1  /* Change a port cell to a directory in an open file descriptor.
       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  
      26  int
      27  _hurd_change_directory_port_from_fd (struct hurd_port *portcell, int fd)
      28  {
      29    int ret;
      30    struct hurd_fd *d = _hurd_fd_get (fd);
      31  
      32    if (!d)
      33      return __hurd_fail (EBADF);
      34  
      35  retry:
      36    HURD_CRITICAL_BEGIN;
      37  
      38    ret = HURD_PORT_USE (&d->port,
      39  		       ({
      40  			 int ret;
      41  			 /* We look up "." to force ENOTDIR if it's not a
      42  			    directory and EACCES if we don't have search
      43  			    permission.  */
      44  			 file_t dir = __file_name_lookup_under (port, ".",
      45  								O_NOTRANS, 0);
      46  			 if (dir == MACH_PORT_NULL)
      47  			   ret = -1;
      48  			 else
      49  			   {
      50  			     _hurd_port_set (portcell, dir);
      51  			     ret = 0;
      52  			   }
      53  			 ret;
      54  		       }));
      55  
      56    HURD_CRITICAL_END;
      57    if (ret == -1 && errno == EINTR)
      58      /* Got a signal while inside an RPC of the critical section, retry again */
      59      goto retry;
      60  
      61    return ret;
      62  }