回顾驱动与用户层通信-原创手记-慕课网

环境:win10 64位

先关签名有时这样不行得去恢复高级选项那禁止强制签名重启

bcdedit.exe /set nointegritychecks on

1。缓冲区方式读写

桥梁是用一个buf

将数据存储在AssociatedIrp.SystemBuffer

pDevObj->Flags |= DO_BUFFERED_IO

用户层

main.cpp

#include <windows.h>

#include <stdio.h>

#define GetFilePointer(hFile) SetFilePointer(hFile, 0, NULL, FILE_CURRENT)

int main()

{

HANDLE hDevice =

CreateFile("\\\\.\\HelloDDK",

GENERIC_READ | GENERIC_WRITE,

0, // share mode none

NULL, // no security

OPEN_EXISTING,

FILE_ATTRIBUTE_NORMAL,

NULL); // no template

if (hDevice == INVALID_HANDLE_VALUE)

{

printf("Failed to obtain file handle to device: "

"%s with Win32 error code: %d\n",

"MyWDMDevice", GetLastError());

//return 1;

}

UCHAR buffer[10];

memset(buffer, 0xBB, 10);

ULONG ulRead;

ULONG ulWrite;

BOOL bRet;

bRet = WriteFile(hDevice, buffer, 10, &ulWrite, NULL);

if (bRet)

{

printf("Write %d bytes\n", ulWrite);

}

bRet = ReadFile(hDevice, buffer, 10, &ulRead, NULL);

if (bRet)

{

printf("Read %d bytes:", ulRead);

for (int i = 0; i<(int)ulRead; i++)

{

printf("%02X ", buffer[i]);

}

printf("\n");

}

printf("file length:%d\n", GetFileSize(hDevice, NULL));

CloseHandle(hDevice);

getchar();

return 0;

}

驱动层

test.c

#include "Driver.h"

/************************************************************************

* 函数名称:DriverEntry

* 功能描述:初始化驱动程序，定位和申请硬件资源，创建内核对象

* 参数列表:

pDriverObject:从I/O管理器中传进来的驱动对象

pRegistryPath:驱动程序在注册表的中的路径

* 返回值:返回初始化驱动状态

*************************************************************************/

#pragma INITCODE

NTSTATUS DriverEntry(

IN PDRIVER_OBJECT pDriverObject,

IN PUNICODE_STRING pRegistryPath)

{

NTSTATUS status;

KdPrint(("Enter DriverEntry\n"));

//设置卸载函数

pDriverObject->DriverUnload = HelloDDKUnload;

//设置派遣函数

for (int i = 0; i < arraysize(pDriverObject->MajorFunction); ++i)

pDriverObject->MajorFunction[i] = HelloDDKDispatchRoutin;

pDriverObject->MajorFunction[IRP_MJ_WRITE] = HelloDDWrite;

pDriverObject->MajorFunction[IRP_MJ_READ] = HelloDDKRead;

//用户层获取文件长度时用产生这个irp

pDriverObject->MajorFunction[IRP_MJ_QUERY_INFORMATION] = HelloDDKQueryInfomation;

//创建驱动设备对象

status = CreateDevice(pDriverObject);

KdPrint(("Leave DriverEntry\n"));

return status;

}

/************************************************************************

* 函数名称:CreateDevice

* 功能描述:初始化设备对象

* 参数列表:

pDriverObject:从I/O管理器中传进来的驱动对象

* 返回值:返回初始化状态

*************************************************************************/

#pragma INITCODE

NTSTATUS CreateDevice(

IN PDRIVER_OBJECT pDriverObject)

{

NTSTATUS status;

PDEVICE_OBJECT pDevObj;

PDEVICE_EXTENSION pDevExt;

//创建设备名称

UNICODE_STRING devName;

RtlInitUnicodeString(&devName, L"\\Device\\MyDDKDevice");

//创建设备

status = IoCreateDevice(pDriverObject,

sizeof(DEVICE_EXTENSION),

&devName,

FILE_DEVICE_UNKNOWN,

0, TRUE,

&pDevObj);

if (!NT_SUCCESS(status))

return status;

pDevObj->Flags |= DO_BUFFERED_IO;

pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;

pDevExt->pDevice = pDevObj;

pDevExt->ustrDeviceName = devName;

