Files
Aaru/DiscImageChef.DiscImages/QCOW2.cs

692 lines
25 KiB
C#

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename : QCOW2.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
// Manages QEMU Copy-On-Write v2 disk images.
//
// --[ License ] --------------------------------------------------------------
//
// 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, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2018 Natalia Portillo
// ****************************************************************************/
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using DiscImageChef.CommonTypes;
using DiscImageChef.Console;
using DiscImageChef.Filters;
using SharpCompress.Compressors;
using SharpCompress.Compressors.Deflate;
namespace DiscImageChef.DiscImages
{
public class Qcow2 : ImagePlugin
{
#region Internal constants
/// <summary>
/// Magic number: 'Q', 'F', 'I', 0xFB
/// </summary>
const uint QCOW_MAGIC = 0x514649FB;
const uint QCOW_VERSION2 = 2;
const uint QCOW_VERSION3 = 3;
const uint QCOW_ENCRYPTION_NONE = 0;
const uint QCOW_ENCRYPTION_AES = 1;
const ulong QCOW_FEATURE_DIRTY = 0x01;
const ulong QCOW_FEATURE_CORRUPT = 0x02;
const ulong QCOW_FEATURE_MASK = 0xFFFFFFFFFFFFFFFC;
const ulong QCOW_COMPAT_FEATURE_LAZY_REFCOUNTS = 0x01;
const ulong QCOW_AUTO_CLEAR_FEATURE_BITMAP = 0x01;
const ulong QCOW_FLAGS_MASK = 0x3FFFFFFFFFFFFFFF;
const ulong QCOW_COPIED = 0x8000000000000000;
const ulong QCOW_COMPRESSED = 0x4000000000000000;
const ulong QCOW_HEADER_EXTENSION_BACKING_FILE = 0xE2792ACA;
const ulong QCOW_HEADER_EXTENSION_FEATURE_TABLE = 0x6803F857;
const ulong QCOW_HEADER_EXTENSION_BITMAPS = 0x23852875;
const int MAX_CACHE_SIZE = 16777216;
#endregion
#region Internal Structures
/// <summary>
/// QCOW header, big-endian
/// </summary>
[StructLayout(LayoutKind.Sequential, Pack = 1)]
struct QCow2Header
{
/// <summary>
/// <see cref="Qcow2.QCOW_MAGIC"/>
/// </summary>
public uint magic;
/// <summary>
/// Must be 1
/// </summary>
public uint version;
/// <summary>
/// Offset inside file to string containing backing file
/// </summary>
public ulong backing_file_offset;
/// <summary>
/// Size of <see cref="backing_file_offset"/>
/// </summary>
public uint backing_file_size;
/// <summary>
/// Cluster bits
/// </summary>
public uint cluster_bits;
/// <summary>
/// Size in bytes
/// </summary>
public ulong size;
/// <summary>
/// Encryption method
/// </summary>
public uint crypt_method;
/// <summary>
/// Size of L1 table
/// </summary>
public uint l1_size;
/// <summary>
/// Offset to L1 table
/// </summary>
public ulong l1_table_offset;
/// <summary>
/// Offset to reference count table
/// </summary>
public ulong refcount_table_offset;
/// <summary>
/// How many clusters does the refcount table span
/// </summary>
public uint refcount_table_clusters;
/// <summary>
/// Number of snapshots
/// </summary>
public uint nb_snapshots;
/// <summary>
/// Offset to QCowSnapshotHeader
/// </summary>
public ulong snapshots_offset;
// Added in version 3
public ulong features;
public ulong compat_features;
public ulong autoclear_features;
public uint refcount_order;
public uint header_length;
}
#endregion
QCow2Header qHdr;
int clusterSize;
int clusterSectors;
int l2Bits;
int l2Size;
ulong[] l1Table;
ulong l1Mask;
int l1Shift;
ulong l2Mask;
ulong sectorMask;
Dictionary<ulong, byte[]> sectorCache;
Dictionary<ulong, byte[]> clusterCache;
Dictionary<ulong, ulong[]> l2TableCache;
const int MAX_CACHED_SECTORS = MAX_CACHE_SIZE / 512;
int maxL2TableCache;
int maxClusterCache;
Stream imageStream;
public Qcow2()
{
