vncservice.cpp

realvnc是一个非常流行的远程控制程序

// Static routine to simulate Ctrl-Alt-Del locally

BOOL
vncService::SimulateCtrlAltDel()
{
	vnclog.Print(LL_ALL, VNCLOG("preparing to generate ctrl-alt-del\n"));

	// Are we running on NT?
	if (IsWinNT())
	{
		vnclog.Print(LL_ALL, VNCLOG("spawn ctrl-alt-del thread...\n"));

		// *** This is an unpleasant hack.  Oh dear.

		// I simulate CtrAltDel by posting a WM_HOTKEY message to all
		// the windows on the Winlogon desktop.
		// This requires that the current thread is part of the Winlogon desktop.
		// But the current thread has hooks set & a window open, so it can't
		// switch desktops, so I instead spawn a new thread & let that do the work...

		omni_thread *thread = omni_thread::create(SimulateCtrlAltDelThreadFn);
		if (thread == NULL)
			return FALSE;
		thread->join(NULL);

		return TRUE;
	}

	return TRUE;
}

// Static routine to lock a 2K or above workstation

BOOL
vncService::LockWorkstation()
{
	if (!IsWinNT()) {
		vnclog.Print(LL_INTERR, VNCLOG("unable to lock workstation - not NT\n"));
		return FALSE;
	}

	vnclog.Print(LL_ALL, VNCLOG("locking workstation\n"));

	// Load the user32 library
	HMODULE user32 = LoadLibrary("user32.dll");
	if (!user32) {
		vnclog.Print(LL_INTERR, VNCLOG("unable to load User32 DLL (%u)\n"), GetLastError());
		return FALSE;
	}

	// Get the LockWorkstation function
	typedef BOOL (*LWProc) ();
	LWProc lockworkstation = (LWProc)GetProcAddress(user32, "LockWorkStation");
	if (!lockworkstation) {
		vnclog.Print(LL_INTERR, VNCLOG("unable to locate LockWorkStation - requires Windows 2000 or above (%u)\n"), GetLastError());
		FreeLibrary(user32);
		return FALSE;
	}
	
	// Attempt to lock the workstation
	BOOL result = (lockworkstation)();

	if (!result) {
		vnclog.Print(LL_INTERR, VNCLOG("call to LockWorkstation failed\n"));
		FreeLibrary(user32);
		return FALSE;
	}

	FreeLibrary(user32);
	return result;
}

// Static routine to show the Properties dialog for a currently-running
// copy of WinVNC, (usually a servicified version.)

BOOL
vncService::ShowProperties()
{
	// Post to the WinVNC menu window
	if (!PostToWinVNC(MENU_PROPERTIES_SHOW, 0, 0))
	{
		MessageBox(NULL, "No existing instance of WinVNC could be contacted", szAppName, MB_ICONEXCLAMATION | MB_OK);
		return FALSE;
	}

	return TRUE;
}

// Static routine to show the Default Properties dialog for a currently-running
// copy of WinVNC, (usually a servicified version.)

BOOL
vncService::ShowDefaultProperties()
{
	// Post to the WinVNC menu window
	if (!PostToWinVNC(MENU_DEFAULT_PROPERTIES_SHOW, 0, 0))
	{
		MessageBox(NULL, "No existing instance of WinVNC could be contacted", szAppName, MB_ICONEXCLAMATION | MB_OK);
		return FALSE;
	}

	return TRUE;
}

// Static routine to show the About dialog for a currently-running
// copy of WinVNC, (usually a servicified version.)

BOOL
vncService::ShowAboutBox()
{
	// Post to the WinVNC menu window
	if (!PostToWinVNC(MENU_ABOUTBOX_SHOW, 0, 0))
	{
		MessageBox(NULL, "No existing instance of WinVNC could be contacted", szAppName, MB_ICONEXCLAMATION | MB_OK);
		return FALSE;
	}

	return TRUE;
}

// Static routine to tell a locally-running instance of the server
// to connect out to a new client

BOOL
vncService::PostAddNewClient(unsigned long ipaddress)
{
	// Post to the WinVNC menu window
	if (!PostToWinVNC(MENU_ADD_CLIENT_MSG, 0, ipaddress))
	{
		MessageBox(NULL, "No existing instance of WinVNC could be contacted", szAppName, MB_ICONEXCLAMATION | MB_OK);
		return FALSE;
	}

	return TRUE;
}

// SERVICE-MODE ROUTINES

// Service-mode defines:

