Windows NT Driver >> Assembly >> File

DO_NEITHER_IO


參考資訊:
1. Four-F
2. Source Code

基本上,Microsoft沒有定義DO_NEITHER_IO這個Flag,而Neither I/O的意思就是Neither Buffered Nor Direct I/O,因此,當沒有設定DO_BUFFERED_IO或DO_DIRECT_IO Flag時,就會使用Neither的方式,使用這種方式時,I/O Manager會將User Buffer的指標,透過操作後,傳遞給驅動程式使用,因此,驅動程式可以直接存取User Buffer的資料,所以存取速度可以得到很大的改善,對於有速度要求的驅動程式來說,建議使用Neither的方式,不過,關於User Buffer指標的存取問題上,會遇到更多需要面對的問題,如:指標的有效性以及多次存取的同步問題,因此,在選擇使用上,更需要考量到這些額外付出的代價是否值得使用,因為,驅動程式以及User Application雙方都需要很嚴謹的看待這塊共用的Buffer。

Microsoft的說明網頁:
using-neither-buffered-nor-direct-i-o

記憶體指標:

IRP Buffer Length
IRP_MJ_READ (Irp)
UserBuffer
(IrpStack)
Parameters.Read.Length
IRP_MJ_WRITE (Irp)
UserBuffer
(IrpStack)
Parameters.Write.Length

main.asm

.386p
.model flat, stdcall
option casemap:none

include c:\masm32\Macros\Strings.mac
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\include\wxp\wdm.inc
include c:\masm32\include\wxp\seh0.inc
includelib c:\masm32\lib\wxp\i386\ntoskrnl.lib
 
public DriverEntry
 
OurDeviceExtension struct
  pNextDevice PDEVICE_OBJECT ?
  szBuffer byte 255 dup(?)
OurDeviceExtension ends

.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

.code
IrpOpenClose proc pOurDevice: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

IrpReadWrite proc uses ebx pOurDevice:PDEVICE_OBJECT, pIrp:PIRP
  local bReadable:dword
  local bWritable:dword
  local dwLen:dword
  local pBuf:dword
  local pdx:PTR OurDeviceExtension
  
  and dwLen, 0
  mov eax, pOurDevice
  push (DEVICE_OBJECT PTR [eax]).DeviceExtension
  pop pdx
  
  IoGetCurrentIrpStackLocation pIrp
  movzx eax, (IO_STACK_LOCATION PTR [eax]).MajorFunction
  .if eax == IRP_MJ_WRITE
    invoke DbgPrint, $CTA0("IRP_MJ_WRITE")
    
    IoGetCurrentIrpStackLocation pIrp
    push (IO_STACK_LOCATION PTR [eax]).Parameters.Write._Length
    pop dwLen
   
    mov eax, pIrp
    push (_IRP PTR [eax]).UserBuffer
    pop pBuf
    invoke DbgPrint, $CTA0("Address: 0x%x, Length: %d"), pBuf, dwLen
    
    mov bReadable, 0
    _try
      invoke ProbeForRead, pBuf, dwLen, 1
      mov eax, pdx
      mov ebx, pBuf
      invoke memcpy, addr (OurDeviceExtension PTR [eax]).szBuffer, ebx, dwLen
      mov bReadable, 1
    _finally
      .if bReadable == 0
        invoke DbgPrint, $CTA0("Failed to read from user buffer")
      .endif
  .elseif eax == IRP_MJ_READ
    invoke DbgPrint, $CTA0("IRP_MJ_READ")
   
    mov eax, pIrp
    push (_IRP PTR [eax]).UserBuffer
    pop pBuf

    mov bWritable, 0
    _try
      invoke ProbeForWrite, pBuf, dwLen, 1
      mov eax, pOurDevice
      push (DEVICE_OBJECT PTR [eax]).DeviceExtension
      pop pdx
    
      mov eax, pdx
      mov ebx, pBuf
      invoke strcpy, ebx, addr (OurDeviceExtension PTR [eax]).szBuffer
      
      mov eax, pdx
      invoke strlen, addr (OurDeviceExtension PTR [eax]).szBuffer
      inc eax
      push eax
      pop dwLen
    
      mov bWritable, 1
    _finally
      .if bWritable == 0
        invoke DbgPrint, $CTA0("Failed to write to user buffer")
      .endif
  .endif
  
  mov eax, pIrp
  push dwLen
  pop (_IRP PTR [eax]).IoStatus.Information
  mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS
  fastcall IofCompleteRequest, pIrp, IO_NO_INCREMENT
  mov eax, STATUS_SUCCESS
  ret
IrpReadWrite 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_WRITE  * (sizeof PVOID)], offset IrpReadWrite
  mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_READ   * (sizeof PVOID)], offset IrpReadWrite
  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
    and (DEVICE_OBJECT PTR [eax]).Flags, not DO_DEVICE_INITIALIZING
    invoke IoCreateSymbolicLink, addr szSymName, addr suDevName
  .endif
  ret
DriverEntry endp
end DriverEntry
.end

IrpFile()收到IRP_MJ_WRITE時,Driver複製User Buffer的內容到szBuffer,而收到IRP_MJ_READ時,將szBuffer內容又複製回User Buffer,完成暫存的功能,IoStatus.Information的數值就是ReadFile()或WriteFile()完成的長度。

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

includelib c:\masm32\lib\user32.lib
includelib c:\masm32\lib\masm32.lib
includelib c:\masm32\lib\msvcrt.lib
includelib c:\masm32\lib\kernel32.lib

.const
DEV_NAME db "\\.\MyDriver",0
MSG_ERR  db "failed to open mydriver",0
MSG_SEND db "I am error",0
MSG_WR   db "WR: %s, %d",10,13,0
MSG_RD   db "RD: %s, %d",10,13,0

.data?
hFile    dd ?
dwRet    dd ?
szBuffer db 255 dup(?)

.code
start:
  invoke CreateFile, offset DEV_NAME, GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0
  .if eax == INVALID_HANDLE_VALUE
    invoke crt_printf, offset MSG_ERR
    invoke ExitProcess, -1
  .endif
  
  mov hFile, eax
  invoke StrLen, offset MSG_SEND
  inc eax
  mov dwRet, eax
  invoke crt_printf, offset MSG_WR, offset MSG_SEND, dwRet
  invoke WriteFile, hFile, offset MSG_SEND, dwRet, offset dwRet, 0
  invoke crt_memset, offset szBuffer, 0, 255
  invoke ReadFile, hFile, offset szBuffer, 255, offset dwRet, 0
  invoke crt_printf, offset MSG_RD, offset szBuffer, dwRet
  invoke CloseHandle, hFile
  invoke ExitProcess, 0

end start

結果


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