hurd/hurdchdir.c

   1 /* Change a port cell to a directory by looking up a name.
   2    Copyright (C) 1999-2021 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <hurd.h>
  22 #include <hurd/port.h>
  23 #include <hurd/fd.h>
  24 #include <fcntl.h>
  25 #include <string.h>
  26
  27 int
  28 _hurd_change_directory_port_from_name (struct hurd_port *portcell,
  29                                        const char *name)
  30 {
  31   size_t len;
  32   const char *lookup;
  33   file_t dir;
  34
  35   /* Append trailing "/." to directory name to force ENOTDIR if it's not a
  36      directory and EACCES if we don't have search permission.  */
  37   len = strlen (name);
  38   if (len >= 2 && name[len - 2] == '/' && name[len - 1] == '.')
  39     lookup = name;
  40   else if (len == 0)
  41     /* Special-case empty file name according to POSIX.  */
  42     return __hurd_fail (ENOENT);
  43   else
  44     {
  45       char *n = alloca (len + 3);
  46       memcpy (n, name, len);
  47       n[len] = '/';
  48       n[len + 1] = '.';
  49       n[len + 2] = '\0';
  50       lookup = n;
  51     }
  52
  53   dir = __file_name_lookup (lookup, 0, 0);
  54   if (dir == MACH_PORT_NULL)
  55     return -1;
  56
  57   _hurd_port_set (portcell, dir);
  58   return 0;
  59 }