readwrite.cpp

Programming the Microsoft Windows driver model.2nd 随书光盘。内有很多作者送的实用工具和随书源码。WDM编程

// Read/Write request processors for feature driver
// Copyright (C) 1999 by Walter Oney
// All rights reserved

#include "stddcls.h"
#include "driver.h"

#if DBG
	#define MSGUSBSTRING(d,s,i) { \
		UNICODE_STRING sd; \
		if (i && NT_SUCCESS(GetStringDescriptor(d,i,&sd))) { \
			DbgPrint(s, sd.Buffer); \
			RtlFreeUnicodeString(&sd); \
		}}
#else
	#define MSGUSBSTRING(d,i,s)
#endif

///////////////////////////////////////////////////////////////////////////////

#pragma PAGEDCODE

NTSTATUS DispatchCreate(PDEVICE_OBJECT fdo, PIRP Irp)
	{							// DispatchCreate
	PAGED_CODE();
	KdPrint((DRIVERNAME " - IRP_MJ_CREATE\n"));
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;

	PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(Irp);

	NTSTATUS status = STATUS_SUCCESS;
	InterlockedIncrement(&pdx->handles);
	return CompleteRequest(Irp, status, 0);
	}							// DispatchCreate

///////////////////////////////////////////////////////////////////////////////

#pragma PAGEDCODE

NTSTATUS DispatchClose(PDEVICE_OBJECT fdo, PIRP Irp)
	{							// DispatchClose
	PAGED_CODE();
	KdPrint((DRIVERNAME " - IRP_MJ_CLOSE\n"));
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;
	PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(Irp);
	InterlockedDecrement(&pdx->handles);
	return CompleteRequest(Irp, STATUS_SUCCESS, 0);
	}							// DispatchClose

///////////////////////////////////////////////////////////////////////////////

#pragma PAGEDCODE

NTSTATUS GetStringDescriptor(PDEVICE_OBJECT fdo, UCHAR istring, PUNICODE_STRING s)
	{							// GetStringDescriptor
	NTSTATUS status;
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;
	URB urb;

	UCHAR data[256];			// maximum-length buffer

	// If this is the first time here, read string descriptor zero and arbitrarily select
	// the first language identifer as the one to use in subsequent get-descriptor calls.

	if (!pdx->langid)
		{						// determine default language id
		UsbBuildGetDescriptorRequest(&urb, sizeof(_URB_CONTROL_DESCRIPTOR_REQUEST), USB_STRING_DESCRIPTOR_TYPE,
			0, 0, data, NULL, sizeof(data), NULL);
		status = SendAwaitUrb(fdo, &urb);
		if (!NT_SUCCESS(status))
			return status;
		pdx->langid = *(LANGID*)(data + 2);
		}						// determine default language id

	// Fetch the designated string descriptor.

	UsbBuildGetDescriptorRequest(&urb, sizeof(_URB_CONTROL_DESCRIPTOR_REQUEST), USB_STRING_DESCRIPTOR_TYPE,
		istring, pdx->langid, data, NULL, sizeof(data), NULL);
	status = SendAwaitUrb(fdo, &urb);
	if (!NT_SUCCESS(status))
		return status;

	ULONG nchars = (data[0] - sizeof(WCHAR)) / sizeof(WCHAR);
	if (nchars > 127)
		nchars = 127;
	PWSTR p = (PWSTR) ExAllocatePool(PagedPool, (nchars + 1) * sizeof(WCHAR));
	if (!p)
		return STATUS_INSUFFICIENT_RESOURCES;

	memcpy(p, data + 2, nchars * sizeof(WCHAR));
	p[nchars] = 0;

	s->Length = (USHORT) (sizeof(WCHAR) * nchars);
	s->MaximumLength = (USHORT) ((sizeof(WCHAR) * nchars) + sizeof(WCHAR));
	s->Buffer = p;

	return STATUS_SUCCESS;
	}							// GetStringDescriptor

///////////////////////////////////////////////////////////////////////////////

#pragma PAGEDCODE

NTSTATUS SendAwaitUrb(PDEVICE_OBJECT fdo, PURB urb)
	{							// SendAwaitUrb
	PAGED_CODE();
	ASSERT(KeGetCurrentIrql() == PASSIVE_LEVEL);
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;

