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Aaru/DiscImageChef.DiscImages/VHD/Read.cs

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// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename : Read.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
// Reads Connectix and Microsoft Virtual PC 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 © 2011-2019 Natalia Portillo
// ****************************************************************************/
using System;
using System.IO;
using System.Text;
using DiscImageChef.Checksums;
using DiscImageChef.CommonTypes;
using DiscImageChef.CommonTypes.Enums;
using DiscImageChef.CommonTypes.Exceptions;
using DiscImageChef.CommonTypes.Interfaces;
using DiscImageChef.Console;
using DiscImageChef.Helpers;
namespace DiscImageChef.DiscImages
{
public partial class Vhd
{
public bool Open(IFilter imageFilter)
{
Stream imageStream = imageFilter.GetDataForkStream();
byte[] header = new byte[512];
byte[] footer;
imageStream.Seek(0, SeekOrigin.Begin);
imageStream.Read(header, 0, 512);
if(imageStream.Length % 2 == 0)
{
footer = new byte[512];
imageStream.Seek(-512, SeekOrigin.End);
imageStream.Read(footer, 0, 512);
}
else
{
footer = new byte[511];
imageStream.Seek(-511, SeekOrigin.End);
imageStream.Read(footer, 0, 511);
}
BigEndianBitConverter.IsLittleEndian = BitConverter.IsLittleEndian;
uint headerChecksum = BigEndianBitConverter.ToUInt32(header, 0x40);
uint footerChecksum = BigEndianBitConverter.ToUInt32(footer, 0x40);
ulong headerCookie = BigEndianBitConverter.ToUInt64(header, 0);
ulong footerCookie = BigEndianBitConverter.ToUInt64(footer, 0);
header[0x40] = 0;
header[0x41] = 0;
header[0x42] = 0;
header[0x43] = 0;
footer[0x40] = 0;
footer[0x41] = 0;
footer[0x42] = 0;
footer[0x43] = 0;
uint headerCalculatedChecksum = VhdChecksum(header);
uint footerCalculatedChecksum = VhdChecksum(footer);
DicConsole.DebugWriteLine("VirtualPC plugin", "Header checksum = 0x{0:X8}, calculated = 0x{1:X8}",
headerChecksum, headerCalculatedChecksum);
DicConsole.DebugWriteLine("VirtualPC plugin", "Header checksum = 0x{0:X8}, calculated = 0x{1:X8}",
footerChecksum, footerCalculatedChecksum);
byte[] usableHeader;
uint usableChecksum;
if(headerCookie == IMAGE_COOKIE && headerChecksum == headerCalculatedChecksum)
{
usableHeader = header;
usableChecksum = headerChecksum;
}
else if(footerCookie == IMAGE_COOKIE && footerChecksum == footerCalculatedChecksum)
{
usableHeader = footer;
usableChecksum = footerChecksum;
}
else
throw new
ImageNotSupportedException("(VirtualPC plugin): Both header and footer are corrupt, image cannot be opened.");
thisFooter = new HardDiskFooter
{
Cookie = BigEndianBitConverter.ToUInt64(usableHeader, 0x00),
Features = BigEndianBitConverter.ToUInt32(usableHeader, 0x08),
Version = BigEndianBitConverter.ToUInt32(usableHeader, 0x0C),
Offset = BigEndianBitConverter.ToUInt64(usableHeader, 0x10),
Timestamp = BigEndianBitConverter.ToUInt32(usableHeader, 0x18),
CreatorApplication = BigEndianBitConverter.ToUInt32(usableHeader, 0x1C),
CreatorVersion = BigEndianBitConverter.ToUInt32(usableHeader, 0x20),
CreatorHostOs = BigEndianBitConverter.ToUInt32(usableHeader, 0x24),
OriginalSize = BigEndianBitConverter.ToUInt64(usableHeader, 0x28),
CurrentSize = BigEndianBitConverter.ToUInt64(usableHeader, 0x30),
DiskGeometry = BigEndianBitConverter.ToUInt32(usableHeader, 0x38),
