Improve s6-rc rc.d script

* Deduplicate path literals
	* Pass live directory to s6-rc invocations

Changes #31

roles/s6-rc/templates/s6-rc.j2

@@ -5,6 +5,13 @@
 # REQUIRE: NETWORKING daemon
 # KEYWORD: shutdown
 
+etc_dir="{{ s6_etc_dir }}"
+scan_dir="{{ s6_scan_dir }}"
+live_dir="{{ s6_live_dir }}"
+
+EX_UNAVAILABLE=69
+EX_CONFIG=78
+
 . /etc/rc.subr
 
 export PATH="$PATH:/usr/local/bin:/usr/local/sbin"
@@ -27,7 +34,7 @@ s6_wait()
 {
 	local i=0
 
-	while ! s6-svscanctl -z /run/service 2>/dev/null; do
+	while ! s6-svscanctl -z "$scan_dir" 2>/dev/null; do
 		if [ $i -ge $s6_timeout ]; then
 			echo "Timeout waiting for s6-svscan." >&2
 			return 1
@@ -48,19 +55,19 @@ s6_wait()
 
 s6_rc_init()
 {
-	if [ ! -e /run/s6-rc ]; then
+	if [ ! -e "$live_dir" ]; then
-		s6-rc-init /run/service
+		s6-rc-init -l "$live_dir" "$scan_dir"
 	fi
 }
 
 s6_rc_up()
 {
-	s6-rc -v 2 -u -t $up_timeout change enabled
+	s6-rc -l "$live_dir" -v 2 -u -t "$up_timeout" change enabled
 }
 
 s6_rc_down()
 {
-	s6-rc -v 2 -d -a -t $down_timeout change
+	s6-rc -l "$live_dir" -v 2 -d -a -t "$down_timeout" change
 }
 
 s6_rc_start()
@@ -82,16 +89,26 @@ s6_rc_reload()
 {
 	local uuid="$(uuidgen)"
 
-	cd /etc/s6-rc
+	cd "$etc_dir"
-	echo "Compiling new s6-rc service database."
+	echo "Compiling the s6-rc service definitions into a services database: $etc_dir/service -> $etc_dir/.compiled.$uuid."
-	s6-rc-compile -v 2 ".compiled.$uuid" service
+	if ! s6-rc-compile -v 2 ".compiled.$uuid" service; then
+		echo "Failed to compile the service definitions into a services database." >&2
+		return $EX_CONFIG
+	fi
 
-	if s6-rc-update -v 2 -t $update_timeout "/etc/s6-rc/.compiled.$uuid"; then
+	echo "Updating the running s6-rc service manager to the latest compiled services database: $etc_dir/.compiled.$uuid."
+	if s6-rc-update -l "$live_dir" -v 2 -t $update_timeout "$etc_dir/.compiled.$uuid"; then
+		echo "Marking the running services database as selected default configuration: .compiled.$uuid -> compiled."
 		ln -shf ".compiled.$uuid" compiled
-		echo "Updated s6-rc service database."
 
-		echo "Deleting old service databases."
+		echo "Deleting stale services databases."
-		find -s . -mindepth 1 -maxdepth 1 -type d -name '.compiled.*' -not -name ".compiled.$uuid" -print0 | xargs -0 rm -r
+		if ! find -s . -mindepth 1 -maxdepth 1 -type d -name '.compiled.*' -not -name ".compiled.$uuid" -print0 | xargs -0 rm -r; then
+			echo "Failed to delete stale services databases." >&2
+			return $EX_CONFIG
+		fi
+	else
+		echo "Failed to update the running s6-rc manager to the latest service database." >&2
+		return $EX_CONFIG
 	fi
 }
 
@@ -99,19 +116,20 @@ s6_rc_status()
 {
 	local result=0
 
-	if s6-svscanctl -z /run/service 2>/dev/null; then
+	# Check if s6-svscan is responsive by asking it to invoke its reaper (almost a NOP)
-		echo "The s6-svscan supervisor is responsible."
+	if s6-svscanctl -z "$scan_dir" 2>/dev/null; then
+		echo "The s6-svscan supervisor is responsive."
 	else
 		echo "The s6-svscan supervisor is unavailable."
 		result=1
 	fi
 
-	if [ -e /run/s6-rc ]; then
+	if [ -e "$live_dir" ]; then
-		echo "The s6-rc service manager is initialized."
+		echo "The s6-rc service manager has been initialized."
 
 		echo
 		echo "These services are currently active:"
-		s6-rc -a list
+		s6-rc -l "$live_dir" -a list
 	else
 		echo "The s6-rc service manager is uninitalized."
 		result=1