1#!/bin/sh
2# Copyright (c) 2007-2014 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
29SYSCONFDIR=@SYSCONFDIR@
30LIBEXECDIR=@LIBEXECDIR@
31VARDIR=@VARDIR@
32IFACEDIR="$VARDIR/interfaces"
33NL="
34"
35
36# sed may not be available, and this is faster on small files
37key_get_value()
38{
39	local key="$1" x= line=
40
41	shift
42	if [ $# -eq 0 ]; then
43		while read -r line; do
44			case "$line" in
45			"$key"*) echo "${line##$key}";;
46			esac
47		done
48	else
49		for x do
50			while read -r line; do
51				case "$line" in
52				"$key"*) echo "${line##$key}";;
53				esac
54			done < "$x"
55		done
56	fi
57}
58
59keys_remove()
60{
61	local key x line found
62
63	while read -r line; do
64		found=false
65		for key do
66			case "$line" in
67			"$key"*|"#"*|" "*|"	"*|"") found=true;;
68			esac
69			$found && break
70		done
71		$found || echo "$line"
72	done
73}
74
75local_nameservers="127.* 0.0.0.0 255.255.255.255 ::1"
76
77# Support original resolvconf configuration layout
78# as well as the openresolv config file
79if [ -f "$SYSCONFDIR"/resolvconf.conf ]; then
80	. "$SYSCONFDIR"/resolvconf.conf
81elif [ -d "$SYSCONFDIR"/resolvconf ]; then
82	SYSCONFDIR="$SYSCONFDIR/resolvconf/resolv.conf.d"
83	base="$SYSCONFDIR/resolv.conf.d/base"
84	if [ -f "$base" ]; then
85		prepend_nameservers="$(key_get_value "nameserver " "$base")"
86		domain="$(key_get_value "domain " "$base")"
87		prepend_search="$(key_get_value "search " "$base")"
88		resolv_conf_options="$(key_get_value "options " "$base")"
89		resolv_conf_sortlist="$(key_get_value "sortlist " "$base")"
90	fi
91	if [ -f "$SYSCONFDIR"/resolv.conf.d/head ]; then
92		resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.d/head)"
93	fi
94	if [ -f "$SYSCONFDIR"/resolv.conf.d/tail ]; then
95		resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.d/tail)"
96	fi
97fi
98: ${resolv_conf:=/etc/resolv.conf}
99: ${libc_service:=nscd}
100: ${libc_restart:=@RESTARTCMD ${libc_service}@}
101: ${list_resolv:=@SBINDIR@/resolvconf -l}
102if [ "${resolv_conf_head-x}" = x -a -f "$SYSCONFDIR"/resolv.conf.head ]; then
103	resolv_conf_head="$(cat "${SYSCONFDIR}"/resolv.conf.head)"
104fi
105if [ "${resolv_conf_tail-x}" = x -a -f "$SYSCONFDIR"/resolv.conf.tail ]; then
106	resolv_conf_tail="$(cat "$SYSCONFDIR"/resolv.conf.tail)"
107fi
108
109backup=true
110signature="# Generated by resolvconf"
111 
112uniqify()
113{
114	local result=
115	while [ -n "$1" ]; do
116		case " $result " in
117		*" $1 "*);;
118		*) result="$result $1";;
119		esac
120		shift
121	done
122	echo "${result# *}"
123}
124
125case "${resolv_conf_passthrough:-NO}" in
126[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
127	backup=false
128	newest=
129	for conf in "$IFACEDIR"/*; do
130		if [ -z "$newest" -o "$conf" -nt "$newest" ]; then
131			newest="$conf"
132		fi
133	done
134	[ -z "$newest" ] && exit 0
135	newconf="$(cat "$newest")$NL"
136	;;
137/dev/null|[Nn][Uu][Ll][Ll])
138	: ${resolv_conf_local_only:=NO}
139	if [ "$local_nameservers" = "127.* 0.0.0.0 255.255.255.255 ::1" ]; then
140		local_nameservers=
141	fi
142	# Need to overwrite our variables.
143	eval "$(@SBINDIR@/resolvconf -V)"
144	;;
145
146*)
147	[ -z "$RESOLVCONF" ] && eval "$(@SBINDIR@/resolvconf -v)"
148	;;
149esac
150case "${resolv_conf_passthrough:-NO}" in
151[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1) ;;
152*)
153	: ${domain:=$DOMAIN}
154	newsearch="$(uniqify $prepend_search $SEARCH $append_search)"
155	NS="$LOCALNAMESERVERS $NAMESERVERS"
156	newns=
157	gotlocal=false
158	for n in $(uniqify $prepend_nameservers $NS $append_nameservers); do
159		add=true
160		islocal=false
161		for l in $local_nameservers; do
162			case "$n" in
163			$l) islocal=true; gotlocal=true; break;;
164			esac
165		done
166		if ! $islocal; then
167			case "${resolv_conf_local_only:-YES}" in
168			[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|[Oo][Nn]|1)
169				$gotlocal && add=false;;
170			esac
171		fi
172		$add && newns="$newns $n"
173	done
174
175	# Hold our new resolv.conf in a variable to save on temporary files
176	newconf="$signature$NL"
177	if [ -n "$resolv_conf_head" ]; then
178		newconf="$newconf$resolv_conf_head$NL"
179	fi
180
181	[ -n "$domain" ] && newconf="${newconf}domain $domain$NL"
182	if [ -n "$newsearch" -a "$newsearch" != "$domain" ]; then
183		newconf="${newconf}search $newsearch$NL"
184	fi
185	for n in $newns; do
186		newconf="${newconf}nameserver $n$NL"
187	done
188
189	# Now add anything we don't care about such as sortlist and options
190	stuff="$($list_resolv | keys_remove nameserver domain search)"
191	if [ -n "$stuff" ]; then
192		newconf="$newconf$stuff$NL"
193	fi
194
195	# Append any user defined ones
196	if [ -n "$resolv_conf_options" ]; then
197		newconf="${newconf}options $resolv_conf_options$NL"
198	fi
199	if [ -n "$resolv_conf_sortlist" ]; then
200		newconf="${newconf}sortlist $resolv_conf_sortlist$NL"
201	fi
202
203	if [ -n "$resolv_conf_tail" ]; then
204		newconf="$newconf$resolv_conf_tail$NL"
205	fi
206	;;
207esac
208
209# Check if the file has actually changed or not
210if [ -e "$resolv_conf" ]; then
211	[ "$(cat "$resolv_conf")" = "$(printf %s "$newconf")" ] && exit 0
212fi
213
214# Change is good.
215# If the old file does not have our signature, back it up.
216# If the new file just has our signature, restore the backup.
217if $backup; then
218	if [ "$newconf" = "$signature$NL" ]; then
219		if [ -e "$resolv_conf.bak" ]; then
220			newconf="$(cat "$resolv_conf.bak")"
221		fi
222	elif [ -e "$resolv_conf" ]; then
223		read line <"$resolv_conf"
224		if [ "$line" != "$signature" ]; then
225			cp "$resolv_conf" "$resolv_conf.bak"
226		fi
227	fi
228fi
229
230# Create our resolv.conf now
231(umask 022; echo "$newconf" >"$resolv_conf")
232eval $libc_restart
233
234retval=0
235# Notify users of the resolver
236for script in "$LIBEXECDIR"/libc.d/*; do
237	if [ -f "$script" ]; then
238		if [ -x "$script" ]; then
239			"$script" "$@"
240		else
241			(. "$script")
242		fi
243		retval=$(($retval + $?))
244	fi
245done
246exit $retval
247