1 /* Change a port cell to a directory in an open file descriptor.
2    Copyright (C) 1999-2022 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
_hurd_change_directory_port_from_fd(struct hurd_port * portcell,int fd)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 }
63