perf augmented_syscalls: Filter on a hard coded pid
Just to show where we'll hook pid based filters, and what we use to
obtain the current pid, using a BPF getpid() equivalent.
Now we need to remove that hardcoded PID with a BPF hash map, so that we
start by filtering 'perf trace's own PID, implement the --filter-pid
functionality, etc.
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c
index 90a1933..2feb000 100644
--- a/tools/perf/examples/bpf/augmented_raw_syscalls.c
+++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c
@@ -15,6 +15,7 @@
*/
#include <stdio.h>
+#include <unistd.h>
#include <linux/socket.h>
/* bpf-output associated map */
@@ -56,6 +57,9 @@ int sys_enter(struct syscall_enter_args *args)
unsigned int len = sizeof(augmented_args);
const void *filename_arg = NULL;
+ if (getpid() == 2971)
+ return 0;
+
probe_read(&augmented_args.args, sizeof(augmented_args.args), args);
/*
* Yonghong and Edward Cree sayz:
@@ -125,7 +129,7 @@ int sys_enter(struct syscall_enter_args *args)
SEC("raw_syscalls:sys_exit")
int sys_exit(struct syscall_exit_args *args)
{
- return 1; /* 0 as soon as we start copying data returned by the kernel, e.g. 'read' */
+ return getpid() != 2971;
}
license(GPL);
