main/xen: fix race in xendomains init.d script

the gnu screen would show files in SCREENDIR before its ready to accept
connections. so starting domains failed

1 files changed, 55 insertions, 35 deletions

diff --git a/main/xen/xendomains.initd b/main/xen/xendomains.initd
index e6751eeeaa..dd5a924f66 100644
--- a/main/xen/xendomains.initd
+++ b/main/xen/xendomains.initd
@@ -37,26 +37,16 @@ set_screen_cmd() {
 	screen_cmd="screen -c ${SCREENRC:-/dev/null} -q -r ${SCREEN_NAME:=xen} -X"
 }
 
-dir_is_empty() {
-	local dir=$1
-	set -- "$dir"/*
-	test "$1" = "$dir/*"
-}
-
 wait_screen() {
-	while dir_is_empty "$SCREENDIR"; do
+	while ! ${screen_cmd} dettach; do
 		sleep 0.1
 	done
 }
 
-start() {
+init_screen() {
 	set_screen_cmd
-	checkpath --directory --mode 755 /var/run/xen
-
-	einfo "Starting Xen domains from ${AUTODIR:=/etc/xen/auto}"
-	if using_screen ; then
-		ebegin "Creating screen session to hold domain consoles"
-		(  screen -c ${SCREENRC:-/dev/null} -d -m -S ${SCREEN_NAME} -t dom0 \
+	ebegin "Creating screen session to hold domain consoles"
+	(  screen -c ${SCREENRC:-/dev/null} -d -m -S ${SCREEN_NAME} -t dom0 \
 		&& wait_screen \
 		&& ${screen_cmd} zombie dr \
 		&& logrotate -f /etc/xen/xen-consoles.logrotate \
@@ -64,13 +54,54 @@ start() {
 		&& ${screen_cmd} logfile flush ${SCREEN_LOG_INTERVAL:-1} \
 		&& ${screen_cmd} log on \
 		&& ${screen_cmd} deflog on ) >/dev/null
-		if [ $? -ne 0 ] ; then
-			eend 1
-			return 1
-		else
-			eend
-		fi
+	eend $?
+}
+
+startdom_screen() {
+	${screen_cmd} screen -t ${1} xl create ${2} -c
+}
+
+close_screen() {
+	set_screen_cmd
+	if ${screen_cmd} sleep 0 >/dev/null 2>&1 ; then
+		ebegin "Closing screen session ${SCREEN_NAME}"
+		${screen_cmd} quit
+		eend $?
+	else
+		eend 0
 	fi
+}
+
+startdom_noconsole() {
+	xl create --quiet ${2}
+}
+
+
+set_dom_cmd() {
+	if using_screen; then
+		: ${XENDOMAINS_CONSOLE:=screen}
+	fi
+	case "$XENDOMAINS_CONSOLE" in
+	screen)
+		initconsole=init_screen
+		startdom=startdom_screen
+		closeconsole=close_screen
+		;;
+	*)
+		initconsole=
+		startdom=startdom_noconsole
+		closeconsole=
+	esac
+}
+
+start() {
+	set_dom_cmd
+	checkpath --directory --mode 755 /var/run/xen
+
+	einfo "Starting Xen domains from ${AUTODIR:=/etc/xen/auto}"
+
+	$initconsole
+
 	# Create all domains with config files in AUTODIR.
 	want_usleep=
 	for dom in $(ls "${AUTODIR:=/etc/xen/auto}/"* 2>/dev/null | sort); do
@@ -82,11 +113,7 @@ start() {
 				want_usleep=1
 			fi
 			ebegin "  Starting domain ${name}"
-			if using_screen ; then
-				${screen_cmd} screen -t ${name} xl create ${dom} -c
-			else
-				xl create --quiet ${dom}
-			fi
+			$startdom ${name} ${dom}
 			eend $?
 		else
 			einfo "  Not starting domain ${name} - already running"
@@ -95,7 +122,7 @@ start() {
 }
 
 stop() {
-	set_screen_cmd
+	set_dom_cmd
 
 	einfo "Shutting down Xen domains from ${AUTODIR:=/etc/xen/auto}"
 	# Stop all domains with config files in AUTODIR.
@@ -126,15 +153,8 @@ stop() {
 			fi
 		done
 	fi
-	if using_screen ; then
-		if ${screen_cmd} sleep 0 >/dev/null 2>&1 ; then
-			ebegin "Closing screen session ${SCREEN_NAME}"
-			${screen_cmd} quit
-			eend $?
-		else
-			eend 0
-		fi
-	fi
+
+	$closeconsole
 }
 
 status() {