#!/bin/bash
set -e
base=/var/named
conf=$base/conf
etcfile=/etc/named/zones-rgc

check=true
install=false
hostdelg=false
hostzone=false
progress=true
usage=true

while [ $# -gt 0 ]
do
	case "$1" in
	-f)	usage=false; check=false; install=true ;;
	-y)	usage=false; check=true; install=true ;;
	-n)	usage=false; check=true; install=false ;;
	-h)	hostdelg=true; hostzone=false ;;
	-z)	hostdelg=true; hostzone=true ;;
	-q)	progress=false ;;
	*)	echo >&2 "$0: usage: $0 [-y|-f] [-h|-z] [-q]"; exit 3 ;;
	esac
	shift
done

if $usage
then
	cat <<END >&2
usage: named-conf-regen -f|-y|-n [-h|-z]
operation modes:
 -f   install without checking  } but you must then
 -y   check and install         }  ndc reload
 -n   check only
additional options:
 -h   check output from host -C
 -z   check output from host -C and host -val
END
	exit 1
fi

beginfile () {
	if $install
	then
		exec >$conf/$1.new
	else
		exec >/dev/null
	fi
	currentfile=$1
}

endfile () {
	exec >/dev/null
	files="$files $currentfile"
}

installfiles () {
	if $install
	then
		cd $conf
		for f in $files
		do
			mv -f $f.new $f
		done
	fi
}

warnings=0

warning () {
	echo >&2 "$zone $style: $*"
	warnings=$[$warnings+1]
}

equlines () {
	if [ "x`echo \" $2\" | wc -l`" != "x`echo \" $3\" | wc -l`" ]
	then
		warning "$1 >$2|$3<"
	fi
}

checkhostout () {
	set +e
	hostout="`host $1 \"$zone\" 2>&1 >/dev/null $2 | egrep -v \
'^ \!\!\! .* SOA primary .* is not advertised via NS$'`"
	set -e
	if [ "x$hostout" = x ]; then return; fi
	if $hostfirstwarn
	then
		warning "warnings from host:"
		hostfirstwarn=false
	fi
	echo >&2 "$hostout"
}

progress () {
	if $progress
	then
		echo -n "$zone $style                    " >&2
		echo -ne '\r' >&2
	fi
}

cd $base/primary
zones="*_db"

beginfile primary.zones
for f in $zones
do
	zone="`echo $f | sed -e 's/_db$//'`"
	cat <<END
zone "$zone" {
	type master;
	file "primary/$f";
};
END
done
endfile

myname=''

beginfile secondary.zones
exec <$etcfile
while read style zone servers
do
	names=''
	case "$style" in
	myname)
		myname=$zone
		continue
		;;
	secondary)
		progress
		file="slave/$zone"
		if $check
		then
			rectype=SOA
			set -e; soa="`host -t soa $zone.`"; set +e
			soaname="`echo \" $soa\" | expand | sed -e '
				s/^ [^ ][^ ]*  *SOA  *//; s/ .*$//; q
			'`"
			equlines SOA "$soaname" ''
		fi
		;;
	backup|unoff)
		progress
		rectype=NS
		file="slave/$zone"
		;;
	'#'|'')
		continue
		;;
	*)
		echo >&2 "$etcfile: $style"
		exit 3
	esac

	if $check
	then
		set -e; ns="`host -t ns $zone.`"; set +e
		nsnames="`echo \" $ns\" | expand | tr A-Z a-z | sed -n '
			1s/^ //
			s/^[^ ][^ ]*  *ns  *\([0-9a-z][-.0-9a-z]*\)$/\1/p
		'`"
		equlines NS "$nsnames" "$ns"
		nsnames="`echo $nsnames | tr '
' ' '`"

		if [ "x$myname" != x ]
		then
			meadvert=false
			for ns in $nsnames
			do
				if [ "x$myname" = "x$ns" ]
				then
					meadvert=true
				fi
			done
		fi

		case "$style" in
		secondary)	names="$soaname"	;;
		unoff|backup)	names="$nsnames"	;;
		esac

		case "$style" in
		secondary|backup)
			if [ $meadvert = false ]
			then
				warning "$myname unlisted NS $nsnames"
			fi
			;;
		unoff)
			if $meadvert = false
			then
				warning "$myname advertised NS $nsnames"
			fi
			;;
		esac

		addrs=''
		for ns in $names
		do
			set -e; a="`host -t a \"$ns\".`"; set +e
			taddrs="`echo \" $a\" | expand | sed -n '
				 1s/^ //
				s/^[^ ][^ ]*  *A  *\([0-9][.0-9]*\)/\1/p
			'`"
			equlines "A $ns" "$a" "$taddrs"
			addrs="$addrs $taddrs"
		done
	fi

	cat <<END
zone "$zone" {
	type slave;
	file "$file";
	masters {
END
	for server in $servers
	do
		echo "		$server;"
		if $check
		then
			notfound=true
			for addr in $addrs
			do
				if [ "x$addr" = "x$server" ]
				then
					notfound=false
				fi
			done
			if $notfound
			then
 warning "server $server? but $rectype $names" $addrs
			fi
		fi
	done
	cat <<END
	};
};
END
	hostfirstwarn=true
	if $hostdelg
	then
		checkhostout -C
	fi
	if $hostzone
	then
		checkhostout -val localhost
	fi
done
endfile

if [ $warnings != 0 ]
then
	echo >&2 "$warnings warnings                                        "
fi

installfiles