Allow multiple instances of MTA/GTA

Author: botder

Client/core/CCore.cpp

@@ -834,12 +834,27 @@ void CCore::ApplyHooks()
 
     // Create our hooks.
     m_pDirectInputHookManager->ApplyHook();
-    // m_pDirect3DHookManager->ApplyHook ( );
     m_pSetCursorPosHook->ApplyHook();
 
     // Remove useless DirectPlay dependency (dpnhpast.dll) @ 0x745701
     // We have to patch here as multiplayer_sa and game_sa are loaded too late
     DetourLibraryFunction("kernel32.dll", "LoadLibraryA", Win32LoadLibraryA, SkipDirectPlay_LoadLibraryA);
+
+    // Disable code that disallows multiple instances of GTA:SA
+    // Disable `if (IsAppAlreadyRunning())` in WinMain
+    {
+        DWORD oldProtect;
+        VirtualProtect(reinterpret_cast<void*>(0x74872D), 9, PAGE_READWRITE, &oldProtect);
+        memcpy(reinterpret_cast<void*>(0x74872D), "\x90\x90\x90\x90\x90\x90\x90\x90\x90", 9);
+        VirtualProtect(reinterpret_cast<void*>(0x74872D), 9, oldProtect, &oldProtect);
+    }
+    // Create an unnamed semaphore in CdStreamInitThread.
+    {
+        DWORD oldProtect;
+        VirtualProtect(reinterpret_cast<void*>(0x406945), 5, PAGE_READWRITE, &oldProtect);
+        memcpy(reinterpret_cast<void*>(0x406945), "\x6A\x00\x90\x90\x90", 5);
+        VirtualProtect(reinterpret_cast<void*>(0x406945), 5, oldProtect, &oldProtect);
+    }
 }
 
 bool UsingAltD3DSetup()

Client/loader/CInstallManager.cpp

@@ -361,17 +361,14 @@ SString CInstallManager::_ChangeToAdmin()
             NULL, SString(_("MTA:SA needs Administrator access for the following task:\n\n  '%s'\n\nPlease confirm in the next window."), *m_strAdminReason),
             "Multi Theft Auto: San Andreas", MB_OK | MB_ICONINFORMATION | MB_TOPMOST);
         SetIsBlockingUserProcess();
-        ReleaseSingleInstanceMutex();
         if (ShellExecuteBlocking("runas", GetLauncherPathFilename(), GetSequencerSnapshot()))
         {
             // Will return here once admin process has finished
-            CreateSingleInstanceMutex();
             UpdateSettingsForReportLog();
             RestoreSequencerFromSnapshot(ReceiveStringFromAdminProcess());
             ClearIsBlockingUserProcess();
             return "ok";            // This will appear as the result for _ChangeFromAdmin
         }
-        CreateSingleInstanceMutex();
         ClearIsBlockingUserProcess();
         MessageBoxUTF8(NULL, SString(_("MTA:SA could not complete the following task:\n\n  '%s'\n"), *m_strAdminReason),
                        "Multi Theft Auto: San Andreas" + _E("CL01"), MB_OK | MB_ICONWARNING | MB_TOPMOST);
@@ -478,10 +475,9 @@ SString CInstallManager::_MaybeSwitchToTempExe()
     // If a new "Multi Theft Auto.exe" exists, let that complete the install
     if (m_pSequencer->GetVariable(INSTALL_LOCATION) == "far")
     {
-        ReleaseSingleInstanceMutex();
         if (ShellExecuteNonBlocking("open", GetLauncherPathFilename(), GetSequencerSnapshot()))
             ExitProcess(0);            // All done here
-        CreateSingleInstanceMutex();
+
         return "fail";
     }
     return "ok";
@@ -501,10 +497,9 @@ SString CInstallManager::_SwitchBackFromTempExe()
     {
         m_pSequencer->SetVariable(INSTALL_LOCATION, "near");
 
-        ReleaseSingleInstanceMutex();
         if (ShellExecuteNonBlocking("open", GetLauncherPathFilename(), GetSequencerSnapshot()))
             ExitProcess(0);            // All done here
-        CreateSingleInstanceMutex();
+
         return "fail";
     }
     return "ok";
@@ -584,9 +579,6 @@ SString CInstallManager::_PrepareLaunchLocation()
 {
     const bool isAdmin = IsUserAdmin();
 
