189 lines
5.4 KiB
C
189 lines
5.4 KiB
C
/***************************************************************************
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Copyright (c) 2000 Microsoft Corporation
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Module Name:
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Dot4Usb.sys - Lower Filter Driver for Dot4.sys for USB connected
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IEEE 1284.4 devices.
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File Name:
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Util.c
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Abstract:
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Misc. Utility functions
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Environment:
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Kernel mode only
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Notes:
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THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
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KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
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PURPOSE.
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Copyright (c) 2000 Microsoft Corporation. All Rights Reserved.
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Revision History:
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01/18/2000 : created
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ToDo in this file:
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- code review and doc
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- code review w/Joby
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Author(s):
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Joby Lafky (JobyL)
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Doug Fritz (DFritz)
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****************************************************************************/
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#include "pch.h"
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/************************************************************************/
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/* DispatchPassThrough */
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/************************************************************************/
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//
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// Routine Description:
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//
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// Default dispatch routine for IRP_MJ_xxx that we don't explicitly
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// handle. Pass the request down to the device object below us.
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//
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// Arguments:
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//
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// DevObj - pointer to Device Object that is the target of the request
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// Irp - pointer to request
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//
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// Return Value:
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//
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// NTSTATUS
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//
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// Log:
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// 2000-05-03 Code Reviewed - TomGreen, JobyL, DFritz
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//
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/************************************************************************/
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NTSTATUS
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DispatchPassThrough(
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IN PDEVICE_OBJECT DevObj,
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IN PIRP Irp
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)
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{
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PDEVICE_EXTENSION devExt = DevObj->DeviceExtension;
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NTSTATUS status = IoAcquireRemoveLock( &devExt->RemoveLock, Irp );
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if( NT_SUCCESS(status) ) {
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// RemoveLock acquired, continue with request
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IoSkipCurrentIrpStackLocation( Irp );
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status = IoCallDriver( devExt->LowerDevObj, Irp );
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IoReleaseRemoveLock( &devExt->RemoveLock, Irp );
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} else {
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// unable to acquire RemoveLock - FAIL request
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Irp->IoStatus.Status = status;
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IoCompleteRequest( Irp, IO_NO_INCREMENT );
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}
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return status;
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}
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/************************************************************************/
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/* CallLowerDriverSync */
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/************************************************************************/
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//
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// Routine Description:
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//
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// Call the driver below us synchronously. When this routine returns
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// the calling routine once again owns the IRP.
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//
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// This routine acquires and holds a RemoveLock against the IRP
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// while the IRP is in the possession of drivers below us.
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//
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// Arguments:
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//
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// DevObj - pointer to Device Object that is issuing the request
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// Irp - pointer to request
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//
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// Return Value:
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//
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// NTSTATUS
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//
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/************************************************************************/
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NTSTATUS
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CallLowerDriverSync(
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IN PDEVICE_OBJECT DevObj,
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IN PIRP Irp
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)
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{
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PDEVICE_EXTENSION devExt = DevObj->DeviceExtension;
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NTSTATUS status = IoAcquireRemoveLock( &devExt->RemoveLock, Irp );
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if( NT_SUCCESS(status) ) {
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KEVENT event;
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KeInitializeEvent( &event, NotificationEvent, FALSE );
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IoSetCompletionRoutine( Irp, CallLowerDriverSyncCompletion, &event, TRUE, TRUE, TRUE );
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status = IoCallDriver( devExt->LowerDevObj, Irp );
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if( STATUS_PENDING == status ) {
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KeWaitForSingleObject( &event, Executive, KernelMode, FALSE, NULL );
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status = Irp->IoStatus.Status;
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}
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IoReleaseRemoveLock( &devExt->RemoveLock, Irp );
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} else {
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TR_FAIL(("util::CallLowerDriverSync - Couldn't aquire RemoveLock"));
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}
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return status;
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}
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/************************************************************************/
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/* CallLowerDriverSyncCompletion */
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/************************************************************************/
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//
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// Routine Description:
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//
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// This is the completion routine for CallLowerDriverSync() that
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// simply signals the event and stops the IRP completion from
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// unwinding so that CallLowerDriverSync() can regain ownership
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// of the IRP.
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//
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// Arguments:
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//
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// DevObjOrNULL - Usually, this is this driver's device object.
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// However, if this driver created the IRP, then
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// there is no stack location in the IRP for this
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// driver; so the kernel has no place to store the
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// device object; ** so devObj will be NULL in
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// this case **.
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// Irp - pointer to request
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//
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// Return Value:
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//
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// NTSTATUS
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//
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/************************************************************************/
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NTSTATUS
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CallLowerDriverSyncCompletion(
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IN PDEVICE_OBJECT DevObjOrNULL,
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IN PIRP Irp,
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IN PVOID Context
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)
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{
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PKEVENT event = Context;
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UNREFERENCED_PARAMETER( DevObjOrNULL );
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UNREFERENCED_PARAMETER( Irp );
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KeSetEvent(event, 0, FALSE);
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return STATUS_MORE_PROCESSING_REQUIRED;
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}
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