1// SPDX-License-Identifier: GPL-2.0
  2
  3#define _GNU_SOURCE
  4#include <errno.h>
  5#include <fcntl.h>
  6#include <asm/unistd.h>
  7#include <linux/time_types.h>
  8#include <unistd.h>
  9#include <assert.h>
 10#include <signal.h>
 11#include <pthread.h>
 12#include <sys/epoll.h>
 13#include <sys/eventfd.h>
 14#include "../../kselftest_harness.h"
 15
 16#define EVENTFD_TEST_ITERATIONS 100000UL
 17
 18struct error {
 19	int  code;
 20	char msg[512];
 21};
 22
 23static int error_set(struct error *err, int code, const char *fmt, ...)
 24{
 25	va_list args;
 26	int r;
 27
 28	if (code == 0 || !err || err->code != 0)
 29		return code;
 30
 31	err->code = code;
 32	va_start(args, fmt);
 33	r = vsnprintf(err->msg, sizeof(err->msg), fmt, args);
 34	assert((size_t)r < sizeof(err->msg));
 35	va_end(args);
 36
 37	return code;
 38}
 39
 40static inline int sys_eventfd2(unsigned int count, int flags)
 41{
 42	return syscall(__NR_eventfd2, count, flags);
 43}
 44
 45TEST(eventfd_check_flag_rdwr)
 46{
 47	int fd, flags;
 48
 49	fd = sys_eventfd2(0, 0);
 50	ASSERT_GE(fd, 0);
 51
 52	flags = fcntl(fd, F_GETFL);
 53	// since the kernel automatically added O_RDWR.
 54	EXPECT_EQ(flags, O_RDWR);
 55
 56	close(fd);
 57}
 58
 59TEST(eventfd_check_flag_cloexec)
 60{
 61	int fd, flags;
 62
 63	fd = sys_eventfd2(0, EFD_CLOEXEC);
 64	ASSERT_GE(fd, 0);
 65
 66	flags = fcntl(fd, F_GETFD);
 67	ASSERT_GT(flags, -1);
 68	EXPECT_EQ(flags, FD_CLOEXEC);
 69
 70	close(fd);
 71}
 72
 73TEST(eventfd_check_flag_nonblock)
 74{
 75	int fd, flags;
 76
 77	fd = sys_eventfd2(0, EFD_NONBLOCK);
 78	ASSERT_GE(fd, 0);
 79
 80	flags = fcntl(fd, F_GETFL);
 81	ASSERT_GT(flags, -1);
 82	EXPECT_EQ(flags & EFD_NONBLOCK, EFD_NONBLOCK);
 83	EXPECT_EQ(flags & O_RDWR, O_RDWR);
 84
 85	close(fd);
 86}
 87
 88TEST(eventfd_chek_flag_cloexec_and_nonblock)
 89{
 90	int fd, flags;
 91
 92	fd = sys_eventfd2(0, EFD_CLOEXEC|EFD_NONBLOCK);
 93	ASSERT_GE(fd, 0);
 94
 95	flags = fcntl(fd, F_GETFL);
 96	ASSERT_GT(flags, -1);
 97	EXPECT_EQ(flags & EFD_NONBLOCK, EFD_NONBLOCK);
 98	EXPECT_EQ(flags & O_RDWR, O_RDWR);
 99
100	flags = fcntl(fd, F_GETFD);
101	ASSERT_GT(flags, -1);
102	EXPECT_EQ(flags, FD_CLOEXEC);
103
104	close(fd);
105}
106
107static inline void trim_newline(char *str)
108{
109	char *pos = strrchr(str, '\n');
110
111	if (pos)
112		*pos = '\0';
113}
114
115static int verify_fdinfo(int fd, struct error *err, const char *prefix,
116		size_t prefix_len, const char *expect, ...)
117{
118	char buffer[512] = {0, };
119	char path[512] = {0, };
120	va_list args;
121	FILE *f;
122	char *line = NULL;
123	size_t n = 0;
124	int found = 0;
125	int r;
126
127	va_start(args, expect);
128	r = vsnprintf(buffer, sizeof(buffer), expect, args);
129	assert((size_t)r < sizeof(buffer));
130	va_end(args);
131
132	snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", fd);
133	f = fopen(path, "re");
134	if (!f)
135		return error_set(err, -1, "fdinfo open failed for %d", fd);
136
137	while (getline(&line, &n, f) != -1) {
138		char *val;
139
140		if (strncmp(line, prefix, prefix_len))
141			continue;
142
143		found = 1;
144
145		val = line + prefix_len;
146		r = strcmp(val, buffer);
147		if (r != 0) {
148			trim_newline(line);
149			trim_newline(buffer);
150			error_set(err, -1, "%s '%s' != '%s'",
151				  prefix, val, buffer);
152		}
153		break;
154	}
155
156	free(line);
157	fclose(f);
158
159	if (found == 0)
160		return error_set(err, -1, "%s not found for fd %d",
161				 prefix, fd);
162
163	return 0;
164}
165
166TEST(eventfd_check_flag_semaphore)
167{
168	struct error err = {0};
169	int fd, ret;
170
171	fd = sys_eventfd2(0, EFD_SEMAPHORE);
172	ASSERT_GE(fd, 0);
173
174	ret = fcntl(fd, F_GETFL);
175	ASSERT_GT(ret, -1);
176	EXPECT_EQ(ret & O_RDWR, O_RDWR);
177
178	// The semaphore could only be obtained from fdinfo.