//申请模拟文件的缓冲区

pDevExt->buffer = (PUCHAR)ExAllocatePool(PagedPool, MAX_FILE_LENGTH);

//设置模拟文件大小

pDevExt->file_length = 0;

//创建符号链接

UNICODE_STRING symLinkName;

RtlInitUnicodeString(&symLinkName, L"\\??\\HelloDDK");

pDevExt->ustrSymLinkName = symLinkName;

status = IoCreateSymbolicLink(&symLinkName, &devName);

if (!NT_SUCCESS(status))

{

IoDeleteDevice(pDevObj);

return status;

}

return STATUS_SUCCESS;

}

/************************************************************************

* 函数名称:HelloDDKUnload

* 功能描述:负责驱动程序的卸载操作

* 参数列表:

pDriverObject:驱动对象

* 返回值:返回状态

*************************************************************************/

#pragma PAGEDCODE

VOID HelloDDKUnload(IN PDRIVER_OBJECT pDriverObject)

{

PDEVICE_OBJECT pNextObj;

KdPrint(("Enter DriverUnload\n"));

pNextObj = pDriverObject->DeviceObject;

while (pNextObj != NULL)

{

PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)

pNextObj->DeviceExtension;

if (pDevExt->buffer)

{

ExFreePool(pDevExt->buffer);

pDevExt->buffer = NULL;

}

//删除符号链接

UNICODE_STRING pLinkName = pDevExt->ustrSymLinkName;

IoDeleteSymbolicLink(&pLinkName);

pNextObj = pNextObj->NextDevice;

IoDeleteDevice(pDevExt->pDevice);

}

/************************************************************************

* 函数名称:HelloDDKDispatchRoutin

* 功能描述:对读IRP进行处理

* 参数列表:

pDevObj:功能设备对象

pIrp:从IO请求包

* 返回值:返回状态

*************************************************************************/

#pragma PAGEDCODE

NTSTATUS HelloDDKDispatchRoutin(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp)

{

KdPrint(("Enter HelloDDKDispatchRoutin\n"));

PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(pIrp);

//建立一个字符串数组与IRP类型对应起来

static char* irpname[] =

{

"IRP_MJ_CREATE",

"IRP_MJ_CREATE_NAMED_PIPE",

"IRP_MJ_CLOSE",

"IRP_MJ_READ",

"IRP_MJ_WRITE",

"IRP_MJ_QUERY_INFORMATION",

"IRP_MJ_SET_INFORMATION",

"IRP_MJ_QUERY_EA",

"IRP_MJ_SET_EA",

"IRP_MJ_FLUSH_BUFFERS",

"IRP_MJ_QUERY_VOLUME_INFORMATION",

"IRP_MJ_SET_VOLUME_INFORMATION",

"IRP_MJ_DIRECTORY_CONTROL",

"IRP_MJ_FILE_SYSTEM_CONTROL",

"IRP_MJ_DEVICE_CONTROL",

"IRP_MJ_INTERNAL_DEVICE_CONTROL",

"IRP_MJ_SHUTDOWN",

"IRP_MJ_LOCK_CONTROL",

"IRP_MJ_CLEANUP",

"IRP_MJ_CREATE_MAILSLOT",

"IRP_MJ_QUERY_SECURITY",

"IRP_MJ_SET_SECURITY",

"IRP_MJ_POWER",

"IRP_MJ_SYSTEM_CONTROL",

"IRP_MJ_DEVICE_CHANGE",

"IRP_MJ_QUERY_QUOTA",

"IRP_MJ_SET_QUOTA",

"IRP_MJ_PNP",

};

UCHAR type = stack->MajorFunction;

if (type >= arraysize(irpname))

KdPrint((" - Unknown IRP, major type %X\n", type));

else

KdPrint(("\t%s\n", irpname[type]));

//对一般IRP的简单操作，后面会介绍对IRP更复杂的操作

NTSTATUS status = STATUS_SUCCESS;

