From f08c18e083adfef92946ae1d44b07bb81e727e08 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 3 Jan 2024 17:38:41 -0800 Subject: libbpf: don't rely on map->fd as an indicator of map being created With the upcoming switch to preallocated placeholder FDs for maps, switch various getters/setter away from checking map->fd. Use map_is_created() helper that detect whether BPF map can be modified based on map->obj->loaded state, with special provision for maps set up with bpf_map__reuse_fd(). For backwards compatibility, we take map_is_created() into account in bpf_map__fd() getter as well. This way before bpf_object__load() phase bpf_map__fd() will always return -1, just as before the changes in subsequent patches adding stable map->fd placeholders. We also get rid of all internal uses of bpf_map__fd() getter, as it's more oriented for uses external to libbpf. The above map_is_created() check actually interferes with some of the internal uses, if map FD is fetched through bpf_map__fd(). Acked-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240104013847.3875810-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/libbpf.c | 42 +++++++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 15 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3b678b617213..6b27edd47c84 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5200,6 +5200,11 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map) static void bpf_map__destroy(struct bpf_map *map); +static bool map_is_created(const struct bpf_map *map) +{ + return map->obj->loaded || map->reused; +} + static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, bool is_inner) { LIBBPF_OPTS(bpf_map_create_opts, create_attr); @@ -5231,7 +5236,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b map->name, err); return err; } - map->inner_map_fd = bpf_map__fd(map->inner_map); + map->inner_map_fd = map->inner_map->fd; } if (map->inner_map_fd >= 0) create_attr.inner_map_fd = map->inner_map_fd; @@ -5314,7 +5319,7 @@ static int init_map_in_map_slots(struct bpf_object *obj, struct bpf_map *map) continue; targ_map = map->init_slots[i]; - fd = bpf_map__fd(targ_map); + fd = targ_map->fd; if (obj->gen_loader) { bpf_gen__populate_outer_map(obj->gen_loader, @@ -7135,7 +7140,7 @@ retry_load: if (map->libbpf_type != LIBBPF_MAP_RODATA) continue; - if (bpf_prog_bind_map(ret, bpf_map__fd(map), NULL)) { + if (bpf_prog_bind_map(ret, map->fd, NULL)) { cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg)); pr_warn("prog '%s': failed to bind map '%s': %s\n", prog->name, map->real_name, cp); @@ -9601,7 +9606,11 @@ int libbpf_attach_type_by_name(const char *name, int bpf_map__fd(const struct bpf_map *map) { - return map ? map->fd : libbpf_err(-EINVAL); + if (!map) + return libbpf_err(-EINVAL); + if (!map_is_created(map)) + return -1; + return map->fd; } static bool map_uses_real_name(const struct bpf_map *map) @@ -9637,7 +9646,7 @@ enum bpf_map_type bpf_map__type(const struct bpf_map *map) int bpf_map__set_type(struct bpf_map *map, enum bpf_map_type type) { - if (map->fd >= 0) + if (map_is_created(map)) return libbpf_err(-EBUSY); map->def.type = type; return 0; @@ -9650,7 +9659,7 @@ __u32 bpf_map__map_flags(const struct bpf_map *map) int bpf_map__set_map_flags(struct bpf_map *map, __u32 flags) { - if (map->fd >= 0) + if (map_is_created(map)) return libbpf_err(-EBUSY); map->def.map_flags = flags; return 0; @@ -9663,7 +9672,7 @@ __u64 bpf_map__map_extra(const struct bpf_map *map) int bpf_map__set_map_extra(struct bpf_map *map, __u64 map_extra) { - if (map->fd >= 0) + if (map_is_created(map)) return libbpf_err(-EBUSY); map->map_extra = map_extra; return 0; @@ -9676,7 +9685,7 @@ __u32 bpf_map__numa_node(const struct bpf_map *map) int bpf_map__set_numa_node(struct bpf_map *map, __u32 numa_node) { - if (map->fd >= 0) + if (map_is_created(map)) return libbpf_err(-EBUSY); map->numa_node = numa_node; return 0; @@ -9689,7 +9698,7 @@ __u32 bpf_map__key_size(const struct bpf_map *map) int bpf_map__set_key_size(struct bpf_map *map, __u32 size) { - if (map->fd >= 0) + if (map_is_created(map)) return libbpf_err(-EBUSY); map->def.key_size = size; return 0; @@ -9773,7 +9782,7 @@ static int map_btf_datasec_resize(struct bpf_map *map, __u32 size) int bpf_map__set_value_size(struct bpf_map *map, __u32 size) { - if (map->fd >= 0) + if (map->obj->loaded || map->reused) return libbpf_err(-EBUSY); if (map->mmaped) { @@ -9814,8 +9823,11 @@ __u32 bpf_map__btf_value_type_id(const struct bpf_map *map) int bpf_map__set_initial_value(struct bpf_map *map, const void *data, size_t size) { + if (map->obj->loaded || map->reused) + return libbpf_err(-EBUSY); + if (!map->mmaped || map->libbpf_type == LIBBPF_MAP_KCONFIG || - size != map->def.value_size || map->fd >= 0) + size != map->def.value_size) return libbpf_err(-EINVAL); memcpy(map->mmaped, data, size); @@ -9842,7 +9854,7 @@ __u32 bpf_map__ifindex(const struct bpf_map *map) int bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex) { - if (map->fd >= 0) + if (map_is_created(map)) return libbpf_err(-EBUSY); map->map_ifindex = ifindex; return 0; @@ -9947,7 +9959,7 @@ bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name) static int validate_map_op(const struct bpf_map *map, size_t key_sz, size_t value_sz, bool check_value_sz) { - if (map->fd <= 0) + if (!map_is_created(map)) /* map is not yet created */ return -ENOENT; if (map->def.key_size != key_sz) { @@ -12400,7 +12412,7 @@ int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *map) __u32 zero = 0; int err; - if (!bpf_map__is_struct_ops(map) || map->fd < 0) + if (!bpf_map__is_struct_ops(map) || !map_is_created(map)) return -EINVAL; st_ops_link = container_of(link, struct bpf_link_struct_ops, link); @@ -13304,7 +13316,7 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) for (i = 0; i < s->map_cnt; i++) { struct bpf_map *map = *s->maps[i].map; size_t mmap_sz = bpf_map_mmap_sz(map->def.value_size, map->def.max_entries); - int prot, map_fd = bpf_map__fd(map); + int prot, map_fd = map->fd; void **mmaped = s->maps[i].mmaped; if (!mmaped) -- cgit v1.2.3