gl/open-safer.c

   1 /* Invoke open, but avoid some glitches.
   2
   3    Copyright (C) 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 2, or (at your option)
   8    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, write to the Free Software Foundation,
  17    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  18
  19 /* Written by Paul Eggert.  */
  20
  21 #include <config.h>
  22
  23 #include "fcntl-safer.h"
  24
  25 #include <fcntl.h>
  26 #include <stdarg.h>
  27 #include "unistd-safer.h"
  28
  29 int
  30 open_safer (char const *file, int flags, ...)
  31 {
  32   mode_t mode = 0;
  33
  34   if (flags & O_CREAT)
  35     {
  36       va_list ap;
  37       va_start (ap, flags);
  38
  39       /* Assume mode_t promotes to int if and only if it is smaller.
  40          This assumption isn't guaranteed by the C standard, but we
  41          don't know of any real-world counterexamples.  */
  42       mode = (sizeof (mode_t) < sizeof (int)
  43               ? va_arg (ap, int)
  44               : va_arg (ap, mode_t));
  45
  46       va_end (ap);
  47     }
  48
  49   return fd_safer (open (file, flags, mode));
  50 }