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 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