Restore SEBPatch

SafeExamBrowser.WindowsApi/ExplorerShell.cs

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 ETH Zürich, IT Services
+ * Copyright (c) 2025 ETH Zürich, IT Services
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -34,24 +34,106 @@ namespace SafeExamBrowser.WindowsApi
 		public void HideAllWindows()
 		{
 			logger.Info("Searching for windows to be minimized...");
+
+			foreach (var handle in nativeMethods.GetOpenWindows())
+			{
+				var window = new Window
+				{
+					Handle = handle,
+					Title = nativeMethods.GetWindowTitle(handle)
+				};
+
+				minimizedWindows.Add(window);
+				logger.Info($"Found window '{window.Title}' with handle = {window.Handle}.");
+			}
+
 			logger.Info("Minimizing all open windows...");
+			nativeMethods.MinimizeAllOpenWindows();
 			logger.Info("Open windows successfully minimized.");
 		}
 
 		public void RestoreAllWindows()
 		{
 			logger.Info("Restoring all minimized windows...");
+
+			foreach (var window in minimizedWindows)
+			{
+				nativeMethods.RestoreWindow(window.Handle);
+				logger.Info($"Restored window '{window.Title}' with handle = {window.Handle}.");
+			}
+
+			minimizedWindows.Clear();
 			logger.Info("Minimized windows successfully restored.");
 		}
 
 		public void Start()
 		{
+			var process = new System.Diagnostics.Process();
+			var explorerPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), "explorer.exe");
 
+			logger.Debug("Starting explorer shell process...");
+
+			process.StartInfo.CreateNoWindow = true;
+			process.StartInfo.FileName = explorerPath;
+			process.StartInfo.UseShellExecute = false;
+			process.StartInfo.WorkingDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Windows);
+			process.Start();
+
+			logger.Debug("Waiting for explorer shell to initialize...");
+
+			while (nativeMethods.GetShellWindowHandle() == IntPtr.Zero)
+			{
+				Thread.Sleep(20);
+			}
+
+			process.Refresh();
+			logger.Info($"Explorer shell successfully started with PID = {process.Id}.");
+			process.Close();
 		}
 
 		public void Terminate()
 		{
-			
+			const int THREE_SECONDS = 3000;
+			var processId = nativeMethods.GetShellProcessId();
+			var explorerProcesses = System.Diagnostics.Process.GetProcessesByName("explorer");
+			var process = explorerProcesses.FirstOrDefault(p => p.Id == processId);
+
+			if (process != null)
+			{
+				logger.Debug($"Found explorer shell processes with PID = {processId}. Sending close message...");
+				nativeMethods.PostCloseMessageToShell();
+				logger.Debug("Waiting for explorer shell to terminate...");
+
+				for (var elapsed = 0; nativeMethods.GetShellWindowHandle() != IntPtr.Zero && elapsed < THREE_SECONDS; elapsed += 20)
+				{
+					Thread.Sleep(20);
+				}
+
+				process.WaitForExit(THREE_SECONDS);
+				process.Refresh();
+
+				if (!process.HasExited)
+				{
+					KillExplorerShell(process.Id);
+				}
+
+				process.Refresh();
+
+				if (process.HasExited)
+				{
+					logger.Info($"Successfully terminated explorer shell process with PID = {processId}.");
+				}
+				else
+				{
+					logger.Error($"Failed to completely terminate explorer shell process with PID = {processId}.");
+				}
+
+				process.Close();
+			}
+			else
+			{
+				logger.Info("The explorer shell seems to already be terminated.");
+			}
 		}
 
 		private void KillExplorerShell(int processId)