amfs_union.c revision 82794 
1/*
2 * Copyright (c) 1997-2001 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. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgment:
21 *      This product includes software developed by the University of
22 *      California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *      %W% (Berkeley) %G%
40 *
41 * $Id: amfs_union.c,v 1.3.2.2 2001/04/14 21:08:21 ezk Exp $
42 *
43 */
44
45/*
46 * Union automounter file system
47 */
48
49#ifdef HAVE_CONFIG_H
50# include <config.h>
51#endif /* HAVE_CONFIG_H */
52#include <am_defs.h>
53#include <amd.h>
54
55/****************************************************************************
56 *** FORWARD DEFINITIONS                                                  ***
57 ****************************************************************************/
58static void amfs_union_mounted(mntfs *mf);
59
60
61/****************************************************************************
62 *** OPS STRUCTURES                                                       ***
63 ****************************************************************************/
64am_ops amfs_union_ops =
65{
66  "union",
67  amfs_auto_match,
68  0,				/* amfs_auto_init */
69  amfs_toplvl_mount,
70  0,
71  amfs_toplvl_umount,
72  0,
73  amfs_auto_lookuppn,
74  amfs_auto_readdir,
75  0,				/* amfs_toplvl_readlink */
76  amfs_union_mounted,
77  0,				/* amfs_toplvl_umounted */
78  find_amfs_auto_srvr,
79  FS_MKMNT | FS_NOTIMEOUT | FS_BACKGROUND | FS_AMQINFO | FS_DIRECTORY
80};
81
82
83/*
84 * Create a reference to a union'ed entry
85 * XXX: this function may not be used anywhere...
86 */
87static int
88create_amfs_union_node(char *dir, voidp arg)
89{
90  if (!STREQ(dir, "/defaults")) {
91    int error = 0;
92    (void) amfs_toplvl_ops.lookuppn(arg, dir, &error, VLOOK_CREATE);
93    if (error > 0) {
94      errno = error;		/* XXX */
95      plog(XLOG_ERROR, "unionfs: could not mount %s: %m", dir);
96    }
97    return error;
98  }
99  return 0;
100}
101
102
103static void
104amfs_union_mounted(mntfs *mf)
105{
106  int i;
107
108  amfs_auto_mkcacheref(mf);
109
110  /*
111   * Having made the union mount point,
112   * populate all the entries...
113   */
114  for (i = 0; i <= last_used_map; i++) {
115    am_node *mp = exported_ap[i];
116    if (mp && mp->am_mnt == mf) {
117      /* return value from create_amfs_union_node is ignored by mapc_keyiter */
118      (void) mapc_keyiter((mnt_map *) mp->am_mnt->mf_private,
119			  (void (*)(char *, voidp)) create_amfs_union_node,
120			  mp);
121      break;
122    }
123  }
124}
125