From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 22 Aug 2012 18:26:36 GMT
Subject: Re: Porting git to HP NonStop
Message-ID: <7vy5l67pgj.fsf@alter.siamese.dyndns.org>
In-Reply-To: <CA+sFfMedWVAgqvHS67V6L=ROjdN6M3p3pYTUDk98xgozX4djEw@mail.gmail.com>

Brandon Casey <drafnel@gmail.com> writes:

> On Wed, Aug 22, 2012 at 10:41 AM, Johannes Sixt <j6t@kdbg.org> wrote:
>> Am 22.08.2012 19:00, schrieb Brandon Casey:
>>>  So I think the body of [compat_mkdir] can become
>>> something like:
>>>
>>>    if (len && dir[len-1] == '/')
>>>        dir = tmp_dir = xstrndup(dir, len-1);
>>
>> Don't use x* wrappers in the compat layer, at least not those that
>> allocate memory: They behave unpredictably due to try_to_free_routine
>> and may lead to recursive invocations.
>
> I thought that rule only applied to die handlers.  i.e. don't use the
> x* wrappers to allocate memory in a die handler like
> compat/win32/syslog.c.  At least that's what I wrote in 040a6551 when
> you pointed out this issue back then.
>
> Admittedly, it could get pretty sticky trying to trace the die
> handlers to ensure they don't invoke your new compat/ function.  So,
> yeah, adopting this rule of not using x* wrappers that allocate memory
> in compat/ generally seems like a good idea.
>
> Should we also try to detect recursive invocation of die and friends?

> In theory recursion could be triggered by any die handler that makes
> use of a code path that calls an x* wrapper that allocates memory,
> couldn't it?

Correct, but at that point we will end up dying anyway, so...