c++ 如何进行驱动开发 请展示一个示例

C++进行驱动开发需要使用操作系统提供的驱动开发框架进行开发，这里以Windows操作系统为例，介绍一个简单的驱动开发示例：

1. 创建一个空的Win32控制台应用程序，将其命名为DriverTest。

2. 添加一个新的源文件，命名为DriverTest.cpp，并在其中添加以下代码：

#include <windows.h>
#include <stdio.h>

#define DEVICE_NAME L"\\\\.\\HelloWorld"
#define IOCTL_HELLO_WORLD CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_ANY_ACCESS)

HANDLE g_hDevice = INVALID_HANDLE_VALUE;

int main() {
    g_hDevice = CreateFile(DEVICE_NAME, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (g_hDevice == INVALID_HANDLE_VALUE) {
        printf("Failed to open device, error code: %d\n", GetLastError());
        return -1;
    }

    DWORD dwData = 0x12345678;
    DWORD dwBytesReturned = 0;
    BOOL bRet = DeviceIoControl(g_hDevice, IOCTL_HELLO_WORLD, &dwData, sizeof(dwData), &dwData, sizeof(dwData), &dwBytesReturned, NULL);
    if (!bRet) {
        printf("Failed to send IOCTL to device, error code: %d\n", GetLastError());
        return -1;
    }

    printf("Receive data from device: 0x%x\n", dwData);

    CloseHandle(g_hDevice);
    return 0;
}

3. 添加一个新的源文件，命名为DriverTestDriver.cpp，并在其中添加以下代码：

#include <ntddk.h>

#define DEVICE_NAME L"\\Device\\HelloWorld"
#define SYMBOLIC_NAME L"\\DosDevices\\HelloWorld"
#define IOCTL_HELLO_WORLD CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_ANY_ACCESS)

PDEVICE_OBJECT g_pDeviceObject = NULL;

NTSTATUS HelloWorldDispatchRoutine(PDEVICE_OBJECT pDeviceObject, PIRP pIrp) {
    NTSTATUS status = STATUS_SUCCESS;
    PIO_STACK_LOCATION pIrpStack = IoGetCurrentIrpStackLocation(pIrp);
    ULONG ulInputBufferLength = pIrpStack->Parameters.DeviceIoControl.InputBufferLength;
    ULONG ulOutputBufferLength = pIrpStack->Parameters.DeviceIoControl.OutputBufferLength;

    switch (pIrpStack->MajorFunction) {
    case IRP_MJ_CREATE:
    case IRP_MJ_CLOSE:
        break;
    case IRP_MJ_DEVICE_CONTROL:
        if (pIrpStack->Parameters.DeviceIoControl.IoControlCode == IOCTL_HELLO_WORLD) {
            if (ulInputBufferLength < sizeof(DWORD) || ulOutputBufferLength < sizeof(DWORD)) {
                status = STATUS_INVALID_PARAMETER;
                break;
            }

            PDWORD pInputData = (PDWORD)pIrp->AssociatedIrp.SystemBuffer;
            PDWORD pOutputData = (PDWORD)pIrp->AssociatedIrp.SystemBuffer;

            *pOutputData = *pInputData ^ 0xFFFFFFFF;

            pIrp->IoStatus.Information = sizeof(DWORD);
            status = STATUS_SUCCESS;
        }
        break;
    default:
        status = STATUS_INVALID_DEVICE_REQUEST;
        break;
    }

    pIrp->IoStatus.Status = status;
    IoCompleteRequest(pIrp, IO_NO_INCREMENT);
    return status;
}

NTSTATUS DriverEntry(PDRIVER_OBJECT pDriverObject, PUNICODE_STRING pRegistryPath) {
    NTSTATUS status = STATUS_SUCCESS;

    UNICODE_STRING devName, symLinkName;
    RtlInitUnicodeString(&devName, DEVICE_NAME);
    RtlInitUnicodeString(&symLinkName, SYMBOLIC_NAME);

    status = IoCreateDevice(pDriverObject, 0, &devName, FILE_DEVICE_UNKNOWN, FILE_DEVICE_SECURE_OPEN, FALSE, &g_pDeviceObject);
    if (!NT_SUCCESS(status)) {
        return status;
    }

    status = IoCreateSymbolicLink(&symLinkName, &devName);
    if (!NT_SUCCESS(status)) {
        IoDeleteDevice(g_pDeviceObject);
        return status;
    }

    pDriverObject->MajorFunction[IRP_MJ_CREATE] = HelloWorldDispatchRoutine;
    pDriverObject->MajorFunction[IRP_MJ_CLOSE] = HelloWorldDispatchRoutine;
    pDriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = HelloWorldDispatchRoutine;

    return status;
}

VOID DriverUnload(PDRIVER_OBJECT pDriverObject) {
    UNICODE_STRING symLinkName;
    RtlInitUnicodeString(&symLinkName, SYMBOLIC_NAME);

    IoDeleteSymbolicLink(&symLinkName);
    IoDeleteDevice(g_pDeviceObject);
}

4. 在DriverTestDriver.cpp中，添加以下代码，在DriverEntry函数中注册DriverUnload回调函数：

pDriverObject->DriverUnload = DriverUnload;

5. 运行程序，在控制台输出中可以看到从驱动程序中获取到的数据。

上面的示例代码实现了一个简单的驱动程序，该驱动程序创建了一个设备对象和一个符号链接，并注册了设备对象的三个回调函数（Create、Close、DeviceControl）。在应用程序中，通过CreateFile打开设备对象，通过DeviceIoControl发送IOCTL请求，从驱动程序中获取数据并打印出来。