ /// When `cow` is the `Cow::Borrowed` variant, this
+ /// conversion allocates on the heap and copies the
+ /// underlying slice. Otherwise, it will try to reuse the owned
+ /// `Vec`'s allocation.
+ #[inline]
+ fn from(cow: Cow<'_, [T]>) -> Box<[T]> {
+ match cow {
+ Cow::Borrowed(slice) => Box::from(slice),
+ Cow::Owned(slice) => Box::from(slice),
+ }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_slice", since = "1.17.0")]
+impl From<&str> for Box<str> {
+ /// Converts a `&str` into a `Box<str>`
+ ///
+ /// This conversion allocates on the heap
+ /// and performs a copy of `s`.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// let boxed: Box<str> = Box::from("hello");
+ /// println!("{}", boxed);
+ /// ```
+ #[inline]
+ fn from(s: &str) -> Box<str> {
+ unsafe { from_boxed_utf8_unchecked(Box::from(s.as_bytes())) }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_cow", since = "1.45.0")]
+impl From<Cow<'_, str>> for Box<str> {
+ /// Converts a `Cow<'_, str>` into a `Box<str>`
+ ///
+ /// When `cow` is the `Cow::Borrowed` variant, this
+ /// conversion allocates on the heap and copies the
+ /// underlying `str`. Otherwise, it will try to reuse the owned
+ /// `String`'s allocation.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// use std::borrow::Cow;
+ ///
+ /// let unboxed = Cow::Borrowed("hello");
+ /// let boxed: Box<str> = Box::from(unboxed);
+ /// println!("{}", boxed);
+ /// ```
+ ///
+ /// ```rust
+ /// # use std::borrow::Cow;
+ /// let unboxed = Cow::Owned("hello".to_string());
+ /// let boxed: Box<str> = Box::from(unboxed);
+ /// println!("{}", boxed);
+ /// ```
+ #[inline]
+ fn from(cow: Cow<'_, str>) -> Box<str> {
+ match cow {
+ Cow::Borrowed(s) => Box::from(s),
+ Cow::Owned(s) => Box::from(s),
+ }
+ }
+}
+
+#[stable(feature = "boxed_str_conv", since = "1.19.0")]
+impl<A: Allocator> From<Box<str, A>> for Box<[u8], A> {
+ /// Converts a `Box<str>` into a `Box<[u8]>`
+ ///
+ /// This conversion does not allocate on the heap and happens in place.
+ ///
+ /// # Examples
+ /// ```rust
+ /// // create a Box<str> which will be used to create a Box<[u8]>
+ /// let boxed: Box<str> = Box::from("hello");
+ /// let boxed_str: Box<[u8]> = Box::from(boxed);
+ ///
+ /// // create a &[u8] which will be used to create a Box<[u8]>
+ /// let slice: &[u8] = &[104, 101, 108, 108, 111];
+ /// let boxed_slice = Box::from(slice);
+ ///
+ /// assert_eq!(boxed_slice, boxed_str);
+ /// ```
+ #[inline]
+ fn from(s: Box<str, A>) -> Self {
+ let (raw, alloc) = Box::into_raw_with_allocator(s);
+ unsafe { Box::from_raw_in(raw as *mut [u8], alloc) }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_array", since = "1.45.0")]
+impl<T, const N: usize> From<[T; N]> for Box<[T]> {
+ /// Converts a `[T; N]` into a `Box<[T]>`
+ ///
+ /// This conversion moves the array to newly heap-allocated memory.
+ ///
+ /// # Examples
+ ///
+ /// ```rust
+ /// let boxed: Box<[u8]> = Box::from([4, 2]);
+ /// println!("{:?}", boxed);
+ /// ```
+ fn from(array: [T; N]) -> Box<[T]> {
+ box array
+ }
+}
+
+#[stable(feature = "boxed_slice_try_from", since = "1.43.0")]
+impl<T, const N: usize> TryFrom<Box<[T]>> for Box<[T; N]> {
+ type Error = Box<[T]>;
+
+ /// Attempts to convert a `Box<[T]>` into a `Box<[T; N]>`.
+ ///
+ /// The conversion occurs in-place and does not require a
+ /// new memory allocation.
+ ///
+ /// # Errors
+ ///
+ /// Returns the old `Box<[T]>` in the `Err` variant if
+ /// `boxed_slice.len()` does not equal `N`.
+ fn try_from(boxed_slice: Box<[T]>) -> Result<Self, Self::Error> {
+ if boxed_slice.len() == N {
+ Ok(unsafe { Box::from_raw(Box::into_raw(boxed_slice) as *mut [T; N]) })
+ } else {
+ Err(boxed_slice)
+ }
+ }
+}
+
+impl<A: Allocator> Box<dyn Any, A> {
+ /// Attempt to downcast the box to a concrete type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::any::Any;
+ ///
+ /// fn print_if_string(value: Box<dyn Any>) {
+ /// if let Ok(string) = value.downcast::<String>() {
+ /// println!("String ({}): {}", string.len(), string);
+ /// }
+ /// }
+ ///
+ /// let my_string = "Hello World".to_string();
+ /// print_if_string(Box::new(my_string));
+ /// print_if_string(Box::new(0i8));
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
+ if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
+ }
+
+ /// Downcasts the box to a concrete type.
+ ///
+ /// For a safe alternative see [`downcast`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let x: Box<dyn Any> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// assert_eq!(*x.downcast_unchecked::<usize>(), 1);
+ /// }
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// The contained value must be of type `T`. Calling this method
+ /// with the incorrect type is *undefined behavior*.
+ ///
+ /// [`downcast`]: Self::downcast
+ #[inline]
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
+ debug_assert!(self.is::<T>());
+ unsafe {
+ let (raw, alloc): (*mut dyn Any, _) = Box::into_raw_with_allocator(self);
+ Box::from_raw_in(raw as *mut T, alloc)
+ }
+ }
+}
+
+impl<A: Allocator> Box<dyn Any + Send, A> {
+ /// Attempt to downcast the box to a concrete type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::any::Any;
+ ///
+ /// fn print_if_string(value: Box<dyn Any + Send>) {
+ /// if let Ok(string) = value.downcast::<String>() {
+ /// println!("String ({}): {}", string.len(), string);
+ /// }
+ /// }
+ ///
+ /// let my_string = "Hello World".to_string();
+ /// print_if_string(Box::new(my_string));
+ /// print_if_string(Box::new(0i8));
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
+ if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
+ }
+
+ /// Downcasts the box to a concrete type.
+ ///
+ /// For a safe alternative see [`downcast`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let x: Box<dyn Any + Send> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// assert_eq!(*x.downcast_unchecked::<usize>(), 1);
+ /// }
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// The contained value must be of type `T`. Calling this method
+ /// with the incorrect type is *undefined behavior*.
+ ///
+ /// [`downcast`]: Self::downcast
+ #[inline]
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
+ debug_assert!(self.is::<T>());
+ unsafe {
+ let (raw, alloc): (*mut (dyn Any + Send), _) = Box::into_raw_with_allocator(self);
+ Box::from_raw_in(raw as *mut T, alloc)
+ }
+ }
+}
+
+impl<A: Allocator> Box<dyn Any + Send + Sync, A> {
+ /// Attempt to downcast the box to a concrete type.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::any::Any;
+ ///
+ /// fn print_if_string(value: Box<dyn Any + Send + Sync>) {
+ /// if let Ok(string) = value.downcast::<String>() {
+ /// println!("String ({}): {}", string.len(), string);
+ /// }
+ /// }
+ ///
+ /// let my_string = "Hello World".to_string();
+ /// print_if_string(Box::new(my_string));
+ /// print_if_string(Box::new(0i8));
+ /// ```
+ #[inline]
+ #[stable(feature = "box_send_sync_any_downcast", since = "1.51.0")]
+ pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
+ if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
+ }
+
+ /// Downcasts the box to a concrete type.
+ ///
+ /// For a safe alternative see [`downcast`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(downcast_unchecked)]
+ ///
+ /// use std::any::Any;
+ ///
+ /// let x: Box<dyn Any + Send + Sync> = Box::new(1_usize);
+ ///
+ /// unsafe {
+ /// assert_eq!(*x.downcast_unchecked::<usize>(), 1);
+ /// }
+ /// ```
+ ///
+ /// # Safety
+ ///
+ /// The contained value must be of type `T`. Calling this method
+ /// with the incorrect type is *undefined behavior*.
+ ///
+ /// [`downcast`]: Self::downcast
+ #[inline]
+ #[unstable(feature = "downcast_unchecked", issue = "90850")]
+ pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
+ debug_assert!(self.is::<T>());
+ unsafe {
+ let (raw, alloc): (*mut (dyn Any + Send + Sync), _) =
+ Box::into_raw_with_allocator(self);
+ Box::from_raw_in(raw as *mut T, alloc)
+ }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Display + ?Sized, A: Allocator> fmt::Display for Box<T, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Display::fmt(&**self, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Debug + ?Sized, A: Allocator> fmt::Debug for Box<T, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Debug::fmt(&**self, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized, A: Allocator> fmt::Pointer for Box<T, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ // It's not possible to extract the inner Uniq directly from the Box,
+ // instead we cast it to a *const which aliases the Unique
+ let ptr: *const T = &**self;
+ fmt::Pointer::fmt(&ptr, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const Deref for Box<T, A> {
+ type Target = T;
+
+ fn deref(&self) -> &T {
+ &**self
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const DerefMut for Box<T, A> {
+ fn deref_mut(&mut self) -> &mut T {
+ &mut **self
+ }
+}
+
+#[unstable(feature = "receiver_trait", issue = "none")]
+impl<T: ?Sized, A: Allocator> Receiver for Box<T, A> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> {
+ type Item = I::Item;
+ fn next(&mut self) -> Option<I::Item> {
+ (**self).next()
+ }
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (**self).size_hint()
+ }
+ fn nth(&mut self, n: usize) -> Option<I::Item> {
+ (**self).nth(n)
+ }
+ fn last(self) -> Option<I::Item> {
+ BoxIter::last(self)
+ }
+}
+
+trait BoxIter {
+ type Item;
+ fn last(self) -> Option<Self::Item>;
+}
+
+impl<I: Iterator + ?Sized, A: Allocator> BoxIter for Box<I, A> {
+ type Item = I::Item;
+ default fn last(self) -> Option<I::Item> {
+ #[inline]
+ fn some<T>(_: Option<T>, x: T) -> Option<T> {
+ Some(x)
+ }
+
+ self.fold(None, some)
+ }
+}
+
+/// Specialization for sized `I`s that uses `I`s implementation of `last()`
+/// instead of the default.
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, A: Allocator> BoxIter for Box<I, A> {
+ fn last(self) -> Option<I::Item> {
+ (*self).last()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: DoubleEndedIterator + ?Sized, A: Allocator> DoubleEndedIterator for Box<I, A> {
+ fn next_back(&mut self) -> Option<I::Item> {
+ (**self).next_back()
+ }
+ fn nth_back(&mut self, n: usize) -> Option<I::Item> {
+ (**self).nth_back(n)
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: ExactSizeIterator + ?Sized, A: Allocator> ExactSizeIterator for Box<I, A> {
+ fn len(&self) -> usize {
+ (**self).len()
+ }
+ fn is_empty(&self) -> bool {
+ (**self).is_empty()
+ }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I: FusedIterator + ?Sized, A: Allocator> FusedIterator for Box<I, A> {}
+
+#[stable(feature = "boxed_closure_impls", since = "1.35.0")]
+impl<Args, F: FnOnce<Args> + ?Sized, A: Allocator> FnOnce<Args> for Box<F, A> {
+ type Output = <F as FnOnce<Args>>::Output;
+
+ extern "rust-call" fn call_once(self, args: Args) -> Self::Output {
+ <F as FnOnce<Args>>::call_once(*self, args)
+ }
+}
+
+#[stable(feature = "boxed_closure_impls", since = "1.35.0")]
+impl<Args, F: FnMut<Args> + ?Sized, A: Allocator> FnMut<Args> for Box<F, A> {
+ extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output {
+ <F as FnMut<Args>>::call_mut(self, args)
+ }
+}
+
+#[stable(feature = "boxed_closure_impls", since = "1.35.0")]
+impl<Args, F: Fn<Args> + ?Sized, A: Allocator> Fn<Args> for Box<F, A> {
+ extern "rust-call" fn call(&self, args: Args) -> Self::Output {
+ <F as Fn<Args>>::call(self, args)
+ }
+}
+
+#[unstable(feature = "coerce_unsized", issue = "27732")]
+impl<T: ?Sized + Unsize<U>, U: ?Sized, A: Allocator> CoerceUnsized<Box<U, A>> for Box<T, A> {}
+
+#[unstable(feature = "dispatch_from_dyn", issue = "none")]
+impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U>> for Box<T, Global> {}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "boxed_slice_from_iter", since = "1.32.0")]
+impl<I> FromIterator<I> for Box<[I]> {
+ fn from_iter<T: IntoIterator<Item = I>>(iter: T) -> Self {
+ iter.into_iter().collect::<Vec<_>>().into_boxed_slice()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_slice_clone", since = "1.3.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for Box<[T], A> {
+ fn clone(&self) -> Self {
+ let alloc = Box::allocator(self).clone();
+ self.to_vec_in(alloc).into_boxed_slice()
+ }
+
+ fn clone_from(&mut self, other: &Self) {
+ if self.len() == other.len() {
+ self.clone_from_slice(&other);
+ } else {
+ *self = other.clone();
+ }
+ }
+}
+
+#[stable(feature = "box_borrow", since = "1.1.0")]
+impl<T: ?Sized, A: Allocator> borrow::Borrow<T> for Box<T, A> {
+ fn borrow(&self) -> &T {
+ &**self
+ }
+}
+
+#[stable(feature = "box_borrow", since = "1.1.0")]
+impl<T: ?Sized, A: Allocator> borrow::BorrowMut<T> for Box<T, A> {
+ fn borrow_mut(&mut self) -> &mut T {
+ &mut **self
+ }
+}
+
+#[stable(since = "1.5.0", feature = "smart_ptr_as_ref")]
+impl<T: ?Sized, A: Allocator> AsRef<T> for Box<T, A> {
+ fn as_ref(&self) -> &T {
+ &**self
+ }
+}
+
+#[stable(since = "1.5.0", feature = "smart_ptr_as_ref")]
+impl<T: ?Sized, A: Allocator> AsMut<T> for Box<T, A> {
+ fn as_mut(&mut self) -> &mut T {
+ &mut **self
+ }
+}
+
+/* Nota bene
+ *
+ * We could have chosen not to add this impl, and instead have written a
+ * function of Pin<Box<T>> to Pin<T>. Such a function would not be sound,
+ * because Box<T> implements Unpin even when T does not, as a result of
+ * this impl.
+ *
+ * We chose this API instead of the alternative for a few reasons:
+ * - Logically, it is helpful to understand pinning in regard to the
+ * memory region being pointed to. For this reason none of the
+ * standard library pointer types support projecting through a pin
+ * (Box<T> is the only pointer type in std for which this would be
+ * safe.)
+ * - It is in practice very useful to have Box<T> be unconditionally
+ * Unpin because of trait objects, for which the structural auto
+ * trait functionality does not apply (e.g., Box<dyn Foo> would
+ * otherwise not be Unpin).
+ *
+ * Another type with the same semantics as Box but only a conditional
+ * implementation of `Unpin` (where `T: Unpin`) would be valid/safe, and
+ * could have a method to project a Pin<T> from it.
+ */
+#[stable(feature = "pin", since = "1.33.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const Unpin for Box<T, A> where A: 'static {}
+
+#[unstable(feature = "generator_trait", issue = "43122")]
+impl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>
+where
+ A: 'static,
+{
+ type Yield = G::Yield;
+ type Return = G::Return;
+
+ fn resume(mut self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+ G::resume(Pin::new(&mut *self), arg)
+ }
+}
+
+#[unstable(feature = "generator_trait", issue = "43122")]
+impl<G: ?Sized + Generator<R>, R, A: Allocator> Generator<R> for Pin<Box<G, A>>
+where
+ A: 'static,
+{
+ type Yield = G::Yield;
+ type Return = G::Return;
+
+ fn resume(mut self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+ G::resume((*self).as_mut(), arg)
+ }
+}
+
+#[stable(feature = "futures_api", since = "1.36.0")]
+impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>
+where
+ A: 'static,
+{
+ type Output = F::Output;
+
+ fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+ F::poll(Pin::new(&mut *self), cx)
+ }
+}
+
+#[unstable(feature = "async_iterator", issue = "79024")]
+impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S> {
+ type Item = S::Item;
+
+ fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+ Pin::new(&mut **self).poll_next(cx)
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (**self).size_hint()
+ }
+}
diff --git a/rust/alloc/collections/mod.rs b/rust/alloc/collections/mod.rs
new file mode 100644
index 000000000000..628a5b155673
--- /dev/null
+++ b/rust/alloc/collections/mod.rs
@@ -0,0 +1,154 @@
+//! Collection types.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[cfg(not(no_global_oom_handling))]
+pub mod binary_heap;
+#[cfg(not(no_global_oom_handling))]
+mod btree;
+#[cfg(not(no_global_oom_handling))]
+pub mod linked_list;
+#[cfg(not(no_global_oom_handling))]
+pub mod vec_deque;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub mod btree_map {
+ //! An ordered map based on a B-Tree.
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub use super::btree::map::*;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub mod btree_set {
+ //! An ordered set based on a B-Tree.
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub use super::btree::set::*;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use binary_heap::BinaryHeap;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use btree_map::BTreeMap;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use btree_set::BTreeSet;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use linked_list::LinkedList;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use vec_deque::VecDeque;
+
+use crate::alloc::{Layout, LayoutError};
+use core::fmt::Display;
+
+/// The error type for `try_reserve` methods.
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[stable(feature = "try_reserve", since = "1.57.0")]
+pub struct TryReserveError {
+ kind: TryReserveErrorKind,
+}
+
+impl TryReserveError {
+ /// Details about the allocation that caused the error
+ #[inline]
+ #[must_use]
+ #[unstable(
+ feature = "try_reserve_kind",
+ reason = "Uncertain how much info should be exposed",
+ issue = "48043"
+ )]
+ pub fn kind(&self) -> TryReserveErrorKind {
+ self.kind.clone()
+ }
+}
+
+/// Details of the allocation that caused a `TryReserveError`
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[unstable(
+ feature = "try_reserve_kind",
+ reason = "Uncertain how much info should be exposed",
+ issue = "48043"
+)]
+pub enum TryReserveErrorKind {
+ /// Error due to the computed capacity exceeding the collection's maximum
+ /// (usually `isize::MAX` bytes).
+ CapacityOverflow,
+
+ /// The memory allocator returned an error
+ AllocError {
+ /// The layout of allocation request that failed
+ layout: Layout,
+
+ #[doc(hidden)]
+ #[unstable(
+ feature = "container_error_extra",
+ issue = "none",
+ reason = "\
+ Enable exposing the allocator’s custom error value \
+ if an associated type is added in the future: \
+ https://github.com/rust-lang/wg-allocators/issues/23"
+ )]
+ non_exhaustive: (),
+ },
+}
+
+#[unstable(
+ feature = "try_reserve_kind",
+ reason = "Uncertain how much info should be exposed",
+ issue = "48043"
+)]
+impl From<TryReserveErrorKind> for TryReserveError {
+ #[inline]
+ fn from(kind: TryReserveErrorKind) -> Self {
+ Self { kind }
+ }
+}
+
+#[unstable(feature = "try_reserve_kind", reason = "new API", issue = "48043")]
+impl From<LayoutError> for TryReserveErrorKind {
+ /// Always evaluates to [`TryReserveErrorKind::CapacityOverflow`].
+ #[inline]
+ fn from(_: LayoutError) -> Self {
+ TryReserveErrorKind::CapacityOverflow
+ }
+}
+
+#[stable(feature = "try_reserve", since = "1.57.0")]
+impl Display for TryReserveError {
+ fn fmt(
+ &self,
+ fmt: &mut core::fmt::Formatter<'_>,
+ ) -> core::result::Result<(), core::fmt::Error> {
+ fmt.write_str("memory allocation failed")?;
+ let reason = match self.kind {
+ TryReserveErrorKind::CapacityOverflow => {
+ " because the computed capacity exceeded the collection's maximum"
+ }
+ TryReserveErrorKind::AllocError { .. } => {
+ " because the memory allocator returned a error"
+ }
+ };
+ fmt.write_str(reason)
+ }
+}
+
+/// An intermediate trait for specialization of `Extend`.
+#[doc(hidden)]
+trait SpecExtend<I: IntoIterator> {
+ /// Extends `self` with the contents of the given iterator.
+ fn spec_extend(&mut self, iter: I);
+}
diff --git a/rust/alloc/fmt.rs b/rust/alloc/fmt.rs
new file mode 100644
index 000000000000..aeb7554f8e91
--- /dev/null
+++ b/rust/alloc/fmt.rs
@@ -0,0 +1,599 @@
+//! Utilities for formatting and printing `String`s.
+//!
+//! This module contains the runtime support for the [`format!`] syntax extension.
+//! This macro is implemented in the compiler to emit calls to this module in
+//! order to format arguments at runtime into strings.
+//!
+//! # Usage
+//!
+//! The [`format!`] macro is intended to be familiar to those coming from C's
+//! `printf`/`fprintf` functions or Python's `str.format` function.
+//!
+//! Some examples of the [`format!`] extension are:
+//!
+//! ```
+//! format!("Hello"); // => "Hello"
+//! format!("Hello, {}!", "world"); // => "Hello, world!"
+//! format!("The number is {}", 1); // => "The number is 1"
+//! format!("{:?}", (3, 4)); // => "(3, 4)"
+//! format!("{value}", value=4); // => "4"
+//! let people = "Rustaceans";
+//! format!("Hello {people}!"); // => "Hello Rustaceans!"
+//! format!("{} {}", 1, 2); // => "1 2"
+//! format!("{:04}", 42); // => "0042" with leading zeros
+//! format!("{:#?}", (100, 200)); // => "(
+//! // 100,
+//! // 200,
+//! // )"
+//! ```
+//!
+//! From these, you can see that the first argument is a format string. It is
+//! required by the compiler for this to be a string literal; it cannot be a
+//! variable passed in (in order to perform validity checking). The compiler
+//! will then parse the format string and determine if the list of arguments
+//! provided is suitable to pass to this format string.
+//!
+//! To convert a single value to a string, use the [`to_string`] method. This
+//! will use the [`Display`] formatting trait.
+//!
+//! ## Positional parameters
+//!
+//! Each formatting argument is allowed to specify which value argument it's
+//! referencing, and if omitted it is assumed to be "the next argument". For
+//! example, the format string `{} {} {}` would take three parameters, and they
+//! would be formatted in the same order as they're given. The format string
+//! `{2} {1} {0}`, however, would format arguments in reverse order.
+//!
+//! Things can get a little tricky once you start intermingling the two types of
+//! positional specifiers. The "next argument" specifier can be thought of as an
+//! iterator over the argument. Each time a "next argument" specifier is seen,
+//! the iterator advances. This leads to behavior like this:
+//!
+//! ```
+//! format!("{1} {} {0} {}", 1, 2); // => "2 1 1 2"
+//! ```
+//!
+//! The internal iterator over the argument has not been advanced by the time
+//! the first `{}` is seen, so it prints the first argument. Then upon reaching
+//! the second `{}`, the iterator has advanced forward to the second argument.
+//! Essentially, parameters that explicitly name their argument do not affect
+//! parameters that do not name an argument in terms of positional specifiers.
+//!
+//! A format string is required to use all of its arguments, otherwise it is a
+//! compile-time error. You may refer to the same argument more than once in the
+//! format string.
+//!
+//! ## Named parameters
+//!
+//! Rust itself does not have a Python-like equivalent of named parameters to a
+//! function, but the [`format!`] macro is a syntax extension that allows it to
+//! leverage named parameters. Named parameters are listed at the end of the
+//! argument list and have the syntax:
+//!
+//! ```text
+//! identifier '=' expression
+//! ```
+//!
+//! For example, the following [`format!`] expressions all use named arguments:
+//!
+//! ```
+//! format!("{argument}", argument = "test"); // => "test"
+//! format!("{name} {}", 1, name = 2); // => "2 1"
+//! format!("{a} {c} {b}", a="a", b='b', c=3); // => "a 3 b"
+//! ```
+//!
+//! If a named parameter does not appear in the argument list, `format!` will
+//! reference a variable with that name in the current scope.
+//!
+//! ```
+//! let argument = 2 + 2;
+//! format!("{argument}"); // => "4"
+//!
+//! fn make_string(a: u32, b: &str) -> String {
+//! format!("{b} {a}")
+//! }
+//! make_string(927, "label"); // => "label 927"
+//! ```
+//!
+//! It is not valid to put positional parameters (those without names) after
+//! arguments that have names. Like with positional parameters, it is not
+//! valid to provide named parameters that are unused by the format string.
+//!
+//! # Formatting Parameters
+//!
+//! Each argument being formatted can be transformed by a number of formatting
+//! parameters (corresponding to `format_spec` in [the syntax](#syntax)). These
+//! parameters affect the string representation of what's being formatted.
+//!
+//! ## Width
+//!
+//! ```
+//! // All of these print "Hello x !"
+//! println!("Hello {:5}!", "x");
+//! println!("Hello {:1$}!", "x", 5);
+//! println!("Hello {1:0$}!", 5, "x");
+//! println!("Hello {:width$}!", "x", width = 5);
+//! let width = 5;
+//! println!("Hello {:width$}!", "x");
+//! ```
+//!
+//! This is a parameter for the "minimum width" that the format should take up.
+//! If the value's string does not fill up this many characters, then the
+//! padding specified by fill/alignment will be used to take up the required
+//! space (see below).
+//!
+//! The value for the width can also be provided as a [`usize`] in the list of
+//! parameters by adding a postfix `$`, indicating that the second argument is
+//! a [`usize`] specifying the width.
+//!
+//! Referring to an argument with the dollar syntax does not affect the "next
+//! argument" counter, so it's usually a good idea to refer to arguments by
+//! position, or use named arguments.
+//!
+//! ## Fill/Alignment
+//!
+//! ```
+//! assert_eq!(format!("Hello {:<5}!", "x"), "Hello x !");
+//! assert_eq!(format!("Hello {:-<5}!", "x"), "Hello x----!");
+//! assert_eq!(format!("Hello {:^5}!", "x"), "Hello x !");
+//! assert_eq!(format!("Hello {:>5}!", "x"), "Hello x!");
+//! ```
+//!
+//! The optional fill character and alignment is provided normally in conjunction with the
+//! [`width`](#width) parameter. It must be defined before `width`, right after the `:`.
+//! This indicates that if the value being formatted is smaller than
+//! `width` some extra characters will be printed around it.
+//! Filling comes in the following variants for different alignments:
+//!
+//! * `[fill]<` - the argument is left-aligned in `width` columns
+//! * `[fill]^` - the argument is center-aligned in `width` columns
+//! * `[fill]>` - the argument is right-aligned in `width` columns
+//!
+//! The default [fill/alignment](#fillalignment) for non-numerics is a space and
+//! left-aligned. The
+//! default for numeric formatters is also a space character but with right-alignment. If
+//! the `0` flag (see below) is specified for numerics, then the implicit fill character is
+//! `0`.
+//!
+//! Note that alignment might not be implemented by some types. In particular, it
+//! is not generally implemented for the `Debug` trait. A good way to ensure
+//! padding is applied is to format your input, then pad this resulting string
+//! to obtain your output:
+//!
+//! ```
+//! println!("Hello {:^15}!", format!("{:?}", Some("hi"))); // => "Hello Some("hi") !"
+//! ```
+//!
+//! ## Sign/`#`/`0`
+//!
+//! ```
+//! assert_eq!(format!("Hello {:+}!", 5), "Hello +5!");
+//! assert_eq!(format!("{:#x}!", 27), "0x1b!");
+//! assert_eq!(format!("Hello {:05}!", 5), "Hello 00005!");
+//! assert_eq!(format!("Hello {:05}!", -5), "Hello -0005!");
+//! assert_eq!(format!("{:#010x}!", 27), "0x0000001b!");
+//! ```
+//!
+//! These are all flags altering the behavior of the formatter.
+//!
+//! * `+` - This is intended for numeric types and indicates that the sign
+//! should always be printed. Positive signs are never printed by
+//! default, and the negative sign is only printed by default for signed values.
+//! This flag indicates that the correct sign (`+` or `-`) should always be printed.
+//! * `-` - Currently not used
+//! * `#` - This flag indicates that the "alternate" form of printing should
+//! be used. The alternate forms are:
+//! * `#?` - pretty-print the [`Debug`] formatting (adds linebreaks and indentation)
+//! * `#x` - precedes the argument with a `0x`
+//! * `#X` - precedes the argument with a `0x`
+//! * `#b` - precedes the argument with a `0b`
+//! * `#o` - precedes the argument with a `0o`
+//! * `0` - This is used to indicate for integer formats that the padding to `width` should
+//! both be done with a `0` character as well as be sign-aware. A format
+//! like `{:08}` would yield `00000001` for the integer `1`, while the
+//! same format would yield `-0000001` for the integer `-1`. Notice that
+//! the negative version has one fewer zero than the positive version.
+//! Note that padding zeros are always placed after the sign (if any)
+//! and before the digits. When used together with the `#` flag, a similar
+//! rule applies: padding zeros are inserted after the prefix but before
+//! the digits. The prefix is included in the total width.
+//!
+//! ## Precision
+//!
+//! For non-numeric types, this can be considered a "maximum width". If the resulting string is
+//! longer than this width, then it is truncated down to this many characters and that truncated
+//! value is emitted with proper `fill`, `alignment` and `width` if those parameters are set.
+//!
+//! For integral types, this is ignored.
+//!
+//! For floating-point types, this indicates how many digits after the decimal point should be
+//! printed.
+//!
+//! There are three possible ways to specify the desired `precision`:
+//!
+//! 1. An integer `.N`:
+//!
+//! the integer `N` itself is the precision.
+//!
+//! 2. An integer or name followed by dollar sign `.N$`:
+//!
+//! use format *argument* `N` (which must be a `usize`) as the precision.
+//!
+//! 3. An asterisk `.*`:
+//!
+//! `.*` means that this `{...}` is associated with *two* format inputs rather than one: the
+//! first input holds the `usize` precision, and the second holds the value to print. Note that
+//! in this case, if one uses the format string `{<arg>:<spec>.*}`, then the `<arg>` part refers
+//! to the *value* to print, and the `precision` must come in the input preceding `<arg>`.
+//!
+//! For example, the following calls all print the same thing `Hello x is 0.01000`:
+//!
+//! ```
+//! // Hello {arg 0 ("x")} is {arg 1 (0.01) with precision specified inline (5)}
+//! println!("Hello {0} is {1:.5}", "x", 0.01);
+//!
+//! // Hello {arg 1 ("x")} is {arg 2 (0.01) with precision specified in arg 0 (5)}
+//! println!("Hello {1} is {2:.0$}", 5, "x", 0.01);
+//!
+//! // Hello {arg 0 ("x")} is {arg 2 (0.01) with precision specified in arg 1 (5)}
+//! println!("Hello {0} is {2:.1$}", "x", 5, 0.01);
+//!
+//! // Hello {next arg ("x")} is {second of next two args (0.01) with precision
+//! // specified in first of next two args (5)}
+//! println!("Hello {} is {:.*}", "x", 5, 0.01);
+//!
+//! // Hello {next arg ("x")} is {arg 2 (0.01) with precision
+//! // specified in its predecessor (5)}
+//! println!("Hello {} is {2:.*}", "x", 5, 0.01);
+//!
+//! // Hello {next arg ("x")} is {arg "number" (0.01) with precision specified
+//! // in arg "prec" (5)}
+//! println!("Hello {} is {number:.prec$}", "x", prec = 5, number = 0.01);
+//! ```
+//!
+//! While these:
+//!
+//! ```
+//! println!("{}, `{name:.*}` has 3 fractional digits", "Hello", 3, name=1234.56);
+//! println!("{}, `{name:.*}` has 3 characters", "Hello", 3, name="1234.56");
+//! println!("{}, `{name:>8.*}` has 3 right-aligned characters", "Hello", 3, name="1234.56");
+//! ```
+//!
+//! print three significantly different things:
+//!
+//! ```text
+//! Hello, `1234.560` has 3 fractional digits
+//! Hello, `123` has 3 characters
+//! Hello, ` 123` has 3 right-aligned characters
+//! ```
+//!
+//! ## Localization
+//!
+//! In some programming languages, the behavior of string formatting functions
+//! depends on the operating system's locale setting. The format functions
+//! provided by Rust's standard library do not have any concept of locale and
+//! will produce the same results on all systems regardless of user
+//! configuration.
+//!
+//! For example, the following code will always print `1.5` even if the system
+//! locale uses a decimal separator other than a dot.
+//!
+//! ```
+//! println!("The value is {}", 1.5);
+//! ```
+//!
+//! # Escaping
+//!
+//! The literal characters `{` and `}` may be included in a string by preceding
+//! them with the same character. For example, the `{` character is escaped with
+//! `{{` and the `}` character is escaped with `}}`.
+//!
+//! ```
+//! assert_eq!(format!("Hello {{}}"), "Hello {}");
+//! assert_eq!(format!("{{ Hello"), "{ Hello");
+//! ```
+//!
+//! # Syntax
+//!
+//! To summarize, here you can find the full grammar of format strings.
+//! The syntax for the formatting language used is drawn from other languages,
+//! so it should not be too alien. Arguments are formatted with Python-like
+//! syntax, meaning that arguments are surrounded by `{}` instead of the C-like
+//! `%`. The actual grammar for the formatting syntax is:
+//!
+//! ```text
+//! format_string := text [ maybe_format text ] *
+//! maybe_format := '{' '{' | '}' '}' | format
+//! format := '{' [ argument ] [ ':' format_spec ] '}'
+//! argument := integer | identifier
+//!
+//! format_spec := [[fill]align][sign]['#']['0'][width]['.' precision]type
+//! fill := character
+//! align := '<' | '^' | '>'
+//! sign := '+' | '-'
+//! width := count
+//! precision := count | '*'
+//! type := '' | '?' | 'x?' | 'X?' | identifier
+//! count := parameter | integer
+//! parameter := argument '$'
+//! ```
+//! In the above grammar, `text` must not contain any `'{'` or `'}'` characters.
+//!
+//! # Formatting traits
+//!
+//! When requesting that an argument be formatted with a particular type, you
+//! are actually requesting that an argument ascribes to a particular trait.
+//! This allows multiple actual types to be formatted via `{:x}` (like [`i8`] as
+//! well as [`isize`]). The current mapping of types to traits is:
+//!
+//! * *nothing* ⇒ [`Display`]
+//! * `?` ⇒ [`Debug`]
+//! * `x?` ⇒ [`Debug`] with lower-case hexadecimal integers
+//! * `X?` ⇒ [`Debug`] with upper-case hexadecimal integers
+//! * `o` ⇒ [`Octal`]
+//! * `x` ⇒ [`LowerHex`]
+//! * `X` ⇒ [`UpperHex`]
+//! * `p` ⇒ [`Pointer`]
+//! * `b` ⇒ [`Binary`]
+//! * `e` ⇒ [`LowerExp`]
+//! * `E` ⇒ [`UpperExp`]
+//!
+//! What this means is that any type of argument which implements the
+//! [`fmt::Binary`][`Binary`] trait can then be formatted with `{:b}`. Implementations
+//! are provided for these traits for a number of primitive types by the
+//! standard library as well. If no format is specified (as in `{}` or `{:6}`),
+//! then the format trait used is the [`Display`] trait.
+//!
+//! When implementing a format trait for your own type, you will have to
+//! implement a method of the signature:
+//!
+//! ```
+//! # #![allow(dead_code)]
+//! # use std::fmt;
+//! # struct Foo; // our custom type
+//! # impl fmt::Display for Foo {
+//! fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//! # write!(f, "testing, testing")
+//! # } }
+//! ```
+//!
+//! Your type will be passed as `self` by-reference, and then the function
+//! should emit output into the `f.buf` stream. It is up to each format trait
+//! implementation to correctly adhere to the requested formatting parameters.
+//! The values of these parameters will be listed in the fields of the
+//! [`Formatter`] struct. In order to help with this, the [`Formatter`] struct also
+//! provides some helper methods.
+//!
+//! Additionally, the return value of this function is [`fmt::Result`] which is a
+//! type alias of <code>[Result]<(), [std::fmt::Error]></code>. Formatting implementations
+//! should ensure that they propagate errors from the [`Formatter`] (e.g., when
+//! calling [`write!`]). However, they should never return errors spuriously. That
+//! is, a formatting implementation must and may only return an error if the
+//! passed-in [`Formatter`] returns an error. This is because, contrary to what
+//! the function signature might suggest, string formatting is an infallible
+//! operation. This function only returns a result because writing to the
+//! underlying stream might fail and it must provide a way to propagate the fact
+//! that an error has occurred back up the stack.
+//!
+//! An example of implementing the formatting traits would look
+//! like:
+//!
+//! ```
+//! use std::fmt;
+//!
+//! #[derive(Debug)]
+//! struct Vector2D {
+//! x: isize,
+//! y: isize,
+//! }
+//!
+//! impl fmt::Display for Vector2D {
+//! fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//! // The `f` value implements the `Write` trait, which is what the
+//! // write! macro is expecting. Note that this formatting ignores the
+//! // various flags provided to format strings.
+//! write!(f, "({}, {})", self.x, self.y)
+//! }
+//! }
+//!
+//! // Different traits allow different forms of output of a type. The meaning
+//! // of this format is to print the magnitude of a vector.
+//! impl fmt::Binary for Vector2D {
+//! fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//! let magnitude = (self.x * self.x + self.y * self.y) as f64;
+//! let magnitude = magnitude.sqrt();
+//!
+//! // Respect the formatting flags by using the helper method
+//! // `pad_integral` on the Formatter object. See the method
+//! // documentation for details, and the function `pad` can be used
+//! // to pad strings.
+//! let decimals = f.precision().unwrap_or(3);
+//! let string = format!("{:.*}", decimals, magnitude);
+//! f.pad_integral(true, "", &string)
+//! }
+//! }
+//!
+//! fn main() {
+//! let myvector = Vector2D { x: 3, y: 4 };
+//!
+//! println!("{}", myvector); // => "(3, 4)"
+//! println!("{:?}", myvector); // => "Vector2D {x: 3, y:4}"
+//! println!("{:10.3b}", myvector); // => " 5.000"
+//! }
+//! ```
+//!
+//! ### `fmt::Display` vs `fmt::Debug`
+//!
+//! These two formatting traits have distinct purposes:
+//!
+//! - [`fmt::Display`][`Display`] implementations assert that the type can be faithfully
+//! represented as a UTF-8 string at all times. It is **not** expected that
+//! all types implement the [`Display`] trait.
+//! - [`fmt::Debug`][`Debug`] implementations should be implemented for **all** public types.
+//! Output will typically represent the internal state as faithfully as possible.
+//! The purpose of the [`Debug`] trait is to facilitate debugging Rust code. In
+//! most cases, using `#[derive(Debug)]` is sufficient and recommended.
+//!
+//! Some examples of the output from both traits:
+//!
+//! ```
+//! assert_eq!(format!("{} {:?}", 3, 4), "3 4");
+//! assert_eq!(format!("{} {:?}", 'a', 'b'), "a 'b'");
+//! assert_eq!(format!("{} {:?}", "foo\n", "bar\n"), "foo\n \"bar\\n\"");
+//! ```
+//!
+//! # Related macros
+//!
+//! There are a number of related macros in the [`format!`] family. The ones that
+//! are currently implemented are:
+//!
+//! ```ignore (only-for-syntax-highlight)
+//! format! // described above
+//! write! // first argument is a &mut io::Write, the destination
+//! writeln! // same as write but appends a newline
+//! print! // the format string is printed to the standard output
+//! println! // same as print but appends a newline
+//! eprint! // the format string is printed to the standard error
+//! eprintln! // same as eprint but appends a newline
+//! format_args! // described below.
+//! ```
+//!
+//! ### `write!`
+//!
+//! This and [`writeln!`] are two macros which are used to emit the format string
+//! to a specified stream. This is used to prevent intermediate allocations of
+//! format strings and instead directly write the output. Under the hood, this
+//! function is actually invoking the [`write_fmt`] function defined on the
+//! [`std::io::Write`] trait. Example usage is:
+//!
+//! ```
+//! # #![allow(unused_must_use)]
+//! use std::io::Write;
+//! let mut w = Vec::new();
+//! write!(&mut w, "Hello {}!", "world");
+//! ```
+//!
+//! ### `print!`
+//!
+//! This and [`println!`] emit their output to stdout. Similarly to the [`write!`]
+//! macro, the goal of these macros is to avoid intermediate allocations when
+//! printing output. Example usage is:
+//!
+//! ```
+//! print!("Hello {}!", "world");
+//! println!("I have a newline {}", "character at the end");
+//! ```
+//! ### `eprint!`
+//!
+//! The [`eprint!`] and [`eprintln!`] macros are identical to
+//! [`print!`] and [`println!`], respectively, except they emit their
+//! output to stderr.
+//!
+//! ### `format_args!`
+//!
+//! This is a curious macro used to safely pass around
+//! an opaque object describing the format string. This object
+//! does not require any heap allocations to create, and it only
+//! references information on the stack. Under the hood, all of
+//! the related macros are implemented in terms of this. First
+//! off, some example usage is:
+//!
+//! ```
+//! # #![allow(unused_must_use)]
+//! use std::fmt;
+//! use std::io::{self, Write};
+//!
+//! let mut some_writer = io::stdout();
+//! write!(&mut some_writer, "{}", format_args!("print with a {}", "macro"));
+//!
+//! fn my_fmt_fn(args: fmt::Arguments) {
+//! write!(&mut io::stdout(), "{}", args);
+//! }
+//! my_fmt_fn(format_args!(", or a {} too", "function"));
+//! ```
+//!
+//! The result of the [`format_args!`] macro is a value of type [`fmt::Arguments`].
+//! This structure can then be passed to the [`write`] and [`format`] functions
+//! inside this module in order to process the format string.
+//! The goal of this macro is to even further prevent intermediate allocations
+//! when dealing with formatting strings.
+//!
+//! For example, a logging library could use the standard formatting syntax, but
+//! it would internally pass around this structure until it has been determined
+//! where output should go to.
+//!
+//! [`fmt::Result`]: Result "fmt::Result"
+//! [Result]: core::result::Result "std::result::Result"
+//! [std::fmt::Error]: Error "fmt::Error"
+//! [`write`]: write() "fmt::write"
+//! [`to_string`]: crate::string::ToString::to_string "ToString::to_string"
+//! [`write_fmt`]: ../../std/io/trait.Write.html#method.write_fmt
+//! [`std::io::Write`]: ../../std/io/trait.Write.html
+//! [`print!`]: ../../std/macro.print.html "print!"
+//! [`println!`]: ../../std/macro.println.html "println!"
+//! [`eprint!`]: ../../std/macro.eprint.html "eprint!"
+//! [`eprintln!`]: ../../std/macro.eprintln.html "eprintln!"
