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 {
21	__uint(type, BPF_MAP_TYPE_ARRAY);
22	__type(key, int);
23	__type(value, struct map_value);
24	__uint(max_entries, 1);
25} array SEC(".maps");
26
27char _license[] SEC("license") = "GPL";
28
29int pid = 0;
30bool done = false;
31
32SEC("fentry/" SYS_PREFIX "sys_nanosleep")
33int add_to_list_in_array(void *ctx)
34{
35	struct map_value *value;
36	struct node_data *new;
37	int zero = 0;
38
39	if (done || (int)bpf_get_current_pid_tgid() != pid)
40		return 0;
41
42	value = bpf_map_lookup_elem(&array, &zero);
43	if (!value)
44		return 0;
45
46	new = bpf_obj_new(typeof(*new));
47	if (!new)
48		return 0;
49
50	bpf_spin_lock(&value->lock);
51	bpf_list_push_back(&value->head, &new->node);
52	bpf_spin_unlock(&value->lock);
53	done = true;
54
55	return 0;
56}
57