1 /*
2 * Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
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 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "tests.h"
29 #include <limits.h>
30 #include <unistd.h>
31 #include <sys/resource.h>
32
33 static void
move_fd(int * from,int * to)34 move_fd(int *from, int *to)
35 {
36 for (; *to > *from; --*to) {
37 if (dup2(*from, *to) != *to)
38 continue;
39 close(*from);
40 *from = *to;
41 break;
42 }
43 }
44
45 void
pipe_maxfd(int pipefd[2])46 pipe_maxfd(int pipefd[2])
47 {
48 struct rlimit rlim;
49 if (getrlimit(RLIMIT_NOFILE, &rlim))
50 perror_msg_and_fail("getrlimit");
51 if (rlim.rlim_cur < rlim.rlim_max) {
52 struct rlimit rlim_new;
53 rlim_new.rlim_cur = rlim_new.rlim_max = rlim.rlim_max;
54 if (!setrlimit(RLIMIT_NOFILE, &rlim_new))
55 rlim.rlim_cur = rlim.rlim_max;
56 }
57
58 if (pipe(pipefd))
59 perror_msg_and_fail("pipe");
60
61 int max_fd = (rlim.rlim_cur > 0 && rlim.rlim_cur < INT_MAX)
62 ? rlim.rlim_cur - 1 : INT_MAX;
63
64 move_fd(&pipefd[1], &max_fd);
65 --max_fd;
66 move_fd(&pipefd[0], &max_fd);
67 }
68