__FILE__ and sym-links

I have a problem I can't crack.

I have the following example directory structure
/some_arbitrary_path/htdocs/ ( also $_SERVER['DOCUMENT_ROOT'] )
/some_arbitrary_path/htdocs/common is a symbolic link to
/some_different_path/common/

if $_SERVER['DOCUMENT_ROOT'].'/common/some_script.php' gets
included...
it works just fine, however, within some_script.php
__FILE__ == /some_different_path/common/some_script.php

So:
How do I determine that __FILE__ does in fact fall inside the
DOCUMENT_ROOT tree?
and/or, get a the value of the path that I included (one with /
arbitrary_path)
and/or, determine the "html path" to some_script.php is '/common/
some_script.php'?

Re: __FILE__ and sym-links

On Wed, 21 Nov 2007 23:56:50 +0100, BKDotCom =

wrote:

> I have a problem I can't crack.
>
> I have the following example directory structure
> /some_arbitrary_path/htdocs/ ( also $_SERVER['DOCUMENT_ROOT'] )
> /some_arbitrary_path/htdocs/common is a symbolic link to
> /some_different_path/common/
>
> if $_SERVER['DOCUMENT_ROOT'].'/common/some_script.php' gets
> included...
> it works just fine, however, within some_script.php
> __FILE__ == /some_different_path/common/some_script.php
>
> So:
> How do I determine that __FILE__ does in fact fall inside the
> DOCUMENT_ROOT tree?
> and/or, get a the value of the path that I included (one with /
> arbitrary_path)
> and/or, determine the "html path" to some_script.php is '/common/
> some_script.php'?

How the user 'got' there is usually easily checked by examing the $_SERV=
ER =

array (PHP_SELF/REQUEST_URI), this only tells you about the 'entrypoint'=
=

though, not the location of the file ro the root if it was included.

To the real question:"Can I determine how this file was included?": Not =
=

easily AFAIK. You could play around with __FILE__, get_included_files(),=
=

is_link() && readlink(). What are you going to use this information for =
=

BTW? You might be better off checking getcwd() then __FILE__...


A quick mock up:
function _euhm_included_by_name_or_something($file){
$included =3D get_included_files();
//straight include
if(array_search($file,$included)!==false) return $file;
foreach($included as $include){
//included as symlink?
if(is_link($include) && readlink($include)==$file) return $include=
;
}
return false;
}
//usage:
_euhm_included_by_name_or_something(__FILE__);

With a file included multiple times using different symlinks, one cannot=
=

determine by which one it was AFAIK. And offcourse, one might have to wa=
lk =

through the path do determine wether one of the directories was a symlin=
k, =

absolute paths differ from relative ones, etc, etc (haven't got a linux =
=

box to test properly handy right now) but you get the idea.

A really, really dirty way of determining how this file was called, is =

offcourse to perform a debug_backtrace() as the first statement in the =

file, and check with what arguments a possible include_*/require_* was =

actually called. Unless absolutely needed, I'd stay clear of this option=
: =

debug_backtrace() should be for debugging, and can create a considerable=
=

unwanted overhead.
-- =

Rik Wasmus

Re: __FILE__ and sym-links

Thanks for your help..
I figured out how to accomplish this.. in a nutshell:

I explode('/',__FILE__);
I then loop backwards through the array prepending a "relative path"
with the current explosion value.. until
realpath($_SERVER['DOCUMENT_ROOT'].'/'.$rel_path) == __FILE__