hurd/hurdfchdir.c

   1 /* Change a port cell to a directory in an open file descriptor.
   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
  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 }