Name = "QEMU Copy-On-Write disk image v2";
PluginUuid = new Guid("F20107CB-95B3-4398-894B-975261F1E8C5");
ImageInfo = new ImageInfo
{
ReadableSectorTags = new List<SectorTagType>(),
ReadableMediaTags = new List<MediaTagType>(),
ImageHasPartitions = false,
ImageHasSessions = false,
ImageVersion = null,
ImageApplication = "QEMU",
ImageApplicationVersion = null,
ImageCreator = null,
ImageComments = null,
MediaManufacturer = null,
MediaModel = null,
MediaSerialNumber = null,
MediaBarcode = null,
MediaPartNumber = null,
MediaSequence = 0,
LastMediaSequence = 0,
DriveManufacturer = null,
DriveModel = null,
DriveSerialNumber = null,
DriveFirmwareRevision = null
};
}
public override bool IdentifyImage(Filter imageFilter)
{
Stream stream = imageFilter.GetDataForkStream();
stream.Seek(0, SeekOrigin.Begin);
if(stream.Length < 512) return false;
byte[] qHdrB = new byte[Marshal.SizeOf(qHdr)];
stream.Read(qHdrB, 0, Marshal.SizeOf(qHdr));
qHdr = BigEndianMarshal.ByteArrayToStructureBigEndian<QCow2Header>(qHdrB);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.magic = 0x{0:X8}", qHdr.magic);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.version = {0}", qHdr.version);
return qHdr.magic == QCOW_MAGIC && (qHdr.version == QCOW_VERSION2 || qHdr.version == QCOW_VERSION3);
}
public override bool OpenImage(Filter imageFilter)
{
Stream stream = imageFilter.GetDataForkStream();
stream.Seek(0, SeekOrigin.Begin);
if(stream.Length < 512) return false;
byte[] qHdrB = new byte[Marshal.SizeOf(qHdr)];
stream.Read(qHdrB, 0, Marshal.SizeOf(qHdr));
qHdr = BigEndianMarshal.ByteArrayToStructureBigEndian<QCow2Header>(qHdrB);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.magic = 0x{0:X8}", qHdr.magic);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.version = {0}", qHdr.version);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.backing_file_offset = {0}", qHdr.backing_file_offset);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.backing_file_size = {0}", qHdr.backing_file_size);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.cluster_bits = {0}", qHdr.cluster_bits);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.size = {0}", qHdr.size);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.crypt_method = {0}", qHdr.crypt_method);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1_size = {0}", qHdr.l1_size);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1_table_offset = {0}", qHdr.l1_table_offset);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.refcount_table_offset = {0}", qHdr.refcount_table_offset);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.refcount_table_clusters = {0}",
qHdr.refcount_table_clusters);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.nb_snapshots = {0}", qHdr.nb_snapshots);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.snapshots_offset = {0}", qHdr.snapshots_offset);
if(qHdr.version >= QCOW_VERSION3)
{
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.features = {0:X}", qHdr.features);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.compat_features = {0:X}", qHdr.compat_features);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.autoclear_features = {0:X}", qHdr.autoclear_features);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.refcount_order = {0}", qHdr.refcount_order);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.header_length = {0}", qHdr.header_length);
if((qHdr.features & QCOW_FEATURE_MASK) != 0)
throw new
ImageNotSupportedException($"Unknown incompatible features {qHdr.features & QCOW_FEATURE_MASK:X} enabled, not proceeding.");
