/*++

Copyright (C) Microsoft Corporation, All Rights Reserved.

Module Name:

dllsup.cpp

Abstract:

This module contains the implementation of the UMDF VirtualSerial Sample

Driver's entry point and its exported functions for providing COM support.

This module can be copied without modification to a new UMDF driver. It

depends on some of the code in comsup.cpp & comsup.h to handle DLL

registration and creating the first class factory.

This module is dependent on the following defines:

MYDRIVER_TRACING_ID - A wide string passed to WPP when initializing

tracing. For example, VirtualSerial uses

L"Microsoft\\UMDF\\VirtualSerial"

MYDRIVER_CLASS_ID - A GUID encoded in struct format used to

initialize the driver's ClassID.

These are defined in internal.h for the sample. If you choose

to use a different primary include file, you should ensure they are

defined there as well.

Environment:

WDF User-Mode Driver Framework (WDF:UMDF)

--*/

#include "internal.h"

#include "dllsup.tmh"

const GUID CLSID_MyDriverCoClass = MYDRIVER_CLASS_ID;

BOOL

WINAPI

DllMain(

HINSTANCE ModuleHandle,

DWORD Reason,

PVOID /* Reserved */

)

/*++

Routine Description:

This is the entry point and exit point for the I/O trace driver. This

does very little as the I/O trace driver has minimal global data.

This method initializes tracing.

Arguments:

ModuleHandle - the DLL handle for this module.

Reason - the reason this entry point was called.

Reserved - unused

Return Value:

TRUE

--*/

{

UNREFERENCED_PARAMETER( ModuleHandle );

if (DLL_PROCESS_ATTACH == Reason)

{

//

// Initialize tracing.

//

WPP_INIT_TRACING(MYDRIVER_TRACING_ID);

}

else if (DLL_PROCESS_DETACH == Reason)

{

//

// Cleanup tracing.

//

WPP_CLEANUP();

}

return TRUE;

}

HRESULT

STDAPICALLTYPE

DllGetClassObject(

_In_ REFCLSID ClassId,

_In_ REFIID InterfaceId,

_Outptr_ LPVOID *Interface

)

/*++

Routine Description:

This routine is called by COM in order to instantiate the

driver callback object and do an initial query interface on it.

This method only creates an instance of the driver's class factory, as this

is the minimum required to support UMDF.

Arguments:

ClassId - the CLSID of the object being "gotten"

InterfaceId - the interface the caller wants from that object.

Interface - a location to store the referenced interface pointer

Return Value:

S_OK if the function succeeds or error indicating the cause of the

failure.

--*/

{

PCClassFactory factory;

HRESULT hr = S_OK;

*Interface = NULL;

//

// If the CLSID doesn't match that of our "coclass" (defined in the IDL

// file) then we can't create the object the caller wants. This may

// indicate that the COM registration is incorrect, and another CLSID

// is referencing this drvier.

//

if (IsEqualCLSID(ClassId, CLSID_MyDriverCoClass) == false)

{

Trace(

TRACE_LEVEL_ERROR,

L"ERROR: Called to create instance of unrecognized class (%!GUID!)",

&ClassId

);

return CLASS_E_CLASSNOTAVAILABLE;

}

//

// Create an instance of the class factory for the caller.

//

factory = new CClassFactory();

if (NULL == factory)

{

hr = E_OUTOFMEMORY;

}

//

// Query the object we created for the interface the caller wants. After

// that we release the object. This will drive the reference count to

// 1 (if the QI succeeded an referenced the object) or 0 (if the QI failed).

// In the later case the object is automatically deleted.

//

if (SUCCEEDED(hr))

{

hr = factory->QueryInterface(InterfaceId, Interface);

factory->Release();

}

return hr;

}