1  // SPDX-License-Identifier: GPL-2.0
2  /* Copyright (C) 2022. Huawei Technologies Co., Ltd */
3  #include <linux/bpf.h>
4  #include <bpf/bpf_helpers.h>
5  #include <bpf/bpf_tracing.h>
6  
7  char _license[] SEC("license") = "GPL";
8  
9  struct {
10  	__uint(type, BPF_MAP_TYPE_HASH);
11  	__uint(max_entries, 1);
12  	__uint(key_size, sizeof(__u32));
13  	__uint(value_size, sizeof(__u32));
14  } htab SEC(".maps");
15  
16  int pid = 0;
17  int update_err = 0;
18  
19  SEC("?fentry/lookup_elem_raw")
lookup_elem_raw(void * ctx)20  int lookup_elem_raw(void *ctx)
21  {
22  	__u32 key = 0, value = 1;
23  
24  	if ((bpf_get_current_pid_tgid() >> 32) != pid)
25  		return 0;
26  
27  	update_err = bpf_map_update_elem(&htab, &key, &value, 0);
28  	return 0;
29  }
30