DiskType = BigEndianBitConverter.ToUInt32(usableHeader, 0x3C),
Checksum = usableChecksum,
UniqueId = BigEndianBitConverter.ToGuid(usableHeader, 0x44),
SavedState = usableHeader[0x54],
Reserved = new byte[usableHeader.Length - 0x55]
};
Array.Copy(usableHeader, 0x55, thisFooter.Reserved, 0, usableHeader.Length - 0x55);
thisDateTime = new DateTime(2000, 1, 1, 0, 0, 0, DateTimeKind.Utc);
thisDateTime = thisDateTime.AddSeconds(thisFooter.Timestamp);
Sha1Context sha1Ctx = new Sha1Context();
sha1Ctx.Update(thisFooter.Reserved);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.cookie = 0x{0:X8}", thisFooter.Cookie);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.features = 0x{0:X8}", thisFooter.Features);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.version = 0x{0:X8}", thisFooter.Version);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.offset = {0}", thisFooter.Offset);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.timestamp = 0x{0:X8} ({1})", thisFooter.Timestamp,
thisDateTime);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.creatorApplication = 0x{0:X8} (\"{1}\")",
thisFooter.CreatorApplication,
Encoding.ASCII.GetString(BigEndianBitConverter.GetBytes(thisFooter
.CreatorApplication)));
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.creatorVersion = 0x{0:X8}",
thisFooter.CreatorVersion);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.creatorHostOS = 0x{0:X8} (\"{1}\")",
thisFooter.CreatorHostOs,
Encoding.ASCII.GetString(BigEndianBitConverter
.GetBytes(thisFooter.CreatorHostOs)));
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.originalSize = {0}", thisFooter.OriginalSize);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.currentSize = {0}", thisFooter.CurrentSize);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.diskGeometry = 0x{0:X8} (C/H/S: {1}/{2}/{3})",
thisFooter.DiskGeometry, (thisFooter.DiskGeometry & 0xFFFF0000) >> 16,
(thisFooter.DiskGeometry & 0xFF00) >> 8,
thisFooter.DiskGeometry & 0xFF);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.diskType = 0x{0:X8}", thisFooter.DiskType);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.checksum = 0x{0:X8}", thisFooter.Checksum);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.uniqueId = {0}", thisFooter.UniqueId);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.savedState = 0x{0:X2}", thisFooter.SavedState);
DicConsole.DebugWriteLine("VirtualPC plugin", "footer.reserved's SHA1 = 0x{0}", sha1Ctx.End());
if(thisFooter.Version == VERSION1) imageInfo.Version = "1.0";
else
throw new
ImageNotSupportedException($"(VirtualPC plugin): Unknown image type {thisFooter.DiskType} found. Please submit a bug with an example image.");
switch(thisFooter.CreatorApplication)
{
case CREATOR_QEMU:
{
imageInfo.Application = "QEMU";
// QEMU always set same version
imageInfo.ApplicationVersion = "Unknown";
break;
}
case CREATOR_VIRTUAL_BOX:
{
imageInfo.ApplicationVersion =
$"{(thisFooter.CreatorVersion & 0xFFFF0000) >> 16}.{thisFooter.CreatorVersion & 0x0000FFFF:D2}";
switch(thisFooter.CreatorHostOs)
{
case CREATOR_MACINTOSH:
case CREATOR_MACINTOSH_OLD:
imageInfo.Application = "VirtualBox for Mac";
break;
case CREATOR_WINDOWS:
// VirtualBox uses Windows creator for any other OS
imageInfo.Application = "VirtualBox";
break;
default:
imageInfo.Application =
