lib/openat-safer.c

   1 /* Invoke openat, but avoid some glitches.
   2
   3    Copyright (C) 2005-2006, 2008-2020 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 <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert for open, ported by Eric Blake for openat.  */
  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 openat_safer (int fd, 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       /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
  39          creates crashing code when 'mode_t' is smaller than 'int'.  */
  40       mode = va_arg (ap, PROMOTED_MODE_T);
  41
  42       va_end (ap);
  43     }
  44
  45   return fd_safer (openat (fd, file, flags, mode));
  46 }