Date: Mon, 16 Oct 1995 14:33:55 +0200 From: Mark Murray <mark@grondar.za> To: Bruce Evans <bde@zeta.org.au> Cc: hackers@FreeBSD.org Subject: Re: Creating a /dev/random Message-ID: <199510161233.OAA26278@grumble.grondar.za>
next in thread | raw e-mail | index | archive | help
> >> >+ 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. AHA! The undocumented internals of *iov... Thanks. I just learnt something useful here! M -- Mark Murray 46 Harvey Rd, Claremont, Cape Town 7700, South Africa +27 21 61-3768 GMT+0200 Finger mark@grumble.grondar.za for PGP key
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199510161233.OAA26278>