DSInternals/Src/DSInternals.DataStore/DirectoryContext.cs

308 lines
12 KiB
C#

namespace DSInternals.DataStore
{
using System;
using System.IO;
using Microsoft.Database.Isam;
using Microsoft.Isam.Esent.Interop;
public class DirectoryContext : IDisposable
{
private const string JetInstanceName = "DSInternals";
private IsamInstance instance;
private IsamSession session;
private IsamDatabase database;
private bool isDBAttached = false;
/// <summary>
/// Creates a new Active Directory database context.
/// </summary>
/// <param name="dbPath">dbFilePath must point to the DIT file on the local computer.</param>
/// <param name="logPath">The path should point to a writeable folder on the local computer, where ESE log files will be created. If not specified, then temp folder will be used.</param>
public DirectoryContext(string dbFilePath, bool readOnly, string logDirectoryPath = null)
{
if (!File.Exists(dbFilePath))
{
throw new FileNotFoundException("The specified database file does not exist.", dbFilePath);
}
this.DSADatabaseFile = dbFilePath;
ValidateDatabaseState(this.DSADatabaseFile);
this.DSAWorkingDirectory = Path.GetDirectoryName(this.DSADatabaseFile);
string checkpointDirectoryPath = this.DSAWorkingDirectory;
string tempDatabasePath = Path.Combine(this.DSAWorkingDirectory, ADConstants.EseTempDatabaseName);
this.DatabaseLogFilesPath = logDirectoryPath;
if (this.DatabaseLogFilesPath != null)
{
if (!Directory.Exists(this.DatabaseLogFilesPath))
{
throw new FileNotFoundException("The specified log directory does not exist.", this.DatabaseLogFilesPath);
}
}
else
{
// Use the default location if an alternate log directory is not provided.
this.DatabaseLogFilesPath = this.DSAWorkingDirectory;
}
// Note: IsamInstance constructor throws AccessDenied Exception when the path does not end with a backslash.
this.instance = new IsamInstance(AddPathSeparator(checkpointDirectoryPath), AddPathSeparator(this.DatabaseLogFilesPath), tempDatabasePath, ADConstants.EseBaseName, JetInstanceName, readOnly, ADConstants.PageSize);
try
{
var isamParameters = this.instance.IsamSystemParameters;
// Set the size of the transaction log files to AD defaults.
isamParameters.LogFileSize = ADConstants.EseLogFileSize;
// Delete the log files that are not matching (generation wise) during soft recovery.
isamParameters.DeleteOutOfRangeLogs = true;
// Check the database for indexes over Unicode key columns that were built using an older version of the NLS library.
isamParameters.EnableIndexChecking2 = true;
// Automatically clean up indexes over Unicode key columns as necessary to avoid database format changes caused by changes to the NLS library.
isamParameters.EnableIndexCleanup = true;
// Retain only transaction log files that are younger than the current checkpoint.
isamParameters.CircularLog = true;
// Disable all database engine callbacks to application provided functions. This enables us to open Win2016 DBs on non-DC systems.
isamParameters.DisableCallbacks = true;
// Increase the limit of maximum open tables.
isamParameters.MaxOpenTables = ADConstants.EseMaxOpenTables;
// Enable backwards compatibility with the file naming conventions of earlier releases of the database engine.
isamParameters.LegacyFileNames = ADConstants.EseLegacyFileNames;
// Set EN-US to be used by any index over a Unicode key column.
isamParameters.UnicodeIndexDefault = new JET_UNICODEINDEX()
{
lcid = ADConstants.EseIndexDefaultLocale,
dwMapFlags = ADConstants.EseIndexDefaultCompareOptions
};
// Force crash recovery to look for the database referenced in the transaction log in the specified folder.
isamParameters.AlternateDatabaseRecoveryPath = this.DSAWorkingDirectory;
if (!readOnly)
{
// Delete obsolete log files.
isamParameters.DeleteOldLogs = true;
if (EsentVersion.SupportsWindows10Features)
{
try
{
// Required for Windows Server 2022 compatibility, as it limits the transaction log file format to 8920.
// Note: Usage of JET_efvUsePersistedFormat still causes minor DB format upgrade.
isamParameters.EngineFormatVersion = 0x40000002; // JET_efvUsePersistedFormat: Instructs the engine to use the minimal Engine Format Version of all loaded log and DB files.
}
catch (EsentInvalidParameterException)
{
// JET_efvUsePersistedFormat should be supported since Windows Server 2016.
