io/openat.c

   1 /* Copyright (C) 2005-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <stdarg.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <sys/stat.h>
  24 #include <kernel-features.h>
  25 #include <libc-internal.h>
  26
  27 /* Some mostly-generic code (e.g. sysdeps/posix/getcwd.c) uses this variable
  28    if __ASSUME_ATFCTS is not defined.  */
  29 #ifndef __ASSUME_ATFCTS
  30 int __have_atfcts;
  31 #endif
  32
  33 /* Open FILE with access OFLAG.  Interpret relative paths relative to
  34    the directory associated with FD.  If O_CREAT or O_TMPFILE is in OFLAG, a
  35    third argument is the file protection.  */
  36 int
  37 __openat (int fd, const char *file, int oflag, ...)
  38 {
  39   int mode;
  40
  41   if (file == NULL)
  42     {
  43       __set_errno (EINVAL);
  44       return -1;
  45     }
  46
  47   if (fd != AT_FDCWD && file[0] != '/')
  48     {
  49       /* Check FD is associated with a directory.  */
  50       struct stat64 st;
  51       if (__fxstat64 (_STAT_VER, fd, &st) != 0)
  52         return -1;
  53
  54       if (!S_ISDIR (st.st_mode))
  55         {
  56           __set_errno (ENOTDIR);
  57           return -1;
  58         }
  59     }
  60
  61   if (__OPEN_NEEDS_MODE (oflag))
  62     {
  63       va_list arg;
  64       va_start (arg, oflag);
  65       mode = va_arg (arg, int);
  66       va_end (arg);
  67
  68       ignore_value (mode);
  69     }
  70
  71   __set_errno (ENOSYS);
  72   return -1;
  73 }
  74 libc_hidden_def (__openat)
  75 weak_alias (__openat, openat)
  76 stub_warning (openat)
  77
  78 /* __openat_2 is a generic wrapper that calls __openat.
  79    So give a stub warning for that symbol too.  */
  80 stub_warning (__openat_2)