diff options
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 385 |
1 files changed, 305 insertions, 80 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c80f316f1320..7aa2a2a22cef 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -227,6 +227,8 @@ struct bpf_map { void *priv; bpf_map_clear_priv_t clear_priv; enum libbpf_map_type libbpf_type; + char *pin_path; + bool pinned; }; struct bpf_secdata { @@ -1091,10 +1093,32 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, return true; } +static int build_map_pin_path(struct bpf_map *map, const char *path) +{ + char buf[PATH_MAX]; + int err, len; + + if (!path) + path = "/sys/fs/bpf"; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map)); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + + err = bpf_map__set_pin_path(map, buf); + if (err) + return err; + + return 0; +} + static int bpf_object__init_user_btf_map(struct bpf_object *obj, const struct btf_type *sec, int var_idx, int sec_idx, - const Elf_Data *data, bool strict) + const Elf_Data *data, bool strict, + const char *pin_root_path) { const struct btf_type *var, *def, *t; const struct btf_var_secinfo *vi; @@ -1269,6 +1293,30 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, } map->def.value_size = sz; map->btf_value_type_id = t->type; + } else if (strcmp(name, "pinning") == 0) { + __u32 val; + int err; + + if (!get_map_field_int(map_name, obj->btf, def, m, + &val)) + return -EINVAL; + pr_debug("map '%s': found pinning = %u.\n", + map_name, val); + + if (val != LIBBPF_PIN_NONE && + val != LIBBPF_PIN_BY_NAME) { + pr_warn("map '%s': invalid pinning value %u.\n", + map_name, val); + return -EINVAL; + } + if (val == LIBBPF_PIN_BY_NAME) { + err = build_map_pin_path(map, pin_root_path); + if (err) { + pr_warn("map '%s': couldn't build pin path.\n", + map_name); + return err; + } + } } else { if (strict) { pr_warn("map '%s': unknown field '%s'.\n", @@ -1288,7 +1336,8 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, return 0; } -static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict) +static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, + const char *pin_root_path) { const struct btf_type *sec = NULL; int nr_types, i, vlen, err; @@ -1330,7 +1379,7 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict) for (i = 0; i < vlen; i++) { err = bpf_object__init_user_btf_map(obj, sec, i, obj->efile.btf_maps_shndx, - data, strict); + data, strict, pin_root_path); if (err) return err; } @@ -1338,7 +1387,8 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict) return 0; } -static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps) +static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps, + const char *pin_root_path) { bool strict = !relaxed_maps; int err; @@ -1347,7 +1397,7 @@ static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps) if (err) return err; - err = bpf_object__init_user_btf_maps(obj, strict); + err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path); if (err) return err; @@ -1536,7 +1586,8 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) return 0; } -static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps) +static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps, + const char *pin_root_path) { Elf *elf = obj->efile.elf; GElf_Ehdr *ep = &obj->efile.ehdr; @@ -1671,7 +1722,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps) } err = bpf_object__init_btf(obj, btf_data, btf_ext_data); if (!err) - err = bpf_object__init_maps(obj, relaxed_maps); + err = bpf_object__init_maps(obj, relaxed_maps, pin_root_path); if (!err) err = bpf_object__sanitize_and_load_btf(obj); if (!err) @@ -1917,16 +1968,22 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) return -errno; new_fd = open("/", O_RDONLY | O_CLOEXEC); - if (new_fd < 0) + if (new_fd < 0) { + err = -errno; goto err_free_new_name; + } new_fd = dup3(fd, new_fd, O_CLOEXEC); - if (new_fd < 0) + if (new_fd < 0) { + err = -errno; goto err_close_new_fd; + } err = zclose(map->fd); - if (err) + if (err) { + err = -errno; goto err_close_new_fd; + } free(map->name); map->fd = new_fd; @@ -1945,7 +2002,7 @@ err_close_new_fd: close(new_fd); err_free_new_name: free(new_name); - return -errno; + return err; } int bpf_map__resize(struct bpf_map *map, __u32 max_entries) @@ -2121,6 +2178,66 @@ bpf_object__probe_caps(struct bpf_object *obj) return 0; } +static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) +{ + struct bpf_map_info map_info = {}; + char msg[STRERR_BUFSIZE]; + __u32 map_info_len; + + map_info_len = sizeof(map_info); + + if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) { + pr_warn("failed to get map info for map FD %d: %s\n", + map_fd, libbpf_strerror_r(errno, msg, sizeof(msg))); + return