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

434 lines
17 KiB
C#

#region Disclaimer / License
// Copyright (C) 2011, Kenneth Skovhede
// http://www.hexad.dk, opensource@hexad.dk
//
// 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.Text;
using System.IO;
using Alphaleonis.Win32.Vss;
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 class WindowsSnapshot : ISnapshotService
{
/// <summary>
/// The main reference to the backup controller
/// </summary>
private IVssBackupComponents m_backup;
/// <summary>
/// The list of paths that will be shadow copied
/// </summary>
private string[] m_sourcepaths;
/// <summary>
/// The list of snapshot ids for each volume, key is the path root, eg C:\.
/// The dictionary is case insensitive
/// </summary>
private 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 Dictionary<string, string> m_volumeMap;
/// <summary>
/// A list of mapped drives
/// </summary>
private List<DefineDosDevice> m_mappedDrives;
/// <summary>
/// Commonly used string element
/// </summary>
private static string SLASH = Path.DirectorySeparatorChar.ToString();
/// <summary>
/// A cached lookup for windows methods for dealing with long filenames
/// </summary>
private static readonly SystemIOWindows _ioWin = new SystemIOWindows();
/// <summary>
/// Constructs a new backup snapshot, using all the required disks
/// </summary>
/// <param name="sourcepaths">The folders that are about to be backed up</param>
/// <param name="options">A set of commandline options</param>
public WindowsSnapshot(string[] sourcepaths, Dictionary<string, string> options)
{
try
{
//Substitute for calling VssUtils.LoadImplementation(), as we have the dlls outside the GAC
string alphadir = Path.Combine(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), "alphavss");
string alphadll = System.IO.Path.Combine(alphadir, VssUtils.GetPlatformSpecificAssemblyShortName() + ".dll");
IVssImplementation vss = (IVssImplementation)System.Reflection.Assembly.LoadFile(alphadll).CreateInstance("Alphaleonis.Win32.Vss.VssImplementation");
List<Guid> excludedWriters = new List<Guid>();
if (options.ContainsKey("vss-exclude-writers"))
{
foreach (string s in options["vss-exclude-writers"].Split(';'))
if (!string.IsNullOrEmpty(s) && s.Trim().Length > 0)
excludedWriters.Add(new Guid(s));
}
//Check if we should map any drives
bool useSubst = Utility.Utility.ParseBoolOption(options, "vss-use-mapping");
//Prepare the backup
m_backup = vss.CreateVssBackupComponents();
m_backup.InitializeForBackup(null);
if (excludedWriters.Count > 0)
m_backup.DisableWriterClasses(excludedWriters.ToArray());
m_backup.StartSnapshotSet();
m_sourcepaths = new string[sourcepaths.Length];
for(int i = 0; i < m_sourcepaths.Length; i++)
m_sourcepaths[i] = System.IO.Directory.Exists(sourcepaths[i]) ? Utility.Utility.AppendDirSeparator(sourcepaths[i]) : sourcepaths[i];
try
{
//Gather information on all Vss writers
m_backup.GatherWriterMetadata();
m_backup.FreeWriterMetadata();
}
catch
{
try { m_backup.FreeWriterMetadata(); }
catch { }
throw;
}
//Figure out which volumes are in the set
m_volumes = new Dictionary<string, Guid>(StringComparer.InvariantCultureIgnoreCase);
foreach (string s in m_sourcepaths)
{
string drive = Alphaleonis.Win32.Filesystem.Path.GetPathRoot(s);
if (!m_volumes.ContainsKey(drive))
{
if (!m_backup.IsVolumeSupported(drive))
throw new VssVolumeNotSupportedException(drive);
m_volumes.Add(drive, m_backup.AddToSnapshotSet(drive));
}
}
//Signal that we want to do a backup
m_backup.SetBackupState(false, true, VssBackupType.Full, false);
