mirror of
https://github.com/aaru-dps/Aaru.git
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288 lines
13 KiB
C#
288 lines
13 KiB
C#
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// /***************************************************************************
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// The Disc Image Chef
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// ----------------------------------------------------------------------------
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//
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// Filename : Read.cs
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// Author(s) : Natalia Portillo <claunia@claunia.com>
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//
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// Component : Disk image plugins.
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//
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// --[ Description ] ----------------------------------------------------------
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//
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// Reads QEMU Copy-On-Write v2 disk images.
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//
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// --[ License ] --------------------------------------------------------------
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//
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// This library is free software; you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 2.1 of the
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// License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, see <http://www.gnu.org/licenses/>.
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//
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// ----------------------------------------------------------------------------
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// Copyright © 2011-2018 Natalia Portillo
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// ****************************************************************************/
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Runtime.InteropServices;
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using DiscImageChef.CommonTypes;
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using DiscImageChef.CommonTypes.Enums;
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using DiscImageChef.CommonTypes.Exceptions;
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using DiscImageChef.CommonTypes.Interfaces;
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using DiscImageChef.Console;
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using SharpCompress.Compressors;
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using SharpCompress.Compressors.Deflate;
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namespace DiscImageChef.DiscImages
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{
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public partial class Qcow2
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{
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public bool Open(IFilter imageFilter)
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{
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Stream stream = imageFilter.GetDataForkStream();
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stream.Seek(0, SeekOrigin.Begin);
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if(stream.Length < 512) return false;
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byte[] qHdrB = new byte[Marshal.SizeOf(qHdr)];
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stream.Read(qHdrB, 0, Marshal.SizeOf(qHdr));
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qHdr = BigEndianMarshal.ByteArrayToStructureBigEndian<QCow2Header>(qHdrB);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.magic = 0x{0:X8}", qHdr.magic);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.version = {0}", qHdr.version);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.backing_file_offset = {0}", qHdr.backing_file_offset);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.backing_file_size = {0}", qHdr.backing_file_size);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.cluster_bits = {0}", qHdr.cluster_bits);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.size = {0}", qHdr.size);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.crypt_method = {0}", qHdr.crypt_method);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1_size = {0}", qHdr.l1_size);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1_table_offset = {0}", qHdr.l1_table_offset);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.refcount_table_offset = {0}", qHdr.refcount_table_offset);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.refcount_table_clusters = {0}",
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qHdr.refcount_table_clusters);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.nb_snapshots = {0}", qHdr.nb_snapshots);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.snapshots_offset = {0}", qHdr.snapshots_offset);
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if(qHdr.version >= QCOW_VERSION3)
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{
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.features = {0:X}", qHdr.features);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.compat_features = {0:X}", qHdr.compat_features);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.autoclear_features = {0:X}", qHdr.autoclear_features);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.refcount_order = {0}", qHdr.refcount_order);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.header_length = {0}", qHdr.header_length);
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if((qHdr.features & QCOW_FEATURE_MASK) != 0)
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throw new
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ImageNotSupportedException($"Unknown incompatible features {qHdr.features & QCOW_FEATURE_MASK:X} enabled, not proceeding.");
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}
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if(qHdr.size <= 1) throw new ArgumentOutOfRangeException(nameof(qHdr.size), "Image size is too small");
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if(qHdr.cluster_bits < 9 || qHdr.cluster_bits > 16)
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throw new ArgumentOutOfRangeException(nameof(qHdr.cluster_bits),
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"Cluster size must be between 512 bytes and 64 Kbytes");
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if(qHdr.crypt_method > QCOW_ENCRYPTION_AES)
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throw new ArgumentOutOfRangeException(nameof(qHdr.crypt_method), "Invalid encryption method");
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if(qHdr.crypt_method > QCOW_ENCRYPTION_NONE)
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throw new NotImplementedException("AES encrypted images not yet supported");
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if(qHdr.backing_file_offset != 0)
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throw new NotImplementedException("Differencing images not yet supported");
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clusterSize = 1 << (int)qHdr.cluster_bits;
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clusterSectors = 1 << ((int)qHdr.cluster_bits - 9);
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l2Bits = (int)(qHdr.cluster_bits - 3);
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l2Size = 1 << l2Bits;
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.clusterSize = {0}", clusterSize);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.clusterSectors = {0}", clusterSectors);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.qHdr.l1_size = {0}", qHdr.l1_size);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l2Size = {0}", l2Size);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.sectors = {0}", imageInfo.Sectors);
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BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
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byte[] l1TableB = new byte[qHdr.l1_size * 8];
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stream.Seek((long)qHdr.l1_table_offset, SeekOrigin.Begin);
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stream.Read(l1TableB, 0, (int)qHdr.l1_size * 8);
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l1Table = new ulong[qHdr.l1_size];
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// TODO: Optimize this
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DicConsole.DebugWriteLine("QCOW plugin", "Reading L1 table");
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for(long i = 0; i < l1Table.LongLength; i++)
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l1Table[i] = BigEndianBitConverter.ToUInt64(l1TableB, (int)(i * 8));
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l1Mask = 0;
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int c = 0;
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l1Shift = (int)(l2Bits + qHdr.cluster_bits);
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for(int i = 0; i < 64; i++)
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{
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l1Mask <<= 1;
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if(c >= 64 - l1Shift) continue;
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l1Mask += 1;
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c++;
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}
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l2Mask = 0;
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for(int i = 0; i < l2Bits; i++) l2Mask = (l2Mask << 1) + 1;
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l2Mask <<= (int)qHdr.cluster_bits;
