From: Andrii Nakryiko andriin@fb.com
[ Upstream commit 2d39d7c56f115148b05d1d8c6b8698a5730c8b53 ]
Factor out map creation and destruction logic to simplify code and especially error handling. Also fix map FD leak in case of partially successful map creation during bpf_object load operation.
Fixes: 57a00f41644f ("libbpf: Add auto-pinning of maps when loading BPF objects") Signed-off-by: Andrii Nakryiko andriin@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Toke Høiland-Jørgensen toke@redhat.com Link: https://lore.kernel.org/bpf/20200429002739.48006-3-andriin@fb.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 226 ++++++++++++++++++++++------------------- 1 file changed, 121 insertions(+), 105 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 8f480e29a6b0..63fc872723fc 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3482,107 +3482,111 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) return 0; }
+static void bpf_map__destroy(struct bpf_map *map); + +static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) +{ + struct bpf_create_map_attr create_attr; + struct bpf_map_def *def = &map->def; + + memset(&create_attr, 0, sizeof(create_attr)); + + if (obj->caps.name) + create_attr.name = map->name; + create_attr.map_ifindex = map->map_ifindex; + create_attr.map_type = def->type; + create_attr.map_flags = def->map_flags; + create_attr.key_size = def->key_size; + create_attr.value_size = def->value_size; + + if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) { + int nr_cpus; + + nr_cpus = libbpf_num_possible_cpus(); + if (nr_cpus < 0) { + pr_warn("map '%s': failed to determine number of system CPUs: %d\n", + map->name, nr_cpus); + return nr_cpus; + } + pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus); + create_attr.max_entries = nr_cpus; + } else { + create_attr.max_entries = def->max_entries; + } + + if (bpf_map__is_struct_ops(map)) + create_attr.btf_vmlinux_value_type_id = + map->btf_vmlinux_value_type_id; + + create_attr.btf_fd = 0; + create_attr.btf_key_type_id = 0; + create_attr.btf_value_type_id = 0; + if (obj->btf && !bpf_map_find_btf_info(obj, map)) { + create_attr.btf_fd = btf__fd(obj->btf); + create_attr.btf_key_type_id = map->btf_key_type_id; + create_attr.btf_value_type_id = map->btf_value_type_id; + } + + map->fd = bpf_create_map_xattr(&create_attr); + if (map->fd < 0 && (create_attr.btf_key_type_id || + create_attr.btf_value_type_id)) { + char *cp, errmsg[STRERR_BUFSIZE]; + int err = -errno; + + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", + map->name, cp, err); + create_attr.btf_fd = 0; + create_attr.btf_key_type_id = 0; + create_attr.btf_value_type_id = 0; + map->btf_key_type_id = 0; + map->btf_value_type_id = 0; + map->fd = bpf_create_map_xattr(&create_attr); + } + + if (map->fd < 0) + return -errno; + + return 0; +} + static int bpf_object__create_maps(struct bpf_object *obj) { - struct bpf_create_map_attr create_attr = {}; - int nr_cpus = 0; - unsigned int i; + struct bpf_map *map; + char *cp, errmsg[STRERR_BUFSIZE]; + unsigned int i, j; int err;
for (i = 0; i < obj->nr_maps; i++) { - struct bpf_map *map = &obj->maps[i]; - struct bpf_map_def *def = &map->def; - char *cp, errmsg[STRERR_BUFSIZE]; - int *pfd = &map->fd; + map = &obj->maps[i];
if (map->pin_path) { err = bpf_object__reuse_map(map); if (err) { - pr_warn("error reusing pinned map %s\n", + pr_warn("map '%s': error reusing pinned map\n", map->name); - return err; + goto err_out; } }
if (map->fd >= 0) { - pr_debug("skip map create (preset) %s: fd=%d\n", + pr_debug("map '%s': skipping creation (preset fd=%d)\n", map->name, map->fd); continue; }
