//******************************************************************************************************//  AdoSecurityCache.cs - Gbtc////  Copyright © 2013, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://www.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  12/30/2013 - J. Ritchie Carroll//       Generated original version of source code.////****************************************************************************************************** using System;using System.Configuration;using System.Data;using System.IO;using System.Security.Cryptography;using GSF.Configuration;using GSF.Data;using GSF.IO;using GSF.Threading; namespace GSF.Security{    /// <summary>    /// Represents a secured inter-process cache for the security context needed by the <see cref="AdoSecurityProvider"/>.    /// </summary>    /// <remarks>    /// This is a system cache that contains the last known security information loaded from the database related to users,    /// roles and groups. This cache allows the <see cref="AdoSecurityProvider"/> to start-up without database access    /// using latest cached security context. Even though this cache contains role information for all users, it does    /// not overlap information in the <see cref="UserRoleCache"/> since the user role cache contains role assignments    /// for a user at last login and is used for auditing.    /// </remarks>    public class AdoSecurityCache : InterprocessCache    {        #region [ Members ]         // Constants         // Default ADO security cache file name        private const string DefaultCacheFileName = "AdoSecurityCache.bin";         // Fields        private DataSet m_dataSet;              // Internal ADO security data set        private readonly object m_dataSetLock;  // Lock object for internal data set         #endregion         /// <summary>        /// Creates a new instance of the <see cref="AdoSecurityCache"/> with the specified number of <paramref name="maximumConcurrentLocks"/>.        /// </summary>        /// <param name="maximumConcurrentLocks">Maximum concurrent reader locks to allow.</param>        public AdoSecurityCache(int maximumConcurrentLocks = InterprocessReaderWriterLock.DefaultMaximumConcurrentLocks)            : base(maximumConcurrentLocks)        {            m_dataSet = new DataSet("AdoSecurityContext");            m_dataSetLock = new object();        }         #region [ Properties ]         /// <summary>        /// Gets or sets the internal <see cref="DataSet"/>; returned value will be a copy of the internal.        /// </summary>        public DataSet DataSet        {            get            {                DataSet dataSet;                 // We wait until the data set cache is loaded before attempting to access it                WaitForDataReady();                 // Wait for thread level lock on data set                lock (m_dataSetLock)                {                    // Since user could changes, make a copy of the data set for external use                    dataSet = m_dataSet.Copy();                }                 return dataSet;            }            set            {                // Wait for thread level lock on data set                lock (m_dataSetLock)                {                    // Assign new data set                    m_dataSet = value;                }                 // Queue up a serialization for this new data set                Save();            }        }         #endregion         #region [ Methods ]         /// <summary>        /// Initiates inter-process synchronized save of <see cref="DataSet"/>.        /// </summary>        public override void Save()        {            byte[] serializedDataSet;             // Wait for thread level lock on data set            lock (m_dataSetLock)            {                using (BlockAllocatedMemoryStream stream = new BlockAllocatedMemoryStream())                {                    m_dataSet.SerializeToStream(stream);                    serializedDataSet = stream.ToArray();                }            }             // File data is the serialized data set, assignment will initiate auto-save if needed            FileData = serializedDataSet;        }         /// <summary>        /// Handles serialization of file to disk; virtual method allows customization (e.g., pre-save encryption and/or data merge).        /// </summary>        /// <param name="fileStream"><see cref="FileStream"/> used to serialize data.</param>        /// <param name="fileData">File data to be serialized.</param>        /// <remarks>        /// Consumers overriding this method should not directly call <see cref="InterprocessCache.FileData"/> property to avoid potential dead-locks.        /// </remarks>        protected override void SaveFileData(FileStream fileStream, byte[] fileData)        {            // Encrypt data local to this machine (this way user cannot copy ADO security cache to another machine)            base.SaveFileData(fileStream, ProtectedData.Protect(fileData, null, DataProtectionScope.LocalMachine));        }         /// <summary>        /// Handles deserialization of file from disk; virtual method allows customization (e.g., pre-load decryption and/or data merge).        /// </summary>        /// <param name="fileStream"><see cref="FileStream"/> used to deserialize data.</param>        /// <returns>Deserialized file data.</returns>        /// <remarks>        /// Consumers overriding this method should not directly call <see cref="InterprocessCache.FileData"/> property to avoid potential dead-locks.        /// </remarks>        protected override byte[] LoadFileData(FileStream fileStream)        {            // Decrypt data that was encrypted local to this machine            byte[] serializedDataSet = ProtectedData.Unprotect(fileStream.ReadStream(), null, DataProtectionScope.LocalMachine);            DataSet dataSet;             using (MemoryStream stream = new MemoryStream(serializedDataSet))            {                dataSet = stream.DeserializeToDataSet();            }             // Wait for thread level lock on data set            lock (m_dataSetLock)            {                m_dataSet = dataSet;            }             return serializedDataSet;        }         // Waits until the cache is loaded before attempting to access it        private void WaitForDataReady()        {            try            {                // Just wrapping this method to provide a more detailed exception message if there is an issue loading cache                WaitForLoad();            }            catch (Exception ex)            {                throw new UnauthorizedAccessException("ADO security cache access failure: timeout while attempting to load last valid security context.", ex);            }        }         #endregion         #region [ Static ]         // Static Methods         /// <summary>        /// Loads the <see cref="AdoSecurityCache"/> for the current local user.        /// </summary>        /// <returns>Loaded instance of the <see cref="AdoSecurityCache"/>.</returns>        public static AdoSecurityCache GetCurrentCache()        {            AdoSecurityCache currentCache;            AdoSecurityCache localSecurityCache = null;             // Define default cache path            string cachePath = null;             try            {                // Attempt to retrieve configuration cache path as defined in the config file                ConfigurationFile configFile = ConfigurationFile.Current;                CategorizedSettingsElementCollection systemSettings = configFile.Settings["systemSettings"];                CategorizedSettingsElement configurationCachePathSetting = systemSettings["ConfigurationCachePath"];                 if ((object)configurationCachePathSetting != null)                    cachePath = FilePath.GetAbsolutePath(systemSettings["ConfigurationCachePath"].Value);                 if (string.IsNullOrEmpty(cachePath))                    cachePath = string.Format("{0}{1}ConfigurationCache{1}", FilePath.GetAbsolutePath(""), Path.DirectorySeparatorChar);            }            catch (ConfigurationErrorsException)            {                cachePath = string.Format("{0}{1}ConfigurationCache{1}", FilePath.GetAbsolutePath(""), Path.DirectorySeparatorChar);            }             string localCacheFileName = Path.Combine(cachePath, DefaultCacheFileName);             try            {                // Make sure configuration cache path exists                if (!Directory.Exists(cachePath))                    Directory.CreateDirectory(cachePath);                 // Initialize local ADO security cache (application may only have read-only access to this cache)                localSecurityCache = new AdoSecurityCache                {                    FileName = localCacheFileName,                    ReloadOnChange = false,                    AutoSave = false                };                 // Load initial ADO security data set                localSecurityCache.Load();                 // Validate that current user has write access to the local cache folder                string tempFile = FilePath.GetDirectoryName(localCacheFileName) + Guid.NewGuid() + ".tmp";                 using (File.Create(tempFile))                {                }                 if (File.Exists(tempFile))                    File.Delete(tempFile);                 // No access issues exist, use local cache as the primary cache                currentCache = localSecurityCache;                currentCache.AutoSave = true;                localSecurityCache = null;            }            catch (UnauthorizedAccessException)            {                // User does not have needed serialization access to common cache folder,                // use a path where user will have rights                string userCacheFolder = FilePath.AddPathSuffix(FilePath.GetApplicationDataFolder());                string userCacheFileName = userCacheFolder + FilePath.GetFileName(localCacheFileName);                 // Make sure user directory exists                if (!Directory.Exists(userCacheFolder))                    Directory.CreateDirectory(userCacheFolder);                 // Copy existing common cache if none exists                if (File.Exists(localCacheFileName) && !File.Exists(userCacheFileName))                    File.Copy(localCacheFileName, userCacheFileName);                 // Initialize primary cache within user folder                currentCache = new AdoSecurityCache                {                    FileName = userCacheFileName,                    ReloadOnChange = false,                    AutoSave = true                };                 // Load initial ADO security data set                currentCache.Load();                 // Update user located security cache if locally located security cache is newer                if ((object)localSecurityCache != null && File.Exists(localCacheFileName) && File.Exists(userCacheFileName) && File.GetLastWriteTime(localCacheFileName) > File.GetLastWriteTime(userCacheFileName))                    currentCache.DataSet = localSecurityCache.DataSet;            }             if ((object)localSecurityCache != null)                localSecurityCache.Dispose();             return currentCache;        }         #endregion    }}