charfilterdevice.cpp

windows 2000/XP WDM设备驱动程序开发 附书光盘 武安河著

// CharFilterDevice.cpp
// Implementation of CharFilterDevice device class
//
// Generated by DriverWizard version DriverStudio 3.1.0 (Build 1722)
// Requires Compuware's DriverWorks classes
//

#include <vdw.h>
#include <Kwdmfltr.cpp>
#include "CharFilterDevice.h"

#include "..\CharSampleioctl.h"



////////////////////////////////////////////////////////////////////////
//  CharFilterDevice::CharFilterDevice
//
//	Routine Description:
//		This is the constructor for the Filter Device Object.
//		It is derived from KWdmFilterDevice, which builds in automatic
//	    dispatching of subfunctions of IRP_MJ_POWER and IRP_MJ_PNP to
//		virtual member functions.
//
//	Parameters:
//		Pdo - Physical Device Object - this is a pointer to a system
//			device object that represents the physical device.
//
//		Unit - Unit number. This is a number to append to the device's
//			base device name to form the Logical Device Object's name
//
//	Return Value:
//		None   
//
//	Comments:
//		The object being constructed contains a data member (m_Lower) of type
//		KPnpLowerDevice. By initializing it, the driver binds the Filter 
//		Device Object to the device stack.
//
CharFilterDevice::CharFilterDevice(PDEVICE_OBJECT Pdo, ULONG Unit) :
	KWdmFilterDevice(Pdo, NULL)
{

	// Check constructor status
    if ( !NT_SUCCESS(m_ConstructorStatus) )
	{
	    return;
	}

	// Remember our unit number
	m_Unit = Unit;

	// Initialize the lower device
	m_Lower.Initialize(this, Pdo);

	// Attach the filter
	NTSTATUS status = AttachFilter(&m_Lower); 

	// Check the status
	if ( !NT_SUCCESS(status) )
	{
		m_ConstructorStatus = status;
		return;
	}

	// Initialize the Filter Power Policy settings 
	SetFilterPowerPolicy();

	// Initialize the Filter PnP Policy settings 
	SetFilterPnpPolicy();
}


NTSTATUS CharFilterDevice::DeviceControl(KIrp I) 
{
	switch (I.IoctlCode())
	{
		case CHARSAMPLE_IOCTL_800:
		{
			READ_COMPLETION_INFO* pCompInfo =
				new (NonPagedPool) READ_COMPLETION_INFO;
			//创建一个READ_COMPLETION_INFO结构对象

			if ( pCompInfo == NULL )
			{
				return STATUS_INSUFFICIENT_RESOURCES;
			}

			RtlZeroMemory(pCompInfo,sizeof(READ_COMPLETION_INFO));//清0处理

			//设置结构对象中的参数，同CharFilter中的完全一样
			pCompInfo->m_pClass = this;

			pCompInfo->nin=I.IoctlInputBufferSize();
			pCompInfo->cin=new (NonPagedPool) CHAR[pCompInfo->nin];
			if ( pCompInfo->cin == NULL )
			{
				delete pCompInfo;
				return STATUS_INSUFFICIENT_RESOURCES;
			}

			pCompInfo->nout=I.IoctlOutputBufferSize();
			pCompInfo->cout=new (NonPagedPool) CHAR[pCompInfo->nout];
			if ( pCompInfo->cout == NULL )
			{
				delete pCompInfo->cin;
				delete pCompInfo;
				return STATUS_INSUFFICIENT_RESOURCES;
			}
			strncpy(pCompInfo->cin,(PCHAR)I.IoctlBuffer(),pCompInfo->nin);
			I.FileObject()->FsContext = pCompInfo;
			//将该结构对象地址指针放在I.FileObject()->FsContext中
			return PassThrough(I, LinkTo(IrpCompletionRoutine), this);
		}
		default:
			// Unrecognized IOCTL request
			return PassThrough(I);
	}
}
NTSTATUS CharFilterDevice::IrpCompletionRoutine(KIrp I)
{
	READ_COMPLETION_INFO* pCompInfo = 
		(READ_COMPLETION_INFO*)I.FileObject()->FsContext;
	if ( pCompInfo == NULL ) return I.Status();
	//构造一个结构对象，地址指向DeviceControl中创建的结构对象

	//IrpCompletionRoutine处理，同CharFilter中的完全一样
	strncpy(pCompInfo->cout,(PCHAR)I.IoctlBuffer(),2);
	pCompInfo->cout += 2;
	pCompInfo->nin  -= 1;
 	if (pCompInfo->nin == 0)
	{
		pCompInfo->cout -= pCompInfo->nout;
		strncpy((PCHAR)I.IoctlBuffer(),pCompInfo->cout,pCompInfo->nout);
		I.Information() = pCompInfo->nout;
		if (pCompInfo->cout) delete pCompInfo->cout;
		pCompInfo->cin -= (pCompInfo->nout - 2)/2;
		if (pCompInfo->cin) delete pCompInfo->cin;
		if (pCompInfo) delete pCompInfo;
		I.FileObject()->FsContext = NULL;
		return I.Status();
	}
	else
	{
		pCompInfo->cin++;
		strncpy((PCHAR)I.IoctlBuffer(),pCompInfo->cin,1);
		PassThrough(I, LinkTo(IrpCompletionRoutine), this);
		return STATUS_MORE_PROCESSING_REQUIRED;
	}
}