support to check selinux label

Signed-off-by: ningmingxiao <ning.mingxiao@zte.com.cn>

Author: ningmingxiao

go-selinux/selinux.go

@@ -221,6 +221,19 @@ func ReserveLabel(label string) {
 	reserveLabel(label)
 }
 
+// CheckLabel check the MLS/MCS level component of the specified label
+func CheckLabel(mcs string) error {
+	if mcs == "" {
+		return nil
+	}
+	state.Lock()
+	defer state.Unlock()
+	if state.mcsList[mcs] {
+		return ErrMCSAlreadyExists
+	}
+	return nil
+}
+
 // MLSEnabled checks if MLS is enabled.
 func MLSEnabled() bool {
 	return isMLSEnabled()