linux_base and devfs on 5.x: what to do about character devices

[Robert Watson]

It was recently brought to my attention that some users of FreeBSD have
somewhat populated /compat/linux/dev trees with hard-coded character
device entries in there.  Often, this seems to occur on upgrded 4.x
machines running on 5.x The problem with this is that we're in the throes
of gradually moving away from hard-coded major device numbers, so those
entries will grow increasingly inaccurate over time.  I'd like to find out
a bit more about how /dev is managed in linux compat land, what ports do
special things with it, and how we can make sure that the linux compat
code runs without any hitches on 5.2-RELEASE when we go -STABLE.

>From a 5.x technical perspective, any ideal solution would avoid any
character device nodes anywhere outside of /dev, so that would mean
avoiding any entries in a linux-compat-specific dev, or making sure they
are symlinks to the real /dev, or the like.  Feedback very welcome!

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at fledge.watson.org      Network Associates Laboratories