Managing ACL's on device nodes

[Artem Kachitchkine]

> So for this I envision that hal will maintain a state file of ACL's
> granted somewhere in /var/run/hald, say /var/run/hal/acls_granted. On
> startup of hal we process this file and removes the ACL's previously
> added (want to be careful not to remove ACL's not granted by HAL). 

ACLs aren't cumulative, are they? I.e. if HAL sets the ACL, then 
something else sets the same ACL, then HAL unsets it, the ACL is unset.

-Artem.