[185] in The Cryptographic File System users list
using /dev/urandom (was are there many active users...)
daemon@ATHENA.MIT.EDU (Brian Edmonds)
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To: cfs-users@research.att.com
Subject: using /dev/urandom (was are there many active users...)
References: <m3wvklxpxu.fsf@yuri.gweep.bc.ca>
<20000524093619.A40679@caerdonn.eurocontrol.fr>
From: Brian Edmonds <brian@gweep.bc.ca>
Date: 24 May 2000 08:18:36 -0700
In-Reply-To: Ollivier Robert's message of "Wed, 24 May 2000 09:36:19 +0200"
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Ollivier Robert <roberto@eurocontrol.fr> writes:
> And Linux specific (like far too many free software projects these
> days).
It's unfortunate, but when you're making a new filesystem, if you want
to get the best performance that usually means kernel development, and
that usually means OS specific. CFS is cool in that it's very portable,
and I've always wondered why there weren't more cool NFS hacks, but it
does burn cycles to achieve it. Which given processor speeds these days
may be a reasonable design decision, but that's a different discussion.
> Have you looked at why it loops ? Could you post here your patch for
> using /dev/urandom ? The various *BSD have it too so I'm interested.
I attached to a looping process with gdb, and it was stuck waiting for
an itimer alarm that apparently never came. I didn't feel up to
debugging code that was rather obscure to me (I'm not a cryptographer
and make no claims of understanding randomness), so I just removed the
bulk of the code in the module and replaced the low level randomness
function with a simple one that reads from /dev/urandom[1].
Thus I don't really have a patch, sorry; it was a quick hack to make
things work for me. If there is serious interest in this I could go
back and redo it in a more standard manner so I could produce a real
patch, but if Matt's planning a 2.0 release RSN, as I've been told by
many people since my post, it may not be worth the trouble.
Brian.
[1] I realize this may not generate as good a randomness as /dev/random,
but it was an easy hack, and almost certainly good enough for my basic
needs.
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