Re: [BUG/PATCH] setup: Copy an environment variable to avoid overwrites

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 5, 2013, 04:38 UTC
Message-ID: <7vk3rsqm6u.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CACsJy8BeuV8esGTWsQiT_G9pZE28s5KJxH6+dzdhioLgmSiNVg@mail.gmail.com>

Duy Nguyen <pclouds@gmail.com> writes:

> Maybe we could all this into a wrapper? If getenv() here has a
> problem, many other places may have the same problem too. This
> simplifies the change. But one has to check that getenv() must not be
> used in threaded code.

That needs to be done regardless, if we care; POSIX explicitly says getenv() need not be thread-safe.

I personally do not think a wrapper with limited slots is a healthy direction to go. Most places we use getenv() do not let the return value live across their scope, and those that do should explicitly copy the value away. It's between validating that there is _no_ *env() calls in the codepath between a getenv() call and the use of its return value, and validating that there is at most 4 such calls there. The former is much easier to verify and maintain, I think.