Files
duplicati/Duplicati/Library/Snapshots/WindowsSnapshot.cs
T

497 lines
19 KiB
C#

#region Disclaimer / License
// Copyright (C) 2015, The Duplicati Team
// http://www.duplicati.com, info@duplicati.com
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
using System.Linq;
#endregion
using System;
using System.Collections.Generic;
using System.IO;
using Alphaleonis.Win32.Vss;
using AlphaFS = Alphaleonis.Win32.Filesystem;
namespace Duplicati.Library.Snapshots
{
/// <summary>
/// This class encapsulates all access to the Windows Volume Shadow copy Services,
/// implementing the disposable patterns to ensure correct release of resources.
///
/// The class presents all files and folders with their regular filenames to the caller,
/// and internally handles the conversion to the shadow path.
/// </summary>
public sealed class WindowsSnapshot : SnapshotBase
{
/// <summary>
/// The tag used for logging messages
/// </summary>
public static readonly string LOGTAG = Logging.Log.LogTagFromType<WindowsSnapshot>();
/// <summary>
/// The main reference to the backup controller
/// </summary>
private IVssBackupComponents m_backup;
/// <summary>
/// The list of snapshot ids for each volume, key is the path root, eg C:\.
/// The dictionary is case insensitive
/// </summary>
private readonly Dictionary<string, Guid> m_volumes;
/// <summary>
/// The mapping of snapshot sources to their snapshot entries , key is the path root, eg C:\.
/// The dictionary is case insensitive
/// </summary>
private readonly Dictionary<string, string> m_volumeMap;
/// <summary>
/// The mapping of snapshot sources to their snapshot entries , key is the path root, eg C:\.
/// The dictionary is case insensitive
/// </summary>
private readonly Dictionary<string, string> m_volumeReverseMap;
/// <summary>
/// A list of mapped drives
/// </summary>
private List<DefineDosDevice> m_mappedDrives;
/// <summary>
/// A cached lookup for windows methods for dealing with long filenames
/// </summary>
private static SystemIOWindows IO_WIN = new SystemIOWindows();
/// <summary>
/// Constructs a new backup snapshot, using all the required disks
/// </summary>
/// <param name="sources">Sources to determine which volumes to include in snapshot</param>
/// <param name="options">A set of commandline options</param>
public WindowsSnapshot(IEnumerable<string> sources, IDictionary<string, string> options)
{
try
{
// Substitute for calling VssUtils.LoadImplementation(), as we have the dlls outside the GAC
var assemblyLocation = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
if (assemblyLocation == null)
throw new InvalidOperationException();
var alphadir = Path.Combine(assemblyLocation, "alphavss");
var alphadll = Path.Combine(alphadir, VssUtils.GetPlatformSpecificAssemblyShortName() + ".dll");
var vss = (IVssImplementation)System.Reflection.Assembly.LoadFile(alphadll).CreateInstance("Alphaleonis.Win32.Vss.VssImplementation");
if (vss == null)
throw new InvalidOperationException();
var excludedWriters = new Guid[0];
if (options.ContainsKey("vss-exclude-writers"))
{
excludedWriters = options["vss-exclude-writers"].Split(';').Where(x => !string.IsNullOrWhiteSpace(x) && x.Trim().Length > 0).Select(x => new Guid(x)).ToArray();
}
//Check if we should map any drives
var useSubst = Utility.Utility.ParseBoolOption(options, "vss-use-mapping");
//Prepare the backup
m_backup = vss.CreateVssBackupComponents();
m_backup.InitializeForBackup(null);
m_backup.SetContext(VssSnapshotContext.Backup);
m_backup.SetBackupState(false, true, VssBackupType.Full, false);
if (excludedWriters.Length > 0)
m_backup.DisableWriterClasses(excludedWriters.ToArray());
try
{
m_backup.GatherWriterMetadata();
}
finally
{
m_backup.FreeWriterMetadata();
}
m_backup.StartSnapshotSet();
//Figure out which volumes are in the set
m_volumes = new Dictionary<string, Guid>(StringComparer.OrdinalIgnoreCase);
foreach (var s in sources)
{
var drive = AlphaFS.Path.GetPathRoot(s);
if (!m_volumes.ContainsKey(drive))
{
//TODO: that seems a bit harsh... we could fall-back to not using VSS for that volume only
if (!m_backup.IsVolumeSupported(drive))
throw new VssVolumeNotSupportedException(drive);
m_volumes.Add(drive, m_backup.AddToSnapshotSet(drive));
}
}
//Make all writers aware that we are going to do the backup
m_backup.PrepareForBackup();
//Create the shadow volumes
m_backup.DoSnapshotSet();
//Make a little lookup table for faster translation
m_volumeMap = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
foreach (var kvp in m_volumes)
{
m_volumeMap.Add(kvp.Key, m_backup.GetSnapshotProperties(kvp.Value).SnapshotDeviceObject);
}
m_volumeReverseMap = m_volumeMap.ToDictionary(x => x.Value, x => x.Key);
//If we should map the drives, we do that now and update the volumeMap
if (useSubst)
{
m_mappedDrives = new List<DefineDosDevice>();
foreach (var k in new List<string>(m_volumeMap.Keys))
{
try
{
DefineDosDevice d;
m_mappedDrives.Add(d = new DefineDosDevice(m_volumeMap[k]));
m_volumeMap[k] = Utility.Utility.AppendDirSeparator(d.Drive);
}
catch(Exception ex)
{
Logging.Log.WriteVerboseMessage(LOGTAG, "SubstMappingfailed", ex, "Failed to map VSS path {0} to drive", k);
}
}
}
}
catch
{
//In case we fail in the constructor, we do not want a snapshot to be active
try
{
Dispose();
}
catch(Exception ex)
{
Logging.Log.WriteVerboseMessage(LOGTAG, "VSSCleanupOnError", ex, "Failed during VSS error cleanup");
}
throw;
}
}
#region Private functions
/// <summary>
/// A callback function that takes a non-shadow path to a folder,
/// and returns all folders found in a non-shadow path format.
