Windows NT Driver >> Assembly
Queue IRP
參考資訊：
1. Four-F
2. Source Code
驅動程式作為User Application跟硬體的溝通橋樑，最常遇到的問題就是硬體處理速度不夠快，導致驅動程式需要等待硬體完成後，再繼續處理下一筆資料，但是驅動程式如果要跟User Application溝通這些同步事情，會產生額外的等待時間，因此，為了達到比較好的處理效能，一般驅動程式做會Queue Irp的動作，讓處理的間隔可以縮到最小，這也是這篇教學要說明的東西，教導使用者一些Queue Irp的基本觀念和作法。
首先要知道的就是，儲存Irp的地方在哪？在Windows驅動程式裡，可以使用List作為儲存媒介(使用者也可以使用其它方式儲存)，使用步驟相當簡單，如下所示：
1. InitializeListHead()
2. InsertHeadList()
3. IsListEmpty()
4. RemoveHeadList()
首先初始化List(InitializeListHead())，接著插入(InsertHeadList())需要儲存的資料，接著判斷List是否還有資料(IsListEmpty())，假如還有資料，則取出(RemoveHeadList())處裡
Irp是處裡資料的最小單位，一個Irp通常代表處理一筆資料的訊息，因此，當硬體來不及處理資料時，驅動程式需要做Pending Irp的動作，讓User Application知道這筆資料稍後處理，Pending Irp的步驟如下：
1. IoMarkIrpPending()
2. IoCompleteRequest(STATUS_PENDING)
回傳Pending，告知I/O Manager，這筆Irp資料先Pending一下，稍後處理
接著就是User Application如何知道資料是否處理完畢或者被Pending了呢？在CreateFile()時，如果沒有用FILE_FLAG_OVERLAPPED，則代表每一筆資料都是必須完成才會回傳，此種寫法也稱為Blocking方式，如：呼叫WriteFile()後，必須等待驅動程式完成該Irp才會繼續往下，否則呼叫WriteFile()後，會卡在這個Win32 API，相反地，如果CreateFile()使用FILE_FLAG_OVERLAPPED，而呼叫WriteFile()時，驅動程式回傳Pending，則WriteFile()會馬上回傳ERROR_IO_PENDING，告知User Application，該筆資料驅動程式會稍後處裡，此種寫法也稱為Non-Blocking方式，那如何得知該筆資料處理完畢了呢？當使用Non-Blocking寫法，會在WriteFile()傳入一個OVERLAPPED參數，該參數裡面有一個Event，用來告知是否已經處理完畢了。
Queue IRP流程:
1. InsertHeadList()
2. IoMarkIrpPending()
3. IoCompleteRequest(STATUS_PENDING)
4. IsListEmpty()
5. RemoveHeadList()
6. IoCompleteRequest(STATUS_SUCCESS)
main.asm
.386p
.model flat, stdcall
option casemap:none
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\ntoskrnl.lib
public DriverEntry
OurDeviceExtension struct
pNextDev PDEVICE_OBJECT ?
