Windows Driver Model >> Assembly >> Synchronization
Mutex
參考資訊:
1. Source Code
Mutex是一個互斥的機制,有點類似Spin Lock,當有CPU取得Mutex後,其餘CPU會處於Wait狀態,而相較於Spin Lock,Mutex並不會讓CPU處於忙碌的狀態,也不會提升到DISPATCH_LEVEL,是一個相當適合用來做序列化的機制,使用步驟如下:
1. KeInitializeMutex()
2. KeWaitForSingleObject()
3. KeReleaseMutex()
main.asm
.386p .model flat, stdcall option casemap:none include c:\masm32\include\w2k\hal.inc include c:\masm32\include\w2k\ntstatus.inc include c:\masm32\include\w2k\ntddk.inc include c:\masm32\include\w2k\ntoskrnl.inc include c:\masm32\include\w2k\ntddkbd.inc include c:\masm32\Macros\Strings.mac includelib c:\masm32\lib\wxp\i386\hal.lib includelib c:\masm32\lib\wxp\i386\ntoskrnl.lib public DriverEntry MAX_THREAD equ 3 .data myMutex KMUTEX <> pNextDev PDEVICE_OBJECT 0 .const DEV_NAME word "\","D","e","v","i","c","e","\","M","y","D","r","i","v","e","r",0 SYM_NAME word "\","D","o","s","D","e","v","i","c","e","s","\","M","y","D","r","i","v","e","r",0 MSG_ACQUIRING byte "Thread%d, Acquiring Mutex",0 MSG_ACQUIRED byte "Thread%d, Acquired Mutex",0 MSG_SLEEPING byte "Thread%d, Sleeping", 0 MSG_RELEASING byte "Thread%d, Releasing Mutex",0 MSG_RELEASED byte "Thread%d, Released Mutex",0 .code MyThread proc pParam:DWORD local stTime:LARGE_INTEGER or stTime.HighPart, -1 mov stTime.LowPart, -10000000 invoke DbgPrint, offset MSG_ACQUIRING, pParam invoke KeWaitForSingleObject, offset myMutex, Executive, KernelMode, FALSE, NULL invoke DbgPrint, offset MSG_ACQUIRED, pParam invoke DbgPrint, offset MSG_SLEEPING, pParam invoke KeDelayExecutionThread, KernelMode, FALSE, addr stTime invoke DbgPrint, offset MSG_RELEASING, pParam invoke KeReleaseMutex, offset myMutex, FALSE invoke DbgPrint, offset MSG_RELEASED, pParam invoke PsTerminateSystemThread, STATUS_SUCCESS ret MyThread endp IrpPnp proc pDevObj:PDEVICE_OBJECT, pIrp:PIRP local pdx:PTR OurDeviceExtension local szSymName:UNICODE_STRING mov eax, pDevObj push (DEVICE_OBJECT PTR [eax]).DeviceExtension pop pdx IoGetCurrentIrpStackLocation pIrp movzx eax, (IO_STACK_LOCATION PTR [eax]).MinorFunction .if eax == IRP_MN_START_DEVICE mov eax, pIrp mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS .elseif eax == IRP_MN_REMOVE_DEVICE invoke RtlInitUnicodeString, addr szSymName, offset SYM_NAME invoke IoDeleteSymbolicLink, addr szSymName mov eax, pIrp mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS mov eax, pdx invoke IoDetachDevice, pNextDev invoke IoDeleteDevice, pDevObj .endif IoSkipCurrentIrpStackLocation pIrp mov eax, pdx invoke IoCallDriver, pNextDev, pIrp ret IrpPnp endp AddDevice proc pOurDriver:PDRIVER_OBJECT, pPhyDevice:PDEVICE_OBJECT local pOurDevice:PDEVICE_OBJECT local suDevName:UNICODE_STRING local szSymName:UNICODE_STRING invoke RtlInitUnicodeString, addr suDevName, offset DEV_NAME invoke RtlInitUnicodeString, addr szSymName, offset SYM_NAME invoke IoCreateDevice, pOurDriver, 0, addr suDevName, FILE_DEVICE_UNKNOWN, 0, FALSE, addr pOurDevice .if eax == STATUS_SUCCESS invoke IoAttachDeviceToDeviceStack, pOurDevice, pPhyDevice .if eax != NULL push eax pop pNextDev mov eax, pOurDevice or (DEVICE_OBJECT PTR [eax]).Flags, DO_BUFFERED_IO and (DEVICE_OBJECT PTR [eax]).Flags, not DO_DEVICE_INITIALIZING invoke IoCreateSymbolicLink, addr szSymName, addr suDevName .endif .endif ret AddDevice endp Unload proc pOurDriver:PDRIVER_OBJECT ret Unload endp DriverEntry proc pOurDriver:PDRIVER_OBJECT, pOurRegistry:PUNICODE_STRING local hThread:DWORD local cnt:DWORD mov eax, pOurDriver mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_PNP * (sizeof PVOID)], offset IrpPnp mov (DRIVER_OBJECT PTR [eax]).DriverUnload, offset Unload mov eax, (DRIVER_OBJECT PTR [eax]).DriverExtension mov (DRIVER_EXTENSION PTR [eax]).AddDevice, AddDevice invoke KeInitializeMutex, offset myMutex, 0 mov cnt, 0 th: invoke PsCreateSystemThread, addr hThread, THREAD_ALL_ACCESS, NULL, -1, NULL, offset MyThread, cnt .if eax == STATUS_SUCCESS invoke ZwClose, hThread .endif inc cnt cmp cnt, MAX_THREAD jnz th mov eax, STATUS_SUCCESS ret DriverEntry endp end DriverEntry .end
DriverEntry()產生3個Thread,每個Thread會嘗試取得Mutex,一旦取得Mutex後,會延遲一秒後才釋放Mutex,達到一次只能有一個CPU執行的效果
結果