linux-kernel - Re: [PATCH 2/2] lib: vsprintf.c remove macros defining strict string functions

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Date:	Wed, 07 May 2008 12:20:46 -0700
From:	Harvey Harrison <harvey.harrison@...il.com>
To:	Alexey Dobriyan <adobriyan@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] lib: vsprintf.c remove macros defining strict
	string functions

On Thu, 2008-05-08 at 00:09 +0400, Alexey Dobriyan wrote:
> On Wed, May 07, 2008 at 11:25:29AM -0700, Harvey Harrison wrote:
> > Directly code the strict string conversion functions rather than using
> > defining macros.  Pull out a small helper to check the strict conditions
> > required at the end of a string (nul-terminated or newline).
> 
> > Add additional checks in strict_strtol and strict_strtoll for numeric
> > overflow of the signed types.
> 
> C interer ranges are asymmetric.

Yes, and LLONG_MAX = -LLONG_MIN + 1...so it will reject string values
of LLONG_MIN...easily fixed if we want it I guess.

> 
> These "strict_" functions are a farce. No amount of afterchecking will
> save you if there is trivial wraparound in core function.
> 

That's also true, I guess it depends on how far we want to go.  And
after that point, just stick a WARN_ON and return -EINVAL.

I'm not sure where the balance is, but I think my patch is still on
the useful side of it.

> 	Alexey "kstrtonum" Dobriyan
> 
> > + */
> > +static int strict_checktail(size_t len, const char *cp, const char *tail)
> 
> Name simply sucks.

Sure does, care to suggest something better, at least it had a
comment ;-)

Anyways, thanks for taking a look.

Harvey

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