1 // SPDX-License-Identifier: GPL-2.0-only
2
3 #include <linux/bpf.h>
4 #include <bpf/bpf_helpers.h>
5
6 struct inner_map {
7 __uint(type, BPF_MAP_TYPE_ARRAY);
8 __uint(max_entries, 5);
9 __type(key, int);
10 __type(value, int);
11 } inner_map1 SEC(".maps");
12
13 struct outer_map {
14 __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
15 __uint(max_entries, 3);
16 __type(key, int);
17 __array(values, struct inner_map);
18 } outer_map1 SEC(".maps") = {
19 .values = {
20 [2] = &inner_map1,
21 },
22 };
23
24 SEC("raw_tp/sys_enter")
handle__sys_enter(void * ctx)25 int handle__sys_enter(void *ctx)
26 {
27 int outer_key = 2, inner_key = 3;
28 int *val;
29 void *map;
30
31 map = bpf_map_lookup_elem(&outer_map1, &outer_key);
32 if (!map)
33 return 1;
34
35 val = bpf_map_lookup_elem(map, &inner_key);
36 if (!val)
37 return 1;
38
39 if (*val == 1)
40 *val = 2;
41
42 return 0;
43 }
44
45 char _license[] SEC("license") = "GPL";
46