/************************************************************************* Module: DeskSwitch.c Copyright (C) 1997-2000 by Microsoft Corporation. All rights reserved. *************************************************************************/ #ifdef _WIN32_IE #undef _WIN32_IE #endif #define _WIN32_IE 0x0600 #include // for IsOS #include // for IsOS //////////////////////////////////////////////////////////////////////////// // Helper functions and globals for detecting desktop switch // // Usage: Call InitWatchDeskSwitch() with an hWnd and message during // initialization. The message will be posted to hWnd whenever // a desktop switch has occurred. When the message is received // the desktop switch has taken place already. // // Call TermWatchDeskSwitch() to stop watching for desktop // switches. //////////////////////////////////////////////////////////////////////////// HANDLE g_hDesktopSwitchThread = 0; HANDLE g_hDesktopSwitchEvent = 0; HANDLE g_hTerminateEvent = 0; typedef struct MsgInfo { HWND hWnd; DWORD dwMsg; DWORD dwTIDMain; DWORD fPostMultiple; } MSG_INFO; MSG_INFO g_MsgInfo; void Cleanup() { if (g_hDesktopSwitchEvent) { CloseHandle(g_hDesktopSwitchEvent); g_hDesktopSwitchEvent = 0; } if (g_hTerminateEvent) { CloseHandle(g_hTerminateEvent); g_hTerminateEvent = 0; } } #ifndef DESKTOP_ACCESSDENIED #define DESKTOP_ACCESSDENIED 0 #define DESKTOP_DEFAULT 1 #define DESKTOP_SCREENSAVER 2 #define DESKTOP_WINLOGON 3 #define DESKTOP_TESTDISPLAY 4 #define DESKTOP_OTHER 5 #endif int GetDesktopType() { HDESK hdesk; TCHAR szName[100]; DWORD nl; int iCurrentDesktop = DESKTOP_OTHER; hdesk = OpenInputDesktop(0, FALSE, MAXIMUM_ALLOWED); if (!hdesk) { hdesk = OpenDesktop(TEXT("Winlogon"), 0, FALSE, MAXIMUM_ALLOWED); if (!hdesk) { // fails when ap has insufficient permission on secure desktop return DESKTOP_ACCESSDENIED; } } GetUserObjectInformation(hdesk, UOI_NAME, szName, 100, &nl); CloseDesktop(hdesk); if (!lstrcmpi(szName, TEXT("Default"))) { iCurrentDesktop = DESKTOP_DEFAULT; } else if (!lstrcmpi(szName, TEXT("Winlogon"))) { iCurrentDesktop = DESKTOP_WINLOGON; } return iCurrentDesktop; } // WatchDesktopProc - waits indefinitely for a desktop switch. When // it gets one, it posts a message to the window // specified in InitWatchDeskSwitch. It also waits // on an event that signals the procedure to exit. // DWORD WatchDesktopProc(LPVOID pvData) { BOOL fCont = TRUE; DWORD dwEventIndex; HANDLE ahEvents[2]; int iDesktopT, iCurrentDesktop = GetDesktopType(); SetThreadDesktop(GetThreadDesktop(g_MsgInfo.dwTIDMain)); ahEvents[0] = g_hDesktopSwitchEvent; ahEvents[1] = g_hTerminateEvent; while (fCont) { iDesktopT = GetDesktopType(); if (iDesktopT == iCurrentDesktop) { DBPRINTF(TEXT("Wait for desktop switch or exit on desktop = %d\r\n"), iCurrentDesktop); dwEventIndex = WaitForMultipleObjects(2, ahEvents, FALSE, INFINITE); dwEventIndex -= WAIT_OBJECT_0; } else { // missed a desktop switch so handle it dwEventIndex = 0; } switch (dwEventIndex) { case 0: // With a FUS there is a spurious switch to Winlogon iDesktopT = GetDesktopType(); DBPRINTF(TEXT("desktop switch from %d to %d\r\n"), iCurrentDesktop, iDesktopT); if (iDesktopT != iCurrentDesktop) { iCurrentDesktop = iDesktopT; // Handle desk switch event DBPRINTF(TEXT("WatchDesktopProc: PostMessage(0x%x, %d...) desktop %d\r\n"), g_MsgInfo.hWnd, g_MsgInfo.dwMsg, iCurrentDesktop); PostMessage(g_MsgInfo.hWnd, g_MsgInfo.dwMsg, iCurrentDesktop, 0); } else DBPRINTF(TEXT("WatchDesktopProc: Ignore switch to %d\r\n"), iDesktopT); break; case 1: // Handle terminate thread event fCont = FALSE; DBPRINTF(TEXT("WatchDesktopProc: got terminate event\r\n")); break; default: // Unexpected event fCont = FALSE; DBPRINTF(TEXT("WatchDesktopProc unexpected event %d\r\n"), dwEventIndex + WAIT_OBJECT_0); break; } } Cleanup(); DBPRINTF(TEXT("WatchDesktopProc returning...