/// </summary>
/// <param name="localFolderPath">The non-shadow path of the folder to list</param>
/// <returns>A list of non-shadow paths</returns>
protected override string[] ListFolders(string localFolderPath)
{
var root = Utility.Utility.AppendDirSeparator(AlphaFS.Path.GetPathRoot(localFolderPath));
var volumePath = Utility.Utility.AppendDirSeparator(ConvertToSnapshotPath(root));
string[] tmp = null;
var spath = ConvertToSnapshotPath(localFolderPath);
if (SystemIOWindows.IsPathTooLong(spath))
{
try { tmp = AlphaFS.Directory.GetDirectories(spath); }
catch (PathTooLongException) { }
catch (DirectoryNotFoundException) { }
}
else
{
try { tmp = Directory.GetDirectories(spath); }
catch (PathTooLongException) { }
}
if (tmp == null)
{
spath = SystemIOWindows.PrefixWithUNC(spath);
tmp = AlphaFS.Directory.GetDirectories(spath);
}
volumePath = SystemIOWindows.PrefixWithUNC(volumePath);
for (var i = 0; i < tmp.Length; i++)
{
tmp[i] = root + SystemIOWindows.PrefixWithUNC(tmp[i]).Substring(volumePath.Length);
}
return tmp;
}
/// <summary>
/// A callback function that takes a non-shadow path to a folder,
/// and returns all files found in a non-shadow path format.
/// </summary>
/// <param name="localFolderPath">The non-shadow path of the folder to list</param>
/// <returns>A list of non-shadow paths</returns>
protected override string[] ListFiles(string localFolderPath)
{
var root = Utility.Utility.AppendDirSeparator(AlphaFS.Path.GetPathRoot(localFolderPath));
var volumePath = Utility.Utility.AppendDirSeparator(ConvertToSnapshotPath(root));
string[] tmp = null;
var spath = ConvertToSnapshotPath(localFolderPath);
if (SystemIOWindows.IsPathTooLong(spath))
{
try { tmp = AlphaFS.Directory.GetFiles(spath); }
catch (PathTooLongException) { }
catch (DirectoryNotFoundException) { }
}
else
{
try { tmp = Directory.GetFiles(spath); }
catch (PathTooLongException) { }
}
if (tmp == null)
{
spath = SystemIOWindows.PrefixWithUNC(spath);
tmp = AlphaFS.Directory.GetFiles(spath);
}
volumePath = SystemIOWindows.PrefixWithUNC(volumePath);
for (var i = 0; i < tmp.Length; i++)
{
tmp[i] = root + SystemIOWindows.PrefixWithUNC(tmp[i]).Substring(volumePath.Length);
}
return tmp;
}
#endregion
#region ISnapshotService Members
/// <summary>
/// Gets the last write time of a given file in UTC
/// </summary>
/// <param name="localPath">The full path to the file in non-shadow format</param>
/// <returns>The last write time of the file</returns>
public override DateTime GetLastWriteTimeUtc(string localPath)
{
var spath = ConvertToSnapshotPath(localPath);
if (!SystemIOWindows.IsPathTooLong(spath))
{
try
{
return File.GetLastWriteTimeUtc(spath);
}
catch (PathTooLongException) { }
}
return AlphaFS.File.GetLastWriteTimeUtc(SystemIOWindows.PrefixWithUNC(spath));
}
/// <summary>
/// Gets the creation of a given file in UTC
/// </summary>
/// <param name="localPath">The full path to the file in non-shadow format</param>
/// <returns>The last write time of the file</returns>
public override DateTime GetCreationTimeUtc(string localPath)
{
var spath = ConvertToSnapshotPath(localPath);
if (!SystemIOWindows.IsPathTooLong(spath))
{
try
{
return File.GetCreationTimeUtc(spath);
}
catch (PathTooLongException) { }
}
return AlphaFS.File.GetCreationTimeUtc(SystemIOWindows.PrefixWithUNC(spath));
}
/// <summary>
/// Opens a file for reading
/// </summary>
/// <param name="localPath">The full path to the file in non-shadow format</param>
/// <returns>An open filestream that can be read</returns>
public override Stream OpenRead(string localPath)
{
return IO_WIN.FileOpenRead(ConvertToSnapshotPath(localPath));
}
/// <summary>
/// Returns the size of a file
/// </summary>
/// <param name="localPath">The full path to the file in non-snapshot format</param>
