PHP rename() not permitted

[gencha]

I am trying to move files in PHP via rename(). The files themselves belong to the group Apache is in (www-data) and the target directory is most definitely writable by Apache as well.
Yet when I try to rename(), I get the following error:

WARNING: rename(/home/frontend/uploadclip.xml,/var/media/45ecfe0fb82968cd0244666d3b92ac4a2658d844) [<a href='function.rename'>function.rename</a>]: Operation not permitted in /var/www/admin/uploadAddToPool.php on line 55

So, to determine if access rights might be the problem here, I replace the rename() call with a system( "mv .." ); call and this works flawlessly.

I would like to avoid using system() calls but I also have no clue why rename() would fail in this scenario.

[Arndt]

I am trying to move files in PHP via rename(). The files themselves belong to the group Apache is in (www-data) and the target directory is most definitely writable by Apache as well.
Yet when I try to rename(), I get the following error:

WARNING: rename(/home/frontend/uploadclip.xml,/var/media/45ecfe0fb82968cd0244666d3b92ac4a2658d844) [<a href='function.rename'>function.rename</a>]: Operation not permitted in /var/www/admin/uploadAddToPool.php on line 55

So, to determine if access rights might be the problem here, I replace the rename() call with a system( "mv .." ); call and this works flawlessly.

I would like to avoid using system() calls but I also have no clue why rename() would fail in this scenario.

I suppose the PHP 'rename' directly calls the system call 'rename'. It cannot move files across file systems. The 'mv' program copies the file in that case.

[CyberJack]

Have you tried a copy() and a unlink()?
It may give you a better look at what goes wrong (copy or removal of the original file).

if( copy('/home/frontend/uploadclip.xml', '/var/media/45ecfe0fb82968cd0244666d3b92ac4a2658d844') )
{
unlink('/home/frontend/uploadclip.xml');
}

[gencha]

I suppose the PHP 'rename' directly calls the system call 'rename'. It cannot move files across file systems. The 'mv' program copies the file in that case.
But the documentation at http://us2.php.net/manual/en/function.rename.php states that since 4.3.3 it is able to move files across partitions.
I kinda thought that would apply here.

[gencha]

Have you tried a copy() and a unlink()?
It may give you a better look at what goes wrong (copy or removal of the original file).

if( copy('/home/frontend/uploadclip.xml', '/var/media/45ecfe0fb82968cd0244666d3b92ac4a2658d844') )
{
unlink('/home/frontend/uploadclip.xml');
}
In fact, that works perfectly. Thanks. No idea why I didn't try that...

[gencha]

I suppose the PHP 'rename' directly calls the system call 'rename'. It cannot move files across file systems. The 'mv' program copies the file in that case.
I wrote a small C application to see what rename() would give me for the same input parameters. You seem to be correct, it fails as well.
The resulting error is "Error renaming file: Invalid cross-device link". But I have yet to find out the deeper meaning of this.
Thanks though.