Fixes for shell extension

* Properly implemented cleanup routines when injected into
applications other than Explorer
* Never EVER forget to specify a ThreadingModel for a COM object
in registry. That was the cause the DLL was making Microsoft Teams
crash on startup
* Do not free memory when the DLL is unloaded (DLL_PROCESS_DETACH)
and lpvReserved is non-NULL. It means the DLL is unloaded as the process
terminates, in which case all threads are dead, so it is not safe to call freeing
routines - let the operating system reclaim the memory on process exit

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 This document includes the same release notes as in the [Releases](https://github.com/valinet/ExplorerPatcher/releases) section on GitHub.
 
+## 22000.318.36
+
+Tested on build 22000.318.
+
+#### Fixes
+
+* Lots of bug and issue fixes for shell extension failing to work under certain circumstances; fixed #259
+
 ## 22000.318.35
 
 Tested on build 22000.318.

ExplorerPatcher/ExplorerPatcher.rc

@@ -51,8 +51,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 22000,318,35,0
+ FILEVERSION 22000,318,36,0
- PRODUCTVERSION 22000,318,35,0
+ PRODUCTVERSION 22000,318,36,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -69,12 +69,12 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "VALINET Solutions SRL"
             VALUE "FileDescription", "ExplorerPatcher"
-            VALUE "FileVersion", "22000.318.35.0"
+            VALUE "FileVersion", "22000.318.36.0"
             VALUE "InternalName", "ExplorerPatcher.dll"
             VALUE "LegalCopyright", "Copyright (C) 2006-2021 VALINET Solutions SRL. All rights reserved."
             VALUE "OriginalFilename", "ExplorerPatcher.dll"
             VALUE "ProductName", "ExplorerPatcher"
-            VALUE "ProductVersion", "22000.318.35.0"
+            VALUE "ProductVersion", "22000.318.36.0"
         END
     END
     BLOCK "VarFileInfo"

ExplorerPatcher/SettingsMonitor.c

@@ -3,83 +3,113 @@
 DWORD WINAPI MonitorSettings(SettingsChangeParameters* params)
 {
 	BOOL bShouldExit = FALSE;
+	HANDLE* handles = NULL;
+	printf("[SettingsMonitor] Started %p\n", params->settings[0].hEvent);
 
