1  /* Change a port cell to a directory by looking up a name.
       2     Copyright (C) 1999-2023 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  }