linux-kernel - Re: gcc fixed size char array initialization bug

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Date:	Fri, 3 Aug 2007 11:40:01 +0800
From:	WANG Cong <xiyou.wangcong@...il.com>
To:	Satyam Sharma <satyam@...radead.org>
Cc:	Jan Engelhardt <jengelh@...putergmbh.de>,
	Guennadi Liakhovetski <g.liakhovetski@....de>,
	linux-kernel@...r.kernel.org
Subject: Re: gcc fixed size char array initialization bug - known?

On Fri, Aug 03, 2007 at 08:47:56AM +0530, Satyam Sharma wrote:
>
>
>On Thu, 2 Aug 2007, Jan Engelhardt wrote:
>
>> On Aug 2 2007 21:55, Guennadi Liakhovetski wrote:
>> > [...]
>> >
>> >	struct {
>> >		char c[4];
>> >		int i;
>> >	} t;
>> >	t.i = 0x12345678;
>> >	strcpy(t.c, c);
>> >
>> >and t.i is silently corrupted. Just wanted to ask if this is known, 
>> >really...
>> 
>> What does this have to do with the kernel? The string "0123" is
>> generally _five_ characters long, so c[4] is not enough.
>> Or use strncpy.
>
><nitpicking>
>
>While we're talking of null-termination of strings, then I bet you
>generally want to be using strlcpy(), really. Often strncpy() isn't
>what you want. Of course, if that buffer isn't a string at all, then
>you should be using memfoo() functions and not strbar() ones in the
>first place ...

Afaik, strlcpy() and strlcat() are NOT standard C library functions.
But, I know, they are available in Linux kernel. ;) And yes, they
are better than strn{cpy,cat}().

Regards.

-- 
_   /|
\'o.O'
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   U 
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