1// SPDX-License-Identifier: GPL-2.0
2/*
3 * User Events ABI Test Program
4 *
5 * Copyright (c) 2022 Beau Belgrave <beaub@linux.microsoft.com>
6 */
7
8#define _GNU_SOURCE
9#include <sched.h>
10
11#include <errno.h>
12#include <linux/user_events.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <fcntl.h>
16#include <sys/ioctl.h>
17#include <sys/stat.h>
18#include <unistd.h>
19#include <asm/unistd.h>
20
21#include "../kselftest_harness.h"
22#include "user_events_selftests.h"
23
24const char *data_file = "/sys/kernel/tracing/user_events_data";
25const char *enable_file = "/sys/kernel/tracing/events/user_events/__abi_event/enable";
26
27static int change_event(bool enable)
28{
29	int fd = open(enable_file, O_RDWR);
30	int ret;
31
32	if (fd < 0)
33		return -1;
34
35	if (enable)
36		ret = write(fd, "1", 1);
37	else
38		ret = write(fd, "0", 1);
39
40	close(fd);
41
42	if (ret == 1)
43		ret = 0;
44	else
45		ret = -1;
46
47	return ret;
48}
49
50static int reg_enable(void *enable, int size, int bit)
51{
52	struct user_reg reg = {0};
53	int fd = open(data_file, O_RDWR);
54	int ret;
55
56	if (fd < 0)
57		return -1;
58
59	reg.size = sizeof(reg);
60	reg.name_args = (__u64)"__abi_event";
61	reg.enable_bit = bit;
62	reg.enable_addr = (__u64)enable;
63	reg.enable_size = size;
64
65	ret = ioctl(fd, DIAG_IOCSREG, &reg);
66
67	close(fd);
68
69	return ret;
70}
71
72static int reg_disable(void *enable, int bit)
73{
74	struct user_unreg reg = {0};
75	int fd = open(data_file, O_RDWR);
76	int ret;
77
78	if (fd < 0)
79		return -1;
80
81	reg.size = sizeof(reg);
82	reg.disable_bit = bit;
83	reg.disable_addr = (__u64)enable;
84
85	ret = ioctl(fd, DIAG_IOCSUNREG, &reg);
86
87	close(fd);
88
89	return ret;
90}
91
92FIXTURE(user) {
93	int check;
94	long check_long;
95	bool umount;
96};
97
98FIXTURE_SETUP(user) {
99	USER_EVENT_FIXTURE_SETUP(return, self->umount);
100
101	change_event(false);
102	self->check = 0;
103	self->check_long = 0;
104}
105
106FIXTURE_TEARDOWN(user) {
107	USER_EVENT_FIXTURE_TEARDOWN(self->umount);
108}
109
110TEST_F(user, enablement) {
111	/* Changes should be reflected immediately */
112	ASSERT_EQ(0, self->check);
113	ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
114	ASSERT_EQ(0, change_event(true));
115	ASSERT_EQ(1, self->check);
116	ASSERT_EQ(0, change_event(false));
117	ASSERT_EQ(0, self->check);
118
119	/* Ensure kernel clears bit after disable */
120	ASSERT_EQ(0, change_event(true));
121	ASSERT_EQ(1, self->check);
122	ASSERT_EQ(0, reg_disable(&self->check, 0));
123	ASSERT_EQ(0, self->check);
124
125	/* Ensure doesn't change after unreg */
126	ASSERT_EQ(0, change_event(true));
127	ASSERT_EQ(0, self->check);
128	ASSERT_EQ(0, change_event(false));
129}
130
131TEST_F(user, bit_sizes) {
132	/* Allow 0-31 bits for 32-bit */
133	ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
134	ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 31));
135	ASSERT_NE(0, reg_enable(&self->check, sizeof(int), 32));
136	ASSERT_EQ(0, reg_disable(&self->check, 0));
137	ASSERT_EQ(0, reg_disable(&self->check, 31));
138
139#if BITS_PER_LONG == 8
140	/* Allow 0-64 bits for 64-bit */
141	ASSERT_EQ(0, reg_enable(&self->check_long, sizeof(long), 63));
142	ASSERT_NE(0, reg_enable(&self->check_long, sizeof(long), 64));
143	ASSERT_EQ(0, reg_disable(&self->check_long, 63));
144#endif
145
146	/* Disallowed sizes (everything beside 4 and 8) */
147	ASSERT_NE(0, reg_enable(&self->check, 1, 0));
148	ASSERT_NE(0, reg_enable(&self->check, 2, 0));
149	ASSERT_NE(0, reg_enable(&self->check, 3, 0));
150	ASSERT_NE(0, reg_enable(&self->check, 5, 0));
151	ASSERT_NE(0, reg_enable(&self->check, 6, 0));
152	ASSERT_NE(0, reg_enable(&self->check, 7, 0));
153	ASSERT_NE(0, reg_enable(&self->check, 9, 0));
154	ASSERT_NE(0, reg_enable(&self->check, 128, 0));
155}
156
157TEST_F(user, forks) {
158	int i;
159
160	/* Ensure COW pages get updated after fork */
161	ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
162	ASSERT_EQ(0, self->check);
163
164	if (fork() == 0) {
165		/* Force COW */
166		self->check = 0;
167
168		/* Up to 1 sec for enablement */
169		for (i = 0; i < 10; ++i) {
170			usleep(100000);
171
172			if (self->check)
173				exit(0);
174		}
175
176		exit(1);
177	}
178
179	/* Allow generous time for COW, then enable */
180	usleep(100000);
181	ASSERT_EQ(0, change_event(true));
182
183	ASSERT_NE(-1, wait(&i));
184	ASSERT_EQ(0, WEXITSTATUS(i));
185
186	/* Ensure child doesn't disable parent */
187	if (fork() == 0)
188		exit(reg_disable(&self->check, 0));
189
190	ASSERT_NE(-1, wait(&i));
191	ASSERT_EQ(0, WEXITSTATUS(i));
192	ASSERT_EQ(1, self->check);
193	ASSERT_EQ(0, change_event(false));
194	ASSERT_EQ(0, self->check);
195}
196
197/* Waits up to 1 sec for enablement */
198static int clone_check(void *check)
199{
200	int i;
201
202	for (i = 0; i < 10; ++i) {
203		usleep(100000);
204
205		if (*(int *)check)
206			return 0;
207	}
208
209	return 1;
210}
211
212TEST_F(user, clones) {
213	int i, stack_size = 4096;
214	void *stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
215			   MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK,
216			   -1, 0);
217
218	ASSERT_NE(MAP_FAILED, stack);
219	ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0));
220	ASSERT_EQ(0, self->check);
221
222	/* Shared VM should see enablements */
223	ASSERT_NE(-1, clone(&clone_check, stack + stack_size,
224			    CLONE_VM | SIGCHLD, &self->check));
225
226	ASSERT_EQ(0, change_event(true));
227	ASSERT_NE(-1, wait(&i));
228	ASSERT_EQ(0, WEXITSTATUS(i));
229	munmap(stack, stack_size);
230	ASSERT_EQ(0, change_event(false));
231}
232
233int main(int argc, char **argv)
234{
235	return test_harness_run(argc, argv);
236}
237