[PATCH] locale: Avoid zero-length array in _nl_category_names [BZ #24962]

[Martin Sebor]

On 9/5/19 8:29 AM, Florian Weimer wrote:
> * Martin Sebor:
> 
>> On 9/5/19 7:25 AM, Jeff Law wrote:
>>> On 9/5/19 1:34 AM, Florian Weimer wrote:
>>>> (Martin, can you give this a test using GCC 10?  I don't expect any
>>>> issues because the zero-length array is completely gone.  The patch
>>>> passed testing on x86_64-linux-gnu without regressions, but with GCC 9.)
>>>>
>>>> The union wrapper is unnecessary because C allows to read any object
>>>> as a sequence of chars.
>>>>
>>>> 2019-09-05  Florian Weimer  <fweimer@redhat.com>
>>>>
>>>> 	[BZ #24962]
>>>> 	* locale/localeinfo.h (_nl_category_names): Remove union wrapper.
>>>> 	(_nl_category_names_get): New function.
>>>> 	* intl/dcigettext.c (category_to_name): Call it.
>>>> 	* locale/findlocale.c (_nl_find_locale): Likewise.
>>>> 	* intl/loadlocale.c (_nl_load_locale): Likewise.
>>>> 	* locale/newlocale.c (__newlocale): Likewise.
>>>> 	* locale/setlocale.c (_nl_category_names): Adjust definition.
>>>> 	(_nl_category_name_idxs): Likewise.
>>>> 	(new_composite_name): Call _nl_category_names_get.
>>>> 	(setlocale): Likewise.
>>> Might be easier for me than Martin.  I just threw it into my github
>>> repo, so my tester will pick it up as of now.  Will report back in a few
>>> hours.
>>
>> Thanks Jeff.  I'm sure your coverage will be more comprehensive
>> than mine.  (The warning Florian is fixing only shows up with
>> the patch for PR 91631 I posted yesterday so you need both in
>> your tested to verify them.)
>>
>> It's pretty easy for me to test it on x86_64-linux: with your
>> patch, Florian, and my enhanced GCC 10 I don't see any warnings.
> 
> Thanks.  Do you (or anyone else) have any comments on the patch itself?
> I need some sort of review before I can push it. 8-)

It's close to what I suggested in the bug so LGTM :)

As an aside, an anonymous struct in a union was among the issues
I mentioned in the other thread (see N2038), so it's good to get
rid of even if this code is only compiled with GCC (and maybe
also Clang?)

Martin