false; + } + + return (map_info.type == map->def.type && + map_info.key_size == map->def.key_size && + map_info.value_size == map->def.value_size && + map_info.max_entries == map->def.max_entries && + map_info.map_flags == map->def.map_flags); +} + +static int +bpf_object__reuse_map(struct bpf_map *map) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + int err, pin_fd; + + pin_fd = bpf_obj_get(map->pin_path); + if (pin_fd < 0) { + err = -errno; + if (err == -ENOENT) { + pr_debug("found no pinned map to reuse at '%s'\n", + map->pin_path); + return 0; + } + + cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warn("couldn't retrieve pinned map '%s': %s\n", + map->pin_path, cp); + return err; + } + + if (!map_is_reuse_compat(map, pin_fd)) { + pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n", + map->pin_path); + close(pin_fd); + return -EINVAL; + } + + err = bpf_map__reuse_fd(map, pin_fd); + if (err) { + close(pin_fd); + return err; + } + map->pinned = true; + pr_debug("reused pinned map at '%s'\n", map->pin_path); + + return 0; +} + static int bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) { @@ -2163,6 +2280,15 @@ bpf_object__create_maps(struct bpf_object *obj) char *cp, errmsg[STRERR_BUFSIZE]; int *pfd = &map->fd; + if (map->pin_path) { + err = bpf_object__reuse_map(map); + if (err) { + pr_warn("error reusing pinned map %s\n", + map->name); + return err; + } + } + if (map->fd >= 0) { pr_debug("skip map create (preset) %s: fd=%d\n", map->name, map->fd); @@ -2241,6 +2367,15 @@ err_out: } } + if (map->pin_path && !map->pinned) { + err = bpf_map__pin(map, NULL); + if (err) { + pr_warn("failed to auto-pin map name '%s' at '%s'\n", + map->name, map->pin_path); + return err; + } + } + pr_debug("created map %s: fd=%d\n", map->name, *pfd); } @@ -3615,6 +3750,7 @@ static struct bpf_object * __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, struct bpf_object_open_opts *opts) { + const char *pin_root_path; struct bpf_program *prog; struct bpf_object *obj; const char *obj_name; @@ -3649,11 +3785,13 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz, obj->relaxed_core_relocs = OPTS_GET(opts, relaxed_core_relocs, false); relaxed_maps = OPTS_GET(opts, relaxed_maps, false); + pin_root_path = OPTS_GET(opts, pin_root_path, NULL); CHECK_ERR(bpf_object__elf_init(obj), err, out); CHECK_ERR(bpf_object__check_endianness(obj), err, out); CHECK_ERR(bpf_object__probe_caps(obj), err, out); - CHECK_ERR(bpf_object__elf_collect(obj, relaxed_maps), err, out); + CHECK_ERR(bpf_object__elf_collect(obj, relaxed_maps, pin_root_path), + err, out); CHECK_ERR(bpf_object__collect_reloc(obj), err, out); bpf_object__elf_finish(obj); @@ -3808,6 +3946,28 @@ int bpf_object__load(struct bpf_object *obj) return bpf_object__load_xattr(&attr); } +static int make_parent_dir(const char *path) +{ + char *cp, errmsg[STRERR_BUFSIZE]; + char *dname, *dir; + int err = 0; + + dname = strdup(path); + if (dname == NULL) + return -ENOMEM; + + dir = dirname(dname); + if (mkdir(dir, 0700) && errno != EEXIST) + err = -errno; + + free(dname); + if (err) { + cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warn("failed to mkdir %s: %s\n", path, cp); + } + return err; +} + static int check_path(const char *path) { char *cp, errmsg[STRERR_BUFSIZE]; @@ -3844,6 +4004,10 @@ int bpf_program__pin_instance(struct bpf_program *prog, const char *path, char *cp, errmsg[STRERR_BUFSIZE]; int err; + err = make_parent_dir(path); + if (err) + return err; + err = check_path(path); if (err) return err; @@ -3897,25 +4061,14 @@ int bpf_program__unpin_instance(struct bpf_program *prog, const char *path, return 0; } -static int make_dir(const char *path) -{ - char *cp, errmsg[STRERR_BUFSIZE]; - int err = 0; - - if (mkdir(path, 0700) && errno != EEXIST) - err = -errno; - - if (err) { - cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); - pr_warn("failed to mkdir %s: %s\n", path, cp); - } - return err; -} - int bpf_program__pin(struct bpf_program *prog, const char *path) { int i, err; + err = make_parent_dir(path); + if (err) + return err; + err = check_path(path); if (err) return err; @@ -3936,10 +4089,6 @@ int bpf_program__pin(struct bpf_program *prog, const char *path) return bpf_program__pin_instance(prog, path, 0); } - err = make_dir(path); - if (err) - return err; - for (i = 0; i < prog->instances.nr; i++) { char buf[PATH_MAX]; int len; @@ -4030,47 +4179,123 @@ int bpf_map__pin(struct bpf_map *map, const char *path) char *cp, errmsg[STRERR_BUFSIZE]; int err; - err = check_path(path); - if (err) - return err; - if (map == NULL) { pr_warn("invalid map pointer\n"); return -EINVAL; } - if (bpf_obj_pin(map->fd, path)) { - cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); - pr_warn("failed