#!/bin/sh
# Copyright (c) 2007-2009 Roy Marples
# All rights reserved

# named subscriber for resolvconf

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
#       copyright notice, this list of conditions and the following
#       disclaimer in the documentation and/or other materials provided
#       with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

[ -f "/etc"/resolvconf.conf ] || exit 0
. "/etc/resolvconf.conf" || exit 1
[ -n "$named_zones" -a -n "$named_options" -a \
	-d "${named_zones%/*}" -a -d "${named_options%/*}" ] || exit 0
[ -z "$RESOLVCONF" ] && eval "$(/sbin/resolvconf -v)"

: ${named_service:=bind}
: ${named_restart:=/sbin/service ${named_service} condreload}

list_own_zones()
{
    find "${named_zones%/*}" \
	-type f \( -name '*.conf' -a \! -name "${named_zones##*/}" \) \
	-exec sed -n 's/zone[[:space:]]\+"\([^"]\+\)\".*/\1/p' '{}' \+ |grep -v 'in-addr\.arpa$'|tr '\n' ' '
}

ownzones=" $(list_own_zones) "

newoptions="# Generated by resolvconf\n"
newzones="$newoptions"

forward=
for n in $NAMESERVERS; do
	case "$forward" in
	*"\n\t$n;"*);;
	*) forward="$forward\n\t$n;";;
	esac
done
if [ -n "$forward" ]; then
	newoptions="${newoptions}forward first;\nforwarders {$forward\n};\n"
fi

for d in $DOMAINS; do
	zone="${d%%:*}"
	[ -n "${ownzones## *$zone* }" ] || continue
	newzones="${newzones}zone \"$zone\" {\n"
	newzones="$newzones\ttype forward;\n"
	newzones="$newzones\tforward first;\n\tforwarders {\n"
	ns="${d#*:}"
	while [ -n "$ns" ]; do
		newzones="$newzones\t\t${ns%%,*};\n"
		[ "$ns" = "${ns#*,}" ] && break
		ns="${ns#*,}"
	done
	newzones="$newzones\t};\n};\n"
done

# No point in changing files or reloading bind if the end result has not
# changed
changed=false
if [ -n "$named_options" ]; then
	if [ ! -f "$named_options" ] || \
		[ "$(cat "$named_options")" != "$(printf "$newoptions")" ]
	then
		printf "$newoptions" >"$named_options"
		changed=true
	fi
fi
if [ -n "$named_zones" ]; then
	if [ ! -f "$named_zones" ] || \
		[ "$(cat "$named_zones")" != "$(printf "$newzones")" ]
	then
		printf "$newzones" >"$named_zones"
		changed=true
	fi
fi

if $changed; then
	eval $named_restart
fi
exit 0
