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authorAlexei Starovoitov <ast@fb.com>2016-07-06 22:38:36 -0700
committerDavid S. Miller <davem@davemloft.net>2016-07-09 00:00:16 -0400
commit606274c5abd8e245add01bc7145a8cbb92b69ba8 (patch)
tree762718058c0cf327284f07fa6c1eb2410ee3e0b7 /kernel/trace
parentd390238c4fba7c87a3bcd859ce3373c864eb7b02 (diff)
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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>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/bpf_trace.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 19c5b4a5c3eb..094c716154ed 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -312,6 +312,17 @@ const struct bpf_func_proto *bpf_get_event_output_proto(void)
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)
{
switch (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;
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: