Re: FreeBSD devfs support on NetBSD 5.0

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> [...], but if you do want to see new devices pop up in a chroot area
> then you need to come up with a new security model because your
> current one is broken by its design :-))

Hardly.  You're assuming chroots are used only for jailing things like
NTP.  That's far from its only use; for example, I've used chroots for
"play areas", areas whwere I can, for example, test a "build and
isntall of the world" without risking my current system.  In an
environment like that, I pretty much want /dev to be as much like the
real thing as feasiable.

> I think PUFFS is _WAY_ too may layers -- devfs should be a kernel
> level implementation.

Eventually, perhaps.  But for a first cut at it, puffs strikes me as
perfect; it's a good filesystem development framework in many respects.

The major thing I think this needs is a union layer that doesn't copy
up on changes, but rather applies modifications to what's in the lower
layer.  In particular, something like "chmod 666 /dev/uk0" needs to
result in uk0 being left in the lower layer in all respects but
permissions, rather than an upper-layer vnode being created which
completely hides the lower-layer one.  This is necessary to make things
disappear correctly on detach....

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