//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.InvariantCultureIgnoreCase);
foreach(KeyValuePair<string, Guid> kvp in m_volumes)
m_volumeMap.Add(kvp.Key, m_backup.GetSnapshotProperties(kvp.Value).SnapshotDeviceObject);
//If we should map the drives, we do that now and update the volumeMap
if (useSubst)
{
m_mappedDrives = new List<DefineDosDevice>();
foreach (string 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 { }
}
}
}
catch
{
//In case we fail in the constructor, we do not want a snapshot to be active
try { Dispose(); }
catch { }
throw;
}
}
#if DEBUG
/// <summary>
/// Returns all files found in the shadow copies
/// </summary>
/// <returns>A list of filenames to files found in the shadow volumes</returns>
public List<string> AllFiles()
{
return EnumerateFilesAndFolders(null).ToList();
}
#endif
#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="folder">The non-shadow path of the folder to list</param>
/// <returns>A list of non-shadow paths</returns>
private string[] ListFolders(string folder)
{
string root = Utility.Utility.AppendDirSeparator(Alphaleonis.Win32.Filesystem.Path.GetPathRoot(folder));
string volumePath = Utility.Utility.AppendDirSeparator(GetSnapshotPath(root));
string[] tmp = null;
string spath = GetSnapshotPath(folder);
if (SystemIOWindows.IsPathTooLong(spath))
try { tmp = Alphaleonis.Win32.Filesystem.Directory.GetDirectories(spath); }
catch (PathTooLongException) { }
catch (DirectoryNotFoundException) { }
else
try { tmp = System.IO.Directory.GetDirectories(spath); }
catch (PathTooLongException) { }
if (tmp == null)
{
spath = SystemIOWindows.PrefixWithUNC(spath);
volumePath = SystemIOWindows.PrefixWithUNC(volumePath);
tmp = Alphaleonis.Win32.Filesystem.Directory.GetDirectories(spath);
}
for (int i = 0; i < tmp.Length; i++)
tmp[i] = root + 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="folder">The non-shadow path of the folder to list</param>
/// <returns>A list of non-shadow paths</returns>
private string[] ListFiles(string folder)
{
string root = Utility.Utility.AppendDirSeparator(Alphaleonis.Win32.Filesystem.Path.GetPathRoot(folder));
string volumePath = Utility.Utility.AppendDirSeparator(GetSnapshotPath(root));
string[] tmp = null;
string spath = GetSnapshotPath(folder);
if (SystemIOWindows.IsPathTooLong(spath))
try { tmp = Alphaleonis.Win32.Filesystem.Directory.GetFiles(spath); }
catch (PathTooLongException) { }
catch (DirectoryNotFoundException) { }
else
try { tmp = System.IO.Directory.GetFiles(spath); }
catch (PathTooLongException) { }
if (tmp == null)
{
spath = SystemIOWindows.PrefixWithUNC(spath);
volumePath = SystemIOWindows.PrefixWithUNC(volumePath);
tmp = Alphaleonis.Win32.Filesystem.Directory.GetFiles(spath);
}
for (int i = 0; i < tmp.Length; i++)
tmp[i] = root + tmp[i].Substring(volumePath.Length);
return tmp;
}
/// <summary>
/// Helper function to translate a local path into the corresponding shadow volume path
/// </summary>
/// <param name="localPath">The local path to convert</param>
/// <returns>The corresponding shadow volume path</returns>
private string GetSnapshotPath(string localPath)
{
if (!Path.IsPathRooted(localPath))
throw new InvalidOperationException();
string root = Alphaleonis.Win32.Filesystem.Path.GetPathRoot(localPath);
string volumePath;
if (!m_volumeMap.TryGetValue(root, out volumePath))
throw new InvalidOperationException();
localPath = localPath.Replace(root, String.Empty);
if (!volumePath.EndsWith(SLASH) && !localPath.StartsWith(SLASH))
localPath = localPath.Insert(0, SLASH);
localPath = localPath.Insert(0, volumePath);
return localPath;
}
#endregion
#region ISnapshotService Members
