amfs_link.c revision 310490 
1/*
2 * Copyright (c) 1997-2014 Erez Zadok
3 * Copyright (c) 1990 Jan-Simon Pendry
4 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
5 * Copyright (c) 1990 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Jan-Simon Pendry at Imperial College, London.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 *
36 * File: am-utils/amd/amfs_link.c
37 *
38 */
39
40/*
41 * Symbol-link file system
42 */
43
44#ifdef HAVE_CONFIG_H
45# include <config.h>
46#endif /* HAVE_CONFIG_H */
47#include <am_defs.h>
48#include <amd.h>
49
50/* forward declarations */
51static int amfs_link_mount(am_node *mp, mntfs *mf);
52static int amfs_link_umount(am_node *mp, mntfs *mf);
53
54/*
55 * Ops structures
56 */
57am_ops amfs_link_ops =
58{
59  "link",
60  amfs_link_match,
61  0,				/* amfs_link_init */
62  amfs_link_mount,
63  amfs_link_umount,
64  amfs_error_lookup_child,
65  amfs_error_mount_child,
66  amfs_error_readdir,
67  0,				/* amfs_link_readlink */
68  0,				/* amfs_link_mounted */
69  0,				/* amfs_link_umounted */
70  amfs_generic_find_srvr,
71  0,				/* nfs_fs_flags */
72  0,				/* amfs_link_get_wchan */
73#ifdef HAVE_FS_AUTOFS
74  AUTOFS_LINK_FS_FLAGS,
75#endif /* HAVE_FS_AUTOFS */
76};
77
78
79/*
80 * SFS needs a link.
81 */
82char *
83amfs_link_match(am_opts *fo)
84{
85
86  if (!fo->opt_fs) {
87    plog(XLOG_USER, "link: no fs specified");
88    return 0;
89  }
90
91  /*
92   * If the link target points to another mount point, then we could
93   * end up with an unpleasant situation, where the link f/s simply
94   * "assumes" the mntfs of that mount point.
95   *
96   * For example, if the link points to /usr, and /usr is a real ufs
97   * filesystem, then the link f/s will use the inherited ufs mntfs,
98   * and the end result will be that it will become unmountable.
99   *
100   * To prevent this, we use a hack: we prepend a dot ('.') to opt_fs if
101   * its original value was an absolute path, so that it will never match
102   * any other mntfs.
103   *
104   * XXX: a less hacky solution should be used...
105   */
106  if (fo->opt_fs[0] == '/') {
107    char *link_hack = str3cat(NULL, ".", fo->opt_fs, "");
108    if (fo->opt_sublink == NULL || fo->opt_sublink[0] == '\0')
109      fo->opt_sublink = xstrdup(fo->opt_fs);
110    XFREE(fo->opt_fs);
111    fo->opt_fs = link_hack;
112  }
113
114  return xstrdup(fo->opt_fs);
115}
116
117
118static int
119amfs_link_mount(am_node *mp, mntfs *mf)
120{
121  return 0;
122}
123
124
125static int
126amfs_link_umount(am_node *mp, mntfs *mf)
127{
128  return 0;
129}
130