}
if(qHdr.size <= 1) throw new ArgumentOutOfRangeException(nameof(qHdr.size), "Image size is too small");
if(qHdr.cluster_bits < 9 || qHdr.cluster_bits > 16)
throw new ArgumentOutOfRangeException(nameof(qHdr.cluster_bits),
"Cluster size must be between 512 bytes and 64 Kbytes");
if(qHdr.crypt_method > QCOW_ENCRYPTION_AES)
throw new ArgumentOutOfRangeException(nameof(qHdr.crypt_method), "Invalid encryption method");
if(qHdr.crypt_method > QCOW_ENCRYPTION_NONE)
throw new NotImplementedException("AES encrypted images not yet supported");
if(qHdr.backing_file_offset != 0)
throw new NotImplementedException("Differencing images not yet supported");
int shift = (int)(qHdr.cluster_bits + l2Bits);
if(qHdr.size > ulong.MaxValue - (ulong)(1 << shift))
throw new ArgumentOutOfRangeException(nameof(qHdr.size), "Image is too large");
clusterSize = 1 << (int)qHdr.cluster_bits;
clusterSectors = 1 << ((int)qHdr.cluster_bits - 9);
l2Bits = (int)(qHdr.cluster_bits - 3);
l2Size = 1 << l2Bits;
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.clusterSize = {0}", clusterSize);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.clusterSectors = {0}", clusterSectors);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.qHdr.l1_size = {0}", qHdr.l1_size);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l2Size = {0}", l2Size);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.sectors = {0}", ImageInfo.Sectors);
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
byte[] l1TableB = new byte[qHdr.l1_size * 8];
stream.Seek((long)qHdr.l1_table_offset, SeekOrigin.Begin);
stream.Read(l1TableB, 0, (int)qHdr.l1_size * 8);
l1Table = new ulong[qHdr.l1_size];
// TODO: Optimize this
DicConsole.DebugWriteLine("QCOW plugin", "Reading L1 table");
for(long i = 0; i < l1Table.LongLength; i++)
l1Table[i] = BigEndianBitConverter.ToUInt64(l1TableB, (int)(i * 8));
l1Mask = 0;
int c = 0;
l1Shift = (int)(l2Bits + qHdr.cluster_bits);
for(int i = 0; i < 64; i++)
{
l1Mask <<= 1;
if(c >= 64 - l1Shift) continue;
l1Mask += 1;
c++;
}
l2Mask = 0;
for(int i = 0; i < l2Bits; i++) l2Mask = (l2Mask << 1) + 1;
l2Mask <<= (int)qHdr.cluster_bits;
sectorMask = 0;
for(int i = 0; i < qHdr.cluster_bits; i++) sectorMask = (sectorMask << 1) + 1;
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1Mask = {0:X}", l1Mask);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1Shift = {0}", l1Shift);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l2Mask = {0:X}", l2Mask);
DicConsole.DebugWriteLine("QCOW plugin", "qHdr.sectorMask = {0:X}", sectorMask);
maxL2TableCache = MAX_CACHE_SIZE / (l2Size * 8);
maxClusterCache = MAX_CACHE_SIZE / clusterSize;
imageStream = stream;
sectorCache = new Dictionary<ulong, byte[]>();
l2TableCache = new Dictionary<ulong, ulong[]>();
clusterCache = new Dictionary<ulong, byte[]>();
ImageInfo.ImageCreationTime = imageFilter.GetCreationTime();
ImageInfo.ImageLastModificationTime = imageFilter.GetLastWriteTime();
ImageInfo.ImageName = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
ImageInfo.Sectors = qHdr.size / 512;
ImageInfo.SectorSize = 512;
ImageInfo.XmlMediaType = XmlMediaType.BlockMedia;
ImageInfo.MediaType = MediaType.GENERIC_HDD;
ImageInfo.ImageSize = qHdr.size;
ImageInfo.ImageVersion = $"{qHdr.version}";
ImageInfo.Cylinders = (uint)(ImageInfo.Sectors / 16 / 63);
ImageInfo.Heads = 16;
ImageInfo.SectorsPerTrack = 63;
return true;
}
public override byte[] ReadSector(ulong sectorAddress)
{
if(sectorAddress > ImageInfo.Sectors - 1)
throw new ArgumentOutOfRangeException(nameof(sectorAddress),
