Kernel Mode Driver Framework >> Pascal (PNP)

Thread

---

參考資訊：
1. Source Code
2. operating-system-ch4-multithread
3. user-level-threads-and-kernel-level-threads

Thread是一個最小的執行單位，一個Process可以產生多個Thread，在多核CPU上，產生的Thread可以同時的運作，這意謂著使用Thread技術可以用來改善效能，但是，每個Thread間的資料同步則是另一個課題，在此練習，司徒著重在教導使用者如何撰寫一個最基本的Thread，了解其架構後，使用者可以再更深入了解Thread需要面對的其它問題，而值得注意的是，Thread有區分User Thread和System Thread兩種，各有優缺點，細節可以參考如上的參考資訊。

main.pas

unit main;

interface
  uses
    DDDK;
    
  const
    DEV_NAME = '\Device\MyDriver';
    SYM_NAME = '\DosDevices\MyDriver';
    IOCTL_START = (FILE_DEVICE_UNKNOWN shl 16) or (FILE_ANY_ACCESS shl 14) or ($800 shl 2) or (METHOD_BUFFERED);
    IOCTL_STOP = (FILE_DEVICE_UNKNOWN shl 16) or (FILE_ANY_ACCESS shl 14) or ($801 shl 2) or (METHOD_BUFFERED);

  function __DriverEntry(pOurDriver:PDRIVER_OBJECT; pOurRegistry:PUNICODE_STRING):NTSTATUS; stdcall;

implementation
var
  bExit: ULONG;
  pThread: Handle;

procedure MyThread(pParam:Pointer); stdcall;
var
  tt: LARGE_INTEGER;
 
begin
  tt.HighPart:= tt.HighPart or -1;
  tt.LowPart:= ULONG(-10000000);
  while Integer(bExit) = 0 do
  begin
    KeDelayExecutionThread(KernelMode, FALSE, @tt);
    DbgPrint('Sleep 1s', []);
  end;
  DbgPrint('Exit MyThread', []);
  PsTerminateSystemThread(STATUS_SUCCESS);
end;

procedure IrpFileCreate(Device:WDFDEVICE; Request:WDFREQUEST; FileObject:WDFFILEOBJECT); stdcall;
begin
  DbgPrint('IrpFileCreate', []);
  WdfRequestComplete(Request, STATUS_SUCCESS);
end;

procedure IrpFileClose(FileObject:WDFFILEOBJECT); stdcall;
begin
  DbgPrint('IrpFileClose', []);
end;

procedure IrpIOCTL(Queue:WDFQUEUE; Request:WDFREQUEST; OutputBufferLength:ULONG; InputBufferLength:ULONG; IoControlCode:ULONG); stdcall;
var
  hThread: Handle;
  status: NTSTATUS;

begin
  if IoControlCode = IOCTL_START then begin
    DbgPrint('IOCTL_START', []);
    bExit:= 0;
    status:= PsCreateSystemThread(@hThread, THREAD_ALL_ACCESS, Nil, Handle(-1), Nil, MyThread, Nil);
    if NT_SUCCESS(status) then begin
      ObReferenceObjectByHandle(hThread, THREAD_ALL_ACCESS, Nil, KernelMode, @pThread, Nil);
      ZwClose(hThread);
    end;
  end
  else if IoControlCode = IOCTL_STOP then begin
    DbgPrint('IOCTL_STOP', []);
    bExit:= 1;
    KeWaitForSingleObject(Pointer(pThread), Executive, KernelMode, False, Nil);
    ObDereferenceObject(pThread);
  end;
  WdfRequestComplete(Request, STATUS_SUCCESS);
end;

function AddDevice(pOurDriver:WDFDRIVER; pDeviceInit:PWDFDEVICE_INIT):NTSTATUS; stdcall;
var
  device: WDFDEVICE;
  suDevName: UNICODE_STRING;
  szSymName: UNICODE_STRING;
  file_cfg: WDF_FILEOBJECT_CONFIG;
  ioqueue_cfg: WDF_IO_QUEUE_CONFIG;

begin
  WdfDeviceInitSetIoType(pDeviceInit, WdfDeviceIoBuffered);
  WDF_FILEOBJECT_CONFIG_INIT(@file_cfg, @IrpFileCreate, @IrpFileClose, Nil);
  WdfDeviceInitSetFileObjectConfig(pDeviceInit, @file_cfg, WDF_NO_OBJECT_ATTRIBUTES);
  
  RtlInitUnicodeString(@suDevName, DEV_NAME);
  RtlInitUnicodeString(@szSymName, SYM_NAME);
  WdfDeviceInitAssignName(pDeviceInit, @suDevName);
  WdfDeviceCreate(@pDeviceInit, WDF_NO_OBJECT_ATTRIBUTES, @device);
  WdfDeviceCreateSymbolicLink(device, @szSymName);
  
  WDF_IO_QUEUE_CONFIG_INIT_DEFAULT_QUEUE(@ioqueue_cfg, WdfIoQueueDispatchSequential);
  ioqueue_cfg.EvtIoDeviceControl:= @IrpIOCTL;
  Result:= WdfIoQueueCreate(device, @ioqueue_cfg, WDF_NO_OBJECT_ATTRIBUTES, WDF_NO_HANDLE);
end;

function __DriverEntry(pOurDriver:PDRIVER_OBJECT; pOurRegistry:PUNICODE_STRING):NTSTATUS; stdcall;
var
  config: WDF_DRIVER_CONFIG;
  
begin
  WDF_DRIVER_CONFIG_INIT(@config, AddDevice);
  WdfDriverCreate(pOurDriver, pOurRegistry, WDF_NO_OBJECT_ATTRIBUTES, @config, WDF_NO_HANDLE);
  Result:= STATUS_SUCCESS;
end;
end.

IrpIOCTL收到IOCTL_START後，產生一個新的Thread(注意有User和System區分)，接著呼叫ZwClose()，值得注意的是，這個ZwClose()僅是釋放Handle的資源，實際Thread並不會被關閉，原因在於提前做ObReferenceObjectByHandle()，而當收到IOCTL_STOP，則設定bExit並等待Thread結束，最後呼叫ObDereferenceObject()釋放Object資源。

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;
  METHOD_NEITHER = 3;
  FILE_ANY_ACCESS = 0;
  FILE_DEVICE_UNKNOWN = $22;
  IOCTL_START = (FILE_DEVICE_UNKNOWN shl 16) or (FILE_ANY_ACCESS shl 14) or ($800 shl 2) or (METHOD_BUFFERED);
  IOCTL_STOP = (FILE_DEVICE_UNKNOWN shl 16) or (FILE_ANY_ACCESS shl 14) or ($801 shl 2) or (METHOD_BUFFERED);

var
  fd: DWORD;
  ret: DWORD;

begin
  fd:= CreateFile('\\.\MyDriver', GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ, Nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  if (fd <>l INVALID_HANDLE_VALUE) then
  begin
    DeviceIoControl(fd, IOCTL_START, Nil, 0, Nil, 0, ret, Nil);
    Sleep(3000);
    DeviceIoControl(fd, IOCTL_STOP, Nil, 0, Nil, 0, ret, Nil);
    CloseHandle(fd);
  end else
  begin
    WriteLn(Output, 'failed to open mydriver');
  end;
end.

結果

返回上一頁