anchor.diff:        httpListenAddress = mkOption {
   	default = null;
   	example = "myserver:8080";
  -        description = "ip:port or port for virtuoso HTTP server to listen on.";
  +        description = "ip:port or port for Virtuoso HTTP server to listen on.";
         };
   
  +      dirsAllowed = mkOption {
  +	default = null;
  +	example = "/www, /home/";
  +        description = "A list of directories Virtuoso is allowed to access";
  +      };
       };
   
     };
  
positive.code: 
        config = mkOption {
          default = "";
          description = "Extra options to put into virtuoso configuration file.";
        };
  
        listenAddress = mkOption {
  
negative.code:       [Parameters]
        ServerPort=${cfg.listenAddress}
        RunAs=${virtuosoUser}
        ${optionalString (cfg.dirsAllowed != null) "DirsAllowed=${cfg.dirsAllowed}"}
  
        [HTTPServer]
        ${optionalString (cfg.httpListenAddress != null) "ServerPort=${cfg.httpListenAddress}"}
  