1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7
8/* modifiers and typedefs are ignored when comparing key/value types */
9typedef struct my_key { long x; } key_type;
10typedef struct my_value { long x; } value_type;
11
12extern struct {
13 __uint(max_entries, 16);
14 __type(key, key_type);
15 __type(value, value_type);
16 __uint(type, BPF_MAP_TYPE_HASH);
17} map1 SEC(".maps");
18
19struct {
20 __uint(type, BPF_MAP_TYPE_ARRAY);
21 __type(key, int);
22 __type(value, int);
23 __uint(max_entries, 8);
24} map2 SEC(".maps");
25
26/* this definition will lose, but it has to exactly match the winner */
27struct {
28 __uint(type, BPF_MAP_TYPE_ARRAY);
29 __type(key, int);
30 __type(value, int);
31 __uint(max_entries, 16);
32} map_weak __weak SEC(".maps");
33
34int output_first2;
35int output_second2;
36int output_weak2;
37
38SEC("raw_tp/sys_enter")
39int BPF_PROG(handler_enter2)
40{
41 /* update values with key = 2 */
42 int key = 2, val = 2;
43 key_type key_struct = { .x = 2 };
44 value_type val_struct = { .x = 2000 };
45
46 bpf_map_update_elem(&map1, &key_struct, &val_struct, 0);
47 bpf_map_update_elem(&map2, &key, &val, 0);
48 bpf_map_update_elem(&map_weak, &key, &val, 0);
49
50 return 0;
51}
52
53SEC("raw_tp/sys_exit")
54int BPF_PROG(handler_exit2)
55{
56 /* lookup values with key = 1, set in another file */
57 int key = 1, *val;
58 key_type key_struct = { .x = 1 };
59 value_type *value_struct;
60
61 value_struct = bpf_map_lookup_elem(&map1, &key_struct);
62 if (value_struct)
63 output_first2 = value_struct->x;
64
65 val = bpf_map_lookup_elem(&map2, &key);
66 if (val)
67 output_second2 = *val;
68
69 val = bpf_map_lookup_elem(&map_weak, &key);
70 if (val)
71 output_weak2 = *val;
72
73 return 0;
74}
75
76char LICENSE[] SEC("license") = "GPL";
77

source code of linux/tools/testing/selftests/bpf/progs/linked_maps2.c