$"VirtualBox for unknown OS \"{Encoding.ASCII.GetString(BigEndianBitConverter.GetBytes(thisFooter.CreatorHostOs))}\"";
break;
}
break;
}
case CREATOR_VIRTUAL_SERVER:
{
imageInfo.Application = "Microsoft Virtual Server";
switch(thisFooter.CreatorVersion)
{
case VERSION_VIRTUAL_SERVER2004:
imageInfo.ApplicationVersion = "2004";
break;
default:
imageInfo.ApplicationVersion = $"Unknown version 0x{thisFooter.CreatorVersion:X8}";
break;
}
break;
}
case CREATOR_VIRTUAL_PC:
{
switch(thisFooter.CreatorHostOs)
{
case CREATOR_MACINTOSH:
case CREATOR_MACINTOSH_OLD:
switch(thisFooter.CreatorVersion)
{
case VERSION_VIRTUAL_PC_MAC:
imageInfo.Application = "Connectix Virtual PC";
imageInfo.ApplicationVersion = "5, 6 or 7";
break;
default:
imageInfo.ApplicationVersion = $"Unknown version 0x{thisFooter.CreatorVersion:X8}";
break;
}
break;
case CREATOR_WINDOWS:
switch(thisFooter.CreatorVersion)
{
case VERSION_VIRTUAL_PC_MAC:
imageInfo.Application = "Connectix Virtual PC";
imageInfo.ApplicationVersion = "5, 6 or 7";
break;
case VERSION_VIRTUAL_PC2004:
imageInfo.Application = "Microsoft Virtual PC";
imageInfo.ApplicationVersion = "2004";
break;
case VERSION_VIRTUAL_PC2007:
imageInfo.Application = "Microsoft Virtual PC";
imageInfo.ApplicationVersion = "2007";
break;
default:
imageInfo.ApplicationVersion = $"Unknown version 0x{thisFooter.CreatorVersion:X8}";
break;
}
break;
default:
imageInfo.Application =
$"Virtual PC for unknown OS \"{Encoding.ASCII.GetString(BigEndianBitConverter.GetBytes(thisFooter.CreatorHostOs))}\"";
imageInfo.ApplicationVersion = $"Unknown version 0x{thisFooter.CreatorVersion:X8}";
break;
}
break;
}
case CREATOR_DISCIMAGECHEF:
{
imageInfo.Application = "DiscImageChef";
imageInfo.ApplicationVersion =
$"{(thisFooter.CreatorVersion & 0xFF000000) >> 24}.{(thisFooter.CreatorVersion & 0xFF0000) >> 16}.{(thisFooter.CreatorVersion & 0xFF00) >> 8}.{thisFooter.CreatorVersion & 0xFF}";
}
break;
default:
{
imageInfo.Application =
$"Unknown application \"{Encoding.ASCII.GetString(BigEndianBitConverter.GetBytes(thisFooter.CreatorHostOs))}\"";
imageInfo.ApplicationVersion = $"Unknown version 0x{thisFooter.CreatorVersion:X8}";
break;
}
}
thisFilter = imageFilter;
imageInfo.ImageSize = thisFooter.CurrentSize;
imageInfo.Sectors = thisFooter.CurrentSize / 512;
imageInfo.SectorSize = 512;
imageInfo.CreationTime = imageFilter.GetCreationTime();
imageInfo.LastModificationTime = thisDateTime;
imageInfo.MediaTitle = Path.GetFileNameWithoutExtension(imageFilter.GetFilename());
imageInfo.Cylinders = (thisFooter.DiskGeometry & 0xFFFF0000) >> 16;
imageInfo.Heads = (thisFooter.DiskGeometry & 0xFF00) >> 8;
imageInfo.SectorsPerTrack = thisFooter.DiskGeometry & 0xFF;
if(thisFooter.DiskType == TYPE_DYNAMIC || thisFooter.DiskType == TYPE_DIFFERENCING)
{
imageStream.Seek((long)thisFooter.Offset, SeekOrigin.Begin);
byte[] dynamicBytes = new byte[1024];
imageStream.Read(dynamicBytes, 0, 1024);
uint dynamicChecksum = BigEndianBitConverter.ToUInt32(dynamicBytes, 0x24);
dynamicBytes[0x24] = 0;
dynamicBytes[0x25] = 0;
dynamicBytes[0x26] = 0;
dynamicBytes[0x27] = 0;
uint dynamicChecksumCalculated = VhdChecksum(dynamicBytes);
DicConsole.DebugWriteLine("VirtualPC plugin",
"Dynamic header checksum = 0x{0:X8}, calculated = 0x{1:X8}", dynamicChecksum,
dynamicChecksumCalculated);
if(dynamicChecksum != dynamicChecksumCalculated)
throw new
