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- // SPDX-License-Identifier: GPL-2.0-only
- /* Copyright (c) 2017 Facebook
- */
- #include <linux/slab.h>
- #include <linux/bpf.h>
- #include <linux/btf.h>
- #include "map_in_map.h"
- struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
- {
- struct bpf_map *inner_map, *inner_map_meta;
- u32 inner_map_meta_size;
- struct fd f;
- f = fdget(inner_map_ufd);
- inner_map = __bpf_map_get(f);
- if (IS_ERR(inner_map))
- return inner_map;
- /* Does not support >1 level map-in-map */
- if (inner_map->inner_map_meta) {
- fdput(f);
- return ERR_PTR(-EINVAL);
- }
- if (!inner_map->ops->map_meta_equal) {
- fdput(f);
- return ERR_PTR(-ENOTSUPP);
- }
- if (map_value_has_spin_lock(inner_map)) {
- fdput(f);
- return ERR_PTR(-ENOTSUPP);
- }
- inner_map_meta_size = sizeof(*inner_map_meta);
- /* In some cases verifier needs to access beyond just base map. */
- if (inner_map->ops == &array_map_ops)
- inner_map_meta_size = sizeof(struct bpf_array);
- inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
- if (!inner_map_meta) {
- fdput(f);
- return ERR_PTR(-ENOMEM);
- }
- inner_map_meta->map_type = inner_map->map_type;
- inner_map_meta->key_size = inner_map->key_size;
- inner_map_meta->value_size = inner_map->value_size;
- inner_map_meta->map_flags = inner_map->map_flags;
- inner_map_meta->max_entries = inner_map->max_entries;
- inner_map_meta->spin_lock_off = inner_map->spin_lock_off;
- inner_map_meta->timer_off = inner_map->timer_off;
- inner_map_meta->kptr_off_tab = bpf_map_copy_kptr_off_tab(inner_map);
- if (inner_map->btf) {
- btf_get(inner_map->btf);
- inner_map_meta->btf = inner_map->btf;
- }
- /* Misc members not needed in bpf_map_meta_equal() check. */
- inner_map_meta->ops = inner_map->ops;
- if (inner_map->ops == &array_map_ops) {
- struct bpf_array *inner_array_meta =
- container_of(inner_map_meta, struct bpf_array, map);
- struct bpf_array *inner_array = container_of(inner_map, struct bpf_array, map);
- inner_array_meta->index_mask = inner_array->index_mask;
- inner_array_meta->elem_size = inner_array->elem_size;
- inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1;
- }
- fdput(f);
- return inner_map_meta;
- }
- void bpf_map_meta_free(struct bpf_map *map_meta)
- {
- bpf_map_free_kptr_off_tab(map_meta);
- btf_put(map_meta->btf);
- kfree(map_meta);
- }
- bool bpf_map_meta_equal(const struct bpf_map *meta0,
- const struct bpf_map *meta1)
- {
- /* No need to compare ops because it is covered by map_type */
- return meta0->map_type == meta1->map_type &&
- meta0->key_size == meta1->key_size &&
- meta0->value_size == meta1->value_size &&
- meta0->timer_off == meta1->timer_off &&
- meta0->map_flags == meta1->map_flags &&
- bpf_map_equal_kptr_off_tab(meta0, meta1);
- }
- void *bpf_map_fd_get_ptr(struct bpf_map *map,
- struct file *map_file /* not used */,
- int ufd)
- {
- struct bpf_map *inner_map, *inner_map_meta;
- struct fd f;
- f = fdget(ufd);
- inner_map = __bpf_map_get(f);
- if (IS_ERR(inner_map))
- return inner_map;
- inner_map_meta = map->inner_map_meta;
- if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map))
- bpf_map_inc(inner_map);
- else
- inner_map = ERR_PTR(-EINVAL);
- fdput(f);
- return inner_map;
- }
- void bpf_map_fd_put_ptr(void *ptr)
- {
- /* ptr->ops->map_free() has to go through one
- * rcu grace period by itself.
- */
- bpf_map_put(ptr);
- }
- u32 bpf_map_fd_sys_lookup_elem(void *ptr)
- {
- return ((struct bpf_map *)ptr)->id;
- }
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