fix temporary file creation

lib/helper.php

@@ -425,8 +425,11 @@ class OC_Helper {
 	 * temporary files are automatically cleaned up after the script is finished
 	 */
 	public static function tmpFile($postfix=''){
-		$file=tempnam(get_temp_dir(),'OC_TMP_').$postfix;
+		$file=get_temp_dir().'/'.md5(time().rand()).$postfix;
+		$fh=fopen($file,'w');
+		fclose($fh);
 		self::$tmpFiles[]=$file;
+		error_log($file);
 		return $file;
 	}
 	
@@ -436,6 +439,7 @@ class OC_Helper {
 	public static function cleanTmp(){
 		foreach(self::$tmpFiles as $file){
 			if(file_exists($file)){
+				error_log("clean $file");
 				unlink($file);
 			}
 		}