public File(INtfsContext context, FileRecord baseRecord)
{
_context = context;
_mft = _context.Mft;
_records = new List<FileRecord>();
_records.Add(baseRecord);
_indexCache = new ObjectCache<string, Index>();
_attributes = new List<NtfsAttribute>();
LoadAttributes();
}
public void WriteRecord(FileRecord record)
{
int recordSize = record.Size;
if (recordSize > _recordLength)
{
throw new IOException("Attempting to write over-sized MFT record");
}
byte[] buffer = new byte[_recordLength];
record.ToBytes(buffer, 0);
_recordStream.Position = record.MasterFileTableIndex * (long)_recordLength;
_recordStream.Write(buffer, 0, _recordLength);
_recordStream.Flush();
// We may have modified our own meta-data by extending the data stream, so
// make sure our records are up-to-date.
if (_self.MftRecordIsDirty)
{
DirectoryEntry dirEntry = _self.DirectoryEntry;
if (dirEntry != null)
{
dirEntry.UpdateFrom(_self);
}
_self.UpdateRecordInMft();
}
// Need to update Mirror. OpenRaw is OK because this is short duration, and we don't
// extend or otherwise modify any meta-data, just the content of the Data stream.
if (record.MasterFileTableIndex < 4 && _self.Context.GetFileByIndex != null)
{
File mftMirror = _self.Context.GetFileByIndex(MftMirrorIndex);
if (mftMirror != null)
{
using (Stream s = mftMirror.OpenStream(AttributeType.Data, null, FileAccess.ReadWrite))
{
s.Position = record.MasterFileTableIndex * (long)_recordLength;
s.Write(buffer, 0, _recordLength);
}
}
}
}
public FileRecord GetRecord(long index, bool ignoreMagic, bool ignoreBitmap)
{
if (ignoreBitmap || _bitmap == null || _bitmap.IsPresent(index))
{
FileRecord result = _recordCache[index];
if (result != null)
{
return result;
}
if ((index + 1) * _recordLength <= _recordStream.Length)
{
_recordStream.Position = index * _recordLength;
byte[] recordBuffer = Utilities.ReadFully(_recordStream, _recordLength);
result = new FileRecord(_bytesPerSector);
result.FromBytes(recordBuffer, 0, ignoreMagic);
result.LoadedIndex = (uint)index;
}
else
{
result = new FileRecord(_bytesPerSector, _recordLength, (uint)index);
}
_recordCache[index] = result;
return result;
}
return null;
}
public FileRecord AllocateRecord(long index, FileRecordFlags flags)
{
_bitmap.MarkPresent(index);
FileRecord newRecord = new FileRecord(_bytesPerSector, _recordLength, (uint)index);
_recordCache[index] = newRecord;
newRecord.Flags = FileRecordFlags.InUse | flags;
WriteRecord(newRecord);
_self.UpdateRecordInMft();
return newRecord;
}
public FileRecord AllocateRecord(FileRecordFlags flags, bool isMft)
{
long index;
if (isMft)
{
// Have to take a lot of care extending the MFT itself, to ensure we never end up unable to
// bootstrap the file system via the MFT itself - hence why special records are reserved
// for MFT's own MFT record overflow.
for (int i = 15; i > 11; --i)
{
FileRecord r = GetRecord(i, false);
if (r.BaseFile.SequenceNumber == 0)
{
r.Reset();
r.Flags |= FileRecordFlags.InUse;
WriteRecord(r);
return r;
}
}
throw new IOException("MFT too fragmented - unable to allocate MFT overflow record");
}
else
{
index = _bitmap.AllocateFirstAvailable(FirstAvailableMftIndex);
}
if (index * _recordLength >= _recordStream.Length)
{
// Note: 64 is significant, since bitmap extends by 8 bytes (=64 bits) at a time.