$"Sector address {sectorAddress} not found");
// Check cache
if(sectorCache.TryGetValue(sectorAddress, out byte[] sector)) return sector;
ulong byteAddress = sectorAddress * 512;
ulong l1Off = (byteAddress & l1Mask) >> l1Shift;
if((long)l1Off >= l1Table.LongLength)
throw new ArgumentOutOfRangeException(nameof(l1Off),
$"Trying to read past L1 table, position {l1Off} of a max {l1Table.LongLength}");
// TODO: Implement differential images
if(l1Table[l1Off] == 0) return new byte[512];
if(!l2TableCache.TryGetValue(l1Off, out ulong[] l2Table))
{
l2Table = new ulong[l2Size];
imageStream.Seek((long)(l1Table[l1Off] & QCOW_FLAGS_MASK), SeekOrigin.Begin);
byte[] l2TableB = new byte[l2Size * 8];
imageStream.Read(l2TableB, 0, l2Size * 8);
DicConsole.DebugWriteLine("QCOW plugin", "Reading L2 table #{0}", l1Off);
for(long i = 0; i < l2Table.LongLength; i++)
l2Table[i] = BigEndianBitConverter.ToUInt64(l2TableB, (int)(i * 8));
if(l2TableCache.Count >= maxL2TableCache) l2TableCache.Clear();
l2TableCache.Add(l1Off, l2Table);
}
ulong l2Off = (byteAddress & l2Mask) >> (int)qHdr.cluster_bits;
ulong offset = l2Table[l2Off];
sector = new byte[512];
if((offset & QCOW_FLAGS_MASK) != 0)
{
if(!clusterCache.TryGetValue(offset, out byte[] cluster))
{
if((offset & QCOW_COMPRESSED) == QCOW_COMPRESSED)
{
ulong compSizeMask;
ulong offMask;
compSizeMask = (ulong)(1 << (int)(qHdr.cluster_bits - 8)) - 1;
byte countbits = (byte)(qHdr.cluster_bits - 8);
compSizeMask <<= 62 - countbits;
offMask = ~compSizeMask & QCOW_FLAGS_MASK;
ulong realOff = offset & offMask;
ulong compSize = (((offset & compSizeMask) >> (62 - countbits)) + 1) * 512;
byte[] zCluster = new byte[compSize];
imageStream.Seek((long)realOff, SeekOrigin.Begin);
imageStream.Read(zCluster, 0, (int)compSize);
DeflateStream zStream =
new DeflateStream(new MemoryStream(zCluster), CompressionMode.Decompress);
cluster = new byte[clusterSize];
int read = zStream.Read(cluster, 0, clusterSize);
if(read != clusterSize)
throw new
IOException($"Unable to decompress cluster, expected {clusterSize} bytes got {read}");
}
else
{
cluster = new byte[clusterSize];
imageStream.Seek((long)(offset & QCOW_FLAGS_MASK), SeekOrigin.Begin);
imageStream.Read(cluster, 0, clusterSize);
}
if(clusterCache.Count >= maxClusterCache) clusterCache.Clear();
clusterCache.Add(offset, cluster);
}
Array.Copy(cluster, (int)(byteAddress & sectorMask), sector, 0, 512);
}
if(sectorCache.Count >= MAX_CACHED_SECTORS) sectorCache.Clear();
sectorCache.Add(sectorAddress, sector);
return sector;
}
public override byte[] ReadSectors(ulong sectorAddress, uint length)
{
if(sectorAddress > ImageInfo.Sectors - 1)
throw new ArgumentOutOfRangeException(nameof(sectorAddress),
$"Sector address {sectorAddress} not found");
if(sectorAddress + length > ImageInfo.Sectors)
throw new ArgumentOutOfRangeException(nameof(length), "Requested more sectors than available");
MemoryStream ms = new MemoryStream();
for(uint i = 0; i < length; i++)
{
byte[] sector = ReadSector(sectorAddress + i);
ms.Write(sector, 0, sector.Length);
}
return ms.ToArray();
}
public override bool ImageHasPartitions()
{
return false;
}
public override ulong GetImageSize()
{
return ImageInfo.ImageSize;
}
public override ulong GetSectors()
{
return ImageInfo.Sectors;
}
public override uint GetSectorSize()
{
return ImageInfo.SectorSize;
}
public override string GetImageFormat()
{
return "QEMU Copy-On-Write";
}
public override string GetImageVersion()
{
return ImageInfo.ImageVersion;
}
public override string GetImageApplication()
{
return ImageInfo.ImageApplication;
}
public override string GetImageApplicationVersion()
