xref: /freebsd/tests/sys/fifo/fifo_kqueue.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2020 Jan Kokemüller
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/param.h>
29 #include <sys/event.h>
30 #include <sys/stat.h>
31 
32 #include <errno.h>
33 #include <fcntl.h>
34 #include <limits.h>
35 #include <poll.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <time.h>
39 #include <unistd.h>
40 
41 #include <atf-c.h>
42 
43 ATF_TC_WITHOUT_HEAD(fifo_kqueue__writes);
44 ATF_TC_BODY(fifo_kqueue__writes, tc)
45 {
46 	int p[2] = { -1, -1 };
47 
48 	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
49 
50 	ATF_REQUIRE((p[0] = open("testfifo",
51 	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
52 	ATF_REQUIRE((p[1] = open("testfifo",
53 	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
54 
55 	int kq = kqueue();
56 	ATF_REQUIRE(kq >= 0);
57 
58 	struct kevent kev[32];
59 	EV_SET(&kev[0], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, 0);
60 	EV_SET(&kev[1], p[1], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
61 
62 	ATF_REQUIRE(kevent(kq, kev, 2, NULL, 0, NULL) == 0);
63 
64 	/* A new writer should immediately get a EVFILT_WRITE event. */
65 
66 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
67 	    &(struct timespec) { 0, 0 }) == 1);
68 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
69 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
70 	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
71 	ATF_REQUIRE(kev[0].fflags == 0);
72 	ATF_REQUIRE(kev[0].data == 16384);
73 	ATF_REQUIRE(kev[0].udata == 0);
74 
75 	/* Filling up the pipe should make the EVFILT_WRITE disappear. */
76 
77 	char c = 0;
78 	ssize_t r;
79 	while ((r = write(p[1], &c, 1)) == 1) {
80 	}
81 	ATF_REQUIRE(r < 0);
82 	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
83 
84 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
85 	    &(struct timespec) { 0, 0 }) == 0);
86 
87 	/* Reading (PIPE_BUF - 1) bytes will not trigger a EVFILT_WRITE yet. */
88 
89 	for (int i = 0; i < PIPE_BUF - 1; ++i) {
90 		ATF_REQUIRE(read(p[0], &c, 1) == 1);
91 	}
92 
93 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
94 	    &(struct timespec) { 0, 0 }) == 0);
95 
96 	/* Reading one additional byte triggers the EVFILT_WRITE. */
97 
98 	ATF_REQUIRE(read(p[0], &c, 1) == 1);
99 
100 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
101 	    &(struct timespec) { 0, 0 }) == 1);
102 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
103 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
104 	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
105 	ATF_REQUIRE(kev[0].fflags == 0);
106 	ATF_REQUIRE(kev[0].data == PIPE_BUF);
107 	ATF_REQUIRE(kev[0].udata == 0);
108 
109 	/*
110 	 * Reading another byte triggers the EVFILT_WRITE again with a changed
111 	 * 'data' field.
112 	 */
113 
114 	ATF_REQUIRE(read(p[0], &c, 1) == 1);
115 
116 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
117 	    &(struct timespec) { 0, 0 }) == 1);
118 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
119 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
120 	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
121 	ATF_REQUIRE(kev[0].fflags == 0);
122 	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
123 	ATF_REQUIRE(kev[0].udata == 0);
124 
125 	/*
126 	 * Closing the read end should make a EV_EOF appear but leave the 'data'
127 	 * field unchanged.
128 	 */
129 
130 	ATF_REQUIRE(close(p[0]) == 0);
131 
132 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev), NULL) == 1);
133 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
134 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
135 	ATF_REQUIRE(kev[0].flags == (EV_CLEAR | EV_EOF));
136 	ATF_REQUIRE(kev[0].fflags == 0);
137 	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
138 	ATF_REQUIRE(kev[0].udata == 0);
139 
140 	ATF_REQUIRE(close(kq) == 0);
141 	ATF_REQUIRE(close(p[1]) == 0);
142 }
143 
144 ATF_TC_WITHOUT_HEAD(fifo_kqueue__connecting_reader);
145 ATF_TC_BODY(fifo_kqueue__connecting_reader, tc)
146 {
147 	int p[2] = { -1, -1 };
148 
149 	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
150 
151 	ATF_REQUIRE((p[0] = open("testfifo",
152 	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
153 	ATF_REQUIRE((p[1] = open("testfifo",
154 	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
155 
156 	int kq = kqueue();
157 	ATF_REQUIRE(kq >= 0);
158 
159 	struct kevent kev[32];
160 	EV_SET(&kev[0], p[1], EVFILT_WRITE, EV_ADD | EV_CLEAR, 0, 0, 0);
161 	EV_SET(&kev[1], p[1], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
162 
163 	ATF_REQUIRE(kevent(kq, kev, 2, NULL, 0, NULL) == 0);
164 
165 	/* A new writer should immediately get a EVFILT_WRITE event. */
166 
167 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
168 	    &(struct timespec) { 0, 0 }) == 1);
169 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
170 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
171 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
172 	    &(struct timespec) { 0, 0 }) == 0);
173 
174 	/*
175 	 * Filling the pipe, reading (PIPE_BUF + 1) bytes, then closing the
176 	 * read end leads to a EVFILT_WRITE with EV_EOF set.