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sectorMask = 0;
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for(int i = 0; i < qHdr.cluster_bits; i++) sectorMask = (sectorMask << 1) + 1;
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1Mask = {0:X}", l1Mask);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l1Shift = {0}", l1Shift);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.l2Mask = {0:X}", l2Mask);
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DicConsole.DebugWriteLine("QCOW plugin", "qHdr.sectorMask = {0:X}", sectorMask);
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maxL2TableCache = MAX_CACHE_SIZE / (l2Size * 8);
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maxClusterCache = MAX_CACHE_SIZE / clusterSize;
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imageStream = stream;
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sectorCache = new Dictionary<ulong, byte[]>();
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l2TableCache = new Dictionary<ulong, ulong[]>();
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clusterCache = new Dictionary<ulong, byte[]>();
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imageInfo.CreationTime = imageFilter.GetCreationTime();
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imageInfo.LastModificationTime = imageFilter.GetLastWriteTime();
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imageInfo.MediaTitle = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
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imageInfo.Sectors = qHdr.size / 512;
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imageInfo.SectorSize = 512;
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imageInfo.XmlMediaType = XmlMediaType.BlockMedia;
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imageInfo.MediaType = MediaType.GENERIC_HDD;
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imageInfo.ImageSize = qHdr.size;
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imageInfo.Version = $"{qHdr.version}";
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imageInfo.Cylinders = (uint)(imageInfo.Sectors / 16 / 63);
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imageInfo.Heads = 16;
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imageInfo.SectorsPerTrack = 63;
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return true;
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}
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public byte[] ReadSector(ulong sectorAddress)
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{
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if(sectorAddress > imageInfo.Sectors - 1)
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throw new ArgumentOutOfRangeException(nameof(sectorAddress),
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$"Sector address {sectorAddress} not found");
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// Check cache
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if(sectorCache.TryGetValue(sectorAddress, out byte[] sector)) return sector;
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ulong byteAddress = sectorAddress * 512;
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ulong l1Off = (byteAddress & l1Mask) >> l1Shift;
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if((long)l1Off >= l1Table.LongLength)
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throw new ArgumentOutOfRangeException(nameof(l1Off),
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$"Trying to read past L1 table, position {l1Off} of a max {l1Table.LongLength}");
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// TODO: Implement differential images
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if(l1Table[l1Off] == 0) return new byte[512];
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if(!l2TableCache.TryGetValue(l1Off, out ulong[] l2Table))
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{
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l2Table = new ulong[l2Size];
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imageStream.Seek((long)(l1Table[l1Off] & QCOW_FLAGS_MASK), SeekOrigin.Begin);
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byte[] l2TableB = new byte[l2Size * 8];
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imageStream.Read(l2TableB, 0, l2Size * 8);
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DicConsole.DebugWriteLine("QCOW plugin", "Reading L2 table #{0}", l1Off);
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for(long i = 0; i < l2Table.LongLength; i++)
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l2Table[i] = BigEndianBitConverter.ToUInt64(l2TableB, (int)(i * 8));
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if(l2TableCache.Count >= maxL2TableCache) l2TableCache.Clear();
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l2TableCache.Add(l1Off, l2Table);
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}
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ulong l2Off = (byteAddress & l2Mask) >> (int)qHdr.cluster_bits;
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ulong offset = l2Table[l2Off];
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sector = new byte[512];
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if((offset & QCOW_FLAGS_MASK) != 0)
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{
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if(!clusterCache.TryGetValue(offset, out byte[] cluster))
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{
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if((offset & QCOW_COMPRESSED) == QCOW_COMPRESSED)
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{
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ulong compSizeMask = (ulong)(1 << (int)(qHdr.cluster_bits - 8)) - 1;
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byte countbits = (byte)(qHdr.cluster_bits - 8);
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compSizeMask <<= 62 - countbits;
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ulong offMask = ~compSizeMask & QCOW_FLAGS_MASK;
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ulong realOff = offset & offMask;
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ulong compSize = (((offset & compSizeMask) >> (62 - countbits)) + 1) * 512;
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byte[] zCluster = new byte[compSize];
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imageStream.Seek((long)realOff, SeekOrigin.Begin);
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imageStream.Read(zCluster, 0, (int)compSize);
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DeflateStream zStream =
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new DeflateStream(new MemoryStream(zCluster), CompressionMode.Decompress);
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cluster = new byte[clusterSize];
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int read = zStream.Read(cluster, 0, clusterSize);
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if(read != clusterSize)
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throw new
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IOException($"Unable to decompress cluster, expected {clusterSize} bytes got {read}");
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}
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else
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{
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cluster = new byte[clusterSize];
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imageStream.Seek((long)(offset & QCOW_FLAGS_MASK), SeekOrigin.Begin);
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imageStream.Read(cluster, 0, clusterSize);
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}
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if(clusterCache.Count >= maxClusterCache) clusterCache.Clear();
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clusterCache.Add(offset, cluster);
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}
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Array.Copy(cluster, (int)(byteAddress & sectorMask), sector, 0, 512);
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}
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if(sectorCache.Count >= MAX_CACHED_SECTORS) sectorCache.Clear();
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sectorCache.Add(sectorAddress, sector);
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return sector;
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}
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public byte[] ReadSectors(ulong sectorAddress, uint length)
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{
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if(sectorAddress > imageInfo.Sectors - 1)
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throw new ArgumentOutOfRangeException(nameof(sectorAddress),
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$"Sector address {sectorAddress} not found");
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if(sectorAddress + length > imageInfo.Sectors)
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throw new ArgumentOutOfRangeException(nameof(length), "Requested more sectors than available");
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MemoryStream ms = new MemoryStream();
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for(uint i = 0; i < length; i++)
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{
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byte[] sector = ReadSector(sectorAddress + i);
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ms.Write(sector, 0, sector.Length);
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}
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return ms.ToArray();
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}
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}
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}
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