// 完成IRP

pIrp->IoStatus.Status = status;

pIrp->IoStatus.Information = 0; // bytes xfered

IoCompleteRequest(pIrp, IO_NO_INCREMENT);

KdPrint(("Leave HelloDDKDispatchRoutin\n"));

return status;

}

NTSTATUS HelloDDKRead(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp)

{

KdPrint(("Enter HelloDDKRead\n"));

//在 IoCreateDevice申请模拟文件的缓冲区

//pDevExt->buffer = (PUCHAR)ExAllocatePool(PagedPool, MAX_FILE_LENGTH);

PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;

NTSTATUS status = STATUS_SUCCESS;

PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(pIrp);

ULONG ulReadLength = stack->Parameters.Read.Length;

ULONG ulReadOffset = (ULONG)stack->Parameters.Read.ByteOffset.QuadPart;

if (ulReadOffset + ulReadLength>MAX_FILE_LENGTH)

{

status = STATUS_FILE_INVALID;

ulReadLength = 0;

}

else

{

//将数据存储在AssociatedIrp.SystemBuffer，以便应用程序使用

memcpy(pIrp->AssociatedIrp.SystemBuffer, pDevExt->buffer + ulReadOffset, ulReadLength);

status = STATUS_SUCCESS;

}

pIrp->IoStatus.Status = status;

pIrp->IoStatus.Information = ulReadLength; // bytes xfered

IoCompleteRequest(pIrp, IO_NO_INCREMENT);

KdPrint(("Leave HelloDDKRead\n"));

return status;

}

NTSTATUS HelloDDWrite(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp)

{

KdPrint(("Enter HelloDDWrite\n"));

NTSTATUS status = STATUS_SUCCESS;

//在 IoCreateDevice申请模拟文件的缓冲区

//pDevExt->buffer = (PUCHAR)ExAllocatePool(PagedPool, MAX_FILE_LENGTH);

PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;

PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(pIrp);

//获取存储的长度

ULONG ulWriteLength = stack->Parameters.Write.Length;

//获取存储的偏移量就是buffer中从哪里开始

ULONG ulWriteOffset = (ULONG)stack->Parameters.Write.ByteOffset.QuadPart;

if (ulWriteOffset + ulWriteLength>MAX_FILE_LENGTH)

{

//如果存储长度+偏移量大于缓冲区长度，则返回无效

status = STATUS_FILE_INVALID;

ulWriteLength = 0;

}

else

{

//将写入的数据，存储在缓冲区内

memcpy(pDevExt->buffer + ulWriteOffset, pIrp->AssociatedIrp.SystemBuffer, ulWriteLength);

status = STATUS_SUCCESS;

//设置新的文件长度

if (ulWriteLength + ulWriteOffset>pDevExt->file_length)

{

pDevExt->file_length = ulWriteLength + ulWriteOffset;

}

pIrp->IoStatus.Status = status;

//用户的返回值是这个

pIrp->IoStatus.Information = ulWriteLength; // bytes xfered

IoCompleteRequest(pIrp, IO_NO_INCREMENT);

KdPrint(("Leave HelloDDWrite\n"));

return status;

}

NTSTATUS HelloDDKQueryInfomation(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp)

{

KdPrint(("Enter HelloDDKQueryInfomation\n"));

PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(pIrp);

PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;

FILE_INFORMATION_CLASS info = stack->Parameters.QueryFile.FileInformationClass;

if (info == FileStandardInformation)

{

KdPrint(("FileStandardInformation\n"));

PFILE_STANDARD_INFORMATION file_info =

(PFILE_STANDARD_INFORMATION)pIrp->AssociatedIrp.SystemBuffer;

file_info->EndOfFile = RtlConvertLongToLargeInteger(pDevExt->file_length);

}

NTSTATUS status = STATUS_SUCCESS;

// 完成IRP

pIrp->IoStatus.Status = status;

pIrp->IoStatus.Information = stack->Parameters.QueryFile.Length; // bytes xfered

IoCompleteRequest(pIrp, IO_NO_INCREMENT);

KdPrint(("Leave HelloDDKQueryInfomation\n"));

return status;

}

//Driver.h

#pragma once

#ifdef __cplusplus

extern "C"

