Beispiel #1
0
        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();
        }
Beispiel #2
0
 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);
             }
         }
     }
 }