Re: [PATCH] kernel/irq/proc.c: set MAX_NAMELEN 11 instead of 10 which express the maximize size of "%d" or "%u".

[Richard Weinberger <richard@nod.at>]

Am 05.10.2013 19:06, schrieb Chen Gang:
> On 10/06/2013 12:50 AM, Chen Gang wrote:
>> On 10/06/2013 12:08 AM, Richard Weinberger wrote:
>>> On Sat, Oct 5, 2013 at 5:46 PM, Chen Gang <gang.chen@asianux.com> wrote:
>>>> On 10/05/2013 11:41 PM, Joe Perches wrote:
>>>>> On Sat, 2013-10-05 at 23:19 +0800, Chen Gang wrote:
>>>>>> Theoretically, the maximize size of "%d" or "%u" is 11 (10 + '\0'), so
>>>>>> need set MAX_NAMELEN 11 instead of 10.
>>>>>
>>>>> %d can be negative.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>> Oh, really, it is incorrect. Al Viro succeeds once.  :-(
>>>>
>>>> And I should send patch v2 for it.
>>>
>>> irq is in both register_irq_proc() and unregister_irq_proc() an unsigned int.
>>> Therefore %d makes not really sense. Both should use %u.
>>> IMHO sprintf() should also get replaced by snprintf() but that's a
>>> matter of taste.
>>>
> 
> Oh, commonly, snprintf() are used for the string which can be truncated,
> and can not be used for the string which contents must not be truncated.
> 
> In our case, the name string must be not truncated (or may not unique,
> theoretically), so we have to still use sprintf().

Of course you would have to check the return value of snprintf() to detect
a truncation and abort...

Thanks,
//richard