// Executable name
#define VNCAPPNAME            "winvnc"

// Internal service name
#define VNCSERVICENAME        "winvnc"

// Displayed service name
#define VNCSERVICEDISPLAYNAME "VNC Server"

// List of other required services ("dependency 1\0dependency 2\0\0")
// *** These need filling in properly
#define VNCDEPENDENCIES       ""

// Internal service state
SERVICE_STATUS          g_srvstatus;       // current status of the service
SERVICE_STATUS_HANDLE   g_hstatus;
DWORD                   g_error = 0;
DWORD					g_servicethread = NULL;
char*                   g_errortext[256];

// Forward defines of internal service functions
void WINAPI ServiceMain(DWORD argc, char **argv);

void ServiceWorkThread(void *arg);
void ServiceStop();
void WINAPI ServiceCtrl(DWORD ctrlcode);

bool WINAPI CtrlHandler (DWORD ctrltype);

BOOL ReportStatus(DWORD state, DWORD exitcode, DWORD waithint);

// ROUTINE TO QUERY WHETHER THIS PROCESS IS RUNNING AS A SERVICE OR NOT

BOOL	g_servicemode = FALSE;

BOOL
vncService::RunningAsService()
{
	return g_servicemode;
}

BOOL
vncService::KillRunningCopy()
{
	// Locate the hidden WinVNC menu window
	HWND hservwnd;

	while ((hservwnd = FindWindow(MENU_CLASS_NAME, NULL)) != NULL)
	{
		// Post the message to WinVNC
		PostMessage(hservwnd, WM_CLOSE, 0, 0);

		omni_thread::sleep(1);
	}

	return TRUE;
}


// ROUTINE TO POST THE HANDLE OF THE CURRENT USER TO THE RUNNING WINVNC, IN ORDER
// THAT IT CAN LOAD THE APPROPRIATE SETTINGS.  THIS IS USED ONLY BY THE SVCHELPER
// OPTION, WHEN RUNNING UNDER NT
BOOL
vncService::PostUserHelperMessage()
{
	// - Check the platform type
	if (!IsWinNT())
		return TRUE;

	// - Get the current process ID
	DWORD processId = GetCurrentProcessId();

	// - Post it to the existing WinVNC
  int retries = 6;
	while (!PostToWinVNC(MENU_SERVICEHELPER_MSG, 0, (LPARAM)processId) && retries--)
    omni_thread::sleep(10);

	// - Wait until it's been used
	omni_thread::sleep(5);

	return retries;
}

// ROUTINE TO PROCESS AN INCOMING INSTANCE OF THE ABOVE MESSAGE
BOOL
vncService::ProcessUserHelperMessage(WPARAM wParam, LPARAM lParam) {
	// - Check the platform type
	if (!IsWinNT() || !vncService::RunningAsService())
		return TRUE;

	// - Close the HKEY_CURRENT_USER key, to force NT to reload it for the new user
	// NB: Note that this is _really_ dodgy if ANY other thread is accessing the key!
	if (RegCloseKey(HKEY_CURRENT_USER) != ERROR_SUCCESS) {
		vnclog.Print(LL_INTERR, VNCLOG("failed to close current registry hive\n"));
		return FALSE;
	}

	// - Revert to our own identity
	RevertToSelf();
	g_impersonating_user = FALSE;

	// - Open the specified process
	HANDLE processHandle = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, (DWORD)lParam);
	if (processHandle == NULL) {
		vnclog.Print(LL_INTERR, VNCLOG("failed to open specified process(%d)\n"), GetLastError());
		return FALSE;
	}

	// - Get the token for the given process
	HANDLE userToken = NULL;
	if (!OpenProcessToken(processHandle, TOKEN_QUERY | TOKEN_DUPLICATE | TOKEN_IMPERSONATE, &userToken)) {
		vnclog.Print(LL_INTERR, VNCLOG("failed to get user token(%d)\n"), GetLastError());
		CloseHandle(processHandle);
		return FALSE;
	}
	CloseHandle(processHandle);

	// - Set this thread to impersonate them
	if (!ImpersonateLoggedOnUser(userToken)) {
		vnclog.Print(LL_INTERR, VNCLOG("failed to impersonate user(%d)\n"), GetLastError());
		CloseHandle(userToken);
		return FALSE;
	}
	CloseHandle(userToken);

	g_impersonating_user = TRUE;
	vnclog.Print(LL_INTINFO, VNCLOG("impersonating logged on user\n"));
	return TRUE;
}