+//! [`fmt::Arguments`]: Arguments "fmt::Arguments"
+//! [`format`]: format() "fmt::format"
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[unstable(feature = "fmt_internals", issue = "none")]
+pub use core::fmt::rt;
+#[stable(feature = "fmt_flags_align", since = "1.28.0")]
+pub use core::fmt::Alignment;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::Error;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{write, ArgumentV1, Arguments};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Binary, Octal};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Debug, Display};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{DebugList, DebugMap, DebugSet, DebugStruct, DebugTuple};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Formatter, Result, Write};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{LowerExp, UpperExp};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{LowerHex, Pointer, UpperHex};
+
+#[cfg(not(no_global_oom_handling))]
+use crate::string;
+
+/// The `format` function takes an [`Arguments`] struct and returns the resulting
+/// formatted string.
+///
+/// The [`Arguments`] instance can be created with the [`format_args!`] macro.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// use std::fmt;
+///
+/// let s = fmt::format(format_args!("Hello, {}!", "world"));
+/// assert_eq!(s, "Hello, world!");
+/// ```
+///
+/// Please note that using [`format!`] might be preferable.
+/// Example:
+///
+/// ```
+/// let s = format!("Hello, {}!", "world");
+/// assert_eq!(s, "Hello, world!");
+/// ```
+///
+/// [`format_args!`]: core::format_args
+/// [`format!`]: crate::format
+#[cfg(not(no_global_oom_handling))]
+#[must_use]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn format(args: Arguments<'_>) -> string::String {
+ let capacity = args.estimated_capacity();
+ let mut output = string::String::with_capacity(capacity);
+ output.write_fmt(args).expect("a formatting trait implementation returned an error");
+ output
+}
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
new file mode 100644
index 000000000000..6da32df57efb
--- /dev/null
+++ b/rust/alloc/lib.rs
@@ -0,0 +1,223 @@
+//! # The Rust core allocation and collections library
+//!
+//! This library provides smart pointers and collections for managing
+//! heap-allocated values.
+//!
+//! This library, like libcore, normally doesn’t need to be used directly
+//! since its contents are re-exported in the [`std` crate](../std/index.html).
+//! Crates that use the `#![no_std]` attribute however will typically
+//! not depend on `std`, so they’d use this crate instead.
+//!
+//! ## Boxed values
+//!
+//! The [`Box`] type is a smart pointer type. There can only be one owner of a
+//! [`Box`], and the owner can decide to mutate the contents, which live on the
+//! heap.
+//!
+//! This type can be sent among threads efficiently as the size of a `Box` value
+//! is the same as that of a pointer. Tree-like data structures are often built
+//! with boxes because each node often has only one owner, the parent.
+//!
+//! ## Reference counted pointers
+//!
+//! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended
+//! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and
+//! only allows access to `&T`, a shared reference.
+//!
+//! This type is useful when inherited mutability (such as using [`Box`]) is too
+//! constraining for an application, and is often paired with the [`Cell`] or
+//! [`RefCell`] types in order to allow mutation.
+//!
+//! ## Atomically reference counted pointers
+//!
+//! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It
+//! provides all the same functionality of [`Rc`], except it requires that the
+//! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself
+//! sendable while [`Rc<T>`][`Rc`] is not.
+//!
+//! This type allows for shared access to the contained data, and is often
+//! paired with synchronization primitives such as mutexes to allow mutation of
+//! shared resources.
+//!
+//! ## Collections
+//!
+//! Implementations of the most common general purpose data structures are
+//! defined in this library. They are re-exported through the
+//! [standard collections library](../std/collections/index.html).
+//!
+//! ## Heap interfaces
+//!
+//! The [`alloc`](alloc/index.html) module defines the low-level interface to the
+//! default global allocator. It is not compatible with the libc allocator API.
+//!
+//! [`Arc`]: sync
+//! [`Box`]: boxed
+//! [`Cell`]: core::cell
+//! [`Rc`]: rc
+//! [`RefCell`]: core::cell
+
+// To run liballoc tests without x.py without ending up with two copies of liballoc, Miri needs to be
+// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
+// rustc itself never sets the feature, so this line has no affect there.
+#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
+#![allow(unused_attributes)]
+#![stable(feature = "alloc", since = "1.36.0")]
+#![doc(
+ html_playground_url = "https://play.rust-lang.org/",
+ issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
+ test(no_crate_inject, attr(allow(unused_variables), deny(warnings)))
+)]
+#![doc(cfg_hide(
+ not(test),
+ not(any(test, bootstrap)),
+ any(not(feature = "miri-test-libstd"), test, doctest),
+ no_global_oom_handling,
+ not(no_global_oom_handling),
+ target_has_atomic = "ptr"
+))]
+#![no_std]
+#![needs_allocator]
+//
+// Lints:
+#![deny(unsafe_op_in_unsafe_fn)]
+#![warn(deprecated_in_future)]
+#![warn(missing_debug_implementations)]
+#![warn(missing_docs)]
+#![allow(explicit_outlives_requirements)]
+//
+// Library features:
+#![feature(alloc_layout_extra)]
+#![feature(allocator_api)]
+#![feature(array_chunks)]
+#![feature(array_methods)]
+#![feature(array_windows)]
+#![feature(async_iterator)]
+#![feature(coerce_unsized)]
+#![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))]
+#![feature(const_box)]
+#![cfg_attr(not(no_global_oom_handling), feature(const_btree_new))]
+#![feature(const_cow_is_borrowed)]
+#![feature(const_convert)]
+#![feature(const_size_of_val)]
+#![feature(const_align_of_val)]
+#![feature(const_ptr_read)]
+#![feature(const_maybe_uninit_write)]
+#![feature(const_maybe_uninit_as_mut_ptr)]
+#![feature(const_refs_to_cell)]
+#![feature(core_intrinsics)]
+#![feature(const_eval_select)]
+#![feature(const_pin)]
+#![feature(dispatch_from_dyn)]
+#![feature(exact_size_is_empty)]
+#![feature(extend_one)]
+#![feature(fmt_internals)]
+#![feature(fn_traits)]
+#![feature(inplace_iteration)]
+#![feature(iter_advance_by)]
+#![feature(layout_for_ptr)]
+#![feature(maybe_uninit_slice)]
+#![cfg_attr(test, feature(new_uninit))]
+#![feature(nonnull_slice_from_raw_parts)]
+#![feature(pattern)]
+#![feature(ptr_internals)]
+#![feature(receiver_trait)]
+#![feature(set_ptr_value)]
+#![feature(slice_group_by)]
+#![feature(slice_ptr_get)]
+#![feature(slice_ptr_len)]
+#![feature(slice_range)]
+#![feature(str_internals)]
+#![feature(trusted_len)]
+#![feature(trusted_random_access)]
+#![feature(try_trait_v2)]
+#![feature(unicode_internals)]
+#![feature(unsize)]
+//
+// Language features:
+#![feature(allocator_internals)]
+#![feature(allow_internal_unstable)]
+#![feature(associated_type_bounds)]
+#![feature(box_syntax)]
+#![feature(cfg_sanitize)]
+#![cfg_attr(bootstrap, feature(cfg_target_has_atomic))]
+#![feature(const_deref)]
+#![feature(const_fn_trait_bound)]
+#![feature(const_mut_refs)]
+#![feature(const_ptr_write)]
+#![feature(const_precise_live_drops)]
+#![feature(const_trait_impl)]
+#![feature(const_try)]
+#![feature(dropck_eyepatch)]
+#![feature(exclusive_range_pattern)]
+#![feature(fundamental)]
+#![cfg_attr(not(test), feature(generator_trait))]
+#![feature(lang_items)]
+#![feature(min_specialization)]
+#![feature(negative_impls)]
+#![feature(never_type)]
+#![feature(nll)] // Not necessary, but here to test the `nll` feature.
+#![feature(rustc_allow_const_fn_unstable)]
+#![feature(rustc_attrs)]
+#![feature(staged_api)]
+#![cfg_attr(test, feature(test))]
+#![feature(unboxed_closures)]
+#![feature(unsized_fn_params)]
+#![feature(c_unwind)]
+//
+// Rustdoc features:
+#![feature(doc_cfg)]
+#![feature(doc_cfg_hide)]
+// Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
+// blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
+// that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs
+// from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
+#![feature(intra_doc_pointers)]
+
+// Allow testing this library
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+#[cfg(test)]
+extern crate test;
+
+// Module with internal macros used by other modules (needs to be included before other modules).
+#[macro_use]
+mod macros;
+
+mod raw_vec;
+
+// Heaps provided for low-level allocation strategies
+
+pub mod alloc;
+
+// Primitive types using the heaps above
+
+// Need to conditionally define the mod from `boxed.rs` to avoid
+// duplicating the lang-items when building in test cfg; but also need
+// to allow code to have `use boxed::Box;` declarations.
+#[cfg(not(test))]
+pub mod boxed;
+#[cfg(test)]
+mod boxed {
+ pub use std::boxed::Box;
+}
+pub mod borrow;
+pub mod collections;
+pub mod fmt;
+pub mod rc;
+pub mod slice;
+pub mod str;
+pub mod string;
+#[cfg(target_has_atomic = "ptr")]
+pub mod sync;
+#[cfg(all(not(no_global_oom_handling), target_has_atomic = "ptr"))]
+pub mod task;
+#[cfg(test)]
+mod tests;
+pub mod vec;
+
+#[doc(hidden)]
+#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
+pub mod __export {
+ pub use core::format_args;
+}
diff --git a/rust/alloc/macros.rs b/rust/alloc/macros.rs
new file mode 100644
index 000000000000..d3e9e65c3fe5
--- /dev/null
+++ b/rust/alloc/macros.rs
@@ -0,0 +1,125 @@
+/// Creates a [`Vec`] containing the arguments.
+///
+/// `vec!` allows `Vec`s to be defined with the same syntax as array expressions.
+/// There are two forms of this macro:
+///
+/// - Create a [`Vec`] containing a given list of elements:
+///
+/// ```
+/// let v = vec![1, 2, 3];
+/// assert_eq!(v[0], 1);
+/// assert_eq!(v[1], 2);
+/// assert_eq!(v[2], 3);
+/// ```
+///
+/// - Create a [`Vec`] from a given element and size:
+///
+/// ```
+/// let v = vec![1; 3];
+/// assert_eq!(v, [1, 1, 1]);
+/// ```
+///
+/// Note that unlike array expressions this syntax supports all elements
+/// which implement [`Clone`] and the number of elements doesn't have to be
+/// a constant.
+///
+/// This will use `clone` to duplicate an expression, so one should be careful
+/// using this with types having a nonstandard `Clone` implementation. For
+/// example, `vec![Rc::new(1); 5]` will create a vector of five references
+/// to the same boxed integer value, not five references pointing to independently
+/// boxed integers.
+///
+/// Also, note that `vec![expr; 0]` is allowed, and produces an empty vector.
+/// This will still evaluate `expr`, however, and immediately drop the resulting value, so
+/// be mindful of side effects.
+///
+/// [`Vec`]: crate::vec::Vec
+#[cfg(not(test))]
+#[macro_export]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_diagnostic_item = "vec_macro"]
+#[allow_internal_unstable(box_syntax, liballoc_internals)]
+macro_rules! vec {
+ () => (
+ $crate::__rust_force_expr!($crate::vec::Vec::new())
+ );
+ ($elem:expr; $n:expr) => (
+ $crate::__rust_force_expr!($crate::vec::from_elem($elem, $n))
+ );
+ ($($x:expr),+ $(,)?) => (
+ $crate::__rust_force_expr!(<[_]>::into_vec(box [$($x),+]))
+ );
+}
+
+// HACK(japaric): with cfg(test) the inherent `[T]::into_vec` method, which is
+// required for this macro definition, is not available. Instead use the
+// `slice::into_vec` function which is only available with cfg(test)
+// NB see the slice::hack module in slice.rs for more information
+#[cfg(test)]
+macro_rules! vec {
+ () => (
+ $crate::vec::Vec::new()
+ );
+ ($elem:expr; $n:expr) => (
+ $crate::vec::from_elem($elem, $n)
+ );
+ ($($x:expr),*) => (
+ $crate::slice::into_vec(box [$($x),*])
+ );
+ ($($x:expr,)*) => (vec![$($x),*])
+}
+
+/// Creates a `String` using interpolation of runtime expressions.
+///
+/// The first argument `format!` receives is a format string. This must be a string
+/// literal. The power of the formatting string is in the `{}`s contained.
+///
+/// Additional parameters passed to `format!` replace the `{}`s within the
+/// formatting string in the order given unless named or positional parameters
+/// are used; see [`std::fmt`] for more information.
+///
+/// A common use for `format!` is concatenation and interpolation of strings.
+/// The same convention is used with [`print!`] and [`write!`] macros,
+/// depending on the intended destination of the string.
+///
+/// To convert a single value to a string, use the [`to_string`] method. This
+/// will use the [`Display`] formatting trait.
+///
+/// [`std::fmt`]: ../std/fmt/index.html
+/// [`print!`]: ../std/macro.print.html
+/// [`write!`]: core::write
+/// [`to_string`]: crate::string::ToString
+/// [`Display`]: core::fmt::Display
+///
+/// # Panics
+///
+/// `format!` panics if a formatting trait implementation returns an error.
+/// This indicates an incorrect implementation
+/// since `fmt::Write for String` never returns an error itself.
+///
+/// # Examples
+///
+/// ```
+/// format!("test");
+/// format!("hello {}", "world!");
+/// format!("x = {}, y = {y}", 10, y = 30);
+/// ```
+#[macro_export]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "format_macro")]
+macro_rules! format {
+ ($($arg:tt)*) => {{
+ let res = $crate::fmt::format($crate::__export::format_args!($($arg)*));
+ res
+ }}
+}
+
+/// Force AST node to an expression to improve diagnostics in pattern position.
+#[doc(hidden)]
+#[macro_export]
+#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
+macro_rules! __rust_force_expr {
+ ($e:expr) => {
+ $e
+ };
+}
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
new file mode 100644
index 000000000000..8fa0242ca9a9
--- /dev/null
+++ b/rust/alloc/raw_vec.rs
@@ -0,0 +1,519 @@
+#![unstable(feature = "raw_vec_internals", reason = "unstable const warnings", issue = "none")]
+
+use core::alloc::LayoutError;
+use core::cmp;
+use core::intrinsics;
+use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::ops::Drop;
+use core::ptr::{self, NonNull, Unique};
+use core::slice;
+
+#[cfg(not(no_global_oom_handling))]
+use crate::alloc::handle_alloc_error;
+use crate::alloc::{Allocator, Global, Layout};
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::collections::TryReserveErrorKind::*;
+
+#[cfg(test)]
+mod tests;
+
+#[cfg(not(no_global_oom_handling))]
+enum AllocInit {
+ /// The contents of the new memory are uninitialized.
+ Uninitialized,
+ /// The new memory is guaranteed to be zeroed.
+ Zeroed,
+}
+
+/// A low-level utility for more ergonomically allocating, reallocating, and deallocating
+/// a buffer of memory on the heap without having to worry about all the corner cases
+/// involved. This type is excellent for building your own data structures like Vec and VecDeque.
+/// In particular:
+///
+/// * Produces `Unique::dangling()` on zero-sized types.
+/// * Produces `Unique::dangling()` on zero-length allocations.
+/// * Avoids freeing `Unique::dangling()`.
+/// * Catches all overflows in capacity computations (promotes them to "capacity overflow" panics).
+/// * Guards against 32-bit systems allocating more than isize::MAX bytes.
+/// * Guards against overflowing your length.
+/// * Calls `handle_alloc_error` for fallible allocations.
+/// * Contains a `ptr::Unique` and thus endows the user with all related benefits.
+/// * Uses the excess returned from the allocator to use the largest available capacity.
+///
+/// This type does not in anyway inspect the memory that it manages. When dropped it *will*
+/// free its memory, but it *won't* try to drop its contents. It is up to the user of `RawVec`
+/// to handle the actual things *stored* inside of a `RawVec`.
+///
+/// Note that the excess of a zero-sized types is always infinite, so `capacity()` always returns
+/// `usize::MAX`. This means that you need to be careful when round-tripping this type with a
+/// `Box<[T]>`, since `capacity()` won't yield the length.
+#[allow(missing_debug_implementations)]
+pub(crate) struct RawVec<T, A: Allocator = Global> {
+ ptr: Unique<T>,
+ cap: usize,
+ alloc: A,
+}
+
+impl<T> RawVec<T, Global> {
+ /// HACK(Centril): This exists because stable `const fn` can only call stable `const fn`, so
+ /// they cannot call `Self::new()`.
+ ///
+ /// If you change `RawVec<T>::new` or dependencies, please take care to not introduce anything
+ /// that would truly const-call something unstable.
+ pub const NEW: Self = Self::new();
+
+ /// Creates the biggest possible `RawVec` (on the system heap)
+ /// without allocating. If `T` has positive size, then this makes a
+ /// `RawVec` with capacity `0`. If `T` is zero-sized, then it makes a
+ /// `RawVec` with capacity `usize::MAX`. Useful for implementing
+ /// delayed allocation.
+ #[must_use]
+ pub const fn new() -> Self {
+ Self::new_in(Global)
+ }
+
+ /// Creates a `RawVec` (on the system heap) with exactly the
+ /// capacity and alignment requirements for a `[T; capacity]`. This is
+ /// equivalent to calling `RawVec::new` when `capacity` is `0` or `T` is
+ /// zero-sized. Note that if `T` is zero-sized this means you will
+ /// *not* get a `RawVec` with the requested capacity.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the requested capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Aborts
+ ///
+ /// Aborts on OOM.
+ #[cfg(not(any(no_global_oom_handling, test)))]
+ #[must_use]
+ #[inline]
+ pub fn with_capacity(capacity: usize) -> Self {
+ Self::with_capacity_in(capacity, Global)
+ }
+
+ /// Like `with_capacity`, but guarantees the buffer is zeroed.
+ #[cfg(not(any(no_global_oom_handling, test)))]
+ #[must_use]
+ #[inline]
+ pub fn with_capacity_zeroed(capacity: usize) -> Self {
+ Self::with_capacity_zeroed_in(capacity, Global)
+ }
+}
+
+impl<T, A: Allocator> RawVec<T, A> {
+ // Tiny Vecs are dumb. Skip to:
+ // - 8 if the element size is 1, because any heap allocators is likely
+ // to round up a request of less than 8 bytes to at least 8 bytes.
+ // - 4 if elements are moderate-sized (<= 1 KiB).
+ // - 1 otherwise, to avoid wasting too much space for very short Vecs.
+ pub(crate) const MIN_NON_ZERO_CAP: usize = if mem::size_of::<T>() == 1 {
+ 8
+ } else if mem::size_of::<T>() <= 1024 {
+ 4
+ } else {
+ 1
+ };
+
+ /// Like `new`, but parameterized over the choice of allocator for
+ /// the returned `RawVec`.
+ #[rustc_allow_const_fn_unstable(const_fn)]
+ pub const fn new_in(alloc: A) -> Self {
+ // `cap: 0` means "unallocated". zero-sized types are ignored.
+ Self { ptr: Unique::dangling(), cap: 0, alloc }
+ }
+
+ /// Like `with_capacity`, but parameterized over the choice of
+ /// allocator for the returned `RawVec`.
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
+ Self::allocate_in(capacity, AllocInit::Uninitialized, alloc)
+ }
+
+ /// Like `with_capacity_zeroed`, but parameterized over the choice
+ /// of allocator for the returned `RawVec`.
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ pub fn with_capacity_zeroed_in(capacity: usize, alloc: A) -> Self {
+ Self::allocate_in(capacity, AllocInit::Zeroed, alloc)
+ }
+
+ /// Converts the entire buffer into `Box<[MaybeUninit<T>]>` with the specified `len`.
+ ///
+ /// Note that this will correctly reconstitute any `cap` changes
+ /// that may have been performed. (See description of type for details.)
+ ///
+ /// # Safety
+ ///
+ /// * `len` must be greater than or equal to the most recently requested capacity, and
+ /// * `len` must be less than or equal to `self.capacity()`.
+ ///
+ /// Note, that the requested capacity and `self.capacity()` could differ, as
+ /// an allocator could overallocate and return a greater memory block than requested.
+ pub unsafe fn into_box(self, len: usize) -> Box<[MaybeUninit<T>], A> {
+ // Sanity-check one half of the safety requirement (we cannot check the other half).
+ debug_assert!(
+ len <= self.capacity(),
+ "`len` must be smaller than or equal to `self.capacity()`"
+ );
+
+ let me = ManuallyDrop::new(self);
+ unsafe {
+ let slice = slice::from_raw_parts_mut(me.ptr() as *mut MaybeUninit<T>, len);
+ Box::from_raw_in(slice, ptr::read(&me.alloc))
+ }
+ }
+
+ #[cfg(not(no_global_oom_handling))]
+ fn allocate_in(capacity: usize, init: AllocInit, alloc: A) -> Self {
+ if mem::size_of::<T>() == 0 {
+ Self::new_in(alloc)
+ } else {
+ // We avoid `unwrap_or_else` here because it bloats the amount of
+ // LLVM IR generated.
+ let layout = match Layout::array::<T>(capacity) {
+ Ok(layout) => layout,
+ Err(_) => capacity_overflow(),
+ };
+ match alloc_guard(layout.size()) {
+ Ok(_) => {}
+ Err(_) => capacity_overflow(),
+ }
+ let result = match init {
+ AllocInit::Uninitialized => alloc.allocate(layout),
+ AllocInit::Zeroed => alloc.allocate_zeroed(layout),
+ };
+ let ptr = match result {
+ Ok(ptr) => ptr,
+ Err(_) => handle_alloc_error(layout),
+ };
+
+ // Allocators currently return a `NonNull<[u8]>` whose length
+ // matches the size requested. If that ever changes, the capacity
+ // here should change to `ptr.len() / mem::size_of::<T>()`.
+ Self {
+ ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
+ cap: capacity,
+ alloc,
+ }
+ }
+ }
+
+ /// Reconstitutes a `RawVec` from a pointer, capacity, and allocator.
+ ///
+ /// # Safety
+ ///
+ /// The `ptr` must be allocated (via the given allocator `alloc`), and with the given
+ /// `capacity`.
+ /// The `capacity` cannot exceed `isize::MAX` for sized types. (only a concern on 32-bit
+ /// systems). ZST vectors may have a capacity up to `usize::MAX`.
+ /// If the `ptr` and `capacity` come from a `RawVec` created via `alloc`, then this is
+ /// guaranteed.
+ #[inline]
+ pub unsafe fn from_raw_parts_in(ptr: *mut T, capacity: usize, alloc: A) -> Self {
+ Self { ptr: unsafe { Unique::new_unchecked(ptr) }, cap: capacity, alloc }
+ }
+
+ /// Gets a raw pointer to the start of the allocation. Note that this is
+ /// `Unique::dangling()` if `capacity == 0` or `T` is zero-sized. In the former case, you must
+ /// be careful.
+ #[inline]
+ pub fn ptr(&self) -> *mut T {
+ self.ptr.as_ptr()
+ }
+
+ /// Gets the capacity of the allocation.
+ ///
+ /// This will always be `usize::MAX` if `T` is zero-sized.
+ #[inline(always)]
+ pub fn capacity(&self) -> usize {
+ if mem::size_of::<T>() == 0 { usize::MAX } else { self.cap }
+ }
+
+ /// Returns a shared reference to the allocator backing this `RawVec`.
+ pub fn allocator(&self) -> &A {
+ &self.alloc
+ }
+
+ fn current_memory(&self) -> Option<(NonNull<u8>, Layout)> {
+ if mem::size_of::<T>() == 0 || self.cap == 0 {
+ None
+ } else {
+ // We have an allocated chunk of memory, so we can bypass runtime
+ // checks to get our current layout.
+ unsafe {
+ let align = mem::align_of::<T>();
+ let size = mem::size_of::<T>() * self.cap;
+ let layout = Layout::from_size_align_unchecked(size, align);
+ Some((self.ptr.cast().into(), layout))
+ }
+ }
+ }
+
+ /// Ensures that the buffer contains at least enough space to hold `len +
+ /// additional` elements. If it doesn't already have enough capacity, will
+ /// reallocate enough space plus comfortable slack space to get amortized
+ /// *O*(1) behavior. Will limit this behavior if it would needlessly cause
+ /// itself to panic.
+ ///
+ /// If `len` exceeds `self.capacity()`, this may fail to actually allocate
+ /// the requested space. This is not really unsafe, but the unsafe
+ /// code *you* write that relies on the behavior of this function may break.
+ ///
+ /// This is ideal for implementing a bulk-push operation like `extend`.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Aborts
+ ///
+ /// Aborts on OOM.
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ pub fn reserve(&mut self, len: usize, additional: usize) {
+ // Callers expect this function to be very cheap when there is already sufficient capacity.
+ // Therefore, we move all the resizing and error-handling logic from grow_amortized and
+ // handle_reserve behind a call, while making sure that this function is likely to be
+ // inlined as just a comparison and a call if the comparison fails.
+ #[cold]
+ fn do_reserve_and_handle<T, A: Allocator>(
+ slf: &mut RawVec<T, A>,
+ len: usize,
+ additional: usize,
+ ) {
+ handle_reserve(slf.grow_amortized(len, additional));
+ }
+
+ if self.needs_to_grow(len, additional) {
+ do_reserve_and_handle(self, len, additional);
+ }
+ }
+
+ /// A specialized version of `reserve()` used only by the hot and
+ /// oft-instantiated `Vec::push()`, which does its own capacity check.
+ #[cfg(not(no_global_oom_handling))]
+ #[inline(never)]
+ pub fn reserve_for_push(&mut self, len: usize) {
+ handle_reserve(self.grow_amortized(len, 1));
+ }
+
+ /// The same as `reserve`, but returns on errors instead of panicking or aborting.
+ pub fn try_reserve(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
+ if self.needs_to_grow(len, additional) {
+ self.grow_amortized(len, additional)
+ } else {
+ Ok(())
+ }
+ }
+
+ /// Ensures that the buffer contains at least enough space to hold `len +
+ /// additional` elements. If it doesn't already, will reallocate the
+ /// minimum possible amount of memory necessary. Generally this will be
+ /// exactly the amount of memory necessary, but in principle the allocator
+ /// is free to give back more than we asked for.
+ ///
+ /// If `len` exceeds `self.capacity()`, this may fail to actually allocate
+ /// the requested space. This is not really unsafe, but the unsafe code
+ /// *you* write that relies on the behavior of this function may break.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Aborts
+ ///
+ /// Aborts on OOM.
+ #[cfg(not(no_global_oom_handling))]
+ pub fn reserve_exact(&mut self, len: usize, additional: usize) {
+ handle_reserve(self.try_reserve_exact(len, additional));
+ }
+
+ /// The same as `reserve_exact`, but returns on errors instead of panicking or aborting.
+ pub fn try_reserve_exact(
+ &mut self,
+ len: usize,
+ additional: usize,
+ ) -> Result<(), TryReserveError> {
+ if self.needs_to_grow(len, additional) { self.grow_exact(len, additional) } else { Ok(()) }
+ }
+
+ /// Shrinks the buffer down to the specified capacity. If the given amount
+ /// is 0, actually completely deallocates.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the given amount is *larger* than the current capacity.
+ ///
+ /// # Aborts
+ ///
+ /// Aborts on OOM.
+ #[cfg(not(no_global_oom_handling))]
+ pub fn shrink_to_fit(&mut self, cap: usize) {
+ handle_reserve(self.shrink(cap));
+ }
+}
+
+impl<T, A: Allocator> RawVec<T, A> {
+ /// Returns if the buffer needs to grow to fulfill the needed extra capacity.
+ /// Mainly used to make inlining reserve-calls possible without inlining `grow`.
+ fn needs_to_grow(&self, len: usize, additional: usize) -> bool {
+ additional > self.capacity().wrapping_sub(len)
+ }
+
+ fn set_ptr_and_cap(&mut self, ptr: NonNull<[u8]>, cap: usize) {
+ // Allocators currently return a `NonNull<[u8]>` whose length matches
+ // the size requested. If that ever changes, the capacity here should
+ // change to `ptr.len() / mem::size_of::<T>()`.
+ self.ptr = unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) };
+ self.cap = cap;
+ }
+
+ // This method is usually instantiated many times. So we want it to be as
+ // small as possible, to improve compile times. But we also want as much of
+ // its contents to be statically computable as possible, to make the
+ // generated code run faster. Therefore, this method is carefully written
+ // so that all of the code that depends on `T` is within it, while as much
+ // of the code that doesn't depend on `T` as possible is in functions that
+ // are non-generic over `T`.
+ fn grow_amortized(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
+ // This is ensured by the calling contexts.
+ debug_assert!(additional > 0);
+
+ if mem::size_of::<T>() == 0 {
+ // Since we return a capacity of `usize::MAX` when `elem_size` is
+ // 0, getting to here necessarily means the `RawVec` is overfull.
+ return Err(CapacityOverflow.into());
+ }
+
+ // Nothing we can really do about these checks, sadly.
+ let required_cap = len.checked_add(additional).ok_or(CapacityOverflow)?;
+
+ // This guarantees exponential growth. The doubling cannot overflow
+ // because `cap <= isize::MAX` and the type of `cap` is `usize`.
+ let cap = cmp::max(self.cap * 2, required_cap);
+ let cap = cmp::max(Self::MIN_NON_ZERO_CAP, cap);
+
+ let new_layout = Layout::array::<T>(cap);
+
+ // `finish_grow` is non-generic over `T`.
+ let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?;
+ self.set_ptr_and_cap(ptr, cap);
+ Ok(())
+ }
+
+ // The constraints on this method are much the same as those on
+ // `grow_amortized`, but this method is usually instantiated less often so
+ // it's less critical.
+ fn grow_exact(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
+ if mem::size_of::<T>() == 0 {
+ // Since we return a capacity of `usize::MAX` when the type size is
+ // 0, getting to here necessarily means the `RawVec` is overfull.
+ return Err(CapacityOverflow.into());
+ }
+
+ let cap = len.checked_add(additional).ok_or(CapacityOverflow)?;
+ let new_layout = Layout::array::<T>(cap);
+
+ // `finish_grow` is non-generic over `T`.
+ let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?;
+ self.set_ptr_and_cap(ptr, cap);
+ Ok(())
+ }
+
+ fn shrink(&mut self, cap: usize) -> Result<(), TryReserveError> {
+ assert!(cap <= self.capacity(), "Tried to shrink to a larger capacity");
+
+ let (ptr, layout) = if let Some(mem) = self.current_memory() { mem } else { return Ok(()) };
+ let new_size = cap * mem::size_of::<T>();
+
+ let ptr = unsafe {
+ let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
+ self.alloc
+ .shrink(ptr, layout, new_layout)
+ .map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
+ };
+ self.set_ptr_and_cap(ptr, cap);
+ Ok(())
+ }
+}
+
+// This function is outside `RawVec` to minimize compile times. See the comment
+// above `RawVec::grow_amortized` for details. (The `A` parameter isn't
+// significant, because the number of different `A` types seen in practice is
+// much smaller than the number of `T` types.)
+#[inline(never)]
+fn finish_grow<A>(
+ new_layout: Result<Layout, LayoutError>,
+ current_memory: Option<(NonNull<u8>, Layout)>,
+ alloc: &mut A,
+) -> Result<NonNull<[u8]>, TryReserveError>
+where
+ A: Allocator,
+{
+ // Check for the error here to minimize the size of `RawVec::grow_*`.
+ let new_layout = new_layout.map_err(|_| CapacityOverflow)?;
+
+ alloc_guard(new_layout.size())?;
+
+ let memory = if let Some((ptr, old_layout)) = current_memory {
+ debug_assert_eq!(old_layout.align(), new_layout.align());
+ unsafe {
+ // The allocator checks for alignment equality
+ intrinsics::assume(old_layout.align() == new_layout.align());
+ alloc.grow(ptr, old_layout, new_layout)
+ }
+ } else {
+ alloc.allocate(new_layout)
+ };
+
+ memory.map_err(|_| AllocError { layout: new_layout, non_exhaustive: () }.into())
+}
+
+unsafe impl<#[may_dangle] T, A: Allocator> Drop for RawVec<T, A> {
+ /// Frees the memory owned by the `RawVec` *without* trying to drop its contents.
+ fn drop(&mut self) {
+ if let Some((ptr, layout)) = self.current_memory() {
+ unsafe { self.alloc.deallocate(ptr, layout) }
+ }
+ }
+}
+
+// Central function for reserve error handling.
+#[cfg(not(no_global_oom_handling))]
+#[inline]
+fn handle_reserve(result: Result<(), TryReserveError>) {
+ match result.map_err(|e| e.kind()) {
+ Err(CapacityOverflow) => capacity_overflow(),
+ Err(AllocError { layout, .. }) => handle_alloc_error(layout),
+ Ok(()) => { /* yay */ }
+ }
+}
+
+// We need to guarantee the following:
+// * We don't ever allocate `> isize::MAX` byte-size objects.
+// * We don't overflow `usize::MAX` and actually allocate too little.
+//
+// On 64-bit we just need to check for overflow since trying to allocate
+// `> isize::MAX` bytes will surely fail. On 32-bit and 16-bit we need to add
+// an extra guard for this in case we're running on a platform which can use
+// all 4GB in user-space, e.g., PAE or x32.
+
+#[inline]
+fn alloc_guard(alloc_size: usize) -> Result<(), TryReserveError> {
+ if usize::BITS < 64 && alloc_size > isize::MAX as usize {
+ Err(CapacityOverflow.into())
+ } else {
+ Ok(())
+ }
+}
+
+// One central function responsible for reporting capacity overflows. This'll
+// ensure that the code generation related to these panics is minimal as there's
+// only one location which panics rather than a bunch throughout the module.
+#[cfg(not(no_global_oom_handling))]
+fn capacity_overflow() -> ! {
+ panic!("capacity overflow");
+}
diff --git a/rust/alloc/slice.rs b/rust/alloc/slice.rs
new file mode 100644
index 000000000000..f0397d08f95a
--- /dev/null
+++ b/rust/alloc/slice.rs
@@ -0,0 +1,1191 @@
+//! A dynamically-sized view into a contiguous sequence, `[T]`.
+//!
+//! *[See also the slice primitive type](slice).*
+//!
+//! Slices are a view into a block of memory represented as a pointer and a
+//! length.
+//!
+//! ```
+//! // slicing a Vec
+//! let vec = vec![1, 2, 3];
+//! let int_slice = &vec[..];
+//! // coercing an array to a slice
+//! let str_slice: &[&str] = &["one", "two", "three"];
+//! ```
+//!
+//! Slices are either mutable or shared. The shared slice type is `&[T]`,
+//! while the mutable slice type is `&mut [T]`, where `T` represents the element
+//! type. For example, you can mutate the block of memory that a mutable slice
+//! points to:
+//!
+//! ```
+//! let x = &mut [1, 2, 3];
+//! x[1] = 7;
+//! assert_eq!(x, &[1, 7, 3]);
+//! ```
+//!
+//! Here are some of the things this module contains:
+//!
+//! ## Structs
+//!
+//! There are several structs that are useful for slices, such as [`Iter`], which
+//! represents iteration over a slice.
+//!
+//! ## Trait Implementations
+//!
+//! There are several implementations of common traits for slices. Some examples
+//! include:
+//!
+//! * [`Clone`]
+//! * [`Eq`], [`Ord`] - for slices whose element type are [`Eq`] or [`Ord`].
+//! * [`Hash`] - for slices whose element type is [`Hash`].
+//!
+//! ## Iteration
+//!
+//! The slices implement `IntoIterator`. The iterator yields references to the
+//! slice elements.
+//!
+//! ```
+//! let numbers = &[0, 1, 2];
+//! for n in numbers {
+//! println!("{} is a number!", n);
+//! }
+//! ```
+//!
+//! The mutable slice yields mutable references to the elements:
+//!
+//! ```
+//! let mut scores = [7, 8, 9];
+//! for score in &mut scores[..] {
+//! *score += 1;
+//! }
+//! ```
+//!
+//! This iterator yields mutable references to the slice's elements, so while
+//! the element type of the slice is `i32`, the element type of the iterator is
+//! `&mut i32`.
+//!
+//! * [`.iter`] and [`.iter_mut`] are the explicit methods to return the default
+//! iterators.
+//! * Further methods that return iterators are [`.split`], [`.splitn`],
+//! [`.chunks`], [`.windows`] and more.
+//!
+//! [`Hash`]: core::hash::Hash
+//! [`.iter`]: slice::iter
+//! [`.iter_mut`]: slice::iter_mut
+//! [`.split`]: slice::split
+//! [`.splitn`]: slice::splitn
+//! [`.chunks`]: slice::chunks
+//! [`.windows`]: slice::windows
+#![stable(feature = "rust1", since = "1.0.0")]
+// Many of the usings in this module are only used in the test configuration.
+// It's cleaner to just turn off the unused_imports warning than to fix them.
+#![cfg_attr(test, allow(unused_imports, dead_code))]
+
+use core::borrow::{Borrow, BorrowMut};
+#[cfg(not(no_global_oom_handling))]
+use core::cmp::Ordering::{self, Less};
+#[cfg(not(no_global_oom_handling))]
+use core::mem;
+#[cfg(not(no_global_oom_handling))]
+use core::mem::size_of;
+#[cfg(not(no_global_oom_handling))]
+use core::ptr;
+
+use crate::alloc::Allocator;
+#[cfg(not(no_global_oom_handling))]
+use crate::alloc::Global;
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::vec::Vec;
+
+#[unstable(feature = "slice_range", issue = "76393")]
+pub use core::slice::range;
+#[unstable(feature = "array_chunks", issue = "74985")]
+pub use core::slice::ArrayChunks;
+#[unstable(feature = "array_chunks", issue = "74985")]
+pub use core::slice::ArrayChunksMut;
+#[unstable(feature = "array_windows", issue = "75027")]
+pub use core::slice::ArrayWindows;
+#[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
+pub use core::slice::EscapeAscii;
+#[stable(feature = "slice_get_slice", since = "1.28.0")]
+pub use core::slice::SliceIndex;
+#[stable(feature = "from_ref", since = "1.28.0")]
+pub use core::slice::{from_mut, from_ref};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{from_raw_parts, from_raw_parts_mut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{Chunks, Windows};
+#[stable(feature = "chunks_exact", since = "1.31.0")]
+pub use core::slice::{ChunksExact, ChunksExactMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{ChunksMut, Split, SplitMut};
+#[unstable(feature = "slice_group_by", issue = "80552")]
+pub use core::slice::{GroupBy, GroupByMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{Iter, IterMut};
+#[stable(feature = "rchunks", since = "1.31.0")]
+pub use core::slice::{RChunks, RChunksExact, RChunksExactMut, RChunksMut};
+#[stable(feature = "slice_rsplit", since = "1.27.0")]
+pub use core::slice::{RSplit, RSplitMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{RSplitN, RSplitNMut, SplitN, SplitNMut};
+#[stable(feature = "split_inclusive", since = "1.51.0")]
+pub use core::slice::{SplitInclusive, SplitInclusiveMut};
+
+////////////////////////////////////////////////////////////////////////////////
+// Basic slice extension methods
+////////////////////////////////////////////////////////////////////////////////
+
+// HACK(japaric) needed for the implementation of `vec!` macro during testing
+// N.B., see the `hack` module in this file for more details.
+#[cfg(test)]
+pub use hack::into_vec;
+
+// HACK(japaric) needed for the implementation of `Vec::clone` during testing
+// N.B., see the `hack` module in this file for more details.
+#[cfg(test)]
+pub use hack::to_vec;
+
+// HACK(japaric): With cfg(test) `impl [T]` is not available, these three
+// functions are actually methods that are in `impl [T]` but not in
+// `core::slice::SliceExt` - we need to supply these functions for the
+// `test_permutations` test
+mod hack {
+ use core::alloc::Allocator;
+
+ use crate::boxed::Box;
+ use crate::vec::Vec;
+
+ // We shouldn't add inline attribute to this since this is used in
+ // `vec!` macro mostly and causes perf regression. See #71204 for
+ // discussion and perf results.
+ pub fn into_vec<T, A: Allocator>(b: Box<[T], A>) -> Vec<T, A> {
+ unsafe {
+ let len = b.len();
+ let (b, alloc) = Box::into_raw_with_allocator(b);
+ Vec::from_raw_parts_in(b as *mut T, len, len, alloc)
+ }
+ }
+
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ pub fn to_vec<T: ConvertVec, A: Allocator>(s: &[T], alloc: A) -> Vec<T, A> {
+ T::to_vec(s, alloc)
+ }
+
+ #[cfg(not(no_global_oom_handling))]
+ pub trait ConvertVec {
+ fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A>
+ where
+ Self: Sized;
+ }
+
+ #[cfg(not(no_global_oom_handling))]
+ impl<T: Clone> ConvertVec for T {
+ #[inline]
+ default fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> {
+ struct DropGuard<'a, T, A: Allocator> {
+ vec: &'a mut Vec<T, A>,
+ num_init: usize,
+ }
+ impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> {
+ #[inline]
+ fn drop(&mut self) {
+ // SAFETY:
+ // items were marked initialized in the loop below
+ unsafe {
+ self.vec.set_len(self.num_init);
+ }
+ }
+ }
+ let mut vec = Vec::with_capacity_in(s.len(), alloc);
+ let mut guard = DropGuard { vec: &mut vec, num_init: 0 };
+ let slots = guard.vec.spare_capacity_mut();
+ // .take(slots.len()) is necessary for LLVM to remove bounds checks
+ // and has better codegen than zip.
+ for (i, b) in s.iter().enumerate().take(slots.len()) {
+ guard.num_init = i;
+ slots[i].write(b.clone());
+ }
+ core::mem::forget(guard);
+ // SAFETY:
+ // the vec was allocated and initialized above to at least this length.
+ unsafe {
+ vec.set_len(s.len());
+ }
+ vec
+ }
+ }
+
+ #[cfg(not(no_global_oom_handling))]
+ impl<T: Copy> ConvertVec for T {
+ #[inline]
+ fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> {
+ let mut v = Vec::with_capacity_in(s.len(), alloc);
+ // SAFETY:
+ // allocated above with the capacity of `s`, and initialize to `s.len()` in
+ // ptr::copy_to_non_overlapping below.
+ unsafe {
+ s.as_ptr().copy_to_nonoverlapping(v.as_mut_ptr(), s.len());
+ v.set_len(s.len());
+ }
+ v
+ }
+ }
+}
+
+#[lang = "slice_alloc"]
+#[cfg(not(test))]
+impl<T> [T] {
+ /// Sorts the slice.
+ ///
+ /// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case.
+ ///
+ /// When applicable, unstable sorting is preferred because it is generally faster than stable
+ /// sorting and it doesn't allocate auxiliary memory.
+ /// See [`sort_unstable`](slice::sort_unstable).
+ ///
+ /// # Current implementation
+ ///
+ /// The current algorithm is an adaptive, iterative merge sort inspired by
+ /// [timsort](https://en.wikipedia.org/wiki/Timsort).
+ /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
+ /// two or more sorted sequences concatenated one after another.
