Re: Devfs, was Re: Migrating to larger numbers

Paul Jakma (paul@clubi.ie)
Thu, 10 Jun 1999 03:21:42 +0100 (IST)


On Tue, 8 Jun 1999, Matthew Kirkwood wrote:

On Tue, 8 Jun 1999, Paul Jakma wrote:

> devfs is a good thing. I and all the rest who have tried it and use it
> regularly think so.

And those of us who tried it and decided that it's the wrong solution to a
set of non-problems think otherwise.

imo it's a far cleaner and transparent way of doing things, which
solves one or two little problems along the way, (eg dynamic
devices).

> It's compatible, it's clean, it eliminates /dev admin maintenance.

What /dev admin maintenance? Perhaps my machines don't have enough disks,
but I have never needed to perform significant work in /dev.

ok /dev maintenance is not a regular thing. But when you have to do
it, it can be a pain. Eg permissions. With devfs you can specify that
certain classes of devices should have a certain permission, eg scsi
disks should be root:disk 660. And if you add a disk - even during
runtime! - the devfs daemon will make it so by communicating with
kernel devfs. ie the device is created with those perm's. it's not
created and then chown/chmod'd. (which could leave it vulnerable for
a split second).

Notice that the policy is maintained in userspace by devfsd.

-- 
Paul Jakma
paul@clubi.ie	http://hibernia.clubi.ie
PGP5 key: http://www.clubi.ie/jakma/publickey.txt
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