{

#endif

#include <NTDDK.h>

#ifdef __cplusplus

}

#endif

#define PAGEDCODE code_seg("PAGE")

#define LOCKEDCODE code_seg()

#define INITCODE code_seg("INIT")

#define PAGEDDATA data_seg("PAGE")

#define LOCKEDDATA data_seg()

#define INITDATA data_seg("INIT")

#define arraysize(p) (sizeof(p)/sizeof((p)[0]))

#define MAX_FILE_LENGTH 1024

typedef struct _DEVICE_EXTENSION {

PDEVICE_OBJECT pDevice;

UNICODE_STRING ustrDeviceName; //设备名称

UNICODE_STRING ustrSymLinkName; //符号链接名

PUCHAR buffer;//缓冲区

ULONG file_length;//模拟的文件长度，必须小于MAX_FILE_LENGTH

} DEVICE_EXTENSION, *PDEVICE_EXTENSION;

// 函数声明

NTSTATUS CreateDevice(IN PDRIVER_OBJECT pDriverObject);

VOID HelloDDKUnload(IN PDRIVER_OBJECT pDriverObject);

NTSTATUS HelloDDKDispatchRoutin(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

NTSTATUS HelloDDKRead(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

NTSTATUS HelloDDWrite(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

NTSTATUS HelloDDKQueryInfomation(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

回顾驱动与用户层通信

2。直接方式

pDevObj->Flags |= DO_DIRECT_IO;

用户层

main.cpp

#include <windows.h>

#include <stdio.h>

#define GetFilePointer(hFile) SetFilePointer(hFile, 0, NULL, FILE_CURRENT)

int main()

{

HANDLE hDevice =

CreateFile("\\\\.\\HelloDDK",

GENERIC_READ | GENERIC_WRITE,

0, // share mode none

NULL, // no security

OPEN_EXISTING,

FILE_ATTRIBUTE_NORMAL,

NULL ); // no template

if (hDevice == INVALID_HANDLE_VALUE)

{

printf("Failed to obtain file handle to device: "

"%s with Win32 error code: %d\n",

"MyWDMDevice", GetLastError() );

return 1;

}

UCHAR buffer[10];

memset(buffer,0xBB,10);

ULONG ulRead;

BOOL bRet;

bRet = ReadFile(hDevice,buffer,10,&ulRead,NULL);

if (bRet)

{

printf("Address 0X%08X\n",buffer);

printf("(Read %d bytes):",ulRead);

for (int i=0;i<(int)ulRead;i++)

{

printf("%02X ",buffer[i]);

}

printf("\n");

}

CloseHandle(hDevice);

return 0;

}

驱动层

test.c

#include "Driver.h"

/************************************************************************

* 函数名称:DriverEntry

* 功能描述:初始化驱动程序，定位和申请硬件资源，创建内核对象

* 参数列表:

pDriverObject:从I/O管理器中传进来的驱动对象

pRegistryPath:驱动程序在注册表的中的路径

* 返回值:返回初始化驱动状态

*************************************************************************/

#pragma INITCODE

NTSTATUS DriverEntry (

IN PDRIVER_OBJECT pDriverObject,

IN PUNICODE_STRING pRegistryPath )

{

NTSTATUS status;

KdPrint(("Enter DriverEntry\n"));

//设置卸载函数

pDriverObject->DriverUnload = HelloDDKUnload;

//设置派遣函数

for (int i = 0; i < arraysize(pDriverObject->MajorFunction); ++i)

pDriverObject->MajorFunction[i] = HelloDDKDispatchRoutin;

pDriverObject->MajorFunction[IRP_MJ_READ] = HelloDDKRead;

//创建驱动设备对象

status = CreateDevice(pDriverObject);

KdPrint(("Leave DriverEntry\n"));

return status;

}

/************************************************************************

* 函数名称:CreateDevice

* 功能描述:初始化设备对象

* 参数列表:

pDriverObject:从I/O管理器中传进来的驱动对象

* 返回值:返回初始化状态

*************************************************************************/

#pragma INITCODE

NTSTATUS CreateDevice (

IN PDRIVER_OBJECT pDriverObject)