// Just continue even if it is not supported on the current Windows build.
}
}
}
this.session = this.instance.CreateSession();
this.session.AttachDatabase(this.DSADatabaseFile);
this.isDBAttached = true;
this.database = this.session.OpenDatabase(this.DSADatabaseFile);
this.Schema = new DirectorySchema(this.database);
this.SecurityDescriptorRersolver = new SecurityDescriptorRersolver(this.database);
this.DistinguishedNameResolver = new DistinguishedNameResolver(this.database, this.Schema);
this.LinkResolver = new LinkResolver(this.database, this.Schema);
this.DomainController = new DomainController(this);
}
catch (EsentFileAccessDeniedException e)
{
// This exception was probably thrown by the OpenDatabase method
// HACK: Do not dispose the IsamSession object. Its Dispose method would throw an exception, which is a bug in ISAM.
GC.SuppressFinalize(this.session);
this.session = null;
// Free resources if anything failed
this.Dispose();
throw;
}
catch (EsentErrorException e)
{
// Free resources if anything failed
this.Dispose();
// EsentUnicodeTranslationFailException - This typically happens while opening a Windows Server 2003 DIT on a newer system.
// EsentSecondaryIndexCorruptedException - This typically happens when opening a Windows Server 2012 R2 DIT on Windows 7.
throw new InvalidDatabaseStateException("There was a problem reading the database, which probably comes from a different OS. Try defragmenting it first by running the 'esentutl /d ntds.dit' command.", this.DSADatabaseFile, e);
}
catch
{
// Free resources if anything failed
this.Dispose();
throw;
}
}
public string DSAWorkingDirectory
{
get;
private set;
}
public string DSADatabaseFile
{
get;
private set;
}
public string DatabaseLogFilesPath
{
get;
private set;
}
public DirectorySchema Schema
{
get;
private set;
}
public LinkResolver LinkResolver
{
get;
private set;
}
public DomainController DomainController
{
get;
private set;
}
public DistinguishedNameResolver DistinguishedNameResolver
{
get;
private set;
}
public SecurityDescriptorRersolver SecurityDescriptorRersolver
{
get;
private set;
}
public Cursor OpenDataTable()
{
return this.database.OpenCursor(ADConstants.DataTableName);
}
public Cursor OpenLinkTable()
{
return this.database.OpenCursor(ADConstants.LinkTableName);
}
public Cursor OpenSystemTable()
{
return this.database.OpenCursor(ADConstants.SystemTableName);
}
public IsamTransaction BeginTransaction()
{
return new IsamTransaction(this.session);
}
public void Dispose()
{
this.Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!disposing)
{
// Do nothing
return;
}
if(this.LinkResolver != null)
{
this.LinkResolver.Dispose();
this.LinkResolver = null;
}
if (this.SecurityDescriptorRersolver != null)
{
this.SecurityDescriptorRersolver.Dispose();
this.SecurityDescriptorRersolver = null;
}
if (this.DistinguishedNameResolver != null)
{
this.DistinguishedNameResolver.Dispose();
this.DistinguishedNameResolver = null;
}
if (this.DomainController != null)
{
this.DomainController.Dispose();
this.DomainController = null;
}
if (this.database != null)
{
this.database.Dispose();
this.database = null;
}
if (this.session != null)
{
if (this.isDBAttached)
{
this.session.DetachDatabase(this.DSADatabaseFile);
this.isDBAttached = false;
}
this.session.Dispose();
this.session = null;
}
if (this.instance != null)
{
this.instance.Dispose();
this.instance = null;
}
}
private static string AddPathSeparator(string path)
{
if (string.IsNullOrEmpty(path) || path.EndsWith(Path.DirectorySeparatorChar.ToString()))
{
// No need to add path separator
return path;
}
else
{
return path + Path.DirectorySeparatorChar;
}
}
public static void ValidateDatabaseState(string dbFilePath)
{
// Retrieve info about the DB (Win Version, Page Size, State,...)
JET_DBINFOMISC dbInfo;
Api.JetGetDatabaseFileInfo(dbFilePath, out dbInfo, JET_DbInfo.Misc);
if (dbInfo.dbstate != JET_dbstate.CleanShutdown)
{
// Database might be inconsistent
throw new InvalidDatabaseStateException("The database is not in a clean state. Try to recover it first by running the 'esentutl /r edb /d' command.", dbFilePath);
}
}
}
}