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Date: Mon, 16 Oct 1995 21:59:11 +1000
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199510161159.VAA25392@godzilla.zeta.org.au>
To: bde@zeta.org.au, mark@grondar.za
Subject: Re: Creating a /dev/random
Cc: hackers@FreeBSD.org
Sender: owner-hackers@FreeBSD.org
Precedence: bulk

>> >+			poolsize = read_random(rbuf, CLBYTES);
>> >+			c = min(iov->iov_len, CLBYTES);
>> >+			c = min(c, poolsize);
>> >+			error = uiomove(rbuf, (int)c, uio);
>> 
>> `c' should be calculated before calling rad_random() to avoid wasting
>> randomness.

>Huh? How? :-) Are you suggesting that there should be another call to
>return the number of bytes in the pool _before_ read_random is called?

	intc = imin(iov->iov_len, CLBYTES);
	poolsize = read_random(rbuf, intc);
	intc = imin(intc, poolsize);

It the caller reads 1 byte at a time, then the original version throws
away up to CLBYTES-1 bytes of randomness.

Bruce