{

NTSTATUS status;

PDEVICE_OBJECT pDevObj;

PDEVICE_EXTENSION pDevExt;

//创建设备名称

UNICODE_STRING devName;

RtlInitUnicodeString(&devName,L"\\Device\\MyDDKDevice");

//创建设备

status = IoCreateDevice( pDriverObject,

sizeof(DEVICE_EXTENSION),

&(UNICODE_STRING)devName,

FILE_DEVICE_UNKNOWN,

0, TRUE,

&pDevObj );

if (!NT_SUCCESS(status))

return status;

pDevObj->Flags |= DO_DIRECT_IO;

pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;

pDevExt->pDevice = pDevObj;

pDevExt->ustrDeviceName = devName;

//申请模拟文件的缓冲区

pDevExt->buffer = (PUCHAR)ExAllocatePool(PagedPool,MAX_FILE_LENGTH);

//设置模拟文件大小

pDevExt->file_length = 0;

//创建符号链接

UNICODE_STRING symLinkName;

RtlInitUnicodeString(&symLinkName,L"\\??\\HelloDDK");

pDevExt->ustrSymLinkName = symLinkName;

status = IoCreateSymbolicLink( &symLinkName,&devName );

if (!NT_SUCCESS(status))

{

IoDeleteDevice( pDevObj );

return status;

}

return STATUS_SUCCESS;

}

/************************************************************************

* 函数名称:HelloDDKUnload

* 功能描述:负责驱动程序的卸载操作

* 参数列表:

pDriverObject:驱动对象

* 返回值:返回状态

*************************************************************************/

#pragma PAGEDCODE

VOID HelloDDKUnload (IN PDRIVER_OBJECT pDriverObject)

{

PDEVICE_OBJECT pNextObj;

KdPrint(("Enter DriverUnload\n"));

pNextObj = pDriverObject->DeviceObject;

while (pNextObj != NULL)

{

PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)

pNextObj->DeviceExtension;

if (pDevExt->buffer)

{

ExFreePool(pDevExt->buffer);

pDevExt->buffer = NULL;

}

//删除符号链接

UNICODE_STRING pLinkName = pDevExt->ustrSymLinkName;

IoDeleteSymbolicLink(&pLinkName);

pNextObj = pNextObj->NextDevice;

IoDeleteDevice( pDevExt->pDevice );

}

/************************************************************************

* 函数名称:HelloDDKDispatchRoutin

* 功能描述:对读IRP进行处理

* 参数列表:

pDevObj:功能设备对象

pIrp:从IO请求包

* 返回值:返回状态

*************************************************************************/

#pragma PAGEDCODE

NTSTATUS HelloDDKDispatchRoutin(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp)

{

KdPrint(("Enter HelloDDKDispatchRoutin\n"));

PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(pIrp);

//建立一个字符串数组与IRP类型对应起来

static char* irpname[] =

{

"IRP_MJ_CREATE",

"IRP_MJ_CREATE_NAMED_PIPE",

"IRP_MJ_CLOSE",

"IRP_MJ_READ",

"IRP_MJ_WRITE",

"IRP_MJ_QUERY_INFORMATION",

"IRP_MJ_SET_INFORMATION",

"IRP_MJ_QUERY_EA",

"IRP_MJ_SET_EA",

"IRP_MJ_FLUSH_BUFFERS",

"IRP_MJ_QUERY_VOLUME_INFORMATION",

"IRP_MJ_SET_VOLUME_INFORMATION",

"IRP_MJ_DIRECTORY_CONTROL",

"IRP_MJ_FILE_SYSTEM_CONTROL",

"IRP_MJ_DEVICE_CONTROL",

"IRP_MJ_INTERNAL_DEVICE_CONTROL",

"IRP_MJ_SHUTDOWN",

"IRP_MJ_LOCK_CONTROL",

"IRP_MJ_CLEANUP",

"IRP_MJ_CREATE_MAILSLOT",

"IRP_MJ_QUERY_SECURITY",

"IRP_MJ_SET_SECURITY",

"IRP_MJ_POWER",

"IRP_MJ_SYSTEM_CONTROL",

"IRP_MJ_DEVICE_CHANGE",

"IRP_MJ_QUERY_QUOTA",

"IRP_MJ_SET_QUOTA",

"IRP_MJ_PNP",

};