\r\n")); return 0; } // InitWatchDeskSwitch - starts a thread to watch for desktop switches // // hWnd [in] - window handle to post message to // dwMsg [in] - message to post on desktop switch // // Call this function after the window has been created whenever it // is to wait for a desktop switch. // void InitWatchDeskSwitch(HWND hWnd, DWORD dwMsg) { DWORD dwTID; if (g_hDesktopSwitchThread || g_hDesktopSwitchEvent) return; // don't do this again if it's already running // Create an unnamed event used to signal the thread to terminate g_hTerminateEvent = CreateEvent(NULL, FALSE, FALSE, NULL); // and open the desktop switch event. If utility manager is // running then we will wait on it's desktop switch event otherwise // wait on the system desktop switch event. If waiting on utilman // then only post one switch message. g_hDesktopSwitchEvent = OpenEvent(SYNCHRONIZE , FALSE , TEXT("UtilMan_DesktopSwitch")); g_MsgInfo.fPostMultiple = FALSE; if (!g_hDesktopSwitchEvent) { g_hDesktopSwitchEvent = OpenEvent(SYNCHRONIZE , FALSE , TEXT("WinSta0_DesktopSwitch")); g_MsgInfo.fPostMultiple = TRUE; } if (g_hDesktopSwitchEvent && g_hTerminateEvent) { g_MsgInfo.hWnd = hWnd; g_MsgInfo.dwMsg = dwMsg; g_MsgInfo.dwTIDMain = GetCurrentThreadId(); DBPRINTF(TEXT("InitWatchDeskSwitch(0x%x, %d, %d)\r\n"), g_MsgInfo.hWnd, g_MsgInfo.dwMsg, g_MsgInfo.dwTIDMain); g_hDesktopSwitchThread = CreateThread( NULL, 0 , WatchDesktopProc , &g_MsgInfo, 0 , &dwTID); } // cleanup if failed to create thread if (!g_hDesktopSwitchThread) { DBPRINTF(TEXT("InitWatchDeskSwitch failed!\r\n")); Cleanup(); } } // TermWatchDeskSwitch - cleans up after a desktop switch // // Call this function to terminate the thread that is watching // for desktop switches (if it is running) and to clean up the // event handle. // void TermWatchDeskSwitch() { DBPRINTF(TEXT("TermWatchDeskSwitch...\r\n")); if (g_hDesktopSwitchThread) { SetEvent(g_hTerminateEvent); DBPRINTF(TEXT("TermWatchDeskSwitch: SetEvent(0x%x)\r\n"), g_hDesktopSwitchThread); g_hDesktopSwitchThread = 0; } else DBPRINTF(TEXT("TermWatchDeskSwitch: g_hDesktopSwitchThread = 0\r\n")); } //////////////////////////////////////////////////////////////////////////// // helper functions for detecting if UtilMan is running (in // which case this applets is being managed by it) //////////////////////////////////////////////////////////////////////////// __inline BOOL IsUtilManRunning() { HANDLE hEvent = OpenEvent(SYNCHRONIZE, FALSE, TEXT("UtilityManagerIsActiveEvent")); if (hEvent != NULL) { CloseHandle(hEvent); return TRUE; } return FALSE; } __inline BOOL CanLockDesktopWithoutDisconnect() { // This function may have to change if UI is added to Whistler that // allows switching users for computers that are part of a domain. // For now, domain users may have FUS enabled because TS allows remote // logon which can result in multiple sessions on a machine (a form // of FUS) even though Start/Logoff doesn't allow the "Switch User" // option. In this case, the user can lock their desktop without // causing their session to disconnect. If FUS is explicitly off // in the registry then "Switch User" is not a Logoff option nor can // a remote logon happen and the user can lock their desktop without // causing their session to disconnect. return (IsOS(OS_DOMAINMEMBER) || !IsOS(OS_FASTUSERSWITCHING)); } //////////////////////////////////////////////////////////////////////////// // RunSecure - helper function to tell accessibility UI when to run secure // (no help, no active URL links, etc...). Accessibility UI // should run in secure mode if it is running on the winlogon // desktop or as SYSTEM. //////////////////////////////////////////////////////////////////////////// BOOL RunSecure(DWORD dwDesktop) { BOOL fOK = FALSE; BOOL fIsLocalSystem = FALSE; SID_IDENTIFIER_AUTHORITY siaLocalSystem = SECURITY_NT_AUTHORITY; PSID psidSystem = 0; if (dwDesktop == DESKTOP_WINLOGON) return TRUE; if (AllocateAndInitializeSid(&siaLocalSystem, 1, SECURITY_LOCAL_SYSTEM_RID, 0, 0, 0, 0, 0, 0, 0, &psidSystem) && psidSystem) { fOK = CheckTokenMembership(NULL, psidSystem, &fIsLocalSystem); FreeSid(psidSystem); } return (fOK && fIsLocalSystem); }