1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
3 
4 #include "vmlinux.h"
5 #include <bpf/bpf_helpers.h>
6 
7 __u64 inKey = 0;
8 __u64 inValue = 0;
9 __u32 inPid = 0;
10 
11 struct {
12 	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
13 	__uint(max_entries, 2);
14 	__type(key, __u64);
15 	__type(value, __u64);
16 } hashmap1 SEC(".maps");
17 
18 
19 SEC("tp/syscalls/sys_enter_getpgid")
sysenter_getpgid(const void * ctx)20 int sysenter_getpgid(const void *ctx)
21 {
22 	/* Just do it for once, when called from our own test prog. This
23 	 * ensures the map value is only updated for a single CPU.
24 	 */
25 	int cur_pid = bpf_get_current_pid_tgid() >> 32;
26 
27 	if (cur_pid == inPid)
28 		bpf_map_update_elem(&hashmap1, &inKey, &inValue, BPF_NOEXIST);
29 
30 	return 0;
31 }
32 
33 char _license[] SEC("license") = "GPL";
34