ImageNotSupportedException("(VirtualPC plugin): Both header and footer are corrupt, image cannot be opened.");
thisDynamic =
new DynamicDiskHeader {LocatorEntries = new ParentLocatorEntry[8], Reserved2 = new byte[256]};
for(int i = 0; i < 8; i++) thisDynamic.LocatorEntries[i] = new ParentLocatorEntry();
thisDynamic.Cookie = BigEndianBitConverter.ToUInt64(dynamicBytes, 0x00);
thisDynamic.DataOffset = BigEndianBitConverter.ToUInt64(dynamicBytes, 0x08);
thisDynamic.TableOffset = BigEndianBitConverter.ToUInt64(dynamicBytes, 0x10);
thisDynamic.HeaderVersion = BigEndianBitConverter.ToUInt32(dynamicBytes, 0x18);
thisDynamic.MaxTableEntries = BigEndianBitConverter.ToUInt32(dynamicBytes, 0x1C);
thisDynamic.BlockSize = BigEndianBitConverter.ToUInt32(dynamicBytes, 0x20);
thisDynamic.Checksum = dynamicChecksum;
thisDynamic.ParentId = BigEndianBitConverter.ToGuid(dynamicBytes, 0x28);
thisDynamic.ParentTimestamp = BigEndianBitConverter.ToUInt32(dynamicBytes, 0x38);
thisDynamic.Reserved = BigEndianBitConverter.ToUInt32(dynamicBytes, 0x3C);
thisDynamic.ParentName = Encoding.BigEndianUnicode.GetString(dynamicBytes, 0x40, 512);
for(int i = 0; i < 8; i++)
{
thisDynamic.LocatorEntries[i].PlatformCode =
BigEndianBitConverter.ToUInt32(dynamicBytes, 0x240 + 0x00 + 24 * i);
thisDynamic.LocatorEntries[i].PlatformDataSpace =
BigEndianBitConverter.ToUInt32(dynamicBytes, 0x240 + 0x04 + 24 * i);
thisDynamic.LocatorEntries[i].PlatformDataLength =
BigEndianBitConverter.ToUInt32(dynamicBytes, 0x240 + 0x08 + 24 * i);
thisDynamic.LocatorEntries[i].Reserved =
BigEndianBitConverter.ToUInt32(dynamicBytes, 0x240 + 0x0C + 24 * i);
thisDynamic.LocatorEntries[i].PlatformDataOffset =
BigEndianBitConverter.ToUInt64(dynamicBytes, 0x240 + 0x10 + 24 * i);
}
Array.Copy(dynamicBytes, 0x300, thisDynamic.Reserved2, 0, 256);
parentDateTime = new DateTime(2000, 1, 1, 0, 0, 0, DateTimeKind.Utc);
parentDateTime = parentDateTime.AddSeconds(thisDynamic.ParentTimestamp);
sha1Ctx = new Sha1Context();
sha1Ctx.Update(thisDynamic.Reserved2);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.cookie = 0x{0:X8}", thisDynamic.Cookie);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.dataOffset = {0}", thisDynamic.DataOffset);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.tableOffset = {0}", thisDynamic.TableOffset);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.headerVersion = 0x{0:X8}",
thisDynamic.HeaderVersion);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.maxTableEntries = {0}",
thisDynamic.MaxTableEntries);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.blockSize = {0}", thisDynamic.BlockSize);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.checksum = 0x{0:X8}", thisDynamic.Checksum);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.parentID = {0}", thisDynamic.ParentId);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.parentTimestamp = 0x{0:X8} ({1})",
thisDynamic.ParentTimestamp, parentDateTime);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.reserved = 0x{0:X8}", thisDynamic.Reserved);
for(int i = 0; i < 8; i++)
{
DicConsole.DebugWriteLine("VirtualPC plugin",
"dynamic.locatorEntries[{0}].platformCode = 0x{1:X8} (\"{2}\")", i,
thisDynamic.LocatorEntries[i].PlatformCode,
Encoding.ASCII.GetString(BigEndianBitConverter.GetBytes(thisDynamic
.LocatorEntries[i]
.PlatformCode)));
