Windows Driver Model >> Pascal >> IOCTL
IRP
參考資訊:
1. Source Code
2. delphidriverdevelopmentkit
Input Output Control(IOCTL)是另一種可以跟驅動程式溝通的方式,本身帶有命令參數,驅動程式可以依據不一樣的命令做不一樣的事情,而除了命令以外,IOCTL更把Buffer切成Input和Output兩塊,單一次命令的運作就可以完成讀寫的動作,Buffer的屬性也是需要做設定才可以使用,分為Buffered、Direct和Neither這三種設定方式,感覺是不是跟File的Buffer設定方式很相似呢?沒錯,基本上是一樣的,雖然司徒講得有點複雜,不過,只要把Buffer的設定方式搞懂後,使用者就可以發現,整個運作原理是相當容易理解的。
當然,使用者可能好奇,IRP_MJ_READ和IRP_MJ_WRITE是否可以取代IRP_MJ_DEVICE_CONTROL的功能呢?答案:肯定是可以的,只要把資料做編碼,功能上是可以取代的,只是這樣的作法,把控制應用以及大量傳輸的概念都綁在一起,失去原有的設計本質,因此,如果以資料為傳輸目的,建議使用IRP_MJ_READ和IRQP_MJ_WRITE,而以控制應用為目的時,則建議使用IRP_MJ_DEVICE_CONTROL的方式。
至於IOCTL命令到底是什麼東西呢?其實就是一個編碼後的32Bit的數值,欄位如下所示:
#define CTL_CODE(DeviceType, Function, Transfer, Access) (((DeviceType) << 16) | ((Access) << 14) | ((Function) << 2) | (Transfer))
表格如下:
Ref. defining-i-o-control-codes
透過Microsoft的Macro(CTL_CODE)定義該數值,說穿了,只要App跟驅動程式都可以互相知道對方的意思(IOCTL命令)就可以,當然有一些是Microsoft定義保留的Global IOCTL,在使用上,需要特別注意一下。
對應的溝通管道:
Win32 API | Kernel IRP |
---|---|
CreateFile() | IRP_MJ_CREATE |
DeviceIoControl() | IRP_MJ_DEVICE_CONTROL |
CloseFile() | IRP_MJ_CLOSE |
取得方式:
IOCTL Code |
---|
(IrpStack) Parameters.DeviceIoControl.IoControlCode |
main.pas
unit main; interface uses DDDK; const DEV_NAME = '\Device\MyDriver'; SYM_NAME = '\DosDevices\MyDriver'; IOCTL_TEST = (FILE_DEVICE_UNKNOWN shl 16) or ($800 shl 2) or (FILE_ANY_ACCESS shl 14) or (METHOD_BUFFERED); function _DriverEntry(pOurDriver:PDRIVER_OBJECT; pOurRegistry:PUNICODE_STRING):NTSTATUS; stdcall; implementation var pNextDevice: PDEVICE_OBJECT; szBuf: array[0..255] of char; procedure Unload(pOurDriver:PDRIVER_OBJECT); stdcall; begin end; function IrpFile(pOurDevice:PDEVICE_OBJECT; pIrp:PIRP):NTSTATUS; stdcall; var psk: PIO_STACK_LOCATION; begin psk:= IoGetCurrentIrpStackLocation(pIrp); case psk^.MajorFunction of IRP_MJ_CREATE: DbgPrint('IRP_MJ_CREATE', []); IRP_MJ_CLOSE: DbgPrint('IRP_MJ_CLOSE', []); end; Result:= STATUS_SUCCESS; pIrp^.IoStatus.Status:= Result; pIrp^.IoStatus.Information:= 0; IoCompleteRequest(pIrp, IO_NO_INCREMENT); end; function IrpIOCTL(pOurDevice:PDeviceObject; pIrp:PIrp):NTSTATUS; stdcall; var code: ULONG; psk: PIO_STACK_LOCATION; begin psk:= IoGetCurrentIrpStackLocation(pIrp); code:= psk^.Parameters.DeviceIoControl.IoControlCode; case code of IOCTL_TEST: begin DbgPrint('IOCTL_TEST', []); end; end; Result:= STATUS_SUCCESS; pIrp^.IoStatus.Information:= 0; pIrp^.IoStatus.Status:= Result; IoCompleteRequest(pIrp, IO_NO_INCREMENT); end; function IrpPnp(pOurDevice:PDEVICE_OBJECT; pIrp:PIRP):NTSTATUS; stdcall; var psk: PIO_STACK_LOCATION; suSymName: UNICODE_STRING; begin psk:= IoGetCurrentIrpStackLocation(pIrp); if psk^.MinorFunction = IRP_MN_REMOVE_DEVICE then begin RtlInitUnicodeString(@suSymName, SYM_NAME); IoDetachDevice(pNextDevice); IoDeleteDevice(pOurDevice); IoDeleteSymbolicLink(@suSymName); end; IoSkipCurrentIrpStackLocation(pIrp); Result:= IoCallDriver(pNextDevice, pIrp); end; function AddDevice(pOurDriver:PDRIVER_OBJECT; pPhyDevice:PDEVICE_OBJECT):NTSTATUS; stdcall; var suDevName: UNICODE_STRING; suSymName: UNICODE_STRING; pOurDevice: PDEVICE_OBJECT; begin RtlInitUnicodeString(@suDevName, DEV_NAME); RtlInitUnicodeString(@suSymName, SYM_NAME); IoCreateDevice(pOurDriver, 0, @suDevName, FILE_DEVICE_UNKNOWN, 0, FALSE, pOurDevice); pNextDevice:= IoAttachDeviceToDeviceStack(pOurDevice, pPhyDevice); pOurDevice^.Flags:= pOurDevice^.Flags or DO_BUFFERED_IO; pOurDevice^.Flags:= pOurDevice^.Flags and not DO_DEVICE_INITIALIZING; Result:= IoCreateSymbolicLink(@suSymName, @suDevName); end; function _DriverEntry(pOurDriver:PDRIVER_OBJECT; pOurRegistry:PUNICODE_STRING):NTSTATUS; stdcall; begin pOurDriver^.MajorFunction[IRP_MJ_PNP]:= @IrpPnp; pOurDriver^.MajorFunction[IRP_MJ_CREATE]:= @IrpFile; pOurDriver^.MajorFunction[IRP_MJ_CLOSE]:= @IrpFile; pOurDriver^.MajorFunction[IRP_MJ_DEVICE_CONTROL] := @IrpIOCTL; pOurDriver^.DriverExtension^.AddDevice:=@AddDevice; pOurDriver^.DriverUnload:=@Unload; Result:=STATUS_SUCCESS; end; end.
IrpIOCTL()僅列印IOCTL_TEST命令。
app.pas
program main; {$APPTYPE CONSOLE} uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, DIALOGS; const METHOD_BUFFERED = 0; FILE_ANY_ACCESS = 0; FILE_DEVICE_UNKNOWN = $22; IOCTL_TEST = (FILE_DEVICE_UNKNOWN shl 16) or ($800 shl 2) or (FILE_ANY_ACCESS shl 14) or (METHOD_BUFFERED); var fd: DWORD; dwRet: DWORD; begin fd:= CreateFile('\\.\MyDriver', GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ, Nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); if (fd <> INVALID_HANDLE_VALUE) then begin DeviceIoControl(fd, IOCTL_TEST, Nil, 0, Nil, 0, dwRet, Nil); CloseHandle(fd); end else begin WriteLn(Output, 'failed to open mydriver'); end; end.
結果