systemd: Add support for 'Listening' state

Currently the systemd status code is not able to parse the status of
listening socket units (`Active: active (listening)`). This causes
the checkLibvirtServiceRunning preflight check to unexpectedly fail on
systems using socket activation.
This commit should add the missing parsing, and fix this issue

This fixes #1705

pkg/crc/preflight/preflight_checks_linux.go

@@ -223,12 +223,19 @@ func checkLibvirtServiceRunning() error {
 	libvirtSystemdUnits := []string{"virtqemud.socket", "libvirtd.socket", "virtqemud.service", "libvirtd.service"}
 	for _, unit := range libvirtSystemdUnits {
 		status, err := sd.Status(unit)
-		if err == nil && status == states.Running {
-			logging.Debugf("%s is running", unit)
-			return nil
+		if err == nil {
+			switch status {
+			case states.Running:
+				logging.Debugf("%s is running", unit)
+				return nil
+			case states.Listening:
+				logging.Debugf("%s is listening", unit)
+				return nil
+			default:
+				logging.Debugf("%s is neither running nor listening", unit)
+			}
 		}
 
-		logging.Debugf("%s is not running", unit)
 	}
 
 	logging.Warnf("No active (running) libvirtd systemd unit could be found - make sure one of libvirt systemd units is enabled so that it's autostarted at boot time.")

pkg/crc/systemd/states/state.go

@@ -9,6 +9,7 @@ type State int
 const (
 	Unknown State = iota
 	Running
+	Listening
 	Stopped
 	NotFound
 	Error
@@ -17,6 +18,7 @@ const (
 var states = []string{
 	"unknown",
 	"active (running)",
+	"active (listening)",
 	"inactive (dead)",
 	"could not be found",
 	"error",
@@ -33,6 +35,9 @@ func Compare(input string) State {
 	if strings.Contains(input, states[Running]) {
 		return Running
 	}
+	if strings.Contains(input, states[Listening]) {
+		return Listening
+	}
 	if strings.Contains(input, states[Stopped]) {
 		return Stopped
 	}