long newEndIndex = Utilities.RoundUp(index + 1, 64);
_recordStream.SetLength(newEndIndex * _recordLength);
for (long i = index; i < newEndIndex; ++i)
{
FileRecord record = new FileRecord(_bytesPerSector, _recordLength, (uint)i);
WriteRecord(record);
}
}
FileRecord newRecord = GetRecord(index, true);
newRecord.ReInitialize(_bytesPerSector, _recordLength, (uint)index);
_recordCache[index] = newRecord;
newRecord.Flags = FileRecordFlags.InUse | flags;
WriteRecord(newRecord);
_self.UpdateRecordInMft();
return newRecord;
}
public File InitializeNew(INtfsContext context, long firstBitmapCluster, ulong numBitmapClusters, long firstRecordsCluster, ulong numRecordsClusters)
{
BiosParameterBlock bpb = context.BiosParameterBlock;
FileRecord fileRec = new FileRecord(bpb.BytesPerSector, bpb.MftRecordSize, (uint)MftIndex);
fileRec.Flags = FileRecordFlags.InUse;
fileRec.SequenceNumber = 1;
_recordCache[MftIndex] = fileRec;
_self = new File(context, fileRec);
StandardInformation.InitializeNewFile(_self, FileAttributeFlags.Hidden | FileAttributeFlags.System);
NtfsStream recordsStream = _self.CreateStream(AttributeType.Data, null, firstRecordsCluster, numRecordsClusters, (uint)bpb.BytesPerCluster);
_recordStream = recordsStream.Open(FileAccess.ReadWrite);
Wipe(_recordStream);
NtfsStream bitmapStream = _self.CreateStream(AttributeType.Bitmap, null, firstBitmapCluster, numBitmapClusters, (uint)bpb.BytesPerCluster);
using (Stream s = bitmapStream.Open(FileAccess.ReadWrite))
{
Wipe(s);
s.SetLength(8);
_bitmap = new Bitmap(s, long.MaxValue);
}
_recordLength = context.BiosParameterBlock.MftRecordSize;
_bytesPerSector = context.BiosParameterBlock.BytesPerSector;
_bitmap.MarkPresentRange(0, 1);
// Write the MFT's own record to itself
byte[] buffer = new byte[_recordLength];
fileRec.ToBytes(buffer, 0);
_recordStream.Position = 0;
_recordStream.Write(buffer, 0, _recordLength);
_recordStream.Flush();
return _self;
}
public FileRecord GetBootstrapRecord()
{
_recordStream.Position = 0;
byte[] mftSelfRecordData = Utilities.ReadFully(_recordStream, _recordLength);
FileRecord mftSelfRecord = new FileRecord(_bytesPerSector);
mftSelfRecord.FromBytes(mftSelfRecordData, 0);
_recordCache[MftIndex] = mftSelfRecord;
return mftSelfRecord;
}
private void MoveAttribute(FileRecord record, AttributeRecord attrRec, FileRecord targetRecord)
{
AttributeReference oldRef = new AttributeReference(record.Reference, attrRec.AttributeId);
record.RemoveAttribute(attrRec.AttributeId);
targetRecord.AddAttribute(attrRec);
AttributeReference newRef = new AttributeReference(targetRecord.Reference, attrRec.AttributeId);
foreach (var attr in _attributes)
{
attr.ReplaceExtent(oldRef, newRef, attrRec);
}
UpdateAttributeList();
}
private bool ExpelAttribute(FileRecord record)
{
if (record.MasterFileTableIndex == MasterFileTable.MftIndex)
{
// Special case for MFT - can't fully expel attributes, instead split most of the data runs off.
