1 /*	$NetBSD: amfs_union.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_union.c
43  *
44  */
45 
46 /*
47  * Union automounter 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 /****************************************************************************
57  *** FORWARD DEFINITIONS                                                  ***
58  ****************************************************************************/
59 static int create_amfs_union_node(char *dir, opaque_t arg);
60 static void amfs_union_mounted(mntfs *mf);
61 
62 
63 /****************************************************************************
64  *** OPS STRUCTURES                                                       ***
65  ****************************************************************************/
66 am_ops amfs_union_ops =
67 {
68   "union",
69   amfs_generic_match,
70   0,				/* amfs_union_init */
71   amfs_toplvl_mount,
72   amfs_toplvl_umount,
73   amfs_generic_lookup_child,
74   amfs_generic_mount_child,
75   amfs_generic_readdir,
76   0,				/* amfs_union_readlink */
77   amfs_union_mounted,
78   0,				/* amfs_union_umounted */
79   amfs_generic_find_srvr,
80   0,				/* amfs_union_get_wchan */
81   FS_MKMNT | FS_NOTIMEOUT | FS_BACKGROUND | FS_AMQINFO | FS_DIRECTORY,
82 #ifdef HAVE_FS_AUTOFS
83   AUTOFS_UNION_FS_FLAGS,
84 #endif /* HAVE_FS_AUTOFS */
85 };
86 
87 
88 /*
89  * Create a reference to a union'ed entry
90  * XXX: this function may not be used anywhere...
91  */
92 static int
93 create_amfs_union_node(char *dir, opaque_t arg)
94 {
95   if (!STREQ(dir, "/defaults")) {
96     int error = 0;
97     am_node *am;
98     am = amfs_generic_lookup_child(arg, dir, &error, VLOOK_CREATE);
99     if (am && error < 0)
100       am = amfs_generic_mount_child(am, &error);
101     if (error > 0) {
102       errno = error;		/* XXX */
103       plog(XLOG_ERROR, "unionfs: could not mount %s: %m", dir);
104     }
105     return error;
106   }
107   return 0;
108 }
109 
110 
111 static void
112 amfs_union_mounted(mntfs *mf)
113 {
114   int index;
115   am_node *mp;
116 
117   amfs_mkcacheref(mf);
118 
119   /*
120    * Having made the union mount point,
121    * populate all the entries...
122    */
123   for (mp = get_first_exported_ap(&index);
124        mp;
125        mp = get_next_exported_ap(&index)) {
126     if (mp->am_mnt == mf) {
127       /* return value from create_amfs_union_node is ignored by mapc_keyiter */
128       (void) mapc_keyiter((mnt_map *) mp->am_mnt->mf_private,
129 			  create_amfs_union_node,
130 			  mp);
131       break;
132     }
133   }
134 }
135