/// <returns>The lenth of the file</returns>
public override long GetFileSize(string localPath)
{
return IO_WIN.FileLength(ConvertToSnapshotPath(localPath));
}
/// <summary>
/// Gets the attributes for the given file or folder
/// </summary>
/// <returns>The file attributes</returns>
/// <param name="localPath">The file or folder to examine</param>
public override FileAttributes GetAttributes(string localPath)
{
return IO_WIN.GetFileAttributes(ConvertToSnapshotPath(localPath));
}
/// <summary>
/// Returns the symlink target if the entry is a symlink, and null otherwise
/// </summary>
/// <param name="localPath">The file or folder to examine</param>
/// <returns>The symlink target</returns>
public override string GetSymlinkTarget(string localPath)
{
var spath = ConvertToSnapshotPath(localPath);
return IO_WIN.GetSymlinkTarget(spath);
}
/// <summary>
/// Gets the metadata for the given file or folder
/// </summary>
/// <returns>The metadata for the given file or folder</returns>
/// <param name="localPath">The file or folder to examine</param>
/// <param name="isSymlink">A flag indicating if the target is a symlink</param>
/// <param name="followSymlink">A flag indicating if a symlink should be followed</param>
public override Dictionary<string, string> GetMetadata(string localPath, bool isSymlink, bool followSymlink)
{
return IO_WIN.GetMetadata(ConvertToSnapshotPath(localPath), isSymlink, followSymlink);
}
/// <inheritdoc />
public override bool IsBlockDevice(string localPath)
{
return false;
}
/// <inheritdoc />
public override string HardlinkTargetID(string localPath)
{
return null;
}
/// <inheritdoc />
public override string ConvertToLocalPath(string snapshotPath)
{
if (!Path.IsPathRooted(snapshotPath))
throw new InvalidOperationException();
foreach (var kvp in m_volumeReverseMap)
{
if (snapshotPath.StartsWith(kvp.Key, Utility.Utility.ClientFilenameStringComparison))
return Path.Combine(kvp.Value, snapshotPath.Substring(kvp.Key.Length));
}
throw new InvalidOperationException();
}
/// <inheritdoc />
public override string ConvertToSnapshotPath(string localPath)
{
if (!Path.IsPathRooted(localPath))
throw new InvalidOperationException();
var root = AlphaFS.Path.GetPathRoot(localPath);
if (!m_volumeMap.TryGetValue(root, out var volumePath))
throw new InvalidOperationException();
return Path.Combine(volumePath, localPath.Substring(root.Length));
}
/// <inheritdoc />
public override bool FileExists(string localFilePath)
{
return IO_WIN.FileExists(ConvertToSnapshotPath(localFilePath));
}
/// <inheritdoc />
public override bool DirectoryExists(string localFolderPath)
{
return IO_WIN.DirectoryExists(ConvertToSnapshotPath(localFolderPath));
}
/// <inheritdoc />
public override bool IsSnapshot => true;
#endregion
/// <inheritdoc />
protected override void Dispose(bool disposing)
{
if (disposing)
{
try
{
if (m_mappedDrives != null)
{
foreach (var d in m_mappedDrives)
{
d.Dispose();
}
m_mappedDrives = null;
}
}
catch (Exception ex)
{
Logging.Log.WriteVerboseMessage(LOGTAG, "MappedDriveCleanupError", ex, "Failed during VSS mapped drive unmapping");
}
try
{
m_backup?.BackupComplete();
}
catch (Exception ex)
{
Logging.Log.WriteVerboseMessage(LOGTAG, "VSSTerminateError", ex, "Failed to signal VSS completion");
}
try
{
if (m_backup != null)
{
foreach (var g in m_volumes.Values)
{
try
{
m_backup.DeleteSnapshot(g, false);
}
catch (Exception ex)
{
Logging.Log.WriteVerboseMessage(LOGTAG, "VSSSnapShotDeleteError", ex, "Failed to close VSS snapshot");
}
}
}
}
catch (Exception ex)
{
Logging.Log.WriteVerboseMessage(LOGTAG, "VSSSnapShotDeleteCleanError", ex, "Failed during VSS esnapshot closing");
}
if (m_backup != null)
{
m_backup.Dispose();
m_backup = null;
}
}
base.Dispose(disposing);
}
}
}