Add ValidURN(). Be sure to unlink tmp file on failed create instance.

www/aptui/instance_defs.php

@@ -238,6 +238,7 @@ class Instance
 	$retval = SUEXEC($uid, $pid,
 			 "webcreate_instance $options -u $uuid $xmlname",
 			 SUEXEC_ACTION_IGNORE);
+	unlink($xmlname);
 
 	if ($retval != 0) {
 	    if ($retval < 0) {
@@ -258,8 +259,6 @@ class Instance
 	    }
 	    return null;
 	}
-	unlink($xmlname);
-
 	$instance = Instance::Lookup($uuid);
 	if (!$instance) {
 	    $errors["error"] = "Transient error(5); please try again later.";
@@ -347,6 +346,13 @@ class Instance
         }
         return array();
     }
+    function ValidURN($urn)
+    {
+        if (preg_match("/^[^+]*\+([^+]+)\+([^+]+)\+(.+)$/", $urn)) {
+            return true;
+        }
+        return false;
+    }
 
     function SetExtensionReason($reason)
     {