[PATCH][BZ #16453] Don't use alloca in addgetnetgrentX

[Carlos O'Donell]

On 01/15/2014 10:32 AM, Siddhesh Poyarekar wrote:
> On 15 January 2014 20:57, Mike Frysinger <vapier@gentoo.org> wrote:
>> On Wednesday 15 January 2014 06:34:52 Siddhesh Poyarekar wrote:
>>> The bug report has a reproducer and I verified that the reproducer is
>>> fixed with this patch.  OK to commit?
>>
>> is there no way for us to set up local paths for networking files specifically
>> for testing purposes ?  seems like a pretty big hole in our testing abilities.
>>
> 
> The paths are hardcoded, which is why this is difficult and because of
> that, nscd testing is essentially a noop.  The chroot-based testing
> framework that Ryan is working on will help this quite a bit.
> 
>>> +                                 buflen = MAX (2 * buflen,
>>> +                                               buflen + 2 * needed);
>>> +                                 char *newbuf = xrealloc (buffer, buflen);
>>> +                                 buffer = newbuf;
>>
>> why newbuf ?  this should work fine:
>>         buffer = xrealloc (buffer, buflen);
>>
>>> -                       extend_alloca (buffer, buflen, newsize);
>>> +                     buflen *= 2;
>>> +                     char *newbuf = xrealloc (buffer, buflen);
>>> +                     buffer = newbuf;
>>
>> same here
> 
> Thanks, I'll fix these when I commit, provided there are no other
> issues with the patch.

It looks good to me too. Removing alloca as much as possible is
a security win, and I agree with your analysis that this isn't
a performance issue (until someone shows it is).

Testing nscd is something we need to work on, and cross-testing
makes that more difficult.

Cheers,
Carlos.