1 /*-
2  * Copyright (c) 2010 Jilles Tjoelker
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/select.h>
30 
31 #include <err.h>
32 #include <stdio.h>
33 #include <unistd.h>
34 
35 /*
36  * Check that pipes can be selected for writing in the reverse direction.
37  */
38 int
39 main(void)
40 {
41 	int pip[2];
42 	fd_set set;
43 	int n;
44 
45 	if (pipe(pip) == -1)
46 		err(1, "FAIL: pipe");
47 
48 	FD_ZERO(&set);
49 	FD_SET(pip[0], &set);
50 	n = select(pip[1] + 1, NULL, &set, NULL, &(struct timeval){ 0, 0 });
51 	if (n != 1)
52 		errx(1, "FAIL: select initial reverse direction");
53 
54 	n = write(pip[0], "x", 1);
55 	if (n != 1)
56 		err(1, "FAIL: write reverse direction");
57 
58 	FD_ZERO(&set);
59 	FD_SET(pip[0], &set);
60 	n = select(pip[1] + 1, NULL, &set, NULL, &(struct timeval){ 0, 0 });
61 	if (n != 1)
62 		errx(1, "FAIL: select reverse direction after write");
63 
64 	printf("PASS\n");
65 
66 	return (0);
67 }
68