diff options
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 142 |
1 files changed, 98 insertions, 44 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b699aea9a025..96a2b2ff1212 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -185,6 +185,7 @@ struct bpf_program { struct bpf_map { int fd; char *name; + size_t offset; struct bpf_map_def def; void *priv; bpf_map_clear_priv_t clear_priv; @@ -513,57 +514,106 @@ bpf_object__init_kversion(struct bpf_object *obj, } static int -bpf_object__init_maps(struct bpf_object *obj, void *data, - size_t size) +bpf_object__validate_maps(struct bpf_object *obj) { - size_t nr_maps; int i; - nr_maps = size / sizeof(struct bpf_map_def); - if (!data || !nr_maps) { - pr_debug("%s doesn't need map definition\n", - obj->path); + /* + * If there's only 1 map, the only error case should have been + * catched in bpf_object__init_maps(). + */ + if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1)) return 0; - } - pr_debug("maps in %s: %zd bytes\n", obj->path, size); + for (i = 1; i < obj->nr_maps; i++) { + const struct bpf_map *a = &obj->maps[i - 1]; + const struct bpf_map *b = &obj->maps[i]; - obj->maps = calloc(nr_maps, sizeof(obj->maps[0])); - if (!obj->maps) { - pr_warning("alloc maps for object failed\n"); - return -ENOMEM; + if (b->offset - a->offset < sizeof(struct bpf_map_def)) { + pr_warning("corrupted map section in %s: map \"%s\" too small\n", + obj->path, a->name); + return -EINVAL; + } } - obj->nr_maps = nr_maps; - - for (i = 0; i < nr_maps; i++) { - struct bpf_map_def *def = &obj->maps[i].def; + return 0; +} - /* - * fill all fd with -1 so won't close incorrect - * fd (fd=0 is stdin) when failure (zclose won't close - * negative fd)). - */ - obj->maps[i].fd = -1; +static int compare_bpf_map(const void *_a, const void *_b) +{ + const struct bpf_map *a = _a; + const struct bpf_map *b = _b; - /* Save map definition into obj->maps */ - *def = ((struct bpf_map_def *)data)[i]; - } - return 0; + return a->offset - b->offset; } static int -bpf_object__init_maps_name(struct bpf_object *obj) +bpf_object__init_maps(struct bpf_object *obj) { - int i; + int i, map_idx, nr_maps = 0; + Elf_Scn *scn; + Elf_Data *data; Elf_Data *symbols = obj->efile.symbols; - if (!symbols || obj->efile.maps_shndx < 0) + if (obj->efile.maps_shndx < 0) + return -EINVAL; + if (!symbols) + return -EINVAL; + + scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx); + if (scn) + data = elf_getdata(scn, NULL); + if (!scn || !data) { + pr_warning("failed to get Elf_Data from map section %d\n", + obj->efile.maps_shndx); return -EINVAL; + } + /* + * Count number of maps. Each map has a name. + * Array of maps is not supported: only the first element is + * considered. + * + * TODO: Detect array of map and report error. + */ for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { GElf_Sym sym; - size_t map_idx; + + if (!gelf_getsym(symbols, i, &sym)) + continue; + if (sym.st_shndx != obj->efile.maps_shndx) + continue; + nr_maps++; + } + + /* Alloc obj->maps and fill nr_maps. */ + pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path, + nr_maps, data->d_size); + + if (!nr_maps) + return 0; + + obj->maps = calloc(nr_maps, sizeof(obj->maps[0])); + if (!obj->maps) { + pr_warning("alloc maps for object failed\n"); + return -ENOMEM; + } + obj->nr_maps = nr_maps; + + /* + * fill all fd with -1 so won't close incorrect + * fd (fd=0 is stdin) when failure (zclose won't close + * negative fd)). + */ + for (i = 0; i < nr_maps; i++) + obj->maps[i].fd = -1; + + /* + * Fill obj->maps using data in "maps" section. + */ + for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) { + GElf_Sym sym; const char *map_name; + struct bpf_map_def *def; if (!gelf_getsym(symbols, i, &sym)) continue; @@ -573,21 +623,27 @@ bpf_object__init_maps_name(struct bpf_object *obj) map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx, sym.st_name); - map_idx = sym.st_value / sizeof(struct bpf_map_def); - 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].offset = sym.st_value; + if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) { + pr_warning("corrupted maps section in %s: last map \"%s\" too small\n", + obj->path, map_name); + return -EINVAL; } + obj->maps[map_idx].name = strdup(map_name); if (!obj->maps[map_idx].name) { pr_warning("failed to alloc map name\n"); return -ENOMEM; } - pr_debug("map %zu is \"%s\"\n", map_idx, + pr_debug("map %d is \"%s\"\n", map_idx, obj->maps[map_idx].name); + def = (struct bpf_map_def *)(data->d_buf + sym.st_value); + obj->maps[map_idx].def = *def; + map_idx++; } - return 0; + + qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map); + return bpf_object__validate_maps(obj); } static int bpf_object__elf_collect(struct bpf_object *obj) @@ -645,11 +701,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj) err = bpf_object__init_kversion(obj, data->d_buf, data->d_size); - else if (strcmp(name, "maps") == 0) { - err = bpf_object__init_maps(obj, data->d_buf, - data->d_size); + else if (strcmp(name, "maps") == 0) obj->efile.maps_shndx = idx; - } else if (sh.sh_type == SHT_SYMTAB) { + else if (sh.sh_type == SHT_SYMTAB) { if (obj->efile.symbols) { pr_warning("bpf: multiple SYMTAB in %s\n", obj->path); @@ -698,7 +752,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj) return LIBBPF_ERRNO__FORMAT; } if (obj->efile.maps_shndx >= 0) - err = bpf_object__init_maps_name(obj); + err = bpf_object__init_maps(obj); out: return err; } @@ -807,7 +861,7 @@ bpf_object__create_maps(struct bpf_object *obj) zclose(obj->maps[j].fd); return err; } - pr_debug("create map: fd=%d\n", *pfd); + pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd); } return 0; |