- if (obj->caps.name) - create_attr.name = map->name; - create_attr.map_ifindex = map->map_ifindex; - create_attr.map_type = def->type; - create_attr.map_flags = def->map_flags; - create_attr.key_size = def->key_size; - create_attr.value_size = def->value_size; - if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && - !def->max_entries) { - if (!nr_cpus) - nr_cpus = libbpf_num_possible_cpus(); - if (nr_cpus < 0) { - pr_warn("failed to determine number of system CPUs: %d\n", - nr_cpus); - err = nr_cpus; - goto err_out; - } - pr_debug("map '%s': setting size to %d\n", - map->name, nr_cpus); - create_attr.max_entries = nr_cpus; - } else { - create_attr.max_entries = def->max_entries; - } - create_attr.btf_fd = 0; - create_attr.btf_key_type_id = 0; - create_attr.btf_value_type_id = 0; - if (bpf_map_type__is_map_in_map(def->type) && - map->inner_map_fd >= 0) - create_attr.inner_map_fd = map->inner_map_fd; - if (bpf_map__is_struct_ops(map)) - create_attr.btf_vmlinux_value_type_id = - map->btf_vmlinux_value_type_id; - - if (obj->btf && !bpf_map_find_btf_info(obj, map)) { - create_attr.btf_fd = btf__fd(obj->btf); - create_attr.btf_key_type_id = map->btf_key_type_id; - create_attr.btf_value_type_id = map->btf_value_type_id; - } - - *pfd = bpf_create_map_xattr(&create_attr); - if (*pfd < 0 && (create_attr.btf_key_type_id || - create_attr.btf_value_type_id)) { - err = -errno; - cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); - pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n", - map->name, cp, err); - create_attr.btf_fd = 0; - create_attr.btf_key_type_id = 0; - create_attr.btf_value_type_id = 0; - map->btf_key_type_id = 0; - map->btf_value_type_id = 0; - *pfd = bpf_create_map_xattr(&create_attr); - } - - if (*pfd < 0) { - size_t j; + err = bpf_object__create_map(obj, map); + if (err) + goto err_out;
- err = -errno; -err_out: - cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); - pr_warn("failed to create map (name: '%s'): %s(%d)\n", - map->name, cp, err); - pr_perm_msg(err); - for (j = 0; j < i; j++) - zclose(obj->maps[j].fd); - return err; - } + pr_debug("map '%s': created successfully, fd=%d\n", map->name, + map->fd);
if (bpf_map__is_internal(map)) { err = bpf_object__populate_internal_map(obj, map); if (err < 0) { - zclose(*pfd); + zclose(map->fd); goto err_out; } } @@ -3590,16 +3594,23 @@ bpf_object__create_maps(struct bpf_object *obj) 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_warn("map '%s': failed to auto-pin at '%s': %d\n", + map->name, map->pin_path, err); + zclose(map->fd); + goto err_out; } } - - pr_debug("created map %s: fd=%d\n", map->name, *pfd); }
return 0; + +err_out: + cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg)); + pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err); + pr_perm_msg(err); + for (j = 0; j < i; j++) + zclose(obj->maps[j].fd); + return err; }
static int @@ -5955,6 +5966,32 @@ int bpf_object__pin(struct bpf_object *obj, const char *path) return 0; }
+static void bpf_map__destroy(struct bpf_map *map) +{ + if (map->clear_priv) + map->clear_priv(map, map->priv); + map->priv = NULL; + map->clear_priv = NULL; + + if (map->mmaped) { + munmap(map->mmaped, bpf_map_mmap_sz(map)); + map->mmaped = NULL; + } + + if (map->st_ops) { + zfree(&map->st_ops->data); + zfree(&map->st_ops->progs); + zfree(&map->st_ops->kern_func_off); + zfree(&map->st_ops); + } + + zfree(&map->name); + zfree(&map->pin_path); + + if (map->fd >= 0) + zclose(map->fd); +} + void bpf_object__close(struct bpf_object *obj) { size_t i; @@ -5970,29 +6007,8 @@ void bpf_object__close(struct bpf_object *obj) btf__free(obj->btf); btf_ext__free(obj->btf_ext);
- for (i = 0; i < obj->nr_maps; i++) { - struct bpf_map *map = &obj->maps[i]; - - if (map->clear_priv) - map->clear_priv(map, map->priv); - map->priv = NULL; - map->clear_priv = NULL; - - if (map->mmaped) { - munmap(map->mmaped, bpf_map_mmap_sz(map)); - map->mmaped = NULL; - } - - if (map->st_ops) { - zfree(&map->st_ops->data); - zfree(&map->st_ops->progs); - zfree(&map->st_ops->kern_func_off); - zfree(&map->st_ops); - } - - zfree(&map->name); - zfree(&map->pin_path); - } + for (i = 0; i < obj->nr_maps; i++) + bpf_map__destroy(&obj->maps[i]);
zfree(&obj->kconfig); zfree(&obj->externs);