 	while (TRUE)
 	{
-		HANDLE* handles = malloc(sizeof(HANDLE) * (params->size + 1));
+		handles = calloc(sizeof(HANDLE), params->size);
-		if (!handles)
+		if (handles)
 		{
-			return 0;
+			for (unsigned int i = 0; i < params->size; ++i)
-		}
-		for (unsigned int i = 0; i < params->size; ++i)
-		{
-			params->settings[i].hEvent = CreateEventW(NULL, FALSE, FALSE, NULL);
-			if (!params->settings[i].hEvent)
-			{
-				return 0;
-			}
-			handles[i] = params->settings[i].hEvent;
-			if (RegCreateKeyExW(
-				params->settings[i].origin,
-				params->settings[i].name,
-				0,
-				NULL,
-				REG_OPTION_NON_VOLATILE,
-				KEY_READ,
-				NULL,
-				&(params->settings[i].hKey),
-				NULL
-			) != ERROR_SUCCESS)
 			{
-				return 0;
+				if (i == 0)
+				{
+					if (params->settings[i].hEvent)
+					{
+						handles[i] = params->settings[i].hEvent;
+						continue;
+					}
+					else
+					{
+						InterlockedExchange(&(params->size), NULL);
+						return 0;
+					}
+				}
+				params->settings[i].hEvent = CreateEventW(NULL, FALSE, FALSE, NULL);
+				if (!params->settings[i].hEvent)
+				{
+					InterlockedExchange(&(params->size), 0);
+					return 0;
+				}
+				handles[i] = params->settings[i].hEvent;
+				if (RegCreateKeyExW(
+					params->settings[i].origin,
+					params->settings[i].name,
+					0,
+					NULL,
+					REG_OPTION_NON_VOLATILE,
+					KEY_READ,
+					NULL,
+					&(params->settings[i].hKey),
+					NULL
+				) != ERROR_SUCCESS)
+				{
+					InterlockedExchange(&(params->size), 0);
+					return 0;
+				}
+				if (RegNotifyChangeKeyValue(
+					params->settings[i].hKey,
+					FALSE,
+					REG_NOTIFY_CHANGE_LAST_SET,
+					params->settings[i].hEvent,
+					TRUE
+				) != ERROR_SUCCESS)
+				{
+					InterlockedExchange(&(params->size), 0);
+					return 0;
+				}
 			}
-			if (RegNotifyChangeKeyValue(
+			DWORD dwRes = WaitForMultipleObjects(
-				params->settings[i].hKey,
+				params->size,
+				handles,
 				FALSE,
-				REG_NOTIFY_CHANGE_LAST_SET,
+				INFINITE
-				params->settings[i].hEvent,
+			);
-				TRUE
+			if (dwRes != WAIT_FAILED)
-			) != ERROR_SUCCESS)
-			{
-				return 0;
-			}
-		}
-		handles[params->size] = params->hExitEvent;
-		DWORD dwRes = WaitForMultipleObjects(
-			params->size + (params->hExitEvent ? 1 : 0),
-			handles,
-			FALSE,
-			INFINITE
-		);
-		if (dwRes != WAIT_FAILED)
-		{
-			unsigned int i = dwRes - WAIT_OBJECT_0;
-			if (i >= 0 && i < params->size)
-			{
-				params->settings[i].callback(params->settings[i].data);
-			}
-			else if (i == params->size && params->hExitEvent)
 			{
-				bShouldExit = TRUE;
+				unsigned int i = dwRes - WAIT_OBJECT_0;
+				if (i >= 1 && i < params->size)
+				{
+					params->settings[i].callback(params->settings[i].data);
+				}
+				else if (i == 0)
+				{
+					bShouldExit = TRUE;
+				}
+				for (unsigned int j = 1; j < params->size; ++j)
+				{
+					if (WaitForSingleObject(handles[j], 0) == WAIT_OBJECT_0)
+					{
+						params->settings[j].callback(params->settings[j].data);
+					}
+				}
 			}
-			for (unsigned int j = 0; j < params->size; ++j)
+			free(handles);
+			for (unsigned int i = 1; i < params->size; ++i)
 			{
-				if (WaitForSingleObject(handles[j], 0) == WAIT_OBJECT_0)
+				if (params->settings[i].hEvent)
+				{
+					CloseHandle(params->settings[i].hEvent);
+				}
+				if (params->settings[i].hKey)
 				{
-					params->settings[j].callback(params->settings[j].data);
+					RegCloseKey(params->settings[i].hKey);
 				}
 			}
+			if (bShouldExit)
+			{
+				break;
+			}
 		}
-		free(handles);
+		else
-		for (unsigned int i = 0; i < params->size; ++i)
-		{
-			CloseHandle(params->settings[i].hEvent);
-			RegCloseKey(params->settings[i].hKey);
-		}
-		if (bShouldExit)
 		{
-			break;
+			InterlockedExchange(&(params->size), 0);
+			return 0;
 		}
 	}
+	printf("[SettingsMonitor] Ended %p\n", params->settings[0].hEvent);
+	InterlockedExchange(&(params->size), 0);
+	return 0;
 }
 

ExplorerPatcher/SettingsMonitor.h

@@ -3,6 +3,7 @@
 #include <Windows.h>
 #include <Shlwapi.h>
 #pragma comment(lib, "Shlwapi.lib")
+#include <stdio.h>
 
 typedef struct _Setting
 {
@@ -17,7 +18,7 @@ typedef struct _SettingsChangeParameters
 {
     Setting* settings;
     DWORD size;
-    HANDLE hExitEvent;
+    HANDLE hThread;
 } SettingsChangeParameters;
 DWORD WINAPI MonitorSettings(SettingsChangeParameters*);
 #endif