stQueue LIST_ENTRY <>
stDPC KDPC <>
stTime KTIMER <>
OurDeviceExtension ends
IOCTL_QUEUE equ CTL_CODE(FILE_DEVICE_UNKNOWN, 800h, METHOD_BUFFERED, FILE_ANY_ACCESS)
IOCTL_PROCESS equ CTL_CODE(FILE_DEVICE_UNKNOWN, 801h, METHOD_BUFFERED, FILE_ANY_ACCESS)
.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_QUEUE byte "IOCTL_QUEUE",0
MSG_PROCESS byte "IOCTL_PROCESS",0
.code
OnTimer proc pDpc:PKDPC, pContext:PVOID, pArg1:PVOID, PArg2:PVOID
mov eax, pContext
mov eax, (DEVICE_OBJECT PTR [eax]).DeviceExtension
lea eax, (OurDeviceExtension PTR [eax]).stQueue
IsListEmpty eax
.if eax == TRUE
mov eax, pContext
mov eax, (DEVICE_OBJECT PTR [eax]).DeviceExtension
invoke KeCancelTimer, addr (OurDeviceExtension PTR [eax]).stTime
invoke DbgPrint, $CTA0("Finish")
.else
mov eax, pContext
mov eax, (DEVICE_OBJECT PTR [eax]).DeviceExtension
lea eax, (OurDeviceExtension PTR [eax]).stQueue
RemoveHeadList eax
; CONTAINING_RECORD
sub eax, _IRP.Tail.Overlay.ListEntry
mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS
push 0
pop (_IRP PTR [eax]).IoStatus.Information
fastcall IofCompleteRequest, eax, IO_NO_INCREMENT
invoke DbgPrint, $CTA0("Complete Irp")
.endif
ret
OnTimer endp
IrpOpenClose proc pDevObj:PDEVICE_OBJECT, pIrp:PIRP
IoGetCurrentIrpStackLocation pIrp
movzx eax, (IO_STACK_LOCATION PTR [eax]).MajorFunction
.if eax == IRP_MJ_CREATE
invoke DbgPrint, $CTA0("IRP_MJ_CREATE")
.elseif eax == IRP_MJ_CLOSE
invoke DbgPrint, $CTA0("IRP_MJ_CLOSE")
.endif
mov eax, pIrp
and (_IRP PTR [eax]).IoStatus.Information, 0
mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS
fastcall IofCompleteRequest, pIrp, IO_NO_INCREMENT
mov eax, STATUS_SUCCESS
ret
IrpOpenClose endp
IrpIOCTL proc uses ebx ecx pOurDevice:PDEVICE_OBJECT, pIrp:PIRP
local pdx:PTR Dev_Ext
local stTimePeriod:LARGE_INTEGER
mov eax, pOurDevice
push (DEVICE_OBJECT PTR [eax]).DeviceExtension
pop pdx
IoGetCurrentIrpStackLocation pIrp
mov eax, (IO_STACK_LOCATION PTR [eax]).Parameters.DeviceIoControl.IoControlCode
.if eax == IOCTL_QUEUE
invoke DbgPrint, offset MSG_QUEUE
mov ebx, pdx
lea ebx, (OurDeviceExtension PTR [ebx]).stQueue
mov ecx, pIrp
lea ecx, (_IRP PTR [ecx]).Tail.Overlay.ListEntry
InsertHeadList ebx, ecx
IoMarkIrpPending pIrp
mov eax, STATUS_PENDING
ret
.elseif eax == IOCTL_PROCESS
invoke DbgPrint, offset MSG_PROCESS
or stTimePeriod.HighPart, -1
mov stTimePeriod.LowPart, -10000000
mov ebx, pdx
invoke KeSetTimerEx, addr (OurDeviceExtension PTR [ebx]).stTime, stTimePeriod.LowPart, stTimePeriod.HighPart, 10, addr (OurDeviceExtension PTR [ebx]).stDPC
.endif
mov eax, pIrp
mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS
and (_IRP PTR [eax]).IoStatus.Information, 0
fastcall IofCompleteRequest, pIrp, IO_NO_INCREMENT
mov eax, STATUS_SUCCESS
ret
IrpIOCTL endp
Unload proc pOurDriver:PDRIVER_OBJECT
local szSymName:UNICODE_STRING
invoke RtlInitUnicodeString, addr szSymName, offset SYM_NAME
invoke IoDeleteSymbolicLink, addr szSymName
mov eax, pOurDriver
invoke IoDeleteDevice, (DRIVER_OBJECT PTR [eax]).DeviceObject
ret
Unload endp
DriverEntry proc pOurDriver:PDRIVER_OBJECT, pOurRegistry:PUNICODE_STRING
local pOurDevice:PDEVICE_OBJECT
local suDevName:UNICODE_STRING
local szSymName:UNICODE_STRING
mov eax, pOurDriver
mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_CREATE * (sizeof PVOID)], offset IrpOpenClose
mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_CLOSE * (sizeof PVOID)], offset IrpOpenClose
mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_DEVICE_CONTROL * (sizeof PVOID)], offset IrpIOCTL
mov (DRIVER_OBJECT PTR [eax]).DriverUnload, offset Unload
invoke RtlInitUnicodeString, addr suDevName, offset DEV_NAME
invoke RtlInitUnicodeString, addr szSymName, offset SYM_NAME
invoke IoCreateDevice, pOurDriver, sizeof OurDeviceExtension, addr suDevName, FILE_DEVICE_UNKNOWN, 0, FALSE, addr pOurDevice
.if eax == STATUS_SUCCESS
mov eax, pOurDevice
or (DEVICE_OBJECT PTR [eax]).Flags, DO_BUFFERED_IO
and (DEVICE_OBJECT PTR [eax]).Flags, not DO_DEVICE_INITIALIZING
mov eax, pOurDevice
mov eax, (DEVICE_OBJECT PTR [eax]).DeviceExtension
lea eax, (OurDeviceExtension PTR [eax]).stQueue
InitializeListHead eax
mov eax, pOurDevice
mov eax, (DEVICE_OBJECT PTR [eax]).DeviceExtension
invoke KeInitializeTimer, addr (OurDeviceExtension ptr [eax]).stTime
mov eax, pOurDevice
mov eax, (DEVICE_OBJECT PTR [eax]).DeviceExtension
invoke KeInitializeDpc, addr (OurDeviceExtension ptr [eax]).stDPC, offset OnTimer, pOurDevice
invoke IoCreateSymbolicLink, addr szSymName, addr suDevName
.endif
ret
DriverEntry endp
end DriverEntry
.end
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
app.asm
.386p
.model flat, stdcall
option casemap:none
include c:\masm32\include\windows.inc
include c:\masm32\include\masm32.inc
include c:\masm32\include\user32.inc
include c:\masm32\include\msvcrt.inc
include c:\masm32\include\kernel32.inc
include c:\masm32\include\w2k\ntddkbd.inc
include c:\masm32\Macros\Strings.mac
includelib c:\masm32\lib\user32.lib
includelib c:\masm32\lib\masm32.lib
includelib c:\masm32\lib\msvcrt.lib
includelib c:\masm32\lib\kernel32.lib
IOCTL_QUEUE equ CTL_CODE(FILE_DEVICE_UNKNOWN, 800h, METHOD_BUFFERED, FILE_ANY_ACCESS)
IOCTL_PROCESS equ CTL_CODE(FILE_DEVICE_UNKNOWN, 801h, METHOD_BUFFERED, FILE_ANY_ACCESS)
.const
DEV_NAME db "\\.\MyDriver",0
.data?
cnt dd ?
hFile dd ?
dwRet dd ?
event dd 3 dup(?)
ov OVERLAPPED <?>
.code
start:
invoke CreateFile, offset DEV_NAME, GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ, 0, OPEN_EXISTING, FILE_FLAG_OVERLAPPED or FILE_ATTRIBUTE_NORMAL, 0
.if eax == INVALID_HANDLE_VALUE
invoke crt_printf, $CTA0("failed to open mydriver\n")
invoke ExitProcess, -1
.endif
mov hFile, eax
invoke crt_memset, offset ov, 0, sizeof OVERLAPPED
mov cnt, 3
.while cnt > 0
invoke CreateEvent, NULL, TRUE, FALSE, NULL
push eax
pop ov.hEvent
mov ecx, cnt
mov edi, offset event
mov [edi + ecx * 4], eax
invoke crt_printf, $CTA0("queue event\n")
invoke DeviceIoControl, hFile, IOCTL_QUEUE, NULL, 0, NULL, 0, offset dwRet, offset ov
sub cnt, 1
.endw
invoke crt_printf, $CTA0("process all of events\n")
invoke DeviceIoControl, hFile, IOCTL_PROCESS, NULL, 0, NULL, 0, offset dwRet, NULL
mov cnt, 3
.while cnt > 0
mov ecx, cnt
mov edi, offset event
mov eax, [edi + ecx * 4]
push eax
pop ov.hEvent
invoke WaitForSingleObject, ov.hEvent, INFINITE
invoke CloseHandle, ov.hEvent
invoke crt_printf, $CTA0("wait complete\n")
sub cnt, 1
.endw
invoke CloseHandle, hFile
invoke ExitProcess, 0
end start
結果
