linux-kernel - RE: get amount of "entropy" in /dev/random ?

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Message-ID: <MDEHLPKNGKAHNMBLJOLKIEEHHDAC.davids@webmaster.com>
Date:	Tue, 2 Oct 2007 08:49:36 -0700
From:	"David Schwartz" <davids@...master.com>
To:	"Kernel Linux" <linux-kernel@...r.kernel.org>
Subject: RE: get amount of "entropy" in /dev/random ?

> From the userlevel, can I get an estimate of  "amount of entropy"
> in /dev/random, that is, the estimate of number of bytes
> readable until it blocks ? Of course multiple processes
> can read bytes and this would not be exact ... but still .. as an upper
> boundary estimate ?
>
> Thanks
> Yakov

Yes. Look in drivers/char/random.c at the random_ioctl handler. You will see
RNDGETENTCNT.

DS

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