List<AttributeRecord> attrs = record.Attributes;
for (int i = attrs.Count - 1; i >= 0; --i)
{
AttributeRecord attr = attrs[i];
if (attr.AttributeType == AttributeType.Data)
{
if (SplitAttribute(record, (NonResidentAttributeRecord)attr, true))
{
return true;
}
}
}
}
else
{
List<AttributeRecord> attrs = record.Attributes;
for (int i = attrs.Count - 1; i >= 0; --i)
{
AttributeRecord attr = attrs[i];
if (attr.AttributeType > AttributeType.AttributeList)
{
foreach (var targetRecord in _records)
{
if (_mft.RecordSize - targetRecord.Size >= attr.Size)
{
MoveAttribute(record, attr, targetRecord);
return true;
}
}
FileRecord newFileRecord = _mft.AllocateRecord(FileRecordFlags.None, record.IsMftRecord);
newFileRecord.BaseFile = record.Reference;
_records.Add(newFileRecord);
MoveAttribute(record, attr, newFileRecord);
return true;
}
}
}
return false;
}
private bool SplitAttribute(FileRecord record, NonResidentAttributeRecord targetAttr, bool atStart)
{
if (targetAttr.DataRuns.Count <= 1)
{
return false;
}
int splitIndex = 1;
if (!atStart)
{
List<DataRun> runs = targetAttr.DataRuns;
splitIndex = runs.Count - 1;
int saved = runs[splitIndex].Size;
while (splitIndex > 1 && record.Size - saved > record.AllocatedSize)
{
--splitIndex;
saved += runs[splitIndex].Size;
}
}
AttributeRecord newAttr = targetAttr.Split(splitIndex);
// Find a home for the new attribute record
FileRecord newAttrHome = null;
foreach (var targetRecord in _records)
{
if (!targetRecord.IsMftRecord && _mft.RecordSize - targetRecord.Size >= newAttr.Size)
{
targetRecord.AddAttribute(newAttr);
newAttrHome = targetRecord;
}
}
if (newAttrHome == null)
{
newAttrHome = _mft.AllocateRecord(_records[0].Flags & (~FileRecordFlags.InUse), record.IsMftRecord);
newAttrHome.BaseFile = record.BaseFile.IsNull ? record.Reference : record.BaseFile;
_records.Add(newAttrHome);
newAttrHome.AddAttribute(newAttr);
}
// Add the new attribute record as an extent on the attribute it split from
bool added = false;
foreach (var attr in _attributes)
{
foreach (var existingRecord in attr.Extents)
{
if (existingRecord.Key.File == record.Reference && existingRecord.Key.AttributeId == targetAttr.AttributeId)
{
attr.AddExtent(newAttrHome.Reference, newAttr);
added = true;
break;
}
}
if (added)
{
break;
}
}
UpdateAttributeList();
return true;
}
private bool SplitAttribute(FileRecord record)
{
if (record.Attributes.Count != 1)
{
throw new InvalidOperationException("Attempting to split attribute in MFT record containing multiple attributes");
}
return SplitAttribute(record, (NonResidentAttributeRecord)record.FirstAttribute, false);
}
private bool VerifyMftRecord(byte[] recordData, bool presentInBitmap, int bytesPerSector)
{
bool ok = true;
//
// Verify the attributes seem OK...
//
byte[] tempBuffer = new byte[recordData.Length];
Array.Copy(recordData, tempBuffer, tempBuffer.Length);
GenericFixupRecord genericRecord = new GenericFixupRecord(bytesPerSector);
genericRecord.FromBytes(tempBuffer, 0);
int pos = Utilities.ToUInt16LittleEndian(genericRecord.Content, 0x14);
while (Utilities.ToUInt32LittleEndian(genericRecord.Content, pos) != 0xFFFFFFFF)
{
int attrLen;
try
{
AttributeRecord ar = AttributeRecord.FromBytes(genericRecord.Content, pos, out attrLen);
if (attrLen != ar.Size)
{
ReportError("Attribute size is different to calculated size. AttrId={0}", ar.AttributeId);
ok = false;
}
if (ar.IsNonResident)
{
NonResidentAttributeRecord nrr = (NonResidentAttributeRecord)ar;
if (nrr.DataRuns.Count > 0)
{
long totalVcn = 0;
foreach (var run in nrr.DataRuns)
{
totalVcn += run.RunLength;
}
if (totalVcn != nrr.LastVcn - nrr.StartVcn + 1)
{
ReportError("Declared VCNs doesn't match data runs. AttrId={0}", ar.AttributeId);
ok = false;
}
}
}
}
catch
{
ReportError("Failure parsing attribute at pos={0}", pos);
return false;
}
pos += attrLen;
}
//
// Now consider record as a whole
//
FileRecord record = new FileRecord(bytesPerSector);
record.FromBytes(recordData, 0);
bool inUse = (record.Flags & FileRecordFlags.InUse) != 0;
if (inUse != presentInBitmap)
{
ReportError("MFT bitmap and record in-use flag don't agree. Mft={0}, Record={1}", presentInBitmap ? "InUse" : "Free", inUse ? "InUse" : "Free");
ok = false;
}
if (record.Size != record.RealSize)
{
ReportError("MFT record real size is different to calculated size. Stored in MFT={0}, Calculated={1}", record.RealSize, record.Size);
ok = false;
}
if (Utilities.ToUInt32LittleEndian(recordData, (int)record.RealSize - 8) != uint.MaxValue)
{
ReportError("MFT record is not correctly terminated with 0xFFFFFFFF");
ok = false;
}
return ok;
}
