/// <summary>
/// Reads the master boot block.
/// </summary>
/// <returns></returns>
public bool Read()
{
valid = false;
MasterBootBlock mbr = new MasterBootBlock(diskDevice);
if (!mbr.Valid)
return false;
if ((mbr.Partitions[0].PartitionType != PartitionType.GPT) ||
(mbr.Partitions[1].PartitionType != PartitionType.Empty) ||
(mbr.Partitions[2].PartitionType != PartitionType.Empty) ||
(mbr.Partitions[3].PartitionType != PartitionType.Empty) ||
(!mbr.Partitions[0].Bootable) || (mbr.Partitions[0].StartLBA != 1))
return false;
BinaryFormat gpt = new BinaryFormat(diskDevice.ReadBlock(1, 1));
if ((gpt.GetByte(0) != 45) && (gpt.GetByte(1) != 46) && (gpt.GetByte(2) != 49) && (gpt.GetByte(3) != 20) &&
(gpt.GetByte(4) != 50) && (gpt.GetByte(5) != 41) && (gpt.GetByte(6) != 52) && (gpt.GetByte(7) != 54))
return false;
if ((gpt.GetUInt(GPT.Revision) != GPTConstant.SupportedRevision) ||
(gpt.GetUInt(GPT.HeaderSize) != GPTConstant.HeaderSize) ||
(gpt.GetUInt(GPT.Reserved) != 0) ||
(gpt.GetUInt(GPT.PartitionStartingLBA) != 2)
)
return false;
valid = true;
return valid;
}
/// <summary>
/// Compares the specified data.
/// </summary>
/// <param name="data">The data.</param>
/// <param name="offset">The offset.</param>
/// <param name="type">The type.</param>
/// <returns></returns>
public bool Compare(byte[] data, uint offset, FatType type)
{
BinaryFormat entry = new BinaryFormat(data);
byte first = entry.GetByte(Entry.DOSName + offset);
if (first == FileNameAttribute.LastEntry)
return false;
if ((first == FileNameAttribute.Deleted) | (first == FileNameAttribute.Dot))
return false;
if (first == FileNameAttribute.Escape)
return false;
FatFileAttributes attribute = (FatFileAttributes)entry.GetByte(Entry.FileAttributes + offset);
if ((attribute & FatFileAttributes.VolumeLabel) == FatFileAttributes.VolumeLabel)
return true;
return false;
}
/// <summary>
/// Compares the specified data.
/// </summary>
/// <param name="data">The data.</param>
/// <param name="offset">The offset.</param>
/// <param name="type">The type.</param>
/// <returns></returns>
public bool Compare(byte[] data, uint offset, FatType type)
{
BinaryFormat entry = new BinaryFormat(data);
byte first = entry.GetByte(offset + Entry.DOSName);
if (first == FileNameAttribute.LastEntry)
return true;
if ((first == FileNameAttribute.Deleted) | (first == FileNameAttribute.Dot))
return true;
return false;
}
return false; if ((first == FileNameAttribute.Deleted) | (first == FileNameAttribute.Dot)) return false; if (first == FileNameAttribute.Escape) return false; uint startcluster = FatFileSystem.GetClusterEntry(data, offset, type); if (startcluster == cluster) return true; return false; } } }
/// <summary>
/// Compares the specified data.
/// </summary>
/// <param name="data">The data.</param>
/// <param name="offset">The offset.</param>
/// <param name="type">The type.</param>
/// <returns></returns>
public bool Compare(byte[] data, uint offset, FatType type)
{
var entry = new BinaryFormat(data);
byte first = entry.GetByte(offset + Entry.DOSName);
if (first == FileNameAttribute.LastEntry)
return false;
if ((first == FileNameAttribute.Deleted) | (first == FileNameAttribute.Dot))
return false;
if (first == FileNameAttribute.Escape)
return false;
string entryname = FatFileSystem.ExtractFileName(data, offset);
if (entryname == name)
return true;
return false;
}
/// <summary>
/// Finds the entry.