	KEVENT event;
	KeInitializeEvent(&event, NotificationEvent, FALSE);

	IO_STATUS_BLOCK iostatus;
	PIRP Irp = IoBuildDeviceIoControlRequest(IOCTL_INTERNAL_USB_SUBMIT_URB,
		pdx->LowerDeviceObject, NULL, 0, NULL, 0, TRUE, &event, &iostatus);

	if (!Irp)
		{
		KdPrint((DRIVERNAME " - Unable to allocate IRP for sending URB\n"));
		return STATUS_INSUFFICIENT_RESOURCES;
		}

	PIO_STACK_LOCATION stack = IoGetNextIrpStackLocation(Irp);
	stack->Parameters.Others.Argument1 = (PVOID) urb;
	NTSTATUS status = IoCallDriver(pdx->LowerDeviceObject, Irp);
	if (status == STATUS_PENDING)
		{
		KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL);
		status = iostatus.Status;
		}
	return status;
	}							// SendAwaitUrb

///////////////////////////////////////////////////////////////////////////////

#pragma PAGEDCODE

NTSTATUS StartDevice(PDEVICE_OBJECT fdo, PCM_PARTIAL_RESOURCE_LIST raw, PCM_PARTIAL_RESOURCE_LIST translated)
	{							// StartDevice
	PAGED_CODE();
	NTSTATUS status;
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;

	URB urb;					// URB for use in this subroutine

	// Read our device descriptor. The only real purpose to this would be to find out how many
	// configurations there are so we can read their descriptors. In this simplest of examples,
	// there's only one configuration.

	UsbBuildGetDescriptorRequest(&urb, sizeof(_URB_CONTROL_DESCRIPTOR_REQUEST), USB_DEVICE_DESCRIPTOR_TYPE,
		0, 0, &pdx->dd, NULL, sizeof(pdx->dd), NULL);
	status = SendAwaitUrb(fdo, &urb);
	if (!NT_SUCCESS(status))
		{
		KdPrint((DRIVERNAME " - Error %X trying to read device descriptor\n", status));
		return status;
		}

	MSGUSBSTRING(fdo, DRIVERNAME " - Configuring device from %ws\n", pdx->dd.iManufacturer);
	MSGUSBSTRING(fdo, DRIVERNAME " - Product is %ws\n", pdx->dd.iProduct);
	MSGUSBSTRING(fdo, DRIVERNAME " - Serial number is %ws\n", pdx->dd.iSerialNumber);

	// Read the descriptor of the first configuration. This requires two steps. The first step
	// reads the fixed-size configuration descriptor alone. The second step reads the
	// configuration descriptor plus all imbedded interface and endpoint descriptors.

	USB_CONFIGURATION_DESCRIPTOR tcd;
	UsbBuildGetDescriptorRequest(&urb, sizeof(_URB_CONTROL_DESCRIPTOR_REQUEST), USB_CONFIGURATION_DESCRIPTOR_TYPE,
		0, 0, &tcd, NULL, sizeof(tcd), NULL);
	status = SendAwaitUrb(fdo, &urb);
	if (!NT_SUCCESS(status))
		{
		KdPrint((DRIVERNAME " - Error %X trying to read configuration descriptor 1\n", status));
		return status;
		}

	ULONG size = tcd.wTotalLength;
	PUSB_CONFIGURATION_DESCRIPTOR pcd = (PUSB_CONFIGURATION_DESCRIPTOR) ExAllocatePool(NonPagedPool, size);
	if (!pcd)
		{
		KdPrint((DRIVERNAME " - Unable to allocate %X bytes for configuration descriptor\n", size));
		return STATUS_INSUFFICIENT_RESOURCES;
		}

