SEBWIN-313: Finished blacklist monitoring.

SafeExamBrowser.Client/ClientController.cs

@@ -7,6 +7,7 @@
  */
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using SafeExamBrowser.Browser.Contracts;
@@ -170,6 +171,7 @@ namespace SafeExamBrowser.Client
 		{
 			actionCenter.QuitButtonClicked += Shell_QuitButtonClicked;
 			applicationMonitor.ExplorerStarted += ApplicationMonitor_ExplorerStarted;
+			applicationMonitor.TerminationFailed += ApplicationMonitor_TerminationFailed;
 			Browser.ConfigurationDownloadRequested += Browser_ConfigurationDownloadRequested;
 			ClientHost.MessageBoxRequested += ClientHost_MessageBoxRequested;
 			ClientHost.PasswordRequested += ClientHost_PasswordRequested;
@@ -185,6 +187,7 @@ namespace SafeExamBrowser.Client
 		{
 			actionCenter.QuitButtonClicked -= Shell_QuitButtonClicked;
 			applicationMonitor.ExplorerStarted -= ApplicationMonitor_ExplorerStarted;
+			applicationMonitor.TerminationFailed -= ApplicationMonitor_TerminationFailed;
 			displayMonitor.DisplayChanged -= DisplayMonitor_DisplaySettingsChanged;
 			runtime.ConnectionLost -= Runtime_ConnectionLost;
 			taskbar.QuitButtonClicked -= Shell_QuitButtonClicked;
@@ -230,6 +233,13 @@ namespace SafeExamBrowser.Client
 			logger.Info("Desktop successfully restored.");
 		}
 
+		private void ApplicationMonitor_TerminationFailed(IEnumerable<RunningApplication> applications)
+		{
+			// foreach actionCenterActivator -> Pause
+			// TODO: Show lock screen!
+			// foreach actionCenterActivator -> Resume
+		}
+
 		private void Browser_ConfigurationDownloadRequested(string fileName, DownloadEventArgs args)
 		{
 			if (Settings.ConfigurationMode == ConfigurationMode.ConfigureClient)

SafeExamBrowser.Client/CompositionRoot.cs

@@ -52,6 +52,7 @@ namespace SafeExamBrowser.Client
 {
 	internal class CompositionRoot
 	{
+		private const int TWO_SECONDS = 2000;
 		private const int FIVE_SECONDS = 5000;
 
 		private Guid authenticationToken;
@@ -94,7 +95,7 @@ namespace SafeExamBrowser.Client
 			taskbar = BuildTaskbar();
 			terminationActivator = new TerminationActivator(ModuleLogger(nameof(TerminationActivator)));
 
-			var applicationMonitor = new ApplicationMonitor(FIVE_SECONDS, ModuleLogger(nameof(ApplicationMonitor)), nativeMethods, new ProcessFactory(ModuleLogger(nameof(ProcessFactory))));
+			var applicationMonitor = new ApplicationMonitor(TWO_SECONDS, ModuleLogger(nameof(ApplicationMonitor)), nativeMethods, new ProcessFactory(ModuleLogger(nameof(ProcessFactory))));
 			var displayMonitor = new DisplayMonitor(ModuleLogger(nameof(DisplayMonitor)), nativeMethods, systemInfo);
 			var explorerShell = new ExplorerShell(ModuleLogger(nameof(ExplorerShell)), nativeMethods);
 			var hashAlgorithm = new HashAlgorithm();