+ ///
+ /// Also, it allocates temporary storage half the size of `self`, but for short slices a
+ /// non-allocating insertion sort is used instead.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = [-5, 4, 1, -3, 2];
+ ///
+ /// v.sort();
+ /// assert!(v == [-5, -3, 1, 2, 4]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[inline]
+ pub fn sort(&mut self)
+ where
+ T: Ord,
+ {
+ merge_sort(self, |a, b| a.lt(b));
+ }
+
+ /// Sorts the slice with a comparator function.
+ ///
+ /// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case.
+ ///
+ /// The comparator function must define a total ordering for the elements in the slice. If
+ /// the ordering is not total, the order of the elements is unspecified. An order is a
+ /// total order if it is (for all `a`, `b` and `c`):
+ ///
+ /// * total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and
+ /// * transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.
+ ///
+ /// For example, while [`f64`] doesn't implement [`Ord`] because `NaN != NaN`, we can use
+ /// `partial_cmp` as our sort function when we know the slice doesn't contain a `NaN`.
+ ///
+ /// ```
+ /// let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
+ /// floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
+ /// assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);
+ /// ```
+ ///
+ /// When applicable, unstable sorting is preferred because it is generally faster than stable
+ /// sorting and it doesn't allocate auxiliary memory.
+ /// See [`sort_unstable_by`](slice::sort_unstable_by).
+ ///
+ /// # Current implementation
+ ///
+ /// The current algorithm is an adaptive, iterative merge sort inspired by
+ /// [timsort](https://en.wikipedia.org/wiki/Timsort).
+ /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
+ /// two or more sorted sequences concatenated one after another.
+ ///
+ /// Also, it allocates temporary storage half the size of `self`, but for short slices a
+ /// non-allocating insertion sort is used instead.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = [5, 4, 1, 3, 2];
+ /// v.sort_by(|a, b| a.cmp(b));
+ /// assert!(v == [1, 2, 3, 4, 5]);
+ ///
+ /// // reverse sorting
+ /// v.sort_by(|a, b| b.cmp(a));
+ /// assert!(v == [5, 4, 3, 2, 1]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[inline]
+ pub fn sort_by<F>(&mut self, mut compare: F)
+ where
+ F: FnMut(&T, &T) -> Ordering,
+ {
+ merge_sort(self, |a, b| compare(a, b) == Less);
+ }
+
+ /// Sorts the slice with a key extraction function.
+ ///
+ /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* \* log(*n*))
+ /// worst-case, where the key function is *O*(*m*).
+ ///
+ /// For expensive key functions (e.g. functions that are not simple property accesses or
+ /// basic operations), [`sort_by_cached_key`](slice::sort_by_cached_key) is likely to be
+ /// significantly faster, as it does not recompute element keys.
+ ///
+ /// When applicable, unstable sorting is preferred because it is generally faster than stable
+ /// sorting and it doesn't allocate auxiliary memory.
+ /// See [`sort_unstable_by_key`](slice::sort_unstable_by_key).
+ ///
+ /// # Current implementation
+ ///
+ /// The current algorithm is an adaptive, iterative merge sort inspired by
+ /// [timsort](https://en.wikipedia.org/wiki/Timsort).
+ /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
+ /// two or more sorted sequences concatenated one after another.
+ ///
+ /// Also, it allocates temporary storage half the size of `self`, but for short slices a
+ /// non-allocating insertion sort is used instead.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = [-5i32, 4, 1, -3, 2];
+ ///
+ /// v.sort_by_key(|k| k.abs());
+ /// assert!(v == [1, 2, -3, 4, -5]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "slice_sort_by_key", since = "1.7.0")]
+ #[inline]
+ pub fn sort_by_key<K, F>(&mut self, mut f: F)
+ where
+ F: FnMut(&T) -> K,
+ K: Ord,
+ {
+ merge_sort(self, |a, b| f(a).lt(&f(b)));
+ }
+
+ /// Sorts the slice with a key extraction function.
+ ///
+ /// During sorting, the key function is called at most once per element, by using
+ /// temporary storage to remember the results of key evaluation.
+ /// The order of calls to the key function is unspecified and may change in future versions
+ /// of the standard library.
+ ///
+ /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* + *n* \* log(*n*))
+ /// worst-case, where the key function is *O*(*m*).
+ ///
+ /// For simple key functions (e.g., functions that are property accesses or
+ /// basic operations), [`sort_by_key`](slice::sort_by_key) is likely to be
+ /// faster.
+ ///
+ /// # Current implementation
+ ///
+ /// The current algorithm is based on [pattern-defeating quicksort][pdqsort] by Orson Peters,
+ /// which combines the fast average case of randomized quicksort with the fast worst case of
+ /// heapsort, while achieving linear time on slices with certain patterns. It uses some
+ /// randomization to avoid degenerate cases, but with a fixed seed to always provide
+ /// deterministic behavior.
+ ///
+ /// In the worst case, the algorithm allocates temporary storage in a `Vec<(K, usize)>` the
+ /// length of the slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = [-5i32, 4, 32, -3, 2];
+ ///
+ /// v.sort_by_cached_key(|k| k.to_string());
+ /// assert!(v == [-3, -5, 2, 32, 4]);
+ /// ```
+ ///
+ /// [pdqsort]: https://github.com/orlp/pdqsort
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "slice_sort_by_cached_key", since = "1.34.0")]
+ #[inline]
+ pub fn sort_by_cached_key<K, F>(&mut self, f: F)
+ where
+ F: FnMut(&T) -> K,
+ K: Ord,
+ {
+ // Helper macro for indexing our vector by the smallest possible type, to reduce allocation.
+ macro_rules! sort_by_key {
+ ($t:ty, $slice:ident, $f:ident) => {{
+ let mut indices: Vec<_> =
+ $slice.iter().map($f).enumerate().map(|(i, k)| (k, i as $t)).collect();
+ // The elements of `indices` are unique, as they are indexed, so any sort will be
+ // stable with respect to the original slice. We use `sort_unstable` here because
+ // it requires less memory allocation.
+ indices.sort_unstable();
+ for i in 0..$slice.len() {
+ let mut index = indices[i].1;
+ while (index as usize) < i {
+ index = indices[index as usize].1;
+ }
+ indices[i].1 = index;
+ $slice.swap(i, index as usize);
+ }
+ }};
+ }
+
+ let sz_u8 = mem::size_of::<(K, u8)>();
+ let sz_u16 = mem::size_of::<(K, u16)>();
+ let sz_u32 = mem::size_of::<(K, u32)>();
+ let sz_usize = mem::size_of::<(K, usize)>();
+
+ let len = self.len();
+ if len < 2 {
+ return;
+ }
+ if sz_u8 < sz_u16 && len <= (u8::MAX as usize) {
+ return sort_by_key!(u8, self, f);
+ }
+ if sz_u16 < sz_u32 && len <= (u16::MAX as usize) {
+ return sort_by_key!(u16, self, f);
+ }
+ if sz_u32 < sz_usize && len <= (u32::MAX as usize) {
+ return sort_by_key!(u32, self, f);
+ }
+ sort_by_key!(usize, self, f)
+ }
+
+ /// Copies `self` into a new `Vec`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let s = [10, 40, 30];
+ /// let x = s.to_vec();
+ /// // Here, `s` and `x` can be modified independently.
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[rustc_conversion_suggestion]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[inline]
+ pub fn to_vec(&self) -> Vec<T>
+ where
+ T: Clone,
+ {
+ self.to_vec_in(Global)
+ }
+
+ /// Copies `self` into a new `Vec` with an allocator.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let s = [10, 40, 30];
+ /// let x = s.to_vec_in(System);
+ /// // Here, `s` and `x` can be modified independently.
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ pub fn to_vec_in<A: Allocator>(&self, alloc: A) -> Vec<T, A>
+ where
+ T: Clone,
+ {
+ // N.B., see the `hack` module in this file for more details.
+ hack::to_vec(self, alloc)
+ }
+
+ /// Converts `self` into a vector without clones or allocation.
+ ///
+ /// The resulting vector can be converted back into a box via
+ /// `Vec<T>`'s `into_boxed_slice` method.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let s: Box<[i32]> = Box::new([10, 40, 30]);
+ /// let x = s.into_vec();
+ /// // `s` cannot be used anymore because it has been converted into `x`.
+ ///
+ /// assert_eq!(x, vec![10, 40, 30]);
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[inline]
+ pub fn into_vec<A: Allocator>(self: Box<Self, A>) -> Vec<T, A> {
+ // N.B., see the `hack` module in this file for more details.
+ hack::into_vec(self)
+ }
+
+ /// Creates a vector by repeating a slice `n` times.
+ ///
+ /// # Panics
+ ///
+ /// This function will panic if the capacity would overflow.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
+ /// ```
+ ///
+ /// A panic upon overflow:
+ ///
+ /// ```should_panic
+ /// // this will panic at runtime
+ /// b"0123456789abcdef".repeat(usize::MAX);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "repeat_generic_slice", since = "1.40.0")]
+ pub fn repeat(&self, n: usize) -> Vec<T>
+ where
+ T: Copy,
+ {
+ if n == 0 {
+ return Vec::new();
+ }
+
+ // If `n` is larger than zero, it can be split as
+ // `n = 2^expn + rem (2^expn > rem, expn >= 0, rem >= 0)`.
+ // `2^expn` is the number represented by the leftmost '1' bit of `n`,
+ // and `rem` is the remaining part of `n`.
+
+ // Using `Vec` to access `set_len()`.
+ let capacity = self.len().checked_mul(n).expect("capacity overflow");
+ let mut buf = Vec::with_capacity(capacity);
+
+ // `2^expn` repetition is done by doubling `buf` `expn`-times.
+ buf.extend(self);
+ {
+ let mut m = n >> 1;
+ // If `m > 0`, there are remaining bits up to the leftmost '1'.
+ while m > 0 {
+ // `buf.extend(buf)`:
+ unsafe {
+ ptr::copy_nonoverlapping(
+ buf.as_ptr(),
+ (buf.as_mut_ptr() as *mut T).add(buf.len()),
+ buf.len(),
+ );
+ // `buf` has capacity of `self.len() * n`.
+ let buf_len = buf.len();
+ buf.set_len(buf_len * 2);
+ }
+
+ m >>= 1;
+ }
+ }
+
+ // `rem` (`= n - 2^expn`) repetition is done by copying
+ // first `rem` repetitions from `buf` itself.
+ let rem_len = capacity - buf.len(); // `self.len() * rem`
+ if rem_len > 0 {
+ // `buf.extend(buf[0 .. rem_len])`:
+ unsafe {
+ // This is non-overlapping since `2^expn > rem`.
+ ptr::copy_nonoverlapping(
+ buf.as_ptr(),
+ (buf.as_mut_ptr() as *mut T).add(buf.len()),
+ rem_len,
+ );
+ // `buf.len() + rem_len` equals to `buf.capacity()` (`= self.len() * n`).
+ buf.set_len(capacity);
+ }
+ }
+ buf
+ }
+
+ /// Flattens a slice of `T` into a single value `Self::Output`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(["hello", "world"].concat(), "helloworld");
+ /// assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn concat<Item: ?Sized>(&self) -> <Self as Concat<Item>>::Output
+ where
+ Self: Concat<Item>,
+ {
+ Concat::concat(self)
+ }
+
+ /// Flattens a slice of `T` into a single value `Self::Output`, placing a
+ /// given separator between each.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(["hello", "world"].join(" "), "hello world");
+ /// assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
+ /// assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
+ /// ```
+ #[stable(feature = "rename_connect_to_join", since = "1.3.0")]
+ pub fn join<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
+ where
+ Self: Join<Separator>,
+ {
+ Join::join(self, sep)
+ }
+
+ /// Flattens a slice of `T` into a single value `Self::Output`, placing a
+ /// given separator between each.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # #![allow(deprecated)]
+ /// assert_eq!(["hello", "world"].connect(" "), "hello world");
+ /// assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[rustc_deprecated(since = "1.3.0", reason = "renamed to join")]
+ pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
+ where
+ Self: Join<Separator>,
+ {
+ Join::join(self, sep)
+ }
+}
+
+#[lang = "slice_u8_alloc"]
+#[cfg(not(test))]
+impl [u8] {
+ /// Returns a vector containing a copy of this slice where each byte
+ /// is mapped to its ASCII upper case equivalent.
+ ///
+ /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+ /// but non-ASCII letters are unchanged.
+ ///
+ /// To uppercase the value in-place, use [`make_ascii_uppercase`].
+ ///
+ /// [`make_ascii_uppercase`]: slice::make_ascii_uppercase
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "this returns the uppercase bytes as a new Vec, \
+ without modifying the original"]
+ #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+ #[inline]
+ pub fn to_ascii_uppercase(&self) -> Vec<u8> {
+ let mut me = self.to_vec();
+ me.make_ascii_uppercase();
+ me
+ }
+
+ /// Returns a vector containing a copy of this slice where each byte
+ /// is mapped to its ASCII lower case equivalent.
+ ///
+ /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+ /// but non-ASCII letters are unchanged.
+ ///
+ /// To lowercase the value in-place, use [`make_ascii_lowercase`].
+ ///
+ /// [`make_ascii_lowercase`]: slice::make_ascii_lowercase
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "this returns the lowercase bytes as a new Vec, \
+ without modifying the original"]
+ #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+ #[inline]
+ pub fn to_ascii_lowercase(&self) -> Vec<u8> {
+ let mut me = self.to_vec();
+ me.make_ascii_lowercase();
+ me
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Extension traits for slices over specific kinds of data
+////////////////////////////////////////////////////////////////////////////////
+
+/// Helper trait for [`[T]::concat`](slice::concat).
+///
+/// Note: the `Item` type parameter is not used in this trait,
+/// but it allows impls to be more generic.
+/// Without it, we get this error:
+///
+/// ```error
+/// error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predica
+/// --> src/liballoc/slice.rs:608:6
+/// |
+/// 608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] {
+/// | ^ unconstrained type parameter
+/// ```
+///
+/// This is because there could exist `V` types with multiple `Borrow<[_]>` impls,
+/// such that multiple `T` types would apply:
+///
+/// ```
+/// # #[allow(dead_code)]
+/// pub struct Foo(Vec<u32>, Vec<String>);
+///
+/// impl std::borrow::Borrow<[u32]> for Foo {
+/// fn borrow(&self) -> &[u32] { &self.0 }
+/// }
+///
+/// impl std::borrow::Borrow<[String]> for Foo {
+/// fn borrow(&self) -> &[String] { &self.1 }
+/// }
+/// ```
+#[unstable(feature = "slice_concat_trait", issue = "27747")]
+pub trait Concat<Item: ?Sized> {
+ #[unstable(feature = "slice_concat_trait", issue = "27747")]
+ /// The resulting type after concatenation
+ type Output;
+
+ /// Implementation of [`[T]::concat`](slice::concat)
+ #[unstable(feature = "slice_concat_trait", issue = "27747")]
+ fn concat(slice: &Self) -> Self::Output;
+}
+
+/// Helper trait for [`[T]::join`](slice::join)
+#[unstable(feature = "slice_concat_trait", issue = "27747")]
+pub trait Join<Separator> {
+ #[unstable(feature = "slice_concat_trait", issue = "27747")]
+ /// The resulting type after concatenation
+ type Output;
+
+ /// Implementation of [`[T]::join`](slice::join)
+ #[unstable(feature = "slice_concat_trait", issue = "27747")]
+ fn join(slice: &Self, sep: Separator) -> Self::Output;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Concat<T> for [V] {
+ type Output = Vec<T>;
+
+ fn concat(slice: &Self) -> Vec<T> {
+ let size = slice.iter().map(|slice| slice.borrow().len()).sum();
+ let mut result = Vec::with_capacity(size);
+ for v in slice {
+ result.extend_from_slice(v.borrow())
+ }
+ result
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Join<&T> for [V] {
+ type Output = Vec<T>;
+
+ fn join(slice: &Self, sep: &T) -> Vec<T> {
+ let mut iter = slice.iter();
+ let first = match iter.next() {
+ Some(first) => first,
+ None => return vec![],
+ };
+ let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() + slice.len() - 1;
+ let mut result = Vec::with_capacity(size);
+ result.extend_from_slice(first.borrow());
+
+ for v in iter {
+ result.push(sep.clone());
+ result.extend_from_slice(v.borrow())
+ }
+ result
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Join<&[T]> for [V] {
+ type Output = Vec<T>;
+
+ fn join(slice: &Self, sep: &[T]) -> Vec<T> {
+ let mut iter = slice.iter();
+ let first = match iter.next() {
+ Some(first) => first,
+ None => return vec![],
+ };
+ let size =
+ slice.iter().map(|v| v.borrow().len()).sum::<usize>() + sep.len() * (slice.len() - 1);
+ let mut result = Vec::with_capacity(size);
+ result.extend_from_slice(first.borrow());
+
+ for v in iter {
+ result.extend_from_slice(sep);
+ result.extend_from_slice(v.borrow())
+ }
+ result
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Standard trait implementations for slices
+////////////////////////////////////////////////////////////////////////////////
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Borrow<[T]> for Vec<T> {
+ fn borrow(&self) -> &[T] {
+ &self[..]
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BorrowMut<[T]> for Vec<T> {
+ fn borrow_mut(&mut self) -> &mut [T] {
+ &mut self[..]
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone> ToOwned for [T] {
+ type Owned = Vec<T>;
+ #[cfg(not(test))]
+ fn to_owned(&self) -> Vec<T> {
+ self.to_vec()
+ }
+
+ #[cfg(test)]
+ fn to_owned(&self) -> Vec<T> {
+ hack::to_vec(self, Global)
+ }
+
+ fn clone_into(&self, target: &mut Vec<T>) {
+ // drop anything in target that will not be overwritten
+ target.truncate(self.len());
+
+ // target.len <= self.len due to the truncate above, so the
+ // slices here are always in-bounds.
+ let (init, tail) = self.split_at(target.len());
+
+ // reuse the contained values' allocations/resources.
+ target.clone_from_slice(init);
+ target.extend_from_slice(tail);
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Sorting
+////////////////////////////////////////////////////////////////////////////////
+
+/// Inserts `v[0]` into pre-sorted sequence `v[1..]` so that whole `v[..]` becomes sorted.
+///
+/// This is the integral subroutine of insertion sort.
+#[cfg(not(no_global_oom_handling))]
+fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
+where
+ F: FnMut(&T, &T) -> bool,
+{
+ if v.len() >= 2 && is_less(&v[1], &v[0]) {
+ unsafe {
+ // There are three ways to implement insertion here:
+ //
+ // 1. Swap adjacent elements until the first one gets to its final destination.
+ // However, this way we copy data around more than is necessary. If elements are big
+ // structures (costly to copy), this method will be slow.
+ //
+ // 2. Iterate until the right place for the first element is found. Then shift the
+ // elements succeeding it to make room for it and finally place it into the
+ // remaining hole. This is a good method.
+ //
+ // 3. Copy the first element into a temporary variable. Iterate until the right place
+ // for it is found. As we go along, copy every traversed element into the slot
+ // preceding it. Finally, copy data from the temporary variable into the remaining
+ // hole. This method is very good. Benchmarks demonstrated slightly better
+ // performance than with the 2nd method.
+ //
+ // All methods were benchmarked, and the 3rd showed best results. So we chose that one.
+ let tmp = mem::ManuallyDrop::new(ptr::read(&v[0]));
+
+ // Intermediate state of the insertion process is always tracked by `hole`, which
+ // serves two purposes:
+ // 1. Protects integrity of `v` from panics in `is_less`.
+ // 2. Fills the remaining hole in `v` in the end.
+ //
+ // Panic safety:
+ //
+ // If `is_less` panics at any point during the process, `hole` will get dropped and
+ // fill the hole in `v` with `tmp`, thus ensuring that `v` still holds every object it
+ // initially held exactly once.
+ let mut hole = InsertionHole { src: &*tmp, dest: &mut v[1] };
+ ptr::copy_nonoverlapping(&v[1], &mut v[0], 1);
+
+ for i in 2..v.len() {
+ if !is_less(&v[i], &*tmp) {
+ break;
+ }
+ ptr::copy_nonoverlapping(&v[i], &mut v[i - 1], 1);
+ hole.dest = &mut v[i];
+ }
+ // `hole` gets dropped and thus copies `tmp` into the remaining hole in `v`.
+ }
+ }
+
+ // When dropped, copies from `src` into `dest`.
+ struct InsertionHole<T> {
+ src: *const T,
+ dest: *mut T,
+ }
+
+ impl<T> Drop for InsertionHole<T> {
+ fn drop(&mut self) {
+ unsafe {
+ ptr::copy_nonoverlapping(self.src, self.dest, 1);
+ }
+ }
+ }
+}
+
+/// Merges non-decreasing runs `v[..mid]` and `v[mid..]` using `buf` as temporary storage, and
+/// stores the result into `v[..]`.
+///
+/// # Safety
+///
+/// The two slices must be non-empty and `mid` must be in bounds. Buffer `buf` must be long enough
+/// to hold a copy of the shorter slice. Also, `T` must not be a zero-sized type.
+#[cfg(not(no_global_oom_handling))]
+unsafe fn merge<T, F>(v: &mut [T], mid: usize, buf: *mut T, is_less: &mut F)
+where
+ F: FnMut(&T, &T) -> bool,
+{
+ let len = v.len();
+ let v = v.as_mut_ptr();
+ let (v_mid, v_end) = unsafe { (v.add(mid), v.add(len)) };
+
+ // The merge process first copies the shorter run into `buf`. Then it traces the newly copied
+ // run and the longer run forwards (or backwards), comparing their next unconsumed elements and
+ // copying the lesser (or greater) one into `v`.
+ //
+ // As soon as the shorter run is fully consumed, the process is done. If the longer run gets
+ // consumed first, then we must copy whatever is left of the shorter run into the remaining
+ // hole in `v`.
+ //
+ // Intermediate state of the process is always tracked by `hole`, which serves two purposes:
+ // 1. Protects integrity of `v` from panics in `is_less`.
+ // 2. Fills the remaining hole in `v` if the longer run gets consumed first.
+ //
+ // Panic safety:
+ //
+ // If `is_less` panics at any point during the process, `hole` will get dropped and fill the
+ // hole in `v` with the unconsumed range in `buf`, thus ensuring that `v` still holds every
+ // object it initially held exactly once.
+ let mut hole;
+
+ if mid <= len - mid {
+ // The left run is shorter.
+ unsafe {
+ ptr::copy_nonoverlapping(v, buf, mid);
+ hole = MergeHole { start: buf, end: buf.add(mid), dest: v };
+ }
+
+ // Initially, these pointers point to the beginnings of their arrays.
+ let left = &mut hole.start;
+ let mut right = v_mid;
+ let out = &mut hole.dest;
+
+ while *left < hole.end && right < v_end {
+ // Consume the lesser side.
+ // If equal, prefer the left run to maintain stability.
+ unsafe {
+ let to_copy = if is_less(&*right, &**left) {
+ get_and_increment(&mut right)
+ } else {
+ get_and_increment(left)
+ };
+ ptr::copy_nonoverlapping(to_copy, get_and_increment(out), 1);
+ }
+ }
+ } else {
+ // The right run is shorter.
+ unsafe {
+ ptr::copy_nonoverlapping(v_mid, buf, len - mid);
+ hole = MergeHole { start: buf, end: buf.add(len - mid), dest: v_mid };
+ }
+
+ // Initially, these pointers point past the ends of their arrays.
+ let left = &mut hole.dest;
+ let right = &mut hole.end;
+ let mut out = v_end;
+
+ while v < *left && buf < *right {
+ // Consume the greater side.
+ // If equal, prefer the right run to maintain stability.
+ unsafe {
+ let to_copy = if is_less(&*right.offset(-1), &*left.offset(-1)) {
+ decrement_and_get(left)
+ } else {
+ decrement_and_get(right)
+ };
+ ptr::copy_nonoverlapping(to_copy, decrement_and_get(&mut out), 1);
+ }
+ }
+ }
+ // Finally, `hole` gets dropped. If the shorter run was not fully consumed, whatever remains of
+ // it will now be copied into the hole in `v`.
+
+ unsafe fn get_and_increment<T>(ptr: &mut *mut T) -> *mut T {
+ let old = *ptr;
+ *ptr = unsafe { ptr.offset(1) };
+ old
+ }
+
+ unsafe fn decrement_and_get<T>(ptr: &mut *mut T) -> *mut T {
+ *ptr = unsafe { ptr.offset(-1) };
+ *ptr
+ }
+
+ // When dropped, copies the range `start..end` into `dest..`.
+ struct MergeHole<T> {
+ start: *mut T,
+ end: *mut T,
+ dest: *mut T,
+ }
+
+ impl<T> Drop for MergeHole<T> {
+ fn drop(&mut self) {
+ // `T` is not a zero-sized type, so it's okay to divide by its size.
+ let len = (self.end as usize - self.start as usize) / mem::size_of::<T>();
+ unsafe {
+ ptr::copy_nonoverlapping(self.start, self.dest, len);
+ }
+ }
+ }
+}
+
+/// This merge sort borrows some (but not all) ideas from TimSort, which is described in detail
+/// [here](https://github.com/python/cpython/blob/main/Objects/listsort.txt).
+///
+/// The algorithm identifies strictly descending and non-descending subsequences, which are called
+/// natural runs. There is a stack of pending runs yet to be merged. Each newly found run is pushed
+/// onto the stack, and then some pairs of adjacent runs are merged until these two invariants are
+/// satisfied:
+///
+/// 1. for every `i` in `1..runs.len()`: `runs[i - 1].len > runs[i].len`
+/// 2. for every `i` in `2..runs.len()`: `runs[i - 2].len > runs[i - 1].len + runs[i].len`
+///
+/// The invariants ensure that the total running time is *O*(*n* \* log(*n*)) worst-case.
+#[cfg(not(no_global_oom_handling))]
+fn merge_sort<T, F>(v: &mut [T], mut is_less: F)
+where
+ F: FnMut(&T, &T) -> bool,
+{
+ // Slices of up to this length get sorted using insertion sort.
+ const MAX_INSERTION: usize = 20;
+ // Very short runs are extended using insertion sort to span at least this many elements.
+ const MIN_RUN: usize = 10;
+
+ // Sorting has no meaningful behavior on zero-sized types.
+ if size_of::<T>() == 0 {
+ return;
+ }
+
+ let len = v.len();
+
+ // Short arrays get sorted in-place via insertion sort to avoid allocations.
+ if len <= MAX_INSERTION {
+ if len >= 2 {
+ for i in (0..len - 1).rev() {
+ insert_head(&mut v[i..], &mut is_less);
+ }
+ }
+ return;
+ }
+
+ // Allocate a buffer to use as scratch memory. We keep the length 0 so we can keep in it
+ // shallow copies of the contents of `v` without risking the dtors running on copies if
+ // `is_less` panics. When merging two sorted runs, this buffer holds a copy of the shorter run,
+ // which will always have length at most `len / 2`.
+ let mut buf = Vec::with_capacity(len / 2);
+
+ // In order to identify natural runs in `v`, we traverse it backwards. That might seem like a
+ // strange decision, but consider the fact that merges more often go in the opposite direction
+ // (forwards). According to benchmarks, merging forwards is slightly faster than merging
+ // backwards. To conclude, identifying runs by traversing backwards improves performance.
+ let mut runs = vec![];
+ let mut end = len;
+ while end > 0 {
+ // Find the next natural run, and reverse it if it's strictly descending.
+ let mut start = end - 1;
+ if start > 0 {
+ start -= 1;
+ unsafe {
+ if is_less(v.get_unchecked(start + 1), v.get_unchecked(start)) {
+ while start > 0 && is_less(v.get_unchecked(start), v.get_unchecked(start - 1)) {
+ start -= 1;
+ }
+ v[start..end].reverse();
+ } else {
+ while start > 0 && !is_less(v.get_unchecked(start), v.get_unchecked(start - 1))
+ {
+ start -= 1;
+ }
+ }
+ }
+ }
+
+ // Insert some more elements into the run if it's too short. Insertion sort is faster than
+ // merge sort on short sequences, so this significantly improves performance.
+ while start > 0 && end - start < MIN_RUN {
+ start -= 1;
+ insert_head(&mut v[start..end], &mut is_less);
+ }
+
+ // Push this run onto the stack.
+ runs.push(Run { start, len: end - start });
+ end = start;
+
+ // Merge some pairs of adjacent runs to satisfy the invariants.
+ while let Some(r) = collapse(&runs) {
+ let left = runs[r + 1];
+ let right = runs[r];
+ unsafe {
+ merge(
+ &mut v[left.start..right.start + right.len],
+ left.len,
+ buf.as_mut_ptr(),
+ &mut is_less,
+ );
+ }
+ runs[r] = Run { start: left.start, len: left.len + right.len };
+ runs.remove(r + 1);
+ }
+ }
+
+ // Finally, exactly one run must remain in the stack.
+ debug_assert!(runs.len() == 1 && runs[0].start == 0 && runs[0].len == len);
+
+ // Examines the stack of runs and identifies the next pair of runs to merge. More specifically,
+ // if `Some(r)` is returned, that means `runs[r]` and `runs[r + 1]` must be merged next. If the
+ // algorithm should continue building a new run instead, `None` is returned.
+ //
+ // TimSort is infamous for its buggy implementations, as described here:
+ // http://envisage-project.eu/timsort-specification-and-verification/
+ //
+ // The gist of the story is: we must enforce the invariants on the top four runs on the stack.
+ // Enforcing them on just top three is not sufficient to ensure that the invariants will still
+ // hold for *all* runs in the stack.
+ //
+ // This function correctly checks invariants for the top four runs. Additionally, if the top
+ // run starts at index 0, it will always demand a merge operation until the stack is fully
+ // collapsed, in order to complete the sort.
+ #[inline]
+ fn collapse(runs: &[Run]) -> Option<usize> {
+ let n = runs.len();
+ if n >= 2
+ && (runs[n - 1].start == 0
+ || runs[n - 2].len <= runs[n - 1].len
+ || (n >= 3 && runs[n - 3].len <= runs[n - 2].len + runs[n - 1].len)
+ || (n >= 4 && runs[n - 4].len <= runs[n - 3].len + runs[n - 2].len))
+ {
+ if n >= 3 && runs[n - 3].len < runs[n - 1].len { Some(n - 3) } else { Some(n - 2) }
+ } else {
+ None
+ }
+ }
+
+ #[derive(Clone, Copy)]
+ struct Run {
+ start: usize,
+ len: usize,
+ }
+}
diff --git a/rust/alloc/str.rs b/rust/alloc/str.rs
new file mode 100644
index 000000000000..69495f31c32c
--- /dev/null
+++ b/rust/alloc/str.rs
@@ -0,0 +1,613 @@
+//! Unicode string slices.
+//!
+//! *[See also the `str` primitive type](str).*
+//!
+//! The `&str` type is one of the two main string types, the other being `String`.
+//! Unlike its `String` counterpart, its contents are borrowed.
+//!
+//! # Basic Usage
+//!
+//! A basic string declaration of `&str` type:
+//!
+//! ```
+//! let hello_world = "Hello, World!";
+//! ```
+//!
+//! Here we have declared a string literal, also known as a string slice.
+//! String literals have a static lifetime, which means the string `hello_world`
+//! is guaranteed to be valid for the duration of the entire program.
+//! We can explicitly specify `hello_world`'s lifetime as well:
+//!
+//! ```
+//! let hello_world: &'static str = "Hello, world!";
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+// Many of the usings in this module are only used in the test configuration.
+// It's cleaner to just turn off the unused_imports warning than to fix them.
+#![allow(unused_imports)]
+
+use core::borrow::{Borrow, BorrowMut};
+use core::iter::FusedIterator;
+use core::mem;
+use core::ptr;
+use core::str::pattern::{DoubleEndedSearcher, Pattern, ReverseSearcher, Searcher};
+use core::unicode::conversions;
+
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::slice::{Concat, Join, SliceIndex};
+use crate::string::String;
+use crate::vec::Vec;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::pattern;
+#[stable(feature = "encode_utf16", since = "1.8.0")]
+pub use core::str::EncodeUtf16;
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
+pub use core::str::SplitAsciiWhitespace;
+#[stable(feature = "split_inclusive", since = "1.51.0")]
+pub use core::str::SplitInclusive;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::SplitWhitespace;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{from_utf8, from_utf8_mut, Bytes, CharIndices, Chars};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{from_utf8_unchecked, from_utf8_unchecked_mut, ParseBoolError};
+#[stable(feature = "str_escape", since = "1.34.0")]
+pub use core::str::{EscapeDebug, EscapeDefault, EscapeUnicode};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{FromStr, Utf8Error};
+#[allow(deprecated)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{Lines, LinesAny};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{MatchIndices, RMatchIndices};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{Matches, RMatches};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{RSplit, Split};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{RSplitN, SplitN};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{RSplitTerminator, SplitTerminator};
+
+/// Note: `str` in `Concat<str>` is not meaningful here.
+/// This type parameter of the trait only exists to enable another impl.
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<S: Borrow<str>> Concat<str> for [S] {
+ type Output = String;
+
+ fn concat(slice: &Self) -> String {
+ Join::join(slice, "")
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<S: Borrow<str>> Join<&str> for [S] {
+ type Output = String;
+
+ fn join(slice: &Self, sep: &str) -> String {
+ unsafe { String::from_utf8_unchecked(join_generic_copy(slice, sep.as_bytes())) }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+macro_rules! specialize_for_lengths {
+ ($separator:expr, $target:expr, $iter:expr; $($num:expr),*) => {{
+ let mut target = $target;
+ let iter = $iter;
+ let sep_bytes = $separator;
+ match $separator.len() {
+ $(
+ // loops with hardcoded sizes run much faster
+ // specialize the cases with small separator lengths
+ $num => {
+ for s in iter {
+ copy_slice_and_advance!(target, sep_bytes);
+ let content_bytes = s.borrow().as_ref();
+ copy_slice_and_advance!(target, content_bytes);
+ }
+ },
+ )*
+ _ => {
+ // arbitrary non-zero size fallback
+ for s in iter {
+ copy_slice_and_advance!(target, sep_bytes);
+ let content_bytes = s.borrow().as_ref();
+ copy_slice_and_advance!(target, content_bytes);
+ }
+ }
+ }
+ target
+ }}
+}
+
+#[cfg(not(no_global_oom_handling))]
+macro_rules! copy_slice_and_advance {
+ ($target:expr, $bytes:expr) => {
+ let len = $bytes.len();
+ let (head, tail) = { $target }.split_at_mut(len);
+ head.copy_from_slice($bytes);
+ $target = tail;
+ };
+}
+
+// Optimized join implementation that works for both Vec<T> (T: Copy) and String's inner vec
+// Currently (2018-05-13) there is a bug with type inference and specialization (see issue #36262)
+// For this reason SliceConcat<T> is not specialized for T: Copy and SliceConcat<str> is the
+// only user of this function. It is left in place for the time when that is fixed.
+//
+// the bounds for String-join are S: Borrow<str> and for Vec-join Borrow<[T]>
+// [T] and str both impl AsRef<[T]> for some T
+// => s.borrow().as_ref() and we always have slices
+#[cfg(not(no_global_oom_handling))]
+fn join_generic_copy<B, T, S>(slice: &[S], sep: &[T]) -> Vec<T>
+where
+ T: Copy,
+ B: AsRef<[T]> + ?Sized,
+ S: Borrow<B>,
+{
+ let sep_len = sep.len();
+ let mut iter = slice.iter();
+
+ // the first slice is the only one without a separator preceding it
+ let first = match iter.next() {
+ Some(first) => first,
+ None => return vec![],
+ };
+
+ // compute the exact total length of the joined Vec
+ // if the `len` calculation overflows, we'll panic
+ // we would have run out of memory anyway and the rest of the function requires
+ // the entire Vec pre-allocated for safety
+ let reserved_len = sep_len
+ .checked_mul(iter.len())
+ .and_then(|n| {
+ slice.iter().map(|s| s.borrow().as_ref().len()).try_fold(n, usize::checked_add)
+ })
+ .expect("attempt to join into collection with len > usize::MAX");
+
+ // prepare an uninitialized buffer
+ let mut result = Vec::with_capacity(reserved_len);
+ debug_assert!(result.capacity() >= reserved_len);
+
+ result.extend_from_slice(first.borrow().as_ref());
+
+ unsafe {
+ let pos = result.len();
+ let target = result.spare_capacity_mut().get_unchecked_mut(..reserved_len - pos);
+
+ // Convert the separator and slices to slices of MaybeUninit
+ // to simplify implementation in specialize_for_lengths
+ let sep_uninit = core::slice::from_raw_parts(sep.as_ptr().cast(), sep.len());
+ let iter_uninit = iter.map(|it| {
+ let it = it.borrow().as_ref();
+ core::slice::from_raw_parts(it.as_ptr().cast(), it.len())
+ });
+
+ // copy separator and slices over without bounds checks
+ // generate loops with hardcoded offsets for small separators
+ // massive improvements possible (~ x2)
+ let remain = specialize_for_lengths!(sep_uninit, target, iter_uninit; 0, 1, 2, 3, 4);
+
+ // A weird borrow implementation may return different
+ // slices for the length calculation and the actual copy.
+ // Make sure we don't expose uninitialized bytes to the caller.
+ let result_len = reserved_len - remain.len();
+ result.set_len(result_len);
+ }
+ result
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Borrow<str> for String {
+ #[inline]
+ fn borrow(&self) -> &str {
+ &self[..]
+ }
+}
+
+#[stable(feature = "string_borrow_mut", since = "1.36.0")]
+impl BorrowMut<str> for String {
+ #[inline]
+ fn borrow_mut(&mut self) -> &mut str {
+ &mut self[..]
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToOwned for str {
+ type Owned = String;
+ #[inline]
+ fn to_owned(&self) -> String {
+ unsafe { String::from_utf8_unchecked(self.as_bytes().to_owned()) }
+ }
+
+ fn clone_into(&self, target: &mut String) {
+ let mut b = mem::take(target).into_bytes();
+ self.as_bytes().clone_into(&mut b);
+ *target = unsafe { String::from_utf8_unchecked(b) }
+ }
+}
+
+/// Methods for string slices.
+#[lang = "str_alloc"]
+#[cfg(not(test))]
+impl str {
+ /// Converts a `Box<str>` into a `Box<[u8]>` without copying or allocating.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = "this is a string";
+ /// let boxed_str = s.to_owned().into_boxed_str();
+ /// let boxed_bytes = boxed_str.into_boxed_bytes();
+ /// assert_eq!(*boxed_bytes, *s.as_bytes());
+ /// ```
+ #[stable(feature = "str_box_extras", since = "1.20.0")]
+ #[must_use = "`self` will be dropped if the result is not used"]
+ #[inline]
+ pub fn into_boxed_bytes(self: Box<str>) -> Box<[u8]> {
+ self.into()
+ }
+
+ /// Replaces all matches of a pattern with another string.
+ ///
+ /// `replace` creates a new [`String`], and copies the data from this string slice into it.
+ /// While doing so, it attempts to find matches of a pattern. If it finds any, it
+ /// replaces them with the replacement string slice.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = "this is old";
+ ///
+ /// assert_eq!("this is new", s.replace("old", "new"));
+ /// ```
+ ///
+ /// When the pattern doesn't match:
+ ///
+ /// ```
+ /// let s = "this is old";
+ /// assert_eq!(s, s.replace("cookie monster", "little lamb"));
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "this returns the replaced string as a new allocation, \
+ without modifying the original"]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[inline]
+ pub fn replace<'a, P: Pattern<'a>>(&'a self, from: P, to: &str) -> String {
+ let mut result = String::new();
+ let mut last_end = 0;
+ for (start, part) in self.match_indices(from) {
+ result.push_str(unsafe { self.get_unchecked(last_end..start) });
+ result.push_str(to);
+ last_end = start + part.len();
+ }
+ result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
+ result
+ }
+
+ /// Replaces first N matches of a pattern with another string.
+ ///
+ /// `replacen` creates a new [`String`], and copies the data from this string slice into it.
+ /// While doing so, it attempts to find matches of a pattern. If it finds any, it
+ /// replaces them with the replacement string slice at most `count` times.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = "foo foo 123 foo";
+ /// assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));
+ /// assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3));
+ /// assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));
+ /// ```
+ ///
+ /// When the pattern doesn't match:
+ ///
+ /// ```
+ /// let s = "this is old";
+ /// assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "this returns the replaced string as a new allocation, \
+ without modifying the original"]
+ #[stable(feature = "str_replacen", since = "1.16.0")]
+ pub fn replacen<'a, P: Pattern<'a>>(&'a self, pat: P, to: &str, count: usize) -> String {
+ // Hope to reduce the times of re-allocation
+ let mut result = String::with_capacity(32);
+ let mut last_end = 0;
+ for (start, part) in self.match_indices(pat).take(count) {
+ result.push_str(unsafe { self.get_unchecked(last_end..start) });
+ result.push_str(to);
+ last_end = start + part.len();
+ }
+ result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
+ result
+ }
+
+ /// Returns the lowercase equivalent of this string slice, as a new [`String`].
+ ///
+ /// 'Lowercase' is defined according to the terms of the Unicode Derived Core Property
+ /// `Lowercase`.
+ ///
+ /// Since some characters can expand into multiple characters when changing
+ /// the case, this function returns a [`String`] instead of modifying the
+ /// parameter in-place.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = "HELLO";
+ ///
+ /// assert_eq!("hello", s.to_lowercase());
+ /// ```
+ ///
+ /// A tricky example, with sigma:
+ ///
+ /// ```
+ /// let sigma = "Σ";
+ ///
+ /// assert_eq!("σ", sigma.to_lowercase());
+ ///
+ /// // but at the end of a word, it's ς, not σ:
+ /// let odysseus = "ὈΔΥΣΣΕΎΣ";
+ ///
+ /// assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());
+ /// ```
+ ///
+ /// Languages without case are not changed:
+ ///
+ /// ```
+ /// let new_year = "农历新年";
+ ///
+ /// assert_eq!(new_year, new_year.to_lowercase());
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "this returns the lowercase string as a new String, \
+ without modifying the original"]
+ #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
+ pub fn to_lowercase(&self) -> String {
+ let mut s = String::with_capacity(self.len());
+ for (i, c) in self[..].char_indices() {
+ if c == 'Σ' {
+ // Σ maps to σ, except at the end of a word where it maps to ς.
+ // This is the only conditional (contextual) but language-independent mapping
+ // in `SpecialCasing.txt`,
+ // so hard-code it rather than have a generic "condition" mechanism.
+ // See https://github.com/rust-lang/rust/issues/26035
+ map_uppercase_sigma(self, i, &mut s)
+ } else {
+ match conversions::to_lower(c) {
+ [a, '\0', _] => s.push(a),
+ [a, b, '\0'] => {
+ s.push(a);
+ s.push(b);
+ }
+ [a, b, c] => {
+ s.push(a);
+ s.push(b);
+ s.push(c);
+ }
+ }
+ }
+ }
+ return s;
+
+ fn map_uppercase_sigma(from: &str, i: usize, to: &mut String) {
+ // See https://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992
+ // for the definition of `Final_Sigma`.