	__try
		{
		UsbBuildGetDescriptorRequest(&urb, sizeof(_URB_CONTROL_DESCRIPTOR_REQUEST), USB_CONFIGURATION_DESCRIPTOR_TYPE,
			0, 0, pcd, NULL, size, NULL);
		status = SendAwaitUrb(fdo, &urb);
		if (!NT_SUCCESS(status))
			{
			KdPrint((DRIVERNAME " - Error %X trying to read configuration descriptor 1\n", status));
			return status;
			}
                                   
		MSGUSBSTRING(fdo, DRIVERNAME " - Selecting configuration named %ws\n", pcd->iConfiguration);

		// Locate the descriptor for the one and only interface we expect to find

		PUSB_INTERFACE_DESCRIPTOR pid = USBD_ParseConfigurationDescriptorEx(pcd, pcd,
			-1, -1, -1, -1, -1);
		ASSERT(pid);
                                   
		MSGUSBSTRING(fdo, DRIVERNAME " - Selecting interface named %ws\n", pid->iInterface);

		// Create a URB to use in selecting a configuration.

		USBD_INTERFACE_LIST_ENTRY interfaces[2] = {
			{pid, NULL},
			{NULL, NULL},		// fence to terminate the array
			};

		PURB selurb = USBD_CreateConfigurationRequestEx(pcd, interfaces);
		if (!selurb)
			{
			KdPrint((DRIVERNAME " - Unable to create configuration request\n"));
			return STATUS_INSUFFICIENT_RESOURCES;
			}

		__try
			{

			// Verify that the interface describes exactly the endpoints we expect

			if (pid->bNumEndpoints != 0)
				{
				KdPrint((DRIVERNAME " - %d is the wrong number of endpoints\n", pid->bNumEndpoints));
				return STATUS_DEVICE_CONFIGURATION_ERROR;
				}

			PUSBD_INTERFACE_INFORMATION pii = interfaces[0].Interface;
			ASSERT(pii->NumberOfPipes == pid->bNumEndpoints);

			// Submit the set-configuration request

			status = SendAwaitUrb(fdo, selurb);
			if (!NT_SUCCESS(status))
				{
				KdPrint((DRIVERNAME " - Error %X trying to select configuration\n", status));
				return status;
				}

			// Save the configuration and pipe handles

			pdx->hconfig = selurb->UrbSelectConfiguration.ConfigurationHandle;

			// Transfer ownership of the configuration descriptor to the device extension
			
			pdx->pcd = pcd;
			pcd = NULL;
			}
		__finally
			{
			ExFreePool(selurb);
			}

		}
	__finally
		{
		if (pcd)
			ExFreePool(pcd);
		}

	return STATUS_SUCCESS;
	}							// StartDevice

///////////////////////////////////////////////////////////////////////////////

#pragma PAGEDCODE

VOID StopDevice(IN PDEVICE_OBJECT fdo, BOOLEAN oktouch /* = FALSE */)
	{							// StopDevice
	PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;

	// If it's okay to touch our hardware (i.e., we're processing an IRP_MN_STOP_DEVICE),
	// deconfigure the device.
	
	if (oktouch)
		{						// deconfigure device
		URB urb;
		UsbBuildSelectConfigurationRequest(&urb, sizeof(_URB_SELECT_CONFIGURATION), NULL);
		NTSTATUS status = SendAwaitUrb(fdo, &urb);
		if (!NT_SUCCESS(status))
			KdPrint((DRIVERNAME " - Error %X trying to deconfigure device\n", status));
		}						// deconfigure device

	if (pdx->pcd)
		ExFreePool(pdx->pcd);
	pdx->pcd = NULL;
	}							// StopDevice