0.driverbase—IOCtl的三种数据交互方式(buffer、direct、other)

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#define IOCTL_DIRECT_IN_IOCTL_CODE(FILE_DEVICE_COMM_DRIVER, 0x700, METHOD_IN_DIRECT,  FILE_READ_ACCESS¦FILE_WRITE_ACCESS)//直接输入缓冲输出I/O#define IOCTL_DIRECT_OUT_IO   CTL_CODE(FILE_DEVICE_COMM_DRIVER, 0x701, METHOD_OUT_DIRECT, FILE_READ_ACCESS¦FILE_WRITE_ACCESS)//缓冲输入直接输出I/O#define IOCTL_BUFFERED_IO CTL_CODE(FILE_DEVICE_COMM_DRIVER, 0x702, METHOD_BUFFERED,   FILE_READ_ACCESS¦FILE_WRITE_ACCESS)//输入输出缓冲I/O#define IOCTL_NEITHER_IO  CTL_CODE(FILE_DEVICE_COMM_DRIVER, 0x703, METHOD_NEITHER,FILE_READ_ACCESS¦FILE_WRITE_ACCESS)//Other I/0

IOCTL请求有以上四种

它们的输入输出缓冲区方式如下：

IOCTL请求类型输入缓冲存地址输出缓冲区地址METHOD_IN_DIRECT/ METHOD_OUT_DIRECTIrp->AssociatedIrp.SystemBufferMmGetSystemAddressForMdlSafe(Irp->MdlAddress, NormalPagePriority)METHOD_BUFFEREDIrp->AssociatedIrp.SystemBufferIrp->AssociatedIrp.SystemBufferMETHOD_NEITHERpIoStackIrp->Parameters.DeviceIoControl.Type3InputBufferpIoStackIrp->Parameters.DeviceIoContMETHOD_IN_DIRECT/ METHOD_OUT_DIRECT 示例代码：

NTSTATUS DirectIo(PIRP Irp, PIO_STACK_LOCATION pIoStackIrp){//以下四个变量都由DeviceIoControl参数传入ULONG ulInputLength = pIoStackIrp->Parameters.DeviceIoControl.InputBufferLength;//输入长度PVOID pInputBuf = Irp->AssociatedIrp.SystemBuffer;//输入buf ULONG ulOutputLength = pIoStackIrp->Parameters.DeviceIoControl.OutputBufferLength;//输出长度PVOID pOutputBuf = NULL;if (Irp->MdlAddress){pOutputBuf = MmGetSystemAddressForMdlSafe(Irp->MdlAddress, NormalPagePriority);} //TODO.对pOutputBuf 赋值}

METHOD_BUFFERED 示例代码：

NTSTATUS BufferIo(PIRP Irp, PIO_STACK_LOCATION pIoStackIrp){//以下四个变量都由DeviceIoControl参数传入ULONG ulInputLength = pIoStackIrp->Parameters.DeviceIoControl.InputBufferLength;//输入长度PVOID pInputBuf = Irp->AssociatedIrp.SystemBuffer;//输入buf ULONG ulOutputLength = pIoStackIrp->Parameters.DeviceIoControl.OutputBufferLength;//输出长度PVOID pOutputBuf = Irp->AssociatedIrp.SystemBuffer; //TODO.对pOutputBuf 赋值}

我们注意到BufferIo中输入和输出指向同一个缓冲区，如果输入数据有用的话，我们应当从系统缓冲区（ Irp->AssociatedIrp.SystemBuffer）先获取输入，再将输出写入到系统缓冲区（同一个地方： Irp->AssociatedIrp.SystemBuffer）。当完成请求时，I/O 系统将输出数据从系统缓冲区复制到用户缓冲区

METHOD_NEITHER示例：

NTSTATUS NeitherIo(PIRP Irp, PIO_STACK_LOCATION pIoStackIrp){//以下四个变量都由DeviceIoControl参数传入ULONG ulInputLength = pIoStackIrp->Parameters.DeviceIoControl.InputBufferLength;//输入长度PVOID pInputBuf = pIoStackIrp->Parameters.DeviceIoControl.Type3InputBuffer;//输入buf ULONG ulOutputLength = pIoStackIrp->Parameters.DeviceIoControl.OutputBufferLength;//输出长度PVOID pOutputBuf = Irp->UserBuffer; //TODO.对pOutputBuf 赋值}

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