/// <summary>
/// Reads the volume descriptors for
/// </summary>
/// <param name="extentVds">The anchor volume extent information.</param>
/// <returns>Returns true if the volume descriptors were read from the image successfully.</returns>
private bool ReadVolumeDescriptors(UdfFileExtent extentVds)
{
byte[] buffer = new byte[SectorSize];
long location = extentVds.Position;
while (location < extentVds.Length && location < this.imageSize)
{
this.stream.Seek(location << SectorSizeLog, (int)SeekOrigin.Begin, IntPtr.Zero);
if (!this.stream.ReadSafe(buffer, buffer.Length))
{
return(false);
}
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, buffer.Length);
switch ((VolumeDescriptorType)tag.Identifier)
{
case VolumeDescriptorType.Terminating:
// Found terminating descriptor. Image is valid.
return(true);
case VolumeDescriptorType.Partition:
if (this.Partitions.Count >= MaxPartitions)
{
return(false);
}
this.ReadPartitionDescriptor(buffer);
break;
case VolumeDescriptorType.LogicalVolume:
if (this.LogicalVolumes.Count >= MaxLogicalVolumes || !this.ReadLogicalDescriptor(buffer))
{
return(false);
}
break;
}
location++;
}
// Did not find the terminating descriptor. Not a valid image.
return(false);
}
/// <summary>
/// Reads the file and directory structure from the image.
/// </summary>
/// <returns>Returns true if the file system is valid.</returns>
private bool ReadFileStructure()
{
foreach (var volume in this.LogicalVolumes)
{
// Ensure the volume and parittion are valid.
if (!this.ValidateVolumePartition(volume))
{
return(false);
}
int volIndex = this.LogicalVolumes.IndexOf(volume);
LongAllocationDescriptor nextExtent = volume.FileSetLocation;
if (nextExtent.Length < VirtualSectorSize)
{
return(false);
}
byte[] buffer = new byte[nextExtent.Length];
this.ReadData(volIndex, nextExtent, buffer);
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, buffer.Length);
if (tag.Identifier != (int)VolumeDescriptorType.FileSet)
{
return(false);
}
UdfFileSet fs = new UdfFileSet();
fs.RecordingTime.Parse(16, buffer);
fs.RootDirICB.Parse(400, buffer);
volume.FileSet = fs;
if (!this.ReadRecord(this.RootDirectory as UdfRecord, volIndex, fs.RootDirICB, MaxRecurseLevels))
{
return(false);
}
}
return(true);
}
/// <summary>
/// Reads the Anchor Volume pointer from the image.
/// </summary>
/// <returns>Returns true if the pointer was found.</returns>
private UdfFileExtent ReadAnchorVolumePointer()
{
UdfFileExtent result = null;
byte[] buffer = new byte[SectorSize];
this.stream.Seek(-buffer.Length, (int)SeekOrigin.End, IntPtr.Zero);
if (!this.stream.ReadSafe(buffer, buffer.Length))
{
return(result);
}
VolumeTag tag = new VolumeTag();
if (tag.Parse(0, buffer, buffer.Length) &&
tag.Identifier == (short)VolumeDescriptorType.AnchorVolumePtr)
{
result = new UdfFileExtent();
result.Parse(16, buffer);
}
return(result);
}
/// <summary>
/// Reads the data from the image for a record.
/// </summary>
/// <param name="item">The item to read the data into.</param>
/// <param name="volumeIndex">The index of the volume the file resides on.</param>
/// <param name="lad">The long allocation descriptor of the file.</param>
/// <param name="numRecurseAllowed">The number of recursions allowed before the method fails.</param>
/// <returns>Returns true if the record was read successfully.</returns>
private bool ReadRecordData(UdfRecord item, int volumeIndex, LongAllocationDescriptor lad, int numRecurseAllowed)
{
if (this.itemCount > MaxItems)
{
return(false);
}
LogicalVolume volume = this.LogicalVolumes[volumeIndex];
if (lad.Length != volume.BlockSize)
{
return(false);
}
// Read the record.
int size = lad.Length;
byte[] buffer = new byte[size];
if (!this.ReadData(volumeIndex, lad, buffer))
{
return(false);
}
// Validate the tag is a file.
