private void ReadHeaders()
{
long pos = _footer.DataOffset;
while (pos != -1)
{
_fileStream.Position = pos;
Header hdr = Header.FromStream(_fileStream);
if (hdr.Cookie == DynamicHeader.HeaderCookie)
{
_fileStream.Position = pos;
_dynamicHeader = DynamicHeader.FromStream(_fileStream);
if (!_dynamicHeader.IsValid())
{
throw new IOException("Invalid Dynamic Disc Header");
}
}
pos = hdr.DataOffset;
}
}
private void CheckDynamicHeader()
{
long lastHeaderEnd = _footer.DataOffset + 512;
long pos = _footer.DataOffset;
while (pos != -1)
{
if ((pos % 512) != 0)
{
ReportError("DynHeader: Unaligned header @{0}", pos);
}
_fileStream.Position = pos;
Header hdr = Header.FromStream(_fileStream);
if (hdr.Cookie == DynamicHeader.HeaderCookie)
{
if (_dynamicHeader != null)
{
ReportError("DynHeader: Duplicate dynamic header found");
}
_fileStream.Position = pos;
_dynamicHeader = DynamicHeader.FromStream(_fileStream);
if (pos + 1024 > lastHeaderEnd)
{
lastHeaderEnd = pos + 1024;
}
}
else
{
ReportWarning("DynHeader: Undocumented header found, with cookie '" + hdr.Cookie + "'");
if (pos + 512 > lastHeaderEnd)
{
lastHeaderEnd = pos + 1024;
}
}
pos = hdr.DataOffset;
}
if (_dynamicHeader == null)
{
ReportError("DynHeader: No dynamic header found");
return;
}
if (_dynamicHeader.TableOffset < lastHeaderEnd)
{
ReportError("DynHeader: BAT offset is before last header");
}
if ((_dynamicHeader.TableOffset % 512) != 0)
{
ReportError("DynHeader: BAT offset is not sector aligned");
}
if (_dynamicHeader.HeaderVersion != 0x00010000)
{
ReportError("DynHeader: Unrecognized header version");
}
if (_dynamicHeader.MaxTableEntries != Utilities.Ceil(_footer.CurrentSize, _dynamicHeader.BlockSize))
{
ReportError("DynHeader: Max table entries is invalid");
}
if ((_dynamicHeader.BlockSize != Sizes.OneMiB * 2) && (_dynamicHeader.BlockSize != Sizes.OneKiB * 512))
{
ReportWarning("DynHeader: Using non-standard block size '" + _dynamicHeader.BlockSize + "'");
}
if (!Utilities.IsPowerOfTwo(_dynamicHeader.BlockSize))
{
ReportError("DynHeader: Block size is not a power of 2");
}
if (!_dynamicHeader.IsChecksumValid())
{
ReportError("DynHeader: Invalid checksum");
}
if (_footer.DiskType == FileType.Dynamic && _dynamicHeader.ParentUniqueId != Guid.Empty)
{
ReportWarning("DynHeader: Parent Id is not null for dynamic disk");
}
else if (_footer.DiskType == FileType.Differencing && _dynamicHeader.ParentUniqueId == Guid.Empty)
{
ReportError("DynHeader: Parent Id is null for differencing disk");
}
if (_footer.DiskType == FileType.Differencing && _dynamicHeader.ParentTimestamp > DateTime.UtcNow)
{
ReportWarning("DynHeader: Parent timestamp is greater than current time");
}
}