UCHAR type = stack->MajorFunction;

if (type >= arraysize(irpname))

KdPrint((" - Unknown IRP, major type %X\n", type));

else

KdPrint(("\t%s\n", irpname[type]));

NTSTATUS status = STATUS_SUCCESS;

// 完成IRP

pIrp->IoStatus.Status = status;

pIrp->IoStatus.Information = 0; // bytes xfered

IoCompleteRequest( pIrp, IO_NO_INCREMENT );

KdPrint(("Leave HelloDDKDispatchRoutin\n"));

return status;

}

NTSTATUS HelloDDKRead(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp)

{

KdPrint(("Enter HelloDDKRead\n"));

PDEVICE_EXTENSION pDevExt = (PDEVICE_EXTENSION)pDevObj->DeviceExtension;

NTSTATUS status = STATUS_SUCCESS;

PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(pIrp);

ULONG ulReadLength = stack->Parameters.Read.Length;

KdPrint(("ulReadLength:%d\n",ulReadLength));

ULONG mdl_length = MmGetMdlByteCount(pIrp->MdlAddress);

PVOID mdl_address = MmGetMdlVirtualAddress(pIrp->MdlAddress);

ULONG mdl_offset = MmGetMdlByteOffset(pIrp->MdlAddress);

KdPrint(("mdl_address:0X%08X\n",mdl_address));

KdPrint(("mdl_length:%d\n",mdl_length));

KdPrint(("mdl_offset:%d\n",mdl_offset));

if (mdl_length!=ulReadLength)

{

//MDL的长度应该和读长度相等，否则该操作应该设为不成功

pIrp->IoStatus.Information = 0;

status = STATUS_UNSUCCESSFUL;

}else

{

//用MmGetSystemAddressForMdlSafe得到MDL在内核模式下的映射就是用户中的buffer映射

PVOID kernel_address = MmGetSystemAddressForMdlSafe(pIrp->MdlAddress,NormalPagePriority);

KdPrint(("kernel_address:0X%08X\n",kernel_address));

//修改数据

memset(kernel_address,0XAA,ulReadLength);

pIrp->IoStatus.Information = ulReadLength; // bytes xfered

}

pIrp->IoStatus.Status = status;

IoCompleteRequest( pIrp, IO_NO_INCREMENT );

KdPrint(("Leave HelloDDKRead\n"));

return status;

}

//Driver.h

/************************************************************************

* 文件名称:Driver.h

* 作者:张帆

* 完成日期:2007-11-1

*************************************************************************/

#pragma once

#ifdef __cplusplus

extern "C"

{

#endif

#include <NTDDK.h>

#ifdef __cplusplus

}

#endif

#define PAGEDCODE code_seg("PAGE")

#define LOCKEDCODE code_seg()

#define INITCODE code_seg("INIT")

#define PAGEDDATA data_seg("PAGE")

#define LOCKEDDATA data_seg()

#define INITDATA data_seg("INIT")

#define arraysize(p) (sizeof(p)/sizeof((p)[0]))

#define MAX_FILE_LENGTH 1024

typedef struct _DEVICE_EXTENSION {

PDEVICE_OBJECT pDevice;

UNICODE_STRING ustrDeviceName; //设备名称

UNICODE_STRING ustrSymLinkName; //符号链接名

PUCHAR buffer;//缓冲区

ULONG file_length;//模拟的文件长度，必须小于MAX_FILE_LENGTH

} DEVICE_EXTENSION, *PDEVICE_EXTENSION;

// 函数声明

NTSTATUS CreateDevice (IN PDRIVER_OBJECT pDriverObject);

VOID HelloDDKUnload (IN PDRIVER_OBJECT pDriverObject);

NTSTATUS HelloDDKDispatchRoutin(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

NTSTATUS HelloDDKRead(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

NTSTATUS HelloDDWrite(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);

NTSTATUS HelloDDKQueryInfomation(IN PDEVICE_OBJECT pDevObj,

IN PIRP pIrp);