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Re: [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic
From: |
Michael Tokarev |
Subject: |
Re: [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic |
Date: |
Mon, 26 May 2014 10:29:44 +0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 |
26.05.2014 10:25, Markus Armbruster wrote:
> Michael Tokarev <address@hidden> writes:
>
>> The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
>> has a weird bug in variable usage around expanding opts->vreader
>> array.
>>
>> There's a helper variable, vreaderOpt, which is first needlessly
>> initialized to NULL, next, conditionally, only we have to expand
>> opts->vreader, receives array expansion from g_renew() (initially
>> realloc), and next, even if we don't actually perform expansion,
>
> I don't get the "(initially realloc)" part. The sentence makes sense to
> me just fine without it, though.
I was in context of your patch which changes realloc() to g_renew().
And I failed to mention that this my patch is on top of yuors,
too - think of this comment as such a mention ;)
>> the value of this variable is assigned to the actual array,
>> opts->vreader, which was supposed to be expanded.
>>
>> So, since we expand the array by READER_STEP increments, only
>> once in READER_STEP (=4) the code will work, in other 3/4 times
>> it will fail badly.
>>
>> Fix this by not using this temp variable when expanding the
>> array, and by dropping the useless =NULL initializer too -
>> if it wasn't in place initially, compiler warned us about
>
> "would have warned us"?
Oh yeah. I tried to remember the right English construct, but
failed. This tense always escpapes my mind for some reason :)
> Much more straightforward now. Thanks!
>
> Reviewed-by: Markus Armbruster <address@hidden>
Thank you. I'll fix the comment. And I'm now ready to push
whole -trivial.
/mjt