148 lines
3.1 KiB
C#
148 lines
3.1 KiB
C#
/*
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* Copyright (c) 2020 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Threading.Tasks;
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using SafeExamBrowser.Lockdown.Contracts;
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using SafeExamBrowser.Logging.Contracts;
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namespace SafeExamBrowser.Lockdown
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{
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public class FeatureConfigurationMonitor : IFeatureConfigurationMonitor
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{
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private readonly object @lock = new object();
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private IDictionary<IFeatureConfiguration, FeatureConfigurationStatus> configurations;
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private ILogger logger;
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private readonly int timeout_ms;
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private bool running;
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public FeatureConfigurationMonitor(ILogger logger, int timeout_ms)
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{
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if (timeout_ms < 0)
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{
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throw new ArgumentException("Must be 0 or greater!", nameof(timeout_ms));
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}
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this.configurations = new Dictionary<IFeatureConfiguration, FeatureConfigurationStatus>();
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this.logger = logger;
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this.timeout_ms = timeout_ms;
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}
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public void Observe(IFeatureConfiguration configuration, FeatureConfigurationStatus status)
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{
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lock (@lock)
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{
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configurations.Add(configuration, status);
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}
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}
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public void Reset()
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{
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lock (@lock)
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{
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if (running)
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{
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running = false;
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configurations.Clear();
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logger.Info("Stopped monitoring.");
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}
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else
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{
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logger.Info("Monitoring is not running.");
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}
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}
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}
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public void Start()
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{
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lock (@lock)
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{
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if (!running)
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{
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running = true;
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Task.Run(new Action(Monitor));
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logger.Info("Started monitoring.");
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}
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else
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{
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logger.Info("Monitoring is already running.");
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}
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}
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}
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private void Monitor()
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{
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if (IsStopped())
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{
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return;
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}
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var configurations = new Dictionary<IFeatureConfiguration, FeatureConfigurationStatus>(this.configurations);
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logger.Debug($"Checking {configurations.Count} configurations...");
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foreach (var item in configurations)
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{
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var configuration = item.Key;
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var status = item.Value;
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Enforce(configuration, status);
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if (IsStopped())
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{
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logger.Info("Monitoring was aborted.");
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return;
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}
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}
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if (configurations.Any())
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{
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Task.Delay(timeout_ms).ContinueWith((_) => Monitor());
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}
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else
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{
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lock (@lock)
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{
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running = false;
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logger.Info("Nothing to be monitored, stopped monitoring.");
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}
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}
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}
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private void Enforce(IFeatureConfiguration configuration, FeatureConfigurationStatus status)
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{
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var currentStatus = configuration.GetStatus();
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if (currentStatus != status)
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{
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logger.Warn($"{configuration} is {currentStatus.ToString().ToLower()} instead of {status.ToString().ToLower()}!");
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if (status == FeatureConfigurationStatus.Disabled)
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{
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configuration.DisableFeature();
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}
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else if (status == FeatureConfigurationStatus.Enabled)
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{
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configuration.EnableFeature();
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}
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}
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}
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private bool IsStopped()
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{
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lock (@lock)
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{
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return !running;
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}
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}
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}
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}
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