Helper Tool on FireWire

FROM : Gerriet M. Denkmann
DATE : Sat Jun 24 22:33:29 2006

I have an app which uses a small helper tool which runs setuid root.
Everything works perfectly.

But if the computer boots from some partition A and the helper tool 
resides on some partition B (A­B) and if B is accessed via FireWire 
it just doesn't work.

Normally I get something like this:
2006-06-24 11:22:16.875 Test Helper[857] path:    /tmp/Test Helper
2006-06-24 11:22:16.879 Test Helper[857] owner:  root (0)
2006-06-24 11:22:16.880 Test Helper[857] rights:  4555
2006-06-24 11:22:16.880 Test Helper[857] geteuid: 0    Ok

But when "Test Helper" is on some FireWire partition I get:
2006-06-24 11:20:37.040 Test Helper[851] path:    /Volumes/FireWire 
Disk/tmp/Test Helper
2006-06-24 11:20:37.043 Test Helper[851] owner:  root (0)
2006-06-24 11:20:37.043 Test Helper[851] rights:  4555
2006-06-24 11:20:37.044 Test Helper[851] geteuid: 502  Error

This might be a bug or a security feature or I might be doing 
something very stupid.

But: is there a way to make this FireWire partition behave like an 
internal disk? (Finder -> Info has a switch "Ignore ownership on this 
volume" which is NOT checked).
And: how can I know whether a directory resides on a FireWire partition?
And: is there some folder which is guaranteed to reside on the boot 
partition? Like /private/tmp - but this might be a symbolic link 
pointing to some other partition.

All this on 10.4.6

Kind regards

Gerriet.