to pin map: %s\n", cp); - return -errno; + if (map->pin_path) { + if (path && strcmp(path, map->pin_path)) { + pr_warn("map '%s' already has pin path '%s' different from '%s'\n", + bpf_map__name(map), map->pin_path, path); + return -EINVAL; + } else if (map->pinned) { + pr_debug("map '%s' already pinned at '%s'; not re-pinning\n", + bpf_map__name(map), map->pin_path); + return 0; + } + } else { + if (!path) { + pr_warn("missing a path to pin map '%s' at\n", + bpf_map__name(map)); + return -EINVAL; + } else if (map->pinned) { + pr_warn("map '%s' already pinned\n", bpf_map__name(map)); + return -EEXIST; + } + + map->pin_path = strdup(path); + if (!map->pin_path) { + err = -errno; + goto out_err; + } + } + + err = make_parent_dir(map->pin_path); + if (err) + return err; + + err = check_path(map->pin_path); + if (err) + return err; + + if (bpf_obj_pin(map->fd, map->pin_path)) { + err = -errno; + goto out_err; } - pr_debug("pinned map '%s'\n", path); + map->pinned = true; + pr_debug("pinned map '%s'\n", map->pin_path); return 0; + +out_err: + cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg)); + pr_warn("failed to pin map: %s\n", cp); + return err; } int bpf_map__unpin(struct bpf_map *map, const char *path) { int err; - err = check_path(path); - if (err) - return err; - if (map == NULL) { pr_warn("invalid map pointer\n"); return -EINVAL; } + if (map->pin_path) { + if (path && strcmp(path, map->pin_path)) { + pr_warn("map '%s' already has pin path '%s' different from '%s'\n", + bpf_map__name(map), map->pin_path, path); + return -EINVAL; + } + path = map->pin_path; + } else if (!path) { + pr_warn("no path to unpin map '%s' from\n", + bpf_map__name(map)); + return -EINVAL; + } + + err = check_path(path); + if (err) + return err; + err = unlink(path); if (err != 0) return -errno; - pr_debug("unpinned map '%s'\n", path); + + map->pinned = false; + pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path); return 0; } +int bpf_map__set_pin_path(struct bpf_map *map, const char *path) +{ + char *new = NULL; + + if (path) { + new = strdup(path); + if (!new) + return -errno; + } + + free(map->pin_path); + map->pin_path = new; + return 0; +} + +const char *bpf_map__get_pin_path(const struct bpf_map *map) +{ + return map->pin_path; +} + +bool bpf_map__is_pinned(const struct bpf_map *map) +{ + return map->pinned; +} + int bpf_object__pin_maps(struct bpf_object *obj, const char *path) { struct bpf_map *map; @@ -4084,25 +4309,28 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path) return -ENOENT; } - err = make_dir(path); - if (err) - return err; - bpf_object__for_each_map(map, obj) { + char *pin_path = NULL; char buf[PATH_MAX]; - int len; - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) { - err = -EINVAL; - goto err_unpin_maps; - } else if (len >= PATH_MAX) { - err = -ENAMETOOLONG; - goto err_unpin_maps; + if (path) { + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + bpf_map__name(map)); + if (len < 0) { + err = -EINVAL; + goto err_unpin_maps; + } else if (len >= PATH_MAX) { + err = -ENAMETOOLONG; + goto err_unpin_maps; + } + pin_path = buf; + } else if (!map->pin_path) { + continue; } - err = bpf_map__pin(map, buf); + err = bpf_map__pin(map, pin_path); if (err) goto err_unpin_maps; } @@ -4111,17 +4339,10 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path) err_unpin_maps: while ((map = bpf_map__prev(map, obj))) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) - continue; - else if (len >= PATH_MAX) + if (!map->pin_path) continue; - bpf_map__unpin(map, buf); + bpf_map__unpin(map, NULL); } return err; @@ -4136,17 +4357,24 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) return -ENOENT; bpf_object__for_each_map(map, obj) { + char *pin_path = NULL; char buf[PATH_MAX]; - int len; - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) - return -EINVAL; - else if (len >= PATH_MAX) - return -ENAMETOOLONG; + if (path) { + int len; + + len = snprintf(buf, PATH_MAX, "%s/%s", path, + bpf_map__name(map)); + if (len < 0) + return -EINVAL; + else if (len >= PATH_MAX) + return -ENAMETOOLONG; + pin_path = buf; + } else if (!map->pin_path) { + continue; + } - err = bpf_map__unpin(map, buf); + err = bpf_map__unpin(map, pin_path); if (err) return err; } @@ -4167,10 +4395,6 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path) return -ENOENT; } - err = make_dir(path); - if (err) - return err; - bpf_object__for_each_program(prog, obj) { char buf[PATH_MAX]; int len; @@ -4271,6 +4495,7 @@ void bpf_object__close(struct bpf_object *obj) for (i = 0; i < obj->nr_maps; i++) { zfree(&obj->maps[i].name); + zfree(&obj->maps[i].pin_path); if (obj->maps[i].clear_priv) obj->maps[i].clear_priv(&obj->maps[i], obj->maps[i].priv); |