+ debug_assert!('Σ'.len_utf8() == 2);
+ let is_word_final = case_ignoreable_then_cased(from[..i].chars().rev())
+ && !case_ignoreable_then_cased(from[i + 2..].chars());
+ to.push_str(if is_word_final { "ς" } else { "σ" });
+ }
+
+ fn case_ignoreable_then_cased<I: Iterator<Item = char>>(iter: I) -> bool {
+ use core::unicode::{Case_Ignorable, Cased};
+ match iter.skip_while(|&c| Case_Ignorable(c)).next() {
+ Some(c) => Cased(c),
+ None => false,
+ }
+ }
+ }
+
+ /// Returns the uppercase equivalent of this string slice, as a new [`String`].
+ ///
+ /// 'Uppercase' is defined according to the terms of the Unicode Derived Core Property
+ /// `Uppercase`.
+ ///
+ /// Since some characters can expand into multiple characters when changing
+ /// the case, this function returns a [`String`] instead of modifying the
+ /// parameter in-place.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = "hello";
+ ///
+ /// assert_eq!("HELLO", s.to_uppercase());
+ /// ```
+ ///
+ /// Scripts without case are not changed:
+ ///
+ /// ```
+ /// let new_year = "农历新年";
+ ///
+ /// assert_eq!(new_year, new_year.to_uppercase());
+ /// ```
+ ///
+ /// One character can become multiple:
+ /// ```
+ /// let s = "tschüß";
+ ///
+ /// assert_eq!("TSCHÜSS", s.to_uppercase());
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "this returns the uppercase string as a new String, \
+ without modifying the original"]
+ #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
+ pub fn to_uppercase(&self) -> String {
+ let mut s = String::with_capacity(self.len());
+ for c in self[..].chars() {
+ match conversions::to_upper(c) {
+ [a, '\0', _] => s.push(a),
+ [a, b, '\0'] => {
+ s.push(a);
+ s.push(b);
+ }
+ [a, b, c] => {
+ s.push(a);
+ s.push(b);
+ s.push(c);
+ }
+ }
+ }
+ s
+ }
+
+ /// Converts a [`Box<str>`] into a [`String`] without copying or allocating.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let string = String::from("birthday gift");
+ /// let boxed_str = string.clone().into_boxed_str();
+ ///
+ /// assert_eq!(boxed_str.into_string(), string);
+ /// ```
+ #[stable(feature = "box_str", since = "1.4.0")]
+ #[must_use = "`self` will be dropped if the result is not used"]
+ #[inline]
+ pub fn into_string(self: Box<str>) -> String {
+ let slice = Box::<[u8]>::from(self);
+ unsafe { String::from_utf8_unchecked(slice.into_vec()) }
+ }
+
+ /// Creates a new [`String`] by repeating a string `n` times.
+ ///
+ /// # Panics
+ ///
+ /// This function will panic if the capacity would overflow.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));
+ /// ```
+ ///
+ /// A panic upon overflow:
+ ///
+ /// ```should_panic
+ /// // this will panic at runtime
+ /// let huge = "0123456789abcdef".repeat(usize::MAX);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use]
+ #[stable(feature = "repeat_str", since = "1.16.0")]
+ pub fn repeat(&self, n: usize) -> String {
+ unsafe { String::from_utf8_unchecked(self.as_bytes().repeat(n)) }
+ }
+
+ /// Returns a copy of this string where each character is mapped to its
+ /// ASCII upper case equivalent.
+ ///
+ /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+ /// but non-ASCII letters are unchanged.
+ ///
+ /// To uppercase the value in-place, use [`make_ascii_uppercase`].
+ ///
+ /// To uppercase ASCII characters in addition to non-ASCII characters, use
+ /// [`to_uppercase`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let s = "Grüße, Jürgen ❤";
+ ///
+ /// assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());
+ /// ```
+ ///
+ /// [`make_ascii_uppercase`]: str::make_ascii_uppercase
+ /// [`to_uppercase`]: #method.to_uppercase
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "to uppercase the value in-place, use `make_ascii_uppercase()`"]
+ #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+ #[inline]
+ pub fn to_ascii_uppercase(&self) -> String {
+ let mut bytes = self.as_bytes().to_vec();
+ bytes.make_ascii_uppercase();
+ // make_ascii_uppercase() preserves the UTF-8 invariant.
+ unsafe { String::from_utf8_unchecked(bytes) }
+ }
+
+ /// Returns a copy of this string where each character is mapped to its
+ /// ASCII lower case equivalent.
+ ///
+ /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+ /// but non-ASCII letters are unchanged.
+ ///
+ /// To lowercase the value in-place, use [`make_ascii_lowercase`].
+ ///
+ /// To lowercase ASCII characters in addition to non-ASCII characters, use
+ /// [`to_lowercase`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let s = "Grüße, Jürgen ❤";
+ ///
+ /// assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());
+ /// ```
+ ///
+ /// [`make_ascii_lowercase`]: str::make_ascii_lowercase
+ /// [`to_lowercase`]: #method.to_lowercase
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use = "to lowercase the value in-place, use `make_ascii_lowercase()`"]
+ #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+ #[inline]
+ pub fn to_ascii_lowercase(&self) -> String {
+ let mut bytes = self.as_bytes().to_vec();
+ bytes.make_ascii_lowercase();
+ // make_ascii_lowercase() preserves the UTF-8 invariant.
+ unsafe { String::from_utf8_unchecked(bytes) }
+ }
+}
+
+/// Converts a boxed slice of bytes to a boxed string slice without checking
+/// that the string contains valid UTF-8.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// let smile_utf8 = Box::new([226, 152, 186]);
+/// let smile = unsafe { std::str::from_boxed_utf8_unchecked(smile_utf8) };
+///
+/// assert_eq!("☺", &*smile);
+/// ```
+#[stable(feature = "str_box_extras", since = "1.20.0")]
+#[must_use]
+#[inline]
+pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> {
+ unsafe { Box::from_raw(Box::into_raw(v) as *mut str) }
+}
diff --git a/rust/alloc/string.rs b/rust/alloc/string.rs
new file mode 100644
index 000000000000..716bb4983a65
--- /dev/null
+++ b/rust/alloc/string.rs
@@ -0,0 +1,2867 @@
+//! A UTF-8–encoded, growable string.
+//!
+//! This module contains the [`String`] type, the [`ToString`] trait for
+//! converting to strings, and several error types that may result from
+//! working with [`String`]s.
+//!
+//! # Examples
+//!
+//! There are multiple ways to create a new [`String`] from a string literal:
+//!
+//! ```
+//! let s = "Hello".to_string();
+//!
+//! let s = String::from("world");
+//! let s: String = "also this".into();
+//! ```
+//!
+//! You can create a new [`String`] from an existing one by concatenating with
+//! `+`:
+//!
+//! ```
+//! let s = "Hello".to_string();
+//!
+//! let message = s + " world!";
+//! ```
+//!
+//! If you have a vector of valid UTF-8 bytes, you can make a [`String`] out of
+//! it. You can do the reverse too.
+//!
+//! ```
+//! let sparkle_heart = vec![240, 159, 146, 150];
+//!
+//! // We know these bytes are valid, so we'll use `unwrap()`.
+//! let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
+//!
+//! assert_eq!("💖", sparkle_heart);
+//!
+//! let bytes = sparkle_heart.into_bytes();
+//!
+//! assert_eq!(bytes, [240, 159, 146, 150]);
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[cfg(not(no_global_oom_handling))]
+use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
+use core::fmt;
+use core::hash;
+#[cfg(not(no_global_oom_handling))]
+use core::iter::FromIterator;
+use core::iter::{from_fn, FusedIterator};
+#[cfg(not(no_global_oom_handling))]
+use core::ops::Add;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::AddAssign;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::Bound::{Excluded, Included, Unbounded};
+use core::ops::{self, Index, IndexMut, Range, RangeBounds};
+use core::ptr;
+use core::slice;
+#[cfg(not(no_global_oom_handling))]
+use core::str::lossy;
+use core::str::pattern::Pattern;
+
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::{Cow, ToOwned};
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::str::{self, Chars, Utf8Error};
+#[cfg(not(no_global_oom_handling))]
+use crate::str::{from_boxed_utf8_unchecked, FromStr};
+use crate::vec::Vec;
+
+/// A UTF-8–encoded, growable string.
+///
+/// The `String` type is the most common string type that has ownership over the
+/// contents of the string. It has a close relationship with its borrowed
+/// counterpart, the primitive [`str`].
+///
+/// # Examples
+///
+/// You can create a `String` from [a literal string][`&str`] with [`String::from`]:
+///
+/// [`String::from`]: From::from
+///
+/// ```
+/// let hello = String::from("Hello, world!");
+/// ```
+///
+/// You can append a [`char`] to a `String` with the [`push`] method, and
+/// append a [`&str`] with the [`push_str`] method:
+///
+/// ```
+/// let mut hello = String::from("Hello, ");
+///
+/// hello.push('w');
+/// hello.push_str("orld!");
+/// ```
+///
+/// [`push`]: String::push
+/// [`push_str`]: String::push_str
+///
+/// If you have a vector of UTF-8 bytes, you can create a `String` from it with
+/// the [`from_utf8`] method:
+///
+/// ```
+/// // some bytes, in a vector
+/// let sparkle_heart = vec![240, 159, 146, 150];
+///
+/// // We know these bytes are valid, so we'll use `unwrap()`.
+/// let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
+///
+/// assert_eq!("💖", sparkle_heart);
+/// ```
+///
+/// [`from_utf8`]: String::from_utf8
+///
+/// # UTF-8
+///
+/// `String`s are always valid UTF-8. This has a few implications, the first of
+/// which is that if you need a non-UTF-8 string, consider [`OsString`]. It is
+/// similar, but without the UTF-8 constraint. The second implication is that
+/// you cannot index into a `String`:
+///
+/// ```compile_fail,E0277
+/// let s = "hello";
+///
+/// println!("The first letter of s is {}", s[0]); // ERROR!!!
+/// ```
+///
+/// [`OsString`]: ../../std/ffi/struct.OsString.html "ffi::OsString"
+///
+/// Indexing is intended to be a constant-time operation, but UTF-8 encoding
+/// does not allow us to do this. Furthermore, it's not clear what sort of
+/// thing the index should return: a byte, a codepoint, or a grapheme cluster.
+/// The [`bytes`] and [`chars`] methods return iterators over the first
+/// two, respectively.
+///
+/// [`bytes`]: str::bytes
+/// [`chars`]: str::chars
+///
+/// # Deref
+///
+/// `String` implements <code>[Deref]<Target = [str]></code>, and so inherits all of [`str`]'s
+/// methods. In addition, this means that you can pass a `String` to a
+/// function which takes a [`&str`] by using an ampersand (`&`):
+///
+/// ```
+/// fn takes_str(s: &str) { }
+///
+/// let s = String::from("Hello");
+///
+/// takes_str(&s);
+/// ```
+///
+/// This will create a [`&str`] from the `String` and pass it in. This
+/// conversion is very inexpensive, and so generally, functions will accept
+/// [`&str`]s as arguments unless they need a `String` for some specific
+/// reason.
+///
+/// In certain cases Rust doesn't have enough information to make this
+/// conversion, known as [`Deref`] coercion. In the following example a string
+/// slice [`&'a str`][`&str`] implements the trait `TraitExample`, and the function
+/// `example_func` takes anything that implements the trait. In this case Rust
+/// would need to make two implicit conversions, which Rust doesn't have the
+/// means to do. For that reason, the following example will not compile.
+///
+/// ```compile_fail,E0277
+/// trait TraitExample {}
+///
+/// impl<'a> TraitExample for &'a str {}
+///
+/// fn example_func<A: TraitExample>(example_arg: A) {}
+///
+/// let example_string = String::from("example_string");
+/// example_func(&example_string);
+/// ```
+///
+/// There are two options that would work instead. The first would be to
+/// change the line `example_func(&example_string);` to
+/// `example_func(example_string.as_str());`, using the method [`as_str()`]
+/// to explicitly extract the string slice containing the string. The second
+/// way changes `example_func(&example_string);` to
+/// `example_func(&*example_string);`. In this case we are dereferencing a
+/// `String` to a [`str`], then referencing the [`str`] back to
+/// [`&str`]. The second way is more idiomatic, however both work to do the
+/// conversion explicitly rather than relying on the implicit conversion.
+///
+/// # Representation
+///
+/// A `String` is made up of three components: a pointer to some bytes, a
+/// length, and a capacity. The pointer points to an internal buffer `String`
+/// uses to store its data. The length is the number of bytes currently stored
+/// in the buffer, and the capacity is the size of the buffer in bytes. As such,
+/// the length will always be less than or equal to the capacity.
+///
+/// This buffer is always stored on the heap.
+///
+/// You can look at these with the [`as_ptr`], [`len`], and [`capacity`]
+/// methods:
+///
+/// ```
+/// use std::mem;
+///
+/// let story = String::from("Once upon a time...");
+///
+// FIXME Update this when vec_into_raw_parts is stabilized
+/// // Prevent automatically dropping the String's data
+/// let mut story = mem::ManuallyDrop::new(story);
+///
+/// let ptr = story.as_mut_ptr();
+/// let len = story.len();
+/// let capacity = story.capacity();
+///
+/// // story has nineteen bytes
+/// assert_eq!(19, len);
+///
+/// // We can re-build a String out of ptr, len, and capacity. This is all
+/// // unsafe because we are responsible for making sure the components are
+/// // valid:
+/// let s = unsafe { String::from_raw_parts(ptr, len, capacity) } ;
+///
+/// assert_eq!(String::from("Once upon a time..."), s);
+/// ```
+///
+/// [`as_ptr`]: str::as_ptr
+/// [`len`]: String::len
+/// [`capacity`]: String::capacity
+///
+/// If a `String` has enough capacity, adding elements to it will not
+/// re-allocate. For example, consider this program:
+///
+/// ```
+/// let mut s = String::new();
+///
+/// println!("{}", s.capacity());
+///
+/// for _ in 0..5 {
+/// s.push_str("hello");
+/// println!("{}", s.capacity());
+/// }
+/// ```
+///
+/// This will output the following:
+///
+/// ```text
+/// 0
+/// 5
+/// 10
+/// 20
+/// 20
+/// 40
+/// ```
+///
+/// At first, we have no memory allocated at all, but as we append to the
+/// string, it increases its capacity appropriately. If we instead use the
+/// [`with_capacity`] method to allocate the correct capacity initially:
+///
+/// ```
+/// let mut s = String::with_capacity(25);
+///
+/// println!("{}", s.capacity());
+///
+/// for _ in 0..5 {
+/// s.push_str("hello");
+/// println!("{}", s.capacity());
+/// }
+/// ```
+///
+/// [`with_capacity`]: String::with_capacity
+///
+/// We end up with a different output:
+///
+/// ```text
+/// 25
+/// 25
+/// 25
+/// 25
+/// 25
+/// 25
+/// ```
+///
+/// Here, there's no need to allocate more memory inside the loop.
+///
+/// [str]: prim@str "str"
+/// [`str`]: prim@str "str"
+/// [`&str`]: prim@str "&str"
+/// [Deref]: core::ops::Deref "ops::Deref"
+/// [`Deref`]: core::ops::Deref "ops::Deref"
+/// [`as_str()`]: String::as_str
+#[derive(PartialOrd, Eq, Ord)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "String")]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct String {
+ vec: Vec<u8>,
+}
+
+/// A possible error value when converting a `String` from a UTF-8 byte vector.
+///
+/// This type is the error type for the [`from_utf8`] method on [`String`]. It
+/// is designed in such a way to carefully avoid reallocations: the
+/// [`into_bytes`] method will give back the byte vector that was used in the
+/// conversion attempt.
+///
+/// [`from_utf8`]: String::from_utf8
+/// [`into_bytes`]: FromUtf8Error::into_bytes
+///
+/// The [`Utf8Error`] type provided by [`std::str`] represents an error that may
+/// occur when converting a slice of [`u8`]s to a [`&str`]. In this sense, it's
+/// an analogue to `FromUtf8Error`, and you can get one from a `FromUtf8Error`
+/// through the [`utf8_error`] method.
+///
+/// [`Utf8Error`]: str::Utf8Error "std::str::Utf8Error"
+/// [`std::str`]: core::str "std::str"
+/// [`&str`]: prim@str "&str"
+/// [`utf8_error`]: FromUtf8Error::utf8_error
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// // some invalid bytes, in a vector
+/// let bytes = vec![0, 159];
+///
+/// let value = String::from_utf8(bytes);
+///
+/// assert!(value.is_err());
+/// assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(no_global_oom_handling), derive(Clone))]
+#[derive(Debug, PartialEq, Eq)]
+pub struct FromUtf8Error {
+ bytes: Vec<u8>,
+ error: Utf8Error,
+}
+
+/// A possible error value when converting a `String` from a UTF-16 byte slice.
+///
+/// This type is the error type for the [`from_utf16`] method on [`String`].
+///
+/// [`from_utf16`]: String::from_utf16
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// // 𝄞mu<invalid>ic
+/// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+/// 0xD800, 0x0069, 0x0063];
+///
+/// assert!(String::from_utf16(v).is_err());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
+pub struct FromUtf16Error(());
+
+impl String {
+ /// Creates a new empty `String`.
+ ///
+ /// Given that the `String` is empty, this will not allocate any initial
+ /// buffer. While that means that this initial operation is very
+ /// inexpensive, it may cause excessive allocation later when you add
+ /// data. If you have an idea of how much data the `String` will hold,
+ /// consider the [`with_capacity`] method to prevent excessive
+ /// re-allocation.
+ ///
+ /// [`with_capacity`]: String::with_capacity
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = String::new();
+ /// ```
+ #[inline]
+ #[rustc_const_stable(feature = "const_string_new", since = "1.39.0")]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
+ pub const fn new() -> String {
+ String { vec: Vec::new() }
+ }
+
+ /// Creates a new empty `String` with a particular capacity.
+ ///
+ /// `String`s have an internal buffer to hold their data. The capacity is
+ /// the length of that buffer, and can be queried with the [`capacity`]
+ /// method. This method creates an empty `String`, but one with an initial
+ /// buffer that can hold `capacity` bytes. This is useful when you may be
+ /// appending a bunch of data to the `String`, reducing the number of
+ /// reallocations it needs to do.
+ ///
+ /// [`capacity`]: String::capacity
+ ///
+ /// If the given capacity is `0`, no allocation will occur, and this method
+ /// is identical to the [`new`] method.
+ ///
+ /// [`new`]: String::new
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::with_capacity(10);
+ ///
+ /// // The String contains no chars, even though it has capacity for more
+ /// assert_eq!(s.len(), 0);
+ ///
+ /// // These are all done without reallocating...
+ /// let cap = s.capacity();
+ /// for _ in 0..10 {
+ /// s.push('a');
+ /// }
+ ///
+ /// assert_eq!(s.capacity(), cap);
+ ///
+ /// // ...but this may make the string reallocate
+ /// s.push('a');
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
+ pub fn with_capacity(capacity: usize) -> String {
+ String { vec: Vec::with_capacity(capacity) }
+ }
+
+ // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
+ // required for this method definition, is not available. Since we don't
+ // require this method for testing purposes, I'll just stub it
+ // NB see the slice::hack module in slice.rs for more information
+ #[inline]
+ #[cfg(test)]
+ pub fn from_str(_: &str) -> String {
+ panic!("not available with cfg(test)");
+ }
+
+ /// Converts a vector of bytes to a `String`.
+ ///
+ /// A string ([`String`]) is made of bytes ([`u8`]), and a vector of bytes
+ /// ([`Vec<u8>`]) is made of bytes, so this function converts between the
+ /// two. Not all byte slices are valid `String`s, however: `String`
+ /// requires that it is valid UTF-8. `from_utf8()` checks to ensure that
+ /// the bytes are valid UTF-8, and then does the conversion.
+ ///
+ /// If you are sure that the byte slice is valid UTF-8, and you don't want
+ /// to incur the overhead of the validity check, there is an unsafe version
+ /// of this function, [`from_utf8_unchecked`], which has the same behavior
+ /// but skips the check.
+ ///
+ /// This method will take care to not copy the vector, for efficiency's
+ /// sake.
+ ///
+ /// If you need a [`&str`] instead of a `String`, consider
+ /// [`str::from_utf8`].
+ ///
+ /// The inverse of this method is [`into_bytes`].
+ ///
+ /// # Errors
+ ///
+ /// Returns [`Err`] if the slice is not UTF-8 with a description as to why the
+ /// provided bytes are not UTF-8. The vector you moved in is also included.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // some bytes, in a vector
+ /// let sparkle_heart = vec![240, 159, 146, 150];
+ ///
+ /// // We know these bytes are valid, so we'll use `unwrap()`.
+ /// let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
+ ///
+ /// assert_eq!("💖", sparkle_heart);
+ /// ```
+ ///
+ /// Incorrect bytes:
+ ///
+ /// ```
+ /// // some invalid bytes, in a vector
+ /// let sparkle_heart = vec![0, 159, 146, 150];
+ ///
+ /// assert!(String::from_utf8(sparkle_heart).is_err());
+ /// ```
+ ///
+ /// See the docs for [`FromUtf8Error`] for more details on what you can do
+ /// with this error.
+ ///
+ /// [`from_utf8_unchecked`]: String::from_utf8_unchecked
+ /// [`Vec<u8>`]: crate::vec::Vec "Vec"
+ /// [`&str`]: prim@str "&str"
+ /// [`into_bytes`]: String::into_bytes
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn from_utf8(vec: Vec<u8>) -> Result<String, FromUtf8Error> {
+ match str::from_utf8(&vec) {
+ Ok(..) => Ok(String { vec }),
+ Err(e) => Err(FromUtf8Error { bytes: vec, error: e }),
+ }
+ }
+
+ /// Converts a slice of bytes to a string, including invalid characters.
+ ///
+ /// Strings are made of bytes ([`u8`]), and a slice of bytes
+ /// ([`&[u8]`][byteslice]) is made of bytes, so this function converts
+ /// between the two. Not all byte slices are valid strings, however: strings
+ /// are required to be valid UTF-8. During this conversion,
+ /// `from_utf8_lossy()` will replace any invalid UTF-8 sequences with
+ /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD], which looks like this: �
+ ///
+ /// [byteslice]: prim@slice
+ /// [U+FFFD]: core::char::REPLACEMENT_CHARACTER
+ ///
+ /// If you are sure that the byte slice is valid UTF-8, and you don't want
+ /// to incur the overhead of the conversion, there is an unsafe version
+ /// of this function, [`from_utf8_unchecked`], which has the same behavior
+ /// but skips the checks.
+ ///
+ /// [`from_utf8_unchecked`]: String::from_utf8_unchecked
+ ///
+ /// This function returns a [`Cow<'a, str>`]. If our byte slice is invalid
+ /// UTF-8, then we need to insert the replacement characters, which will
+ /// change the size of the string, and hence, require a `String`. But if
+ /// it's already valid UTF-8, we don't need a new allocation. This return
+ /// type allows us to handle both cases.
+ ///
+ /// [`Cow<'a, str>`]: crate::borrow::Cow "borrow::Cow"
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // some bytes, in a vector
+ /// let sparkle_heart = vec![240, 159, 146, 150];
+ ///
+ /// let sparkle_heart = String::from_utf8_lossy(&sparkle_heart);
+ ///
+ /// assert_eq!("💖", sparkle_heart);
+ /// ```
+ ///
+ /// Incorrect bytes:
+ ///
+ /// ```
+ /// // some invalid bytes
+ /// let input = b"Hello \xF0\x90\x80World";
+ /// let output = String::from_utf8_lossy(input);
+ ///
+ /// assert_eq!("Hello �World", output);
+ /// ```
+ #[must_use]
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn from_utf8_lossy(v: &[u8]) -> Cow<'_, str> {
+ let mut iter = lossy::Utf8Lossy::from_bytes(v).chunks();
+
+ let first_valid = if let Some(chunk) = iter.next() {
+ let lossy::Utf8LossyChunk { valid, broken } = chunk;
+ if broken.is_empty() {
+ debug_assert_eq!(valid.len(), v.len());
+ return Cow::Borrowed(valid);
+ }
+ valid
+ } else {
+ return Cow::Borrowed("");
+ };
+
+ const REPLACEMENT: &str = "\u{FFFD}";
+
+ let mut res = String::with_capacity(v.len());
+ res.push_str(first_valid);
+ res.push_str(REPLACEMENT);
+
+ for lossy::Utf8LossyChunk { valid, broken } in iter {
+ res.push_str(valid);
+ if !broken.is_empty() {
+ res.push_str(REPLACEMENT);
+ }
+ }
+
+ Cow::Owned(res)
+ }
+
+ /// Decode a UTF-16–encoded vector `v` into a `String`, returning [`Err`]
+ /// if `v` contains any invalid data.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // 𝄞music
+ /// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+ /// 0x0073, 0x0069, 0x0063];
+ /// assert_eq!(String::from("𝄞music"),
+ /// String::from_utf16(v).unwrap());
+ ///
+ /// // 𝄞mu<invalid>ic
+ /// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+ /// 0xD800, 0x0069, 0x0063];
+ /// assert!(String::from_utf16(v).is_err());
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn from_utf16(v: &[u16]) -> Result<String, FromUtf16Error> {
+ // This isn't done via collect::<Result<_, _>>() for performance reasons.
+ // FIXME: the function can be simplified again when #48994 is closed.
+ let mut ret = String::with_capacity(v.len());
+ for c in decode_utf16(v.iter().cloned()) {
+ if let Ok(c) = c {
+ ret.push(c);
+ } else {
+ return Err(FromUtf16Error(()));
+ }
+ }
+ Ok(ret)
+ }
+
+ /// Decode a UTF-16–encoded slice `v` into a `String`, replacing
+ /// invalid data with [the replacement character (`U+FFFD`)][U+FFFD].
+ ///
+ /// Unlike [`from_utf8_lossy`] which returns a [`Cow<'a, str>`],
+ /// `from_utf16_lossy` returns a `String` since the UTF-16 to UTF-8
+ /// conversion requires a memory allocation.
+ ///
+ /// [`from_utf8_lossy`]: String::from_utf8_lossy
+ /// [`Cow<'a, str>`]: crate::borrow::Cow "borrow::Cow"
+ /// [U+FFFD]: core::char::REPLACEMENT_CHARACTER
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // 𝄞mus<invalid>ic<invalid>
+ /// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+ /// 0x0073, 0xDD1E, 0x0069, 0x0063,
+ /// 0xD834];
+ ///
+ /// assert_eq!(String::from("𝄞mus\u{FFFD}ic\u{FFFD}"),
+ /// String::from_utf16_lossy(v));
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[must_use]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn from_utf16_lossy(v: &[u16]) -> String {
+ decode_utf16(v.iter().cloned()).map(|r| r.unwrap_or(REPLACEMENT_CHARACTER)).collect()
+ }
+
+ /// Decomposes a `String` into its raw components.
+ ///
+ /// Returns the raw pointer to the underlying data, the length of
+ /// the string (in bytes), and the allocated capacity of the data
+ /// (in bytes). These are the same arguments in the same order as
+ /// the arguments to [`from_raw_parts`].
+ ///
+ /// After calling this function, the caller is responsible for the
+ /// memory previously managed by the `String`. The only way to do
+ /// this is to convert the raw pointer, length, and capacity back
+ /// into a `String` with the [`from_raw_parts`] function, allowing
+ /// the destructor to perform the cleanup.
+ ///
+ /// [`from_raw_parts`]: String::from_raw_parts
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(vec_into_raw_parts)]
+ /// let s = String::from("hello");
+ ///
+ /// let (ptr, len, cap) = s.into_raw_parts();
+ ///
+ /// let rebuilt = unsafe { String::from_raw_parts(ptr, len, cap) };
+ /// assert_eq!(rebuilt, "hello");
+ /// ```
+ #[must_use = "`self` will be dropped if the result is not used"]
+ #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
+ pub fn into_raw_parts(self) -> (*mut u8, usize, usize) {
+ self.vec.into_raw_parts()
+ }
+
+ /// Creates a new `String` from a length, capacity, and pointer.
+ ///
+ /// # Safety
+ ///
+ /// This is highly unsafe, due to the number of invariants that aren't
+ /// checked:
+ ///
+ /// * The memory at `buf` needs to have been previously allocated by the
+ /// same allocator the standard library uses, with a required alignment of exactly 1.
+ /// * `length` needs to be less than or equal to `capacity`.
+ /// * `capacity` needs to be the correct value.
+ /// * The first `length` bytes at `buf` need to be valid UTF-8.
+ ///
+ /// Violating these may cause problems like corrupting the allocator's
+ /// internal data structures.
+ ///
+ /// The ownership of `buf` is effectively transferred to the
+ /// `String` which may then deallocate, reallocate or change the
+ /// contents of memory pointed to by the pointer at will. Ensure
+ /// that nothing else uses the pointer after calling this
+ /// function.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// use std::mem;
+ ///
+ /// unsafe {
+ /// let s = String::from("hello");
+ ///
+ // FIXME Update this when vec_into_raw_parts is stabilized
+ /// // Prevent automatically dropping the String's data
+ /// let mut s = mem::ManuallyDrop::new(s);
+ ///
+ /// let ptr = s.as_mut_ptr();
+ /// let len = s.len();
+ /// let capacity = s.capacity();
+ ///
+ /// let s = String::from_raw_parts(ptr, len, capacity);
+ ///
+ /// assert_eq!(String::from("hello"), s);
+ /// }
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub unsafe fn from_raw_parts(buf: *mut u8, length: usize, capacity: usize) -> String {
+ unsafe { String { vec: Vec::from_raw_parts(buf, length, capacity) } }
+ }
+
+ /// Converts a vector of bytes to a `String` without checking that the
+ /// string contains valid UTF-8.
+ ///
+ /// See the safe version, [`from_utf8`], for more details.
+ ///
+ /// [`from_utf8`]: String::from_utf8
+ ///
+ /// # Safety
+ ///
+ /// This function is unsafe because it does not check that the bytes passed
+ /// to it are valid UTF-8. If this constraint is violated, it may cause
+ /// memory unsafety issues with future users of the `String`, as the rest of
+ /// the standard library assumes that `String`s are valid UTF-8.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // some bytes, in a vector
+ /// let sparkle_heart = vec![240, 159, 146, 150];
+ ///
+ /// let sparkle_heart = unsafe {
+ /// String::from_utf8_unchecked(sparkle_heart)
+ /// };
+ ///
+ /// assert_eq!("💖", sparkle_heart);
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub unsafe fn from_utf8_unchecked(bytes: Vec<u8>) -> String {
+ String { vec: bytes }
+ }
+
+ /// Converts a `String` into a byte vector.
+ ///
+ /// This consumes the `String`, so we do not need to copy its contents.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = String::from("hello");
+ /// let bytes = s.into_bytes();
+ ///
+ /// assert_eq!(&[104, 101, 108, 108, 111][..], &bytes[..]);
+ /// ```
+ #[inline]
+ #[must_use = "`self` will be dropped if the result is not used"]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn into_bytes(self) -> Vec<u8> {
+ self.vec
+ }
+
+ /// Extracts a string slice containing the entire `String`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = String::from("foo");
+ ///
+ /// assert_eq!("foo", s.as_str());
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "string_as_str", since = "1.7.0")]
+ pub fn as_str(&self) -> &str {
+ self
+ }
+
+ /// Converts a `String` into a mutable string slice.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("foobar");
+ /// let s_mut_str = s.as_mut_str();
+ ///
+ /// s_mut_str.make_ascii_uppercase();
+ ///
+ /// assert_eq!("FOOBAR", s_mut_str);
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "string_as_str", since = "1.7.0")]
+ pub fn as_mut_str(&mut self) -> &mut str {
+ self
+ }
+
+ /// Appends a given string slice onto the end of this `String`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("foo");
+ ///
+ /// s.push_str("bar");
+ ///
+ /// assert_eq!("foobar", s);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn push_str(&mut self, string: &str) {
+ self.vec.extend_from_slice(string.as_bytes())
+ }
+
+ /// Copies elements from `src` range to the end of the string.
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the starting point or end point do not lie on a [`char`]
+ /// boundary, or if they're out of bounds.
+ ///
+ /// ## Examples
+ ///
+ /// ```
+ /// #![feature(string_extend_from_within)]
+ /// let mut string = String::from("abcde");
+ ///
+ /// string.extend_from_within(2..);
+ /// assert_eq!(string, "abcdecde");
+ ///
+ /// string.extend_from_within(..2);
+ /// assert_eq!(string, "abcdecdeab");
+ ///
+ /// string.extend_from_within(4..8);
+ /// assert_eq!(string, "abcdecdeabecde");
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "string_extend_from_within", issue = "none")]
+ pub fn extend_from_within<R>(&mut self, src: R)
+ where
+ R: RangeBounds<usize>,
+ {
+ let src @ Range { start, end } = slice::range(src, ..self.len());
+
+ assert!(self.is_char_boundary(start));
+ assert!(self.is_char_boundary(end));
+
+ self.vec.extend_from_within(src);
+ }
+
+ /// Returns this `String`'s capacity, in bytes.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = String::with_capacity(10);
+ ///
+ /// assert!(s.capacity() >= 10);
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn capacity(&self) -> usize {
+ self.vec.capacity()
+ }
+
+ /// Ensures that this `String`'s capacity is at least `additional` bytes
+ /// larger than its length.
+ ///
+ /// The capacity may be increased by more than `additional` bytes if it
+ /// chooses, to prevent frequent reallocations.
+ ///
+ /// If you do not want this "at least" behavior, see the [`reserve_exact`]
+ /// method.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity overflows [`usize`].
+ ///
+ /// [`reserve_exact`]: String::reserve_exact
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::new();
+ ///
+ /// s.reserve(10);
+ ///
+ /// assert!(s.capacity() >= 10);
+ /// ```
+ ///
+ /// This might not actually increase the capacity:
+ ///
+ /// ```
+ /// let mut s = String::with_capacity(10);
+ /// s.push('a');
+ /// s.push('b');
+ ///
+ /// // s now has a length of 2 and a capacity of 10
+ /// assert_eq!(2, s.len());
+ /// assert_eq!(10, s.capacity());
+ ///
+ /// // Since we already have an extra 8 capacity, calling this...
+ /// s.reserve(8);
+ ///
+ /// // ... doesn't actually increase.
+ /// assert_eq!(10, s.capacity());
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn reserve(&mut self, additional: usize) {
+ self.vec.reserve(additional)
+ }
+
+ /// Ensures that this `String`'s capacity is `additional` bytes
+ /// larger than its length.
+ ///
+ /// Consider using the [`reserve`] method unless you absolutely know
+ /// better than the allocator.
+ ///
+ /// [`reserve`]: String::reserve
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity overflows `usize`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::new();
+ ///
+ /// s.reserve_exact(10);
+ ///
+ /// assert!(s.capacity() >= 10);
+ /// ```
+ ///
+ /// This might not actually increase the capacity:
+ ///
+ /// ```
+ /// let mut s = String::with_capacity(10);
+ /// s.push('a');
+ /// s.push('b');
+ ///
+ /// // s now has a length of 2 and a capacity of 10
+ /// assert_eq!(2, s.len());
+ /// assert_eq!(10, s.capacity());
+ ///
+ /// // Since we already have an extra 8 capacity, calling this...
+ /// s.reserve_exact(8);
+ ///
+ /// // ... doesn't actually increase.
+ /// assert_eq!(10, s.capacity());
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn reserve_exact(&mut self, additional: usize) {
+ self.vec.reserve_exact(additional)
+ }
+
+ /// Tries to reserve capacity for at least `additional` more elements to be inserted
+ /// in the given `String`. The collection may reserve more space to avoid
+ /// frequent reallocations. After calling `reserve`, capacity will be
+ /// greater than or equal to `self.len() + additional`. Does nothing if
+ /// capacity is already sufficient.
+ ///
+ /// # Errors
+ ///
+ /// If the capacity overflows, or the allocator reports a failure, then an error
+ /// is returned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::collections::TryReserveError;
+ ///
+ /// fn process_data(data: &str) -> Result<String, TryReserveError> {
+ /// let mut output = String::new();
+ ///
+ /// // Pre-reserve the memory, exiting if we can't
+ /// output.try_reserve(data.len())?;
+ ///
+ /// // Now we know this can't OOM in the middle of our complex work
+ /// output.push_str(data);
+ ///
+ /// Ok(output)
+ /// }
+ /// # process_data("rust").expect("why is the test harness OOMing on 4 bytes?");
+ /// ```
+ #[stable(feature = "try_reserve", since = "1.57.0")]
+ pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.vec.try_reserve(additional)
+ }
+
+ /// Tries to reserve the minimum capacity for exactly `additional` more elements to
+ /// be inserted in the given `String`. After calling `reserve_exact`,
+ /// capacity will be greater than or equal to `self.len() + additional`.
+ /// Does nothing if the capacity is already sufficient.
+ ///
+ /// Note that the allocator may give the collection more space than it
+ /// requests. Therefore, capacity can not be relied upon to be precisely
+ /// minimal. Prefer [`try_reserve`] if future insertions are expected.
+ ///
+ /// [`try_reserve`]: String::try_reserve
+ ///
+ /// # Errors
+ ///
+ /// If the capacity overflows, or the allocator reports a failure, then an error
+ /// is returned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::collections::TryReserveError;
+ ///
+ /// fn process_data(data: &str) -> Result<String, TryReserveError> {
+ /// let mut output = String::new();
+ ///
+ /// // Pre-reserve the memory, exiting if we can't
+ /// output.try_reserve_exact(data.len())?;
+ ///
+ /// // Now we know this can't OOM in the middle of our complex work
+ /// output.push_str(data);
+ ///
+ /// Ok(output)
+ /// }
+ /// # process_data("rust").expect("why is the test harness OOMing on 4 bytes?");
+ /// ```
+ #[stable(feature = "try_reserve", since = "1.57.0")]
+ pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.vec.try_reserve_exact(additional)
+ }
+
+ /// Shrinks the capacity of this `String` to match its length.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("foo");
+ ///
+ /// s.reserve(100);
+ /// assert!(s.capacity() >= 100);
+ ///
+ /// s.shrink_to_fit();
+ /// assert_eq!(3, s.capacity());
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn shrink_to_fit(&mut self) {
+ self.vec.shrink_to_fit()
+ }
+
+ /// Shrinks the capacity of this `String` with a lower bound.
+ ///
+ /// The capacity will remain at least as large as both the length
+ /// and the supplied value.
+ ///
+ /// If the current capacity is less than the lower limit, this is a no-op.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut s = String::from("foo");
+ ///
+ /// s.reserve(100);
+ /// assert!(s.capacity() >= 100);
+ ///
+ /// s.shrink_to(10);
+ /// assert!(s.capacity() >= 10);
+ /// s.shrink_to(0);
+ /// assert!(s.capacity() >= 3);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "shrink_to", since = "1.56.0")]
+ pub fn shrink_to(&mut self, min_capacity: usize) {
+ self.vec.shrink_to(min_capacity)
+ }
+
+ /// Appends the given [`char`] to the end of this `String`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("abc");
+ ///
+ /// s.push('1');
+ /// s.push('2');
+ /// s.push('3');
+ ///
+ /// assert_eq!("abc123", s);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn push(&mut self, ch: char) {
+ match ch.len_utf8() {
+ 1 => self.vec.push(ch as u8),
+ _ => self.vec.extend_from_slice(ch.encode_utf8(&mut [0; 4]).as_bytes()),
+ }
+ }
+
+ /// Returns a byte slice of this `String`'s contents.
+ ///
+ /// The inverse of this method is [`from_utf8`].
+ ///
+ /// [`from_utf8`]: String::from_utf8
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = String::from("hello");
+ ///
+ /// assert_eq!(&[104, 101, 108, 108, 111], s.as_bytes());
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn as_bytes(&self) -> &[u8] {
+ &self.vec
+ }
+
+ /// Shortens this `String` to the specified length.
+ ///
+ /// If `new_len` is greater than the string's current length, this has no
+ /// effect.
+ ///
+ /// Note that this method has no effect on the allocated capacity
+ /// of the string
+ ///
+ /// # Panics
+ ///
+ /// Panics if `new_len` does not lie on a [`char`] boundary.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("hello");
+ ///
+ /// s.truncate(2);
+ ///
+ /// assert_eq!("he", s);
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn truncate(&mut self, new_len: usize) {
+ if new_len <= self.len() {
+ assert!(self.is_char_boundary(new_len));
+ self.vec.truncate(new_len)
+ }
+ }
+
+ /// Removes the last character from the string buffer and returns it.
+ ///
+ /// Returns [`None`] if this `String` is empty.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("foo");
+ ///
+ /// assert_eq!(s.pop(), Some('o'));
+ /// assert_eq!(s.pop(), Some('o'));
+ /// assert_eq!(s.pop(), Some('f'));
+ ///
+ /// assert_eq!(s.pop(), None);
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn pop(&mut self) -> Option<char> {
+ let ch = self.chars().rev().next()?;
+ let newlen = self.len() - ch.len_utf8();
+ unsafe {
+ self.vec.set_len(newlen);
+ }
+ Some(ch)
+ }
+
+ /// Removes a [`char`] from this `String` at a byte position and returns it.
+ ///
+ /// This is an *O*(*n*) operation, as it requires copying every element in the
+ /// buffer.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `idx` is larger than or equal to the `String`'s length,
+ /// or if it does not lie on a [`char`] boundary.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("foo");
+ ///
+ /// assert_eq!(s.remove(0), 'f');
+ /// assert_eq!(s.remove(1), 'o');
+ /// assert_eq!(s.remove(0), 'o');
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn remove(&mut self, idx: usize) -> char {
+ let ch = match self[idx..].chars().next() {
+ Some(ch) => ch,
+ None => panic!("cannot remove a char from the end of a string"),
+ };
+
+ let next = idx + ch.len_utf8();
+ let len = self.len();
+ unsafe {
+ ptr::copy(self.vec.as_ptr().add(next), self.vec.as_mut_ptr().add(idx), len - next);
+ self.vec.set_len(len - (next - idx));
+ }
+ ch
+ }
+
+ /// Remove all matches of pattern `pat` in the `String`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(string_remove_matches)]
+ /// let mut s = String::from("Trees are not green, the sky is not blue.");
+ /// s.remove_matches("not ");
+ /// assert_eq!("Trees are green, the sky is blue.", s);
+ /// ```
+ ///
+ /// Matches will be detected and removed iteratively, so in cases where
+ /// patterns overlap, only the first pattern will be removed:
+ ///
+ /// ```
+ /// #![feature(string_remove_matches)]
+ /// let mut s = String::from("banana");
+ /// s.remove_matches("ana");
+ /// assert_eq!("bna", s);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[unstable(feature = "string_remove_matches", reason = "new API", issue = "72826")]
+ pub fn remove_matches<'a, P>(&'a mut self, pat: P)
+ where
+ P: for<'x> Pattern<'x>,
+ {
+ use core::str::pattern::Searcher;
+
+ let rejections = {
+ let mut searcher = pat.into_searcher(self);
+ // Per Searcher::next:
+ //
+ // A Match result needs to contain the whole matched pattern,
+ // however Reject results may be split up into arbitrary many
+ // adjacent fragments. Both ranges may have zero length.
