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Date:      Mon, 20 Sep 1999 17:47:10 -0700 (PDT)
From:      Julian Elischer <julian@whistle.com>
To:        Mark Newton <newton@internode.com.au>
Cc:        gurney_j@resnet.uoregon.edu, winter@jurai.net, chuckr@mat.net, wayne@crb-web.com, freebsd-hackers@FreeBSD.ORG
Subject:   Re: what is devfs?
Message-ID:  <Pine.BSF.3.95.990920174049.6478E-100000@current1.whistle.com>
In-Reply-To: <199909210016.JAA35050@gizmo.internode.com.au>

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On Tue, 21 Sep 1999, Mark Newton wrote:

> Julian Elischer wrote:
>  
>  > On Mon, 20 Sep 1999, John-Mark Gurney wrote:
>  > > one thing that HAS to happen is the fast that some devices CAN'T "appeare"
>  > > until the devfsd says it can, unless we force a very restrictive permision
>  > > on all devices (600 or something similar) otherwise we will have security
>  > > wholes up the wazoo... don't forget about this... a devfsd daemon is
>  > > definately the way to go...
>  > 
>  > While I sharply disagree, with your assertion, I also point out that if
>  > you make such a all-singing-all-dancing devfsd, then you might as well get
>  > rid of devfs entirely, and just have devfsd make the devices using normal
>  > mknod commands.
> 
> Hmm - rip out the whole devfs infrastructure and replace it with something
> which writes tuples of (operation, devname, major, minor) to a socket
> somewhere, where "operation" is "create", "delete", "online", "offline",
> etc.  Why worry about the complexities of a vfs to handle /dev in the
> kernel when almost all of it can be done in userland?
> 
> [ Heh.  *now* there'll be some wailing and gnashing of teeth... :-) ]

It's always been the main valid alternative to devfs.  From teh driver
point-of-view it's identical.  The make_dev() call that is presently in
the drivers simply passes that information up through the socket rather
than doing the work directly. 
The 'tupple' (not really, is it?) would be
(name, major, minor, default owner, default perms, type)

The daemon would look up the device name in a configuration database where
it would find 'exceptions and deviations' as well as default behaviours.

This actually solves a few problems that devfs has. It also lses some of
the simplicity and reliability that devfs has..

With very little work we could implement both systems since the device
interface would be identical.

> 
>    - mark
> 
> ----
> Mark Newton                               Email:  newton@internode.com.au (W)
> Network Engineer                          Email:  newton@atdot.dotat.org  (H)
> Internode Systems Pty Ltd                 Desk:   +61-8-82232999
> "Network Man" - Anagram of "Mark Newton"  Mobile: +61-416-202-223
> 



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