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.locatorEntries[{0}].platformDataSpace = {1}",
i, thisDynamic.LocatorEntries[i].PlatformDataSpace);
DicConsole.DebugWriteLine("VirtualPC plugin",
"dynamic.locatorEntries[{0}].platformDataLength = {1}", i,
thisDynamic.LocatorEntries[i].PlatformDataLength);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.locatorEntries[{0}].reserved = 0x{1:X8}", i,
thisDynamic.LocatorEntries[i].Reserved);
DicConsole.DebugWriteLine("VirtualPC plugin",
"dynamic.locatorEntries[{0}].platformDataOffset = {1}", i,
thisDynamic.LocatorEntries[i].PlatformDataOffset);
}
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.parentName = \"{0}\"",
thisDynamic.ParentName);
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.reserved2's SHA1 = 0x{0}", sha1Ctx.End());
if(thisDynamic.HeaderVersion != VERSION1)
throw new
ImageNotSupportedException($"(VirtualPC plugin): Unknown image type {thisFooter.DiskType} found. Please submit a bug with an example image.");
DateTime startTime = DateTime.UtcNow;
blockAllocationTable = new uint[thisDynamic.MaxTableEntries];
// Safe and slow code. It takes 76,572 ms to fill a 30720 entries BAT
/*
byte[] bat = new byte[thisDynamic.maxTableEntries * 4];
imageStream.Seek((long)thisDynamic.tableOffset, SeekOrigin.Begin);
imageStream.Read(bat, 0, (int)(thisDynamic.maxTableEntries * 4));
for (int i = 0; i < thisDynamic.maxTableEntries; i++)
blockAllocationTable[i] = BigEndianBitConverter.ToUInt32(bat, 4 * i);
DateTime endTime = DateTime.UtcNow;
DicConsole.DebugWriteLine("VirtualPC plugin", "Filling the BAT took {0} seconds", (endTime-startTime).TotalSeconds);
*/
// How many sectors uses the BAT
uint batSectorCount = (uint)Math.Ceiling((double)thisDynamic.MaxTableEntries * 4 / 512);
byte[] batSectorBytes = new byte[512];
// Unsafe and fast code. It takes 4 ms to fill a 30720 entries BAT
for(int i = 0; i < batSectorCount; i++)
{
imageStream.Seek((long)thisDynamic.TableOffset + i * 512, SeekOrigin.Begin);
imageStream.Read(batSectorBytes, 0, 512);
// This does the big-endian trick but reverses the order of elements also
Array.Reverse(batSectorBytes);
BatSector batSector = Marshal.ByteArrayToStructureLittleEndian<BatSector>(batSectorBytes);
// This restores the order of elements
Array.Reverse(batSector.blockPointer);
if(blockAllocationTable.Length >= i * 512 / 4 + 512 / 4)
Array.Copy(batSector.blockPointer, 0, blockAllocationTable, i * 512 / 4, 512 / 4);
else
Array.Copy(batSector.blockPointer, 0, blockAllocationTable, i * 512 / 4,
blockAllocationTable.Length - i * 512 / 4);
}
DateTime endTime = DateTime.UtcNow;
DicConsole.DebugWriteLine("VirtualPC plugin", "Filling the BAT took {0} seconds",
(endTime - startTime).TotalSeconds);
// Too noisy
/*
for (int i = 0; i < thisDynamic.maxTableEntries; i++)
DicConsole.DebugWriteLine("VirtualPC plugin", "blockAllocationTable[{0}] = {1}", i, blockAllocationTable[i]);
*/
// Get the roundest number of sectors needed to store the block bitmap
bitmapSize = (uint)Math.Ceiling((double)thisDynamic.BlockSize / 512
// 1 bit per sector on the bitmap
/ 8
// and aligned to 512 byte boundary
/ 512);
DicConsole.DebugWriteLine("VirtualPC plugin", "Bitmap is {0} sectors", bitmapSize);
}
imageInfo.XmlMediaType = XmlMediaType.BlockMedia;
switch(thisFooter.DiskType)
{
case TYPE_FIXED:
case TYPE_DYNAMIC:
{
// Nothing to do here, really.