/// </summary>
/// <param name="compare">The compare.</param>
/// <param name="startCluster">The start cluster.</param>
/// <returns></returns>
public FatFileLocation FindEntry(FatFileSystem.ICompare compare, uint startCluster)
{
uint activeSector = startCluster * sectorsPerCluster;
if (startCluster == 0)
activeSector = (fatType == FatType.FAT32) ? GetSectorByCluster(rootCluster32) : firstRootDirectorySector;
uint increment = 0;
for (;;)
{
BinaryFormat directory = new BinaryFormat(partition.ReadBlock(activeSector, 1));
for (uint index = 0; index < entriesPerSector; index++)
{
if (compare.Compare(directory.Data, index * 32, fatType))
{
FatFileAttributes attribute = (FatFileAttributes)directory.GetByte((index * Entry.EntrySize) + Entry.FileAttributes);
return new FatFileLocation(GetClusterEntry(directory.Data, index, fatType), activeSector, index, (attribute & FatFileAttributes.SubDirectory) != 0);
}
if (directory.GetByte(Entry.DOSName + (index * Entry.EntrySize)) == FileNameAttribute.LastEntry)
return new FatFileLocation();
}
++increment;
if ((startCluster == 0) && (fatType != FatType.FAT32))
{
// FAT12/16 Root directory
if (increment >= rootDirSectors)
return new FatFileLocation();
activeSector = startCluster + increment;
continue;
}
else
{
// subdirectory
if (increment < sectorsPerCluster)
{
// still within cluster
activeSector = startCluster + increment;
continue;
}
// exiting cluster
// goto next cluster (if any)
uint cluster = GetClusterBySector(startCluster);
if (cluster == 0)
return new FatFileLocation();
uint nextCluster = GetClusterEntryValue(cluster);
if ((IsClusterLast(nextCluster)) || (IsClusterBad(nextCluster)) || (IsClusterFree(nextCluster)) || (IsClusterReserved(nextCluster)))
return new FatFileLocation();
activeSector = (uint)(dataAreaStart + (nextCluster - 1 * sectorsPerCluster));
continue;
}
}
}
/// <summary>
/// Extracts the name of the file.
/// </summary>
/// <param name="directory">The directory.</param>
/// <param name="index">The index.</param>
/// <returns></returns>
public static string ExtractFileName(byte[] directory, uint index)
{
// rewrite to use string
BinaryFormat entry = new BinaryFormat(directory);
char[] name = new char[12];
for (uint i = 0; i < 8; i++)
name[i] = (char)entry.GetByte(index + i + Entry.DOSName);
int len = 8;
for (int i = 7; i > 0; i--)
if (name[i] == ' ')
len--;
else
break;
// special case where real character is same as the delete
if ((len >= 1) && (name[0] == (char)FileNameAttribute.Escape))
name[0] = (char)FileNameAttribute.Deleted;
name[len] = '.';
len++;
for (uint i = 0; i < 3; i++)
name[len + i] = (char)entry.GetByte(index + i + Entry.DOSExtension);
len = len + 3;
int spaces = 0;
for (int i = len - 1; i >= 0; i--)
if (name[i] == ' ')
spaces++;
else
break;
if (spaces == 3)
spaces = 4;
len = len - spaces;
// FIXME
string str = string.Empty;
for (uint i = 0; i < len; i++)
str = str + (char)name[i];
return str;
}
/// <summary>
/// Reads the boot sector.
