Subject: Re: [PATCH] core: dev: don't call BUG() on bad input

From: Nicolas de Pesloüan<[email-masked]>
Date: Mon, 14 Feb 2011 14:01:44 +0100

Le 14/02/2011 13:23, Vasiliy Kulikov a écrit :
> Hi Nicolas,

Hi Vasiliy,

> On Mon, Feb 14, 2011 at 13:16 +0100, Nicolas de Pesloüan wrote:
>>> -	BUG_ON(strlen(name)>= sizeof(dev->name));
>>> +	if (strnlen(name, sizeof(dev->name))>= sizeof(dev->name)) {
>
> Ehh...  Space after ")" is needed :)

:-D

>> "size_t strnlen(const char *s, size_t maxlen) : The strnlen()
>> function returns strlen(s), if that is less than maxlen, or maxlen
>> if there is no '\0' character among the first maxlen characters
>> pointed to by s."
>>
>> How can strnlen(name, sizeof(dev->name)) be greater than sizeof(dev->name)?
>>
>> Shouldn't it be "if (strnlen(name, sizeof(dev->name)) == sizeof(dev->name))" instead?
>
> Not a big deal, but MO it's better to guard from everything that
> is not a good input by negating the check.  strnlen()<  sizeof() is OK,
> strnlen()>= sizeof() is bad.  Is "==" more preferable for net/ coding style?

Agreed, both cannot cause any troubles. == is supposed to be better from the API point of view, but 
 >= is probably more readable.

	Nicolas.