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tools lib bpf: Retrive bpf_map through offset of bpf_map_def

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Add a new API to libbpf, caller is able to get bpf_map through the
offset of bpf_map_def to 'maps' section.

The API will be used to help jitted perf hook code find fd of a map.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Stringer <joe@ovn.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/20161126070354.141764-4-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Wang Nan 2016-11-26 07:03:27 +00:00 committed by Arnaldo Carvalho de Melo
parent 10931d2413
commit 5a6acad17d
2 changed files with 20 additions and 0 deletions
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12
tools/lib/bpf/libbpf.c
View File

@ -1524,3 +1524,15 @@ bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
}
return NULL;
}
struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
{
int i;
for (i = 0; i < obj->nr_maps; i++) {
if (obj->maps[i].offset == offset)
return &obj->maps[i];
}
return ERR_PTR(-ENOENT);
}

8
tools/lib/bpf/libbpf.h
View File

@ -24,6 +24,7 @@
#include <stdio.h>
#include <stdbool.h>
#include <linux/err.h>
#include <sys/types.h> // for size_t
enum libbpf_errno {
__LIBBPF_ERRNO__START = 4000,
@ -200,6 +201,13 @@ struct bpf_map;
struct bpf_map *
bpf_object__find_map_by_name(struct bpf_object *obj, const char *name);
/*
* Get bpf_map through the offset of corresponding struct bpf_map_def
* in the bpf object file.
*/
struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset);
struct bpf_map *
bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
#define bpf_map__for_each(pos, obj) \