/// <summary>
/// Enumerates all files and folders in the shadow copy
/// </summary>
/// <param name="filter">The filter to apply when evaluating files and folders</param>
/// <param name="callback">The callback to invoke with each found path</param>
public IEnumerable<string> EnumerateFilesAndFolders(Utility.Utility.EnumerationFilterDelegate callback)
{
return m_sourcepaths.SelectMany(
s => Utility.Utility.EnumerateFileSystemEntries(s, callback, this.ListFolders, this.ListFiles, this.GetAttributes)
);
}
/// <summary>
/// Gets the last write time of a given file in UTC
/// </summary>
/// <param name="file">The full path to the file in non-shadow format</param>
/// <returns>The last write time of the file</returns>
public DateTime GetLastWriteTimeUtc(string file)
{
string spath = GetSnapshotPath(file);
if (!SystemIOWindows.IsPathTooLong(spath))
try
{
return File.GetLastWriteTimeUtc(spath);
}
catch (PathTooLongException) { }
return Alphaleonis.Win32.Filesystem.File.GetLastWriteTimeUtc(SystemIOWindows.PrefixWithUNC(spath));
}
/// <summary>
/// Opens a file for reading
/// </summary>
/// <param name="file">The full path to the file in non-shadow format</param>
/// <returns>An open filestream that can be read</returns>
public System.IO.Stream OpenRead(string file)
{
return _ioWin.FileOpenRead(GetSnapshotPath(file));
}
/// <summary>
/// Returns the size of a file
/// </summary>
/// <param name="file">The full path to the file in non-snapshot format</param>
/// <returns>The lenth of the file</returns>
public long GetFileSize(string file)
{
return _ioWin.FileLength(GetSnapshotPath(file));
}
/// <summary>
/// Gets the attributes for the given file or folder
/// </summary>
/// <returns>The file attributes</returns>
/// <param name="file">The file or folder to examine</param>
public System.IO.FileAttributes GetAttributes(string file)
{
return _ioWin.GetFileAttributes(GetSnapshotPath(file));
}
/// <summary>
/// Returns the symlink target if the entry is a symlink, and null otherwise
/// </summary>
/// <param name="file">The file or folder to examine</param>
/// <returns>The symlink target</returns>
public string GetSymlinkTarget(string file)
{
string spath = GetSnapshotPath(file);
try
{
return Alphaleonis.Win32.Filesystem.File.GetLinkTargetInfo(spath).PrintName;
}
catch (PathTooLongException) { }
return Alphaleonis.Win32.Filesystem.File.GetLinkTargetInfo(SystemIOWindows.PrefixWithUNC(spath)).PrintName;
}
/// <summary>
/// Gets the metadata for the given file or folder
/// </summary>
/// <returns>The metadata for the given file or folder</returns>
/// <param name="file">The file or folder to examine</param>
public Dictionary<string, string> GetMetadata(string file)
{
return null;
}
/// <summary>
/// Gets a value indicating if the path points to a block device
/// </summary>
/// <returns><c>true</c> if this instance is a block device; otherwise, <c>false</c>.</returns>
/// <param name="file">The file or folder to examine</param>
public bool IsBlockDevice(string file)
{
return false;
}
#endregion
#region IDisposable Members
/// <summary>
/// Cleans up any resources and closes the backup set
/// </summary>
public void Dispose()
{
try
{
if (m_mappedDrives != null)
{
foreach (DefineDosDevice d in m_mappedDrives)
d.Dispose();
m_mappedDrives = null;
m_volumeMap = null;
}
}
catch { }
try
{
if (m_backup != null)
m_backup.BackupComplete();
}
catch { }
try
{
if (m_backup != null)
foreach (Guid g in m_volumes.Values)
try { m_backup.DeleteSnapshot(g, false); }
catch { }
}
catch { }
if (m_backup != null)
{
m_backup.Dispose();
m_backup = null;
}
}
#endregion
}
}