177 	 */
178 
179 	char c = 0;
180 	ssize_t r;
181 	while ((r = write(p[1], &c, 1)) == 1) {
182 	}
183 	ATF_REQUIRE(r < 0);
184 	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
185 
186 	for (int i = 0; i < PIPE_BUF + 1; ++i) {
187 		ATF_REQUIRE(read(p[0], &c, 1) == 1);
188 	}
189 
190 	ATF_REQUIRE(close(p[0]) == 0);
191 
192 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev), NULL) == 1);
193 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
194 	ATF_REQUIRE((kev[0].flags & EV_EOF) != 0);
195 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
196 	    &(struct timespec) { 0, 0 }) == 0);
197 
198 	/* Opening the reader again must trigger the EVFILT_WRITE. */
199 
200 	ATF_REQUIRE((p[0] = open("testfifo",
201 	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
202 
203 	r = kevent(kq, NULL, 0, kev, nitems(kev), &(struct timespec) { 1, 0 });
204 	ATF_REQUIRE(r == 1);
205 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[1]);
206 	ATF_REQUIRE(kev[0].filter == EVFILT_WRITE);
207 	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
208 	ATF_REQUIRE(kev[0].fflags == 0);
209 	ATF_REQUIRE(kev[0].data == PIPE_BUF + 1);
210 	ATF_REQUIRE(kev[0].udata == 0);
211 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
212 	    &(struct timespec) { 0, 0 }) == 0);
213 
214 	ATF_REQUIRE(close(kq) == 0);
215 	ATF_REQUIRE(close(p[0]) == 0);
216 	ATF_REQUIRE(close(p[1]) == 0);
217 }
218 
219 /* Check that EVFILT_READ behaves sensibly on a FIFO reader. */
220 ATF_TC_WITHOUT_HEAD(fifo_kqueue__reads);
221 ATF_TC_BODY(fifo_kqueue__reads, tc)
222 {
223 	struct kevent kev[32];
224 	ssize_t bytes, i, n;
225 	int kq, p[2];
226 	char c;
227 
228 	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
229 
230 	ATF_REQUIRE((p[0] = open("testfifo",
231 	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
232 	ATF_REQUIRE((p[1] = open("testfifo",
233 	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
234 
235 	bytes = 0;
236 	c = 0;
237 	while ((n = write(p[1], &c, 1)) == 1)
238 		bytes++;
239 	ATF_REQUIRE(n < 0);
240 	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
241 	ATF_REQUIRE(bytes > 1);
242 
243 	for (i = 0; i < bytes / 2; i++)
244 		ATF_REQUIRE(read(p[0], &c, 1) == 1);
245 	bytes -= i;
246 
247 	kq = kqueue();
248 	ATF_REQUIRE(kq >= 0);
249 
250 	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
251 
252 	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
253 
254 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
255 	    &(struct timespec){ 0, 0 }) == 1);
256 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
257 	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
258 	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
259 	ATF_REQUIRE(kev[0].fflags == 0);
260 	ATF_REQUIRE(kev[0].data == bytes);
261 	ATF_REQUIRE(kev[0].udata == 0);
262 
263 	while (bytes-- > 0)
264 		ATF_REQUIRE(read(p[0], &c, 1) == 1);
265 	n = read(p[0], &c, 1);
266 	ATF_REQUIRE(n < 0);
267 	ATF_REQUIRE(errno == EAGAIN || errno == EWOULDBLOCK);
268 
269 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
270 	    &(struct timespec) { 0, 0 }) == 0);
271 
272 	ATF_REQUIRE(close(kq) == 0);
273 	ATF_REQUIRE(close(p[0]) == 0);
274 	ATF_REQUIRE(close(p[1]) == 0);
275 }
276 
277 ATF_TC_WITHOUT_HEAD(fifo_kqueue__read_eof_wakeups);
278 ATF_TC_BODY(fifo_kqueue__read_eof_wakeups, tc)
279 {
280 	int p[2] = { -1, -1 };
281 
282 	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
283 
284 	ATF_REQUIRE((p[0] = open("testfifo",
285 	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
286 	ATF_REQUIRE((p[1] = open("testfifo",
287 	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
288 
289 	int kq = kqueue();
290 	ATF_REQUIRE(kq >= 0);
291 
292 	struct kevent kev[32];
293 
294 	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
295 	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
296 
297 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
298 	    &(struct timespec) { 0, 0 }) == 0);
299 
300 	/*
301 	 * Closing the writer must trigger a EVFILT_READ edge with EV_EOF set.
302 	 */
303 
304 	ATF_REQUIRE(close(p[1]) == 0);
305 
306 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
307 	    &(struct timespec) { 0, 0 }) == 1);
308 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
309 	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
310 	ATF_REQUIRE(kev[0].flags == (EV_EOF | EV_CLEAR));
311 	ATF_REQUIRE(kev[0].fflags == 0);
312 	ATF_REQUIRE(kev[0].data == 0);
313 	ATF_REQUIRE(kev[0].udata == 0);
314 
315 	/*
316 	 * Trying to read from a closed pipe should not trigger EVFILT_READ
317 	 * edges.