ExplorerPatcher/dllmain.c

@@ -70,11 +70,9 @@ DWORD bTaskbarMonitorOverride = 0;
 DWORD dwIMEStyle = 0;
 DWORD dwTaskbarAl = 0;
 HMODULE hModule = NULL;
-HANDLE hSettingsMonitorThread = NULL;
 HANDLE hDelayedInjectionThread = NULL;
 HANDLE hIsWinXShown = NULL;
 HANDLE hWinXThread = NULL;
-HANDLE hExitSettingsMonitor = NULL;
 HANDLE hSwsSettingsChanged = NULL;
 HANDLE hSwsOpacityMaybeChanged = NULL;
 BYTE* lpShouldDisplayCCButton = NULL;
@@ -3948,92 +3946,159 @@ __declspec(dllexport) DWORD WINAPI main(
         hSwsOpacityMaybeChanged = CreateEventW(NULL, FALSE, FALSE, NULL);
     }
 
-    settings = calloc(10, sizeof(Setting));
+    if (!settings && !settingsParams)
-    settings[0].callback = LoadSettings;
+    {
-    settings[0].data = bIsExplorer;
+        unsigned int numSettings = bIsExplorer ? 11 : 2;
-    settings[0].hEvent = NULL;
+        settings = calloc(numSettings, sizeof(Setting));
-    settings[0].hKey = NULL;
+        if (settings)
-    wcscpy_s(settings[0].name, MAX_PATH, TEXT(REGPATH));
+        {
-    settings[0].origin = HKEY_CURRENT_USER;
+            unsigned int cs = 0;
-
+
-    settings[1].callback = LoadSettings;
+            if (cs < numSettings)
-    settings[1].data = bIsExplorer;
+            {
-    settings[1].hEvent = NULL;
+                settings[cs].callback = NULL;
-    settings[1].hKey = NULL;
+                settings[cs].data = NULL;
-    wcscpy_s(settings[1].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\StartPage");
+                settings[cs].hEvent = CreateEventW(NULL, FALSE, FALSE, NULL);
-    settings[1].origin = HKEY_CURRENT_USER;
+                settings[cs].hKey = NULL;
-
+                ZeroMemory(settings[cs].name, MAX_PATH);
-    settings[2].callback = SetEvent;
+                settings[cs].origin = NULL;
-    settings[2].data = hSwsSettingsChanged;
+                cs++;
-    settings[2].hEvent = NULL;
+            }
-    settings[2].hKey = NULL;
+
-    wcscpy_s(settings[2].name, MAX_PATH, TEXT(REGPATH) L"\\sws");
+            if (cs < numSettings)
-    settings[2].origin = HKEY_CURRENT_USER;
+            {
-
+                settings[cs].callback = LoadSettings;
-    settings[3].callback = SetEvent;
+                settings[cs].data = bIsExplorer;
-    settings[3].data = hSwsOpacityMaybeChanged;
+                settings[cs].hEvent = NULL;
-    settings[3].hEvent = NULL;
+                settings[cs].hKey = NULL;
-    settings[3].hKey = NULL;
+                wcscpy_s(settings[cs].name, MAX_PATH, TEXT(REGPATH));
-    wcscpy_s(settings[3].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\MultitaskingView\\AltTabViewHost");
+                settings[cs].origin = HKEY_CURRENT_USER;
-    settings[3].origin = HKEY_CURRENT_USER;
+                cs++;
-
+            }
-    settings[4].callback = Explorer_RefreshUI;
+
-    settings[4].data = NULL;
+            if (cs < numSettings)
-    settings[4].hEvent = NULL;
+            {
-    settings[4].hKey = NULL;
+                settings[cs].callback = LoadSettings;
-    wcscpy_s(settings[4].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced");
+                settings[cs].data = bIsExplorer;
-    settings[4].origin = HKEY_CURRENT_USER;
+                settings[cs].hEvent = NULL;
-
+                settings[cs].hKey = NULL;
-    settings[5].callback = Explorer_RefreshUI;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\StartPage");
-    settings[5].data = NULL;
+                settings[cs].origin = HKEY_CURRENT_USER;
-    settings[5].hEvent = NULL;
+                cs++;
-    settings[5].hKey = NULL;
+            }
-    wcscpy_s(settings[5].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Search");
+
-    settings[5].origin = HKEY_CURRENT_USER;
+            if (cs < numSettings)
-
+            {
-    settings[6].callback = Explorer_RefreshUI;
+                settings[cs].callback = SetEvent;
-    settings[6].data = NULL;
+                settings[cs].data = hSwsSettingsChanged;
-    settings[6].hEvent = NULL;
+                settings[cs].hEvent = NULL;
-    settings[6].hKey = NULL;
+                settings[cs].hKey = NULL;
-    wcscpy_s(settings[6].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced\\People");
+                wcscpy_s(settings[cs].name, MAX_PATH, TEXT(REGPATH) L"\\sws");
-    settings[6].origin = HKEY_CURRENT_USER;
+                settings[cs].origin = HKEY_CURRENT_USER;
-
+                cs++;
-    settings[7].callback = Explorer_RefreshUI;
+            }
-    settings[7].data = NULL;
+
-    settings[7].hEvent = NULL;
+            if (cs < numSettings)
-    settings[7].hKey = NULL;
+            {
-    wcscpy_s(settings[7].name, MAX_PATH, L"SOFTWARE\\Microsoft\\TabletTip\\1.7");
+                settings[cs].callback = SetEvent;
