1 | /* Copyright (C) 1991-2024 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; see the file COPYING.LIB. If |
16 | not, see <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <unistd.h> |
19 | #include <hurd.h> |
20 | #include <hurd/paths.h> |
21 | #include <hurd/fd.h> |
22 | #include <fcntl.h> |
23 | #include <string.h> |
24 | |
25 | /* Read the contents of the symbolic link FILE_NAME relative to FD into no more |
26 | than LEN bytes of BUF. The contents are not null-terminated. |
27 | Returns the number of characters read, or -1 for errors. */ |
28 | ssize_t |
29 | __readlinkat (int fd, const char *file_name, char *buf, size_t len) |
30 | { |
31 | error_t err; |
32 | file_t file_stat; |
33 | struct stat64 st; |
34 | enum retry_type doretry; |
35 | char retryname[1024]; |
36 | file_t file; |
37 | char *rbuf = buf; |
38 | mach_msg_type_number_t nread = len; |
39 | |
40 | file_stat = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0); |
41 | if (file_stat == MACH_PORT_NULL) |
42 | return -1; |
43 | |
44 | err = __io_stat (file_stat, &st); |
45 | if (err) |
46 | goto out; |
47 | if (!S_ISLNK (st.st_mode)) |
48 | { |
49 | err = EINVAL; |
50 | goto out; |
51 | } |
52 | |
53 | err = __dir_lookup (file_stat, "" , O_READ | O_NOLINK, |
54 | 0, &doretry, retryname, &file); |
55 | if (err) |
56 | goto out; |
57 | if (doretry != FS_RETRY_NORMAL || retryname[0] != '\0') |
58 | { |
59 | err = EGRATUITOUS; |
60 | goto out; |
61 | } |
62 | |
63 | err = __io_read (file, &rbuf, &nread, 0, len); |
64 | __mach_port_deallocate (__mach_task_self (), file); |
65 | if (err) |
66 | goto out; |
67 | |
68 | len = nread; |
69 | if (rbuf != buf) |
70 | { |
71 | memcpy (buf, rbuf, len); |
72 | __vm_deallocate (__mach_task_self (), (vm_address_t) rbuf, nread); |
73 | } |
74 | |
75 | |
76 | out: |
77 | __mach_port_deallocate (__mach_task_self (), file_stat); |
78 | |
79 | return err ? __hurd_fail (err) : len; |
80 | } |
81 | weak_alias (__readlinkat, readlinkat) |
82 | libc_hidden_def (readlinkat) |
83 | |