// SERVICE MAIN ROUTINE
int
vncService::WinVNCServiceMain()
{
	typedef DWORD (WINAPI * RegisterServiceProc)(DWORD, DWORD);
	const ULONG RSP_SIMPLE_SERVICE = 0x00000001;
	const ULONG RSP_UNREGISTER_SERVICE = 0x00000000;

	g_servicemode = TRUE;

	// How to run as a service depends upon the OS being used
	switch (g_platform_id)
	{

		// Windows 95/98
	case VER_PLATFORM_WIN32_WINDOWS:
		{
			// Obtain a handle to the kernel library
			HINSTANCE kerneldll = LoadLibrary("KERNEL32.DLL");
			if (kerneldll == NULL)
				break;

			// And find the RegisterServiceProcess function
			RegisterServiceProc RegisterService;
			RegisterService = (RegisterServiceProc) GetProcAddress(kerneldll, "RegisterServiceProcess");
			if (RegisterService == NULL)
				break;
			
			// Register this process with the OS as a service!
			RegisterService(NULL, RSP_SIMPLE_SERVICE);

			// Run the service itself
			WinVNCAppMain();

			// Then remove the service from the system service table
			RegisterService(NULL, RSP_UNREGISTER_SERVICE);

			// Free the kernel library
			FreeLibrary(kerneldll);

			// *** If we don't kill the process directly here, then 
			// for some reason, WinVNC crashes...
			// *** Is this now fixed (with the stdcall patch above)?
			//ExitProcess(0);
		}
		break;

		// Windows NT
	case VER_PLATFORM_WIN32_NT:
		{
			// Create a service entry table
			SERVICE_TABLE_ENTRY dispatchTable[] =
		    {
				{VNCSERVICENAME, (LPSERVICE_MAIN_FUNCTION)ServiceMain},
				{NULL, NULL}
			};

			// Call the service control dispatcher with our entry table
			if (!StartServiceCtrlDispatcher(dispatchTable))
				LogErrorMsg("StartServiceCtrlDispatcher failed.");
		}
		break;

	};

	return 0;
}

// SERVICE MAIN ROUTINE
void WINAPI ServiceMain(DWORD argc, char**argv)
{
	// Register the service control handler
    g_hstatus = RegisterServiceCtrlHandler(VNCSERVICENAME, ServiceCtrl);

    if (g_hstatus == 0)
		return;

	// Set up some standard service state values
    g_srvstatus.dwServiceType = SERVICE_WIN32 | SERVICE_INTERACTIVE_PROCESS;
    g_srvstatus.dwServiceSpecificExitCode = 0;

	// Give this status to the SCM
    if (!ReportStatus(
        SERVICE_START_PENDING,	// Service state
        NO_ERROR,				// Exit code type
        15000))					// Hint as to how long WinVNC should have hung before you assume error
	{
        ReportStatus(
			SERVICE_STOPPED,
			g_error,
            0);
		return;
	}

	// Now start the service for real
    omni_thread *workthread = omni_thread::create(ServiceWorkThread);
    return;
}

// SERVICE START ROUTINE - thread that calls WinVNCAppMain
void ServiceWorkThread(void *arg)
{
	// Save the current thread identifier
	g_servicethread = GetCurrentThreadId();

    // report the status to the service control manager.
    //
    if (!ReportStatus(
        SERVICE_RUNNING,       // service state
        NO_ERROR,              // exit code
        0))                    // wait hint
		return;

	// RUN!
	WinVNCAppMain();

	// Mark that we're no longer running
	g_servicethread = NULL;

	// Tell the service manager that we've stopped.
    ReportStatus(
		SERVICE_STOPPED,
		g_error,
		0);
}

// SERVICE STOP ROUTINE - post a quit message to the relevant thread
void ServiceStop()
{
	// Post a quit message to the main service thread
	if (g_servicethread != NULL)
	{
		vnclog.Print(LL_INTINFO, VNCLOG("quitting from ServiceStop\n"));
		PostThreadMessage(g_servicethread, WM_QUIT, 0, 0);
	}
}

// SERVICE INSTALL ROUTINE
int
vncService::ReinstallService() {
  RemoveService(1);
  InstallService(0);
  return 0;
}

int
vncService::InstallService(BOOL silent)
{
	const int pathlength = 2048;
	char path[pathlength];