1 /* Invoke dup, but avoid some glitches.
2 Copyright (C) 2001, 2004, 2005 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 2, or (at your option)
7 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, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
17 #include <sys/cdefs.h>
18 __RCSID("$NetBSD: dup-safer.c,v 1.2 2016/05/17 14:00:09 christos Exp $");
19
20
21 /* Written by Paul Eggert. */
22
23 #ifdef HAVE_CONFIG_H
24 # include <config.h>
25 #endif
26
27 #include "unistd-safer.h"
28
29 #include <fcntl.h>
30
31 #include <unistd.h>
32 #ifndef STDERR_FILENO
33 # define STDERR_FILENO 2
34 #endif
35
36 /* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
37 STDERR_FILENO. */
38
39 int
dup_safer(int fd)40 dup_safer (int fd)
41 {
42 #ifdef F_DUPFD
43 return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
44 #else
45 /* fd_safer calls us back, but eventually the recursion unwinds and
46 does the right thing. */
47 return fd_safer (dup (fd));
48 #endif
49 }
50