Windows NT Driver >> C/C++
Cancel IRP
參考資訊:
1. Source Code
2. canceling-irps
有處理Irp就會有Cancel Irp的時候,Cancel Irp本身就是一個很複雜的課題,司徒在這一篇教學不會做深入探討,有興趣的使用者可以參考上面的參考資訊,取而代之的,司徒只是點出,在處理Irp時,使用者要意識到該Irp可能已經被Cancel掉了,作法上,也是可以切割成很多時期,如:Irp處理前,Irp處裡中,Irp處裡後,因此,在設計驅動程式時,對於Cancel機制有必要嚴謹看待,因為,BSOD常常就是這樣發生了,不過司徒在此僅針對Irp處裡前,作簡單判斷,是否User Application已經Cancel這個Irp,如果沒有被Cancel,則Complete Irp,相反地,如果被Cancel,則Cancel Irp,Cancel作法如下:
1. CancelRoutine(NULL)
2. IoCompleteRequest(STATUS_CANCELLED)
main.c
#include <wdm.h> #define IOCTL_QUEUE CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_ANY_ACCESS) #define IOCTL_PROCESS CTL_CODE(FILE_DEVICE_UNKNOWN, 0x801, METHOD_BUFFERED, FILE_ANY_ACCESS) #define DEV_NAME L"\\Device\\MyDriver" #define SYM_NAME L"\\DosDevices\\MyDriver" KDPC stDPC={0}; KTIMER stTime={0}; LIST_ENTRY stQueue={0}; VOID OnTimer(struct _KDPC *Dpc, PVOID DeferredContext, PVOID SystemArgument1, PVOID SystemArgument2) { PIRP pIrp; PLIST_ENTRY plist; if(IsListEmpty(&stQueue) == TRUE){ KeCancelTimer(&stTime); DbgPrint("Finish"); } else{ plist = RemoveHeadList(&stQueue); pIrp = CONTAINING_RECORD(plist, IRP, Tail.Overlay.ListEntry); if(pIrp->Cancel != TRUE){ pIrp->IoStatus.Status = STATUS_SUCCESS; pIrp->IoStatus.Information = 0; IoCompleteRequest(pIrp, IO_NO_INCREMENT); DbgPrint("Complete Irp"); } else{ pIrp->CancelRoutine = NULL; pIrp->IoStatus.Status = STATUS_CANCELLED; pIrp->IoStatus.Information = 0; IoCompleteRequest(pIrp, IO_NO_INCREMENT); DbgPrint("Cancel Irp"); } } } void Unload(PDRIVER_OBJECT pOurDriver) { UNICODE_STRING usSymboName; RtlInitUnicodeString(&usSymboName, L"\\DosDevices\\MyDriver"); IoDeleteSymbolicLink(&usSymboName); IoDeleteDevice(pOurDriver->DeviceObject); } NTSTATUS IrpIOCTL(PDEVICE_OBJECT pOurDevice, PIRP pIrp) { LARGE_INTEGER stTimePeriod; PIO_STACK_LOCATION psk = IoGetCurrentIrpStackLocation(pIrp); switch(psk->Parameters.DeviceIoControl.IoControlCode){ case IOCTL_QUEUE: DbgPrint("IOCTL_QUEUE"); InsertHeadList(&stQueue, &pIrp->Tail.Overlay.ListEntry); IoMarkIrpPending(pIrp); return STATUS_PENDING; case IOCTL_PROCESS: DbgPrint("IOCTL_PROCESS"); stTimePeriod.HighPart|= -1; stTimePeriod.LowPart = -10000000; KeSetTimerEx(&stTime, stTimePeriod, 1000, &stDPC); break; } pIrp->IoStatus.Information = 0; pIrp->IoStatus.Status = STATUS_SUCCESS; IoCompleteRequest(pIrp, IO_NO_INCREMENT); return STATUS_SUCCESS; } NTSTATUS IrpFile(PDEVICE_OBJECT pOurDevice, PIRP pIrp) { PIO_STACK_LOCATION psk = IoGetCurrentIrpStackLocation(pIrp); switch(psk->MajorFunction){ case IRP_MJ_CREATE: DbgPrint("IRP_MJ_CREATE"); break; case IRP_MJ_CLOSE: DbgPrint("IRP_MJ_CLOSE"); break; } IoCompleteRequest(pIrp, IO_NO_INCREMENT); return STATUS_SUCCESS; } NTSTATUS DriverEntry(PDRIVER_OBJECT pOurDriver, PUNICODE_STRING pOurRegistry) { PDEVICE_OBJECT pOurDevice=NULL; UNICODE_STRING usDeviceName; UNICODE_STRING usSymboName; pOurDriver->MajorFunction[IRP_MJ_CREATE] = pOurDriver->MajorFunction[IRP_MJ_CLOSE] = IrpFile; pOurDriver->MajorFunction[IRP_MJ_DEVICE_CONTROL] = IrpIOCTL; pOurDriver->DriverUnload = Unload; RtlInitUnicodeString(&usDeviceName, L"\\Device\\MyDriver"); IoCreateDevice(pOurDriver, 0, &usDeviceName, FILE_DEVICE_UNKNOWN, 0, FALSE, &pOurDevice); RtlInitUnicodeString(&usSymboName, L"\\DosDevices\\MyDriver"); InitializeListHead(&stQueue); KeInitializeTimer(&stTime); KeInitializeDpc(&stDPC, OnTimer, pOurDevice); IoCreateSymbolicLink(&usSymboName, &usDeviceName); pOurDevice->Flags&= ~DO_DEVICE_INITIALIZING; pOurDevice->Flags|= DO_BUFFERED_IO; return STATUS_SUCCESS; }
DriverEntry()初始List以及DPC Timer,DPC Timer用來定期確認List是否還有資料需要處理,當然,使用Thread檢查或許更恰當些
IrpIOCTL()IOCTL_QUEUE代表該IOCTL會被Queue起來,稍後處理,而當收到IOCTL_PROCESS時,則啟動DPC Timer開始處理那些被Queue起來的Irp
OnTimer()處理Queue裡面的Irp,在處理前,先判斷該Irp是否已經被Cancel了
app.c
#define INITGUID #include <windows.h> #include <winioctl.h> #include <strsafe.h> #include <setupapi.h> #include <stdio.h> #include <stdlib.h> #define IOCTL_QUEUE CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_ANY_ACCESS) #define IOCTL_PROCESS CTL_CODE(FILE_DEVICE_UNKNOWN, 0x801, METHOD_BUFFERED, FILE_ANY_ACCESS) int __cdecl main(int argc, char* argv[]) { int i=0; DWORD dwRet = 0; HANDLE hFile = NULL; OVERLAPPED ov[3]={0}; hFile = CreateFile("\\\\.\\MyDriver", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED | FILE_ATTRIBUTE_NORMAL, NULL); if (hFile == INVALID_HANDLE_VALUE) { printf("failed to open mydriver\n"); return -1; } for(i=0; i<3; i++){ memset(&ov[i], 0, sizeof(ov[i])); ov[i].hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); printf("queue event\n"); DeviceIoControl(hFile, IOCTL_QUEUE, NULL, 0, NULL, 0, &dwRet, &ov[i]); } printf("process all of events\n"); DeviceIoControl(hFile, IOCTL_PROCESS, NULL, 0, NULL, 0, &dwRet, NULL); Sleep(1000); CancelIo(hFile); for(i=0; i<3; i++){ WaitForSingleObject(ov[i].hEvent, INFINITE); CloseHandle(ov[i].hEvent); printf("wait complete\n"); } CloseHandle(hFile); return 0; }
結果