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
18/* Written by Paul Eggert.  */
19
20#ifdef HAVE_CONFIG_H
21# include <config.h>
22#endif
23
24#include "unistd-safer.h"
25
26#include <fcntl.h>
27
28#include <unistd.h>
29#ifndef STDERR_FILENO
30# define STDERR_FILENO 2
31#endif
32
33/* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
34   STDERR_FILENO.  */
35
36int
37dup_safer (int fd)
38{
39#ifdef F_DUPFD
40  return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
41#else
42  /* fd_safer calls us back, but eventually the recursion unwinds and
43     does the right thing.  */
44  return fd_safer (dup (fd));
45#endif
46}
47