Commit 606274c5 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller

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: default avatarBrendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d390238c
...@@ -357,6 +357,13 @@ enum bpf_func_id { ...@@ -357,6 +357,13 @@ enum bpf_func_id {
*/ */
BPF_FUNC_get_hash_recalc, 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, __BPF_FUNC_MAX_ID,
}; };
......
...@@ -312,6 +312,17 @@ const struct bpf_func_proto *bpf_get_event_output_proto(void) ...@@ -312,6 +312,17 @@ const struct bpf_func_proto *bpf_get_event_output_proto(void)
return &bpf_event_output_proto; return &bpf_event_output_proto;
} }
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) static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
{ {
switch (func_id) { switch (func_id) {
...@@ -329,6 +340,8 @@ static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id) ...@@ -329,6 +340,8 @@ static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
return &bpf_tail_call_proto; return &bpf_tail_call_proto;
case BPF_FUNC_get_current_pid_tgid: case BPF_FUNC_get_current_pid_tgid:
return &bpf_get_current_pid_tgid_proto; 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: case BPF_FUNC_get_current_uid_gid:
return &bpf_get_current_uid_gid_proto; return &bpf_get_current_uid_gid_proto;
case BPF_FUNC_get_current_comm: case BPF_FUNC_get_current_comm:
......
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