private void LoadDescriptor(Stream s)
{
s.Position = 0;
byte[] header = Utilities.ReadFully(s, (int)Math.Min(Sizes.Sector, s.Length));
if (header.Length < Sizes.Sector || Utilities.ToUInt32LittleEndian(header, 0) != HostedSparseExtentHeader.VmdkMagicNumber)
{
s.Position = 0;
_descriptor = new DescriptorFile(s);
if (_access != FileAccess.Read)
{
_descriptor.ContentId = (uint)_rng.Next();
s.Position = 0;
_descriptor.Write(s);
s.SetLength(s.Position);
}
}
else
{
// This is a sparse disk extent, hopefully with embedded descriptor...
HostedSparseExtentHeader hdr = HostedSparseExtentHeader.Read(header, 0);
if (hdr.DescriptorOffset != 0)
{
Stream descriptorStream = new SubStream(s, hdr.DescriptorOffset * Sizes.Sector, hdr.DescriptorSize * Sizes.Sector);
_descriptor = new DescriptorFile(descriptorStream);
if (_access != FileAccess.Read)
{
_descriptor.ContentId = (uint)_rng.Next();
descriptorStream.Position = 0;
_descriptor.Write(descriptorStream);
byte[] blank = new byte[descriptorStream.Length - descriptorStream.Position];
descriptorStream.Write(blank, 0, blank.Length);
}
}
}
}
public HostedSparseExtentStream(Stream file, Ownership ownsFile, long diskOffset, SparseStream parentDiskStream, Ownership ownsParentDiskStream)
{
_fileStream = file;
_ownsFileStream = ownsFile;
_diskOffset = diskOffset;
_parentDiskStream = parentDiskStream;
_ownsParentDiskStream = ownsParentDiskStream;
file.Position = 0;
byte[] headerSector = Utilities.ReadFully(file, Sizes.Sector);
_hostedHeader = HostedSparseExtentHeader.Read(headerSector, 0);
if (_hostedHeader.GdOffset == -1)
{
// Fall back to secondary copy that (should) be at the end of the stream, just before the end-of-stream sector marker
file.Position = file.Length - Sizes.OneKiB;
headerSector = Utilities.ReadFully(file, Sizes.Sector);
_hostedHeader = HostedSparseExtentHeader.Read(headerSector, 0);
if (_hostedHeader.MagicNumber != HostedSparseExtentHeader.VmdkMagicNumber)
{
throw new IOException("Unable to locate valid VMDK header or footer");
}
}
_header = _hostedHeader;
if (_hostedHeader.CompressAlgorithm != 0 && _hostedHeader.CompressAlgorithm != 1)
{
throw new NotSupportedException("Only uncompressed and DEFLATE compressed disks supported");
}
_gtCoverage = _header.NumGTEsPerGT * _header.GrainSize * Sizes.Sector;
LoadGlobalDirectory();
}
private static void CreateSparseExtent(Stream extentStream, long size, long descriptorLength, out long descriptorStart)
{
// Figure out grain size and number of grain tables, and adjust actual extent size to be a multiple
// of grain size
const int GtesPerGt = 512;
long grainSize = 128;
int numGrainTables = (int)Utilities.Ceil(size, grainSize * GtesPerGt * Sizes.Sector);
descriptorLength = Utilities.RoundUp(descriptorLength, Sizes.Sector);
descriptorStart = 0;
if (descriptorLength != 0)
{
descriptorStart = 1;
}
long redundantGrainDirStart = Math.Max(descriptorStart, 1) + Utilities.Ceil(descriptorLength, Sizes.Sector);
long redundantGrainDirLength = numGrainTables * 4;
long redundantGrainTablesStart = redundantGrainDirStart + Utilities.Ceil(redundantGrainDirLength, Sizes.Sector);
long redundantGrainTablesLength = numGrainTables * Utilities.RoundUp(GtesPerGt * 4, Sizes.Sector);
long grainDirStart = redundantGrainTablesStart + Utilities.Ceil(redundantGrainTablesLength, Sizes.Sector);
long grainDirLength = numGrainTables * 4;
long grainTablesStart = grainDirStart + Utilities.Ceil(grainDirLength, Sizes.Sector);
long grainTablesLength = numGrainTables * Utilities.RoundUp(GtesPerGt * 4, Sizes.Sector);
long dataStart = Utilities.RoundUp(grainTablesStart + Utilities.Ceil(grainTablesLength, Sizes.Sector), grainSize);
// Generate the header, and write it
HostedSparseExtentHeader header = new HostedSparseExtentHeader();
header.Flags = HostedSparseExtentFlags.ValidLineDetectionTest | HostedSparseExtentFlags.RedundantGrainTable;
header.Capacity = Utilities.RoundUp(size, grainSize * Sizes.Sector) / Sizes.Sector;
header.GrainSize = grainSize;
header.DescriptorOffset = descriptorStart;
header.DescriptorSize = descriptorLength / Sizes.Sector;
header.NumGTEsPerGT = GtesPerGt;
header.RgdOffset = redundantGrainDirStart;
header.GdOffset = grainDirStart;
header.Overhead = dataStart;
extentStream.Position = 0;
extentStream.Write(header.GetBytes(), 0, Sizes.Sector);
// Zero-out the descriptor space
if (descriptorLength > 0)
{
byte[] descriptor = new byte[descriptorLength];
extentStream.Position = descriptorStart * Sizes.Sector;
extentStream.Write(descriptor, 0, descriptor.Length);
}
// Generate the redundant grain dir, and write it
byte[] grainDir = new byte[numGrainTables * 4];
for (int i = 0; i < numGrainTables; ++i)
{
Utilities.WriteBytesLittleEndian((uint)(redundantGrainTablesStart + (i * Utilities.Ceil(GtesPerGt * 4, Sizes.Sector))), grainDir, i * 4);
}
extentStream.Position = redundantGrainDirStart * Sizes.Sector;
extentStream.Write(grainDir, 0, grainDir.Length);
// Write out the blank grain tables
byte[] grainTable = new byte[GtesPerGt * 4];
for (int i = 0; i < numGrainTables; ++i)
{
extentStream.Position = (redundantGrainTablesStart * Sizes.Sector) + (i * Utilities.RoundUp(GtesPerGt * 4, Sizes.Sector));
extentStream.Write(grainTable, 0, grainTable.Length);
}
// Generate the main grain dir, and write it
for (int i = 0; i < numGrainTables; ++i)
{
Utilities.WriteBytesLittleEndian((uint)(grainTablesStart + (i * Utilities.Ceil(GtesPerGt * 4, Sizes.Sector))), grainDir, i * 4);
}
extentStream.Position = grainDirStart * Sizes.Sector;
extentStream.Write(grainDir, 0, grainDir.Length);
// Write out the blank grain tables
for (int i = 0; i < numGrainTables; ++i)
{
extentStream.Position = (grainTablesStart * Sizes.Sector) + (i * Utilities.RoundUp(GtesPerGt * 4, Sizes.Sector));
extentStream.Write(grainTable, 0, grainTable.Length);
}
// Make sure stream is correct length
if (extentStream.Length != dataStart * Sizes.Sector)
{
extentStream.SetLength(dataStart * Sizes.Sector);
}
}