return true;
}
case TYPE_DIFFERENCING:
{
locatorEntriesData = new byte[8][];
for(int i = 0; i < 8; i++)
if(thisDynamic.LocatorEntries[i].PlatformCode != 0x00000000)
{
locatorEntriesData[i] = new byte[thisDynamic.LocatorEntries[i].PlatformDataLength];
imageStream.Seek((long)thisDynamic.LocatorEntries[i].PlatformDataOffset, SeekOrigin.Begin);
imageStream.Read(locatorEntriesData[i], 0,
(int)thisDynamic.LocatorEntries[i].PlatformDataLength);
switch(thisDynamic.LocatorEntries[i].PlatformCode)
{
case PLATFORM_CODE_WINDOWS_ABSOLUTE:
case PLATFORM_CODE_WINDOWS_RELATIVE:
DicConsole.DebugWriteLine("VirtualPC plugin",
"dynamic.locatorEntries[{0}] = \"{1}\"", i,
Encoding.ASCII.GetString(locatorEntriesData[i]));
break;
case PLATFORM_CODE_WINDOWS_ABSOLUTE_U:
case PLATFORM_CODE_WINDOWS_RELATIVE_U:
DicConsole.DebugWriteLine("VirtualPC plugin",
"dynamic.locatorEntries[{0}] = \"{1}\"", i,
Encoding.BigEndianUnicode
.GetString(locatorEntriesData[i]));
break;
case PLATFORM_CODE_MACINTOSH_URI:
DicConsole.DebugWriteLine("VirtualPC plugin",
"dynamic.locatorEntries[{0}] = \"{1}\"", i,
Encoding.UTF8.GetString(locatorEntriesData[i]));
break;
default:
DicConsole.DebugWriteLine("VirtualPC plugin", "dynamic.locatorEntries[{0}] =", i);
PrintHex.PrintHexArray(locatorEntriesData[i], 64);
break;
}
}
int currentLocator = 0;
bool locatorFound = false;
string parentPath = null;
while(!locatorFound && currentLocator < 8)
{
switch(thisDynamic.LocatorEntries[currentLocator].PlatformCode)
{
case PLATFORM_CODE_WINDOWS_ABSOLUTE:
case PLATFORM_CODE_WINDOWS_RELATIVE:
parentPath = Encoding.ASCII.GetString(locatorEntriesData[currentLocator]);
break;
case PLATFORM_CODE_WINDOWS_ABSOLUTE_U:
case PLATFORM_CODE_WINDOWS_RELATIVE_U:
parentPath = Encoding.BigEndianUnicode.GetString(locatorEntriesData[currentLocator]);
break;
case PLATFORM_CODE_MACINTOSH_URI:
parentPath =
Uri.UnescapeDataString(Encoding.UTF8.GetString(locatorEntriesData[currentLocator]));
if(parentPath.StartsWith("file://localhost", StringComparison.InvariantCulture))
parentPath = parentPath.Remove(0, 16);
else
{
DicConsole.DebugWriteLine("VirtualPC plugin",
"Unsupported protocol classified found in URI parent path: \"{0}\"",
parentPath);
parentPath = null;
}
break;
}
if(parentPath != null)
{
DicConsole.DebugWriteLine("VirtualPC plugin", "Possible parent path: \"{0}\"", parentPath);
IFilter parentFilter =
new FiltersList().GetFilter(Path.Combine(imageFilter.GetParentFolder(), parentPath));
if(parentFilter != null) locatorFound = true;
if(!locatorFound) parentPath = null;
}
currentLocator++;
}
if(!locatorFound)
throw new
FileNotFoundException("(VirtualPC plugin): Cannot find parent file for differencing disk image");
{
parentImage = new Vhd();
IFilter parentFilter =
new FiltersList().GetFilter(Path.Combine(imageFilter.GetParentFolder(), parentPath));
if(parentFilter == null)
throw new ImageNotSupportedException("(VirtualPC plugin): Cannot find parent image filter");
/* PluginBase plugins = new PluginBase();
plugins.RegisterAllPlugins();
if (!plugins.ImagePluginsList.TryGetValue(Name.ToLower(), out parentImage))
throw new SystemException("(VirtualPC plugin): Unable to open myself");*/
if(!parentImage.Identify(parentFilter))
throw new
ImageNotSupportedException("(VirtualPC plugin): Parent image is not a Virtual PC disk image");
if(!parentImage.Open(parentFilter))
throw new ImageNotSupportedException("(VirtualPC plugin): Cannot open parent disk image");
// While specification says that parent and child disk images should contain UUID relationship
// in reality it seems that old differencing disk images stored a parent UUID that, nonetheless
// the parent never stored itself. So the only real way to know that images are related is
// because the parent IS found and SAME SIZE. Ugly...
