程式師世界 >> 編程語言 >> 更多編程語言 >> Delphi >> Delphi研究之驅動開發篇（七）--利用共享內存與用戶模式程序通訊(上)

Delphi研究之驅動開發篇（七）--利用共享內存與用戶模式程序通訊(上)

編輯：Delphi

作者: mickeylan
時間: 2008-06-16,11:33
鏈接: http://bbs.pediy.com/showthread.php?t=66661

上篇教程我們學習了通過Section在用戶進程和內核驅動程序之間共享信息的方法，但是這種方法有一個缺點，就是驅動程序被硬性限制在具體進程的地址上下文中，即驅動程序所使用的虛擬地址位於此進程的地址空間中。我們在本例中使用的方法將沒有這個缺點。對於驅動程序來說，這種方法更為自然些。
首先來看看驅動程序。

代碼:unit SharingMemory;

interface

uses
nt_status, ntoskrnl, native, winioctl, fcall, macros;

function _DriverEntry(pDriverObject:PDRIVER_OBJECT; pusRegistryPath:PUNICODE_STRING): NTSTATUS; stdcall;

implementation

uses
seh;

var
     g_pSharedMemory: PVOID;
     g_pMdl: PVOID;
     g_pUserAddress: PVOID;
     g_fTimerStarted: boolean;
     g_usDeviceName, g_usSymbolicLinkName: UNICODE_STRING;

{更新系統時間到共享內存}
procedure UpdateTime; stdcall;
var
     SysTime:LARGE_INTEGER;
begin
     KeQuerySystemTime(@SysTime);
     ExSystemTimeToLocalTime(@SysTime, g_pSharedMemory);
end;

procedure TimerRoutine(pDeviceObject:PDEVICE_OBJECT; pContext:PVOID); stdcall;
begin
UpdateTime;
end;

{清理過程--釋放資源}
procedure Cleanup(pDeviceObject:PDEVICE_OBJECT); stdcall;
begin
     if g_fTimerStarted then
     begin
       IoStopTimer(pDeviceObject);
       DbgPrint(SharingMemory: Timer stopped#13#10);
     end;

     if (g_pUserAddress <> nil) and (g_pMdl <> nil) then
     begin
       MmUnmapLockedPages(g_pUserAddress, g_pMdl);
       DbgPrint(SharingMemory: Memory at address %08X unmapped#13#10,
                g_pUserAddress);
       g_pUserAddress := nil;
     end;

     if g_pMdl <> nil then
     begin
       IoFreeMdl(g_pMdl);
       DbgPrint(SharingMemory: MDL at address %08X freed#13#10,
                g_pMdl);
       g_pMdl := nil;
     end;

     if g_pSharedMemory <> nil then
     begin
       ExFreePool(g_pSharedMemory);
       DbgPrint(SharingMemory: Memory at address %08X released#13#10,
                g_pSharedMemory);
       g_pSharedMemory := nil;
     end;
end;

function DispatchCleanup(pDeviceObject:PDEVICE_OBJECT; p_Irp:PIRP): NTSTATUS; stdcall;
begin
DbgPrint(#13#10SharingMemory: Entering DispatchCleanup#13#10);
Cleanup(pDeviceObject);

     p_Irp^.IoStatus.Status := STATUS_SUCCESS;
     p_Irp^.IoStatus.Information := 0;
     IofCompleteRequest(p_Irp, IO_NO_INCREMENT);

DbgPrint(SharingMemory: Leaving DispatchCleanup#13#10);
result := STATUS_SUCCESS;
end;

function DispatchCreateClose(p_DeviceObject:PDEVICE_OBJECT; p_Irp:PIRP): NTSTATUS; stdcall;
begin
p_Irp^.IoStatus.Status := STATUS_SUCCESS;
p_Irp^.IoStatus.Information := 0;

IofCompleteRequest(p_Irp, IO_NO_INCREMENT);

result := STATUS_SUCCESS;
end;