Re: PATH_MAX (Re: [PATCH] system_path: use a static buffer)

[Lasse Makholm <lasse.makholm@gmail.com>]

On 21 March 2011 10:47, Carlos Martín Nieto <cmn@elego.de> wrote:
> On vie, 2011-03-18 at 06:38 -0500, Jonathan Nieder wrote:
>> Hi,
>>
>> Nguyen Thai Ngoc Duy wrote:
>>
>> > It was pointed out elsewhere [1] that PATH_MAX only specifies max
>> > length of a path element, not full path. I think we'd need to stay
>> > away from preallocated PATH_MAX-sized arrays.
>>
>> No, PATH_MAX is actually the maximum length of a path, and when you
>> use, say, open(2), it will fail if your path is longer than that.  The
>> maximum length of a path component on most filesytems is 255 or 256;
>> PATH_MAX on Linux is 4096.
>>
>> It is indeed possible to have paths with length longer than that.  The
>> way to support that is to use relative paths wherever possible, which
>
>  So what PATH_MAX describes is the maximum length of a string
> representing a path, but not necessarily the length of the path itself.

According to this at least, PATH_MAX is bogus:
http://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html

I think the sane thing would be to never rely on a fixed max path length.

--
/Lasse