-    settings[7].origin = HKEY_CURRENT_USER;
+                settings[cs].data = hSwsOpacityMaybeChanged;
-
+                settings[cs].hEvent = NULL;
-    settings[8].callback = SetEvent;
+                settings[cs].hKey = NULL;
-    settings[8].data = hSwsSettingsChanged;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\MultitaskingView\\AltTabViewHost");
-    settings[8].hEvent = NULL;
+                settings[cs].origin = HKEY_CURRENT_USER;
-    settings[8].hKey = NULL;
+                cs++;
-    wcscpy_s(settings[8].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer");
+            }
-    settings[8].origin = HKEY_CURRENT_USER;
+
-
+            if (cs < numSettings)
-    settings[9].callback = UpdateStartMenuPositioning;
+            {
-    settings[9].data = MAKELPARAM(FALSE, TRUE);
+                settings[cs].callback = Explorer_RefreshUI;
-    settings[9].hEvent = NULL;
+                settings[cs].data = NULL;
-    settings[9].hKey = NULL;
+                settings[cs].hEvent = NULL;
-    wcscpy_s(settings[9].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced");
+                settings[cs].hKey = NULL;
-    settings[9].origin = HKEY_CURRENT_USER;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced");
-
+                settings[cs].origin = HKEY_CURRENT_USER;
-    settingsParams = calloc(1, sizeof(SettingsChangeParameters));
+                cs++;
-    settingsParams->settings = settings;
+            }
-    settingsParams->size = bIsExplorer ? 10 : 1;
+
-    hExitSettingsMonitor = CreateEventW(NULL, FALSE, FALSE, NULL);
+            if (cs < numSettings)
-    settingsParams->hExitEvent = hExitSettingsMonitor;
+            {
-    if (!hSettingsMonitorThread)
+                settings[cs].callback = Explorer_RefreshUI;
-    {
+                settings[cs].data = NULL;
-        hSettingsMonitorThread = CreateThread(
+                settings[cs].hEvent = NULL;
-            0,
+                settings[cs].hKey = NULL;
-            0,
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Search");
-            MonitorSettings,
+                settings[cs].origin = HKEY_CURRENT_USER;
-            settingsParams,
+                cs++;
-            0,
+            }
-            0
+
-        );
+            if (cs < numSettings)
+            {
+                settings[cs].callback = Explorer_RefreshUI;
+                settings[cs].data = NULL;
+                settings[cs].hEvent = NULL;
+                settings[cs].hKey = NULL;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced\\People");
+                settings[cs].origin = HKEY_CURRENT_USER;
+                cs++;
+            }
+
+            if (cs < numSettings)
+            {
+                settings[cs].callback = Explorer_RefreshUI;
+                settings[cs].data = NULL;
+                settings[cs].hEvent = NULL;
+                settings[cs].hKey = NULL;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\TabletTip\\1.7");
+                settings[cs].origin = HKEY_CURRENT_USER;
+                cs++;
+            }
+
+            if (cs < numSettings)
+            {
+                settings[cs].callback = SetEvent;
+                settings[cs].data = hSwsSettingsChanged;
+                settings[cs].hEvent = NULL;
+                settings[cs].hKey = NULL;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer");
+                settings[cs].origin = HKEY_CURRENT_USER;
+                cs++;
+            }
+
+            if (cs < numSettings)
+            {
+                settings[cs].callback = UpdateStartMenuPositioning;
+                settings[cs].data = MAKELPARAM(FALSE, TRUE);
+                settings[cs].hEvent = NULL;
+                settings[cs].hKey = NULL;
+                wcscpy_s(settings[cs].name, MAX_PATH, L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Advanced");
+                settings[cs].origin = HKEY_CURRENT_USER;
+                cs++;
+            }
+
+            settingsParams = calloc(1, sizeof(SettingsChangeParameters));
+            if (settingsParams)
+            {
+                settingsParams->settings = settings;
+                InterlockedExchange(&(settingsParams->size), numSettings);
+                settingsParams->hThread = CreateThread(
+                    0,
+                    0,
+                    MonitorSettings,
+                    settingsParams,
+                    0,
+                    0
+                );
+            }
+            else
+            {
+                if (numSettings && settings[0].hEvent)
+                {
+                    CloseHandle(settings[0].hEvent);
+                }
+                free(settings);
+                settings = NULL;
+            }
+        }
     } 
 
