Hi Wang,
On Fri, Nov 27, 2015 at 08:47:36AM +0000, Wang Nan wrote:
This patch collects name of maps in BPF object files and saves them intoIt means that each map name is saved in section header string table?
'maps' field in 'struct bpf_object'. 'bpf_object__get_map_by_name' is
introduced to retrive fd and definitions of a map through its name.
Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
tools/lib/bpf/libbpf.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++---
tools/lib/bpf/libbpf.h | 3 +++
2 files changed, 65 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index f509825..a298614 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -165,6 +165,7 @@ struct bpf_program {
struct bpf_map {
int fd;
+ char *name;
struct bpf_map_def def;
void *priv;
bpf_map_clear_priv_t clear_priv;
@@ -526,12 +527,46 @@ bpf_object__init_maps(struct bpf_object *obj, void *data,
return 0;
}
+static void
+bpf_object__init_maps_name(struct bpf_object *obj, int maps_shndx)
+{
+ int i;
+ Elf_Data *symbols = obj->efile.symbols;
+
+ if (!symbols || maps_shndx < 0)
+ return;
+
+ for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
+ GElf_Sym sym;
+ size_t map_idx;
+ const char *map_name;
+
+ if (!gelf_getsym(symbols, i, &sym))
+ continue;
+ if (sym.st_shndx != maps_shndx)
+ continue;
+
+ map_name = elf_strptr(obj->efile.elf,
+ obj->efile.ehdr.e_shstrndx,
+ sym.st_name);
+ map_idx = sym.st_value / sizeof(struct bpf_map_def);You need to check the return value.
+ if (map_idx >= obj->nr_maps) {
+ pr_warning("index of map \"%s\" is buggy: %zu > %zu\n",
+ map_name, map_idx, obj->nr_maps);
+ continue;
+ }
+ obj->maps[map_idx].name = strdup(map_name);