external/bsd/am-utils/dist/amd/amfs_link.c

   1 /*      $NetBSD$        */
   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 }