From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alexander Holler <holler@ahsoftware.de>
Date: Tue, 24 May 2011 00:12:06 +0200
Subject: [U-Boot] [PATCH V2] memcpy/memmove: Do not copy to same address
In-Reply-To: <20110523215533.7B6FCCF5CA6@gemini.denx.de>
References: <1302591520-12517-1-git-send-email-weisserm@arcor.de>
	<1306141435-24001-1-git-send-email-weisserm@arcor.de>
	<4DDACC8B.6090507@ahsoftware.de>
	<20110523215533.7B6FCCF5CA6@gemini.denx.de>
Message-ID: <4DDADBB6.30607@ahsoftware.de>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

Am 23.05.2011 23:55, schrieb Wolfgang Denk:
> Dear Alexander Holler,
>
> In message<4DDACC8B.6090507@ahsoftware.de>  you wrote:
>>
>>> --- a/lib/string.c
>>> +++ b/lib/string.c
>>> @@ -467,6 +467,9 @@ void * memcpy(void *dest, const void *src, size_t count)
>>>    	unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
>>>    	char *d8, *s8;
>>>
>>> +	if (src == dest)
>>> +		return dest;
>>> +
>>
>> here is the same, as in the patch I've commented before. There exist no
>> reason to add a check for identity to memcpy() because memcpy doesn't
>> support overlapping regions (and identity is just a special case of
>> overlapping regions). If something might call memcpy() with overlapping
>> or identical regions, it should use memmove().
>
> In an ideal world, nobody will ever use any interfces in a
> non-compliant or incorrect way.
>
> In reality, all kind of errors happen.  A little defensive programming
> like the one above helps a lot, so please stop complaining even if you
> think you don't need this.

So you I will look forward to checks for NULL pointers and similiar in 
all C standard functions implemented in u-boot to circumvent tons of 
possible real world bugs in all callers of strcpy, strlen, mem* and 
whatever.

Reads promising,

regards,

Alexander