SafeExamBrowser.Client/Operations/ApplicationOperation.cs

@@ -14,6 +14,7 @@ using SafeExamBrowser.Core.Contracts.OperationModel.Events;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.Monitoring.Contracts.Applications;
+using SafeExamBrowser.Settings;
 using SafeExamBrowser.Settings.Applications;
 
 namespace SafeExamBrowser.Client.Operations
@@ -109,18 +110,18 @@ namespace SafeExamBrowser.Client.Operations
 
 		private void StartMonitor()
 		{
-			//TODO: if (Context.Settings.KioskMode != KioskMode.None)
+			if (Context.Settings.KioskMode != KioskMode.None)
-			//{
+			{
 				applicationMonitor.Start();
-			//}
+			}
 		}
 
 		private void StopMonitor()
 		{
-			//TODO: if (Context.Settings.KioskMode != KioskMode.None)
+			if (Context.Settings.KioskMode != KioskMode.None)
-			//{
+			{
 				applicationMonitor.Stop();
-			//}
+			}
 		}
 
 		private OperationResult TryTerminate(IEnumerable<RunningApplication> runningApplications)

SafeExamBrowser.Monitoring.Contracts/Applications/Events/ExplorerStartedEventHandler.cs

@@ -9,7 +9,7 @@
 namespace SafeExamBrowser.Monitoring.Contracts.Applications.Events
 {
 	/// <summary>
-	/// Indicates that the Windows explorer process has started.
+	/// Indicates that the Windows Explorer has been started.
 	/// </summary>
 	public delegate void ExplorerStartedEventHandler();
 }

SafeExamBrowser.Monitoring.Contracts/Applications/Events/TerminationFailedEventHandler.cs

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System.Collections.Generic;
+
+namespace SafeExamBrowser.Monitoring.Contracts.Applications.Events
+{
+	/// <summary>
+	/// Indicates that the given blacklisted applications could not be terminated.
+	/// </summary>
+	public delegate void TerminationFailedEventHandler(IEnumerable<RunningApplication> applications);
+}

SafeExamBrowser.Monitoring.Contracts/Applications/IApplicationMonitor.cs

@@ -21,6 +21,11 @@ namespace SafeExamBrowser.Monitoring.Contracts.Applications
 		/// </summary>
 		event ExplorerStartedEventHandler ExplorerStarted;
 
+		/// <summary>
+		/// Event fired when the automatic termination of a blacklisted application failed.
+		/// </summary>
+		event TerminationFailedEventHandler TerminationFailed;
+
 		/// <summary>
 		/// Initializes the application monitor.
 		/// </summary>

SafeExamBrowser.Monitoring.Contracts/SafeExamBrowser.Monitoring.Contracts.csproj

@@ -53,6 +53,7 @@
     <Reference Include="Microsoft.CSharp" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Applications\Events\TerminationFailedEventHandler.cs" />
     <Compile Include="Applications\RunningApplication.cs" />
     <Compile Include="Display\Events\DisplayChangedEventHandler.cs" />
     <Compile Include="Applications\Events\ExplorerStartedEventHandler.cs" />

SafeExamBrowser.Monitoring/Applications/ApplicationMonitor.cs

@@ -9,6 +9,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using System.Timers;
 using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.Monitoring.Contracts.Applications;
@@ -32,6 +33,7 @@ namespace SafeExamBrowser.Monitoring.Applications
 		private IList<WhitelistApplication> whitelist;
 
 		public event ExplorerStartedEventHandler ExplorerStarted;
+		public event TerminationFailedEventHandler TerminationFailed;
 
 		public ApplicationMonitor(int interval_ms, ILogger logger, INativeMethods nativeMethods, IProcessFactory processFactory)
 		{
@@ -133,6 +135,74 @@ namespace SafeExamBrowser.Monitoring.Applications
 			return success;
 		}
 
