Commit 01af3bf0 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
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libbpf: Expose BPF program's function name 



Add APIs to get BPF program function name, as opposed to bpf_program__title(),
which returns BPF program function's section name. Function name has a benefit
of being a valid C identifier and uniquely identifies a specific BPF program,
while section name can be duplicated across multiple independent BPF programs.

Add also bpf_object__find_program_by_name(), similar to
bpf_object__find_program_by_title(), to facilitate looking up BPF programs by
their C function names.

Convert one of selftests to new API for look up.

Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191214014341.3442258-9-andriin@fb.com
parent 9f81654e

tools/lib/bpf/libbpf.c

+23 −5
Original line number Diff line number Diff line
@@ -209,8 +209,8 @@ static const char * const libbpf_type_to_btf_name[] = { 
};



struct bpf_map {

	int fd;

	char *name;

	int fd;

	int sec_idx;

	size_t sec_offset;

	int map_ifindex;
@@ -1384,7 +1384,7 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, 
}



static int bpf_object__init_maps(struct bpf_object *obj,

				 struct bpf_object_open_opts *opts)

				 const struct bpf_object_open_opts *opts)

{

	const char *pin_root_path = OPTS_GET(opts, pin_root_path, NULL);

	bool strict = !OPTS_GET(opts, relaxed_maps, false);
@@ -1748,6 +1748,19 @@ bpf_object__find_program_by_title(const struct bpf_object *obj, 
	return NULL;

}



struct bpf_program *

bpf_object__find_program_by_name(const struct bpf_object *obj,

				 const char *name)

{

	struct bpf_program *prog;



	bpf_object__for_each_program(prog, obj) {

		if (!strcmp(prog->name, name))

			return prog;

	}

	return NULL;

}



static bool bpf_object__shndx_is_data(const struct bpf_object *obj,

				      int shndx)

{
@@ -3894,7 +3907,7 @@ static int libbpf_find_attach_btf_id(const char *name, 
				     __u32 attach_prog_fd);

static struct bpf_object *

__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,

		   struct bpf_object_open_opts *opts)

		   const struct bpf_object_open_opts *opts)

{

	struct bpf_program *prog;

	struct bpf_object *obj;
@@ -4003,7 +4016,7 @@ struct bpf_object *bpf_object__open(const char *path) 
}



struct bpf_object *

bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts)

bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)

{

	if (!path)

		return ERR_PTR(-EINVAL);
@@ -4015,7 +4028,7 @@ bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts) 


struct bpf_object *

bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,

		     struct bpf_object_open_opts *opts)

		     const struct bpf_object_open_opts *opts)

{

	if (!obj_buf || obj_buf_sz == 0)

		return ERR_PTR(-EINVAL);
@@ -4820,6 +4833,11 @@ void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex) 
	prog->prog_ifindex = ifindex;

}



const char *bpf_program__name(const struct bpf_program *prog)

{

	return prog->name;

}



const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)

{

	const char *title;

tools/lib/bpf/libbpf.h

+7 −2
Original line number Diff line number Diff line
@@ -90,10 +90,10 @@ struct bpf_object_open_opts { 


LIBBPF_API struct bpf_object *bpf_object__open(const char *path);

LIBBPF_API struct bpf_object *

bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts);

bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts);

LIBBPF_API struct bpf_object *

bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,

		     struct bpf_object_open_opts *opts);

		     const struct bpf_object_open_opts *opts);



/* deprecated bpf_object__open variants */

LIBBPF_API struct bpf_object *
@@ -132,6 +132,7 @@ struct bpf_object_load_attr { 
LIBBPF_API int bpf_object__load(struct bpf_object *obj);

LIBBPF_API int bpf_object__load_xattr(struct bpf_object_load_attr *attr);

LIBBPF_API int bpf_object__unload(struct bpf_object *obj);



LIBBPF_API const char *bpf_object__name(const struct bpf_object *obj);

LIBBPF_API unsigned int bpf_object__kversion(const struct bpf_object *obj);
@@ -142,6 +143,9 @@ LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj); 
LIBBPF_API struct bpf_program *

bpf_object__find_program_by_title(const struct bpf_object *obj,

				  const char *title);

LIBBPF_API struct bpf_program *

bpf_object__find_program_by_name(const struct bpf_object *obj,

				 const char *name);



LIBBPF_API struct bpf_object *bpf_object__next(struct bpf_object *prev);

#define bpf_object__for_each_safe(pos, tmp)			\
@@ -185,6 +189,7 @@ LIBBPF_API void *bpf_program__priv(const struct bpf_program *prog); 
LIBBPF_API void bpf_program__set_ifindex(struct bpf_program *prog,

					 __u32 ifindex);



LIBBPF_API const char *bpf_program__name(const struct bpf_program *prog);

LIBBPF_API const char *bpf_program__title(const struct bpf_program *prog,

					  bool needs_copy);

tools/lib/bpf/libbpf.map

+2 −0
Original line number Diff line number Diff line
@@ -212,6 +212,8 @@ LIBBPF_0.0.6 { 
LIBBPF_0.0.7 {

	global:

		btf_dump__emit_type_decl;

		bpf_object__find_program_by_name;

		bpf_program__attach;

		bpf_program__name;

		btf__align_of;

} LIBBPF_0.0.6;

tools/testing/selftests/bpf/prog_tests/rdonly_maps.c

+4 −7
Original line number Diff line number Diff line
@@ -16,14 +16,11 @@ struct rdonly_map_subtest { 


void test_rdonly_maps(void)

{

	const char *prog_name_skip_loop = "raw_tracepoint/sys_enter:skip_loop";

	const char *prog_name_part_loop = "raw_tracepoint/sys_enter:part_loop";

	const char *prog_name_full_loop = "raw_tracepoint/sys_enter:full_loop";

	const char *file = "test_rdonly_maps.o";

	struct rdonly_map_subtest subtests[] = {

		{ "skip loop", prog_name_skip_loop, 0, 0 },

		{ "part loop", prog_name_part_loop, 3, 2 + 3 + 4 },

		{ "full loop", prog_name_full_loop, 4, 2 + 3 + 4 + 5 },

		{ "skip loop", "skip_loop", 0, 0 },

		{ "part loop", "part_loop", 3, 2 + 3 + 4 },

		{ "full loop", "full_loop", 4, 2 + 3 + 4 + 5 },

	};

	int i, err, zero = 0, duration = 0;

	struct bpf_link *link = NULL;
@@ -50,7 +47,7 @@ void test_rdonly_maps(void) 
		if (!test__start_subtest(t->subtest_name))

			continue;



		prog = bpf_object__find_program_by_title(obj, t->prog_name);

		prog = bpf_object__find_program_by_name(obj, t->prog_name);

		if (CHECK(!prog, "find_prog", "prog '%s' not found\n",

			  t->prog_name))

			goto cleanup;

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