Re: [PATCH 1/3] ewah_read_mmap: bounds-check mmap reads

From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: "SZEDER Gábor" <szeder.dev@gmail.com>,
	"Luat Nguyen" <root@l4w.io>,
	"Git mailing list" <git@vger.kernel.org>
Subject: Re: [PATCH 1/3] ewah_read_mmap: bounds-check mmap reads
Date: Fri, 15 Jun 2018 12:42:10 -0700	[thread overview]
Message-ID: <xmqqwouzzvjh.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20180615172121.GA3067@sigill.intra.peff.net> (Jeff King's message of "Fri, 15 Jun 2018 13:21:22 -0400")

Jeff King <peff@peff.net> writes:

> On Fri, Jun 15, 2018 at 07:10:28PM +0200, SZEDER Gábor wrote:
>
>> > I said "yuck" because the original does not work if there happen to
>> > be more than (or for that matter, less than) one '.bitmap' file
>> > there.  But at least as long as there is one, it should work ;-)
>> 
>> Well, the test starts with 'git repack -ad', so there can be only one
>> bitmap file.  (Unless something is broken, of course, but the second
>> test would catch that much earlier.)
>
> Right. I almost put "head -1" in there, but we know that we just created
> a single bitmap. And my thought was that if we don't, the test would
> blow up horribly, which is exactly what you want.

Yes, and "file=$(ls gl*b) &&" breaks if there is no matching file
(iow, I said 'for that matter, less than' which was incorrect), so
the original is OK in practice.

Thanks.