+		private void SystemEvent_WindowChanged(IntPtr window)
+		{
+			if (window != IntPtr.Zero && activeWindow != window)
+			{
+				logger.Debug($"Window has changed from {activeWindow} to {window}.");
+				activeWindow = window;
+
+				Task.Run(() =>
+				{
+					if (!IsAllowed(window) && !TryHide(window))
+					{
+						Close(window);
+					}
+				});
+			}
+		}
+
+		private void Timer_Elapsed(object sender, ElapsedEventArgs e)
+		{
+			var failed = new List<RunningApplication>();
+			var running = processFactory.GetAllRunning();
+			var started = running.Where(r => processes.All(p => p.Id != r.Id)).ToList();
+			var terminated = processes.Where(p => running.All(r => r.Id != p.Id)).ToList();
+
+			foreach (var process in started)
+			{
+				logger.Debug($"Process {process} has been started.");
+				processes.Add(process);
+
+				if (process.Name == "explorer")
+				{
+					HandleExplorerStart(process);
+				}
+				else if (!IsAllowed(process) && !TryTerminate(process))
+				{
+					AddFailed(process, failed);
+				}
+			}
+
+			foreach (var process in terminated)
+			{
+				logger.Debug($"Process {process} has been terminated.");
+				processes.Remove(process);
+			}
+
+			if (failed.Any())
+			{
+				logger.Warn($"Failed to terminate these blacklisted applications: {string.Join(", ", failed.Select(a => a.Name))}.");
+				TerminationFailed?.Invoke(failed);
+			}
+
+			timer.Start();
+		}
+
+		private void AddFailed(IProcess process, List<RunningApplication> failed)
+		{
+			var name = blacklist.First(a => BelongsToApplication(process, a)).ExecutableName;
+			var application = failed.FirstOrDefault(a => a.Name == name);
+
+			if (application == default(RunningApplication))
+			{
+				application = new RunningApplication(name);
+				failed.Add(application);
+			}
+
+			application.Processes.Add(process);
+		}
+
 		private void AddFailed(string name, IProcess process, InitializationResult result)
 		{
 			var application = result.FailedAutoTerminations.FirstOrDefault(a => a.Name == name);
@@ -169,21 +239,6 @@ namespace SafeExamBrowser.Monitoring.Applications
 			return sameName || sameOriginalName;
 		}
 
-		private void Check(IntPtr window)
-		{
-			var allowed = IsAllowed(window);
-
-			if (!allowed)
-			{
-				var success = TryHide(window);
-
-				if (!success)
-				{
-					Close(window);
-				}
-			}
-		}
-
 		private void Close(IntPtr window)
 		{
 			var title = nativeMethods.GetWindowTitle(window);
@@ -192,6 +247,23 @@ namespace SafeExamBrowser.Monitoring.Applications
 			logger.Info($"Sent close message to window '{title}' with handle = {window}.");
 		}
 
+		private void HandleExplorerStart(IProcess process)
+		{
+			logger.Warn($"A new instance of Windows Explorer {process} has been started!");
+
+			if (!TryTerminate(process))
+			{
+				var application = new RunningApplication("Windows Explorer");
+
+				logger.Error("Failed to terminate new Windows Explorer instance!");
+				application.Processes.Add(process);
+
+				Task.Run(() => TerminationFailed?.Invoke(new[] { application }));
+			}
+
+			Task.Run(() => ExplorerStarted?.Invoke());
+		}
+
 		private bool IsAllowed(IntPtr window)
 		{
 			var processId = nativeMethods.GetProcessIdFor(window);
@@ -213,6 +285,21 @@ namespace SafeExamBrowser.Monitoring.Applications
 			return true;
 		}
 
+		private bool IsAllowed(IProcess process)
+		{
+			foreach (var application in blacklist)
+			{
+				if (BelongsToApplication(process, application))
+				{
+					logger.Warn($"Process {process} belongs to blacklisted application '{application.ExecutableName}'!");
+
+					return false;
+				}
+			}
+
+			return true;
+		}
+
 		private bool TryHide(IntPtr window)
 		{
 			var title = nativeMethods.GetWindowTitle(window);
@@ -265,51 +352,5 @@ namespace SafeExamBrowser.Monitoring.Applications
 