// More funny even, tested parent images show an empty host OS, and child images a correct one.
if(parentImage.Info.Sectors != imageInfo.Sectors)
throw new
ImageNotSupportedException("(VirtualPC plugin): Parent image is of different size");
}
return true;
}
case TYPE_DEPRECATED1:
case TYPE_DEPRECATED2:
case TYPE_DEPRECATED3:
{
throw new
ImageNotSupportedException("(VirtualPC plugin): Deprecated image type found. Please submit a bug with an example image.");
}
default:
{
throw new
ImageNotSupportedException($"(VirtualPC plugin): Unknown image type {thisFooter.DiskType} found. Please submit a bug with an example image.");
}
}
}
public byte[] ReadSector(ulong sectorAddress)
{
switch(thisFooter.DiskType)
{
case TYPE_DIFFERENCING:
{
// Block number for BAT searching
uint blockNumber = (uint)Math.Floor(sectorAddress / (thisDynamic.BlockSize / 512.0));
// Sector number inside of block
uint sectorInBlock = (uint)(sectorAddress % (thisDynamic.BlockSize / 512));
if(blockAllocationTable[blockNumber] == 0xFFFFFFFF) return new byte[512];
byte[] bitmap = new byte[bitmapSize * 512];
// Offset of block in file
uint blockOffset = blockAllocationTable[blockNumber] * 512;
int bitmapByte = (int)Math.Floor((double)sectorInBlock / 8);
int bitmapBit = (int)(sectorInBlock % 8);
Stream thisStream = thisFilter.GetDataForkStream();
thisStream.Seek(blockOffset, SeekOrigin.Begin);
thisStream.Read(bitmap, 0, (int)bitmapSize * 512);
byte mask = (byte)(1 << (7 - bitmapBit));
bool dirty = (bitmap[bitmapByte] & mask) == mask;
/*
DicConsole.DebugWriteLine("VirtualPC plugin", "bitmapSize = {0}", bitmapSize);
DicConsole.DebugWriteLine("VirtualPC plugin", "blockNumber = {0}", blockNumber);
DicConsole.DebugWriteLine("VirtualPC plugin", "sectorInBlock = {0}", sectorInBlock);
DicConsole.DebugWriteLine("VirtualPC plugin", "blockOffset = {0}", blockOffset);
DicConsole.DebugWriteLine("VirtualPC plugin", "bitmapByte = {0}", bitmapByte);
DicConsole.DebugWriteLine("VirtualPC plugin", "bitmapBit = {0}", bitmapBit);
DicConsole.DebugWriteLine("VirtualPC plugin", "mask = 0x{0:X2}", mask);
DicConsole.DebugWriteLine("VirtualPC plugin", "dirty = 0x{0}", dirty);
DicConsole.DebugWriteLine("VirtualPC plugin", "bitmap = ");
PrintHex.PrintHexArray(bitmap, 64);
*/
// Sector has been written, read from child image
if(!dirty) return parentImage.ReadSector(sectorAddress);
/* Too noisy
DicConsole.DebugWriteLine("VirtualPC plugin", "Sector {0} is dirty", sectorAddress);
*/
byte[] data = new byte[512];
uint sectorOffset = blockAllocationTable[blockNumber] + bitmapSize + sectorInBlock;
thisStream = thisFilter.GetDataForkStream();
thisStream.Seek(sectorOffset * 512, SeekOrigin.Begin);
thisStream.Read(data, 0, 512);
return data;
/* Too noisy
DicConsole.DebugWriteLine("VirtualPC plugin", "Sector {0} is clean", sectorAddress);
*/
// Read sector from parent image
}
default: return ReadSectors(sectorAddress, 1);
}
}
