1 /* Copyright (C) 1991-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <string.h>
19 #include <unistd.h>
20
21 #include <hurd.h>
22 #include <hurd/port.h>
23
24 /* Make PATH be the root directory (the starting point for absolute
25 paths). Note that while on traditional UNIX systems this call is
26 restricted to the super-user, it isn't on the Hurd. */
27 int
chroot(const char * path)28 chroot (const char *path)
29 {
30 const char *lookup;
31 size_t len;
32 file_t dir, root;
33 error_t err;
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 (path);
38 if (len >= 2 && path[len - 2] == '/' && path[len - 1] == '.')
39 lookup = path;
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, path, 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 /* Prevent going through DIR's .. */
58 err = __file_reparent (dir, MACH_PORT_NULL, &root);
59 __mach_port_deallocate (__mach_task_self (), dir);
60 if (err)
61 return __hurd_fail (err);
62
63 _hurd_port_set (&_hurd_ports[INIT_PORT_CRDIR], root);
64 return 0;
65 }
66