Line data    Source code

       1             : /* Invoke fopen, but avoid some glitches.
       2             : 
       3             :    Copyright (C) 2001, 2004, 2005, 2006 Free Software Foundation, Inc.
       4             : 
       5             :    This program is free software: you can redistribute it and/or modify
       6             :    it under the terms of the GNU General Public License as published by
       7             :    the Free Software Foundation; either version 3 of the License, or
       8             :    (at your option) any later version.
       9             : 
      10             :    This program is distributed in the hope that it will be useful,
      11             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      12             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13             :    GNU General Public License for more details.
      14             : 
      15             :    You should have received a copy of the GNU General Public License
      16             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      17             : 
      18             : /* Written by Paul Eggert.  */
      19             : 
      20             : #include <config.h>
      21             : 
      22             : #include "stdio-safer.h"
      23             : 
      24             : #include <errno.h>
      25             : #include <unistd.h>
      26             : #include "unistd-safer.h"
      27             : 
      28             : #ifndef STDERR_FILENO
      29             : # define STDERR_FILENO 2
      30             : #endif
      31             : 
      32             : /* Like fopen, but do not return stdin, stdout, or stderr.  */
      33             : 
      34             : FILE *
      35         302 : fopen_safer (char const *file, char const *mode)
      36             : {
      37         302 :   FILE *fp = fopen (file, mode);
      38             : 
      39         302 :   if (fp)
      40             :     {
      41         248 :       int fd = fileno (fp);
      42             : 
      43         248 :       if (0 <= fd && fd <= STDERR_FILENO)
      44             :         {
      45           0 :           int f = dup_safer (fd);
      46             : 
      47           0 :           if (f < 0)
      48             :             {
      49           0 :               int e = errno;
      50           0 :               fclose (fp);
      51           0 :               errno = e;
      52           0 :               return NULL;
      53             :             }
      54             : 
      55           0 :           if (fclose (fp) != 0
      56           0 :               || ! (fp = fdopen (f, mode)))
      57             :             {
      58           0 :               int e = errno;
      59           0 :               close (f);
      60           0 :               errno = e;
      61           0 :               return NULL;
      62             :             }
      63             :         }
      64             :     }
      65             : 
      66         302 :   return fp;
      67             : }