Re: /proc/bus/pci odd behavior

Martin Mares (mj@ucw.cz)
Sat, 17 Oct 1998 23:40:18 +0200


Hello,

> Martin, you _shall_ change either your documentation or your code or both
> in a way that will prevent this feature from being a _trap_ that let users
> break their systems.

Changing of /proc/bus/pci documentation is trivial since there exists
no such documentation :-) Users who don't want to use PCI config registers
in their own code are expected to use the pciutils and lspci man pages warn
about this problem since ages.

> BTW, I am still expecting from you the text of the PCI specifications, you
> seemed to refer to, about device specific configuration space being
> required to allow reads without side effect. It will not be a problem if
> you didn't find this text, since I didn't find it too.

I tried to look it up, but I failed. It was either my own fantasy motivated
by "the spirit of PCI" :) or there is some obscure notice at some obscure place
I didn't look at now (aka unable to grep on dead trees :)).

> Anyway, real software must take into account real hardware.

We _do_ take into account real hardware. We already disallow access to
anything else than the standard header to ordinary users. Root is expected
to know what he is doing and system interfaces should not be obscurified
just to make the machine uncrashable by root who types commands he doesn't
understand. /proc/ioports is just the same story and nobody is worried
about it -- do you see any difference?

Have a nice fortnight

-- 
Martin `MJ' Mares   <mj@ucw.cz>   http://atrey.karlin.mff.cuni.cz/~mj/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
"For every complex problem, there's a solution that is simple, neat and wrong."

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