tcmu-handler.xml

<node>
  <interface name="org.kernel.TCMUService1">
    <property name="ConfigDesc" type="s" access="read"/>
    <!--
	CheckConfig:

The creation of a TCMU device is decoupled from the discovery and
use by its backing handler, and there's no good way for errors in
the handler-specific configstring to be visible to the user when
creating the device.
This method lets tools that are creating TCMU devices check
that the configstring is valid before the device has been created.
    -->
    <method name="CheckConfig">
      <arg type="s" name="configstr" direction="in"/>
      <arg type="b" name="is_valid" direction="out"/>
      <arg type="s" name="message" direction="out"/>
    </method>
  </interface>
</node>