Don't stomp on existing configs.
[openresolv] / libc.in
1 #!/bin/sh
2 # Copyright (c) 2007-2009 Roy Marples
3 # All rights reserved
4
5 # libc subscriber for resolvconf
6
7 # Redistribution and use in source and binary forms, with or without
8 # modification, are permitted provided that the following conditions
9 # are met:
10 #     * Redistributions of source code must retain the above copyright
11 #       notice, this list of conditions and the following disclaimer.
12 #     * Redistributions in binary form must reproduce the above
13 #       copyright notice, this list of conditions and the following
14 #       disclaimer in the documentation and/or other materials provided
15 #       with the distribution.
16 #
17 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 SYSCONFDIR=@SYSCONFDIR@
30 LIBEXECDIR=@LIBEXECDIR@
31 VARDIR=@VARDIR@
32 IFACEDIR="$VARDIR/interfaces"
33
34 # sed may not be available, and this is faster on small files
35 key_get_value()
36 {
37         local key="$1" value= x= line=
38
39         shift
40         if [ $# -eq 0 ]; then
41                 while read line; do
42                         case "$line" in
43                         "$key"*) echo "${line##$key}";;
44                         esac
45                 done
46         else
47                 for x; do
48                         while read line; do
49                                 case "$line" in
50                                 "$key"*) echo "${line##$key}";;
51                                 esac
52                         done < "$x"
53                 done
54         fi
55 }
56
57 # Support original resolvconf configuration layout
58 # as well as the openresolv config file
59 if [ -f "$SYSCONFDIR"/resolvconf.conf ]; then
60         . "$SYSCONFDIR"/resolvconf.conf
61 elif [ -d "$SYSCONFDIR"/resolvconf ]; then
62         SYSCONFDIR="$SYSCONFDIR/resolvconf/resolv.conf.d"
63         base="$SYSCONFDIR/resolv.conf.d/base"
64         if [ -f "$base" ]; then
65                 name_servers="$(key_get_value "nameserver " "$base")"
66                 search_domains="$(key_get_value "search " "$base")"
67                 if [ -z "$search_domains" ]; then
68                         search_domains="$(key_get_value "domain " "$base")"
69                 fi
70                 resolv_conf_options="$(key_get_value "options " "$base")"
71         fi
72         if [ -f "$SYSCONFDIR"/resolv.conf.d/head ]; then
73                 resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.d/head)"
74         fi
75         if [ -f "$SYSCONFDIR"/resolv.conf.d/tail ]; then
76                 resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.d/tail)"
77         fi
78 fi
79 : ${resolv_conf:=/etc/resolv.conf}
80 : ${libc_restart:=@RESTARTCMD nscd@}
81 : ${list_resolv:=@PREFIX@/sbin/resolvconf -l}
82 if [ "${resolv_conf_head-x}" = x -a -f "$SYSCONFDIR"/resolv.conf.head ]; then
83         resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.head)"
84 fi
85 if [ "${resolv_conf_tail-x}" = x -a -f "$SYSCONFDIR"/resolv.conf.tail ]; then
86         resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.tail)"
87 fi
88
89 uniqify()
90 {
91         local result=
92         while [ -n "$1" ]; do
93                 case " $result " in
94                 *" $1 "*);;
95                 *) result="$result $1";;
96                 esac
97                 shift
98         done
99         echo "${result# *}"
100 }
101
102 case "${resolv_conf_passthrough:-NO}" in
103 [Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
104         newest=
105         for conf in "$IFACEDIR"/*; do
106                 if [ -z "$newest" -o "$conf" -nt "$newest" ]; then
107                         newest="$conf"
108                 fi
109         done
110         [ -z "$newest" ] && exit 0
111         newconf="$(cat "$newest")\n"
112         ;;
113 *)
114         [ -z "$RESOLVCONF" ] && eval "$(@PREFIX@/sbin/resolvconf -v)"
115         newsearch="$(uniqify $search_domains $SEARCH)"
116         newns="$(uniqify $name_servers $NAMESERVERS)"
117
118         # Hold our new resolv.conf in a variable to save on temporary files
119         newconf="# Generated by resolvconf\n"
120         if [ -n "$resolv_conf_head" ]; then
121                 newconf="$newconf$resolv_conf_head\n"
122         fi
123         [ -n "$newsearch" ] && newconf="${newconf}search $newsearch\n"
124         for n in $newns; do
125                 newconf="${newconf}nameserver $n\n"
126         done
127
128         # Now get any configured options
129         opts="$resolv_conf_options${resolv_conf_options:+ }"
130         opts="$opts$($list_resolv | key_get_value "options ")"
131         if [ -n "$opts" ]; then
132                 newconf="${newconf}options"
133                 for opt in $(uniqify $opts); do
134                         newconf="${newconf} $opt"
135                 done
136                 newconf="$newconf\n"
137         fi
138
139         if [ -n "$resolv_conf_tail" ]; then
140                 newconf="$newconf$resolv_conf_tail\n"
141         fi
142         ;;
143 esac
144
145 # Check if the file has actually changed or not
146 if [ -e "$resolv_conf" ]; then
147         [ "$(cat "$resolv_conf")" = "$(printf "$newconf")" ] && exit 0
148 fi
149
150 # Create our resolv.conf now
151 (umask 022; printf "$newconf" >"$resolv_conf")
152 eval $libc_restart
153
154 retval=0
155 # Notify users of the resolver
156 for script in "$LIBEXECDIR"/libc.d/*; do
157         if [ -f "$script" ]; then
158                 if [ -x "$script" ]; then
159                         "$script" "$@"
160                 else
161                         (. "$script" "$@")
162                 fi
163                 retval=$(($retval + $?))
164         fi
165 done
166 exit $retval