Re: What's cooking in git.git (Apr 2021, #04; Thu, 15)

From: Jeff King <peff@peff.net>
Date: Apr 17, 2021, 08:47 UTC
Message-ID: <YHqgjR0YDDgergpS@coredump.intra.peff.net>
In-Reply-To: <nycvar.QRO.7.76.6.2104161320250.52@tvgsbejvaqbjf.bet>

On Fri, Apr 16, 2021 at 01:21:01PM +0200, Johannes Schindelin wrote:

Show 12 quoted lines

> > Looks like this fails CI on the Windows VS build. I get:
> >
> >   ++ env GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=/dev/null git config --global --list
> >   fatal: unable to access 'nul': Invalid argument
> >
> > from t1300.181. I thought we had some magic to make /dev/null work there
> > (or maybe this _is_ the magic kicking in, since it is looking for the
> > Windows-ish nul, but it is not working for some reason).
> 
> Seems that this fixes it for me:
> [...]
> Subject: [PATCH] msvc: avoid calling `access("NUL", flags)`

Doh, I should have realized it was about access() from the message. Thank you for a quick fix!

I do wonder if we should (not now, but in the longer term) ditch these access() calls in git-config entirely (and just rely on errno we see after calling fopen). The current code is a TOCTOU race (though one that is unlikely to matter much in practice).

-Peff