1/* Invoke pipe, but avoid some glitches.
2 Copyright (C) 2005-2006, 2009-2019 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17/* Written by Jim Meyering. */
18
19#include <config.h>
20
21#include "unistd-safer.h"
22
23#include <unistd.h>
24#include <errno.h>
25
26/* Like pipe, but ensure that neither of the file descriptors is
27 STDIN_FILENO, STDOUT_FILENO, or STDERR_FILENO. Fail with ENOSYS on
28 platforms that lack pipe. */
29
30int
31pipe_safer (int fd[2])
32{
33#if HAVE_PIPE
34 if (pipe (fd) == 0)
35 {
36 int i;
37 for (i = 0; i < 2; i++)
38 {
39 fd[i] = fd_safer (fd[i]);
40 if (fd[i] < 0)
41 {
42 int e = errno;
43 close (fd[1 - i]);
44 errno = e;
45 return -1;
46 }
47 }
48
49 return 0;
50 }
51#else
52 errno = ENOSYS;
53#endif
54
55 return -1;
56}
57