Re: [PATCH] abspath.c: use PATH_MAX in real_path_internal()

From: Karsten Blees <karsten.blees@gmail.com>
Date: Jul 17, 2014, 23:02 UTC
Message-ID: <53C8561F.5090600@gmail.com>
In-Reply-To: <xmqqoawnq2vv.fsf@gitster.dls.corp.google.com>

Am 17.07.2014 20:03, schrieb Junio C Hamano:

Show 18 quoted lines

> Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:
> 
>> This array 'cwd' is used to store the result from getcwd() and chdir()
>> back. PATH_MAX is the right constant for the job. On systems with
>> longer PATH_MAX (eg. 4096 on Linux), hard coding 1024 fails stuff,
>> e.g. "git init". Make it static too to reduce stack usage.
>>
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
> 
> Thanks.  It seems that this 1024 has been with us since the
> beginning of this piece of code.  I briefly wondered if there are
> strange platform that will have PATH_MAX shorter than 1024 that will
> be hurt by this change, but the result in cwd[] is used to grow the
> final result bufs[] that is sized based on PATH_MAX anyway, so it
> will not be an issue (besides, the absurdly short one seems to be
> a different macro, MAX_PATH, on Windows).
>

Indeed, there's a strange platform where PATH_MAX is only 259. With Unicode support, the current directory can be that many wide characters, which means up to 3 * PATH_MAX UTF-8 bytes (if all of them are CJK).

I don't think this will be a problem, though, as the return buffer is PATH_MAX-bounded as well.