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, size);
if (tag.Identifier != (short)VolumeDescriptorType.File)
{
return(false);
}
// Validate the IcbTage indicates file or directory.
item.IcbTag.Parse(16, buffer);
if (item.IcbTag.FileType != IcbFileType.Directory && item.IcbTag.FileType != IcbFileType.File)
{
return(false);
}
item.Parse(buffer);
int extendedAttrLen = UdfHelper.Get32(168, buffer);
int allocDescriptorsLen = UdfHelper.Get32(172, buffer);
if ((extendedAttrLen & 3) != 0)
{
return(false);
}
int position = 176;
if (extendedAttrLen > size - position)
{
return(false);
}
position += extendedAttrLen;
IcbDescriptorType desctType = item.IcbTag.DescriptorType;
if (allocDescriptorsLen > size - position)
{
return(false);
}
if (desctType == IcbDescriptorType.Inline)
{
// If the file data is inline, read it in now since we have it.
item.IsInline = true;
item.InlineData = UdfHelper.Readbytes(position, buffer, allocDescriptorsLen);
}
else
{
// Otherwise read the information about where the file is located for later.
item.IsInline = false;
item.InlineData = new byte[0];
if ((desctType != IcbDescriptorType.Short) && (desctType != IcbDescriptorType.Long))
{
return(false);
}
for (int index = 0; index < allocDescriptorsLen;)
{
FileExtent extent = new FileExtent();
if (desctType == IcbDescriptorType.Short)
{
if (index + 8 > allocDescriptorsLen)
{
return(false);
}
ShortAllocationDescriptor sad = new ShortAllocationDescriptor();
sad.Parse(position + index, buffer);
extent.Position = sad.Position;
extent.Length = sad.Length;
extent.PartitionReference = lad.Location.PartitionReference;
index += 8;
}
else
{
if (index + 16 > allocDescriptorsLen)
{
return(false);
}
LongAllocationDescriptor ladNew = new LongAllocationDescriptor();
ladNew.Parse(position + index, buffer);
extent.Position = ladNew.Location.Position;
extent.PartitionReference = ladNew.Location.PartitionReference;
extent.Length = ladNew.Length;
index += 16;
}
item.Extents.Add(extent);
}
}
if (item.IcbTag.IsDirectory)
{
if (!item.CheckChunkSizes() || !this.CheckItemExtents(volumeIndex, item))
{
return(false);
}
buffer = new byte[0];
if (!this.ReadFromFile(volumeIndex, ref item, ref buffer))
{
return(false);
}
item._size = 0;
item.Extents.Clear();
size = buffer.Length;
int processedTotal = 0;
int processedCur = -1;
while (processedTotal < size || processedCur == 0)
{
UdfFileInformation fileId = new UdfFileInformation();
fileId.Parse(processedTotal, buffer, (size - processedTotal), ref processedCur);
if (!fileId.IsItLinkParent)
{
// Recursively read the contentst of the drirectory
UdfRecord fileItem = new UdfRecord();
fileItem.Id = fileId.Identifier;
if (fileItem.Id.Data != null)
{
this.fileNameLengthTotal += fileItem.Id.Data.Length;
}
if (this.fileNameLengthTotal > MaxFileNameLength)
{
return(false);
}
fileItem._Parent = item;
item.Subitems.Add(fileItem);
if (item.Subitems.Count > MaxFiles)
{
return(false);
}
this.ReadRecord(fileItem, volumeIndex, fileId.Icb, numRecurseAllowed);
}
processedTotal += processedCur;
}
}
else
{
if (item.Extents.Count > MaxExtents - this.numExtents)
{
return(false);
}
this.numExtents += item.Extents.Count;
if (item.InlineData.Length > MaxInlineExtentsSize - this.inlineExtentsSize)
{
return(false);
}
this.inlineExtentsSize += item.InlineData.Length;
}
this.itemCount++;
return(true);
}
/// <summary>
/// Reads the volume descriptors for
/// </summary>
/// <param name="extentVds">The anchor volume extent information.</param>
/// <returns>Returns true if the volume descriptors were read from the image successfully.</returns>
private bool ReadVolumeDescriptors(UdfFileExtent extentVds)
{
byte[] buffer = new byte[SectorSize];
long location = extentVds.Position;
while (location < extentVds.Length && location < this.imageSize)
{
this.stream.Seek(location << SectorSizeLog, (int)SeekOrigin.Begin, IntPtr.Zero);
if (!this.stream.ReadSafe(buffer, buffer.Length))
{
return false;
}
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, buffer.Length);
switch ((VolumeDescriptorType)tag.Identifier)
{
case VolumeDescriptorType.Terminating:
// Found terminating descriptor. Image is valid.
