vnchooks.cpp

teamviewer source code vc++

//  Copyright (C) 2002 Ultr@VNC Team Members. All Rights Reserved.
//  Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
//  Copyright (C) 1997 AT&T Laboratories Cambridge. All Rights Reserved.
//
//  This file is part of the VNC system.
//
//  The VNC system is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
//  USA.
//
// If the source code for the VNC system is not available from the place 
// whence you received this file, check http://www.uk.research.att.com/vnc or contact
// the authors on [e-mail] for information on obtaining it.

// VNC update hook implementation.
//

#include "VNCHooks.h"

#include <stdio.h>
#include <crtdbg.h>

/////////////////////////////////////////////////////////////////////////////
// Storage for the global data in the DLL

// MSVC is bugged - if a default value is missed off from one of the following
// variables then that variable is process-specific for some reason!

/////////////////////////////////////////////////////////////////////////////
// Storage for the global data in the DLL
// Note: For Borland C++ compilers, this data segment is defined in a
//       separate file, SharedData.cpp.

#ifdef _MSC_VER

// MSVC is bugged - if a default value is missed off from one of the following
// variables then that variable is process-specific for some reason!

#pragma data_seg(".SharedData")
DWORD vnc_thread_id = 0;
UINT UpdateRectMessage = 0;
UINT CopyRectMessage = 0;
UINT MouseMoveMessage = 0;
UINT KeyMessage = 0;
HHOOK hCallWndHook = NULL;							// Handle to the CallWnd hook
HHOOK hGetMsgHook = NULL;							// Handle to the GetMsg hook
HHOOK hDialogMsgHook = NULL;						// Handle to the DialogMsg hook
HHOOK hLLKeyboardHook = NULL;						// Handle to LowLevel kbd hook
HHOOK hLLMouseHook = NULL;							// Handle to LowLevel mouse hook
HWND  hSingleWindow = NULL;
#pragma data_seg( )


#else

#include "SharedData.h"


#endif // _MSC_VER


/////////////////////////////////////////////////////////////////////////////
// Per-instance DLL variables

const char sPrefSegment[] = "Application_Prefs";
char *sModulePrefs = NULL;							// Name of the module that created us
BOOL prf_use_GetUpdateRect = TRUE;					// Use the GetUpdateRect paint mode
BOOL prf_use_Timer = FALSE;							// Use Timer events to trigger updates
BOOL prf_use_KeyPress = TRUE;						// Use keyboard events
BOOL prf_use_LButtonUp = TRUE;						// Use left mouse button up events
BOOL prf_use_MButtonUp = TRUE;						// Use middle mouse button up events
BOOL prf_use_RButtonUp = TRUE;						// Use right mouse button up events
BOOL prf_use_Deferral = TRUE;						// Use deferred updates

HINSTANCE hInstance = NULL;							// This instance of the DLL
BOOL HookMaster = FALSE;							// Is this instance WinVNC itself?

BOOL appHookedOK = FALSE;							// Did InitInstance succeed?

ULONG old_cursor = NULL;							// Current Cursor icon handle

BOOL m_ddihook;

/////////////////////////////////////////////////////////////////////////////
// Registered messages & atoms to be used by VNCHooks.DLL

// Messages
const UINT VNC_DEFERRED_UPDATE = RegisterWindowMessage("VNCHooks.Deferred.UpdateMessage");
const UINT VNC_DEFERRED_PAINTBORDER = RegisterWindowMessage("VNCHooks.Deferred.PaintBorder");

// Atoms
const char *VNC_POPUPSELN_ATOMNAME = "VNCHooks.PopUpMenu.Selected";
ATOM VNC_POPUPSELN_ATOM = NULL;

/////////////////////////////////////////////////////////////////////////////
// The DLL functions

// Forward definition of hook procedures

BOOL HookHandle(UINT msg, HWND hWnd, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK CallWndProc (int nCode, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK GetMessageProc(int nCode, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK DialogMessageProc(int nCode, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK LowLevelKeyboardFilterProc(int nCode, WPARAM wParam, LPARAM lParam);
LRESULT CALLBACK LowLevelMouseFilterProc(int nCode, WPARAM wParam, LPARAM lParam);

// Forward definition of setup and shutdown procedures
BOOL InitInstance();
BOOL ExitInstance();
void PaintBorder(HWND hwnd);

// The DLL's main procedure
BOOL WINAPI DllMain (HANDLE hInst, ULONG ul_reason_for_call, LPVOID lpReserved)
{
	// Find out why we're being called
	switch (ul_reason_for_call)
	{

	case DLL_PROCESS_ATTACH:
#ifdef _MSC_VER 
		_RPT0(_CRT_WARN, "vncHooks : Hook DLL loaded\n");
#endif

		// Save the instance handle
		hInstance = (HINSTANCE)hInst;

		// Call the initialisation function
		appHookedOK = InitInstance();

