This has been requested some while ago in ID: 973781 already.
I am able to read out the wrapper.logfile property through WrapperManager.getProperties().
However, when some rollmode is enabled, the current Logfile name is not obvious. I can't see any way of getting out the current logfile name with the existing API other than by guessing the name.
Something like WrapperManager.getLogfile():File would be useful.