Test: child has pipe to parent, opens conf. file and write back
over pipe.

Recheck xattr on each read in case status changes?

Think about X11 copy and paste. Look at Xmon?

Enable log and other modes and also boot-time configuration.   

Ensure we did not break capabilities; see ...set_creds for an
example of where we needed to call a capability hook.

Benchmark vs. vanilla kernel
