This is the registry library. The registry is basically a bunch of
hives that can be loaded from different places.

The various registry backends provide support for loading/saving
specific types of hives:

 - ldb 
 - w95 (USER.DAT-style files)
 - nt4 (NTUSER.DAT-style files)
 - gconf (GNOME configuration)
 - rpc (Remote individual hives)

Instead of opening individual hives, one can also open a 'complete'
registry by using one of these three functions:
 
 - reg_open_local() - load local registry, see below
 - reg_open_remote() - connect to remote registry over RPC
 - reg_open_wine() (not working yet)

reg_open_local() loads a set of hives based on smb.conf settings.
Lines in smb.conf should have the following syntax:

registry:<hivename> = <backend>:<location>

So an example usage could be:

registry:HKEY_CURRENT_USER = nt4:NTUSER.DAT
registry:HKEY_LOCAL_MACHINE = ldb:tdb://registry.tdb

WERR_NOT_SUPPORTED will be returned for all hives that haven't been set.

On Windows the various registry hives are loaded from:

HKEY_CURRENT_CONFIG: %SystemRoot%\System32\Config\System
HKEY_CURRENT_USER: %Profile%\NTUser.dat
HKEY_LOCAL_MACHINE\SAM: %SystemRoot%\System32\Config\Sam
HKEY_LOCAL_MACHINE\Security: %SystemRoot%\System32\Config\Security
HKEY_LOCAL_MACHINE\Software: %SystemRoot%\System32\Config\Software
HKEY_LOCAL_MACHINE\System: %SystemRoot%\System32\Config\System
HKEY_USERS\.DEFAULT: %SystemRoot%\System32\Config\Default
HKEY_LOCAL_MACHINE\HARDWARE: is autogenerated