return true;
case VolumeDescriptorType.Partition:
if (this.Partitions.Count >= MaxPartitions)
{
return false;
}
this.ReadPartitionDescriptor(buffer);
break;
case VolumeDescriptorType.LogicalVolume:
if (this.LogicalVolumes.Count >= MaxLogicalVolumes || !this.ReadLogicalDescriptor(buffer))
{
return false;
}
break;
}
location++;
}
// Did not find the terminating descriptor. Not a valid image.
return false;
}
/// <summary>
/// Reads the data from the image for a record.
/// </summary>
/// <param name="item">The item to read the data into.</param>
/// <param name="volumeIndex">The index of the volume the file resides on.</param>
/// <param name="lad">The long allocation descriptor of the file.</param>
/// <param name="numRecurseAllowed">The number of recursions allowed before the method fails.</param>
/// <returns>Returns true if the record was read successfully.</returns>
private bool ReadRecordData(UdfRecord item, int volumeIndex, LongAllocationDescriptor lad, int numRecurseAllowed)
{
if (this.itemCount > MaxItems)
{
return false;
}
LogicalVolume volume = this.LogicalVolumes[volumeIndex];
if (lad.Length != volume.BlockSize)
{
return false;
}
// Read the record.
int size = lad.Length;
byte[] buffer = new byte[size];
if (!this.ReadData(volumeIndex, lad, buffer))
{
return false;
}
// Validate the tag is a file.
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, size);
if (tag.Identifier != (short)VolumeDescriptorType.File)
{
return false;
}
// Validate the IcbTage indicates file or directory.
item.IcbTag.Parse(16, buffer);
if (item.IcbTag.FileType != IcbFileType.Directory && item.IcbTag.FileType != IcbFileType.File)
{
return false;
}
item.Parse(buffer);
int extendedAttrLen = UdfHelper.Get32(168, buffer);
int allocDescriptorsLen = UdfHelper.Get32(172, buffer);
if ((extendedAttrLen & 3) != 0)
{
return false;
}
int position = 176;
if (extendedAttrLen > size - position)
{
return false;
}
position += extendedAttrLen;
IcbDescriptorType desctType = item.IcbTag.DescriptorType;
if (allocDescriptorsLen > size - position)
{
return false;
}
if (desctType == IcbDescriptorType.Inline)
{
// If the file data is inline, read it in now since we have it.
item.IsInline = true;
item.InlineData = UdfHelper.Readbytes(position, buffer, allocDescriptorsLen);
}
else
{
// Otherwise read the information about where the file is located for later.
