mmap'ing /dev/null

[Jamie Gennis]

Hi,   I'm new to the hurd and have been browsing around the source tree trying to become familiar with how things work in there.  I came across an "/* XXX should work! */" in trans/null.c's S_io_map() and thought this might be a good place to start coding something.  However, I'm not sure what the behavior for mmap'ing /dev/null should be, and Marcus said to ask here.   Thanks, Jamie