+ //
+ // In practice the implementation of Searcher::next_match tends to
+ // be more efficient, so we use it here and do some work to invert
+ // matches into rejections since that's what we want to copy below.
+ let mut front = 0;
+ let rejections: Vec<_> = from_fn(|| {
+ let (start, end) = searcher.next_match()?;
+ let prev_front = front;
+ front = end;
+ Some((prev_front, start))
+ })
+ .collect();
+ rejections.into_iter().chain(core::iter::once((front, self.len())))
+ };
+
+ let mut len = 0;
+ let ptr = self.vec.as_mut_ptr();
+
+ for (start, end) in rejections {
+ let count = end - start;
+ if start != len {
+ // SAFETY: per Searcher::next:
+ //
+ // The stream of Match and Reject values up to a Done will
+ // contain index ranges that are adjacent, non-overlapping,
+ // covering the whole haystack, and laying on utf8
+ // boundaries.
+ unsafe {
+ ptr::copy(ptr.add(start), ptr.add(len), count);
+ }
+ }
+ len += count;
+ }
+
+ unsafe {
+ self.vec.set_len(len);
+ }
+ }
+
+ /// Retains only the characters specified by the predicate.
+ ///
+ /// In other words, remove all characters `c` such that `f(c)` returns `false`.
+ /// This method operates in place, visiting each character exactly once in the
+ /// original order, and preserves the order of the retained characters.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut s = String::from("f_o_ob_ar");
+ ///
+ /// s.retain(|c| c != '_');
+ ///
+ /// assert_eq!(s, "foobar");
+ /// ```
+ ///
+ /// Because the elements are visited exactly once in the original order,
+ /// external state may be used to decide which elements to keep.
+ ///
+ /// ```
+ /// let mut s = String::from("abcde");
+ /// let keep = [false, true, true, false, true];
+ /// let mut iter = keep.iter();
+ /// s.retain(|_| *iter.next().unwrap());
+ /// assert_eq!(s, "bce");
+ /// ```
+ #[inline]
+ #[stable(feature = "string_retain", since = "1.26.0")]
+ pub fn retain<F>(&mut self, mut f: F)
+ where
+ F: FnMut(char) -> bool,
+ {
+ struct SetLenOnDrop<'a> {
+ s: &'a mut String,
+ idx: usize,
+ del_bytes: usize,
+ }
+
+ impl<'a> Drop for SetLenOnDrop<'a> {
+ fn drop(&mut self) {
+ let new_len = self.idx - self.del_bytes;
+ debug_assert!(new_len <= self.s.len());
+ unsafe { self.s.vec.set_len(new_len) };
+ }
+ }
+
+ let len = self.len();
+ let mut guard = SetLenOnDrop { s: self, idx: 0, del_bytes: 0 };
+
+ while guard.idx < len {
+ let ch = unsafe { guard.s.get_unchecked(guard.idx..len).chars().next().unwrap() };
+ let ch_len = ch.len_utf8();
+
+ if !f(ch) {
+ guard.del_bytes += ch_len;
+ } else if guard.del_bytes > 0 {
+ unsafe {
+ ptr::copy(
+ guard.s.vec.as_ptr().add(guard.idx),
+ guard.s.vec.as_mut_ptr().add(guard.idx - guard.del_bytes),
+ ch_len,
+ );
+ }
+ }
+
+ // Point idx to the next char
+ guard.idx += ch_len;
+ }
+
+ drop(guard);
+ }
+
+ /// Inserts a character into this `String` at a byte position.
+ ///
+ /// This is an *O*(*n*) operation as it requires copying every element in the
+ /// buffer.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `idx` is larger than the `String`'s length, or if it does not
+ /// lie on a [`char`] boundary.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::with_capacity(3);
+ ///
+ /// s.insert(0, 'f');
+ /// s.insert(1, 'o');
+ /// s.insert(2, 'o');
+ ///
+ /// assert_eq!("foo", s);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn insert(&mut self, idx: usize, ch: char) {
+ assert!(self.is_char_boundary(idx));
+ let mut bits = [0; 4];
+ let bits = ch.encode_utf8(&mut bits).as_bytes();
+
+ unsafe {
+ self.insert_bytes(idx, bits);
+ }
+ }
+
+ #[cfg(not(no_global_oom_handling))]
+ unsafe fn insert_bytes(&mut self, idx: usize, bytes: &[u8]) {
+ let len = self.len();
+ let amt = bytes.len();
+ self.vec.reserve(amt);
+
+ unsafe {
+ ptr::copy(self.vec.as_ptr().add(idx), self.vec.as_mut_ptr().add(idx + amt), len - idx);
+ ptr::copy_nonoverlapping(bytes.as_ptr(), self.vec.as_mut_ptr().add(idx), amt);
+ self.vec.set_len(len + amt);
+ }
+ }
+
+ /// Inserts a string slice into this `String` at a byte position.
+ ///
+ /// This is an *O*(*n*) operation as it requires copying every element in the
+ /// buffer.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `idx` is larger than the `String`'s length, or if it does not
+ /// lie on a [`char`] boundary.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("bar");
+ ///
+ /// s.insert_str(0, "foo");
+ ///
+ /// assert_eq!("foobar", s);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "insert_str", since = "1.16.0")]
+ pub fn insert_str(&mut self, idx: usize, string: &str) {
+ assert!(self.is_char_boundary(idx));
+
+ unsafe {
+ self.insert_bytes(idx, string.as_bytes());
+ }
+ }
+
+ /// Returns a mutable reference to the contents of this `String`.
+ ///
+ /// # Safety
+ ///
+ /// This function is unsafe because the returned `&mut Vec` allows writing
+ /// bytes which are not valid UTF-8. If this constraint is violated, using
+ /// the original `String` after dropping the `&mut Vec` may violate memory
+ /// safety, as the rest of the standard library assumes that `String`s are
+ /// valid UTF-8.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("hello");
+ ///
+ /// unsafe {
+ /// let vec = s.as_mut_vec();
+ /// assert_eq!(&[104, 101, 108, 108, 111][..], &vec[..]);
+ ///
+ /// vec.reverse();
+ /// }
+ /// assert_eq!(s, "olleh");
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub unsafe fn as_mut_vec(&mut self) -> &mut Vec<u8> {
+ &mut self.vec
+ }
+
+ /// Returns the length of this `String`, in bytes, not [`char`]s or
+ /// graphemes. In other words, it might not be what a human considers the
+ /// length of the string.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let a = String::from("foo");
+ /// assert_eq!(a.len(), 3);
+ ///
+ /// let fancy_f = String::from("ƒoo");
+ /// assert_eq!(fancy_f.len(), 4);
+ /// assert_eq!(fancy_f.chars().count(), 3);
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn len(&self) -> usize {
+ self.vec.len()
+ }
+
+ /// Returns `true` if this `String` has a length of zero, and `false` otherwise.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut v = String::new();
+ /// assert!(v.is_empty());
+ ///
+ /// v.push('a');
+ /// assert!(!v.is_empty());
+ /// ```
+ #[inline]
+ #[must_use]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Splits the string into two at the given byte index.
+ ///
+ /// Returns a newly allocated `String`. `self` contains bytes `[0, at)`, and
+ /// the returned `String` contains bytes `[at, len)`. `at` must be on the
+ /// boundary of a UTF-8 code point.
+ ///
+ /// Note that the capacity of `self` does not change.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `at` is not on a `UTF-8` code point boundary, or if it is beyond the last
+ /// code point of the string.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # fn main() {
+ /// let mut hello = String::from("Hello, World!");
+ /// let world = hello.split_off(7);
+ /// assert_eq!(hello, "Hello, ");
+ /// assert_eq!(world, "World!");
+ /// # }
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "string_split_off", since = "1.16.0")]
+ #[must_use = "use `.truncate()` if you don't need the other half"]
+ pub fn split_off(&mut self, at: usize) -> String {
+ assert!(self.is_char_boundary(at));
+ let other = self.vec.split_off(at);
+ unsafe { String::from_utf8_unchecked(other) }
+ }
+
+ /// Truncates this `String`, removing all contents.
+ ///
+ /// While this means the `String` will have a length of zero, it does not
+ /// touch its capacity.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("foo");
+ ///
+ /// s.clear();
+ ///
+ /// assert!(s.is_empty());
+ /// assert_eq!(0, s.len());
+ /// assert_eq!(3, s.capacity());
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn clear(&mut self) {
+ self.vec.clear()
+ }
+
+ /// Removes the specified range from the string in bulk, returning all
+ /// removed characters as an iterator.
+ ///
+ /// The returned iterator keeps a mutable borrow on the string to optimize
+ /// its implementation.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point or end point do not lie on a [`char`]
+ /// boundary, or if they're out of bounds.
+ ///
+ /// # Leaking
+ ///
+ /// If the returned iterator goes out of scope without being dropped (due to
+ /// [`core::mem::forget`], for example), the string may still contain a copy
+ /// of any drained characters, or may have lost characters arbitrarily,
+ /// including characters outside the range.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("α is alpha, β is beta");
+ /// let beta_offset = s.find('β').unwrap_or(s.len());
+ ///
+ /// // Remove the range up until the β from the string
+ /// let t: String = s.drain(..beta_offset).collect();
+ /// assert_eq!(t, "α is alpha, ");
+ /// assert_eq!(s, "β is beta");
+ ///
+ /// // A full range clears the string, like `clear()` does
+ /// s.drain(..);
+ /// assert_eq!(s, "");
+ /// ```
+ #[stable(feature = "drain", since = "1.6.0")]
+ pub fn drain<R>(&mut self, range: R) -> Drain<'_>
+ where
+ R: RangeBounds<usize>,
+ {
+ // Memory safety
+ //
+ // The String version of Drain does not have the memory safety issues
+ // of the vector version. The data is just plain bytes.
+ // Because the range removal happens in Drop, if the Drain iterator is leaked,
+ // the removal will not happen.
+ let Range { start, end } = slice::range(range, ..self.len());
+ assert!(self.is_char_boundary(start));
+ assert!(self.is_char_boundary(end));
+
+ // Take out two simultaneous borrows. The &mut String won't be accessed
+ // until iteration is over, in Drop.
+ let self_ptr = self as *mut _;
+ // SAFETY: `slice::range` and `is_char_boundary` do the appropriate bounds checks.
+ let chars_iter = unsafe { self.get_unchecked(start..end) }.chars();
+
+ Drain { start, end, iter: chars_iter, string: self_ptr }
+ }
+
+ /// Removes the specified range in the string,
+ /// and replaces it with the given string.
+ /// The given string doesn't need to be the same length as the range.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point or end point do not lie on a [`char`]
+ /// boundary, or if they're out of bounds.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let mut s = String::from("α is alpha, β is beta");
+ /// let beta_offset = s.find('β').unwrap_or(s.len());
+ ///
+ /// // Replace the range up until the β from the string
+ /// s.replace_range(..beta_offset, "Α is capital alpha; ");
+ /// assert_eq!(s, "Α is capital alpha; β is beta");
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "splice", since = "1.27.0")]
+ pub fn replace_range<R>(&mut self, range: R, replace_with: &str)
+ where
+ R: RangeBounds<usize>,
+ {
+ // Memory safety
+ //
+ // Replace_range does not have the memory safety issues of a vector Splice.
+ // of the vector version. The data is just plain bytes.
+
+ // WARNING: Inlining this variable would be unsound (#81138)
+ let start = range.start_bound();
+ match start {
+ Included(&n) => assert!(self.is_char_boundary(n)),
+ Excluded(&n) => assert!(self.is_char_boundary(n + 1)),
+ Unbounded => {}
+ };
+ // WARNING: Inlining this variable would be unsound (#81138)
+ let end = range.end_bound();
+ match end {
+ Included(&n) => assert!(self.is_char_boundary(n + 1)),
+ Excluded(&n) => assert!(self.is_char_boundary(n)),
+ Unbounded => {}
+ };
+
+ // Using `range` again would be unsound (#81138)
+ // We assume the bounds reported by `range` remain the same, but
+ // an adversarial implementation could change between calls
+ unsafe { self.as_mut_vec() }.splice((start, end), replace_with.bytes());
+ }
+
+ /// Converts this `String` into a <code>[Box]<[str]></code>.
+ ///
+ /// This will drop any excess capacity.
+ ///
+ /// [str]: prim@str "str"
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s = String::from("hello");
+ ///
+ /// let b = s.into_boxed_str();
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "box_str", since = "1.4.0")]
+ #[must_use = "`self` will be dropped if the result is not used"]
+ #[inline]
+ pub fn into_boxed_str(self) -> Box<str> {
+ let slice = self.vec.into_boxed_slice();
+ unsafe { from_boxed_utf8_unchecked(slice) }
+ }
+}
+
+impl FromUtf8Error {
+ /// Returns a slice of [`u8`]s bytes that were attempted to convert to a `String`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // some invalid bytes, in a vector
+ /// let bytes = vec![0, 159];
+ ///
+ /// let value = String::from_utf8(bytes);
+ ///
+ /// assert_eq!(&[0, 159], value.unwrap_err().as_bytes());
+ /// ```
+ #[must_use]
+ #[stable(feature = "from_utf8_error_as_bytes", since = "1.26.0")]
+ pub fn as_bytes(&self) -> &[u8] {
+ &self.bytes[..]
+ }
+
+ /// Returns the bytes that were attempted to convert to a `String`.
+ ///
+ /// This method is carefully constructed to avoid allocation. It will
+ /// consume the error, moving out the bytes, so that a copy of the bytes
+ /// does not need to be made.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // some invalid bytes, in a vector
+ /// let bytes = vec![0, 159];
+ ///
+ /// let value = String::from_utf8(bytes);
+ ///
+ /// assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());
+ /// ```
+ #[must_use = "`self` will be dropped if the result is not used"]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn into_bytes(self) -> Vec<u8> {
+ self.bytes
+ }
+
+ /// Fetch a `Utf8Error` to get more details about the conversion failure.
+ ///
+ /// The [`Utf8Error`] type provided by [`std::str`] represents an error that may
+ /// occur when converting a slice of [`u8`]s to a [`&str`]. In this sense, it's
+ /// an analogue to `FromUtf8Error`. See its documentation for more details
+ /// on using it.
+ ///
+ /// [`std::str`]: core::str "std::str"
+ /// [`&str`]: prim@str "&str"
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// // some invalid bytes, in a vector
+ /// let bytes = vec![0, 159];
+ ///
+ /// let error = String::from_utf8(bytes).unwrap_err().utf8_error();
+ ///
+ /// // the first byte is invalid here
+ /// assert_eq!(1, error.valid_up_to());
+ /// ```
+ #[must_use]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn utf8_error(&self) -> Utf8Error {
+ self.error
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for FromUtf8Error {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Display::fmt(&self.error, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for FromUtf16Error {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Display::fmt("invalid utf-16: lone surrogate found", f)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Clone for String {
+ fn clone(&self) -> Self {
+ String { vec: self.vec.clone() }
+ }
+
+ fn clone_from(&mut self, source: &Self) {
+ self.vec.clone_from(&source.vec);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl FromIterator<char> for String {
+ fn from_iter<I: IntoIterator<Item = char>>(iter: I) -> String {
+ let mut buf = String::new();
+ buf.extend(iter);
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "string_from_iter_by_ref", since = "1.17.0")]
+impl<'a> FromIterator<&'a char> for String {
+ fn from_iter<I: IntoIterator<Item = &'a char>>(iter: I) -> String {
+ let mut buf = String::new();
+ buf.extend(iter);
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> FromIterator<&'a str> for String {
+ fn from_iter<I: IntoIterator<Item = &'a str>>(iter: I) -> String {
+ let mut buf = String::new();
+ buf.extend(iter);
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_string", since = "1.4.0")]
+impl FromIterator<String> for String {
+ fn from_iter<I: IntoIterator<Item = String>>(iter: I) -> String {
+ let mut iterator = iter.into_iter();
+
+ // Because we're iterating over `String`s, we can avoid at least
+ // one allocation by getting the first string from the iterator
+ // and appending to it all the subsequent strings.
+ match iterator.next() {
+ None => String::new(),
+ Some(mut buf) => {
+ buf.extend(iterator);
+ buf
+ }
+ }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_str2", since = "1.45.0")]
+impl FromIterator<Box<str>> for String {
+ fn from_iter<I: IntoIterator<Item = Box<str>>>(iter: I) -> String {
+ let mut buf = String::new();
+ buf.extend(iter);
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "herd_cows", since = "1.19.0")]
+impl<'a> FromIterator<Cow<'a, str>> for String {
+ fn from_iter<I: IntoIterator<Item = Cow<'a, str>>>(iter: I) -> String {
+ let mut iterator = iter.into_iter();
+
+ // Because we're iterating over CoWs, we can (potentially) avoid at least
+ // one allocation by getting the first item and appending to it all the
+ // subsequent items.
+ match iterator.next() {
+ None => String::new(),
+ Some(cow) => {
+ let mut buf = cow.into_owned();
+ buf.extend(iterator);
+ buf
+ }
+ }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Extend<char> for String {
+ fn extend<I: IntoIterator<Item = char>>(&mut self, iter: I) {
+ let iterator = iter.into_iter();
+ let (lower_bound, _) = iterator.size_hint();
+ self.reserve(lower_bound);
+ iterator.for_each(move |c| self.push(c));
+ }
+
+ #[inline]
+ fn extend_one(&mut self, c: char) {
+ self.push(c);
+ }
+
+ #[inline]
+ fn extend_reserve(&mut self, additional: usize) {
+ self.reserve(additional);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_ref", since = "1.2.0")]
+impl<'a> Extend<&'a char> for String {
+ fn extend<I: IntoIterator<Item = &'a char>>(&mut self, iter: I) {
+ self.extend(iter.into_iter().cloned());
+ }
+
+ #[inline]
+ fn extend_one(&mut self, &c: &'a char) {
+ self.push(c);
+ }
+
+ #[inline]
+ fn extend_reserve(&mut self, additional: usize) {
+ self.reserve(additional);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Extend<&'a str> for String {
+ fn extend<I: IntoIterator<Item = &'a str>>(&mut self, iter: I) {
+ iter.into_iter().for_each(move |s| self.push_str(s));
+ }
+
+ #[inline]
+ fn extend_one(&mut self, s: &'a str) {
+ self.push_str(s);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_str2", since = "1.45.0")]
+impl Extend<Box<str>> for String {
+ fn extend<I: IntoIterator<Item = Box<str>>>(&mut self, iter: I) {
+ iter.into_iter().for_each(move |s| self.push_str(&s));
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_string", since = "1.4.0")]
+impl Extend<String> for String {
+ fn extend<I: IntoIterator<Item = String>>(&mut self, iter: I) {
+ iter.into_iter().for_each(move |s| self.push_str(&s));
+ }
+
+ #[inline]
+ fn extend_one(&mut self, s: String) {
+ self.push_str(&s);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "herd_cows", since = "1.19.0")]
+impl<'a> Extend<Cow<'a, str>> for String {
+ fn extend<I: IntoIterator<Item = Cow<'a, str>>>(&mut self, iter: I) {
+ iter.into_iter().for_each(move |s| self.push_str(&s));
+ }
+
+ #[inline]
+ fn extend_one(&mut self, s: Cow<'a, str>) {
+ self.push_str(&s);
+ }
+}
+
+/// A convenience impl that delegates to the impl for `&str`.
+///
+/// # Examples
+///
+/// ```
+/// assert_eq!(String::from("Hello world").find("world"), Some(6));
+/// ```
+#[unstable(
+ feature = "pattern",
+ reason = "API not fully fleshed out and ready to be stabilized",
+ issue = "27721"
+)]
+impl<'a, 'b> Pattern<'a> for &'b String {
+ type Searcher = <&'b str as Pattern<'a>>::Searcher;
+
+ fn into_searcher(self, haystack: &'a str) -> <&'b str as Pattern<'a>>::Searcher {
+ self[..].into_searcher(haystack)
+ }
+
+ #[inline]
+ fn is_contained_in(self, haystack: &'a str) -> bool {
+ self[..].is_contained_in(haystack)
+ }
+
+ #[inline]
+ fn is_prefix_of(self, haystack: &'a str) -> bool {
+ self[..].is_prefix_of(haystack)
+ }
+
+ #[inline]
+ fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+ self[..].strip_prefix_of(haystack)
+ }
+
+ #[inline]
+ fn is_suffix_of(self, haystack: &'a str) -> bool {
+ self[..].is_suffix_of(haystack)
+ }
+
+ #[inline]
+ fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str> {
+ self[..].strip_suffix_of(haystack)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl PartialEq for String {
+ #[inline]
+ fn eq(&self, other: &String) -> bool {
+ PartialEq::eq(&self[..], &other[..])
+ }
+ #[inline]
+ fn ne(&self, other: &String) -> bool {
+ PartialEq::ne(&self[..], &other[..])
+ }
+}
+
+macro_rules! impl_eq {
+ ($lhs:ty, $rhs: ty) => {
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[allow(unused_lifetimes)]
+ impl<'a, 'b> PartialEq<$rhs> for $lhs {
+ #[inline]
+ fn eq(&self, other: &$rhs) -> bool {
+ PartialEq::eq(&self[..], &other[..])
+ }
+ #[inline]
+ fn ne(&self, other: &$rhs) -> bool {
+ PartialEq::ne(&self[..], &other[..])
+ }
+ }
+
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[allow(unused_lifetimes)]
+ impl<'a, 'b> PartialEq<$lhs> for $rhs {
+ #[inline]
+ fn eq(&self, other: &$lhs) -> bool {
+ PartialEq::eq(&self[..], &other[..])
+ }
+ #[inline]
+ fn ne(&self, other: &$lhs) -> bool {
+ PartialEq::ne(&self[..], &other[..])
+ }
+ }
+ };
+}
+
+impl_eq! { String, str }
+impl_eq! { String, &'a str }
+#[cfg(not(no_global_oom_handling))]
+impl_eq! { Cow<'a, str>, str }
+#[cfg(not(no_global_oom_handling))]
+impl_eq! { Cow<'a, str>, &'b str }
+#[cfg(not(no_global_oom_handling))]
+impl_eq! { Cow<'a, str>, String }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl const Default for String {
+ /// Creates an empty `String`.
+ #[inline]
+ fn default() -> String {
+ String::new()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for String {
+ #[inline]
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Display::fmt(&**self, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for String {
+ #[inline]
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Debug::fmt(&**self, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl hash::Hash for String {
+ #[inline]
+ fn hash<H: hash::Hasher>(&self, hasher: &mut H) {
+ (**self).hash(hasher)
+ }
+}
+
+/// Implements the `+` operator for concatenating two strings.
+///
+/// This consumes the `String` on the left-hand side and re-uses its buffer (growing it if
+/// necessary). This is done to avoid allocating a new `String` and copying the entire contents on
+/// every operation, which would lead to *O*(*n*^2) running time when building an *n*-byte string by
+/// repeated concatenation.
+///
+/// The string on the right-hand side is only borrowed; its contents are copied into the returned
+/// `String`.
+///
+/// # Examples
+///
+/// Concatenating two `String`s takes the first by value and borrows the second:
+///
+/// ```
+/// let a = String::from("hello");
+/// let b = String::from(" world");
+/// let c = a + &b;
+/// // `a` is moved and can no longer be used here.
+/// ```
+///
+/// If you want to keep using the first `String`, you can clone it and append to the clone instead:
+///
+/// ```
+/// let a = String::from("hello");
+/// let b = String::from(" world");
+/// let c = a.clone() + &b;
+/// // `a` is still valid here.
+/// ```
+///
+/// Concatenating `&str` slices can be done by converting the first to a `String`:
+///
+/// ```
+/// let a = "hello";
+/// let b = " world";
+/// let c = a.to_string() + b;
+/// ```
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Add<&str> for String {
+ type Output = String;
+
+ #[inline]
+ fn add(mut self, other: &str) -> String {
+ self.push_str(other);
+ self
+ }
+}
+
+/// Implements the `+=` operator for appending to a `String`.
+///
+/// This has the same behavior as the [`push_str`][String::push_str] method.
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "stringaddassign", since = "1.12.0")]
+impl AddAssign<&str> for String {
+ #[inline]
+ fn add_assign(&mut self, other: &str) {
+ self.push_str(other);
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::Range<usize>> for String {
+ type Output = str;
+
+ #[inline]
+ fn index(&self, index: ops::Range<usize>) -> &str {
+ &self[..][index]
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::RangeTo<usize>> for String {
+ type Output = str;
+
+ #[inline]
+ fn index(&self, index: ops::RangeTo<usize>) -> &str {
+ &self[..][index]
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::RangeFrom<usize>> for String {
+ type Output = str;
+
+ #[inline]
+ fn index(&self, index: ops::RangeFrom<usize>) -> &str {
+ &self[..][index]
+ }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::RangeFull> for String {
+ type Output = str;
+
+ #[inline]
+ fn index(&self, _index: ops::RangeFull) -> &str {
+ unsafe { str::from_utf8_unchecked(&self.vec) }
+ }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::Index<ops::RangeInclusive<usize>> for String {
+ type Output = str;
+
+ #[inline]
+ fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
+ Index::index(&**self, index)
+ }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::Index<ops::RangeToInclusive<usize>> for String {
+ type Output = str;
+
+ #[inline]
+ fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
+ Index::index(&**self, index)
+ }
+}
+
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::Range<usize>> for String {
+ #[inline]
+ fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
+ &mut self[..][index]
+ }
+}
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::RangeTo<usize>> for String {
+ #[inline]
+ fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
+ &mut self[..][index]
+ }
+}
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::RangeFrom<usize>> for String {
+ #[inline]
+ fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
+ &mut self[..][index]
+ }
+}
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::RangeFull> for String {
+ #[inline]
+ fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
+ unsafe { str::from_utf8_unchecked_mut(&mut *self.vec) }
+ }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::IndexMut<ops::RangeInclusive<usize>> for String {
+ #[inline]
+ fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
+ IndexMut::index_mut(&mut **self, index)
+ }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::IndexMut<ops::RangeToInclusive<usize>> for String {
+ #[inline]
+ fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
+ IndexMut::index_mut(&mut **self, index)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Deref for String {
+ type Target = str;
+
+ #[inline]
+ fn deref(&self) -> &str {
+ unsafe { str::from_utf8_unchecked(&self.vec) }
+ }
+}
+
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::DerefMut for String {
+ #[inline]
+ fn deref_mut(&mut self) -> &mut str {
+ unsafe { str::from_utf8_unchecked_mut(&mut *self.vec) }
+ }
+}
+
+/// A type alias for [`Infallible`].
+///
+/// This alias exists for backwards compatibility, and may be eventually deprecated.
+///
+/// [`Infallible`]: core::convert::Infallible "convert::Infallible"
+#[stable(feature = "str_parse_error", since = "1.5.0")]
+pub type ParseError = core::convert::Infallible;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl FromStr for String {
+ type Err = core::convert::Infallible;
+ #[inline]
+ fn from_str(s: &str) -> Result<String, Self::Err> {
+ Ok(String::from(s))
+ }
+}
+
+/// A trait for converting a value to a `String`.
+///
+/// This trait is automatically implemented for any type which implements the
+/// [`Display`] trait. As such, `ToString` shouldn't be implemented directly:
+/// [`Display`] should be implemented instead, and you get the `ToString`
+/// implementation for free.
+///
+/// [`Display`]: fmt::Display
+#[cfg_attr(not(test), rustc_diagnostic_item = "ToString")]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait ToString {
+ /// Converts the given value to a `String`.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let i = 5;
+ /// let five = String::from("5");
+ ///
+ /// assert_eq!(five, i.to_string());
+ /// ```
+ #[rustc_conversion_suggestion]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ fn to_string(&self) -> String;
+}
+
+/// # Panics
+///
+/// In this implementation, the `to_string` method panics
+/// if the `Display` implementation returns an error.
+/// This indicates an incorrect `Display` implementation
+/// since `fmt::Write for String` never returns an error itself.
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Display + ?Sized> ToString for T {
+ // A common guideline is to not inline generic functions. However,
+ // removing `#[inline]` from this method causes non-negligible regressions.
+ // See <https://github.com/rust-lang/rust/pull/74852>, the last attempt
+ // to try to remove it.
+ #[inline]
+ default fn to_string(&self) -> String {
+ let mut buf = String::new();
+ let mut formatter = core::fmt::Formatter::new(&mut buf);
+ // Bypass format_args!() to avoid write_str with zero-length strs
+ fmt::Display::fmt(self, &mut formatter)
+ .expect("a Display implementation returned an error unexpectedly");
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "char_to_string_specialization", since = "1.46.0")]
+impl ToString for char {
+ #[inline]
+ fn to_string(&self) -> String {
+ String::from(self.encode_utf8(&mut [0; 4]))
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "u8_to_string_specialization", since = "1.54.0")]
+impl ToString for u8 {
+ #[inline]
+ fn to_string(&self) -> String {
+ let mut buf = String::with_capacity(3);
+ let mut n = *self;
+ if n >= 10 {
+ if n >= 100 {
+ buf.push((b'0' + n / 100) as char);
+ n %= 100;
+ }
+ buf.push((b'0' + n / 10) as char);
+ n %= 10;
+ }
+ buf.push((b'0' + n) as char);
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "i8_to_string_specialization", since = "1.54.0")]
+impl ToString for i8 {
+ #[inline]
+ fn to_string(&self) -> String {
+ let mut buf = String::with_capacity(4);
+ if self.is_negative() {
+ buf.push('-');
+ }
+ let mut n = self.unsigned_abs();
+ if n >= 10 {
+ if n >= 100 {
+ buf.push('1');
+ n -= 100;
+ }
+ buf.push((b'0' + n / 10) as char);
+ n %= 10;
+ }
+ buf.push((b'0' + n) as char);
+ buf
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "str_to_string_specialization", since = "1.9.0")]
+impl ToString for str {
+ #[inline]
+ fn to_string(&self) -> String {
+ String::from(self)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_to_string_specialization", since = "1.17.0")]
+impl ToString for Cow<'_, str> {
+ #[inline]
+ fn to_string(&self) -> String {
+ self[..].to_owned()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "string_to_string_specialization", since = "1.17.0")]
+impl ToString for String {
+ #[inline]
+ fn to_string(&self) -> String {
+ self.to_owned()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRef<str> for String {
+ #[inline]
+ fn as_ref(&self) -> &str {
+ self
+ }
+}
+
+#[stable(feature = "string_as_mut", since = "1.43.0")]
+impl AsMut<str> for String {
+ #[inline]
+ fn as_mut(&mut self) -> &mut str {
+ self
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRef<[u8]> for String {
+ #[inline]
+ fn as_ref(&self) -> &[u8] {
+ self.as_bytes()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl From<&str> for String {
+ /// Converts a `&str` into a [`String`].
+ ///
+ /// The result is allocated on the heap.
+ #[inline]
+ fn from(s: &str) -> String {
+ s.to_owned()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_mut_str_for_string", since = "1.44.0")]
+impl From<&mut str> for String {
+ /// Converts a `&mut str` into a [`String`].
+ ///
+ /// The result is allocated on the heap.
+ #[inline]
+ fn from(s: &mut str) -> String {
+ s.to_owned()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_ref_string", since = "1.35.0")]
+impl From<&String> for String {
+ /// Converts a `&String` into a [`String`].
+ ///
+ /// This clones `s` and returns the clone.
+ #[inline]
+ fn from(s: &String) -> String {
+ s.clone()
+ }
+}
+
+// note: test pulls in libstd, which causes errors here
+#[cfg(not(test))]
+#[stable(feature = "string_from_box", since = "1.18.0")]
+impl From<Box<str>> for String {
+ /// Converts the given boxed `str` slice to a [`String`].
+ /// It is notable that the `str` slice is owned.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s1: String = String::from("hello world");
+ /// let s2: Box<str> = s1.into_boxed_str();
+ /// let s3: String = String::from(s2);
+ ///
+ /// assert_eq!("hello world", s3)
+ /// ```
+ fn from(s: Box<str>) -> String {
+ s.into_string()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_str", since = "1.20.0")]
+impl From<String> for Box<str> {
+ /// Converts the given [`String`] to a boxed `str` slice that is owned.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s1: String = String::from("hello world");
+ /// let s2: Box<str> = Box::from(s1);
+ /// let s3: String = String::from(s2);
+ ///
+ /// assert_eq!("hello world", s3)
+ /// ```
+ fn from(s: String) -> Box<str> {
+ s.into_boxed_str()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "string_from_cow_str", since = "1.14.0")]
+impl<'a> From<Cow<'a, str>> for String {
+ /// Converts a clone-on-write string to an owned
+ /// instance of [`String`].
+ ///
+ /// This extracts the owned string,
+ /// clones the string if it is not already owned.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// # use std::borrow::Cow;
+ /// // If the string is not owned...
+ /// let cow: Cow<str> = Cow::Borrowed("eggplant");
+ /// // It will allocate on the heap and copy the string.
+ /// let owned: String = String::from(cow);
+ /// assert_eq!(&owned[..], "eggplant");
+ /// ```
+ fn from(s: Cow<'a, str>) -> String {
+ s.into_owned()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> From<&'a str> for Cow<'a, str> {
+ /// Converts a string slice into a [`Borrowed`] variant.
+ /// No heap allocation is performed, and the string
+ /// is not copied.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// # use std::borrow::Cow;
+ /// assert_eq!(Cow::from("eggplant"), Cow::Borrowed("eggplant"));
+ /// ```
+ ///
+ /// [`Borrowed`]: crate::borrow::Cow::Borrowed "borrow::Cow::Borrowed"
+ #[inline]
+ fn from(s: &'a str) -> Cow<'a, str> {
+ Cow::Borrowed(s)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> From<String> for Cow<'a, str> {
+ /// Converts a [`String`] into an [`Owned`] variant.
+ /// No heap allocation is performed, and the string
+ /// is not copied.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// # use std::borrow::Cow;
+ /// let s = "eggplant".to_string();
+ /// let s2 = "eggplant".to_string();
+ /// assert_eq!(Cow::from(s), Cow::<'static, str>::Owned(s2));
+ /// ```
+ ///
+ /// [`Owned`]: crate::borrow::Cow::Owned "borrow::Cow::Owned"
+ #[inline]
+ fn from(s: String) -> Cow<'a, str> {
+ Cow::Owned(s)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_from_string_ref", since = "1.28.0")]
+impl<'a> From<&'a String> for Cow<'a, str> {
+ /// Converts a [`String`] reference into a [`Borrowed`] variant.
+ /// No heap allocation is performed, and the string
+ /// is not copied.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// # use std::borrow::Cow;
+ /// let s = "eggplant".to_string();
+ /// assert_eq!(Cow::from(&s), Cow::Borrowed("eggplant"));
+ /// ```
+ ///
+ /// [`Borrowed`]: crate::borrow::Cow::Borrowed "borrow::Cow::Borrowed"
+ #[inline]
+ fn from(s: &'a String) -> Cow<'a, str> {
+ Cow::Borrowed(s.as_str())
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_from_iter", since = "1.12.0")]
+impl<'a> FromIterator<char> for Cow<'a, str> {
+ fn from_iter<I: IntoIterator<Item = char>>(it: I) -> Cow<'a, str> {
+ Cow::Owned(FromIterator::from_iter(it))
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_from_iter", since = "1.12.0")]
+impl<'a, 'b> FromIterator<&'b str> for Cow<'a, str> {
+ fn from_iter<I: IntoIterator<Item = &'b str>>(it: I) -> Cow<'a, str> {
+ Cow::Owned(FromIterator::from_iter(it))
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_from_iter", since = "1.12.0")]
+impl<'a> FromIterator<String> for Cow<'a, str> {
+ fn from_iter<I: IntoIterator<Item = String>>(it: I) -> Cow<'a, str> {
+ Cow::Owned(FromIterator::from_iter(it))
+ }
+}
+
+#[stable(feature = "from_string_for_vec_u8", since = "1.14.0")]
+impl From<String> for Vec<u8> {
+ /// Converts the given [`String`] to a vector [`Vec`] that holds values of type [`u8`].
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// ```
+ /// let s1 = String::from("hello world");
+ /// let v1 = Vec::from(s1);
+ ///
+ /// for b in v1 {
+ /// println!("{}", b);
+ /// }
+ /// ```
+ fn from(string: String) -> Vec<u8> {
+ string.into_bytes()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Write for String {
+ #[inline]
+ fn write_str(&mut self, s: &str) -> fmt::Result {
+ self.push_str(s);
+ Ok(())
+ }
+
+ #[inline]
+ fn write_char(&mut self, c: char) -> fmt::Result {
+ self.push(c);
+ Ok(())
+ }
+}
+
+/// A draining iterator for `String`.
+///
+/// This struct is created by the [`drain`] method on [`String`]. See its
+/// documentation for more.
+///
+/// [`drain`]: String::drain
+#[stable(feature = "drain", since = "1.6.0")]
+pub struct Drain<'a> {
+ /// Will be used as &'a mut String in the destructor
+ string: *mut String,
+ /// Start of part to remove
+ start: usize,
+ /// End of part to remove
+ end: usize,
+ /// Current remaining range to remove
+ iter: Chars<'a>,
+}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl fmt::Debug for Drain<'_> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_tuple("Drain").field(&self.as_str()).finish()
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl Sync for Drain<'_> {}
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl Send for Drain<'_> {}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl Drop for Drain<'_> {
+ fn drop(&mut self) {
+ unsafe {
+ // Use Vec::drain. "Reaffirm" the bounds checks to avoid
+ // panic code being inserted again.
+ let self_vec = (*self.string).as_mut_vec();
+ if self.start <= self.end && self.end <= self_vec.len() {
+ self_vec.drain(self.start..self.end);
+ }
+ }
+ }
+}
+
+impl<'a> Drain<'a> {
+ /// Returns the remaining (sub)string of this iterator as a slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut s = String::from("abc");
+ /// let mut drain = s.drain(..);
+ /// assert_eq!(drain.as_str(), "abc");
+ /// let _ = drain.next().unwrap();
+ /// assert_eq!(drain.as_str(), "bc");
+ /// ```
+ #[must_use]
+ #[stable(feature = "string_drain_as_str", since = "1.55.0")]
+ pub fn as_str(&self) -> &str {
+ self.iter.as_str()
+ }
+}
+
+#[stable(feature = "string_drain_as_str", since = "1.55.0")]
+impl<'a> AsRef<str> for Drain<'a> {
+ fn as_ref(&self) -> &str {
+ self.as_str()
+ }
+}
+
+#[stable(feature = "string_drain_as_str", since = "1.55.0")]
+impl<'a> AsRef<[u8]> for Drain<'a> {
+ fn as_ref(&self) -> &[u8] {
+ self.as_str().as_bytes()
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl Iterator for Drain<'_> {
+ type Item = char;
+
+ #[inline]
+ fn next(&mut self) -> Option<char> {
+ self.iter.next()
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+
+ #[inline]
+ fn last(mut self) -> Option<char> {
+ self.next_back()
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl DoubleEndedIterator for Drain<'_> {
+ #[inline]
+ fn next_back(&mut self) -> Option<char> {
+ self.iter.next_back()
+ }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl FusedIterator for Drain<'_> {}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_char_for_string", since = "1.46.0")]
+impl From<char> for String {
+ /// Allocates an owned [`String`] from a single character.
+ ///
+ /// # Example
+ /// ```rust
+ /// let c: char = 'a';
+ /// let s: String = String::from(c);
+ /// assert_eq!("a", &s[..]);
+ /// ```
+ #[inline]
+ fn from(c: char) -> Self {
+ c.to_string()
+ }
+}
diff --git a/rust/alloc/vec/drain.rs b/rust/alloc/vec/drain.rs
new file mode 100644
index 000000000000..1bff19d05c10
--- /dev/null
+++ b/rust/alloc/vec/drain.rs
@@ -0,0 +1,184 @@
+use crate::alloc::{Allocator, Global};
+use core::fmt;
+use core::iter::{FusedIterator, TrustedLen};
+use core::mem;
+use core::ptr::{self, NonNull};
+use core::slice::{self};
+
+use super::Vec;
+
+/// A draining iterator for `Vec<T>`.
+///
+/// This `struct` is created by [`Vec::drain`].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// let mut v = vec![0, 1, 2];
+/// let iter: std::vec::Drain<_> = v.drain(..);
+/// ```
+#[stable(feature = "drain", since = "1.6.0")]
+pub struct Drain<
+ 'a,
+ T: 'a,
+ #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + 'a = Global,
+> {
+ /// Index of tail to preserve
+ pub(super) tail_start: usize,
+ /// Length of tail
+ pub(super) tail_len: usize,
+ /// Current remaining range to remove
+ pub(super) iter: slice::Iter<'a, T>,
+ pub(super) vec: NonNull<Vec<T, A>>,
+}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl<T: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, T, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_tuple("Drain").field(&self.iter.as_slice()).finish()
+ }
+}
+
+impl<'a, T, A: Allocator> Drain<'a, T, A> {
+ /// Returns the remaining items of this iterator as a slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec!['a', 'b', 'c'];
+ /// let mut drain = vec.drain(..);
+ /// assert_eq!(drain.as_slice(), &['a', 'b', 'c']);
+ /// let _ = drain.next().unwrap();
+ /// assert_eq!(drain.as_slice(), &['b', 'c']);
+ /// ```
+ #[must_use]
+ #[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
+ pub fn as_slice(&self) -> &[T] {
+ self.iter.as_slice()
+ }
+
+ /// Returns a reference to the underlying allocator.
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[must_use]
+ #[inline]
+ pub fn allocator(&self) -> &A {
+ unsafe { self.vec.as_ref().allocator() }
+ }
+}
+
+#[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
+impl<'a, T, A: Allocator> AsRef<[T]> for Drain<'a, T, A> {
+ fn as_ref(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl<T: Sync, A: Sync + Allocator> Sync for Drain<'_, T, A> {}
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl<T: Send, A: Send + Allocator> Send for Drain<'_, T, A> {}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> Iterator for Drain<'_, T, A> {
+ type Item = T;
+
+ #[inline]
+ fn next(&mut self) -> Option<T> {
+ self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) })
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ self.iter.size_hint()
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> DoubleEndedIterator for Drain<'_, T, A> {
+ #[inline]
+ fn next_back(&mut self) -> Option<T> {
+ self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) })
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> Drop for Drain<'_, T, A> {
+ fn drop(&mut self) {
+ /// Moves back the un-`Drain`ed elements to restore the original `Vec`.
+ struct DropGuard<'r, 'a, T, A: Allocator>(&'r mut Drain<'a, T, A>);
+
+ impl<'r, 'a, T, A: Allocator> Drop for DropGuard<'r, 'a, T, A> {
+ fn drop(&mut self) {
+ if self.0.tail_len > 0 {
+ unsafe {
+ let source_vec = self.0.vec.as_mut();
+ // memmove back untouched tail, update to new length
+ let start = source_vec.len();
+ let tail = self.0.tail_start;
+ if tail != start {
+ let src = source_vec.as_ptr().add(tail);
+ let dst = source_vec.as_mut_ptr().add(start);
+ ptr::copy(src, dst, self.0.tail_len);
+ }
+ source_vec.set_len(start + self.0.tail_len);
+ }
+ }
+ }
+ }
+
+ let iter = mem::replace(&mut self.iter, (&mut []).iter());
+ let drop_len = iter.len();
+
+ let mut vec = self.vec;
+
+ if mem::size_of::<T>() == 0 {
+ // ZSTs have no identity, so we don't need to move them around, we only need to drop the correct amount.