item.IsInline = false;
item.InlineData = new byte[0];
if ((desctType != IcbDescriptorType.Short) && (desctType != IcbDescriptorType.Long))
{
return false;
}
for (int index = 0; index < allocDescriptorsLen;)
{
FileExtent extent = new FileExtent();
if (desctType == IcbDescriptorType.Short)
{
if (index + 8 > allocDescriptorsLen)
{
return false;
}
ShortAllocationDescriptor sad = new ShortAllocationDescriptor();
sad.Parse(position + index, buffer);
extent.Position = sad.Position;
extent.Length = sad.Length;
extent.PartitionReference = lad.Location.PartitionReference;
index += 8;
}
else
{
if (index + 16 > allocDescriptorsLen)
{
return false;
}
LongAllocationDescriptor ladNew = new LongAllocationDescriptor();
ladNew.Parse(position + index, buffer);
extent.Position = ladNew.Location.Position;
extent.PartitionReference = ladNew.Location.PartitionReference;
extent.Length = ladNew.Length;
index += 16;
}
item.Extents.Add(extent);
}
}
if (item.IcbTag.IsDirectory)
{
if (!item.CheckChunkSizes() || !this.CheckItemExtents(volumeIndex, item))
{
return false;
}
buffer = new byte[0];
if (!this.ReadFromFile(volumeIndex, ref item, ref buffer))
{
return false;
}
item._size = 0;
item.Extents.Clear();
size = buffer.Length;
int processedTotal = 0;
int processedCur = -1;
while (processedTotal < size || processedCur == 0)
{
UdfFileInformation fileId = new UdfFileInformation();
fileId.Parse(processedTotal, buffer, (size - processedTotal), ref processedCur);
if (!fileId.IsItLinkParent)
{
// Recursively read the contentst of the drirectory
UdfRecord fileItem = new UdfRecord();
fileItem.Id = fileId.Identifier;
if (fileItem.Id.Data != null)
{
this.fileNameLengthTotal += fileItem.Id.Data.Length;
}
if (this.fileNameLengthTotal > MaxFileNameLength)
{
return false;
}
fileItem._Parent = item;
item.Subitems.Add(fileItem);
if (item.Subitems.Count > MaxFiles)
{
return false;
}
this.ReadRecord(fileItem, volumeIndex, fileId.Icb, numRecurseAllowed);
}
processedTotal += processedCur;
}
}
else
{
if (item.Extents.Count > MaxExtents - this.numExtents)
{
return false;
}
this.numExtents += item.Extents.Count;
if (item.InlineData.Length > MaxInlineExtentsSize - this.inlineExtentsSize)
{
return false;
}
this.inlineExtentsSize += item.InlineData.Length;
}
this.itemCount++;
return true;
}
/// <summary>
/// Reads the file and directory structure from the image.
/// </summary>
/// <returns>Returns true if the file system is valid.</returns>
private bool ReadFileStructure()
{
foreach (var volume in this.LogicalVolumes)
{
// Ensure the volume and parittion are valid.
if (!this.ValidateVolumePartition(volume))
{
return false;
}
int volIndex = this.LogicalVolumes.IndexOf(volume);
LongAllocationDescriptor nextExtent = volume.FileSetLocation;
if (nextExtent.Length < VirtualSectorSize)
{
return false;
}
byte[] buffer = new byte[nextExtent.Length];
this.ReadData(volIndex, nextExtent, buffer);
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, buffer.Length);
if (tag.Identifier != (int)VolumeDescriptorType.FileSet)
{
return false;
}
UdfFileSet fs = new UdfFileSet();
fs.RecordingTime.Parse(16, buffer);
fs.RootDirICB.Parse(400, buffer);
volume.FileSet = fs;
if (!this.ReadRecord(this.RootDirectory as UdfRecord, volIndex, fs.RootDirICB, MaxRecurseLevels))
{
return false;
}
}
return true;
}
/// <summary>
/// Reads the Anchor Volume pointer from the image.
/// </summary>
/// <returns>Returns true if the pointer was found.</returns>
private UdfFileExtent ReadAnchorVolumePointer()
{
UdfFileExtent result = null;
byte[] buffer = new byte[SectorSize];
this.stream.Seek(-buffer.Length, (int)SeekOrigin.End, IntPtr.Zero);
if (!this.stream.ReadSafe(buffer, buffer.Length))
{
return result;
}
VolumeTag tag = new VolumeTag();
if (tag.Parse(0, buffer, buffer.Length)
&& tag.Identifier == (short)VolumeDescriptorType.AnchorVolumePtr)
{
result = new UdfFileExtent();
result.Parse(16, buffer);
}
return result;
}
