linux-kernel - Re: [PATCH 1/4] drivers/net/enic: decrement sizeof size in strncmp

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Message-ID:  <4AFBE0B4.6070904@web.de>
Date:	Thu, 12 Nov 2009 11:17:24 +0100
From:	Jörg-Volker Peetz <jvpeetz@....de>
To:	linux-kernel@...r.kernel.org
Cc:	netdev@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject:  Re: [PATCH 1/4] drivers/net/enic: decrement sizeof size in strncmp

Julia Lawall wrote:
> From: Julia Law all <julia@...u.dk>
> 
> As observed by Joe Perches, sizeof of a constant string includes the
> trailing 0.  If what is wanted is to check the initial characters of
> another string, this trailing 0 should not be taken into account.  If an
> exact match is wanted, strcmp should be used instead.
> 
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@
> expression foo;
> constant char *abc;
> @@
> 
> strncmp(foo, abc, 
> - sizeof(abc)
> + sizeof(abc)-1
>  )
> // </smpl>
> 
<snip>
How about this pattern (uses length of first argument):

strncmp(foo, abc,
- sizeof(foo)

?
-- 
Best regards,
Jörg-Volker.

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