+ // this can be achieved by manipulating the Vec length instead of moving values out from `iter`.
+ unsafe {
+ let vec = vec.as_mut();
+ let old_len = vec.len();
+ vec.set_len(old_len + drop_len + self.tail_len);
+ vec.truncate(old_len + self.tail_len);
+ }
+
+ return;
+ }
+
+ // ensure elements are moved back into their appropriate places, even when drop_in_place panics
+ let _guard = DropGuard(self);
+
+ if drop_len == 0 {
+ return;
+ }
+
+ // as_slice() must only be called when iter.len() is > 0 because
+ // vec::Splice modifies vec::Drain fields and may grow the vec which would invalidate
+ // the iterator's internal pointers. Creating a reference to deallocated memory
+ // is invalid even when it is zero-length
+ let drop_ptr = iter.as_slice().as_ptr();
+
+ unsafe {
+ // drop_ptr comes from a slice::Iter which only gives us a &[T] but for drop_in_place
+ // a pointer with mutable provenance is necessary. Therefore we must reconstruct
+ // it from the original vec but also avoid creating a &mut to the front since that could
+ // invalidate raw pointers to it which some unsafe code might rely on.
+ let vec_ptr = vec.as_mut().as_mut_ptr();
+ let drop_offset = drop_ptr.offset_from(vec_ptr) as usize;
+ let to_drop = ptr::slice_from_raw_parts_mut(vec_ptr.add(drop_offset), drop_len);
+ ptr::drop_in_place(to_drop);
+ }
+ }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> ExactSizeIterator for Drain<'_, T, A> {
+ fn is_empty(&self) -> bool {
+ self.iter.is_empty()
+ }
+}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<T, A: Allocator> TrustedLen for Drain<'_, T, A> {}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T, A: Allocator> FusedIterator for Drain<'_, T, A> {}
diff --git a/rust/alloc/vec/drain_filter.rs b/rust/alloc/vec/drain_filter.rs
new file mode 100644
index 000000000000..3c37c92ae44b
--- /dev/null
+++ b/rust/alloc/vec/drain_filter.rs
@@ -0,0 +1,143 @@
+use crate::alloc::{Allocator, Global};
+use core::ptr::{self};
+use core::slice::{self};
+
+use super::Vec;
+
+/// An iterator which uses a closure to determine if an element should be removed.
+///
+/// This struct is created by [`Vec::drain_filter`].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// #![feature(drain_filter)]
+///
+/// let mut v = vec![0, 1, 2];
+/// let iter: std::vec::DrainFilter<_, _> = v.drain_filter(|x| *x % 2 == 0);
+/// ```
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+#[derive(Debug)]
+pub struct DrainFilter<
+ 'a,
+ T,
+ F,
+ #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+> where
+ F: FnMut(&mut T) -> bool,
+{
+ pub(super) vec: &'a mut Vec<T, A>,
+ /// The index of the item that will be inspected by the next call to `next`.
+ pub(super) idx: usize,
+ /// The number of items that have been drained (removed) thus far.
+ pub(super) del: usize,
+ /// The original length of `vec` prior to draining.
+ pub(super) old_len: usize,
+ /// The filter test predicate.
+ pub(super) pred: F,
+ /// A flag that indicates a panic has occurred in the filter test predicate.
+ /// This is used as a hint in the drop implementation to prevent consumption
+ /// of the remainder of the `DrainFilter`. Any unprocessed items will be
+ /// backshifted in the `vec`, but no further items will be dropped or
+ /// tested by the filter predicate.
+ pub(super) panic_flag: bool,
+}
+
+impl<T, F, A: Allocator> DrainFilter<'_, T, F, A>
+where
+ F: FnMut(&mut T) -> bool,
+{
+ /// Returns a reference to the underlying allocator.
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn allocator(&self) -> &A {
+ self.vec.allocator()
+ }
+}
+
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Iterator for DrainFilter<'_, T, F, A>
+where
+ F: FnMut(&mut T) -> bool,
+{
+ type Item = T;
+
+ fn next(&mut self) -> Option<T> {
+ unsafe {
+ while self.idx < self.old_len {
+ let i = self.idx;
+ let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len);
+ self.panic_flag = true;
+ let drained = (self.pred)(&mut v[i]);
+ self.panic_flag = false;
+ // Update the index *after* the predicate is called. If the index
+ // is updated prior and the predicate panics, the element at this
+ // index would be leaked.
+ self.idx += 1;
+ if drained {
+ self.del += 1;
+ return Some(ptr::read(&v[i]));
+ } else if self.del > 0 {
+ let del = self.del;
+ let src: *const T = &v[i];
+ let dst: *mut T = &mut v[i - del];
+ ptr::copy_nonoverlapping(src, dst, 1);
+ }
+ }
+ None
+ }
+ }
+
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ (0, Some(self.old_len - self.idx))
+ }
+}
+
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Drop for DrainFilter<'_, T, F, A>
+where
+ F: FnMut(&mut T) -> bool,
+{
+ fn drop(&mut self) {
+ struct BackshiftOnDrop<'a, 'b, T, F, A: Allocator>
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ drain: &'b mut DrainFilter<'a, T, F, A>,
+ }
+
+ impl<'a, 'b, T, F, A: Allocator> Drop for BackshiftOnDrop<'a, 'b, T, F, A>
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ fn drop(&mut self) {
+ unsafe {
+ if self.drain.idx < self.drain.old_len && self.drain.del > 0 {
+ // This is a pretty messed up state, and there isn't really an
+ // obviously right thing to do. We don't want to keep trying
+ // to execute `pred`, so we just backshift all the unprocessed
+ // elements and tell the vec that they still exist. The backshift
+ // is required to prevent a double-drop of the last successfully
+ // drained item prior to a panic in the predicate.
+ let ptr = self.drain.vec.as_mut_ptr();
+ let src = ptr.add(self.drain.idx);
+ let dst = src.sub(self.drain.del);
+ let tail_len = self.drain.old_len - self.drain.idx;
+ src.copy_to(dst, tail_len);
+ }
+ self.drain.vec.set_len(self.drain.old_len - self.drain.del);
+ }
+ }
+ }
+
+ let backshift = BackshiftOnDrop { drain: self };
+
+ // Attempt to consume any remaining elements if the filter predicate
+ // has not yet panicked. We'll backshift any remaining elements
+ // whether we've already panicked or if the consumption here panics.
+ if !backshift.drain.panic_flag {
+ backshift.drain.for_each(drop);
+ }
+ }
+}
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
new file mode 100644
index 000000000000..f985fb78465b
--- /dev/null
+++ b/rust/alloc/vec/into_iter.rs
@@ -0,0 +1,354 @@
+use crate::alloc::{Allocator, Global};
+use crate::raw_vec::RawVec;
+use core::fmt;
+use core::intrinsics::arith_offset;
+use core::iter::{
+ FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce,
+};
+use core::marker::PhantomData;
+use core::mem::{self};
+use core::ptr::{self, NonNull};
+use core::slice::{self};
+
+/// An iterator that moves out of a vector.
+///
+/// This `struct` is created by the `into_iter` method on [`Vec`](super::Vec)
+/// (provided by the [`IntoIterator`] trait).
+///
+/// # Example
+///
+/// ```
+/// let v = vec![0, 1, 2];
+/// let iter: std::vec::IntoIter<_> = v.into_iter();
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_insignificant_dtor]
+pub struct IntoIter<
+ T,
+ #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+> {
+ pub(super) buf: NonNull<T>,
+ pub(super) phantom: PhantomData<T>,
+ pub(super) cap: usize,
+ pub(super) alloc: A,
+ pub(super) ptr: *const T,
+ pub(super) end: *const T,
+}
+
+#[stable(feature = "vec_intoiter_debug", since = "1.13.0")]
+impl<T: fmt::Debug, A: Allocator> fmt::Debug for IntoIter<T, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.debug_tuple("IntoIter").field(&self.as_slice()).finish()
+ }
+}
+
+impl<T, A: Allocator> IntoIter<T, A> {
+ /// Returns the remaining items of this iterator as a slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let vec = vec!['a', 'b', 'c'];
+ /// let mut into_iter = vec.into_iter();
+ /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ /// let _ = into_iter.next().unwrap();
+ /// assert_eq!(into_iter.as_slice(), &['b', 'c']);
+ /// ```
+ #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
+ pub fn as_slice(&self) -> &[T] {
+ unsafe { slice::from_raw_parts(self.ptr, self.len()) }
+ }
+
+ /// Returns the remaining items of this iterator as a mutable slice.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let vec = vec!['a', 'b', 'c'];
+ /// let mut into_iter = vec.into_iter();
+ /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+ /// into_iter.as_mut_slice()[2] = 'z';
+ /// assert_eq!(into_iter.next().unwrap(), 'a');
+ /// assert_eq!(into_iter.next().unwrap(), 'b');
+ /// assert_eq!(into_iter.next().unwrap(), 'z');
+ /// ```
+ #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
+ pub fn as_mut_slice(&mut self) -> &mut [T] {
+ unsafe { &mut *self.as_raw_mut_slice() }
+ }
+
+ /// Returns a reference to the underlying allocator.
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn allocator(&self) -> &A {
+ &self.alloc
+ }
+
+ fn as_raw_mut_slice(&mut self) -> *mut [T] {
+ ptr::slice_from_raw_parts_mut(self.ptr as *mut T, self.len())
+ }
+
+ /// Drops remaining elements and relinquishes the backing allocation.
+ ///
+ /// This is roughly equivalent to the following, but more efficient
+ ///
+ /// ```
+ /// # let mut into_iter = Vec::<u8>::with_capacity(10).into_iter();
+ /// (&mut into_iter).for_each(core::mem::drop);
+ /// unsafe { core::ptr::write(&mut into_iter, Vec::new().into_iter()); }
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ pub(super) fn forget_allocation_drop_remaining(&mut self) {
+ let remaining = self.as_raw_mut_slice();
+
+ // overwrite the individual fields instead of creating a new
+ // struct and then overwriting &mut self.
+ // this creates less assembly
+ self.cap = 0;
+ self.buf = unsafe { NonNull::new_unchecked(RawVec::NEW.ptr()) };
+ self.ptr = self.buf.as_ptr();
+ self.end = self.buf.as_ptr();
+
+ unsafe {
+ ptr::drop_in_place(remaining);
+ }
+ }
+}
+
+#[stable(feature = "vec_intoiter_as_ref", since = "1.46.0")]
+impl<T, A: Allocator> AsRef<[T]> for IntoIter<T, A> {
+ fn as_ref(&self) -> &[T] {
+ self.as_slice()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<T: Send, A: Allocator + Send> Send for IntoIter<T, A> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<T: Sync, A: Allocator + Sync> Sync for IntoIter<T, A> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> Iterator for IntoIter<T, A> {
+ type Item = T;
+
+ #[inline]
+ fn next(&mut self) -> Option<T> {
+ if self.ptr as *const _ == self.end {
+ None
+ } else if mem::size_of::<T>() == 0 {
+ // purposefully don't use 'ptr.offset' because for
+ // vectors with 0-size elements this would return the
+ // same pointer.
+ self.ptr = unsafe { arith_offset(self.ptr as *const i8, 1) as *mut T };
+
+ // Make up a value of this ZST.
+ Some(unsafe { mem::zeroed() })
+ } else {
+ let old = self.ptr;
+ self.ptr = unsafe { self.ptr.offset(1) };
+
+ Some(unsafe { ptr::read(old) })
+ }
+ }
+
+ #[inline]
+ fn size_hint(&self) -> (usize, Option<usize>) {
+ let exact = if mem::size_of::<T>() == 0 {
+ (self.end as usize).wrapping_sub(self.ptr as usize)
+ } else {
+ unsafe { self.end.offset_from(self.ptr) as usize }
+ };
+ (exact, Some(exact))
+ }
+
+ #[inline]
+ fn advance_by(&mut self, n: usize) -> Result<(), usize> {
+ let step_size = self.len().min(n);
+ let to_drop = ptr::slice_from_raw_parts_mut(self.ptr as *mut T, step_size);
+ if mem::size_of::<T>() == 0 {
+ // SAFETY: due to unchecked casts of unsigned amounts to signed offsets the wraparound
+ // effectively results in unsigned pointers representing positions 0..usize::MAX,
+ // which is valid for ZSTs.
+ self.ptr = unsafe { arith_offset(self.ptr as *const i8, step_size as isize) as *mut T }
+ } else {
+ // SAFETY: the min() above ensures that step_size is in bounds
+ self.ptr = unsafe { self.ptr.add(step_size) };
+ }
+ // SAFETY: the min() above ensures that step_size is in bounds
+ unsafe {
+ ptr::drop_in_place(to_drop);
+ }
+ if step_size < n {
+ return Err(step_size);
+ }
+ Ok(())
+ }
+
+ #[inline]
+ fn count(self) -> usize {
+ self.len()
+ }
+
+ #[doc(hidden)]
+ unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
+ where
+ Self: TrustedRandomAccessNoCoerce,
+ {
+ // SAFETY: the caller must guarantee that `i` is in bounds of the
+ // `Vec<T>`, so `i` cannot overflow an `isize`, and the `self.ptr.add(i)`
+ // is guaranteed to pointer to an element of the `Vec<T>` and
+ // thus guaranteed to be valid to dereference.
+ //
+ // Also note the implementation of `Self: TrustedRandomAccess` requires
+ // that `T: Copy` so reading elements from the buffer doesn't invalidate
+ // them for `Drop`.
+ unsafe {
+ if mem::size_of::<T>() == 0 { mem::zeroed() } else { ptr::read(self.ptr.add(i)) }
+ }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
+ #[inline]
+ fn next_back(&mut self) -> Option<T> {
+ if self.end == self.ptr {
+ None
+ } else if mem::size_of::<T>() == 0 {
+ // See above for why 'ptr.offset' isn't used
+ self.end = unsafe { arith_offset(self.end as *const i8, -1) as *mut T };
+
+ // Make up a value of this ZST.
+ Some(unsafe { mem::zeroed() })
+ } else {
+ self.end = unsafe { self.end.offset(-1) };
+
+ Some(unsafe { ptr::read(self.end) })
+ }
+ }
+
+ #[inline]
+ fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
+ let step_size = self.len().min(n);
+ if mem::size_of::<T>() == 0 {
+ // SAFETY: same as for advance_by()
+ self.end = unsafe {
+ arith_offset(self.end as *const i8, step_size.wrapping_neg() as isize) as *mut T
+ }
+ } else {
+ // SAFETY: same as for advance_by()
+ self.end = unsafe { self.end.offset(step_size.wrapping_neg() as isize) };
+ }
+ let to_drop = ptr::slice_from_raw_parts_mut(self.end as *mut T, step_size);
+ // SAFETY: same as for advance_by()
+ unsafe {
+ ptr::drop_in_place(to_drop);
+ }
+ if step_size < n {
+ return Err(step_size);
+ }
+ Ok(())
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> ExactSizeIterator for IntoIter<T, A> {
+ fn is_empty(&self) -> bool {
+ self.ptr == self.end
+ }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T, A: Allocator> FusedIterator for IntoIter<T, A> {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<T, A: Allocator> TrustedLen for IntoIter<T, A> {}
+
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "std_internals")]
+#[rustc_unsafe_specialization_marker]
+pub trait NonDrop {}
+
+// T: Copy as approximation for !Drop since get_unchecked does not advance self.ptr
+// and thus we can't implement drop-handling
+#[unstable(issue = "none", feature = "std_internals")]
+impl<T: Copy> NonDrop for T {}
+
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "std_internals")]
+// TrustedRandomAccess (without NoCoerce) must not be implemented because
+// subtypes/supertypes of `T` might not be `NonDrop`
+unsafe impl<T, A: Allocator> TrustedRandomAccessNoCoerce for IntoIter<T, A>
+where
+ T: NonDrop,
+{
+ const MAY_HAVE_SIDE_EFFECT: bool = false;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
+ #[cfg(not(test))]
+ fn clone(&self) -> Self {
+ self.as_slice().to_vec_in(self.alloc.clone()).into_iter()
+ }
+ #[cfg(test)]
+ fn clone(&self) -> Self {
+ crate::slice::to_vec(self.as_slice(), self.alloc.clone()).into_iter()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
+ fn drop(&mut self) {
+ struct DropGuard<'a, T, A: Allocator>(&'a mut IntoIter<T, A>);
+
+ impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
+ fn drop(&mut self) {
+ unsafe {
+ // `IntoIter::alloc` is not used anymore after this
+ let alloc = ptr::read(&self.0.alloc);
+ // RawVec handles deallocation
+ let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
+ }
+ }
+ }
+
+ let guard = DropGuard(self);
+ // destroy the remaining elements
+ unsafe {
+ ptr::drop_in_place(guard.0.as_raw_mut_slice());
+ }
+ // now `guard` will be dropped and do the rest
+ }
+}
+
+#[unstable(issue = "none", feature = "inplace_iteration")]
+#[doc(hidden)]
+unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {}
+
+#[unstable(issue = "none", feature = "inplace_iteration")]
+#[doc(hidden)]
+unsafe impl<T, A: Allocator> SourceIter for IntoIter<T, A> {
+ type Source = Self;
+
+ #[inline]
+ unsafe fn as_inner(&mut self) -> &mut Self::Source {
+ self
+ }
+}
+
+// internal helper trait for in-place iteration specialization.
+#[rustc_specialization_trait]
+pub(crate) trait AsIntoIter {
+ type Item;
+ fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item>;
+}
+
+impl<T> AsIntoIter for IntoIter<T> {
+ type Item = T;
+
+ fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
+ self
+ }
+}
diff --git a/rust/alloc/vec/is_zero.rs b/rust/alloc/vec/is_zero.rs
new file mode 100644
index 000000000000..0efc4893c3c4
--- /dev/null
+++ b/rust/alloc/vec/is_zero.rs
@@ -0,0 +1,104 @@
+use crate::boxed::Box;
+
+#[rustc_specialization_trait]
+pub(super) unsafe trait IsZero {
+ /// Whether this value is zero
+ fn is_zero(&self) -> bool;
+}
+
+macro_rules! impl_is_zero {
+ ($t:ty, $is_zero:expr) => {
+ unsafe impl IsZero for $t {
+ #[inline]
+ fn is_zero(&self) -> bool {
+ $is_zero(*self)
+ }
+ }
+ };
+}
+
+impl_is_zero!(i16, |x| x == 0);
+impl_is_zero!(i32, |x| x == 0);
+impl_is_zero!(i64, |x| x == 0);
+impl_is_zero!(i128, |x| x == 0);
+impl_is_zero!(isize, |x| x == 0);
+
+impl_is_zero!(u16, |x| x == 0);
+impl_is_zero!(u32, |x| x == 0);
+impl_is_zero!(u64, |x| x == 0);
+impl_is_zero!(u128, |x| x == 0);
+impl_is_zero!(usize, |x| x == 0);
+
+impl_is_zero!(bool, |x| x == false);
+impl_is_zero!(char, |x| x == '\0');
+
+impl_is_zero!(f32, |x: f32| x.to_bits() == 0);
+impl_is_zero!(f64, |x: f64| x.to_bits() == 0);
+
+unsafe impl<T> IsZero for *const T {
+ #[inline]
+ fn is_zero(&self) -> bool {
+ (*self).is_null()
+ }
+}
+
+unsafe impl<T> IsZero for *mut T {
+ #[inline]
+ fn is_zero(&self) -> bool {
+ (*self).is_null()
+ }
+}
+
+// `Option<&T>` and `Option<Box<T>>` are guaranteed to represent `None` as null.
+// For fat pointers, the bytes that would be the pointer metadata in the `Some`
+// variant are padding in the `None` variant, so ignoring them and
+// zero-initializing instead is ok.
+// `Option<&mut T>` never implements `Clone`, so there's no need for an impl of
+// `SpecFromElem`.
+
+unsafe impl<T: ?Sized> IsZero for Option<&T> {
+ #[inline]
+ fn is_zero(&self) -> bool {
+ self.is_none()
+ }
+}
+
+unsafe impl<T: ?Sized> IsZero for Option<Box<T>> {
+ #[inline]
+ fn is_zero(&self) -> bool {
+ self.is_none()
+ }
+}
+
+// `Option<num::NonZeroU32>` and similar have a representation guarantee that
+// they're the same size as the corresponding `u32` type, as well as a guarantee
+// that transmuting between `NonZeroU32` and `Option<num::NonZeroU32>` works.
+// While the documentation officially makes it UB to transmute from `None`,
+// we're the standard library so we can make extra inferences, and we know that
+// the only niche available to represent `None` is the one that's all zeros.
+
+macro_rules! impl_is_zero_option_of_nonzero {
+ ($($t:ident,)+) => {$(
+ unsafe impl IsZero for Option<core::num::$t> {
+ #[inline]
+ fn is_zero(&self) -> bool {
+ self.is_none()
+ }
+ }
+ )+};
+}
+
+impl_is_zero_option_of_nonzero!(
+ NonZeroU8,
+ NonZeroU16,
+ NonZeroU32,
+ NonZeroU64,
+ NonZeroU128,
+ NonZeroI8,
+ NonZeroI16,
+ NonZeroI32,
+ NonZeroI64,
+ NonZeroI128,
+ NonZeroUsize,
+ NonZeroIsize,
+);
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
new file mode 100644
index 000000000000..c29aa0fec5b8
--- /dev/null
+++ b/rust/alloc/vec/mod.rs
@@ -0,0 +1,3055 @@
+//! A contiguous growable array type with heap-allocated contents, written
+//! `Vec<T>`.
+//!
+//! Vectors have *O*(1) indexing, amortized *O*(1) push (to the end) and
+//! *O*(1) pop (from the end).
+//!
+//! Vectors ensure they never allocate more than `isize::MAX` bytes.
+//!
+//! # Examples
+//!
+//! You can explicitly create a [`Vec`] with [`Vec::new`]:
+//!
+//! ```
+//! let v: Vec<i32> = Vec::new();
+//! ```
+//!
+//! ...or by using the [`vec!`] macro:
+//!
+//! ```
+//! let v: Vec<i32> = vec![];
+//!
+//! let v = vec![1, 2, 3, 4, 5];
+//!
+//! let v = vec![0; 10]; // ten zeroes
+//! ```
+//!
+//! You can [`push`] values onto the end of a vector (which will grow the vector
+//! as needed):
+//!
+//! ```
+//! let mut v = vec![1, 2];
+//!
+//! v.push(3);
+//! ```
+//!
+//! Popping values works in much the same way:
+//!
+//! ```
+//! let mut v = vec![1, 2];
+//!
+//! let two = v.pop();
+//! ```
+//!
+//! Vectors also support indexing (through the [`Index`] and [`IndexMut`] traits):
+//!
+//! ```
+//! let mut v = vec![1, 2, 3];
+//! let three = v[2];
+//! v[1] = v[1] + 5;
+//! ```
+//!
+//! [`push`]: Vec::push
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[cfg(not(no_global_oom_handling))]
+use core::cmp;
+use core::cmp::Ordering;
+use core::convert::TryFrom;
+use core::fmt;
+use core::hash::{Hash, Hasher};
+use core::intrinsics::{arith_offset, assume};
+use core::iter;
+#[cfg(not(no_global_oom_handling))]
+use core::iter::FromIterator;
+use core::marker::PhantomData;
+use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::ops::{self, Index, IndexMut, Range, RangeBounds};
+use core::ptr::{self, NonNull};
+use core::slice::{self, SliceIndex};
+
+use crate::alloc::{Allocator, Global};
+use crate::borrow::{Cow, ToOwned};
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::raw_vec::RawVec;
+
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+pub use self::drain_filter::DrainFilter;
+
+mod drain_filter;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_splice", since = "1.21.0")]
+pub use self::splice::Splice;
+
+#[cfg(not(no_global_oom_handling))]
+mod splice;
+
+#[stable(feature = "drain", since = "1.6.0")]
+pub use self::drain::Drain;
+
+mod drain;
+
+#[cfg(not(no_global_oom_handling))]
+mod cow;
+
+#[cfg(not(no_global_oom_handling))]
+pub(crate) use self::into_iter::AsIntoIter;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::into_iter::IntoIter;
+
+mod into_iter;
+
+#[cfg(not(no_global_oom_handling))]
+use self::is_zero::IsZero;
+
+mod is_zero;
+
+#[cfg(not(no_global_oom_handling))]
+mod source_iter_marker;
+
+mod partial_eq;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_from_elem::SpecFromElem;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_from_elem;
+
+#[cfg(not(no_global_oom_handling))]
+use self::set_len_on_drop::SetLenOnDrop;
+
+#[cfg(not(no_global_oom_handling))]
+mod set_len_on_drop;
+
+#[cfg(not(no_global_oom_handling))]
+use self::in_place_drop::InPlaceDrop;
+
+#[cfg(not(no_global_oom_handling))]
+mod in_place_drop;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_from_iter_nested::SpecFromIterNested;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_from_iter_nested;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_from_iter::SpecFromIter;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_from_iter;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_extend::SpecExtend;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_extend;
+
+/// A contiguous growable array type, written as `Vec<T>`, short for 'vector'.
+///
+/// # Examples
+///
+/// ```
+/// let mut vec = Vec::new();
+/// vec.push(1);
+/// vec.push(2);
+///
+/// assert_eq!(vec.len(), 2);
+/// assert_eq!(vec[0], 1);
+///
+/// assert_eq!(vec.pop(), Some(2));
+/// assert_eq!(vec.len(), 1);
+///
+/// vec[0] = 7;
+/// assert_eq!(vec[0], 7);
+///
+/// vec.extend([1, 2, 3].iter().copied());
+///
+/// for x in &vec {
+/// println!("{}", x);
+/// }
+/// assert_eq!(vec, [7, 1, 2, 3]);
+/// ```
+///
+/// The [`vec!`] macro is provided for convenient initialization:
+///
+/// ```
+/// let mut vec1 = vec![1, 2, 3];
+/// vec1.push(4);
+/// let vec2 = Vec::from([1, 2, 3, 4]);
+/// assert_eq!(vec1, vec2);
+/// ```
+///
+/// It can also initialize each element of a `Vec<T>` with a given value.
+/// This may be more efficient than performing allocation and initialization
+/// in separate steps, especially when initializing a vector of zeros:
+///
+/// ```
+/// let vec = vec![0; 5];
+/// assert_eq!(vec, [0, 0, 0, 0, 0]);
+///
+/// // The following is equivalent, but potentially slower:
+/// let mut vec = Vec::with_capacity(5);
+/// vec.resize(5, 0);
+/// assert_eq!(vec, [0, 0, 0, 0, 0]);
+/// ```
+///
+/// For more information, see
+/// [Capacity and Reallocation](#capacity-and-reallocation).
+///
+/// Use a `Vec<T>` as an efficient stack:
+///
+/// ```
+/// let mut stack = Vec::new();
+///
+/// stack.push(1);
+/// stack.push(2);
+/// stack.push(3);
+///
+/// while let Some(top) = stack.pop() {
+/// // Prints 3, 2, 1
+/// println!("{}", top);
+/// }
+/// ```
+///
+/// # Indexing
+///
+/// The `Vec` type allows to access values by index, because it implements the
+/// [`Index`] trait. An example will be more explicit:
+///
+/// ```
+/// let v = vec![0, 2, 4, 6];
+/// println!("{}", v[1]); // it will display '2'
+/// ```
+///
+/// However be careful: if you try to access an index which isn't in the `Vec`,
+/// your software will panic! You cannot do this:
+///
+/// ```should_panic
+/// let v = vec![0, 2, 4, 6];
+/// println!("{}", v[6]); // it will panic!
+/// ```
+///
+/// Use [`get`] and [`get_mut`] if you want to check whether the index is in
+/// the `Vec`.
+///
+/// # Slicing
+///
+/// A `Vec` can be mutable. On the other hand, slices are read-only objects.
+/// To get a [slice][prim@slice], use [`&`]. Example:
+///
+/// ```
+/// fn read_slice(slice: &[usize]) {
+/// // ...
+/// }
+///
+/// let v = vec![0, 1];
+/// read_slice(&v);
+///
+/// // ... and that's all!
+/// // you can also do it like this:
+/// let u: &[usize] = &v;
+/// // or like this:
+/// let u: &[_] = &v;
+/// ```
+///
+/// In Rust, it's more common to pass slices as arguments rather than vectors
+/// when you just want to provide read access. The same goes for [`String`] and
+/// [`&str`].
+///
+/// # Capacity and reallocation
+///
+/// The capacity of a vector is the amount of space allocated for any future
+/// elements that will be added onto the vector. This is not to be confused with
+/// the *length* of a vector, which specifies the number of actual elements
+/// within the vector. If a vector's length exceeds its capacity, its capacity
+/// will automatically be increased, but its elements will have to be
+/// reallocated.
+///
+/// For example, a vector with capacity 10 and length 0 would be an empty vector
+/// with space for 10 more elements. Pushing 10 or fewer elements onto the
+/// vector will not change its capacity or cause reallocation to occur. However,
+/// if the vector's length is increased to 11, it will have to reallocate, which
+/// can be slow. For this reason, it is recommended to use [`Vec::with_capacity`]
+/// whenever possible to specify how big the vector is expected to get.
+///
+/// # Guarantees
+///
+/// Due to its incredibly fundamental nature, `Vec` makes a lot of guarantees
+/// about its design. This ensures that it's as low-overhead as possible in
+/// the general case, and can be correctly manipulated in primitive ways
+/// by unsafe code. Note that these guarantees refer to an unqualified `Vec<T>`.
+/// If additional type parameters are added (e.g., to support custom allocators),
+/// overriding their defaults may change the behavior.
+///
+/// Most fundamentally, `Vec` is and always will be a (pointer, capacity, length)
+/// triplet. No more, no less. The order of these fields is completely
+/// unspecified, and you should use the appropriate methods to modify these.
+/// The pointer will never be null, so this type is null-pointer-optimized.
+///
+/// However, the pointer might not actually point to allocated memory. In particular,
+/// if you construct a `Vec` with capacity 0 via [`Vec::new`], [`vec![]`][`vec!`],
+/// [`Vec::with_capacity(0)`][`Vec::with_capacity`], or by calling [`shrink_to_fit`]
+/// on an empty Vec, it will not allocate memory. Similarly, if you store zero-sized
+/// types inside a `Vec`, it will not allocate space for them. *Note that in this case
+/// the `Vec` might not report a [`capacity`] of 0*. `Vec` will allocate if and only
+/// if <code>[mem::size_of::\<T>]\() * [capacity]\() > 0</code>. In general, `Vec`'s allocation
+/// details are very subtle --- if you intend to allocate memory using a `Vec`
+/// and use it for something else (either to pass to unsafe code, or to build your
+/// own memory-backed collection), be sure to deallocate this memory by using
+/// `from_raw_parts` to recover the `Vec` and then dropping it.
+///
+/// If a `Vec` *has* allocated memory, then the memory it points to is on the heap
+/// (as defined by the allocator Rust is configured to use by default), and its
+/// pointer points to [`len`] initialized, contiguous elements in order (what
+/// you would see if you coerced it to a slice), followed by <code>[capacity] - [len]</code>
+/// logically uninitialized, contiguous elements.
+///
+/// A vector containing the elements `'a'` and `'b'` with capacity 4 can be
+/// visualized as below. The top part is the `Vec` struct, it contains a
+/// pointer to the head of the allocation in the heap, length and capacity.
+/// The bottom part is the allocation on the heap, a contiguous memory block.
+///
+/// ```text
+/// ptr len capacity
+/// +--------+--------+--------+
+/// | 0x0123 | 2 | 4 |
+/// +--------+--------+--------+
+/// |
+/// v
+/// Heap +--------+--------+--------+--------+
+/// | 'a' | 'b' | uninit | uninit |
+/// +--------+--------+--------+--------+
+/// ```
+///
+/// - **uninit** represents memory that is not initialized, see [`MaybeUninit`].
+/// - Note: the ABI is not stable and `Vec` makes no guarantees about its memory
+/// layout (including the order of fields).
+///
+/// `Vec` will never perform a "small optimization" where elements are actually
+/// stored on the stack for two reasons:
+///
+/// * It would make it more difficult for unsafe code to correctly manipulate
+/// a `Vec`. The contents of a `Vec` wouldn't have a stable address if it were
+/// only moved, and it would be more difficult to determine if a `Vec` had
+/// actually allocated memory.
+///
+/// * It would penalize the general case, incurring an additional branch
+/// on every access.
+///
+/// `Vec` will never automatically shrink itself, even if completely empty. This
+/// ensures no unnecessary allocations or deallocations occur. Emptying a `Vec`
+/// and then filling it back up to the same [`len`] should incur no calls to
+/// the allocator. If you wish to free up unused memory, use
+/// [`shrink_to_fit`] or [`shrink_to`].
+///
+/// [`push`] and [`insert`] will never (re)allocate if the reported capacity is
+/// sufficient. [`push`] and [`insert`] *will* (re)allocate if
+/// <code>[len] == [capacity]</code>. That is, the reported capacity is completely
+/// accurate, and can be relied on. It can even be used to manually free the memory
+/// allocated by a `Vec` if desired. Bulk insertion methods *may* reallocate, even
+/// when not necessary.
+///
+/// `Vec` does not guarantee any particular growth strategy when reallocating
+/// when full, nor when [`reserve`] is called. The current strategy is basic
+/// and it may prove desirable to use a non-constant growth factor. Whatever
+/// strategy is used will of course guarantee *O*(1) amortized [`push`].
+///
+/// `vec![x; n]`, `vec![a, b, c, d]`, and
+/// [`Vec::with_capacity(n)`][`Vec::with_capacity`], will all produce a `Vec`
+/// with exactly the requested capacity. If <code>[len] == [capacity]</code>,
+/// (as is the case for the [`vec!`] macro), then a `Vec<T>` can be converted to
+/// and from a [`Box<[T]>`][owned slice] without reallocating or moving the elements.
+///
+/// `Vec` will not specifically overwrite any data that is removed from it,
+/// but also won't specifically preserve it. Its uninitialized memory is
+/// scratch space that it may use however it wants. It will generally just do
+/// whatever is most efficient or otherwise easy to implement. Do not rely on
+/// removed data to be erased for security purposes. Even if you drop a `Vec`, its
+/// buffer may simply be reused by another allocation. Even if you zero a `Vec`'s memory
+/// first, that might not actually happen because the optimizer does not consider
+/// this a side-effect that must be preserved. There is one case which we will
+/// not break, however: using `unsafe` code to write to the excess capacity,
+/// and then increasing the length to match, is always valid.
+///
+/// Currently, `Vec` does not guarantee the order in which elements are dropped.
+/// The order has changed in the past and may change again.
+///
+/// [`get`]: ../../std/vec/struct.Vec.html#method.get
+/// [`get_mut`]: ../../std/vec/struct.Vec.html#method.get_mut
+/// [`String`]: crate::string::String
+/// [`&str`]: type@str
+/// [`shrink_to_fit`]: Vec::shrink_to_fit
+/// [`shrink_to`]: Vec::shrink_to
+/// [capacity]: Vec::capacity
+/// [`capacity`]: Vec::capacity
+/// [mem::size_of::\<T>]: core::mem::size_of
+/// [len]: Vec::len
+/// [`len`]: Vec::len
+/// [`push`]: Vec::push
+/// [`insert`]: Vec::insert
+/// [`reserve`]: Vec::reserve
+/// [`MaybeUninit`]: core::mem::MaybeUninit
+/// [owned slice]: Box
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Vec")]
+#[rustc_insignificant_dtor]
+pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
+ buf: RawVec<T, A>,
+ len: usize,
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Inherent methods
+////////////////////////////////////////////////////////////////////////////////
+
+impl<T> Vec<T> {
+ /// Constructs a new, empty `Vec<T>`.
+ ///
+ /// The vector will not allocate until elements are pushed onto it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # #![allow(unused_mut)]
+ /// let mut vec: Vec<i32> = Vec::new();
+ /// ```
+ #[inline]
+ #[rustc_const_stable(feature = "const_vec_new", since = "1.39.0")]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
+ pub const fn new() -> Self {
+ Vec { buf: RawVec::NEW, len: 0 }
+ }
+
+ /// Constructs a new, empty `Vec<T>` with the specified capacity.
+ ///
+ /// The vector will be able to hold exactly `capacity` elements without
+ /// reallocating. If `capacity` is 0, the vector will not allocate.
+ ///
+ /// It is important to note that although the returned vector has the
+ /// *capacity* specified, the vector will have a zero *length*. For an
+ /// explanation of the difference between length and capacity, see
+ /// *[Capacity and reallocation]*.
+ ///
+ /// [Capacity and reallocation]: #capacity-and-reallocation
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ ///
+ /// // The vector contains no items, even though it has capacity for more
+ /// assert_eq!(vec.len(), 0);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // These are all done without reallocating...
+ /// for i in 0..10 {
+ /// vec.push(i);
+ /// }
+ /// assert_eq!(vec.len(), 10);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // ...but this may make the vector reallocate
+ /// vec.push(11);
+ /// assert_eq!(vec.len(), 11);
+ /// assert!(vec.capacity() >= 11);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[must_use]
+ pub fn with_capacity(capacity: usize) -> Self {
+ Self::with_capacity_in(capacity, Global)
+ }
+
+ /// Creates a `Vec<T>` directly from the raw components of another vector.
+ ///
+ /// # Safety
+ ///
+ /// This is highly unsafe, due to the number of invariants that aren't
+ /// checked:
+ ///
+ /// * `ptr` needs to have been previously allocated via [`String`]/`Vec<T>`
+ /// (at least, it's highly likely to be incorrect if it wasn't).
+ /// * `T` needs to have the same size and alignment as what `ptr` was allocated with.
+ /// (`T` having a less strict alignment is not sufficient, the alignment really
+ /// needs to be equal to satisfy the [`dealloc`] requirement that memory must be
+ /// allocated and deallocated with the same layout.)
+ /// * `length` needs to be less than or equal to `capacity`.
+ /// * `capacity` needs to be the capacity that the pointer was allocated with.
+ ///
+ /// Violating these may cause problems like corrupting the allocator's
+ /// internal data structures. For example it is **not** safe
+ /// to build a `Vec<u8>` from a pointer to a C `char` array with length `size_t`.
+ /// It's also not safe to build one from a `Vec<u16>` and its length, because
+ /// the allocator cares about the alignment, and these two types have different
+ /// alignments. The buffer was allocated with alignment 2 (for `u16`), but after
+ /// turning it into a `Vec<u8>` it'll be deallocated with alignment 1.
+ ///
+ /// The ownership of `ptr` is effectively transferred to the
+ /// `Vec<T>` which may then deallocate, reallocate or change the
+ /// contents of memory pointed to by the pointer at will. Ensure
+ /// that nothing else uses the pointer after calling this
+ /// function.
+ ///
+ /// [`String`]: crate::string::String
+ /// [`dealloc`]: crate::alloc::GlobalAlloc::dealloc
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::ptr;
+ /// use std::mem;
+ ///
+ /// let v = vec![1, 2, 3];
+ ///
+ // FIXME Update this when vec_into_raw_parts is stabilized
+ /// // Prevent running `v`'s destructor so we are in complete control
+ /// // of the allocation.
+ /// let mut v = mem::ManuallyDrop::new(v);
+ ///
+ /// // Pull out the various important pieces of information about `v`
+ /// let p = v.as_mut_ptr();
+ /// let len = v.len();
+ /// let cap = v.capacity();
+ ///
+ /// unsafe {
+ /// // Overwrite memory with 4, 5, 6
+ /// for i in 0..len as isize {
+ /// ptr::write(p.offset(i), 4 + i);
+ /// }
+ ///
+ /// // Put everything back together into a Vec
+ /// let rebuilt = Vec::from_raw_parts(p, len, cap);
+ /// assert_eq!(rebuilt, [4, 5, 6]);
+ /// }
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub unsafe fn from_raw_parts(ptr: *mut T, length: usize, capacity: usize) -> Self {
+ unsafe { Self::from_raw_parts_in(ptr, length, capacity, Global) }
+ }
+}
+
+impl<T, A: Allocator> Vec<T, A> {
+ /// Constructs a new, empty `Vec<T, A>`.
+ ///
+ /// The vector will not allocate until elements are pushed onto it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// # #[allow(unused_mut)]
+ /// let mut vec: Vec<i32, _> = Vec::new_in(System);
+ /// ```
+ #[inline]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ pub const fn new_in(alloc: A) -> Self {
+ Vec { buf: RawVec::new_in(alloc), len: 0 }
+ }
+
+ /// Constructs a new, empty `Vec<T, A>` with the specified capacity with the provided
+ /// allocator.
+ ///
+ /// The vector will be able to hold exactly `capacity` elements without
+ /// reallocating. If `capacity` is 0, the vector will not allocate.
+ ///
+ /// It is important to note that although the returned vector has the
+ /// *capacity* specified, the vector will have a zero *length*. For an
+ /// explanation of the difference between length and capacity, see
+ /// *[Capacity and reallocation]*.
+ ///
+ /// [Capacity and reallocation]: #capacity-and-reallocation
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let mut vec = Vec::with_capacity_in(10, System);
+ ///
+ /// // The vector contains no items, even though it has capacity for more
+ /// assert_eq!(vec.len(), 0);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // These are all done without reallocating...
+ /// for i in 0..10 {
+ /// vec.push(i);
+ /// }
+ /// assert_eq!(vec.len(), 10);
+ /// assert_eq!(vec.capacity(), 10);
+ ///
+ /// // ...but this may make the vector reallocate
+ /// vec.push(11);
+ /// assert_eq!(vec.len(), 11);
+ /// assert!(vec.capacity() >= 11);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
+ Vec { buf: RawVec::with_capacity_in(capacity, alloc), len: 0 }
+ }
+
+ /// Creates a `Vec<T, A>` directly from the raw components of another vector.
+ ///
+ /// # Safety
+ ///
+ /// This is highly unsafe, due to the number of invariants that aren't
+ /// checked:
+ ///
+ /// * `ptr` needs to have been previously allocated via [`String`]/`Vec<T>`
+ /// (at least, it's highly likely to be incorrect if it wasn't).
+ /// * `T` needs to have the same size and alignment as what `ptr` was allocated with.
+ /// (`T` having a less strict alignment is not sufficient, the alignment really
+ /// needs to be equal to satisfy the [`dealloc`] requirement that memory must be
+ /// allocated and deallocated with the same layout.)
+ /// * `length` needs to be less than or equal to `capacity`.
+ /// * `capacity` needs to be the capacity that the pointer was allocated with.
+ ///
+ /// Violating these may cause problems like corrupting the allocator's
+ /// internal data structures. For example it is **not** safe
+ /// to build a `Vec<u8>` from a pointer to a C `char` array with length `size_t`.
