1 /* $NetBSD: t_fifo.c,v 1.5 2021/10/02 18:39:15 thorpej Exp $ */
2
3 /*-
4 * Copyright (c) 2021 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __COPYRIGHT("@(#) Copyright (c) 2021\
34 The NetBSD Foundation, inc. All rights reserved.");
35 __RCSID("$NetBSD: t_fifo.c,v 1.5 2021/10/02 18:39:15 thorpej Exp $");
36
37 #include <sys/event.h>
38 #include <sys/stat.h>
39
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <inttypes.h>
47
48 #include <atf-c.h>
49
50 static const char fifo_path[] = "fifo";
51
52 static void
fifo_support(void)53 fifo_support(void)
54 {
55 errno = 0;
56 if (mkfifo(fifo_path, 0600) == 0) {
57 ATF_REQUIRE(unlink(fifo_path) == 0);
58 return;
59 }
60
61 if (errno == EOPNOTSUPP) {
62 atf_tc_skip("the kernel does not support FIFOs");
63 } else {
64 atf_tc_fail("mkfifo(2) failed");
65 }
66 }
67
68 ATF_TC_WITH_CLEANUP(fifo);
ATF_TC_HEAD(fifo,tc)69 ATF_TC_HEAD(fifo, tc)
70 {
71 atf_tc_set_md_var(tc, "descr", "Checks EVFILT_WRITE on fifo");
72 }
ATF_TC_BODY(fifo,tc)73 ATF_TC_BODY(fifo, tc)
74 {
75 const struct timespec to = { 0, 0 };
76 struct kevent event[1];
77 char *buf;
78 int rfd, wfd, kq;
79 long pipe_buf;
80
81 fifo_support();
82
83 ATF_REQUIRE(mkfifo(fifo_path, 0600) == 0);
84 ATF_REQUIRE((rfd = open(fifo_path, O_RDONLY | O_NONBLOCK)) >= 0);
85 ATF_REQUIRE((wfd = open(fifo_path, O_WRONLY | O_NONBLOCK)) >= 0);
86 ATF_REQUIRE((kq = kqueue()) >= 0);
87
88 /* Get the maximum atomic pipe write size. */
89 pipe_buf = fpathconf(wfd, _PC_PIPE_BUF);
90 ATF_REQUIRE(pipe_buf > 1);
91
92 buf = malloc(pipe_buf);
93 ATF_REQUIRE(buf != NULL);
94
95 EV_SET(&event[0], wfd, EVFILT_WRITE, EV_ADD|EV_ENABLE, 0, 0, 0);
96 ATF_REQUIRE(kevent(kq, event, 1, NULL, 0, NULL) == 0);
97
98 /* We expect the FIFO to be writable. */
99 ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 1);
100 ATF_REQUIRE(event[0].ident == (uintptr_t)wfd);
101 ATF_REQUIRE(event[0].filter == EVFILT_WRITE);
102
103 /*
104 * Write data into the FIFO until it is full, which is
105 * defined as insufficient buffer space to hold the
106 * maximum atomic pipe write size.
107 */
108 while (write(wfd, buf, pipe_buf) != -1) {
109 continue;
110 }
111 ATF_REQUIRE(errno == EAGAIN);
112
113 /* We expect the FIFO to no longer be writable. */
114 ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 0);
115
116 /* Read a single byte of data from the FIFO. */
117 ATF_REQUIRE(read(rfd, buf, 1) == 1);
118
119 /*
120 * Because we have read only a single byte out, there will
121 * be insufficient space for a pipe_buf-sized message, so
122 * the FIFO should still not be writable.
123 */
124 ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 0);
125
126 /*
127 * Now read enough so that exactly pipe_buf space should be
128 * available. The FIFO should be writable after that.
129 */
130 ATF_REQUIRE(read(rfd, buf, pipe_buf - 1) == pipe_buf - 1);
131 ATF_REQUIRE(kevent(kq, NULL, 0, event, 1, &to) == 1);
132 ATF_REQUIRE(event[0].ident == (uintptr_t)wfd);
133 ATF_REQUIRE(event[0].filter == EVFILT_WRITE);
134
135 (void)close(wfd);
136 (void)close(rfd);
137 (void)close(kq);
138 }
139
ATF_TC_CLEANUP(fifo,tc)140 ATF_TC_CLEANUP(fifo, tc)
141 {
142 (void)unlink(fifo_path);
143 }
144
ATF_TP_ADD_TCS(tp)145 ATF_TP_ADD_TCS(tp)
146 {
147 ATF_TP_ADD_TC(tp, fifo);
148
149 return atf_no_error();
150 }
151