1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <vmlinux.h> |
3 | #include <bpf/bpf_tracing.h> |
4 | #include <bpf/bpf_helpers.h> |
5 | |
6 | struct map_value { |
7 | struct task_struct __kptr_untrusted *ptr; |
8 | }; |
9 | |
10 | struct { |
11 | __uint(type, BPF_MAP_TYPE_LRU_HASH); |
12 | __uint(max_entries, 1); |
13 | __type(key, int); |
14 | __type(value, struct map_value); |
15 | } lru_map SEC(".maps" ); |
16 | |
17 | int pid = 0; |
18 | int result = 1; |
19 | |
20 | SEC("fentry/bpf_ktime_get_ns" ) |
21 | int printk(void *ctx) |
22 | { |
23 | struct map_value v = {}; |
24 | |
25 | if (pid == bpf_get_current_task_btf()->pid) |
26 | bpf_map_update_elem(&lru_map, &(int){0}, &v, 0); |
27 | return 0; |
28 | } |
29 | |
30 | SEC("fentry/do_nanosleep" ) |
31 | int nanosleep(void *ctx) |
32 | { |
33 | struct map_value val = {}, *v; |
34 | struct task_struct *current; |
35 | |
36 | bpf_map_update_elem(&lru_map, &(int){0}, &val, 0); |
37 | v = bpf_map_lookup_elem(&lru_map, &(int){0}); |
38 | if (!v) |
39 | return 0; |
40 | bpf_map_delete_elem(&lru_map, &(int){0}); |
41 | current = bpf_get_current_task_btf(); |
42 | v->ptr = current; |
43 | pid = current->pid; |
44 | bpf_ktime_get_ns(); |
45 | result = !v->ptr; |
46 | return 0; |
47 | } |
48 | |
49 | char _license[] SEC("license" ) = "GPL" ; |
50 | |