1 /* Copyright (C) 1991-2021 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 <unistd.h>
19 #include <hurd.h>
20 #include <hurd/paths.h>
21 #include <fcntl.h>
22 #include <string.h>
23
24 /* Read the contents of the symbolic link FILE_NAME into no more than
25 LEN bytes of BUF. The contents are not null-terminated.
26 Returns the number of characters read, or -1 for errors. */
27 ssize_t
__readlink(const char * file_name,char * buf,size_t len)28 __readlink (const char *file_name, char *buf, size_t len)
29 {
30 error_t err;
31 file_t file;
32 struct stat64 st;
33
34 file = __file_name_lookup (file_name, O_READ | O_NOLINK, 0);
35 if (file == MACH_PORT_NULL)
36 return -1;
37
38 err = __io_stat (file, &st);
39 if (! err)
40 if (S_ISLNK (st.st_mode))
41 {
42 char *rbuf = buf;
43
44 err = __io_read (file, &rbuf, &len, 0, len);
45 if (!err && rbuf != buf)
46 {
47 memcpy (buf, rbuf, len);
48 __vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len);
49 }
50 }
51 else
52 err = EINVAL;
53
54 __mach_port_deallocate (__mach_task_self (), file);
55
56 if (err)
57 return __hurd_fail (err);
58 else
59 return len;
60 }
61 weak_alias (__readlink, readlink)
62