bpf: introduce cgroup storage maps

This commit introduces BPF_MAP_TYPE_CGROUP_STORAGE maps:
a special type of maps which are implementing the cgroup storage.

>From the userspace point of view it's almost a generic
hash map with the (cgroup inode id, attachment type) pair
used as a key.

The only difference is that some operations are restricted:
  1) a user can't create new entries,
  2) a user can't remove existing entries.

The lookup from userspace is o(log(n)).

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Roman Gushchin
2018-08-02 14:27:18 -07:00
committed by Daniel Borkmann
parent 0a4c58f570
commit de9cbbaadb
8 changed files with 440 additions and 0 deletions

View File

@ -5154,6 +5154,14 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
}
env->used_maps[env->used_map_cnt++] = map;
if (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE &&
bpf_cgroup_storage_assign(env->prog, map)) {
verbose(env,
"only one cgroup storage is allowed\n");
fdput(f);
return -EBUSY;
}
fdput(f);
next_insn:
insn++;
@ -5180,6 +5188,10 @@ static void release_maps(struct bpf_verifier_env *env)
{
int i;
if (env->prog->aux->cgroup_storage)
bpf_cgroup_storage_release(env->prog,
env->prog->aux->cgroup_storage);
for (i = 0; i < env->used_map_cnt; i++)
bpf_map_put(env->used_maps[i]);
}