Re: [PATCH 01/11] mingw: avoid accessing uninitialized memory in `is_executable()`

From: Junio C Hamano <gitster@pobox.com>
Date: Jun 16, 2022, 20:20 UTC
Message-ID: <xmqqilp0s6lk.fsf@gitster.g>
In-Reply-To: <xmqqmtecs6ws.fsf@gitster.g>

Junio C Hamano <gitster@pobox.com> writes:

Show 5 quoted lines

>> Hmm, but buf _is_ initialized fully?  Line 149:
>>
>>         char buf[3] = { 0 };
>
> Ahh, yeah, that changes the landscape quite a bit.

Just for reference, this piece of code has been correct ever since it was introduced to help.c by cc3b7a97 (Windows: Make 'git help -a' work., 2008-01-14). With a larger context, we can see buf[3] that is NUL filled, which receives 2 bytes by read(), and strcmp() does look semantically more correct than memcmp(), even though there probably shouldn't be any correctness or performance difference.

So, strcmp -> memcmp in this case is a strict dis-improvement. I merged it already to 'next', but I haven't pushed the result out, so I'll redo 'next' before I push the result out.

Thanks.