When linking statically, libraries may require other dependencies to be
included to ld flags. In particular, libelf may require libzstd. Use
pkg-config to determine such dependencies.
Signed-off-by: Akihiko Odaki <[email protected]>
---
V2 -> V3: Added missing "echo".
V1 -> V2: Implemented fallback, referring to HOSTPKG_CONFIG.
tools/testing/selftests/bpf/Makefile | 4 +++-
tools/testing/selftests/bpf/README.rst | 2 +-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index caede9b574cb..0b4ce6266bfc 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -4,6 +4,7 @@ include ../../../scripts/Makefile.arch
include ../../../scripts/Makefile.include
CXX ?= $(CROSS_COMPILE)g++
+PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
CURDIR := $(abspath .)
TOOLSDIR := $(abspath ../../..)
@@ -31,7 +32,8 @@ CFLAGS += -g -O0 -rdynamic -Wall -Werror $(GENFLAGS) $(SAN_CFLAGS) \
-I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR) \
-I$(TOOLSINCDIR) -I$(APIDIR) -I$(OUTPUT)
LDFLAGS += $(SAN_LDFLAGS)
-LDLIBS += -lelf -lz -lrt -lpthread
+LDLIBS += $(shell $(PKG_CONFIG) --libs libelf zlib || echo -lelf -lz) \
+ -lrt -lpthread
ifneq ($(LLVM),)
# Silence some warnings when compiled with clang
diff --git a/tools/testing/selftests/bpf/README.rst b/tools/testing/selftests/bpf/README.rst
index cb9b95702ac6..9af79c7a9b58 100644
--- a/tools/testing/selftests/bpf/README.rst
+++ b/tools/testing/selftests/bpf/README.rst
@@ -77,7 +77,7 @@ In case of linker errors when running selftests, try using static linking:
.. code-block:: console
- $ LDLIBS=-static vmtest.sh
+ $ LDLIBS=-static PKG_CONFIG='pkg-config --static' vmtest.sh
.. note:: Some distros may not support static linking.
--
2.42.0
On 10/16/23 2:43 PM, Akihiko Odaki wrote:
> When linking statically, libraries may require other dependencies to be
> included to ld flags. In particular, libelf may require libzstd. Use
> pkg-config to determine such dependencies.
>
> Signed-off-by: Akihiko Odaki <[email protected]>
> ---
> V2 -> V3: Added missing "echo".
> V1 -> V2: Implemented fallback, referring to HOSTPKG_CONFIG.
Same issue in v3. Please don't resend your patches too quickly, but properly set up an
environment where you can test that this fallback works first :
https://github.com/kernel-patches/bpf/actions/runs/6533309175/job/17738285759
[...]
/bin/sh: 1: pkg-config: not found
/bin/sh: 1: -lelf: not found
BINARY test_sysctl
/usr/bin/x86_64-linux-gnu-ld: /usr/bin/x86_64-linux-gnu-ld: DWARF error: invalid or unhandled FORM value: 0x25
/tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `bpf_object_open':
libbpf.c:(.text+0x2871): undefined reference to `elf_version'
/usr/bin/x86_64-linux-gnu-ld: /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `bpf_object__elf_finish':
libbpf.c:(.text+0x4ccf): undefined reference to `elf_end'
/usr/bin/x86_64-linux-gnu-ld: /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `elf_find_func_offset_from_archive':
libbpf.c:(.text+0xb419): undefined reference to `elf_memory'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0xb447): undefined reference to `elf_errmsg'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0xb4e2): undefined reference to `elf_end'
/usr/bin/x86_64-linux-gnu-ld: /tmp/work/bpf/bpf/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o): in function `bpf_object__elf_init':
libbpf.c:(.text+0x10b02): undefined reference to `elf_memory'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10bae): undefined reference to `elf_begin'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10bdd): undefined reference to `elf_errmsg'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10c1b): undefined reference to `elf_kind'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10c54): undefined reference to `gelf_getclass'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10c8d): undefined reference to `elf64_getehdr'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10cd1): undefined reference to `elf_errmsg'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d0f): undefined reference to `elf_getshdrstrndx'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d38): undefined reference to `elf_errmsg'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d72): undefined reference to `elf_getscn'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10d7e): undefined reference to `elf_rawdata'
/usr/bin/x86_64-linux-gnu-ld: libbpf.c:(.text+0x10da8): undefined reference to `elf_errmsg'
On 2023/10/16 21:52, Daniel Borkmann wrote:
> On 10/16/23 2:43 PM, Akihiko Odaki wrote:
>> When linking statically, libraries may require other dependencies to be
>> included to ld flags. In particular, libelf may require libzstd. Use
>> pkg-config to determine such dependencies.
>>
>> Signed-off-by: Akihiko Odaki <[email protected]>
>> ---
>> V2 -> V3: Added missing "echo".
>> V1 -> V2: Implemented fallback, referring to HOSTPKG_CONFIG.
>
> Same issue in v3. Please don't resend your patches too quickly, but
> properly set up an
> environment where you can test that this fallback works first :
>
> https://github.com/kernel-patches/bpf/actions/runs/6533309175/job/17738285759
I think you are looking at a wrong run. The run checks out:
https://github.com/kernel-patches/bpf/commit/0c184cb0b561d2fb60b2dc79c2917cd7ff8cd8a2
This is v2. I think the correct one is:
https://github.com/kernel-patches/bpf/actions/runs/6533797864
That said, I found spurious error messages with the run. I tested it by
setting PKG_CONFIG=false, but I should have tested it with
PKG_CONFIG=a-command-that-does-not-exist. Now I sent v4, which does no
longer emit noisy error messages and is properly tested.