public byte[] ReadSectors(ulong sectorAddress, uint length)
{
switch(thisFooter.DiskType)
{
case TYPE_FIXED:
{
byte[] data = new byte[512 * length];
Stream thisStream = thisFilter.GetDataForkStream();
thisStream.Seek((long)(sectorAddress * 512), SeekOrigin.Begin);
thisStream.Read(data, 0, (int)(512 * length));
return data;
}
// Contrary to Microsoft's specifications that tell us to check the bitmap
// and in case of unused sector just return zeros, as blocks are allocated
// as a whole, this would waste time and miss cache, so we read any sector
// as long as it is in the block.
case TYPE_DYNAMIC:
{
// Block number for BAT searching
uint blockNumber = (uint)Math.Floor(sectorAddress / (thisDynamic.BlockSize / 512.0));
// Sector number inside of block
uint sectorInBlock = (uint)(sectorAddress % (thisDynamic.BlockSize / 512));
// How many sectors before reaching end of block
uint remainingInBlock = thisDynamic.BlockSize / 512 - sectorInBlock;
// Data that needs to be read from another block
byte[] suffix = null;
// How many sectors to read from this block
uint sectorsToReadHere;
// Asked to read more sectors than are remaining in block
if(length > remainingInBlock)
{
suffix = ReadSectors(sectorAddress + remainingInBlock, length - remainingInBlock);
sectorsToReadHere = remainingInBlock;
}
else sectorsToReadHere = length;
// Offset of sector in file
uint sectorOffset = blockAllocationTable[blockNumber] + bitmapSize + sectorInBlock;
// Data that can be read in this block
byte[] prefix = new byte[sectorsToReadHere * 512];
// 0xFFFFFFFF means unallocated
if(blockAllocationTable[blockNumber] != 0xFFFFFFFF)
{
Stream thisStream = thisFilter.GetDataForkStream();
thisStream.Seek(sectorOffset * 512, SeekOrigin.Begin);
thisStream.Read(prefix, 0, (int)(512 * sectorsToReadHere));
}
// If it is unallocated, just fill with zeroes
else Array.Clear(prefix, 0, prefix.Length);
// If we needed to read from another block, join all the data
if(suffix == null) return prefix;
byte[] data = new byte[512 * length];
Array.Copy(prefix, 0, data, 0, prefix.Length);
Array.Copy(suffix, 0, data, prefix.Length, suffix.Length);
return data;
}
case TYPE_DIFFERENCING:
{
// As on differencing images, each independent sector can be read from child or parent
// image, we must read sector one by one
byte[] fullData = new byte[512 * length];
for(ulong i = 0; i < length; i++)
{
byte[] oneSector = ReadSector(sectorAddress + i);
Array.Copy(oneSector, 0, fullData, (int)(i * 512), 512);
}
return fullData;
}
case TYPE_DEPRECATED1:
case TYPE_DEPRECATED2:
case TYPE_DEPRECATED3:
{
throw new
ImageNotSupportedException("(VirtualPC plugin): Deprecated image type found. Please submit a bug with an example image.");
}
default:
{
throw new
ImageNotSupportedException($"(VirtualPC plugin): Unknown image type {thisFooter.DiskType} found. Please submit a bug with an example image.");
}
}
}
}
}
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