应用方面的编程(5)

打开设备

//C中符号链接里面的""需要转义使用"\"转义
#define CWK_DEV_SYM L"\\.\slbkcdo_3948d33e"
//表示设备的路径
//打开设备
int _tmain(int argc, _TCHAR* argv[])
{
HANDLE device =NULL;
......
//操作驱动,先打开设备
device=CreateFile(CWK_DEV_SYM,GENERIC_READ|GENERIC_WRITE,0,0,OPEN_EXISTING,FILE_ATTRIBUTE_SYSTEM,0);
if (device == INVALID_HANDLE_VALUE)
{
printf("coworker demo:Open device failed.rn");
return -1;
}
else
printf("coworker demo:Open device successfully.rn");
}

关闭设备

CloseHandle(device);

//从应用层给设备发送一个字符串
#define CWK_DEV_SEND_STR 

(ULOCK)CTL_CODE( 

FILE_DEVICE_UNKNOWN, 

0x911,METHOD_BUFFERED, 

FIEL_WRITE_DATA
)
//从内核接收字符串
#define CWK_DEV_RECV_STR 
(ULONG)CTL_CODE(

FILE_DEVICE_UNKNOWN, 
0x912,METHOD_BUFFERED, 
FILE_READ_DATA
)

发送请求的过程

int _tmain(int argc, _TCHAR* arv[])
{
...
char *msg = {"Hellodriver,this is a message from application.rn"};
...
if(!DeviceIoControl(device,CWK_DEV_SEND_STR,msg,strlen(msg)+1,NULL,0,&ret_len,0))
{
printf("coworker demo:send message failed.rn");
ret = -2;
}
else
prrintf("coworker demo :send message successfully.rn");
.....
}

内核中对应用控制请求的处理(获得功号,缓冲区)

if(irpsp->MajorFunction == IRP_MJ_DEVICE_CONTROL)
{
//获得缓冲区
PVOID buffer = irp->AssociatedIrp.SystemBuffer;
//获取缓冲区长度
ULONG inline = irpsp->Parameters.DeviceIoControl.InputBufferLength;
//获取输出缓冲区的长度
ULONG OUTLEN = irpsp->Parameters.DeviceIoControl.OutputBufferLength;
....
}
完整的分发函数
NTSTATUS cwkDispatch(
IN PDEVICE_OBJECT dev,IN PIRP irp)
{
PIO_STACK_LOCATION irpsp = IoGetCurrentIrpStackLocation(irp);
NTSTATUS status = STATUS_SUCCESS;
ULONG ret_len = 0;
while(dev == g_cdo)//这个驱动只生成了这一个设备,如果不是发给他的返回失败就可以了
{
if(irpsp->MjorFunction ==IRP_MJ_CREATE || IRP->MajorFunction ==IRP_MJ_CLOSE)
{//生成和关闭请求,直接返回成功,表示随时可以打开关闭
break;
}
if(irpsp->MajorFunction == IRP_MJ_DEVICE_CONTROL)
{
//处理DeviceControl
PVOID buffer = irp->AssociatedIrp.SystemBuffer;
ULNOG inline = irpsp->Parameters.DeviceIoControl.InputBufferLength;
ULONG outlen = irpsp->Parameters.DeviceIoControl.OutputBufferLength;

swich(irpsp->Parameters.DeviceIoControl.IoControlCode)
{
case CWK_DEV_SEND_STR;
ASSERT(buffer != NULL);
ASSERT(inline >0);
ASSERT(outline ==0);
DbgPrint((char *)buffer);
//打印完,认为请求成功
break;
case CWK_DEV_RECV_STR;
default;
//到这的请求都是不接受的,未知一律视为非法
//参数错误
status = STATUS_INVALID_PARAMETER;
break;
}
}
break;
}
//到这的请求都是不接受的,未知一律视为非法
irp->IoStatus.Information = ret_len;
irp->IoStatus.Status = status;
IoCompleteRequest(irp,IO_NO_INCREMENT);
return status;

}

最后

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