sysdeps/mach/hurd/faccessat.c

   1 /* Test for access to file, relative to open directory.  Hurd version.
   2    Copyright (C) 2006-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stddef.h>
  22 #include <unistd.h>
  23 #include <sys/types.h>
  24 #include <hurd.h>
  25 #include <hurd/fd.h>
  26
  27 int
  28 faccessat (int fd, const char *file, int type, int flag)
  29 {
  30   error_t err;
  31   file_t port;
  32   int allowed, flags;
  33
  34   if ((flag & AT_EACCESS) == 0)
  35     {
  36       if (fd == AT_FDCWD || file[0] == '/')
  37         return __access (file, type);
  38       __set_errno (ENOTSUP);    /* XXX later */
  39       return -1;
  40     }
  41
  42   port = __file_name_lookup_at (fd, flag &~ AT_EACCESS, file, 0, 0);
  43   if (port == MACH_PORT_NULL)
  44     return -1;
  45
  46   /* Find out what types of access we are allowed to this file.  */
  47   err = __file_check_access (port, &allowed);
  48   __mach_port_deallocate (__mach_task_self (), port);
  49   if (err)
  50     return __hurd_fail (err);
  51
  52   flags = 0;
  53   if (type & R_OK)
  54     flags |= O_READ;
  55   if (type & W_OK)
  56     flags |= O_WRITE;
  57   if (type & X_OK)
  58     flags |= O_EXEC;
  59
  60   if (flags & ~allowed)
  61     /* We are not allowed all the requested types of access.  */
  62     return __hurd_fail (EACCES);
  63
  64   return 0;
  65 }