etc/autofs/include_nis

   1 #!/usr/bin/awk -f
   2 #-
   3 # Copyright (c) 2017 G. Paul Ziemba
   4 # All rights reserved.
   5 #
   6 #  Redistribution and use in source and binary forms, with or without
   7 #  modification, are permitted provided that the following conditions
   8 #  are met:
   9 #  1. Redistributions of source code must retain the above copyright
  10 #     notice, this list of conditions and the following disclaimer.
  11 #  2. Redistributions in binary form must reproduce the above copyright
  12 #     notice, this list of conditions and the following disclaimer in the
  13 #     documentation and/or other materials provided with the distribution.
  14 #
  15 #  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16 #  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17 #  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18 #  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19 #  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20 #  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21 #  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22 #  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23 #  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24 #  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25 #  SUCH DAMAGE.
  26 #
  27 # $FreeBSD$
  28 #
  29
  30 #
  31 # /etc/autofs/include_nis
  32 #
  33 # automountd Directory Services script for NIS
  34 #
  35 # SYNOPSIS
  36 #       include_nis <mapname>
  37 #
  38 #       include_nis <mapname> <key>
  39 #
  40 # DESCRIPTION
  41 #
  42 #       This script provides a Directory Services map for automountd
  43 #       based on NIS. Please see auto_master(5) for general information.
  44 #
  45 #       The first form, with one argument, emits the entire named NIS map.
  46 #       The second form, with two arguments, emits the map entry for the
  47 #       key given in the second argument.
  48 #
  49 #       This script attempts to determine the names and IP addresses
  50 #       of the local host. Map entries matching the local host are
  51 #       rewritten to specify nullfs mounts (instead of the default
  52 #       NFS) to reduce access overhead in the kernel.
  53 #
  54 #       If a map entry contains multiple location fields, it is not changed.
  55 #
  56
  57
  58 # Populate list of names and IP addrs thet mean "this host"
  59 # into myhostnames array
  60 BEGIN {
  61     #
  62     # Set self hostnames
  63     #
  64
  65     "hostname -s" | getline;
  66     myhostnames[$0] = 1;
  67
  68     "hostname -f" | getline;
  69     myhostnames[$0] = 1;
  70
  71     myhostnames["localhost"] = 1
  72
  73     "hostname -f" | getline;
  74     localdomain=$0
  75     myhostnames["localhost."localdomain] = 1
  76
  77     while ("ifconfig" | getline) {
  78         if ($1 == "inet") {
  79             myhostnames[$2] = 1;
  80         }
  81     }
  82
  83     # debug
  84 #            print "--- hostname list start ----"
  85 #            for (i in myhostnames) {
  86 #                print i
  87 #            }
  88 #            print "--- hostname list end ----"
  89
  90     if (ARGC == 2) {
  91         # mapname only
  92         while ("ypcat -k " ARGV[1] | getline) {
  93             proc_mapline(1)
  94         }
  95     }
  96     if (ARGC == 3) {
  97         # mapname and keyname
  98         while ("ypmatch " ARGV[2] " " ARGV[1] | getline) {
  99             proc_mapline(0)
 100         }
 101     }
 102     exit 0
 103 }
 104
 105 function is_self(hostname)
 106 {
 107     if (myhostnames[hostname]) {
 108         return 1
 109     }
 110     return 0
 111 }
 112
 113 #
 114 # Lines are of the form [key] [-opts] location1 [... locationN]
 115 #
 116 # indicate index of key field with first positional parameter
 117 # 1 means keyfield is the first field
 118 # 0 means keyfield is not present
 119 #
 120 function proc_mapline(keyfield)
 121 {
 122     optionsfield = 0
 123     locationfield = 0
 124     locationcount = 0
 125
 126     for (i=keyfield+1; i <= NF; ++i) {
 127         if (!optionsfield) {
 128             if ($i ~ /^-/) {
 129                 # the first options field found on the line
 130                 optionsfield = i;
 131                 continue
 132             }
 133         }
 134         # Assumption: location contains colon (":")
 135         if (optionsfield && ($i ~ /:/) && ($i !~ /^-/)) {
 136             ++locationcount
 137             if (!locationfield) {
 138                 # the first location field found on the line
 139                 locationfield = i
 140             }
 141         }
 142     }
 143
 144     #
 145     # If location not found, do not modify.
 146     #
 147     # If there is more than one location, do not modify. Rationale:
 148     # Options are applied to all locations. We ca not have "nullfs"
 149     # for only some locations and "nfs" for others for a given
 150     # map key (i.e., a line). The usual reason for multiple
 151     # locations is for redundancy using replicated volumes on
 152     # multiple hosts, so multiple hosts imply fstype=nfs (the
 153     # FreeBSD default for automounter maps).
 154     #
 155     # Hypothetically there could be a map entry with multiple
 156     # locations all with host parts matching "me". In that case,
 157     # it would be safe to rewrite the locations and specify
 158     # nullfs, but the code does not handle this case.
 159     #
 160     if (locationcount == 1) {
 161         #
 162         # We have a line with exactly one location field
 163         #
 164         # Assumption: location has no more than one colon (":")
 165         #
 166         n=split($locationfield,location,":")
 167         if (is_self(location[1])) {
 168             $locationfield = ":" location[2]
 169             if (optionsfield) {
 170                 # append to existing options
 171                 $optionsfield = $optionsfield ",fstype=nullfs"
 172             } else {
 173                 # sneak in ahead of location
 174                 $locationfield = "-fstype=nullfs " $locationfield
 175             }
 176         }
 177     }
 178
 179     print
 180 }