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authorWang Nan <wangnan0@huawei.com>2015-11-27 03:47:36 -0500
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-11-27 19:59:53 -0500
commit561bbccac72d08babafaa33fd7fa9100ec4c9fb6 (patch)
treeb7dd063a6d2acc55d05ebfedf3396fcfbd9640bd
parent9d759a9b4ac2690077d8b21258e6e95c3e34bfa9 (diff)
tools lib bpf: Extract and collect map names from BPF object file
This patch collects name of maps in BPF object files and saves them into '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: He Kuang <hekuang@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: He Kuang <hekuang@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1448614067-197576-3-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r--tools/lib/bpf/libbpf.c65
-rw-r--r--tools/lib/bpf/libbpf.h3
2 files changed, 65 insertions, 3 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index f50982579aa8..a298614ad091 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -165,6 +165,7 @@ struct bpf_program {
165 165
166struct bpf_map { 166struct bpf_map {
167 int fd; 167 int fd;
168 char *name;
168 struct bpf_map_def def; 169 struct bpf_map_def def;
169 void *priv; 170 void *priv;
170 bpf_map_clear_priv_t clear_priv; 171 bpf_map_clear_priv_t clear_priv;
@@ -526,12 +527,46 @@ bpf_object__init_maps(struct bpf_object *obj, void *data,
526 return 0; 527 return 0;
527} 528}
528 529
530static void
531bpf_object__init_maps_name(struct bpf_object *obj, int maps_shndx)
532{
533 int i;
534 Elf_Data *symbols = obj->efile.symbols;
535
536 if (!symbols || maps_shndx < 0)
537 return;
538
539 for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
540 GElf_Sym sym;
541 size_t map_idx;
542 const char *map_name;
543
544 if (!gelf_getsym(symbols, i, &sym))
545 continue;
546 if (sym.st_shndx != maps_shndx)
547 continue;
548
549 map_name = elf_strptr(obj->efile.elf,
550 obj->efile.ehdr.e_shstrndx,
551 sym.st_name);
552 map_idx = sym.st_value / sizeof(struct bpf_map_def);
553 if (map_idx >= obj->nr_maps) {
554 pr_warning("index of map \"%s\" is buggy: %zu > %zu\n",
555 map_name, map_idx, obj->nr_maps);
556 continue;
557 }
558 obj->maps[map_idx].name = strdup(map_name);
559 pr_debug("map %zu is \"%s\"\n", map_idx,
560 obj->maps[map_idx].name);
561 }
562}
563
529static int bpf_object__elf_collect(struct bpf_object *obj) 564static int bpf_object__elf_collect(struct bpf_object *obj)
530{ 565{
531 Elf *elf = obj->efile.elf; 566 Elf *elf = obj->efile.elf;
532 GElf_Ehdr *ep = &obj->efile.ehdr; 567 GElf_Ehdr *ep = &obj->efile.ehdr;
533 Elf_Scn *scn = NULL; 568 Elf_Scn *scn = NULL;
534 int idx = 0, err = 0; 569 int idx = 0, err = 0, maps_shndx = -1;
535 570
536 /* Elf is corrupted/truncated, avoid calling elf_strptr. */ 571 /* Elf is corrupted/truncated, avoid calling elf_strptr. */
537 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) { 572 if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
@@ -581,10 +616,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
581 err = bpf_object__init_kversion(obj, 616 err = bpf_object__init_kversion(obj,
582 data->d_buf, 617 data->d_buf,
583 data->d_size); 618 data->d_size);
584 else if (strcmp(name, "maps") == 0) 619 else if (strcmp(name, "maps") == 0) {
585 err = bpf_object__init_maps(obj, data->d_buf, 620 err = bpf_object__init_maps(obj, data->d_buf,
586 data->d_size); 621 data->d_size);
587 else if (sh.sh_type == SHT_SYMTAB) { 622 maps_shndx = idx;
623 } else if (sh.sh_type == SHT_SYMTAB) {
588 if (obj->efile.symbols) { 624 if (obj->efile.symbols) {
589 pr_warning("bpf: multiple SYMTAB in %s\n", 625 pr_warning("bpf: multiple SYMTAB in %s\n",
590 obj->path); 626 obj->path);
@@ -625,6 +661,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
625 if (err) 661 if (err)
626 goto out; 662 goto out;
627 } 663 }
664
665 if (maps_shndx >= 0)
666 bpf_object__init_maps_name(obj, maps_shndx);
628out: 667out:
629 return err; 668 return err;
630} 669}
@@ -1086,6 +1125,7 @@ void bpf_object__close(struct bpf_object *obj)
1086 bpf_object__unload(obj); 1125 bpf_object__unload(obj);
1087 1126
1088 for (i = 0; i < obj->nr_maps; i++) { 1127 for (i = 0; i < obj->nr_maps; i++) {
1128 zfree(&obj->maps[i].name);
1089 if (obj->maps[i].clear_priv) 1129 if (obj->maps[i].clear_priv)
1090 obj->maps[i].clear_priv(&obj->maps[i], 1130 obj->maps[i].clear_priv(&obj->maps[i],
1091 obj->maps[i].priv); 1131 obj->maps[i].priv);
@@ -1266,6 +1306,13 @@ int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef)
1266 return 0; 1306 return 0;
1267} 1307}
1268 1308
1309const char *bpf_map__get_name(struct bpf_map *map)
1310{
1311 if (!map)
1312 return NULL;
1313 return map->name;
1314}
1315
1269int bpf_map__set_private(struct bpf_map *map, void *priv, 1316int bpf_map__set_private(struct bpf_map *map, void *priv,
1270 bpf_map_clear_priv_t clear_priv) 1317 bpf_map_clear_priv_t clear_priv)
1271{ 1318{
@@ -1318,3 +1365,15 @@ bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
1318 return NULL; 1365 return NULL;
1319 return &obj->maps[idx]; 1366 return &obj->maps[idx];
1320} 1367}
1368
1369struct bpf_map *
1370bpf_object__get_map_by_name(struct bpf_object *obj, const char *name)
1371{
1372 struct bpf_map *pos;
1373
1374 bpf_map__for_each(pos, obj) {
1375 if (strcmp(pos->name, name) == 0)
1376 return pos;
1377 }
1378 return NULL;
1379}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index ef631255dfaa..a51594c7b518 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -170,6 +170,8 @@ struct bpf_map_def {
170 * it is not a uapi header so no need to consider name clash. 170 * it is not a uapi header so no need to consider name clash.
171 */ 171 */
172struct bpf_map; 172struct bpf_map;
173struct bpf_map *
174bpf_object__get_map_by_name(struct bpf_object *obj, const char *name);
173 175
174struct bpf_map * 176struct bpf_map *
175bpf_map__next(struct bpf_map *map, struct bpf_object *obj); 177bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
@@ -180,6 +182,7 @@ bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
180 182
181int bpf_map__get_fd(struct bpf_map *map); 183int bpf_map__get_fd(struct bpf_map *map);
182int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef); 184int bpf_map__get_def(struct bpf_map *map, struct bpf_map_def *pdef);
185const char *bpf_map__get_name(struct bpf_map *map);
183 186
184typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *); 187typedef void (*bpf_map_clear_priv_t)(struct bpf_map *, void *);
185int bpf_map__set_private(struct bpf_map *map, void *priv, 188int bpf_map__set_private(struct bpf_map *map, void *priv,