test_send_signal_kern.c

 1// SPDX-License-Identifier: GPL-2.0
 2// Copyright (c) 2019 Facebook
 3#include <vmlinux.h>
 4#include <linux/version.h>
 5#include <bpf/bpf_helpers.h>
 6
 7struct task_struct *bpf_task_from_pid(int pid) __ksym;
 8void bpf_task_release(struct task_struct *p) __ksym;
 9int bpf_send_signal_task(struct task_struct *task, int sig, enum pid_type type, u64 value) __ksym;
10
11__u32 sig = 0, pid = 0, status = 0, signal_thread = 0, target_pid = 0;
12
13static __always_inline int bpf_send_signal_test(void *ctx)
14{
15	struct task_struct *target_task = NULL;
16	int ret;
17	u64 value;
18
19	if (status != 0 || pid == 0)
20		return 0;
21
22	if ((bpf_get_current_pid_tgid() >> 32) == pid) {
23		if (target_pid) {
24			target_task = bpf_task_from_pid(target_pid);
25			if (!target_task)
26				return 0;
27			value = 8;
28		}
29
30		if (signal_thread) {
31			if (target_pid)
32				ret = bpf_send_signal_task(target_task, sig, PIDTYPE_PID, value);
33			else
34				ret = bpf_send_signal_thread(sig);
35		} else {
36			if (target_pid)
37				ret = bpf_send_signal_task(target_task, sig, PIDTYPE_TGID, value);
38			else
39				ret = bpf_send_signal(sig);
40		}
41		if (ret == 0)
42			status = 1;
43	}
44
45	if (target_task)
46		bpf_task_release(target_task);
47
48	return 0;
49}
50
51SEC("tracepoint/syscalls/sys_enter_nanosleep")
52int send_signal_tp(void *ctx)
53{
54	return bpf_send_signal_test(ctx);
55}
56
57SEC("tracepoint/sched/sched_switch")
58int send_signal_tp_sched(void *ctx)
59{
60	return bpf_send_signal_test(ctx);
61}
62
63SEC("perf_event")
64int send_signal_perf(void *ctx)
65{
66	return bpf_send_signal_test(ctx);
67}
68
69char __license[] SEC("license") = "GPL";