-    // Ensure GTA exe is not running
-    TerminateGTAIfRunning();
-
     const fs::path gtaDir = GetGameBaseDirectory();
     const fs::path mtaDir = GetMTARootDirectory() / "MTA";
     const fs::path launchDir = GetGameLaunchDirectory();
@@ -718,9 +710,6 @@ SString CInstallManager::_ProcessGtaPatchCheck()
 //////////////////////////////////////////////////////////
 SString CInstallManager::_ProcessGtaDllCheck()
 {
-    // Ensure GTA exe is not running
-    TerminateGTAIfRunning();
-
     struct DependencyHash
     {
         const char* fileName;

Client/loader/Main.cpp

@@ -93,9 +93,6 @@ MTAEXPORT int DoWinMain(HINSTANCE hLauncherInstance, HINSTANCE hPrevInstance, LP
     BsodDetectionPreLaunch();
     MaybeShowCopySettingsDialog();
 
-    // Make sure GTA is not running
-    HandleIfGTAIsAlreadyRunning();
-
     // Maybe warn user if no anti-virus running
     CheckAntiVirusStatus();
 

Client/loader/MainFunctions.cpp

@@ -200,81 +200,38 @@ void HandleSpecialLaunchOptions()
 //////////////////////////////////////////////////////////
 void HandleDuplicateLaunching()
 {
-    LPSTR lpCmdLine = GetCommandLine();
+    LPWSTR szCommandLine = GetCommandLineW();
 
-    int iRecheckTimeLimit = 2000;
-    while (!CreateSingleInstanceMutex())
-    {
-        if (strcmp(lpCmdLine, "") != 0)
-        {
-            HWND hwMTAWindow = FindWindow(NULL, "MTA: San Andreas");
+    if (!szCommandLine[0])
+        return;
+
+    HWND gameWindow = FindWindowA(nullptr, "MTA: San Andreas");
 #ifdef MTA_DEBUG
-            if (hwMTAWindow == NULL)
-                hwMTAWindow = FindWindow(NULL, "MTA: San Andreas [DEBUG]");
+    if (gameWindow == nullptr)
+        gameWindow = FindWindowA(nullptr, "MTA: San Andreas [DEBUG]");
 #endif
-            if (hwMTAWindow != NULL)
-            {
-                LPWSTR  szCommandLine = GetCommandLineW();
-                int     numArgs;
-                LPWSTR* aCommandLineArgs = CommandLineToArgvW(szCommandLine, &numArgs);
-                for (int i = 1; i < numArgs; ++i)
-                {
-                    if (WStringX(aCommandLineArgs[i]).BeginsWith(L"mtasa://"))
-                    {
-                        WString wideConnectInfo = aCommandLineArgs[i];
-                        SString strConnectInfo = ToUTF8(wideConnectInfo);
 
-                        COPYDATASTRUCT cdStruct;
-                        cdStruct.cbData = strConnectInfo.length() + 1;
-                        cdStruct.lpData = const_cast<char*>(strConnectInfo.c_str());
-                        cdStruct.dwData = URI_CONNECT;
+    if (gameWindow == nullptr)
+        return;
 
-                        SendMessage(hwMTAWindow, WM_COPYDATA, NULL, (LPARAM)&cdStruct);
-                        break;
-                    }
-                }
-            }
-            else
-            {
-                if (iRecheckTimeLimit > 0)
-                {
-                    // Sleep a little bit and check the mutex again
-                    Sleep(500);
-                    iRecheckTimeLimit -= 500;
-                    continue;
-                }
-                SString strMessage;
-                strMessage +=
-                    _("Trouble restarting MTA:SA\n\n"
-                      "If the problem persists, open Task Manager and\n"
-                      "stop the 'gta_sa.exe' and 'Multi Theft Auto.exe' processes\n\n\n"
-                      "Try to launch MTA:SA again?");
-                if (MessageBoxUTF8(0, strMessage, _("Error") + _E("CL04"), MB_ICONWARNING | MB_YESNO | MB_TOPMOST) ==
-                    IDYES)            // Trouble restarting MTA:SA
-                {
-                    TerminateGTAIfRunning();
-                    TerminateOtherMTAIfRunning();
-                    ShellExecuteNonBlocking("open", PathJoin(GetMTASAPath(), MTA_EXE_NAME), lpCmdLine);
-                }
-                return ExitProcess(EXIT_ERROR);
-            }
-        }
-        else
+    int     numArgs;
+    LPWSTR* aCommandLineArgs = CommandLineToArgvW(szCommandLine, &numArgs);
+
+    for (int i = 1; i < numArgs; ++i)
+    {
+        if (WStringX(aCommandLineArgs[i]).BeginsWith(L"mtasa://"))
         {
-            if (!IsGTARunning() && !IsOtherMTARunning())
-            {
-                MessageBoxUTF8(0, _("Another instance of MTA is already running.\n\nIf this problem persists, please restart your computer"),
-                               _("Error") + _E("CL05"), MB_ICONERROR | MB_TOPMOST);
-            }
-            else if (MessageBoxUTF8(0, _("Another instance of MTA is already running.\n\nDo you want to terminate it?"), _("Error") + _E("CL06"),
-                                    MB_ICONQUESTION | MB_YESNO | MB_TOPMOST) == IDYES)
-            {
-                TerminateGTAIfRunning();
-                TerminateOtherMTAIfRunning();
-                ShellExecuteNonBlocking("open", PathJoin(GetMTASAPath(), MTA_EXE_NAME), lpCmdLine);
-            }
+            WString wideConnectInfo = aCommandLineArgs[i];
+            SString strConnectInfo = ToUTF8(wideConnectInfo);
+
+            COPYDATASTRUCT cdStruct;
+            cdStruct.cbData = strConnectInfo.length() + 1;
+            cdStruct.lpData = const_cast<char*>(strConnectInfo.c_str());
+            cdStruct.dwData = URI_CONNECT;
+
+            SendMessage(gameWindow, WM_COPYDATA, NULL, (LPARAM)&cdStruct);
+            return ExitProcess(EXIT_ERROR);
         }
-        return ExitProcess(EXIT_ERROR);
     }
 }
 
