Re: 2.5.28 and partitions

From: Alexander Viro (
Date: Thu Aug 01 2002 - 16:27:15 EST

On Thu, 1 Aug 2002, Marcin Dalecki wrote:

> > As for the Martin's comments... Martin, if you can't write a function
> > that checks whether array of characters has a contents fitting the
> > description above - stand up and say so. Aloud. In public.
> Actually you asked me to just shut up. Becouse I assume that you guessed
> that I'm able to write the corresponding code?
> I will anser anyway ;-)
> Sure I'm able to do this. However if I hear the words parser I
> immediately think *complete* parsers in the formal sense.
> Not a bunch of reg exp guessing. Neither do

Newsflash: for Homsky-3 grammar "reg exp guessing" _IS_ complete parser
in the formal sense.

> I think about that error prone scanning for '\0' or fumbling

OK. So "check if n bytes starting at address p contain zero and return
the distance of first zero from p if they do and n if they do not" is
error-prone task? Fiiine...

> So unless you provide me with a... well for example, *complete* BNF
> grammar definition of /proc I will always claim that using it or ASCII
> based interfaces is:

What the devil does BNF for everything somebody decided to dump in some
file in procfs have to partition tables?

> > is tough". Examples on demand, including real gems like
> > fread(&foo, sizeof(foo), 1, fp);
> > if (foo.x >= 100000 || foo.y >= 100000)
> > /* fail and exit */
> > p = (char *)malloc(foo.x * foo.y);
> > if (!p)
> > /* fail and exit */
> > for (i = 0; i < foo.x; i++)
> > fread(p + i*foo.y. 1, foo.y, fp);
> > and similar wonders (if anybody wonders what's wrong with the code above,
> > you need to learn how multiplication is defined on int and compare 10^10 with
> > 2^32). And yes, it's real-life code, from often-used programs. Used on
> > untrusted data, at that.
> Storing the constants in question in the above code sample
> as ASCII at the start of where foo is pointing at, would have hardly
> saved the poor overworked programmers mind from precisely the same
> mistake he did above. (Needless to say that you actually forgott
> to mention that the code fails on <= 32 bit systems. Inestad of
> providing te "hint" for guessing where the actual error is.)


you: "it's easy to screw up when working with ASCII strings"
me: "tossers will find a way to screw up on anything, no matter what it is;
     see example of tosser screwing up on plain arithmetics"
you: "use of ASCII wouldn't help them in that case"

Sure thing, it wouldn't. _Nothing_ short of acquiring some clue would.
Possible solutions:
        A) replace all arithmetics with BIGNUMs (and just you wait for
first out-of-memory)
        B) get rid of tossers.

Matter of taste, indeed, but I'd rather go for (B) - has a benefit of
solving many other problems.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

This archive was generated by hypermail 2b29 : Wed Aug 07 2002 - 22:00:17 EST