gl/open-safer.c

   1 /* Invoke open, but avoid some glitches.
   2
   3    Copyright (C) 2005, 2006, 2008 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 "fcntl-safer.h"
  23
  24 #include <fcntl.h>
  25 #include <stdarg.h>
  26 #include "unistd-safer.h"
  27
  28 int
  29 open_safer (char const *file, int flags, ...)
  30 {
  31   mode_t mode = 0;
  32
  33   if (flags & O_CREAT)
  34     {
  35       va_list ap;
  36       va_start (ap, flags);
  37
  38       /* Assume mode_t promotes to int if and only if it is smaller.
  39          This assumption isn't guaranteed by the C standard, but we
  40          don't know of any real-world counterexamples.  */
  41       if (sizeof (mode_t) < sizeof (int))
  42         mode = va_arg (ap, int);
  43       else
  44         mode = va_arg (ap, mode_t);
  45
  46       va_end (ap);
  47     }
  48
  49   return fd_safer (open (file, flags, mode));
  50 }