code: public function chmod($strFile, $varMode)
  	{
  		$this->validate($strFile);
  
  		return chmod($this->strRootDir . '/' . $strFile, $varMode);
  	}
docs: Change the file mode
  
  @param string $strFile The file name
  @param mixed  $varMode The new file mode
  
  @return boolean True if the operation was successful