1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */ 3 4 #include "vmlinux.h" 5 #include <bpf/bpf_helpers.h> 6 7 #include "bpf_misc.h" 8 9 char _license[] SEC("license") = "GPL"; 10 11 struct inner_array_type { 12 __uint(type, BPF_MAP_TYPE_ARRAY); 13 __uint(map_flags, BPF_F_MMAPABLE); 14 __type(key, __u32); 15 __type(value, __u64); 16 __uint(max_entries, 1); 17 } inner_array SEC(".maps"); 18 19 struct { 20 __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS); 21 __uint(key_size, 4); 22 __uint(value_size, 4); 23 __uint(max_entries, 1); 24 __array(values, struct inner_array_type); 25 } outer_map SEC(".maps"); 26 27 int pid = 0; 28 __u64 match_value = 0x13572468; 29 bool done = false; 30 bool pid_match = false; 31 bool outer_map_match = false; 32 33 SEC("fentry/" SYS_PREFIX "sys_nanosleep") 34 int add_to_list_in_inner_array(void *ctx) 35 { 36 __u32 curr_pid, zero = 0; 37 struct bpf_map *map; 38 __u64 *value; 39 40 curr_pid = (u32)bpf_get_current_pid_tgid(); 41 if (done || curr_pid != pid) 42 return 0; 43 44 pid_match = true; 45 map = bpf_map_lookup_elem(&outer_map, &curr_pid); 46 if (!map) 47 return 0; 48 49 outer_map_match = true; 50 value = bpf_map_lookup_elem(map, &zero); 51 if (!value) 52 return 0; 53 54 *value = match_value; 55 done = true; 56 return 0; 57 } 58