汇编DeviceIoControl接口详解

核心提示：在DIOCParams结构中有所有从Win32应用程序传送到你的VxD的信息，你的VxD至少要处理DIOC_Open(传送到dwIoControlCode),那是当Win32程序调用CreateFile打开你的VxD时VWIN32发送给你的VxD的，汇编DeviceIoControl接口详解(2)，如果你的VxD准备好

在DIOCParams结构中有所有从Win32应用程序传送到你的VxD的信息。

你的VxD至少要处理DIOC_Open(传送到dwIoControlCode),那是当Win32程序调用CreateFile打开你的VxD时VWIN32发送给你的VxD的。如果你的VxD准备好了，它必须在eax中返回0而且CreateFile也会成功。如果你的VxD没有准备好，它必须在eas中返回一个非零值而且CreateFile也会失败。除了DIOC_Open,当Win32程序关闭这个设备句柄时，你的VxD将会从VWIN32收到DIOC_Closehandle。

能由CreateFile加载的最小的动态VxD框架：

.386p
include vmm.inc
include vwin32.inc
DECLARE_VIRTUAL_DEVICE DYNAVXD,1,0, DYNAVXD_Control,\
UNDEFINED_DEVICE_ID, UNDEFINED_INIT_ORDER
Begin_control_dispatch DYNAVXD
Control_Dispatch w32_DeviceIoControl, OnDeviceIoControl
End_control_dispatch DYNAVXD
VxD_PAGEABLE_CODE_SEG
BeginProc OnDeviceIoControl
assume esi:ptr DIOCParams
.if [esi].dwIoControlCode==DIOC_Open
xor eax,eax
.endif
ret
EndProc OnDeviceIoControl
VxD_PAGEABLE_CODE_ENDS
end
;--------------------------------------------------------------------------------------------------------------------------------
; Module Definition File
;---------------------------------------------------------------------------------------------------------------------------------
VXD DYNAVXD DYNAMIC
SEGMENTS
_LPTEXT CLASS 'LCODE' PRELOAD NONDISCARDABLE
_LTEXT CLASS 'LCODE' PRELOAD NONDISCARDABLE
_LDATA CLASS 'LCODE' PRELOAD NONDISCARDABLE
_TEXT CLASS 'LCODE' PRELOAD NONDISCARDABLE
_DATA CLASS 'LCODE' PRELOAD NONDISCARDABLE
CONST CLASS 'LCODE' PRELOAD NONDISCARDABLE
_TLS CLASS 'LCODE' PRELOAD NONDISCARDABLE
_BSS CLASS 'LCODE' PRELOAD NONDISCARDABLE
_LMGTABLE CLASS 'MCODE' PRELOAD NONDISCARDABLE IOPL
_LMSGDATA CLASS 'MCODE' PRELOAD NONDISCARDABLE IOPL
_IMSGTABLE CLASS 'MCODE' PRELOAD DISCARDABLE IOPL
_IMSGDATA CLASS 'MCODE' PRELOAD DISCARDABLE IOPL
_ITEXT CLASS 'ICODE' DISCARDABLE
_IDATA CLASS 'ICODE' DISCARDABLE
_PTEXT CLASS 'PCODE' NONDISCARDABLE
_PMSGTABLE CLASS 'MCODE' NONDISCARDABLE IOPL
_PMSGDATA CLASS 'MCODE' NONDISCARDABLE IOPL
_PDATA CLASS 'PDATA' NONDISCARDABLE SHARED
_STEXT CLASS 'SCODE' RESIDENT
_SDATA CLASS 'SCODE' RESIDENT
_DBOSTART CLASS 'DBOCODE' PRELOAD NONDISCARDABLE CONFORMING
_DBOCODE CLASS 'DBOCODE' PRELOAD NONDISCARDABLE CONFORMING
_DBODATA CLASS 'DBOCODE' PRELOAD NONDISCARDABLE CONFORMING
_16ICODE CLASS '16ICODE' PRELOAD DISCARDABLE
_RCODE CLASS 'RCODE'
EXPORTS
DYNAVXD_DDB @1

完整例子：

下面是一段加载动态VxD并且通过DeviceIoControl API 来调用VxD内部函数的Win32应用程序的源代码。

; VxDLoader.asm
.386
.model flat,stdcall
include windows.inc
include kernel32.inc
includelib kernel32.lib
include user32.inc
includelib user32.lib
.data
AppName db "DeviceIoControl",0
VxDName db "\\.\shellmsg.vxd",0
Success db "The VxD is successfully loaded!",0
Failure db "The VxD is not loaded!",0
Unload db "The VxD is now unloaded!",0
MsgTitle db "DeviceIoControl Example",0
MsgText db "I'm called from a VxD!",0
InBuffer dd offset MsgTitle
dd offset MsgText
.data?
hVxD dd ?
.code
start:
invoke CreateFile,addr VxDName,0,0,0,0,FILE_FLAG_DELETE_ON_CLOSE,0
.if eax!=INVALID_HANDLE_VALUE
mov hVxD,eax
invoke MessageBox,NULL,addr Success,addr AppName,MB_OK+MB_ICONINFORMATION
invoke DeviceIoControl,hVxD,1,addr InBuffer,8,NULL,NULL,NULL,NULL
invoke CloseHandle,hVxD
invoke MessageBox,NULL,addr Unload,addr AppName,MB_OK+MB_ICONINFORMATION
.else
invoke MessageBox,NULL,addr Failure,NULL,MB_OK+MB_ICONERROR
.endif
invoke ExitProcess,NULL
end start