1 /*	$NetBSD: amfs_link.c,v 1.1.1.2 2009/03/20 20:26:49 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1997-2009 Erez Zadok
5  * Copyright (c) 1990 Jan-Simon Pendry
6  * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
7  * Copyright (c) 1990 The Regents of the University of California.
8  * All rights reserved.
9  *
10  * This code is derived from software contributed to Berkeley by
11  * Jan-Simon Pendry at Imperial College, London.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgment:
23  *      This product includes software developed by the University of
24  *      California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *
42  * File: am-utils/amd/amfs_link.c
43  *
44  */
45 
46 /*
47  * Symbol-link file system
48  */
49 
50 #ifdef HAVE_CONFIG_H
51 # include <config.h>
52 #endif /* HAVE_CONFIG_H */
53 #include <am_defs.h>
54 #include <amd.h>
55 
56 /* forward declarations */
57 static int amfs_link_mount(am_node *mp, mntfs *mf);
58 static int amfs_link_umount(am_node *mp, mntfs *mf);
59 
60 /*
61  * Ops structures
62  */
63 am_ops amfs_link_ops =
64 {
65   "link",
66   amfs_link_match,
67   0,				/* amfs_link_init */
68   amfs_link_mount,
69   amfs_link_umount,
70   amfs_error_lookup_child,
71   amfs_error_mount_child,
72   amfs_error_readdir,
73   0,				/* amfs_link_readlink */
74   0,				/* amfs_link_mounted */
75   0,				/* amfs_link_umounted */
76   amfs_generic_find_srvr,
77   0,				/* nfs_fs_flags */
78   0,				/* amfs_link_get_wchan */
79 #ifdef HAVE_FS_AUTOFS
80   AUTOFS_LINK_FS_FLAGS,
81 #endif /* HAVE_FS_AUTOFS */
82 };
83 
84 
85 /*
86  * SFS needs a link.
87  */
88 char *
89 amfs_link_match(am_opts *fo)
90 {
91 
92   if (!fo->opt_fs) {
93     plog(XLOG_USER, "link: no fs specified");
94     return 0;
95   }
96 
97   /*
98    * If the link target points to another mount point, then we could
99    * end up with an unpleasant situation, where the link f/s simply
100    * "assumes" the mntfs of that mount point.
101    *
102    * For example, if the link points to /usr, and /usr is a real ufs
103    * filesystem, then the link f/s will use the inherited ufs mntfs,
104    * and the end result will be that it will become unmountable.
105    *
106    * To prevent this, we use a hack: we prepend a dot ('.') to opt_fs if
107    * its original value was an absolute path, so that it will never match
108    * any other mntfs.
109    *
110    * XXX: a less hacky solution should be used...
111    */
112   if (fo->opt_fs[0] == '/') {
113     char *link_hack = str3cat(NULL, ".", fo->opt_fs, "");
114     if (fo->opt_sublink == NULL || fo->opt_sublink[0] == '\0')
115       fo->opt_sublink = strdup(fo->opt_fs);
116     XFREE(fo->opt_fs);
117     fo->opt_fs = link_hack;
118   }
119 
120   return strdup(fo->opt_fs);
121 }
122 
123 
124 static int
125 amfs_link_mount(am_node *mp, mntfs *mf)
126 {
127   return 0;
128 }
129 
130 
131 static int
132 amfs_link_umount(am_node *mp, mntfs *mf)
133 {
134   return 0;
135 }
136