[ros-dev] Writing an API-Test for localspl.dll

[Colin Finck]

Hi all,

In order to verify the exact behaviour of localspl.dll on Windows Server
2003, I'm trying to write an API-Test for it. This is no problem for
winspool.drv or even the Print Processor functions of localspl.dll, but
its Print Provider functions pose some serious problems:

* You get a table of function pointers by calling InitializePrintProvidor.

* Instead of just handing over the pointers, this function first calls
many undocumented ones from spoolss.dll, including CacheAddName,
CacheCreateAndAddNode, GetServerPolicy, SplInitializeWinSpoolDrv,
SplIsUpgrade.

* Out of these undocumented functions, GetServerPolicy is the most
problematic one, because it itself relies on a function pointer given by
spoolsv.exe to spoolss.dll in an initialization function. My API-Test is
not spoolsv.exe, so I don't initialize spoolss.dll the same way. Thus,
GetServerPolicy will fail and InitializePrintProvidor as well.

* For now, I worked around this problem by stubbing these functions in
my spoolss.dll. I.e., GetServerPolicy just returns TRUE there and I get
further.

* On top of this, InitializePrintProvidor also makes use of
RevertToPrinterSelf and ImpersonatePrinterClient. To let these functions
succeed, the current thread actually needs to impersonate a user. For
now, I worked around this problem by doing:

	OpenProcessToken(GetCurrentProcess(), TOKEN_DUPLICATE, &hToken);
	DuplicateToken(hToken, SecurityImpersonation, &hDup);
	ImpersonateLoggedOnUser(hDup);

before calling InitializePrintProvidor.

* Finally, this lets InitializePrintProvidor succeed and it gave me the
table of function pointers.
Unfortunately, even simple query functions like fpEnumPrinters do a
RevertToPrinterSelf and then expect to be in the SYSTEM context of
spoolsv.exe. When my API-Test was just run in a usual Administrator user
context under Windows Server 2003, fpEnumPrinters didn't succeed.
For now, I worked around this problem by running my test program as a
service in the SYSTEM context.


With all these problems presented, can you think of any way how I can
now write a reliable API-Test for localspl.dll that could be run
regularly under Windows Server 2003 and ReactOS?

One idea would be to load the system spoolss.dll and then rewire the
GetServerPolicy import to a function that just returns TRUE all the time.
Still then, I have the problem that my API-Test would need to be run in
the SYSTEM security context.

Creative ideas are welcome! :)


Cheers,

Colin