 			return process.HasTerminated;
 		}
-
-		private void Timer_Elapsed(object sender, ElapsedEventArgs e)
-		{
-			var running = processFactory.GetAllRunning();
-			var started = running.Where(r => processes.All(p => p.Id != r.Id)).ToList();
-			var terminated = processes.Where(p => running.All(r => r.Id != p.Id)).ToList();
-
-			foreach (var process in started)
-			{
-				logger.Debug($"Process {process} has been started.");
-				processes.Add(process);
-
-				foreach (var application in blacklist)
-				{
-					if (BelongsToApplication(process, application))
-					{
-						logger.Warn($"Process {process} belongs to blacklisted application '{application.ExecutableName}'! Attempting termination...");
-
-						var success = TryTerminate(process);
-
-						if (!success)
-						{
-							// TODO: Invoke event -> Show lock screen!
-						}
-					}
-				}
-			}
-
-			foreach (var process in terminated)
-			{
-				logger.Debug($"Process {process} has been terminated.");
-				processes.Remove(process);
-			}
-
-			timer.Start();
-		}
-
-		private void SystemEvent_WindowChanged(IntPtr window)
-		{
-			if (window != IntPtr.Zero && activeWindow != window)
-			{
-				logger.Debug($"Window has changed from {activeWindow} to {window}.");
-				activeWindow = window;
-				Check(window);
-			}
-		}
 	}
 }

SafeExamBrowser.Runtime.UnitTests/Operations/ClientOperationTests.cs

@@ -172,7 +172,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Operations
 
 			proxy.Verify(p => p.InitiateShutdown(), Times.Once);
 			proxy.Verify(p => p.Disconnect(), Times.Once);
-			process.Verify(p => p.TryKill(default(int)), Times.Never);
+			process.Verify(p => p.TryKill(It.IsAny<int>()), Times.Never);
 
 			Assert.IsNull(sessionContext.ClientProcess);
 			Assert.IsNull(sessionContext.ClientProxy);
@@ -181,12 +181,12 @@ namespace SafeExamBrowser.Runtime.UnitTests.Operations
 		[TestMethod]
 		public void Revert_MustKillClientIfStoppingFailed()
 		{
-			process.Setup(p => p.TryKill(default(int))).Callback(() => process.SetupGet(p => p.HasTerminated).Returns(true));
+			process.Setup(p => p.TryKill(It.IsAny<int>())).Callback(() => process.SetupGet(p => p.HasTerminated).Returns(true));
 
 			PerformNormally();
 			sut.Revert();
 
-			process.Verify(p => p.TryKill(default(int)), Times.AtLeastOnce);
+			process.Verify(p => p.TryKill(It.IsAny<int>()), Times.AtLeastOnce);
 
 			Assert.IsNull(sessionContext.ClientProcess);
 			Assert.IsNull(sessionContext.ClientProxy);
@@ -198,7 +198,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Operations
 			PerformNormally();
 			sut.Revert();
 
-			process.Verify(p => p.TryKill(default(int)), Times.Exactly(5));
+			process.Verify(p => p.TryKill(It.IsAny<int>()), Times.Exactly(5));
 
 			Assert.IsNotNull(sessionContext.ClientProcess);
 			Assert.IsNotNull(sessionContext.ClientProxy);
@@ -213,7 +213,7 @@ namespace SafeExamBrowser.Runtime.UnitTests.Operations
 
 			proxy.Verify(p => p.InitiateShutdown(), Times.Never);
 			proxy.Verify(p => p.Disconnect(), Times.Never);
-			process.Verify(p => p.TryKill(default(int)), Times.Never);
+			process.Verify(p => p.TryKill(It.IsAny<int>()), Times.Never);
 
 			Assert.IsNull(sessionContext.ClientProcess);
 			Assert.IsNull(sessionContext.ClientProxy);

SafeExamBrowser.Runtime/Operations/ClientOperation.cs

@@ -248,7 +248,7 @@ namespace SafeExamBrowser.Runtime.Operations
 			{
 				logger.Info($"Attempt {attempt}/{MAX_ATTEMPTS} to kill client process with ID = {ClientProcess.Id}.");
 
-				if (ClientProcess.TryKill())
+				if (ClientProcess.TryKill(500))
 				{
 					break;
 				}