     InjectBasicFunctions(bIsExplorer, TRUE);
@@ -4699,6 +4764,14 @@ HRESULT WINAPI _DllRegisterServer()
                 wszFilename,
                 (wcslen(wszFilename) + 1) * sizeof(wchar_t)
             );
+            dwLastError = RegSetValueExW(
+                hKey,
+                L"ThreadingModel",
+                0,
+                REG_SZ,
+                L"Apartment",
+                10 * sizeof(wchar_t)
+            );
             RegCloseKey(hKey);
         }
     }
@@ -4735,6 +4808,14 @@ HRESULT WINAPI _DllRegisterServer()
                 wszFilename,
                 (wcslen(wszFilename) + 1) * sizeof(wchar_t)
             );
+            dwLastError = RegSetValueExW(
+                hKey,
+                L"ThreadingModel",
+                0,
+                REG_SZ,
+                L"Apartment",
+                10 * sizeof(wchar_t)
+            );
             RegCloseKey(hKey);
         }
     }
@@ -5213,6 +5294,25 @@ BOOL WINAPI DllMain(
     case DLL_THREAD_DETACH:
         break;
     case DLL_PROCESS_DETACH:
+        if (!lpvReserved && bInstanced)
+        {
+            if (settings && settingsParams)
+            {
+                SetEvent(settings[0].hEvent);
+                if (WaitForSingleObject(settingsParams->hThread, 0) != WAIT_OBJECT_0)
+                {
+                    while (InterlockedCompareExchange(&(settingsParams->size), 0, 0)) {};
+                }
+                CloseHandle(settings[0].hEvent);
+                CloseHandle(settingsParams->hThread);
+                free(settingsParams);
+                settingsParams = NULL;
+                free(settings);
+                settings = NULL;
+            }
+            InjectBasicFunctions(FALSE, FALSE);
+            bInstanced = FALSE;
+        }
         break;
     }
     return TRUE;