1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Facebook
3 
4 #include <linux/ptrace.h>
5 #include <linux/bpf.h>
6 #include <bpf/bpf_helpers.h>
7 #include <bpf/bpf_tracing.h>
8 
9 struct {
10 	__uint(type, BPF_MAP_TYPE_ARRAY);
11 	__type(key, int);
12 	__type(value, int);
13 	__uint(max_entries, 1);
14 } my_pid_map SEC(".maps");
15 
16 struct {
17 	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
18 	__type(key, int);
19 	__type(value, int);
20 } perf_buf_map SEC(".maps");
21 
22 SEC("tp/raw_syscalls/sys_enter")
23 int handle_sys_enter(void *ctx)
24 {
25 	int zero = 0, *my_pid, cur_pid;
26 	int cpu = bpf_get_smp_processor_id();
27 
28 	my_pid = bpf_map_lookup_elem(&my_pid_map, &zero);
29 	if (!my_pid)
30 		return 1;
31 
32 	cur_pid = bpf_get_current_pid_tgid() >> 32;
33 	if (cur_pid != *my_pid)
34 		return 1;
35 
36 	bpf_perf_event_output(ctx, &perf_buf_map, BPF_F_CURRENT_CPU,
37 			      &cpu, sizeof(cpu));
38 	return 1;
39 }
40 
41 char _license[] SEC("license") = "GPL";
42