Adds libbpf APIs for disabling auto-attach for individual functions.
This is motivated by the use case of cgroup iter [1]. Some iter
types require their parameters to be non-zero, therefore applying
auto-attach on them will fail. With these two new APIs, users who
want to use auto-attach and these types of iters can disable
auto-attach on the program and perform manual attach.
[1] https://lore.kernel.org/bpf/CAEf4BzZ+a2uDo_t6kGBziqdz--m2gh2_EUwkGLDtMd65uwxUjA@mail.gmail.com/
Signed-off-by: Hao Luo <[email protected]>
---
tools/lib/bpf/libbpf.c | 15 ++++++++++++++-
tools/lib/bpf/libbpf.h | 2 ++
tools/lib/bpf/libbpf.map | 2 ++
3 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index aa05a99b913d..0159a43c7efd 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -417,6 +417,7 @@ struct bpf_program {
int fd;
bool autoload;
+ bool autoattach;
bool mark_btf_static;
enum bpf_prog_type type;
enum bpf_attach_type expected_attach_type;
@@ -755,6 +756,8 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog,
prog->autoload = true;
}
+ prog->autoattach = true;
+
/* inherit object's log_level */
prog->log_level = obj->log_level;
@@ -8314,6 +8317,16 @@ int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
return 0;
}
+bool bpf_program__autoattach(const struct bpf_program *prog)
+{
+ return prog->autoattach;
+}
+
+void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach)
+{
+ prog->autoattach = autoattach;
+}
+
const struct bpf_insn *bpf_program__insns(const struct bpf_program *prog)
{
return prog->insns;
@@ -12346,7 +12359,7 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
struct bpf_program *prog = *s->progs[i].prog;
struct bpf_link **link = s->progs[i].link;
- if (!prog->autoload)
+ if (!prog->autoload || !prog->autoattach)
continue;
/* auto-attaching not supported for this program */
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 61493c4cddac..88a1ac34b12a 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -260,6 +260,8 @@ LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog);
LIBBPF_API const char *bpf_program__section_name(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__autoload(const struct bpf_program *prog);
LIBBPF_API int bpf_program__set_autoload(struct bpf_program *prog, bool autoload);
+LIBBPF_API bool bpf_program__autoattach(const struct bpf_program *prog);
+LIBBPF_API void bpf_program__set_autoattach(struct bpf_program *prog, bool autoattach);
struct bpf_insn;
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 119e6e1ea7f1..2b928dc21af0 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -358,6 +358,8 @@ LIBBPF_1.0.0 {
bpf_obj_get_opts;
bpf_prog_query_opts;
bpf_program__attach_ksyscall;
+ bpf_program__autoattach;
+ bpf_program__set_autoattach;
btf__add_enum64;
btf__add_enum64_value;
libbpf_bpf_attach_type_str;
--
2.37.1.595.g718a3a8f04-goog
Adds test for libbpf APIs that toggle bpf program auto-attaching.
Signed-off-by: Hao Luo <[email protected]>
---
.../selftests/bpf/prog_tests/autoattach.c | 30 +++++++++++++++++++
.../selftests/bpf/progs/test_autoattach.c | 23 ++++++++++++++
2 files changed, 53 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/autoattach.c
create mode 100644 tools/testing/selftests/bpf/progs/test_autoattach.c
diff --git a/tools/testing/selftests/bpf/prog_tests/autoattach.c b/tools/testing/selftests/bpf/prog_tests/autoattach.c
new file mode 100644
index 000000000000..b34b5945d297
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/autoattach.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Google */
+
+#include <test_progs.h>
+#include "test_autoattach.skel.h"
+
+void test_autoattach(void)
+{
+ struct test_autoattach* skel;
+
+ skel = test_autoattach__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+ goto cleanup;
+
+ /* disable auto-attach for prog2 */
+ bpf_program__set_autoattach(skel->progs.prog2, false);
+ ASSERT_TRUE(bpf_program__autoattach(skel->progs.prog1), "autoattach_prog1");
+ ASSERT_FALSE(bpf_program__autoattach(skel->progs.prog2), "autoattach_prog2");
+ if (!ASSERT_OK(test_autoattach__attach(skel), "skel_attach"))
+ goto cleanup;
+
+ usleep(1);
+
+ ASSERT_TRUE(skel->bss->prog1_called, "attached_prog1");
+ ASSERT_FALSE(skel->bss->prog2_called, "attached_prog2");
+
+cleanup:
+ test_autoattach__destroy(skel);
+}
+
diff --git a/tools/testing/selftests/bpf/progs/test_autoattach.c b/tools/testing/selftests/bpf/progs/test_autoattach.c
new file mode 100644
index 000000000000..11a44493ebce
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_autoattach.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Google */
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+
+bool prog1_called = false;
+bool prog2_called = false;
+
+SEC("raw_tp/sys_enter")
+int prog1(const void *ctx)
+{
+ prog1_called = true;
+ return 0;
+}
+
+SEC("raw_tp/sys_exit")
+int prog2(const void *ctx)
+{
+ prog2_called = true;
+ return 0;
+}
+
--
2.37.1.595.g718a3a8f04-goog
Hello:
This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <[email protected]>:
On Tue, 16 Aug 2022 16:40:11 -0700 you wrote:
> Adds libbpf APIs for disabling auto-attach for individual functions.
> This is motivated by the use case of cgroup iter [1]. Some iter
> types require their parameters to be non-zero, therefore applying
> auto-attach on them will fail. With these two new APIs, users who
> want to use auto-attach and these types of iters can disable
> auto-attach on the program and perform manual attach.
>
> [...]
Here is the summary with links:
- [bpf-next,v2,1/2] libbpf: Allows disabling auto attach
https://git.kernel.org/bpf/bpf-next/c/43cb8cbadffa
- [bpf-next,v2,2/2] selftests/bpf: Tests libbpf autoattach APIs
https://git.kernel.org/bpf/bpf-next/c/738a2f2f9130
You are awesome, thank you!
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