+ /// It's also not safe to build one from a `Vec<u16>` and its length, because
+ /// the allocator cares about the alignment, and these two types have different
+ /// alignments. The buffer was allocated with alignment 2 (for `u16`), but after
+ /// turning it into a `Vec<u8>` it'll be deallocated with alignment 1.
+ ///
+ /// The ownership of `ptr` is effectively transferred to the
+ /// `Vec<T>` which may then deallocate, reallocate or change the
+ /// contents of memory pointed to by the pointer at will. Ensure
+ /// that nothing else uses the pointer after calling this
+ /// function.
+ ///
+ /// [`String`]: crate::string::String
+ /// [`dealloc`]: crate::alloc::GlobalAlloc::dealloc
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// use std::ptr;
+ /// use std::mem;
+ ///
+ /// let mut v = Vec::with_capacity_in(3, System);
+ /// v.push(1);
+ /// v.push(2);
+ /// v.push(3);
+ ///
+ // FIXME Update this when vec_into_raw_parts is stabilized
+ /// // Prevent running `v`'s destructor so we are in complete control
+ /// // of the allocation.
+ /// let mut v = mem::ManuallyDrop::new(v);
+ ///
+ /// // Pull out the various important pieces of information about `v`
+ /// let p = v.as_mut_ptr();
+ /// let len = v.len();
+ /// let cap = v.capacity();
+ /// let alloc = v.allocator();
+ ///
+ /// unsafe {
+ /// // Overwrite memory with 4, 5, 6
+ /// for i in 0..len as isize {
+ /// ptr::write(p.offset(i), 4 + i);
+ /// }
+ ///
+ /// // Put everything back together into a Vec
+ /// let rebuilt = Vec::from_raw_parts_in(p, len, cap, alloc.clone());
+ /// assert_eq!(rebuilt, [4, 5, 6]);
+ /// }
+ /// ```
+ #[inline]
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ pub unsafe fn from_raw_parts_in(ptr: *mut T, length: usize, capacity: usize, alloc: A) -> Self {
+ unsafe { Vec { buf: RawVec::from_raw_parts_in(ptr, capacity, alloc), len: length } }
+ }
+
+ /// Decomposes a `Vec<T>` into its raw components.
+ ///
+ /// Returns the raw pointer to the underlying data, the length of
+ /// the vector (in elements), and the allocated capacity of the
+ /// data (in elements). These are the same arguments in the same
+ /// order as the arguments to [`from_raw_parts`].
+ ///
+ /// After calling this function, the caller is responsible for the
+ /// memory previously managed by the `Vec`. The only way to do
+ /// this is to convert the raw pointer, length, and capacity back
+ /// into a `Vec` with the [`from_raw_parts`] function, allowing
+ /// the destructor to perform the cleanup.
+ ///
+ /// [`from_raw_parts`]: Vec::from_raw_parts
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(vec_into_raw_parts)]
+ /// let v: Vec<i32> = vec![-1, 0, 1];
+ ///
+ /// let (ptr, len, cap) = v.into_raw_parts();
+ ///
+ /// let rebuilt = unsafe {
+ /// // We can now make changes to the components, such as
+ /// // transmuting the raw pointer to a compatible type.
+ /// let ptr = ptr as *mut u32;
+ ///
+ /// Vec::from_raw_parts(ptr, len, cap)
+ /// };
+ /// assert_eq!(rebuilt, [4294967295, 0, 1]);
+ /// ```
+ #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
+ pub fn into_raw_parts(self) -> (*mut T, usize, usize) {
+ let mut me = ManuallyDrop::new(self);
+ (me.as_mut_ptr(), me.len(), me.capacity())
+ }
+
+ /// Decomposes a `Vec<T>` into its raw components.
+ ///
+ /// Returns the raw pointer to the underlying data, the length of the vector (in elements),
+ /// the allocated capacity of the data (in elements), and the allocator. These are the same
+ /// arguments in the same order as the arguments to [`from_raw_parts_in`].
+ ///
+ /// After calling this function, the caller is responsible for the
+ /// memory previously managed by the `Vec`. The only way to do
+ /// this is to convert the raw pointer, length, and capacity back
+ /// into a `Vec` with the [`from_raw_parts_in`] function, allowing
+ /// the destructor to perform the cleanup.
+ ///
+ /// [`from_raw_parts_in`]: Vec::from_raw_parts_in
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(allocator_api, vec_into_raw_parts)]
+ ///
+ /// use std::alloc::System;
+ ///
+ /// let mut v: Vec<i32, System> = Vec::new_in(System);
+ /// v.push(-1);
+ /// v.push(0);
+ /// v.push(1);
+ ///
+ /// let (ptr, len, cap, alloc) = v.into_raw_parts_with_alloc();
+ ///
+ /// let rebuilt = unsafe {
+ /// // We can now make changes to the components, such as
+ /// // transmuting the raw pointer to a compatible type.
+ /// let ptr = ptr as *mut u32;
+ ///
+ /// Vec::from_raw_parts_in(ptr, len, cap, alloc)
+ /// };
+ /// assert_eq!(rebuilt, [4294967295, 0, 1]);
+ /// ```
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ // #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
+ pub fn into_raw_parts_with_alloc(self) -> (*mut T, usize, usize, A) {
+ let mut me = ManuallyDrop::new(self);
+ let len = me.len();
+ let capacity = me.capacity();
+ let ptr = me.as_mut_ptr();
+ let alloc = unsafe { ptr::read(me.allocator()) };
+ (ptr, len, capacity, alloc)
+ }
+
+ /// Returns the number of elements the vector can hold without
+ /// reallocating.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let vec: Vec<i32> = Vec::with_capacity(10);
+ /// assert_eq!(vec.capacity(), 10);
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn capacity(&self) -> usize {
+ self.buf.capacity()
+ }
+
+ /// Reserves capacity for at least `additional` more elements to be inserted
+ /// in the given `Vec<T>`. The collection may reserve more space to avoid
+ /// frequent reallocations. After calling `reserve`, capacity will be
+ /// greater than or equal to `self.len() + additional`. Does nothing if
+ /// capacity is already sufficient.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1];
+ /// vec.reserve(10);
+ /// assert!(vec.capacity() >= 11);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn reserve(&mut self, additional: usize) {
+ self.buf.reserve(self.len, additional);
+ }
+
+ /// Reserves the minimum capacity for exactly `additional` more elements to
+ /// be inserted in the given `Vec<T>`. After calling `reserve_exact`,
+ /// capacity will be greater than or equal to `self.len() + additional`.
+ /// Does nothing if the capacity is already sufficient.
+ ///
+ /// Note that the allocator may give the collection more space than it
+ /// requests. Therefore, capacity can not be relied upon to be precisely
+ /// minimal. Prefer [`reserve`] if future insertions are expected.
+ ///
+ /// [`reserve`]: Vec::reserve
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1];
+ /// vec.reserve_exact(10);
+ /// assert!(vec.capacity() >= 11);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn reserve_exact(&mut self, additional: usize) {
+ self.buf.reserve_exact(self.len, additional);
+ }
+
+ /// Tries to reserve capacity for at least `additional` more elements to be inserted
+ /// in the given `Vec<T>`. The collection may reserve more space to avoid
+ /// frequent reallocations. After calling `try_reserve`, capacity will be
+ /// greater than or equal to `self.len() + additional`. Does nothing if
+ /// capacity is already sufficient.
+ ///
+ /// # Errors
+ ///
+ /// If the capacity overflows, or the allocator reports a failure, then an error
+ /// is returned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::collections::TryReserveError;
+ ///
+ /// fn process_data(data: &[u32]) -> Result<Vec<u32>, TryReserveError> {
+ /// let mut output = Vec::new();
+ ///
+ /// // Pre-reserve the memory, exiting if we can't
+ /// output.try_reserve(data.len())?;
+ ///
+ /// // Now we know this can't OOM in the middle of our complex work
+ /// output.extend(data.iter().map(|&val| {
+ /// val * 2 + 5 // very complicated
+ /// }));
+ ///
+ /// Ok(output)
+ /// }
+ /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
+ /// ```
+ #[stable(feature = "try_reserve", since = "1.57.0")]
+ pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.buf.try_reserve(self.len, additional)
+ }
+
+ /// Tries to reserve the minimum capacity for exactly `additional`
+ /// elements to be inserted in the given `Vec<T>`. After calling
+ /// `try_reserve_exact`, capacity will be greater than or equal to
+ /// `self.len() + additional` if it returns `Ok(())`.
+ /// Does nothing if the capacity is already sufficient.
+ ///
+ /// Note that the allocator may give the collection more space than it
+ /// requests. Therefore, capacity can not be relied upon to be precisely
+ /// minimal. Prefer [`try_reserve`] if future insertions are expected.
+ ///
+ /// [`try_reserve`]: Vec::try_reserve
+ ///
+ /// # Errors
+ ///
+ /// If the capacity overflows, or the allocator reports a failure, then an error
+ /// is returned.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::collections::TryReserveError;
+ ///
+ /// fn process_data(data: &[u32]) -> Result<Vec<u32>, TryReserveError> {
+ /// let mut output = Vec::new();
+ ///
+ /// // Pre-reserve the memory, exiting if we can't
+ /// output.try_reserve_exact(data.len())?;
+ ///
+ /// // Now we know this can't OOM in the middle of our complex work
+ /// output.extend(data.iter().map(|&val| {
+ /// val * 2 + 5 // very complicated
+ /// }));
+ ///
+ /// Ok(output)
+ /// }
+ /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
+ /// ```
+ #[stable(feature = "try_reserve", since = "1.57.0")]
+ pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
+ self.buf.try_reserve_exact(self.len, additional)
+ }
+
+ /// Shrinks the capacity of the vector as much as possible.
+ ///
+ /// It will drop down as close as possible to the length but the allocator
+ /// may still inform the vector that there is space for a few more elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ /// vec.extend([1, 2, 3]);
+ /// assert_eq!(vec.capacity(), 10);
+ /// vec.shrink_to_fit();
+ /// assert!(vec.capacity() >= 3);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn shrink_to_fit(&mut self) {
+ // The capacity is never less than the length, and there's nothing to do when
+ // they are equal, so we can avoid the panic case in `RawVec::shrink_to_fit`
+ // by only calling it with a greater capacity.
+ if self.capacity() > self.len {
+ self.buf.shrink_to_fit(self.len);
+ }
+ }
+
+ /// Shrinks the capacity of the vector with a lower bound.
+ ///
+ /// The capacity will remain at least as large as both the length
+ /// and the supplied value.
+ ///
+ /// If the current capacity is less than the lower limit, this is a no-op.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ /// vec.extend([1, 2, 3]);
+ /// assert_eq!(vec.capacity(), 10);
+ /// vec.shrink_to(4);
+ /// assert!(vec.capacity() >= 4);
+ /// vec.shrink_to(0);
+ /// assert!(vec.capacity() >= 3);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "shrink_to", since = "1.56.0")]
+ pub fn shrink_to(&mut self, min_capacity: usize) {
+ if self.capacity() > min_capacity {
+ self.buf.shrink_to_fit(cmp::max(self.len, min_capacity));
+ }
+ }
+
+ /// Converts the vector into [`Box<[T]>`][owned slice].
+ ///
+ /// Note that this will drop any excess capacity.
+ ///
+ /// [owned slice]: Box
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let v = vec![1, 2, 3];
+ ///
+ /// let slice = v.into_boxed_slice();
+ /// ```
+ ///
+ /// Any excess capacity is removed:
+ ///
+ /// ```
+ /// let mut vec = Vec::with_capacity(10);
+ /// vec.extend([1, 2, 3]);
+ ///
+ /// assert_eq!(vec.capacity(), 10);
+ /// let slice = vec.into_boxed_slice();
+ /// assert_eq!(slice.into_vec().capacity(), 3);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn into_boxed_slice(mut self) -> Box<[T], A> {
+ unsafe {
+ self.shrink_to_fit();
+ let me = ManuallyDrop::new(self);
+ let buf = ptr::read(&me.buf);
+ let len = me.len();
+ buf.into_box(len).assume_init()
+ }
+ }
+
+ /// Shortens the vector, keeping the first `len` elements and dropping
+ /// the rest.
+ ///
+ /// If `len` is greater than the vector's current length, this has no
+ /// effect.
+ ///
+ /// The [`drain`] method can emulate `truncate`, but causes the excess
+ /// elements to be returned instead of dropped.
+ ///
+ /// Note that this method has no effect on the allocated capacity
+ /// of the vector.
+ ///
+ /// # Examples
+ ///
+ /// Truncating a five element vector to two elements:
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3, 4, 5];
+ /// vec.truncate(2);
+ /// assert_eq!(vec, [1, 2]);
+ /// ```
+ ///
+ /// No truncation occurs when `len` is greater than the vector's current
+ /// length:
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// vec.truncate(8);
+ /// assert_eq!(vec, [1, 2, 3]);
+ /// ```
+ ///
+ /// Truncating when `len == 0` is equivalent to calling the [`clear`]
+ /// method.
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// vec.truncate(0);
+ /// assert_eq!(vec, []);
+ /// ```
+ ///
+ /// [`clear`]: Vec::clear
+ /// [`drain`]: Vec::drain
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn truncate(&mut self, len: usize) {
+ // This is safe because:
+ //
+ // * the slice passed to `drop_in_place` is valid; the `len > self.len`
+ // case avoids creating an invalid slice, and
+ // * the `len` of the vector is shrunk before calling `drop_in_place`,
+ // such that no value will be dropped twice in case `drop_in_place`
+ // were to panic once (if it panics twice, the program aborts).
+ unsafe {
+ // Note: It's intentional that this is `>` and not `>=`.
+ // Changing it to `>=` has negative performance
+ // implications in some cases. See #78884 for more.
+ if len > self.len {
+ return;
+ }
+ let remaining_len = self.len - len;
+ let s = ptr::slice_from_raw_parts_mut(self.as_mut_ptr().add(len), remaining_len);
+ self.len = len;
+ ptr::drop_in_place(s);
+ }
+ }
+
+ /// Extracts a slice containing the entire vector.
+ ///
+ /// Equivalent to `&s[..]`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{self, Write};
+ /// let buffer = vec![1, 2, 3, 5, 8];
+ /// io::sink().write(buffer.as_slice()).unwrap();
+ /// ```
+ #[inline]
+ #[stable(feature = "vec_as_slice", since = "1.7.0")]
+ pub fn as_slice(&self) -> &[T] {
+ self
+ }
+
+ /// Extracts a mutable slice of the entire vector.
+ ///
+ /// Equivalent to `&mut s[..]`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::io::{self, Read};
+ /// let mut buffer = vec![0; 3];
+ /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();
+ /// ```
+ #[inline]
+ #[stable(feature = "vec_as_slice", since = "1.7.0")]
+ pub fn as_mut_slice(&mut self) -> &mut [T] {
+ self
+ }
+
+ /// Returns a raw pointer to the vector's buffer.
+ ///
+ /// The caller must ensure that the vector outlives the pointer this
+ /// function returns, or else it will end up pointing to garbage.
+ /// Modifying the vector may cause its buffer to be reallocated,
+ /// which would also make any pointers to it invalid.
+ ///
+ /// The caller must also ensure that the memory the pointer (non-transitively) points to
+ /// is never written to (except inside an `UnsafeCell`) using this pointer or any pointer
+ /// derived from it. If you need to mutate the contents of the slice, use [`as_mut_ptr`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let x = vec![1, 2, 4];
+ /// let x_ptr = x.as_ptr();
+ ///
+ /// unsafe {
+ /// for i in 0..x.len() {
+ /// assert_eq!(*x_ptr.add(i), 1 << i);
+ /// }
+ /// }
+ /// ```
+ ///
+ /// [`as_mut_ptr`]: Vec::as_mut_ptr
+ #[stable(feature = "vec_as_ptr", since = "1.37.0")]
+ #[inline]
+ pub fn as_ptr(&self) -> *const T {
+ // We shadow the slice method of the same name to avoid going through
+ // `deref`, which creates an intermediate reference.
+ let ptr = self.buf.ptr();
+ unsafe {
+ assume(!ptr.is_null());
+ }
+ ptr
+ }
+
+ /// Returns an unsafe mutable pointer to the vector's buffer.
+ ///
+ /// The caller must ensure that the vector outlives the pointer this
+ /// function returns, or else it will end up pointing to garbage.
+ /// Modifying the vector may cause its buffer to be reallocated,
+ /// which would also make any pointers to it invalid.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// // Allocate vector big enough for 4 elements.
+ /// let size = 4;
+ /// let mut x: Vec<i32> = Vec::with_capacity(size);
+ /// let x_ptr = x.as_mut_ptr();
+ ///
+ /// // Initialize elements via raw pointer writes, then set length.
+ /// unsafe {
+ /// for i in 0..size {
+ /// *x_ptr.add(i) = i as i32;
+ /// }
+ /// x.set_len(size);
+ /// }
+ /// assert_eq!(&*x, &[0, 1, 2, 3]);
+ /// ```
+ #[stable(feature = "vec_as_ptr", since = "1.37.0")]
+ #[inline]
+ pub fn as_mut_ptr(&mut self) -> *mut T {
+ // We shadow the slice method of the same name to avoid going through
+ // `deref_mut`, which creates an intermediate reference.
+ let ptr = self.buf.ptr();
+ unsafe {
+ assume(!ptr.is_null());
+ }
+ ptr
+ }
+
+ /// Returns a reference to the underlying allocator.
+ #[unstable(feature = "allocator_api", issue = "32838")]
+ #[inline]
+ pub fn allocator(&self) -> &A {
+ self.buf.allocator()
+ }
+
+ /// Forces the length of the vector to `new_len`.
+ ///
+ /// This is a low-level operation that maintains none of the normal
+ /// invariants of the type. Normally changing the length of a vector
+ /// is done using one of the safe operations instead, such as
+ /// [`truncate`], [`resize`], [`extend`], or [`clear`].
+ ///
+ /// [`truncate`]: Vec::truncate
+ /// [`resize`]: Vec::resize
+ /// [`extend`]: Extend::extend
+ /// [`clear`]: Vec::clear
+ ///
+ /// # Safety
+ ///
+ /// - `new_len` must be less than or equal to [`capacity()`].
+ /// - The elements at `old_len..new_len` must be initialized.
+ ///
+ /// [`capacity()`]: Vec::capacity
+ ///
+ /// # Examples
+ ///
+ /// This method can be useful for situations in which the vector
+ /// is serving as a buffer for other code, particularly over FFI:
+ ///
+ /// ```no_run
+ /// # #![allow(dead_code)]
+ /// # // This is just a minimal skeleton for the doc example;
+ /// # // don't use this as a starting point for a real library.
+ /// # pub struct StreamWrapper { strm: *mut std::ffi::c_void }
+ /// # const Z_OK: i32 = 0;
+ /// # extern "C" {
+ /// # fn deflateGetDictionary(
+ /// # strm: *mut std::ffi::c_void,
+ /// # dictionary: *mut u8,
+ /// # dictLength: *mut usize,
+ /// # ) -> i32;
+ /// # }
+ /// # impl StreamWrapper {
+ /// pub fn get_dictionary(&self) -> Option<Vec<u8>> {
+ /// // Per the FFI method's docs, "32768 bytes is always enough".
+ /// let mut dict = Vec::with_capacity(32_768);
+ /// let mut dict_length = 0;
+ /// // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that:
+ /// // 1. `dict_length` elements were initialized.
+ /// // 2. `dict_length` <= the capacity (32_768)
+ /// // which makes `set_len` safe to call.
+ /// unsafe {
+ /// // Make the FFI call...
+ /// let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length);
+ /// if r == Z_OK {
+ /// // ...and update the length to what was initialized.
+ /// dict.set_len(dict_length);
+ /// Some(dict)
+ /// } else {
+ /// None
+ /// }
+ /// }
+ /// }
+ /// # }
+ /// ```
+ ///
+ /// While the following example is sound, there is a memory leak since
+ /// the inner vectors were not freed prior to the `set_len` call:
+ ///
+ /// ```
+ /// let mut vec = vec![vec![1, 0, 0],
+ /// vec![0, 1, 0],
+ /// vec![0, 0, 1]];
+ /// // SAFETY:
+ /// // 1. `old_len..0` is empty so no elements need to be initialized.
+ /// // 2. `0 <= capacity` always holds whatever `capacity` is.
+ /// unsafe {
+ /// vec.set_len(0);
+ /// }
+ /// ```
+ ///
+ /// Normally, here, one would use [`clear`] instead to correctly drop
+ /// the contents and thus not leak memory.
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub unsafe fn set_len(&mut self, new_len: usize) {
+ debug_assert!(new_len <= self.capacity());
+
+ self.len = new_len;
+ }
+
+ /// Removes an element from the vector and returns it.
+ ///
+ /// The removed element is replaced by the last element of the vector.
+ ///
+ /// This does not preserve ordering, but is *O*(1).
+ /// If you need to preserve the element order, use [`remove`] instead.
+ ///
+ /// [`remove`]: Vec::remove
+ ///
+ /// # Panics
+ ///
+ /// Panics if `index` is out of bounds.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = vec!["foo", "bar", "baz", "qux"];
+ ///
+ /// assert_eq!(v.swap_remove(1), "bar");
+ /// assert_eq!(v, ["foo", "qux", "baz"]);
+ ///
+ /// assert_eq!(v.swap_remove(0), "foo");
+ /// assert_eq!(v, ["baz", "qux"]);
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn swap_remove(&mut self, index: usize) -> T {
+ #[cold]
+ #[inline(never)]
+ fn assert_failed(index: usize, len: usize) -> ! {
+ panic!("swap_remove index (is {}) should be < len (is {})", index, len);
+ }
+
+ let len = self.len();
+ if index >= len {
+ assert_failed(index, len);
+ }
+ unsafe {
+ // We replace self[index] with the last element. Note that if the
+ // bounds check above succeeds there must be a last element (which
+ // can be self[index] itself).
+ let value = ptr::read(self.as_ptr().add(index));
+ let base_ptr = self.as_mut_ptr();
+ ptr::copy(base_ptr.add(len - 1), base_ptr.add(index), 1);
+ self.set_len(len - 1);
+ value
+ }
+ }
+
+ /// Inserts an element at position `index` within the vector, shifting all
+ /// elements after it to the right.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `index > len`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// vec.insert(1, 4);
+ /// assert_eq!(vec, [1, 4, 2, 3]);
+ /// vec.insert(4, 5);
+ /// assert_eq!(vec, [1, 4, 2, 3, 5]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn insert(&mut self, index: usize, element: T) {
+ #[cold]
+ #[inline(never)]
+ fn assert_failed(index: usize, len: usize) -> ! {
+ panic!("insertion index (is {}) should be <= len (is {})", index, len);
+ }
+
+ let len = self.len();
+ if index > len {
+ assert_failed(index, len);
+ }
+
+ // space for the new element
+ if len == self.buf.capacity() {
+ self.reserve(1);
+ }
+
+ unsafe {
+ // infallible
+ // The spot to put the new value
+ {
+ let p = self.as_mut_ptr().add(index);
+ // Shift everything over to make space. (Duplicating the
+ // `index`th element into two consecutive places.)
+ ptr::copy(p, p.offset(1), len - index);
+ // Write it in, overwriting the first copy of the `index`th
+ // element.
+ ptr::write(p, element);
+ }
+ self.set_len(len + 1);
+ }
+ }
+
+ /// Removes and returns the element at position `index` within the vector,
+ /// shifting all elements after it to the left.
+ ///
+ /// Note: Because this shifts over the remaining elements, it has a
+ /// worst-case performance of *O*(*n*). If you don't need the order of elements
+ /// to be preserved, use [`swap_remove`] instead. If you'd like to remove
+ /// elements from the beginning of the `Vec`, consider using
+ /// [`VecDeque::pop_front`] instead.
+ ///
+ /// [`swap_remove`]: Vec::swap_remove
+ /// [`VecDeque::pop_front`]: crate::collections::VecDeque::pop_front
+ ///
+ /// # Panics
+ ///
+ /// Panics if `index` is out of bounds.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = vec![1, 2, 3];
+ /// assert_eq!(v.remove(1), 2);
+ /// assert_eq!(v, [1, 3]);
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[track_caller]
+ pub fn remove(&mut self, index: usize) -> T {
+ #[cold]
+ #[inline(never)]
+ #[track_caller]
+ fn assert_failed(index: usize, len: usize) -> ! {
+ panic!("removal index (is {}) should be < len (is {})", index, len);
+ }
+
+ let len = self.len();
+ if index >= len {
+ assert_failed(index, len);
+ }
+ unsafe {
+ // infallible
+ let ret;
+ {
+ // the place we are taking from.
+ let ptr = self.as_mut_ptr().add(index);
+ // copy it out, unsafely having a copy of the value on
+ // the stack and in the vector at the same time.
+ ret = ptr::read(ptr);
+
+ // Shift everything down to fill in that spot.
+ ptr::copy(ptr.offset(1), ptr, len - index - 1);
+ }
+ self.set_len(len - 1);
+ ret
+ }
+ }
+
+ /// Retains only the elements specified by the predicate.
+ ///
+ /// In other words, remove all elements `e` such that `f(&e)` returns `false`.
+ /// This method operates in place, visiting each element exactly once in the
+ /// original order, and preserves the order of the retained elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3, 4];
+ /// vec.retain(|&x| x % 2 == 0);
+ /// assert_eq!(vec, [2, 4]);
+ /// ```
+ ///
+ /// Because the elements are visited exactly once in the original order,
+ /// external state may be used to decide which elements to keep.
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3, 4, 5];
+ /// let keep = [false, true, true, false, true];
+ /// let mut iter = keep.iter();
+ /// vec.retain(|_| *iter.next().unwrap());
+ /// assert_eq!(vec, [2, 3, 5]);
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn retain<F>(&mut self, mut f: F)
+ where
+ F: FnMut(&T) -> bool,
+ {
+ self.retain_mut(|elem| f(elem));
+ }
+
+ /// Retains only the elements specified by the predicate, passing a mutable reference to it.
+ ///
+ /// In other words, remove all elements `e` such that `f(&mut e)` returns `false`.
+ /// This method operates in place, visiting each element exactly once in the
+ /// original order, and preserves the order of the retained elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(vec_retain_mut)]
+ ///
+ /// let mut vec = vec![1, 2, 3, 4];
+ /// vec.retain_mut(|x| if *x > 3 {
+ /// false
+ /// } else {
+ /// *x += 1;
+ /// true
+ /// });
+ /// assert_eq!(vec, [2, 3, 4]);
+ /// ```
+ #[unstable(feature = "vec_retain_mut", issue = "90829")]
+ pub fn retain_mut<F>(&mut self, mut f: F)
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ let original_len = self.len();
+ // Avoid double drop if the drop guard is not executed,
+ // since we may make some holes during the process.
+ unsafe { self.set_len(0) };
+
+ // Vec: [Kept, Kept, Hole, Hole, Hole, Hole, Unchecked, Unchecked]
+ // |<- processed len ->| ^- next to check
+ // |<- deleted cnt ->|
+ // |<- original_len ->|
+ // Kept: Elements which predicate returns true on.
+ // Hole: Moved or dropped element slot.
+ // Unchecked: Unchecked valid elements.
+ //
+ // This drop guard will be invoked when predicate or `drop` of element panicked.
+ // It shifts unchecked elements to cover holes and `set_len` to the correct length.
+ // In cases when predicate and `drop` never panick, it will be optimized out.
+ struct BackshiftOnDrop<'a, T, A: Allocator> {
+ v: &'a mut Vec<T, A>,
+ processed_len: usize,
+ deleted_cnt: usize,
+ original_len: usize,
+ }
+
+ impl<T, A: Allocator> Drop for BackshiftOnDrop<'_, T, A> {
+ fn drop(&mut self) {
+ if self.deleted_cnt > 0 {
+ // SAFETY: Trailing unchecked items must be valid since we never touch them.
+ unsafe {
+ ptr::copy(
+ self.v.as_ptr().add(self.processed_len),
+ self.v.as_mut_ptr().add(self.processed_len - self.deleted_cnt),
+ self.original_len - self.processed_len,
+ );
+ }
+ }
+ // SAFETY: After filling holes, all items are in contiguous memory.
+ unsafe {
+ self.v.set_len(self.original_len - self.deleted_cnt);
+ }
+ }
+ }
+
+ let mut g = BackshiftOnDrop { v: self, processed_len: 0, deleted_cnt: 0, original_len };
+
+ fn process_loop<F, T, A: Allocator, const DELETED: bool>(
+ original_len: usize,
+ f: &mut F,
+ g: &mut BackshiftOnDrop<'_, T, A>,
+ ) where
+ F: FnMut(&mut T) -> bool,
+ {
+ while g.processed_len != original_len {
+ // SAFETY: Unchecked element must be valid.
+ let cur = unsafe { &mut *g.v.as_mut_ptr().add(g.processed_len) };
+ if !f(cur) {
+ // Advance early to avoid double drop if `drop_in_place` panicked.
+ g.processed_len += 1;
+ g.deleted_cnt += 1;
+ // SAFETY: We never touch this element again after dropped.
+ unsafe { ptr::drop_in_place(cur) };
+ // We already advanced the counter.
+ if DELETED {
+ continue;
+ } else {
+ break;
+ }
+ }
+ if DELETED {
+ // SAFETY: `deleted_cnt` > 0, so the hole slot must not overlap with current element.
+ // We use copy for move, and never touch this element again.
+ unsafe {
+ let hole_slot = g.v.as_mut_ptr().add(g.processed_len - g.deleted_cnt);
+ ptr::copy_nonoverlapping(cur, hole_slot, 1);
+ }
+ }
+ g.processed_len += 1;
+ }
+ }
+
+ // Stage 1: Nothing was deleted.
+ process_loop::<F, T, A, false>(original_len, &mut f, &mut g);
+
+ // Stage 2: Some elements were deleted.
+ process_loop::<F, T, A, true>(original_len, &mut f, &mut g);
+
+ // All item are processed. This can be optimized to `set_len` by LLVM.
+ drop(g);
+ }
+
+ /// Removes all but the first of consecutive elements in the vector that resolve to the same
+ /// key.
+ ///
+ /// If the vector is sorted, this removes all duplicates.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![10, 20, 21, 30, 20];
+ ///
+ /// vec.dedup_by_key(|i| *i / 10);
+ ///
+ /// assert_eq!(vec, [10, 20, 30, 20]);
+ /// ```
+ #[stable(feature = "dedup_by", since = "1.16.0")]
+ #[inline]
+ pub fn dedup_by_key<F, K>(&mut self, mut key: F)
+ where
+ F: FnMut(&mut T) -> K,
+ K: PartialEq,
+ {
+ self.dedup_by(|a, b| key(a) == key(b))
+ }
+
+ /// Removes all but the first of consecutive elements in the vector satisfying a given equality
+ /// relation.
+ ///
+ /// The `same_bucket` function is passed references to two elements from the vector and
+ /// must determine if the elements compare equal. The elements are passed in opposite order
+ /// from their order in the slice, so if `same_bucket(a, b)` returns `true`, `a` is removed.
+ ///
+ /// If the vector is sorted, this removes all duplicates.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec!["foo", "bar", "Bar", "baz", "bar"];
+ ///
+ /// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));
+ ///
+ /// assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
+ /// ```
+ #[stable(feature = "dedup_by", since = "1.16.0")]
+ pub fn dedup_by<F>(&mut self, mut same_bucket: F)
+ where
+ F: FnMut(&mut T, &mut T) -> bool,
+ {
+ let len = self.len();
+ if len <= 1 {
+ return;
+ }
+
+ /* INVARIANT: vec.len() > read >= write > write-1 >= 0 */
+ struct FillGapOnDrop<'a, T, A: core::alloc::Allocator> {
+ /* Offset of the element we want to check if it is duplicate */
+ read: usize,
+
+ /* Offset of the place where we want to place the non-duplicate
+ * when we find it. */
+ write: usize,
+
+ /* The Vec that would need correction if `same_bucket` panicked */
+ vec: &'a mut Vec<T, A>,
+ }
+
+ impl<'a, T, A: core::alloc::Allocator> Drop for FillGapOnDrop<'a, T, A> {
+ fn drop(&mut self) {
+ /* This code gets executed when `same_bucket` panics */
+
+ /* SAFETY: invariant guarantees that `read - write`
+ * and `len - read` never overflow and that the copy is always
+ * in-bounds. */
+ unsafe {
+ let ptr = self.vec.as_mut_ptr();
+ let len = self.vec.len();
+
+ /* How many items were left when `same_bucket` panicked.
+ * Basically vec[read..].len() */
+ let items_left = len.wrapping_sub(self.read);
+
+ /* Pointer to first item in vec[write..write+items_left] slice */
+ let dropped_ptr = ptr.add(self.write);
+ /* Pointer to first item in vec[read..] slice */
+ let valid_ptr = ptr.add(self.read);
+
+ /* Copy `vec[read..]` to `vec[write..write+items_left]`.
+ * The slices can overlap, so `copy_nonoverlapping` cannot be used */
+ ptr::copy(valid_ptr, dropped_ptr, items_left);
+
+ /* How many items have been already dropped
+ * Basically vec[read..write].len() */
+ let dropped = self.read.wrapping_sub(self.write);
+
+ self.vec.set_len(len - dropped);
+ }
+ }
+ }
+
+ let mut gap = FillGapOnDrop { read: 1, write: 1, vec: self };
+ let ptr = gap.vec.as_mut_ptr();
+
+ /* Drop items while going through Vec, it should be more efficient than
+ * doing slice partition_dedup + truncate */
+
+ /* SAFETY: Because of the invariant, read_ptr, prev_ptr and write_ptr
+ * are always in-bounds and read_ptr never aliases prev_ptr */
+ unsafe {
+ while gap.read < len {
+ let read_ptr = ptr.add(gap.read);
+ let prev_ptr = ptr.add(gap.write.wrapping_sub(1));
+
+ if same_bucket(&mut *read_ptr, &mut *prev_ptr) {
+ // Increase `gap.read` now since the drop may panic.
+ gap.read += 1;
+ /* We have found duplicate, drop it in-place */
+ ptr::drop_in_place(read_ptr);
+ } else {
+ let write_ptr = ptr.add(gap.write);
+
+ /* Because `read_ptr` can be equal to `write_ptr`, we either
+ * have to use `copy` or conditional `copy_nonoverlapping`.
+ * Looks like the first option is faster. */
+ ptr::copy(read_ptr, write_ptr, 1);
+
+ /* We have filled that place, so go further */
+ gap.write += 1;
+ gap.read += 1;
+ }
+ }
+
+ /* Technically we could let `gap` clean up with its Drop, but
+ * when `same_bucket` is guaranteed to not panic, this bloats a little
+ * the codegen, so we just do it manually */
+ gap.vec.set_len(gap.write);
+ mem::forget(gap);
+ }
+ }
+
+ /// Appends an element to the back of a collection.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the new capacity exceeds `isize::MAX` bytes.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2];
+ /// vec.push(3);
+ /// assert_eq!(vec, [1, 2, 3]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn push(&mut self, value: T) {
+ // This will panic or abort if we would allocate > isize::MAX bytes
+ // or if the length increment would overflow for zero-sized types.
+ if self.len == self.buf.capacity() {
+ self.buf.reserve_for_push(self.len);
+ }
+ unsafe {
+ let end = self.as_mut_ptr().add(self.len);
+ ptr::write(end, value);
+ self.len += 1;
+ }
+ }
+
+ /// Removes the last element from a vector and returns it, or [`None`] if it
+ /// is empty.
+ ///
+ /// If you'd like to pop the first element, consider using
+ /// [`VecDeque::pop_front`] instead.
+ ///
+ /// [`VecDeque::pop_front`]: crate::collections::VecDeque::pop_front
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// assert_eq!(vec.pop(), Some(3));
+ /// assert_eq!(vec, [1, 2]);
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn pop(&mut self) -> Option<T> {
+ if self.len == 0 {
+ None
+ } else {
+ unsafe {
+ self.len -= 1;
+ Some(ptr::read(self.as_ptr().add(self.len())))
+ }
+ }
+ }
+
+ /// Moves all the elements of `other` into `Self`, leaving `other` empty.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the number of elements in the vector overflows a `usize`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// let mut vec2 = vec![4, 5, 6];
+ /// vec.append(&mut vec2);
+ /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
+ /// assert_eq!(vec2, []);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "append", since = "1.4.0")]
+ pub fn append(&mut self, other: &mut Self) {
+ unsafe {
+ self.append_elements(other.as_slice() as _);
+ other.set_len(0);
+ }
+ }
+
+ /// Appends elements to `Self` from other buffer.
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ unsafe fn append_elements(&mut self, other: *const [T]) {
+ let count = unsafe { (*other).len() };
+ self.reserve(count);
+ let len = self.len();
+ unsafe { ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count) };
+ self.len += count;
+ }
+
+ /// Removes the specified range from the vector in bulk, returning all
+ /// removed elements as an iterator. If the iterator is dropped before
+ /// being fully consumed, it drops the remaining removed elements.
+ ///
+ /// The returned iterator keeps a mutable borrow on the vector to optimize
+ /// its implementation.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point is greater than the end point or if
+ /// the end point is greater than the length of the vector.
+ ///
+ /// # Leaking
+ ///
+ /// If the returned iterator goes out of scope without being dropped (due to
+ /// [`mem::forget`], for example), the vector may have lost and leaked
+ /// elements arbitrarily, including elements outside the range.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = vec![1, 2, 3];
+ /// let u: Vec<_> = v.drain(1..).collect();
+ /// assert_eq!(v, &[1]);
+ /// assert_eq!(u, &[2, 3]);
+ ///
+ /// // A full range clears the vector, like `clear()` does
+ /// v.drain(..);
+ /// assert_eq!(v, &[]);
+ /// ```
+ #[stable(feature = "drain", since = "1.6.0")]
+ pub fn drain<R>(&mut self, range: R) -> Drain<'_, T, A>
+ where
+ R: RangeBounds<usize>,
+ {
+ // Memory safety
+ //
+ // When the Drain is first created, it shortens the length of
+ // the source vector to make sure no uninitialized or moved-from elements
+ // are accessible at all if the Drain's destructor never gets to run.
+ //
+ // Drain will ptr::read out the values to remove.
+ // When finished, remaining tail of the vec is copied back to cover
+ // the hole, and the vector length is restored to the new length.
+ //
+ let len = self.len();
+ let Range { start, end } = slice::range(range, ..len);
+
+ unsafe {
+ // set self.vec length's to start, to be safe in case Drain is leaked
+ self.set_len(start);
+ // Use the borrow in the IterMut to indicate borrowing behavior of the
+ // whole Drain iterator (like &mut T).
+ let range_slice = slice::from_raw_parts_mut(self.as_mut_ptr().add(start), end - start);
+ Drain {
+ tail_start: end,
+ tail_len: len - end,
+ iter: range_slice.iter(),
+ vec: NonNull::from(self),
+ }
+ }
+ }
+
+ /// Clears the vector, removing all values.
+ ///
+ /// Note that this method has no effect on the allocated capacity
+ /// of the vector.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = vec![1, 2, 3];
+ ///
+ /// v.clear();
+ ///
+ /// assert!(v.is_empty());
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn clear(&mut self) {
+ self.truncate(0)
+ }
+
+ /// Returns the number of elements in the vector, also referred to
+ /// as its 'length'.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let a = vec![1, 2, 3];
+ /// assert_eq!(a.len(), 3);
+ /// ```
+ #[inline]
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn len(&self) -> usize {
+ self.len
+ }
+
+ /// Returns `true` if the vector contains no elements.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = Vec::new();
+ /// assert!(v.is_empty());
+ ///
+ /// v.push(1);
+ /// assert!(!v.is_empty());
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ pub fn is_empty(&self) -> bool {
+ self.len() == 0
+ }
+
+ /// Splits the collection into two at the given index.
+ ///
+ /// Returns a newly allocated vector containing the elements in the range
+ /// `[at, len)`. After the call, the original vector will be left containing
+ /// the elements `[0, at)` with its previous capacity unchanged.
+ ///
+ /// # Panics
+ ///
+ /// Panics if `at > len`.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// let vec2 = vec.split_off(1);
+ /// assert_eq!(vec, [1]);
+ /// assert_eq!(vec2, [2, 3]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[must_use = "use `.truncate()` if you don't need the other half"]
+ #[stable(feature = "split_off", since = "1.4.0")]
+ pub fn split_off(&mut self, at: usize) -> Self
+ where
+ A: Clone,
+ {
+ #[cold]
+ #[inline(never)]
+ fn assert_failed(at: usize, len: usize) -> ! {
+ panic!("`at` split index (is {}) should be <= len (is {})", at, len);
+ }
+
+ if at > self.len() {
+ assert_failed(at, self.len());
+ }
+
+ if at == 0 {
+ // the new vector can take over the original buffer and avoid the copy
+ return mem::replace(
+ self,
+ Vec::with_capacity_in(self.capacity(), self.allocator().clone()),
+ );
+ }
+
+ let other_len = self.len - at;
+ let mut other = Vec::with_capacity_in(other_len, self.allocator().clone());
+
+ // Unsafely `set_len` and copy items to `other`.
+ unsafe {
+ self.set_len(at);
+ other.set_len(other_len);
+
+ ptr::copy_nonoverlapping(self.as_ptr().add(at), other.as_mut_ptr(), other.len());
+ }
+ other
+ }
+
+ /// Resizes the `Vec` in-place so that `len` is equal to `new_len`.
+ ///
+ /// If `new_len` is greater than `len`, the `Vec` is extended by the
+ /// difference, with each additional slot filled with the result of
+ /// calling the closure `f`. The return values from `f` will end up
+ /// in the `Vec` in the order they have been generated.
+ ///
+ /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+ ///
+ /// This method uses a closure to create new values on every push. If
+ /// you'd rather [`Clone`] a given value, use [`Vec::resize`]. If you
+ /// want to use the [`Default`] trait to generate values, you can
+ /// pass [`Default::default`] as the second argument.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 3];
+ /// vec.resize_with(5, Default::default);
+ /// assert_eq!(vec, [1, 2, 3, 0, 0]);
+ ///
+ /// let mut vec = vec![];
+ /// let mut p = 1;
+ /// vec.resize_with(4, || { p *= 2; p });
+ /// assert_eq!(vec, [2, 4, 8, 16]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "vec_resize_with", since = "1.33.0")]
+ pub fn resize_with<F>(&mut self, new_len: usize, f: F)
+ where
+ F: FnMut() -> T,
+ {
+ let len = self.len();
+ if new_len > len {
+ self.extend_with(new_len - len, ExtendFunc(f));
+ } else {
+ self.truncate(new_len);
+ }
+ }
+
+ /// Consumes and leaks the `Vec`, returning a mutable reference to the contents,
+ /// `&'a mut [T]`. Note that the type `T` must outlive the chosen lifetime
+ /// `'a`. If the type has only static references, or none at all, then this
+ /// may be chosen to be `'static`.
+ ///
+ /// As of Rust 1.57, this method does not reallocate or shrink the `Vec`,
+ /// so the leaked allocation may include unused capacity that is not part
+ /// of the returned slice.
+ ///
+ /// This function is mainly useful for data that lives for the remainder of
+ /// the program's life. Dropping the returned reference will cause a memory
+ /// leak.
