diff options
| author | Alexei Starovoitov <ast@fb.com> | 2016-07-06 22:38:36 -0700 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:50:27 +0300 |
| commit | c80f66cc54b24c560703b97ffbc289b524b29159 (patch) | |
| tree | d9b0cf5c9cffcd41de59911ed62bb7cb52419996 | |
| parent | 8dbaaca1649bf054d16c3b63107ce28c493cc2f7 (diff) | |
bpf: introduce bpf_get_current_task() helper
over time there were multiple requests to access different data
structures and fields of task_struct current, so finally add
the helper to access 'current' as-is. Tracing bpf programs will do
the rest of walking the pointers via bpf_probe_read().
Note that current can be null and bpf program has to deal it with,
but even dumb passing null into bpf_probe_read() is still safe.
Suggested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
| -rw-r--r-- | include/uapi/linux/bpf.h | 7 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 13 |
2 files changed, 20 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index f18995d0b8ff..626f03d35086 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -358,6 +358,13 @@ enum bpf_func_id { */ BPF_FUNC_get_hash_recalc, + /** + * u64 bpf_get_current_task(void) + * Returns current task_struct + * Return: current + */ + BPF_FUNC_get_current_task, + __BPF_FUNC_MAX_ID, }; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index be358b81a2c4..ed5d8fc09839 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -309,6 +309,17 @@ u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, return __bpf_perf_event_output(regs, map, flags, &raw); } +static u64 bpf_get_current_task(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + return (long) current; +} + +static const struct bpf_func_proto bpf_get_current_task_proto = { + .func = bpf_get_current_task, + .gpl_only = true, + .ret_type = RET_INTEGER, +}; + static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) { switch (func_id) { @@ -326,6 +337,8 @@ static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) return &bpf_tail_call_proto; case BPF_FUNC_get_current_pid_tgid: return &bpf_get_current_pid_tgid_proto; + case BPF_FUNC_get_current_task: + return &bpf_get_current_task_proto; case BPF_FUNC_get_current_uid_gid: return &bpf_get_current_uid_gid_proto; case BPF_FUNC_get_current_comm: |