io/openat.c

   1 /* Copyright (C) 2005-2012 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
  26 /* Some mostly-generic code (e.g. sysdeps/posix/getcwd.c) uses this variable
  27    if __ASSUME_ATFCTS is not defined.  */
  28 #ifndef __ASSUME_ATFCTS
  29 int __have_atfcts;
  30 #endif
  31
  32 /* Open FILE with access OFLAG.  Interpret relative paths relative to
  33    the directory associated with FD.  If OFLAG includes O_CREAT, a
  34    third argument is the file protection.  */
  35 int
  36 __openat (fd, file, oflag)
  37      int fd;
  38      const char *file;
  39      int oflag;
  40 {
  41   int mode;
  42
  43   if (file == NULL)
  44     {
  45       __set_errno (EINVAL);
  46       return -1;
  47     }
  48
  49   if (fd != AT_FDCWD && file[0] != '/')
  50     {
  51       /* Check FD is associated with a directory.  */
  52       struct stat64 st;
  53       if (__fxstat64 (_STAT_VER, fd, &st) != 0)
  54         return -1;
  55
  56       if (!S_ISDIR (st.st_mode))
  57         {
  58           __set_errno (ENOTDIR);
  59           return -1;
  60         }
  61     }
  62
  63   if (oflag & O_CREAT)
  64     {
  65       va_list arg;
  66       va_start (arg, oflag);
  67       mode = va_arg (arg, int);
  68       va_end (arg);
  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
  79 int
  80 __openat_2 (fd, file, oflag)
  81      int fd;
  82      const char *file;
  83      int oflag;
  84 {
  85   if (oflag & O_CREAT)
  86     __fortify_fail ("invalid openat call: O_CREAT without mode");
  87
  88   return __openat (fd, file, oflag);
  89 }
  90 stub_warning (__openat_2)