		// ALWAYS return TRUE to avoid breaking unhookable applications!!!
		return TRUE;

	case DLL_PROCESS_DETACH:
#ifdef _MSC_VER 
		_RPT0(_CRT_WARN, "vncHooks : Hook DLL unloaded\n");
#endif
		
		// Call the exit function
		// If the app failed to hook OK, ExitInstance will still operate OK (hopefully...)
		ExitInstance();

		return TRUE;

	default:
		return TRUE;
	}
}

// Function used to find out whether VNCHooks uses "reliable" or "hint" hooks
// Currently is always zero to indicate unreliable, hint hooks.
DllExport DWORD HooksType()
{
	// Unreliable "hint" hooks
	return 0;
}

// Add the new hook

DllExport BOOL SetHooks(DWORD thread_id, UINT UpdateMsg, UINT CopyMsg, UINT MouseMsg, UINT KeyMsg, BOOL ddihook)
{
	// Don't add the hook if the thread id is NULL
	if (!thread_id)
		return FALSE;
	m_ddihook=ddihook;
	
	// Remove Hooks if already set
	if (vnc_thread_id)
	{
		UnSetHooks(vnc_thread_id);
	}

	// Add the CallWnd hook
	hCallWndHook = SetWindowsHookEx(
					WH_CALLWNDPROC,					// Hook in before msg reaches app
					(HOOKPROC) CallWndProc,			// Hook procedure
					hInstance,						// This DLL instance
					0L								// Hook in to all apps
					);

	// Add the GetMessage hook
	hGetMsgHook = SetWindowsHookEx(
					WH_GETMESSAGE,					// Hook in before msg reaches app
					(HOOKPROC) GetMessageProc,			// Hook procedure
					hInstance,						// This DLL instance
					0L								// Hook in to all apps
					);

		// Add the GetMessage hook
	hDialogMsgHook = SetWindowsHookEx(
					WH_SYSMSGFILTER,				// Hook in dialogs, menus and scrollbars
					(HOOKPROC) DialogMessageProc,	// Hook procedure
					hInstance,						// This DLL instance
					0L								// Hook in to all apps
					);

	// Check that it worked
	if ((hCallWndHook != NULL) && (hGetMsgHook != NULL) && (hDialogMsgHook != NULL))
	{
		vnc_thread_id = thread_id;			// Save the WinVNC thread id
		UpdateRectMessage = UpdateMsg;		// Save the message ID to use for rectangle updates
		CopyRectMessage = CopyMsg;			// Save the message ID to use for copyrect
		MouseMoveMessage = MouseMsg;		// Save the message ID to send when mouse moves
		KeyMessage = KeyMsg;		// Save the message ID to send when pause key is pressed
		HookMaster = TRUE;					// Set the HookMaster flag for this instance
		return TRUE;
	}
	else
	{
		// Stop the keyboard hook
		SetKeyboardFilterHook(FALSE);
		SetMouseFilterHook(FALSE);

		// Kill the main hooks
		if (hCallWndHook != NULL)
			UnhookWindowsHookEx(hCallWndHook);
		if (hGetMsgHook != NULL)
			UnhookWindowsHookEx(hGetMsgHook);
		if (hDialogMsgHook != NULL)
			UnhookWindowsHookEx(hDialogMsgHook);
		hCallWndHook = NULL;
		hGetMsgHook = NULL;
		hDialogMsgHook = NULL;
	}

	// The hook failed, so return an error code
	return FALSE;

}

// EnumWindows procedure to remove the extra property we added

BOOL CALLBACK
KillPropsProc(HWND hwnd, LPARAM lParam)
{
	// Remove our custom property...
	RemoveProp(hwnd, (LPCTSTR) MAKELONG(VNC_POPUPSELN_ATOM, 0));
	return TRUE;
}

// Remove the hook from the system

DllExport BOOL UnSetHooks(DWORD thread_id)
{

	BOOL unHooked = TRUE;
	
	// Remove the extra property value from all local windows
	EnumWindows((WNDENUMPROC) &KillPropsProc, NULL);

	// Stop the keyboard & mouse hooks
	unHooked = unHooked && SetKeyboardFilterHook(FALSE);
	unHooked = unHooked && SetMouseFilterHook(FALSE);

	// Is the window handle valid?
	if (thread_id != vnc_thread_id)
		return FALSE;

	// Unhook the procs
	if (hCallWndHook != NULL)
	{
		unHooked = unHooked && UnhookWindowsHookEx(hCallWndHook);
		hCallWndHook = NULL;
	}

	if (hGetMsgHook != NULL)
	{
		unHooked = unHooked && UnhookWindowsHookEx(hGetMsgHook);
		hGetMsgHook = NULL;
	}

	if (hDialogMsgHook != NULL)
	{
		unHooked = unHooked && UnhookWindowsHookEx(hDialogMsgHook);
		hDialogMsgHook = NULL;
	}

	// If we managed to unhook then reset
	if (unHooked)
	{
		vnc_thread_id = 0;
		HookMaster = FALSE;
	}

	return unHooked;