318 	 */
319 
320 	char c;
321 	ATF_REQUIRE(read(p[0], &c, 1) == 0);
322 
323 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
324 	    &(struct timespec) { 0, 0 }) == 0);
325 
326 	ATF_REQUIRE(close(kq) == 0);
327 	ATF_REQUIRE(close(p[0]) == 0);
328 }
329 
330 ATF_TC_WITHOUT_HEAD(fifo_kqueue__read_eof_state_when_reconnecting);
331 ATF_TC_BODY(fifo_kqueue__read_eof_state_when_reconnecting, tc)
332 {
333 	int p[2] = { -1, -1 };
334 
335 	ATF_REQUIRE(mkfifo("testfifo", 0600) == 0);
336 
337 	ATF_REQUIRE((p[0] = open("testfifo",
338 	    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
339 	ATF_REQUIRE((p[1] = open("testfifo",
340 	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
341 
342 	int kq = kqueue();
343 	ATF_REQUIRE(kq >= 0);
344 
345 	struct kevent kev[32];
346 
347 	EV_SET(&kev[0], p[0], EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
348 	ATF_REQUIRE(kevent(kq, kev, 1, NULL, 0, NULL) == 0);
349 
350 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
351 	    &(struct timespec) { 0, 0 }) == 0);
352 
353 	/*
354 	 * Closing the writer must trigger a EVFILT_READ edge with EV_EOF set.
355 	 */
356 
357 	ATF_REQUIRE(close(p[1]) == 0);
358 
359 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
360 	    &(struct timespec) { 0, 0 }) == 1);
361 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
362 	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
363 	ATF_REQUIRE(kev[0].flags == (EV_EOF | EV_CLEAR));
364 	ATF_REQUIRE(kev[0].fflags == 0);
365 	ATF_REQUIRE(kev[0].data == 0);
366 	ATF_REQUIRE(kev[0].udata == 0);
367 
368 	/* A new reader shouldn't see the EOF flag. */
369 
370 	{
371 		int new_reader;
372 		ATF_REQUIRE((new_reader = open("testfifo",
373 		    O_RDONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
374 
375 		int new_kq = kqueue();
376 		ATF_REQUIRE(new_kq >= 0);
377 
378 		struct kevent new_kev[32];
379 		EV_SET(&new_kev[0], new_reader, EVFILT_READ, EV_ADD | EV_CLEAR,
380 		    0, 0, 0);
381 		ATF_REQUIRE(kevent(new_kq, new_kev, 1, NULL, 0, NULL) == 0);
382 
383 		ATF_REQUIRE(kevent(new_kq, NULL, 0, new_kev, nitems(new_kev),
384 		    &(struct timespec) { 0, 0 }) == 0);
385 
386 		ATF_REQUIRE(close(new_kq) == 0);
387 		ATF_REQUIRE(close(new_reader) == 0);
388 	}
389 
390 	/*
391 	 * Simply reopening the writer does not trigger the EVFILT_READ again --
392 	 * EV_EOF should be cleared, but there is no data yet so the filter
393 	 * does not trigger.
394 	 */
395 
396 	ATF_REQUIRE((p[1] = open("testfifo",
397 	    O_WRONLY | O_CLOEXEC | O_NONBLOCK)) >= 0);
398 
399 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
400 	    &(struct timespec) { 0, 0 }) == 0);
401 
402 	/* Writing a byte should trigger a EVFILT_READ. */
403 
404 	char c = 0;
405 	ATF_REQUIRE(write(p[1], &c, 1) == 1);
406 
407 	ATF_REQUIRE(kevent(kq, NULL, 0, kev, nitems(kev),
408 	    &(struct timespec) { 0, 0 }) == 1);
409 	ATF_REQUIRE(kev[0].ident == (uintptr_t)p[0]);
410 	ATF_REQUIRE(kev[0].filter == EVFILT_READ);
411 	ATF_REQUIRE(kev[0].flags == EV_CLEAR);
412 	ATF_REQUIRE(kev[0].fflags == 0);
413 	ATF_REQUIRE(kev[0].data == 1);
414 	ATF_REQUIRE(kev[0].udata == 0);
415 
416 	ATF_REQUIRE(close(kq) == 0);
417 	ATF_REQUIRE(close(p[0]) == 0);
418 	ATF_REQUIRE(close(p[1]) == 0);
419 }
420 
421 ATF_TP_ADD_TCS(tp)
422 {
423 	ATF_TP_ADD_TC(tp, fifo_kqueue__writes);
424 	ATF_TP_ADD_TC(tp, fifo_kqueue__connecting_reader);
425 	ATF_TP_ADD_TC(tp, fifo_kqueue__reads);
426 	ATF_TP_ADD_TC(tp, fifo_kqueue__read_eof_wakeups);
427 	ATF_TP_ADD_TC(tp, fifo_kqueue__read_eof_state_when_reconnecting);
428 
429 	return atf_no_error();
430 }
431