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Commit 5a6acad1 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
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tools lib bpf: Retrive bpf_map through offset of bpf_map_def 



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: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarAlexei 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 10931d24

tools/lib/bpf/libbpf.c

+12 −0
Original line number Diff line number Diff line
@@ -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);

}

tools/lib/bpf/libbpf.h

+8 −0
Original line number Diff line number Diff line
@@ -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)		\