179	ret = verify_fdinfo(fd, &err, "eventfd-semaphore: ", 19, "1\n");
180	if (ret != 0)
181		ksft_print_msg("eventfd-semaphore check failed, msg: %s\n",
182				err.msg);
183	EXPECT_EQ(ret, 0);
184
185	close(fd);
186}
187
188/*
189 * A write(2) fails with the error EINVAL if the size of the supplied buffer
190 * is less than 8 bytes, or if an attempt is made to write the value
191 * 0xffffffffffffffff.
192 */
193TEST(eventfd_check_write)
194{
195	uint64_t value = 1;
196	ssize_t size;
197	int fd;
198
199	fd = sys_eventfd2(0, 0);
200	ASSERT_GE(fd, 0);
201
202	size = write(fd, &value, sizeof(int));
203	EXPECT_EQ(size, -1);
204	EXPECT_EQ(errno, EINVAL);
205
206	size = write(fd, &value, sizeof(value));
207	EXPECT_EQ(size, sizeof(value));
208
209	value = (uint64_t)-1;
210	size = write(fd, &value, sizeof(value));
211	EXPECT_EQ(size, -1);
212	EXPECT_EQ(errno, EINVAL);
213
214	close(fd);
215}
216
217/*
218 * A read(2) fails with the error EINVAL if the size of the supplied buffer is
219 * less than 8 bytes.
220 */
221TEST(eventfd_check_read)
222{
223	uint64_t value;
224	ssize_t size;
225	int fd;
226
227	fd = sys_eventfd2(1, 0);
228	ASSERT_GE(fd, 0);
229
230	size = read(fd, &value, sizeof(int));
231	EXPECT_EQ(size, -1);
232	EXPECT_EQ(errno, EINVAL);
233
234	size = read(fd, &value, sizeof(value));
235	EXPECT_EQ(size, sizeof(value));
236	EXPECT_EQ(value, 1);
237
238	close(fd);
239}
240
241
242/*
243 * If EFD_SEMAPHORE was not specified and the eventfd counter has a nonzero
244 * value, then a read(2) returns 8 bytes containing that value, and the
245 * counter's value is reset to zero.
246 * If the eventfd counter is zero at the time of the call to read(2), then the
247 * call fails with the error EAGAIN if the file descriptor has been made nonblocking.
248 */
249TEST(eventfd_check_read_with_nonsemaphore)
250{
251	uint64_t value;
252	ssize_t size;
253	int fd;
254	int i;
255
256	fd = sys_eventfd2(0, EFD_NONBLOCK);
257	ASSERT_GE(fd, 0);
258
259	value = 1;
260	for (i = 0; i < EVENTFD_TEST_ITERATIONS; i++) {
261		size = write(fd, &value, sizeof(value));
262		EXPECT_EQ(size, sizeof(value));
263	}
264
265	size = read(fd, &value, sizeof(value));
266	EXPECT_EQ(size, sizeof(uint64_t));
267	EXPECT_EQ(value, EVENTFD_TEST_ITERATIONS);
268
269	size = read(fd, &value, sizeof(value));
270	EXPECT_EQ(size, -1);
271	EXPECT_EQ(errno, EAGAIN);
272
273	close(fd);
274}
275
276/*
277 * If EFD_SEMAPHORE was specified and the eventfd counter has a nonzero value,
278 * then a read(2) returns 8 bytes containing the value 1, and the counter's
279 * value is decremented by 1.
280 * If the eventfd counter is zero at the time of the call to read(2), then the
281 * call fails with the error EAGAIN if the file descriptor has been made nonblocking.
282 */
283TEST(eventfd_check_read_with_semaphore)
284{
285	uint64_t value;
286	ssize_t size;
287	int fd;
288	int i;
289
290	fd = sys_eventfd2(0, EFD_SEMAPHORE|EFD_NONBLOCK);
291	ASSERT_GE(fd, 0);
292
293	value = 1;
294	for (i = 0; i < EVENTFD_TEST_ITERATIONS; i++) {
295		size = write(fd, &value, sizeof(value));
296		EXPECT_EQ(size, sizeof(value));
297	}
298
299	for (i = 0; i < EVENTFD_TEST_ITERATIONS; i++) {
300		size = read(fd, &value, sizeof(value));
301		EXPECT_EQ(size, sizeof(value));
302		EXPECT_EQ(value, 1);
303	}
304
305	size = read(fd, &value, sizeof(value));
306	EXPECT_EQ(size, -1);
307	EXPECT_EQ(errno, EAGAIN);
308
309	close(fd);
310}
311
312TEST_HARNESS_MAIN