}

// Routine to start and stop local keyboard message filtering
DllExport BOOL SetKeyboardFilterHook(BOOL activate)
{
	if (activate)
	{
#ifdef WH_KEYBOARD_LL
		if (hLLKeyboardHook == NULL)
		{
			// Start up the hook...
			hLLKeyboardHook = SetWindowsHookEx(
					WH_KEYBOARD_LL,					// Hook in before msg reaches app
					(HOOKPROC) LowLevelKeyboardFilterProc,			// Hook procedure
					hInstance,						// This DLL instance
					0L								// Hook in to all apps
					);
			if (hLLKeyboardHook == NULL)
				return FALSE;
		}
		return TRUE;
#else
#pragma message("warning:Low-Level Keyboard hook code omitted.")
		return FALSE;
#endif
	} else {
		if (hLLKeyboardHook != NULL)
		{
			// Stop the hook...
			if (!UnhookWindowsHookEx(hLLKeyboardHook))
				return FALSE;
			hLLKeyboardHook = NULL;
		}
		return TRUE;
	}
}

// Routine to start and stop local mouse message filtering
DllExport BOOL SetMouseFilterHook(BOOL activate)
{
	if (activate)
	{
#ifdef WH_MOUSE_LL
		if (hLLMouseHook == NULL)
		{
			// Start up the hook...
			hLLMouseHook = SetWindowsHookEx(
					WH_MOUSE_LL,					// Hook in before msg reaches app
					(HOOKPROC) LowLevelMouseFilterProc,			// Hook procedure
					hInstance,						// This DLL instance
					0L								// Hook in to all apps
					);
			if (hLLMouseHook == NULL)
				return FALSE;
		}
		return TRUE;
#else
#pragma message("warning:Low-Level Mouse hook code omitted.")
		return FALSE;
#endif
	} else {
		if (hLLMouseHook != NULL)
		{
			// Stop the hook...
			if (!UnhookWindowsHookEx(hLLMouseHook))
				return FALSE;
			hLLMouseHook = NULL;
		}
		return TRUE;
	}
}

// Routine to get the window's client rectangle, in screen coordinates
inline BOOL GetAbsoluteClientRect(HWND hwnd, RECT *rect)
{
	POINT topleft;
	topleft.x = 0;
	topleft.y = 0;

	// Get the client rectangle size
	if (!GetClientRect(hwnd, rect))
		return FALSE;

	// Get the client rectangle position
	if (!ClientToScreen(hwnd, &topleft))
		return FALSE;

	// Now adjust the window rectangle
	rect->left += topleft.x;
	rect->top += topleft.y;
	rect->right += topleft.x;
	rect->bottom += topleft.y;

	return TRUE;
}

// Routine to send an UpdateRect message to WinVNC
inline void SendUpdateRect(SHORT x, SHORT y, SHORT x2, SHORT y2)
{
	WPARAM vwParam;
	LPARAM vlParam;

	vwParam = MAKELONG(x, y);
	vlParam = MAKELONG(x2, y2);

	// Send the update to WinVNC
	PostThreadMessage(
		vnc_thread_id,
		UpdateRectMessage,
		vwParam,
		vlParam
		);
	HWND hWndRemote=FindWindow("WinVNC desktop sink", "WinVNC");
	if (hWndRemote==NULL) UnSetHooks(vnc_thread_id);
}

// Send a window's position to WinVNC

inline void SendWindowRect(HWND hWnd)
{
	RECT wrect;

	// Get the rectangle position
	if (IsWindowVisible(hWnd) && GetWindowRect(hWnd, &wrect))
	{
		// Send the position
		SendUpdateRect(
			(SHORT) wrect.left,
			(SHORT) wrect.top,
			(SHORT) wrect.right,
			(SHORT) wrect.bottom
			);
	}
}

// Send a deferred message into this Window's message queue, so that
// we'll intercept it again only after the message that triggered it has been
// handled

inline void SendDeferredUpdateRect(HWND hWnd, SHORT x, SHORT y, SHORT x2, SHORT y2)
{
	WPARAM vwParam;
	LPARAM vlParam;

	vwParam = MAKELONG(x, y);
	vlParam = MAKELONG(x2, y2);

	if (prf_use_Deferral)
	{
		// Send the update back to the window
		PostMessage(
			hWnd,
			VNC_DEFERRED_UPDATE,
			vwParam,
			vlParam
			);
	}
	else
	{
		// Send the update to WinVNC
		PostThreadMessage(
			vnc_thread_id,
			UpdateRectMessage,
			vwParam,
			vlParam
			);
	}
}

inline void SendDeferredWindowRect(HWND hWnd)
{
	RECT wrect;

	// Get the rectangle position
	if (IsWindowVisible(hWnd) && GetWindowRect(hWnd, &wrect))
	{
		// Send the position
		SendDeferredUpdateRect(
			hWnd,
			(SHORT) wrect.left,
			(SHORT) wrect.top,
			(SHORT) wrect.right,