#!/bin/sh

### BEGIN INIT INFO
# Provides:          isc-dhcp-server
# Required-Start:    $remote_fs $network $syslog
# Required-Stop:     $remote_fs $network $syslog
# Should-Start:      $local_fs slapd $named
# Should-Stop:       $local_fs slapd
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: DHCP server
# Description:       Dynamic Host Configuration Protocol Server
### END INIT INFO

PATH=/sbin:/bin:/usr/sbin:/usr/bin

test -f /usr/sbin/dhcpd || exit 0

DHCPD_DEFAULT="${DHCPD_DEFAULT:-/etc/default/isc-dhcp-server}"

# It is not safe to start if we don't have a default configuration...
if [ ! -f "$DHCPD_DEFAULT" ]; then
        echo "$DHCPD_DEFAULT does not exist! - Aborting..."
        if [ "$DHCPD_DEFAULT" = "/etc/default/isc-dhcp-server" ]; then
                echo "Run 'dpkg-reconfigure isc-dhcp-server' to fix the problem."
        fi
        exit 0
fi

. /lib/lsb/init-functions

# Read init script configuration
[ -f "$DHCPD_DEFAULT" ] && . "$DHCPD_DEFAULT"

NAME4=dhcpd
NAME6=dhcpd6

DESC4="ISC DHCPv4 server"
DESC6="ISC DHCPv6 server"

# use already specified config file or fallback to defaults
DHCPDv4_CONF=${DHCPDv4_CONF:-/etc/dhcp/dhcpd.conf}
DHCPDv6_CONF=${DHCPDv6_CONF:-/etc/dhcp/dhcpd6.conf}

# try to read pid file name from config file or fallback to defaults
if [ -z "$DHCPDv4_PID" ]; then
        DHCPDv4_PID=$(sed -n -e 's/^[ \t]*pid-file-name[ \t]*"\(.*\)"[ \t]*;.*$/\1/p' < "$DHCPDv4_CONF" 2>/dev/null | head -n 1)
fi
if [ -z "$DHCPDv6_PID" ]; then
        DHCPDv6_PID=$(sed -n -e 's/^[ \t]*dhcpv6-pid-file-name[ \t]*"\(.*\)"[ \t]*;.*$/\1/p' < "$DHCPDv6_CONF" 2>/dev/null | head -n 1)
fi
DHCPDv4_PID="${DHCPDv4_PID:-/var/run/dhcpd.pid}"
DHCPDv6_PID="${DHCPDv6_PID:-/var/run/dhcpd6.pid}"

test_config()
{
        VERSION="$1"
        CONF="$2"

        if ! /usr/sbin/dhcpd -t $VERSION -q -cf "$CONF" > /dev/null 2>&1; then
                echo "dhcpd self-test failed. Please fix $CONF."
                echo "The error was: "
                /usr/sbin/dhcpd -t $VERSION -cf "$CONF"
                exit 1
        fi
}

check_status()
{
        OPTION="$1"
        PIDFILE="$2"
        NAME="$3"

        if [ ! -r "$PIDFILE" ]; then
                test "$OPTION" != -v || echo "$NAME is not running."
                return 3
        fi

        if read pid < "$PIDFILE" && ps -p "$pid" > /dev/null 2>&1; then
                test "$OPTION" != -v || echo "$NAME is running."
                return 0
        else
                test "$OPTION" != -v || echo "$NAME is not running but $PIDFILE exists."
                return 1
        fi
}

start_daemon()
{
        VERSION="$1"
        CONF="$2"
        NAME="$3"
        PIDFILE="$4"
        DESC="$5"

        shift 5
        INTERFACES="$*"

        test_config "$VERSION" "$CONF"
        log_daemon_msg "Starting $DESC" "$NAME"

        if [ -e "$PIDFILE" ]; then
                log_failure_msg "dhcpd service already running (pid file $PIDFILE currenty exists)"
                exit 1
        fi

        touch /var/lib/dhcp/$NAME.leases

        start-stop-daemon --start --quiet --pidfile $PIDFILE \
                --exec /usr/sbin/dhcpd -- $VERSION -q -cf $CONF $INTERFACES
        sleep 2

        if check_status -q $PIDFILE $NAME; then
                log_end_msg 0
        else
                log_failure_msg "check syslog for diagnostics."
                log_end_msg 1
                exit 1
        fi
}

stop_daemon()
{
        if check_status -q $DHCPDv4_PID $NAME4; then
                log_daemon_msg "Stopping $DESC4" "$NAME4"
                start-stop-daemon --stop --quiet --pidfile $DHCPDv4_PID
                log_end_msg $?
                rm -f "$DHCPDv4_PID"
        fi

        if check_status -q $DHCPDv6_PID $NAME6; then
                log_daemon_msg "Stopping $DESC6" "$NAME6"
                start-stop-daemon --stop --quiet --pidfile $DHCPDv6_PID
                log_end_msg $?
                rm -f "$DHCPDv6_PID"
        fi
}
wait_for_dhcpd()
{
        while [ ! -f "/var/run/dhcpcd.pid" ]; do
                echo "waiting for dhcpd to start"
                sleep 1
        done
        sleep 10
}

case "$1" in
        start)
                wait_for_dhcpd
                if test -n "$INTERFACES" -a -z "$INTERFACESv4"; then
                        echo "DHCPv4 interfaces are no longer set by the INTERFACES variable in" >&2
                        echo "/etc/default/isc-dhcp-server.  Please use INTERFACESv4 instead." >&2
                        echo "Migrating automatically for now, but this will go away in the future." >&2
                        INTERFACESv4="$INTERFACES"
                fi
                if test -n "$INTERFACESv4"; then
                        echo "Launching IPv4 server only."
                        start_daemon "-4" "$DHCPDv4_CONF" "$NAME4" \
                                "$DHCPDv4_PID" "$DESC4" "$INTERFACESv4"
                fi
                if test -n "$INTERFACESv6"; then
                        echo "Launching IPv6 server only."
                        start_daemon "-6" "$DHCPDv6_CONF" "$NAME6" \
                                "$DHCPDv6_PID" "$DESC6" "$INTERFACESv6"
                fi
                if test -z "$INTERFACESv4" -a -z "$INTERFACESv6"; then
                        echo "Launching both IPv4 and IPv6 servers (please configure INTERFACES in /etc/default/isc-dhcp-server if you only want one or the other)."
                        start_daemon "-4" "$DHCPDv4_CONF" "$NAME4" \
                                "$DHCPDv4_PID" "$DESC4" ""
                        start_daemon "-6" "$DHCPDv6_CONF" "$NAME6" \
                                "$DHCPDv6_PID" "$DESC6" ""
                fi
                ;;
        stop)
                stop_daemon
                ;;
        restart | force-reload)
                $0 stop
                sleep 2
                $0 start
                if [ "$?" != "0" ]; then
                        exit 1
                fi
               ;;
        status)
                if test -n "$INTERFACES" -a -z "$INTERFACESv4"; then
                        INTERFACESv4="$INTERFACES"
                fi
                if test -n "$INTERFACESv4"; then
                        echo -n "Status of $DESC4: "
                        check_status -v $DHCPDv4_PID $NAME4 || exit $?
                fi
                if test -n "$INTERFACESv6"; then
                        echo -n "Status of $DESC6: "
                        check_status -v $DHCPDv6_PID $NAME6 || exit $?
                fi
                ;;
        *)
                echo "Usage: $0 {start|stop|restart|force-reload|status}"
                exit 1
esac

exit 0