Add djbdns backend

Add docs and basic tests
Update config sample file and support matrix
Change-Id: I709cea4e321f6bbee3b0f9f718fa6a9836af3ca5

2 files changed, 154 insertions, 0 deletions

diff --git a/contrib/djbdns/tinydns.init b/contrib/djbdns/tinydns.init
new file mode 100755
index 00000000..7bcbb477
--- /dev/null
+++ b/contrib/djbdns/tinydns.init
@@ -0,0 +1,110 @@
+#! /bin/bash
+### BEGIN INIT INFO
+# Provides:          tinydns
+# Required-Start:    $local_fs $remote_fs $network
+# Required-Stop:     $local_fs $remote_fs $network
+# Should-Start:      $syslog
+# Should-Stop:       $syslog
+# Default-Start:     2 3 4 5
+# Default-Stop:      0 1 6
+# Short-Description: tinydns daemon processes
+# Description:       Start the TinyDNS resolver
+### END INIT INFO
+
+# Documentation
+#  man tinydns
+
+# Load the VERBOSE setting and other rcS variables
+. /lib/init/vars.sh
+
+# Define LSB log_* functions.
+. /lib/lsb/init-functions
+
+NAME=tinydns
+DAEMON=/usr/bin/$NAME
+DAEMON_USER=djbdns
+DESC="the tinydns daemon"
+ROOTDIR=/var/lib/djbdns
+PATH=/sbin:/bin:/usr/sbin:/usr/bin
+LAUNCHER=/usr/bin/envuidgid
+LAUNCHER_ARGS="$DAEMON_USER envdir ./env softlimit -d300000 $DAEMON"
+
+PIDFILE=/run/$NAME.pid
+
+# Exit if executable is not installed
+[ -x "$DAEMON" ] || exit 0
+
+set -x
+
+case "$1" in
+  start)
+	if [ ! -d "$ROOTDIR" ]; then
+		log_action_msg "Not starting $DESC: $ROOTDIR is missing."
+		exit 0
+	fi
+
+	log_action_begin_msg "Starting $DESC"
+
+	if start-stop-daemon --stop --signal 0 --quiet --pidfile $PIDFILE --exec $DAEMON; then
+		log_action_end_msg 0 "already running"
+	else
+		if start-stop-daemon --start --verbose --make-pidfile --chdir $ROOTDIR --pidfile $PIDFILE  --exec $LAUNCHER -- $LAUNCHER_ARGS
+		then
+			log_action_end_msg 0
+		else
+			log_action_end_msg 1
+			exit 1
+		fi
+	fi
+	;;
+  stop)
+	log_action_begin_msg "Stopping $DESC"
+	pid=$(cat $PIDFILE 2>/dev/null) || true
+	if test ! -f $PIDFILE -o -z "$pid"; then
+		log_action_end_msg 0 "not running - there is no $PIDFILE"
+		exit 0
+	fi
+
+	if start-stop-daemon --stop --signal INT --quiet --pidfile $PIDFILE --exec $DAEMON; then
+		rm -f $PIDFILE
+	elif kill -0 $pid 2>/dev/null; then
+		log_action_end_msg 1 "Is $pid not $NAME?  Is $DAEMON a different binary now?"
+		exit 1
+	else
+		log_action_end_msg 1 "$DAEMON died: process $pid not running; or permission denied"
+		exit 1
+	fi
+	;;
+  reload)
+	echo "Not implemented, use restart"
+	exit 1
+	;;
+  restart|force-reload)
+	$0 stop
+	$0 start
+	;;
+  status)
+	if test ! -r $(dirname $PIDFILE); then
+		log_failure_msg "cannot read PID file $PIDFILE"
+		exit 4
+	fi
+	pid=$(cat $PIDFILE 2>/dev/null) || true
+	if test ! -f $PIDFILE -o -z "$pid"; then
+		log_failure_msg "$NAME is not running"
+		exit 3
+	fi
+	if ps "$pid" >/dev/null 2>&1; then
+		log_success_msg "$NAME is running"
+		exit 0
+	else
+		log_failure_msg "$NAME is not running"
+		exit 1
+	fi
+	;;
+  *)
+	log_action_msg "Usage: $0 {start|stop|restart|force-reload|status}" >&2
+	exit 1
+	;;
+esac
+
+exit 0
diff --git a/contrib/djbdns/tinydns.service b/contrib/djbdns/tinydns.service
new file mode 100644
index 00000000..2fcf9d2a
--- /dev/null
+++ b/contrib/djbdns/tinydns.service
@@ -0,0 +1,44 @@
+#
+# Replace /var/lib/djbdns if needed
+#
+
+[Unit]
+Description=tinydns DNS resolver
+Documentation=man:tinydns
+Documentation=https://cr.yp.to/djbdns.html
+After=network.target
+Requires=network.target
+Wants=network.target
+ConditionPathExists=/var/lib/djbdns
+
+[Service]
+Type=forking
+PIDFile=/run/tinydns.pid
+Environment="ROOT=/var/lib/djbdns"
+ExecStart=/usr/bin/tinydns
+ExecStop=-/sbin/start-stop-daemon --quiet --stop --retry=TERM/5/KILL/5 --pidfile /run/tinydns.pid
+TimeoutStopSec=30
+KillMode=mixed
+
+PermissionsStartOnly=true
+Restart=on-abnormal
+RestartSec=2s
+LimitNOFILE=65536
+
+WorkingDirectory=/var/lib/djbdns
+User=$ug_name
+Group=$ug_name
+
+# Hardening
+# CapabilityBoundingSet=CAP_NET_BIND_SERVICE CAP_CHOWN CAP_FOWNER
+NoNewPrivileges=yes
+PrivateDevices=yes
+PrivateTmp=yes
+ProtectHome=yes
+ProtectSystem=full
+# TODO: restrict ReadOnlyDirectories
+ReadOnlyDirectories=/
+ReadWriteDirectories=-/var/lib/djbdns
+
+[Install]
+WantedBy=multi-user.target