coreutils/lib/dup-safer.c
2001-03-03 19:05:36 +00:00

63 lines
1.4 KiB
C

/* Invoke dup, but avoid some glitches.
Copyright (C) 2001 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* Written by Paul Eggert. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#if HAVE_FCNTL_H
# include <fcntl.h>
#endif
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifndef STDERR_FILENO
# define STDERR_FILENO 2
#endif
#include <unistd-safer.h>
/* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
STDERR_FILENO. */
int
dup_safer (int fd)
{
#ifdef F_DUPFD
return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
#else
int f = dup (fd);
if (0 <= f && f <= STDERR_FILENO)
{
int f1 = dup_safer (f);
int e = errno;
close (f);
errno = e;
f = f1;
}
return f;
#endif
}