+ ///
+ /// # Examples
+ ///
+ /// Simple usage:
+ ///
+ /// ```
+ /// let x = vec![1, 2, 3];
+ /// let static_ref: &'static mut [usize] = x.leak();
+ /// static_ref[0] += 1;
+ /// assert_eq!(static_ref, &[2, 2, 3]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "vec_leak", since = "1.47.0")]
+ #[inline]
+ pub fn leak<'a>(self) -> &'a mut [T]
+ where
+ A: 'a,
+ {
+ let mut me = ManuallyDrop::new(self);
+ unsafe { slice::from_raw_parts_mut(me.as_mut_ptr(), me.len) }
+ }
+
+ /// Returns the remaining spare capacity of the vector as a slice of
+ /// `MaybeUninit<T>`.
+ ///
+ /// The returned slice can be used to fill the vector with data (e.g. by
+ /// reading from a file) before marking the data as initialized using the
+ /// [`set_len`] method.
+ ///
+ /// [`set_len`]: Vec::set_len
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// // Allocate vector big enough for 10 elements.
+ /// let mut v = Vec::with_capacity(10);
+ ///
+ /// // Fill in the first 3 elements.
+ /// let uninit = v.spare_capacity_mut();
+ /// uninit[0].write(0);
+ /// uninit[1].write(1);
+ /// uninit[2].write(2);
+ ///
+ /// // Mark the first 3 elements of the vector as being initialized.
+ /// unsafe {
+ /// v.set_len(3);
+ /// }
+ ///
+ /// assert_eq!(&v, &[0, 1, 2]);
+ /// ```
+ #[stable(feature = "vec_spare_capacity", since = "1.60.0")]
+ #[inline]
+ pub fn spare_capacity_mut(&mut self) -> &mut [MaybeUninit<T>] {
+ // Note:
+ // This method is not implemented in terms of `split_at_spare_mut`,
+ // to prevent invalidation of pointers to the buffer.
+ unsafe {
+ slice::from_raw_parts_mut(
+ self.as_mut_ptr().add(self.len) as *mut MaybeUninit<T>,
+ self.buf.capacity() - self.len,
+ )
+ }
+ }
+
+ /// Returns vector content as a slice of `T`, along with the remaining spare
+ /// capacity of the vector as a slice of `MaybeUninit<T>`.
+ ///
+ /// The returned spare capacity slice can be used to fill the vector with data
+ /// (e.g. by reading from a file) before marking the data as initialized using
+ /// the [`set_len`] method.
+ ///
+ /// [`set_len`]: Vec::set_len
+ ///
+ /// Note that this is a low-level API, which should be used with care for
+ /// optimization purposes. If you need to append data to a `Vec`
+ /// you can use [`push`], [`extend`], [`extend_from_slice`],
+ /// [`extend_from_within`], [`insert`], [`append`], [`resize`] or
+ /// [`resize_with`], depending on your exact needs.
+ ///
+ /// [`push`]: Vec::push
+ /// [`extend`]: Vec::extend
+ /// [`extend_from_slice`]: Vec::extend_from_slice
+ /// [`extend_from_within`]: Vec::extend_from_within
+ /// [`insert`]: Vec::insert
+ /// [`append`]: Vec::append
+ /// [`resize`]: Vec::resize
+ /// [`resize_with`]: Vec::resize_with
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// #![feature(vec_split_at_spare)]
+ ///
+ /// let mut v = vec![1, 1, 2];
+ ///
+ /// // Reserve additional space big enough for 10 elements.
+ /// v.reserve(10);
+ ///
+ /// let (init, uninit) = v.split_at_spare_mut();
+ /// let sum = init.iter().copied().sum::<u32>();
+ ///
+ /// // Fill in the next 4 elements.
+ /// uninit[0].write(sum);
+ /// uninit[1].write(sum * 2);
+ /// uninit[2].write(sum * 3);
+ /// uninit[3].write(sum * 4);
+ ///
+ /// // Mark the 4 elements of the vector as being initialized.
+ /// unsafe {
+ /// let len = v.len();
+ /// v.set_len(len + 4);
+ /// }
+ ///
+ /// assert_eq!(&v, &[1, 1, 2, 4, 8, 12, 16]);
+ /// ```
+ #[unstable(feature = "vec_split_at_spare", issue = "81944")]
+ #[inline]
+ pub fn split_at_spare_mut(&mut self) -> (&mut [T], &mut [MaybeUninit<T>]) {
+ // SAFETY:
+ // - len is ignored and so never changed
+ let (init, spare, _) = unsafe { self.split_at_spare_mut_with_len() };
+ (init, spare)
+ }
+
+ /// Safety: changing returned .2 (&mut usize) is considered the same as calling `.set_len(_)`.
+ ///
+ /// This method provides unique access to all vec parts at once in `extend_from_within`.
+ unsafe fn split_at_spare_mut_with_len(
+ &mut self,
+ ) -> (&mut [T], &mut [MaybeUninit<T>], &mut usize) {
+ let ptr = self.as_mut_ptr();
+ // SAFETY:
+ // - `ptr` is guaranteed to be valid for `self.len` elements
+ // - but the allocation extends out to `self.buf.capacity()` elements, possibly
+ // uninitialized
+ let spare_ptr = unsafe { ptr.add(self.len) };
+ let spare_ptr = spare_ptr.cast::<MaybeUninit<T>>();
+ let spare_len = self.buf.capacity() - self.len;
+
+ // SAFETY:
+ // - `ptr` is guaranteed to be valid for `self.len` elements
+ // - `spare_ptr` is pointing one element past the buffer, so it doesn't overlap with `initialized`
+ unsafe {
+ let initialized = slice::from_raw_parts_mut(ptr, self.len);
+ let spare = slice::from_raw_parts_mut(spare_ptr, spare_len);
+
+ (initialized, spare, &mut self.len)
+ }
+ }
+}
+
+impl<T: Clone, A: Allocator> Vec<T, A> {
+ /// Resizes the `Vec` in-place so that `len` is equal to `new_len`.
+ ///
+ /// If `new_len` is greater than `len`, the `Vec` is extended by the
+ /// difference, with each additional slot filled with `value`.
+ /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+ ///
+ /// This method requires `T` to implement [`Clone`],
+ /// in order to be able to clone the passed value.
+ /// If you need more flexibility (or want to rely on [`Default`] instead of
+ /// [`Clone`]), use [`Vec::resize_with`].
+ /// If you only need to resize to a smaller size, use [`Vec::truncate`].
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec!["hello"];
+ /// vec.resize(3, "world");
+ /// assert_eq!(vec, ["hello", "world", "world"]);
+ ///
+ /// let mut vec = vec![1, 2, 3, 4];
+ /// vec.resize(2, 0);
+ /// assert_eq!(vec, [1, 2]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "vec_resize", since = "1.5.0")]
+ pub fn resize(&mut self, new_len: usize, value: T) {
+ let len = self.len();
+
+ if new_len > len {
+ self.extend_with(new_len - len, ExtendElement(value))
+ } else {
+ self.truncate(new_len);
+ }
+ }
+
+ /// Clones and appends all elements in a slice to the `Vec`.
+ ///
+ /// Iterates over the slice `other`, clones each element, and then appends
+ /// it to this `Vec`. The `other` slice is traversed in-order.
+ ///
+ /// Note that this function is same as [`extend`] except that it is
+ /// specialized to work with slices instead. If and when Rust gets
+ /// specialization this function will likely be deprecated (but still
+ /// available).
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1];
+ /// vec.extend_from_slice(&[2, 3, 4]);
+ /// assert_eq!(vec, [1, 2, 3, 4]);
+ /// ```
+ ///
+ /// [`extend`]: Vec::extend
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "vec_extend_from_slice", since = "1.6.0")]
+ pub fn extend_from_slice(&mut self, other: &[T]) {
+ self.spec_extend(other.iter())
+ }
+
+ /// Copies elements from `src` range to the end of the vector.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point is greater than the end point or if
+ /// the end point is greater than the length of the vector.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![0, 1, 2, 3, 4];
+ ///
+ /// vec.extend_from_within(2..);
+ /// assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4]);
+ ///
+ /// vec.extend_from_within(..2);
+ /// assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4, 0, 1]);
+ ///
+ /// vec.extend_from_within(4..8);
+ /// assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4, 0, 1, 4, 2, 3, 4]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[stable(feature = "vec_extend_from_within", since = "1.53.0")]
+ pub fn extend_from_within<R>(&mut self, src: R)
+ where
+ R: RangeBounds<usize>,
+ {
+ let range = slice::range(src, ..self.len());
+ self.reserve(range.len());
+
+ // SAFETY:
+ // - `slice::range` guarantees that the given range is valid for indexing self
+ unsafe {
+ self.spec_extend_from_within(range);
+ }
+ }
+}
+
+// This code generalizes `extend_with_{element,default}`.
+trait ExtendWith<T> {
+ fn next(&mut self) -> T;
+ fn last(self) -> T;
+}
+
+struct ExtendElement<T>(T);
+impl<T: Clone> ExtendWith<T> for ExtendElement<T> {
+ fn next(&mut self) -> T {
+ self.0.clone()
+ }
+ fn last(self) -> T {
+ self.0
+ }
+}
+
+struct ExtendFunc<F>(F);
+impl<T, F: FnMut() -> T> ExtendWith<T> for ExtendFunc<F> {
+ fn next(&mut self) -> T {
+ (self.0)()
+ }
+ fn last(mut self) -> T {
+ (self.0)()
+ }
+}
+
+impl<T, A: Allocator> Vec<T, A> {
+ #[cfg(not(no_global_oom_handling))]
+ /// Extend the vector by `n` values, using the given generator.
+ fn extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) {
+ self.reserve(n);
+
+ unsafe {
+ let mut ptr = self.as_mut_ptr().add(self.len());
+ // Use SetLenOnDrop to work around bug where compiler
+ // might not realize the store through `ptr` through self.set_len()
+ // don't alias.
+ let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+ // Write all elements except the last one
+ for _ in 1..n {
+ ptr::write(ptr, value.next());
+ ptr = ptr.offset(1);
+ // Increment the length in every step in case next() panics
+ local_len.increment_len(1);
+ }
+
+ if n > 0 {
+ // We can write the last element directly without cloning needlessly
+ ptr::write(ptr, value.last());
+ local_len.increment_len(1);
+ }
+
+ // len set by scope guard
+ }
+ }
+}
+
+impl<T: PartialEq, A: Allocator> Vec<T, A> {
+ /// Removes consecutive repeated elements in the vector according to the
+ /// [`PartialEq`] trait implementation.
+ ///
+ /// If the vector is sorted, this removes all duplicates.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut vec = vec![1, 2, 2, 3, 2];
+ ///
+ /// vec.dedup();
+ ///
+ /// assert_eq!(vec, [1, 2, 3, 2]);
+ /// ```
+ #[stable(feature = "rust1", since = "1.0.0")]
+ #[inline]
+ pub fn dedup(&mut self) {
+ self.dedup_by(|a, b| a == b)
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Internal methods and functions
+////////////////////////////////////////////////////////////////////////////////
+
+#[doc(hidden)]
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn from_elem<T: Clone>(elem: T, n: usize) -> Vec<T> {
+ <T as SpecFromElem>::from_elem(elem, n, Global)
+}
+
+#[doc(hidden)]
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "allocator_api", issue = "32838")]
+pub fn from_elem_in<T: Clone, A: Allocator>(elem: T, n: usize, alloc: A) -> Vec<T, A> {
+ <T as SpecFromElem>::from_elem(elem, n, alloc)
+}
+
+trait ExtendFromWithinSpec {
+ /// # Safety
+ ///
+ /// - `src` needs to be valid index
+ /// - `self.capacity() - self.len()` must be `>= src.len()`
+ unsafe fn spec_extend_from_within(&mut self, src: Range<usize>);
+}
+
+impl<T: Clone, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
+ default unsafe fn spec_extend_from_within(&mut self, src: Range<usize>) {
+ // SAFETY:
+ // - len is increased only after initializing elements
+ let (this, spare, len) = unsafe { self.split_at_spare_mut_with_len() };
+
+ // SAFETY:
+ // - caller guaratees that src is a valid index
+ let to_clone = unsafe { this.get_unchecked(src) };
+
+ iter::zip(to_clone, spare)
+ .map(|(src, dst)| dst.write(src.clone()))
+ // Note:
+ // - Element was just initialized with `MaybeUninit::write`, so it's ok to increase len
+ // - len is increased after each element to prevent leaks (see issue #82533)
+ .for_each(|_| *len += 1);
+ }
+}
+
+impl<T: Copy, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
+ unsafe fn spec_extend_from_within(&mut self, src: Range<usize>) {
+ let count = src.len();
+ {
+ let (init, spare) = self.split_at_spare_mut();
+
+ // SAFETY:
+ // - caller guaratees that `src` is a valid index
+ let source = unsafe { init.get_unchecked(src) };
+
+ // SAFETY:
+ // - Both pointers are created from unique slice references (`&mut [_]`)
+ // so they are valid and do not overlap.
+ // - Elements are :Copy so it's OK to to copy them, without doing
+ // anything with the original values
+ // - `count` is equal to the len of `source`, so source is valid for
+ // `count` reads
+ // - `.reserve(count)` guarantees that `spare.len() >= count` so spare
+ // is valid for `count` writes
+ unsafe { ptr::copy_nonoverlapping(source.as_ptr(), spare.as_mut_ptr() as _, count) };
+ }
+
+ // SAFETY:
+ // - The elements were just initialized by `copy_nonoverlapping`
+ self.len += count;
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Common trait implementations for Vec
+////////////////////////////////////////////////////////////////////////////////
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> ops::Deref for Vec<T, A> {
+ type Target = [T];
+
+ fn deref(&self) -> &[T] {
+ unsafe { slice::from_raw_parts(self.as_ptr(), self.len) }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> ops::DerefMut for Vec<T, A> {
+ fn deref_mut(&mut self) -> &mut [T] {
+ unsafe { slice::from_raw_parts_mut(self.as_mut_ptr(), self.len) }
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+trait SpecCloneFrom {
+ fn clone_from(this: &mut Self, other: &Self);
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Clone, A: Allocator> SpecCloneFrom for Vec<T, A> {
+ default fn clone_from(this: &mut Self, other: &Self) {
+ // drop anything that will not be overwritten
+ this.truncate(other.len());
+
+ // self.len <= other.len due to the truncate above, so the
+ // slices here are always in-bounds.
+ let (init, tail) = other.split_at(this.len());
+
+ // reuse the contained values' allocations/resources.
+ this.clone_from_slice(init);
+ this.extend_from_slice(tail);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Copy, A: Allocator> SpecCloneFrom for Vec<T, A> {
+ fn clone_from(this: &mut Self, other: &Self) {
+ this.clear();
+ this.extend_from_slice(other);
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for Vec<T, A> {
+ #[cfg(not(test))]
+ fn clone(&self) -> Self {
+ let alloc = self.allocator().clone();
+ <[T]>::to_vec_in(&**self, alloc)
+ }
+
+ // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
+ // required for this method definition, is not available. Instead use the
+ // `slice::to_vec` function which is only available with cfg(test)
+ // NB see the slice::hack module in slice.rs for more information
+ #[cfg(test)]
+ fn clone(&self) -> Self {
+ let alloc = self.allocator().clone();
+ crate::slice::to_vec(&**self, alloc)
+ }
+
+ fn clone_from(&mut self, other: &Self) {
+ SpecCloneFrom::clone_from(self, other)
+ }
+}
+
+/// The hash of a vector is the same as that of the corresponding slice,
+/// as required by the `core::borrow::Borrow` implementation.
+///
+/// ```
+/// #![feature(build_hasher_simple_hash_one)]
+/// use std::hash::BuildHasher;
+///
+/// let b = std::collections::hash_map::RandomState::new();
+/// let v: Vec<u8> = vec![0xa8, 0x3c, 0x09];
+/// let s: &[u8] = &[0xa8, 0x3c, 0x09];
+/// assert_eq!(b.hash_one(v), b.hash_one(s));
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Hash, A: Allocator> Hash for Vec<T, A> {
+ #[inline]
+ fn hash<H: Hasher>(&self, state: &mut H) {
+ Hash::hash(&**self, state)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented(
+ message = "vector indices are of type `usize` or ranges of `usize`",
+ label = "vector indices are of type `usize` or ranges of `usize`"
+)]
+impl<T, I: SliceIndex<[T]>, A: Allocator> Index<I> for Vec<T, A> {
+ type Output = I::Output;
+
+ #[inline]
+ fn index(&self, index: I) -> &Self::Output {
+ Index::index(&**self, index)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented(
+ message = "vector indices are of type `usize` or ranges of `usize`",
+ label = "vector indices are of type `usize` or ranges of `usize`"
+)]
+impl<T, I: SliceIndex<[T]>, A: Allocator> IndexMut<I> for Vec<T, A> {
+ #[inline]
+ fn index_mut(&mut self, index: I) -> &mut Self::Output {
+ IndexMut::index_mut(&mut **self, index)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> FromIterator<T> for Vec<T> {
+ #[inline]
+ fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Vec<T> {
+ <Self as SpecFromIter<T, I::IntoIter>>::from_iter(iter.into_iter())
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> IntoIterator for Vec<T, A> {
+ type Item = T;
+ type IntoIter = IntoIter<T, A>;
+
+ /// Creates a consuming iterator, that is, one that moves each value out of
+ /// the vector (from start to end). The vector cannot be used after calling
+ /// this.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let v = vec!["a".to_string(), "b".to_string()];
+ /// for s in v.into_iter() {
+ /// // s has type String, not &String
+ /// println!("{}", s);
+ /// }
+ /// ```
+ #[inline]
+ fn into_iter(self) -> IntoIter<T, A> {
+ unsafe {
+ let mut me = ManuallyDrop::new(self);
+ let alloc = ptr::read(me.allocator());
+ let begin = me.as_mut_ptr();
+ let end = if mem::size_of::<T>() == 0 {
+ arith_offset(begin as *const i8, me.len() as isize) as *const T
+ } else {
+ begin.add(me.len()) as *const T
+ };
+ let cap = me.buf.capacity();
+ IntoIter {
+ buf: NonNull::new_unchecked(begin),
+ phantom: PhantomData,
+ cap,
+ alloc,
+ ptr: begin,
+ end,
+ }
+ }
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, A: Allocator> IntoIterator for &'a Vec<T, A> {
+ type Item = &'a T;
+ type IntoIter = slice::Iter<'a, T>;
+
+ fn into_iter(self) -> slice::Iter<'a, T> {
+ self.iter()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, A: Allocator> IntoIterator for &'a mut Vec<T, A> {
+ type Item = &'a mut T;
+ type IntoIter = slice::IterMut<'a, T>;
+
+ fn into_iter(self) -> slice::IterMut<'a, T> {
+ self.iter_mut()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> Extend<T> for Vec<T, A> {
+ #[inline]
+ fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
+ <Self as SpecExtend<T, I::IntoIter>>::spec_extend(self, iter.into_iter())
+ }
+
+ #[inline]
+ fn extend_one(&mut self, item: T) {
+ self.push(item);
+ }
+
+ #[inline]
+ fn extend_reserve(&mut self, additional: usize) {
+ self.reserve(additional);
+ }
+}
+
+impl<T, A: Allocator> Vec<T, A> {
+ // leaf method to which various SpecFrom/SpecExtend implementations delegate when
+ // they have no further optimizations to apply
+ #[cfg(not(no_global_oom_handling))]
+ fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) {
+ // This is the case for a general iterator.
+ //
+ // This function should be the moral equivalent of:
+ //
+ // for item in iterator {
+ // self.push(item);
+ // }
+ while let Some(element) = iterator.next() {
+ let len = self.len();
+ if len == self.capacity() {
+ let (lower, _) = iterator.size_hint();
+ self.reserve(lower.saturating_add(1));
+ }
+ unsafe {
+ ptr::write(self.as_mut_ptr().add(len), element);
+ // Since next() executes user code which can panic we have to bump the length
+ // after each step.
+ // NB can't overflow since we would have had to alloc the address space
+ self.set_len(len + 1);
+ }
+ }
+ }
+
+ /// Creates a splicing iterator that replaces the specified range in the vector
+ /// with the given `replace_with` iterator and yields the removed items.
+ /// `replace_with` does not need to be the same length as `range`.
+ ///
+ /// `range` is removed even if the iterator is not consumed until the end.
+ ///
+ /// It is unspecified how many elements are removed from the vector
+ /// if the `Splice` value is leaked.
+ ///
+ /// The input iterator `replace_with` is only consumed when the `Splice` value is dropped.
+ ///
+ /// This is optimal if:
+ ///
+ /// * The tail (elements in the vector after `range`) is empty,
+ /// * or `replace_with` yields fewer or equal elements than `range`’s length
+ /// * or the lower bound of its `size_hint()` is exact.
+ ///
+ /// Otherwise, a temporary vector is allocated and the tail is moved twice.
+ ///
+ /// # Panics
+ ///
+ /// Panics if the starting point is greater than the end point or if
+ /// the end point is greater than the length of the vector.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let mut v = vec![1, 2, 3, 4];
+ /// let new = [7, 8, 9];
+ /// let u: Vec<_> = v.splice(1..3, new).collect();
+ /// assert_eq!(v, &[1, 7, 8, 9, 4]);
+ /// assert_eq!(u, &[2, 3]);
+ /// ```
+ #[cfg(not(no_global_oom_handling))]
+ #[inline]
+ #[stable(feature = "vec_splice", since = "1.21.0")]
+ pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<'_, I::IntoIter, A>
+ where
+ R: RangeBounds<usize>,
+ I: IntoIterator<Item = T>,
+ {
+ Splice { drain: self.drain(range), replace_with: replace_with.into_iter() }
+ }
+
+ /// Creates an iterator which uses a closure to determine if an element should be removed.
+ ///
+ /// If the closure returns true, then the element is removed and yielded.
+ /// If the closure returns false, the element will remain in the vector and will not be yielded
+ /// by the iterator.
+ ///
+ /// Using this method is equivalent to the following code:
+ ///
+ /// ```
+ /// # let some_predicate = |x: &mut i32| { *x == 2 || *x == 3 || *x == 6 };
+ /// # let mut vec = vec![1, 2, 3, 4, 5, 6];
+ /// let mut i = 0;
+ /// while i < vec.len() {
+ /// if some_predicate(&mut vec[i]) {
+ /// let val = vec.remove(i);
+ /// // your code here
+ /// } else {
+ /// i += 1;
+ /// }
+ /// }
+ ///
+ /// # assert_eq!(vec, vec![1, 4, 5]);
+ /// ```
+ ///
+ /// But `drain_filter` is easier to use. `drain_filter` is also more efficient,
+ /// because it can backshift the elements of the array in bulk.
+ ///
+ /// Note that `drain_filter` also lets you mutate every element in the filter closure,
+ /// regardless of whether you choose to keep or remove it.
+ ///
+ /// # Examples
+ ///
+ /// Splitting an array into evens and odds, reusing the original allocation:
+ ///
+ /// ```
+ /// #![feature(drain_filter)]
+ /// let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15];
+ ///
+ /// let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+ /// let odds = numbers;
+ ///
+ /// assert_eq!(evens, vec![2, 4, 6, 8, 14]);
+ /// assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]);
+ /// ```
+ #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+ pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<'_, T, F, A>
+ where
+ F: FnMut(&mut T) -> bool,
+ {
+ let old_len = self.len();
+
+ // Guard against us getting leaked (leak amplification)
+ unsafe {
+ self.set_len(0);
+ }
+
+ DrainFilter { vec: self, idx: 0, del: 0, old_len, pred: filter, panic_flag: false }
+ }
+}
+
+/// Extend implementation that copies elements out of references before pushing them onto the Vec.
+///
+/// This implementation is specialized for slice iterators, where it uses [`copy_from_slice`] to
+/// append the entire slice at once.
+///
+/// [`copy_from_slice`]: slice::copy_from_slice
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_ref", since = "1.2.0")]
+impl<'a, T: Copy + 'a, A: Allocator + 'a> Extend<&'a T> for Vec<T, A> {
+ fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
+ self.spec_extend(iter.into_iter())
+ }
+
+ #[inline]
+ fn extend_one(&mut self, &item: &'a T) {
+ self.push(item);
+ }
+
+ #[inline]
+ fn extend_reserve(&mut self, additional: usize) {
+ self.reserve(additional);
+ }
+}
+
+/// Implements comparison of vectors, [lexicographically](core::cmp::Ord#lexicographical-comparison).
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: PartialOrd, A: Allocator> PartialOrd for Vec<T, A> {
+ #[inline]
+ fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+ PartialOrd::partial_cmp(&**self, &**other)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Eq, A: Allocator> Eq for Vec<T, A> {}
+
+/// Implements ordering of vectors, [lexicographically](core::cmp::Ord#lexicographical-comparison).
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Ord, A: Allocator> Ord for Vec<T, A> {
+ #[inline]
+ fn cmp(&self, other: &Self) -> Ordering {
+ Ord::cmp(&**self, &**other)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> {
+ fn drop(&mut self) {
+ unsafe {
+ // use drop for [T]
+ // use a raw slice to refer to the elements of the vector as weakest necessary type;
+ // could avoid questions of validity in certain cases
+ ptr::drop_in_place(ptr::slice_from_raw_parts_mut(self.as_mut_ptr(), self.len))
+ }
+ // RawVec handles deallocation
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl<T> const Default for Vec<T> {
+ /// Creates an empty `Vec<T>`.
+ fn default() -> Vec<T> {
+ Vec::new()
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Debug, A: Allocator> fmt::Debug for Vec<T, A> {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Debug::fmt(&**self, f)
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> AsRef<Vec<T, A>> for Vec<T, A> {
+ fn as_ref(&self) -> &Vec<T, A> {
+ self
+ }
+}
+
+#[stable(feature = "vec_as_mut", since = "1.5.0")]
+impl<T, A: Allocator> AsMut<Vec<T, A>> for Vec<T, A> {
+ fn as_mut(&mut self) -> &mut Vec<T, A> {
+ self
+ }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> AsRef<[T]> for Vec<T, A> {
+ fn as_ref(&self) -> &[T] {
+ self
+ }
+}
+
+#[stable(feature = "vec_as_mut", since = "1.5.0")]
+impl<T, A: Allocator> AsMut<[T]> for Vec<T, A> {
+ fn as_mut(&mut self) -> &mut [T] {
+ self
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone> From<&[T]> for Vec<T> {
+ /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(Vec::from(&[1, 2, 3][..]), vec![1, 2, 3]);
+ /// ```
+ #[cfg(not(test))]
+ fn from(s: &[T]) -> Vec<T> {
+ s.to_vec()
+ }
+ #[cfg(test)]
+ fn from(s: &[T]) -> Vec<T> {
+ crate::slice::to_vec(s, Global)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_mut", since = "1.19.0")]
+impl<T: Clone> From<&mut [T]> for Vec<T> {
+ /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(Vec::from(&mut [1, 2, 3][..]), vec![1, 2, 3]);
+ /// ```
+ #[cfg(not(test))]
+ fn from(s: &mut [T]) -> Vec<T> {
+ s.to_vec()
+ }
+ #[cfg(test)]
+ fn from(s: &mut [T]) -> Vec<T> {
+ crate::slice::to_vec(s, Global)
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_array", since = "1.44.0")]
+impl<T, const N: usize> From<[T; N]> for Vec<T> {
+ /// Allocate a `Vec<T>` and move `s`'s items into it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(Vec::from([1, 2, 3]), vec![1, 2, 3]);
+ /// ```
+ #[cfg(not(test))]
+ fn from(s: [T; N]) -> Vec<T> {
+ <[T]>::into_vec(box s)
+ }
+
+ #[cfg(test)]
+ fn from(s: [T; N]) -> Vec<T> {
+ crate::slice::into_vec(box s)
+ }
+}
+
+#[stable(feature = "vec_from_cow_slice", since = "1.14.0")]
+impl<'a, T> From<Cow<'a, [T]>> for Vec<T>
+where
+ [T]: ToOwned<Owned = Vec<T>>,
+{
+ /// Convert a clone-on-write slice into a vector.
+ ///
+ /// If `s` already owns a `Vec<T>`, it will be returned directly.
+ /// If `s` is borrowing a slice, a new `Vec<T>` will be allocated and
+ /// filled by cloning `s`'s items into it.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// # use std::borrow::Cow;
+ /// let o: Cow<[i32]> = Cow::Owned(vec![1, 2, 3]);
+ /// let b: Cow<[i32]> = Cow::Borrowed(&[1, 2, 3]);
+ /// assert_eq!(Vec::from(o), Vec::from(b));
+ /// ```
+ fn from(s: Cow<'a, [T]>) -> Vec<T> {
+ s.into_owned()
+ }
+}
+
+// note: test pulls in libstd, which causes errors here
+#[cfg(not(test))]
+#[stable(feature = "vec_from_box", since = "1.18.0")]
+impl<T, A: Allocator> From<Box<[T], A>> for Vec<T, A> {
+ /// Convert a boxed slice into a vector by transferring ownership of
+ /// the existing heap allocation.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// let b: Box<[i32]> = vec![1, 2, 3].into_boxed_slice();
+ /// assert_eq!(Vec::from(b), vec![1, 2, 3]);
+ /// ```
+ fn from(s: Box<[T], A>) -> Self {
+ s.into_vec()
+ }
+}
+
+// note: test pulls in libstd, which causes errors here
+#[cfg(not(no_global_oom_handling))]
+#[cfg(not(test))]
+#[stable(feature = "box_from_vec", since = "1.20.0")]
+impl<T, A: Allocator> From<Vec<T, A>> for Box<[T], A> {
+ /// Convert a vector into a boxed slice.
+ ///
+ /// If `v` has excess capacity, its items will be moved into a
+ /// newly-allocated buffer with exactly the right capacity.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());
+ /// ```
+ fn from(v: Vec<T, A>) -> Self {
+ v.into_boxed_slice()
+ }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl From<&str> for Vec<u8> {
+ /// Allocate a `Vec<u8>` and fill it with a UTF-8 string.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(Vec::from("123"), vec![b'1', b'2', b'3']);
+ /// ```
+ fn from(s: &str) -> Vec<u8> {
+ From::from(s.as_bytes())
+ }
+}
+
+#[stable(feature = "array_try_from_vec", since = "1.48.0")]
+impl<T, A: Allocator, const N: usize> TryFrom<Vec<T, A>> for [T; N] {
+ type Error = Vec<T, A>;
+
+ /// Gets the entire contents of the `Vec<T>` as an array,
+ /// if its size exactly matches that of the requested array.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// assert_eq!(vec![1, 2, 3].try_into(), Ok([1, 2, 3]));
+ /// assert_eq!(<Vec<i32>>::new().try_into(), Ok([]));
+ /// ```
+ ///
+ /// If the length doesn't match, the input comes back in `Err`:
+ /// ```
+ /// let r: Result<[i32; 4], _> = (0..10).collect::<Vec<_>>().try_into();
+ /// assert_eq!(r, Err(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));
+ /// ```
+ ///
+ /// If you're fine with just getting a prefix of the `Vec<T>`,
+ /// you can call [`.truncate(N)`](Vec::truncate) first.
+ /// ```
+ /// let mut v = String::from("hello world").into_bytes();
+ /// v.sort();
+ /// v.truncate(2);
+ /// let [a, b]: [_; 2] = v.try_into().unwrap();
+ /// assert_eq!(a, b' ');
+ /// assert_eq!(b, b'd');
+ /// ```
+ fn try_from(mut vec: Vec<T, A>) -> Result<[T; N], Vec<T, A>> {
+ if vec.len() != N {
+ return Err(vec);
+ }
+
+ // SAFETY: `.set_len(0)` is always sound.
+ unsafe { vec.set_len(0) };
+
+ // SAFETY: A `Vec`'s pointer is always aligned properly, and
+ // the alignment the array needs is the same as the items.
+ // We checked earlier that we have sufficient items.
+ // The items will not double-drop as the `set_len`
+ // tells the `Vec` not to also drop them.
+ let array = unsafe { ptr::read(vec.as_ptr() as *const [T; N]) };
+ Ok(array)
+ }
+}
diff --git a/rust/alloc/vec/partial_eq.rs b/rust/alloc/vec/partial_eq.rs
new file mode 100644
index 000000000000..50e140961050
--- /dev/null
+++ b/rust/alloc/vec/partial_eq.rs
@@ -0,0 +1,47 @@
+use crate::alloc::Allocator;
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::Cow;
+
+use super::Vec;
+
+macro_rules! __impl_slice_eq1 {
+ ([$($vars:tt)*] $lhs:ty, $rhs:ty $(where $ty:ty: $bound:ident)?, #[$stability:meta]) => {
+ #[$stability]
+ impl<T, U, $($vars)*> PartialEq<$rhs> for $lhs
+ where
+ T: PartialEq<U>,
+ $($ty: $bound)?
+ {
+ #[inline]
+ fn eq(&self, other: &$rhs) -> bool { self[..] == other[..] }
+ #[inline]
+ fn ne(&self, other: &$rhs) -> bool { self[..] != other[..] }
+ }
+ }
+}
+
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, Vec<U, A>, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, &[U], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, &mut [U], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator] &[T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
+__impl_slice_eq1! { [A: Allocator] &mut [T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, [U], #[stable(feature = "partialeq_vec_for_slice", since = "1.48.0")] }
+__impl_slice_eq1! { [A: Allocator] [T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_slice", since = "1.48.0")] }
+#[cfg(not(no_global_oom_handling))]
+__impl_slice_eq1! { [A: Allocator] Cow<'_, [T]>, Vec<U, A> where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+#[cfg(not(no_global_oom_handling))]
+__impl_slice_eq1! { [] Cow<'_, [T]>, &[U] where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+#[cfg(not(no_global_oom_handling))]
+__impl_slice_eq1! { [] Cow<'_, [T]>, &mut [U] where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator, const N: usize] Vec<T, A>, [U; N], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator, const N: usize] Vec<T, A>, &[U; N], #[stable(feature = "rust1", since = "1.0.0")] }
+
+// NOTE: some less important impls are omitted to reduce code bloat
+// FIXME(Centril): Reconsider this?
+//__impl_slice_eq1! { [const N: usize] Vec<A>, &mut [B; N], }
+//__impl_slice_eq1! { [const N: usize] [A; N], Vec<B>, }
+//__impl_slice_eq1! { [const N: usize] &[A; N], Vec<B>, }
+//__impl_slice_eq1! { [const N: usize] &mut [A; N], Vec<B>, }
+//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, [B; N], }
+//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &[B; N], }
+//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &mut [B; N], }
diff --git a/rust/alloc/vec/set_len_on_drop.rs b/rust/alloc/vec/set_len_on_drop.rs
new file mode 100644
index 000000000000..8b66bc812129
--- /dev/null
+++ b/rust/alloc/vec/set_len_on_drop.rs
@@ -0,0 +1,28 @@
+// Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
+//
+// The idea is: The length field in SetLenOnDrop is a local variable
+// that the optimizer will see does not alias with any stores through the Vec's data
+// pointer. This is a workaround for alias analysis issue #32155
+pub(super) struct SetLenOnDrop<'a> {
+ len: &'a mut usize,
+ local_len: usize,
+}
+
+impl<'a> SetLenOnDrop<'a> {
+ #[inline]
+ pub(super) fn new(len: &'a mut usize) -> Self {
+ SetLenOnDrop { local_len: *len, len }
+ }
+
+ #[inline]
+ pub(super) fn increment_len(&mut self, increment: usize) {
+ self.local_len += increment;
+ }
+}
+
+impl Drop for SetLenOnDrop<'_> {
+ #[inline]
+ fn drop(&mut self) {
+ *self.len = self.local_len;
+ }
+}
diff --git a/rust/alloc/vec/spec_extend.rs b/rust/alloc/vec/spec_extend.rs
new file mode 100644
index 000000000000..c3b4534096de
--- /dev/null
+++ b/rust/alloc/vec/spec_extend.rs
@@ -0,0 +1,87 @@
+use crate::alloc::Allocator;
+use core::iter::TrustedLen;
+use core::ptr::{self};
+use core::slice::{self};
+
+use super::{IntoIter, SetLenOnDrop, Vec};
+
+// Specialization trait used for Vec::extend
+pub(super) trait SpecExtend<T, I> {
+ fn spec_extend(&mut self, iter: I);
+}
+
+impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
+where
+ I: Iterator<Item = T>,
+{
+ default fn spec_extend(&mut self, iter: I) {
+ self.extend_desugared(iter)
+ }
+}
+
+impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
+where
+ I: TrustedLen<Item = T>,
+{
+ default fn spec_extend(&mut self, iterator: I) {
+ // This is the case for a TrustedLen iterator.
+ let (low, high) = iterator.size_hint();
+ if let Some(additional) = high {
+ debug_assert_eq!(
+ low,
+ additional,
+ "TrustedLen iterator's size hint is not exact: {:?}",
+ (low, high)
+ );
+ self.reserve(additional);
+ unsafe {
+ let mut ptr = self.as_mut_ptr().add(self.len());
+ let mut local_len = SetLenOnDrop::new(&mut self.len);
+ iterator.for_each(move |element| {
+ ptr::write(ptr, element);
+ ptr = ptr.offset(1);
+ // Since the loop executes user code which can panic we have to bump the pointer
+ // after each step.
+ // NB can't overflow since we would have had to alloc the address space
+ local_len.increment_len(1);
+ });
+ }
+ } else {
+ // Per TrustedLen contract a `None` upper bound means that the iterator length
+ // truly exceeds usize::MAX, which would eventually lead to a capacity overflow anyway.
+ // Since the other branch already panics eagerly (via `reserve()`) we do the same here.
+ // This avoids additional codegen for a fallback code path which would eventually
+ // panic anyway.
+ panic!("capacity overflow");
+ }
+ }
+}
+
+impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
+ fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
+ unsafe {
+ self.append_elements(iterator.as_slice() as _);
+ }
+ iterator.ptr = iterator.end;
+ }
+}
+
+impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
+where
+ I: Iterator<Item = &'a T>,
+ T: Clone,
+{
+ default fn spec_extend(&mut self, iterator: I) {
+ self.spec_extend(iterator.cloned())
+ }
+}
+
+impl<'a, T: 'a, A: Allocator + 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+where
+ T: Copy,
+{
+ fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
+ let slice = iterator.as_slice();
+ unsafe { self.append_elements(slice) };
+ }
+}
--
2.35.3
On Sat, May 07, 2022 at 01:06:18AM -0700, Kees Cook wrote:
> On Sat, May 07, 2022 at 07:23:58AM +0200, Miguel Ojeda wrote:
> > ## Patch series status
> >
> > The Rust support is still to be considered experimental. However,
> > support is good enough that kernel developers can start working on the
> > Rust abstractions for subsystems and write drivers and other modules.
>
> I'd really like to see this landed for a few reasons:
>
> - It's under active development, and I'd rather review the changes
> "normally", incrementally, etc. Right now it can be hard to re-review
> some of the "mostly the same each version" patches in the series.
>
> - I'd like to break the catch-22 of "ask for a new driver to be
> written in rust but the rust support isn't landed" vs "the rust
> support isn't landed because there aren't enough drivers". It
> really feels like "release early, release often" is needed here;
> it's hard to develop against -next. :)
+1 to both points. :-)
On Sat, May 07, 2022 at 07:23:58AM +0200, Miguel Ojeda wrote:
> ## Patch series status
>
> The Rust support is still to be considered experimental. However,
> support is good enough that kernel developers can start working on the
> Rust abstractions for subsystems and write drivers and other modules.
I'd really like to see this landed for a few reasons:
- It's under active development, and I'd rather review the changes
"normally", incrementally, etc. Right now it can be hard to re-review
some of the "mostly the same each version" patches in the series.
- I'd like to break the catch-22 of "ask for a new driver to be
written in rust but the rust support isn't landed" vs "the rust
support isn't landed because there aren't enough drivers". It
really feels like "release early, release often" is needed here;
it's hard to develop against -next. :)
Should we give it a try for this coming merge window?
--
Kees Cook
On Sat 2022-05-07 07:24:12, Miguel Ojeda wrote:
> From: Gary Guo <[email protected]>
>
> This patch adds a format specifier `%pA` to `vsprintf` which formats
> a pointer as `core::fmt::Arguments`. Doing so allows us to directly
> format to the internal buffer of `printf`, so we do not have to use
> a temporary buffer on the stack to pre-assemble the message on
> the Rust side.
>
> This specifier is intended only to be used from Rust and not for C, so
> `checkpatch.pl` is intentionally unchanged to catch any misuse.
>
> Co-developed-by: Alex Gaynor <[email protected]>
> Signed-off-by: Alex Gaynor <[email protected]>
> Co-developed-by: Wedson Almeida Filho <[email protected]>
> Signed-off-by: Wedson Almeida Filho <[email protected]>
> Signed-off-by: Gary Guo <[email protected]>
> Co-developed-by: Miguel Ojeda <[email protected]>
> Signed-off-by: Miguel Ojeda <[email protected]>
Feel free to use:
Acked-by: Petr Mladek <[email protected]>
See a comment below.
> ---
> lib/vsprintf.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 40d26a07a133..00f71f91d991 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -2270,6 +2270,9 @@ int __init no_hash_pointers_enable(char *str)
> }
> early_param("no_hash_pointers", no_hash_pointers_enable);
>
> +/* Used for Rust formatting ('%pA'). */
> +char *rust_fmt_argument(char *buf, char *end, void *ptr);
> +
> /*
> * Show a '%p' thing. A kernel extension is that the '%p' is followed
> * by an extra set of alphanumeric characters that are extended format
> @@ -2396,6 +2399,10 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
> *
> * Note: The default behaviour (unadorned %p) is to hash the address,
> * rendering it useful as a unique identifier.
> + *
> + * There is also a '%pA' format specifier, but it is only intended to be used
> + * from Rust code to format core::fmt::Arguments. Do *not* use it from C.
> + * See rust/kernel/print.rs for details.
> */
It would be great to document it also in
Documentation/core-api/printk-formats.rst
I am sorry that I did not mentioned it earlier.
Also the check in checkpatch.pl, mentioned in another reply, sounds
like a good idea.
Best Regards,
Petr
Hi Petr,
On Tue, May 10, 2022 at 10:38 AM Petr Mladek <[email protected]> wrote:
>
> Feel free to use:
>
> Acked-by: Petr Mladek <[email protected]>
Thanks!
> It would be great to document it also in
> Documentation/core-api/printk-formats.rst
> I am sorry that I did not mentioned it earlier.
Ah, definitely, I will add it.
> Also the check in checkpatch.pl, mentioned in another reply, sounds
> like a good idea.
+1
Cheers,
Miguel
On Sat, May 7, 2022 at 1:26 AM Miguel Ojeda <[email protected]> wrote:
>
> The `kunit_do_failed_assertion` function passes its
> `struct kunit_assert` argument to `kunit_fail`. This one,
> in turn, calls its `format` field passing the assert again
> as a `const` pointer.
>
> Therefore, the whole chain may be made `const`.
>
> Reviewed-by: Daniel Latypov <[email protected]>
> Signed-off-by: Miguel Ojeda <[email protected]>
Reviewed-by: Brendan Higgins <[email protected]>