Re: [PATCH 4/11] use ether_addr_equal_64bits

Ben Greear
2013-12-31T15:55:00Z

On 12/30/2013 10:32 PM, Julia Lawall wrote:
>>>>> I'm just thinking of a programmer, e.g. changing a struct like this:
>>>>>
>>>>> struct foo {
>>>>> u8 addr[ETH_ALEN];
>>>>> - u16 dummy;
>>>>> };
>>
>> I don't know of a way to catch that.
>> Anyone else?
>
> Well, one could have a semantic patch that checks for that. But the
> problem is that it is very slow, and it only covers the cases that I can
> transform automatically, which currently means no pointers, only explicit
> arrays.
>
> On the other hand, I am finding the structure definition, so I can easily
> update the structure definition with an appropriate comment.
>
> struct foo {
> u8 addr[ETH_ALEN]; /* must be followed by two bytes in the structure */
> u16 dummy;
> };
>
> Unfortunately it is kind of verbose. Could there be an attribute? That
> could even easily be checked.

Can you not just add a build-time macro to check that sizeof(foo) >= 8
for each of these struct foos? Or, is it required that the dummy field
be there and be not used by anything else?

Thanks,
Ben

>
> julia
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--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com