{
return ImageInfo.ImageApplicationVersion;
}
public override string GetImageCreator()
{
return ImageInfo.ImageCreator;
}
public override DateTime GetImageCreationTime()
{
return ImageInfo.ImageCreationTime;
}
public override DateTime GetImageLastModificationTime()
{
return ImageInfo.ImageLastModificationTime;
}
public override string GetImageName()
{
return ImageInfo.ImageName;
}
public override string GetImageComments()
{
return ImageInfo.ImageComments;
}
public override MediaType GetMediaType()
{
return ImageInfo.MediaType;
}
#region Unsupported features
public override byte[] ReadSectorTag(ulong sectorAddress, SectorTagType tag)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorsTag(ulong sectorAddress, uint length, SectorTagType tag)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadDiskTag(MediaTagType tag)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSector(ulong sectorAddress, uint track)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorTag(ulong sectorAddress, uint track, SectorTagType tag)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectors(ulong sectorAddress, uint length, uint track)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorsTag(ulong sectorAddress, uint length, uint track, SectorTagType tag)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorLong(ulong sectorAddress)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorLong(ulong sectorAddress, uint track)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorsLong(ulong sectorAddress, uint length)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override byte[] ReadSectorsLong(ulong sectorAddress, uint length, uint track)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override string GetMediaManufacturer()
{
return null;
}
public override string GetMediaModel()
{
return null;
}
public override string GetMediaSerialNumber()
{
return null;
}
public override string GetMediaBarcode()
{
return null;
}
public override string GetMediaPartNumber()
{
return null;
}
public override int GetMediaSequence()
{
return 0;
}
public override int GetLastDiskSequence()
{
return 0;
}
public override string GetDriveManufacturer()
{
return null;
}
public override string GetDriveModel()
{
return null;
}
public override string GetDriveSerialNumber()
{
return null;
}
public override List<Partition> GetPartitions()
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override List<Track> GetTracks()
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override List<Track> GetSessionTracks(Session session)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override List<Track> GetSessionTracks(ushort session)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override List<Session> GetSessions()
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override bool? VerifySector(ulong sectorAddress)
{
return null;
}
public override bool? VerifySector(ulong sectorAddress, uint track)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override bool? VerifySectors(ulong sectorAddress, uint length, out List<ulong> failingLbas,
out List<ulong> unknownLbas)
{
failingLbas = new List<ulong>();
unknownLbas = new List<ulong>();
for(ulong i = 0; i < ImageInfo.Sectors; i++) unknownLbas.Add(i);
return null;
}
public override bool? VerifySectors(ulong sectorAddress, uint length, uint track, out List<ulong> failingLbas,
out List<ulong> unknownLbas)
{
throw new FeatureUnsupportedImageException("Feature not supported by image format");
}
public override bool? VerifyMediaImage()
{
return null;
}
#endregion
}
}