1 /* Invoke fopen, 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 "stdio-safer.h" 25 26 #include <errno.h> 27 #include <unistd.h> 28 #include "unistd-safer.h" 29 30 #ifndef STDERR_FILENO 31 # define STDERR_FILENO 2 32 #endif 33 34 /* Like fopen, but do not return stdin, stdout, or stderr. */ 35 36 FILE * 37 fopen_safer (char const *file, char const *mode) 38 { 39 FILE *fp = fopen (file, mode); 40 41 if (fp) 42 { 43 int fd = fileno (fp); 44 45 if (0 <= fd && fd <= STDERR_FILENO) 46 { 47 int f = dup_safer (fd); 48 49 if (f < 0) 50 { 51 int e = errno; 52 fclose (fp); 53 errno = e; 54 return NULL; 55 } 56 57 if (fclose (fp) != 0 58 || ! (fp = fdopen (f, mode))) 59 { 60 int e = errno; 61 close (f); 62 errno = e; 63 return NULL; 64 } 65 } 66 } 67 68 return fp; 69 } 70
