1/* Create a symbolic link named relative to an open directory. Hurd version.
2 Copyright (C) 1991-2022 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 <fcntl.h>
21#include <stddef.h>
22#include <unistd.h>
23#include <hurd.h>
24#include <hurd/paths.h>
25#include <hurd/fd.h>
26#include <string.h>
27
28
29/* Make a link to FROM called TO relative to FD. */
30int
31symlinkat (const char *from, int fd, const char *to)
32{
33 error_t err;
34 file_t dir, node;
35 char *name;
36 const size_t len = strlen (from) + 1;
37 char buf[sizeof (_HURD_SYMLINK) + len];
38
39 /* A symlink is a file whose translator is "/hurd/symlink\0target\0". */
40
41 memcpy (buf, _HURD_SYMLINK, sizeof (_HURD_SYMLINK));
42 memcpy (&buf[sizeof (_HURD_SYMLINK)], from, len);
43
44 dir = __file_name_split_at (fd, to, &name);
45 if (dir == MACH_PORT_NULL)
46 return -1;
47
48 /* Create a new, unlinked node in the target directory. */
49 err = __dir_mkfile (dir, O_WRITE, 0777 & ~_hurd_umask, &node);
50
51 if (! err)
52 {
53 /* Set the node's translator to make it a symlink. */
54 err = __file_set_translator (node,
55 FS_TRANS_EXCL|FS_TRANS_SET,
56 FS_TRANS_EXCL|FS_TRANS_SET, 0,
57 buf, sizeof (_HURD_SYMLINK) + len,
58 MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);
59
60 if (! err)
61 /* Link the node, now a valid symlink, into the target directory. */
62 err = __dir_link (dir, node, name, 1);
63
64 __mach_port_deallocate (__mach_task_self (), node);
65 }
66
67 __mach_port_deallocate (__mach_task_self (), dir);
68
69 if (err)
70 return __hurd_fail (err);
71 return 0;
72}
73

source code of glibc/sysdeps/mach/hurd/symlinkat.c