[PATCH bpf-next 1/6] libbpf: Add a helper for retrieving a map fd for a given name
From: Maciej Fijalkowski <hidden>
Date: 2019-01-17 01:02:09
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
XDP samples are mostly cooperating with eBPF maps through their file descriptors. In case of a eBPF program that contains multiple maps it might be tiresome to iterate through them and call bpf_map__fd for each one. Add a helper mostly based on bpf_object__find_map_by_name, but instead of returning the struct bpf_map pointer, return map fd. Bump libbpf ABI version to 0.0.2. Suggested-by: Jakub Kicinski <redacted> Signed-off-by: Maciej Fijalkowski <redacted> Reviewed-by: Jakub Kicinski <redacted> --- tools/lib/bpf/libbpf.c | 12 ++++++++++++ tools/lib/bpf/libbpf.h | 3 +++ tools/lib/bpf/libbpf.map | 4 ++++ 3 files changed, 19 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 169e347c76f6..dc838bea403f 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c@@ -2840,6 +2840,18 @@ bpf_object__find_map_by_name(struct bpf_object *obj, const char *name) return NULL; } +int +bpf_object__find_map_fd_by_name(struct bpf_object *obj, const char *name) +{ + struct bpf_map *pos; + + bpf_map__for_each(pos, obj) { + if (pos->name && !strcmp(pos->name, name)) + return bpf_map__fd(pos); + } + return -ENOENT; +} + struct bpf_map * bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) {
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 5f68d7b75215..7f10d36abdde 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h@@ -264,6 +264,9 @@ struct bpf_map; LIBBPF_API struct bpf_map * bpf_object__find_map_by_name(struct bpf_object *obj, const char *name); +LIBBPF_API int +bpf_object__find_map_fd_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.
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index cd02cd4e2cc3..7c59e4f64082 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map@@ -124,3 +124,7 @@ LIBBPF_0.0.1 { local: *; }; +LIBBPF_0.0.2 { + global: + bpf_object__find_map_fd_by_name; +} LIBBPF_0.0.1;
--
2.16.1