1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) 2023. Huawei Technologies Co., Ltd */
3#include <vmlinux.h>
4#include <bpf/bpf_tracing.h>
5#include <bpf/bpf_helpers.h>
6
7#include "bpf_misc.h"
8#include "bpf_experimental.h"
9
10struct node_data {
11	__u64 data;
12	struct bpf_list_node node;
13};
14
15struct map_value {
16	struct bpf_list_head head __contains(node_data, node);
17	struct bpf_spin_lock lock;
18};
19
20struct inner_array_type {
21	__uint(type, BPF_MAP_TYPE_ARRAY);
22	__type(key, int);
23	__type(value, struct map_value);
24	__uint(max_entries, 1);
25} inner_array SEC(".maps");
26
27struct {
28	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
29	__uint(key_size, 4);
30	__uint(value_size, 4);
31	__uint(max_entries, 1);
32	__array(values, struct inner_array_type);
33} outer_array SEC(".maps") = {
34	.values = {
35		[0] = &inner_array,
36	},
37};
38
39char _license[] SEC("license") = "GPL";
40
41int pid = 0;
42bool done = false;
43
44SEC("fentry/" SYS_PREFIX "sys_nanosleep")
45int add_to_list_in_inner_array(void *ctx)
46{
47	struct map_value *value;
48	struct node_data *new;
49	struct bpf_map *map;
50	int zero = 0;
51
52	if (done || (u32)bpf_get_current_pid_tgid() != pid)
53		return 0;
54
55	map = bpf_map_lookup_elem(&outer_array, &zero);
56	if (!map)
57		return 0;
58
59	value = bpf_map_lookup_elem(map, &zero);
60	if (!value)
61		return 0;
62
63	new = bpf_obj_new(typeof(*new));
64	if (!new)
65		return 0;
66
67	bpf_spin_lock(&value->lock);
68	bpf_list_push_back(&value->head, &new->node);
69	bpf_spin_unlock(&value->lock);
70	done = true;
71
72	return 0;
73}
74