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