bpf: Add BPF_PROG_GET_FD_BY_ID
Add BPF_PROG_GET_FD_BY_ID command to allow user to get a fd
from a bpf_prog's ID.
bpf_prog_inc_not_zero() is added and is called with prog_idr_lock
held.
__bpf_prog_put() is also added which has the 'bool do_idr_lock'
param to decide if the prog_idr_lock should be acquired when
freeing the prog->id.
In the error path of bpf_prog_inc_not_zero(), it may have to
call __bpf_prog_put(map, false) which does not need
to take the prog_idr_lock when freeing the prog->id.
It is currently limited to CAP_SYS_ADMIN which we can
consider to lift it in followup patches.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 629747a..d70cfed 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -84,6 +84,7 @@ enum bpf_cmd {
BPF_PROG_TEST_RUN,
BPF_PROG_GET_NEXT_ID,
BPF_MAP_GET_NEXT_ID,
+ BPF_PROG_GET_FD_BY_ID,
};
enum bpf_map_type {
@@ -212,8 +213,11 @@ union bpf_attr {
__u32 duration;
} test;
- struct { /* anonymous struct used by BPF_*_GET_NEXT_ID */
- __u32 start_id;
+ struct { /* anonymous struct used by BPF_*_GET_*_ID */
+ union {
+ __u32 start_id;
+ __u32 prog_id;
+ };
__u32 next_id;
};
} __attribute__((aligned(8)));