@@ -480,8 +437,6 @@ void HandleCustomStartMessage()
 //////////////////////////////////////////////////////////
 void PreLaunchWatchDogs()
 {
-    assert(!CreateSingleInstanceMutex());
-
     //
     // "L0" is opened before the launch sequence and is closed if MTA shutsdown with no error
     // "L1" is opened before the launch sequence and is closed if GTA is succesfully started
@@ -587,35 +542,6 @@ void PostRunWatchDogs(int iReturnCode)
     }
 }
 
-//////////////////////////////////////////////////////////
-//
-// HandleIfGTAIsAlreadyRunning
-//
-// Check for and maybe stop a running GTA process
-//
-//////////////////////////////////////////////////////////
-void HandleIfGTAIsAlreadyRunning()
-{
-    if (IsGTARunning())
-    {
-        if (MessageBoxUTF8(
-                0, _("An instance of GTA: San Andreas is already running. It needs to be terminated before MTA:SA can be started. Do you want to do that now?"),
-                _("Information") + _E("CL10"), MB_YESNO | MB_ICONQUESTION | MB_TOPMOST) == IDYES)
-        {
-            TerminateOtherMTAIfRunning();
-            TerminateGTAIfRunning();
-            if (IsGTARunning())
-            {
-                MessageBoxUTF8(0, _("Unable to terminate GTA: San Andreas. If the problem persists, please restart your computer."),
-                               _("Information") + _E("CL11"), MB_OK | MB_ICONERROR | MB_TOPMOST);
-                return ExitProcess(EXIT_ERROR);
-            }
-        }
-        else
-            return ExitProcess(EXIT_OK);
-    }
-}
-
 //////////////////////////////////////////////////////////
 //
 // ValidateGTAPath
@@ -844,7 +770,6 @@ void CheckDataFiles()
     {
         SString strMessage(_("Main file has an incorrect name (%s)"), *GetLaunchFilename());
         int     iResponse = MessageBoxUTF8(NULL, strMessage, _("Error") + _E("CL33"), MB_RETRYCANCEL | MB_ICONERROR | MB_TOPMOST);
-        ReleaseSingleInstanceMutex();
         if (iResponse == IDRETRY)
             ShellExecuteNonBlocking("open", PathJoin(strMTASAPath, MTA_EXE_NAME));
         return ExitProcess(EXIT_ERROR);
@@ -1272,7 +1197,6 @@ int LaunchGame(SString strCmdLine)
     //
     // Cleanup and exit.
     CloseHandle(piLoadee.hProcess);
-    ReleaseSingleInstanceMutex();
 
     // Success, maybe
     return dwExitCode;

Client/loader/MainFunctions.h

@@ -16,7 +16,6 @@ void HandleDuplicateLaunching();
 void HandleCustomStartMessage();
 void PreLaunchWatchDogs();
 void PostRunWatchDogs(int iReturnCode);
-void HandleIfGTAIsAlreadyRunning();
 void ValidateGTAPath();
 void CheckAntiVirusStatus();
 void CheckDataFiles();