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
24 const char *data_file = "/sys/kernel/tracing/user_events_data";
25 const char *enable_file = "/sys/kernel/tracing/events/user_events/__abi_event/enable";
26
change_event(bool enable)27 static 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
reg_enable(void * enable,int size,int bit)50 static 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, ®);
66
67 close(fd);
68
69 return ret;
70 }
71
reg_disable(void * enable,int bit)72 static 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, ®);
86
87 close(fd);
88
89 return ret;
90 }
91
FIXTURE(user)92 FIXTURE(user) {
93 int check;
94 long check_long;
95 bool umount;
96 };
97
FIXTURE_SETUP(user)98 FIXTURE_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
FIXTURE_TEARDOWN(user)106 FIXTURE_TEARDOWN(user) {
107 USER_EVENT_FIXTURE_TEARDOWN(self->umount);
108 }
109
TEST_F(user,enablement)110 TEST_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
TEST_F(user,bit_sizes)131 TEST_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
TEST_F(user,forks)157 TEST_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 */
clone_check(void * check)198 static 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
TEST_F(user,clones)212 TEST_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
main(int argc,char ** argv)233 int main(int argc, char **argv)
234 {
235 return test_harness_run(argc, argv);
236 }
237