1 /* Duplicate a file descriptor result, avoiding clobbering
2 STD{IN,OUT,ERR}_FILENO, with specific flags.
3
4 Copyright (C) 2001, 2004-2006, 2009-2020 Free Software Foundation, Inc.
5
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <https://www.gnu.org/licenses/>. */
18
19 /* Written by Paul Eggert and Eric Blake. */
20
21 #include <config.h>
22
23 /* Specification. */
24 #include "unistd-safer.h"
25
26 #include <fcntl.h>
27 #include <unistd.h>
28
29 /* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
30 STDERR_FILENO. If FLAG contains O_CLOEXEC, behave like
31 fcntl(F_DUPFD_CLOEXEC) rather than fcntl(F_DUPFD). */
32
33 int
dup_safer_flag(int fd,int flag)34 dup_safer_flag (int fd, int flag)
35 {
36 return fcntl (fd, (flag & O_CLOEXEC) ? F_DUPFD_CLOEXEC : F_DUPFD,
37 STDERR_FILENO + 1);
38 }
39