Type of automation done in white box testing

White box testing can be performed at various levels like unit, integration and system level.

I have following queries regarding white box testing:

1) What type of automation comes under white box testing at above given testing levels?

2) What are some of tools used for white box testing automation?

3) Is selenium can also be used for white box automation testing?

4) Does having black box automation testing info gives any benefit in doing white box automation testing?

Thanks...