Windows NT Driver >> Pascal >> IOCTL
METHOD_IN_DIRECT、METHOD_OUT_DIRECT
參考資訊:
1. Source Code
2. delphidriverdevelopmentkit
METHOD_IN_DIRECT、METHOD_OUT_DIRECT的概念就是直接Mapping User Buffer,然後驅動程式使用該Mapped的MDL(Memory Description List)操作,相較於METHOD_BUFFERED,因為不須I/O Manager更新回User Buffer>,因此,效率會比較好,而相比File的DO_DIRECT_IO,IOCTL細分成IN和OUT兩種,這是因為IOCTL有區分Input和Output Buffer的緣故,因此,會有方向性的考量,Microsoft針對這部份的描述,僅說明MDL描述會有讀>寫存取方向的區分,但是司徒實際測試,發現DeviceIoControl()的Input和Output Buffer是可以混用的,意思就是Input Buffer可以充當Input或Output Buffer使用,而Output Buffer也可以充當Input或Output Buffer使用,只要驅動程式跟User Application定義好即可,當然,METHOD_IN_DIRECT和METHOD_OUT_DIRECT也是可以混用的,關於這部份的細節,有興趣的使用者可以研讀WRK代碼,不過,深怕未知問題可能發生,建議還是依照Microsoft規定去撰寫驅動程式會比較保險。
Microsoft針對I/O部份的說明:
buffer-descriptions-for-i-o-control-codes
記憶體指標:
Buffer | Length | |
---|---|---|
Input | (Irp) AssociatedIrp.SystemBuffer |
(IrpStack) Parameters.DeviceIoControl.InputBufferLength |
Output | (MDL) MmGetSystemAddressForMdlSafe |
(IrpStack) Parameters.DeviceIoControl.OutputBufferLength |
main.pas
unit main; interface uses DDDK; const DEV_NAME = '\Device\MyDriver'; SYM_NAME = '\DosDevices\MyDriver'; IOCTL_SET = $222001; // CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_IN_DIRECT, FILE_ANY_ACCESS) IOCTL_GET = $222006; // CTL_CODE(FILE_DEVICE_UNKNOWN, 0x801, METHOD_OUT_DIRECT, FILE_ANY_ACCESS) function _DriverEntry(pOurDriver:PDriverObject; pOurRegistry:PUnicodeString):NTSTATUS; stdcall; implementation var szBuffer: array[0..255] of char; function IrpOpen(pOurDevice:PDeviceObject; pIrp:PIrp):NTSTATUS; stdcall; begin DbgPrint('IRP_MJ_CREATE', []); Result:= STATUS_SUCCESS; pIrp^.IoStatus.Information:= 0; pIrp^.IoStatus.Status:= Result; IoCompleteRequest(pIrp, IO_NO_INCREMENT); end; function IrpClose(pOurDevice:PDeviceObject; pIrp:PIrp):NTSTATUS; stdcall; begin DbgPrint('IRP_MJ_CLOSE', []); Result:= STATUS_SUCCESS; pIrp^.IoStatus.Information:= 0; pIrp^.IoStatus.Status:= Result; IoCompleteRequest(pIrp, IO_NO_INCREMENT); end; function IrpIOCTL(pOurDevice:PDeviceObject; pIrp:PIrp):NTSTATUS; stdcall; var len: ULONG; dst: PChar; code: ULONG; psk: PIoStackLocation; begin len:= 0; psk:= IoGetCurrentIrpStackLocation(pIrp); code:= psk^.Parameters.DeviceIoControl.IoControlCode; case code of IOCTL_GET:begin DbgPrint('IOCTL_GET', []); len:= strlen(@szBuffer[0])+1; dst:= MmGetSystemAddressForMdlSafe(pIrp^.MdlAddress, LowPagePriority); memcpy(dst, @szBuffer[0], len); end; IOCTL_SET:begin DbgPrint('IOCTL_SET', []); len:= psk^.Parameters.DeviceIoControl.InputBufferLength; memcpy(@szBuffer[0], pIrp^.AssociatedIrp.SystemBuffer, len); DbgPrint('Buffer: %s, Length: %d', [szBuffer, len]); end; end; Result:= STATUS_SUCCESS; pIrp^.IoStatus.Information:= len; pIrp^.IoStatus.Status:= Result; IoCompleteRequest(pIrp, IO_NO_INCREMENT); end; procedure Unload(pOurDriver:PDriverObject); stdcall; var szSymName: TUnicodeString; begin RtlInitUnicodeString(@szSymName, SYM_NAME); IoDeleteSymbolicLink(@szSymName); IoDeleteDevice(pOurDriver^.DeviceObject); end; function _DriverEntry(pOurDriver:PDriverObject; pOurRegistry:PUnicodeString):NTSTATUS; stdcall; var suDevName: TUnicodeString; szSymName: TUnicodeString; pOurDevice: PDeviceObject; begin RtlInitUnicodeString(@suDevName, DEV_NAME); RtlInitUnicodeString(@szSymName, SYM_NAME); Result:= IoCreateDevice(pOurDriver, 0, @suDevName, FILE_DEVICE_UNKNOWN, 0, FALSE, pOurDevice); if NT_SUCCESS(Result) then begin pOurDriver^.MajorFunction[IRP_MJ_CREATE]:= @IrpOpen; pOurDriver^.MajorFunction[IRP_MJ_CLOSE] := @IrpClose; pOurDriver^.MajorFunction[IRP_MJ_DEVICE_CONTROL] := @IrpIOCTL; pOurDriver^.DriverUnload := @Unload; pOurDevice^.Flags:= pOurDevice^.Flags or DO_BUFFERED_IO; pOurDevice^.Flags:= pOurDevice^.Flags and not DO_DEVICE_INITIALIZING; Result:= IoCreateSymbolicLink(@szSymName, @suDevName); end; end; end.
IrpIOCTL()收到IOCTL_SET時,Driver複製User Buffer的內容到szBuffer,而收到IOCTL_GET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OutBufferSize回傳的長度。
app.pas
program main; {$APPTYPE CONSOLE} uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, DIALOGS; const METHOD_BUFFERED = 0; METHOD_IN_DIRECT = 1; METHOD_OUT_DIRECT = 2; FILE_ANY_ACCESS = 0; FILE_DEVICE_UNKNOWN = $22; var fd: DWORD; ret: DWORD; len: DWORD; buf: array[0..255] of char; set_code: DWORD; get_code: 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 StrCopy(buf, 'I am error'); len:= strlen(buf)+1; set_code:= (FILE_DEVICE_UNKNOWN shl 16) or (FILE_ANY_ACCESS shl 14) or ($800 shl 2) or (METHOD_IN_DIRECT); get_code:= (FILE_DEVICE_UNKNOWN shl 16) or (FILE_ANY_ACCESS shl 14) or ($801 shl 2) or (METHOD_OUT_DIRECT); DeviceIoControl(fd, set_code, @buf, len, Nil, 0, ret, Nil); WriteLn(Output, Format('SET: %s, %d', [buf, len])); FillChar(buf, sizeof(buf), #0); DeviceIoControl(fd, get_code, Nil, 0, @buf, len, ret, Nil); WriteLn(Output, Format('GET: %s, %d', [buf, ret])); CloseHandle(fd); end else begin WriteLn(Output, 'failed to open mydriver'); end; end.
結果