/// </summary>
/// <returns></returns>
protected bool ReadBootSector()
{
valid = false;
if (blockSize != 512) // only going to work with 512 sector sizes (for now)
return false;
BinaryFormat bootSector = new BinaryFormat(partition.ReadBlock(0, 1));
if (bootSector.GetUShort(BootSector.BootSectorSignature) != 0xAA55)
return false;
byte extendedBootSignature = bootSector.GetByte(BootSector.ExtendedBootSignature);
byte extendedBootSignature32 = bootSector.GetByte(BootSector.FAT32_ExtendedBootSignature);
if ((extendedBootSignature != 0x29) && (extendedBootSignature != 0x28) && (extendedBootSignature32 != 0x29))
return false;
volumeLabel = bootSector.GetString(BootSector.VolumeLabel, 8).ToString().TrimEnd();
bytesPerSector = bootSector.GetUShort(BootSector.BytesPerSector);
sectorsPerCluster = bootSector.GetByte(BootSector.SectorsPerCluster);
reservedSectors = bootSector.GetByte(BootSector.ReservedSectors);
nbrFats = bootSector.GetByte(BootSector.FatAllocationTables);
rootEntries = bootSector.GetUShort(BootSector.MaxRootDirEntries);
rootCluster32 = bootSector.GetUInt(BootSector.FAT32_ClusterNumberOfRoot);
uint sectorsPerFat16 = bootSector.GetUShort(BootSector.SectorsPerFAT);
uint sectorsPerFat32 = bootSector.GetUInt(BootSector.FAT32_SectorPerFAT);
uint totalSectors16 = bootSector.GetUShort(BootSector.TotalSectors16);
uint totalSectors32 = bootSector.GetUInt(BootSector.TotalSectors32);
uint sectorsPerFat = (sectorsPerFat16 != 0) ? sectorsPerFat16 : sectorsPerFat32;
uint fatSectors = 0;
try
{
fatSectors = nbrFats * sectorsPerFat;
clusterSizeInBytes = sectorsPerCluster * blockSize;
rootDirSectors = (((rootEntries * 32) + (bytesPerSector - 1)) / bytesPerSector);
firstDataSector = reservedSectors + (nbrFats * sectorsPerFat) + rootDirSectors;
totalSectors = (totalSectors16 != 0) ? totalSectors16 : totalSectors32;
dataSectors = totalSectors - (reservedSectors + (nbrFats * sectorsPerFat) + rootDirSectors);
totalClusters = dataSectors / sectorsPerCluster;
entriesPerSector = (bytesPerSector / 32);
firstRootDirectorySector = reservedSectors + fatSectors;
dataAreaStart = firstRootDirectorySector + rootDirSectors;
}
catch
{
return false;
}
// Some basic checks
if ((nbrFats == 0) || (nbrFats > 2) || (totalSectors == 0) || (sectorsPerFat == 0))
return false;
if (totalClusters < 4085)
fatType = FatType.FAT12;
else if (totalClusters < 65525)
fatType = FatType.FAT16;
else
fatType = FatType.FAT32;
if (fatType == FatType.FAT12)
{
reservedClusterMark = 0xFF0;
endOfClusterMark = 0x0FF8;
badClusterMark = 0x0FF7;
fatMask = 0xFFFFFFFF;
fatEntries = sectorsPerFat * 3 * blockSize / 2;
}
else if (fatType == FatType.FAT16)
{
reservedClusterMark = 0xFFF0;
endOfClusterMark = 0xFFF8;
badClusterMark = 0xFFF7;
fatMask = 0xFFFFFFFF;
fatEntries = sectorsPerFat * blockSize / 2;
}
else
{ // if (type == FatType.FAT32) {
reservedClusterMark = 0xFFF0;
endOfClusterMark = 0x0FFFFFF8;
badClusterMark = 0x0FFFFFF7;
fatMask = 0x0FFFFFFF;
fatEntries = sectorsPerFat * blockSize / 4;
}
// More basic checks
if ((fatType == FatType.FAT32) && (rootCluster32 == 0))
return false;
valid = true;
serialNbr = bootSector.GetBytes(fatType != FatType.FAT32 ? BootSector.IDSerialNumber : BootSector.FAT32_IDSerialNumber, 4);
return true;
}
/// <summary>
/// Reads the master boot block.
/// </summary>
/// <returns></returns>
public bool Read()
{
valid = false;
if (diskDevice.BlockSize != 512) return false; // only going to work with 512 sector sizes
if (diskDevice.TotalBlocks < 3) return false;
BinaryFormat masterboot = new BinaryFormat(diskDevice.ReadBlock(0, 1));
if (masterboot.GetUShort(MBR.MBRSignature) != MBRConstant.MBRSignature)
return false;
valid = true;
diskSignature = masterboot.GetUInt(MBR.DiskSignature);
for (uint index = 0; index < MaxMBRPartitions; index++) {
uint offset = MBR.FirstPartition + (index * MBRConstant.PartitionSize);
GenericPartition partition = new GenericPartition(index);
partition.Bootable = masterboot.GetByte(offset + PartitionRecord.Status) == MBRConstant.Bootable;
partition.PartitionType = masterboot.GetByte(offset + PartitionRecord.PartitionType);
partition.StartLBA = masterboot.GetUInt(offset + PartitionRecord.LBA);
partition.TotalBlocks = masterboot.GetUInt(offset + PartitionRecord.Sectors);
Partitions[index] = partition;
}
//TODO: Extended Partitions
code = new byte[MBRConstant.CodeAreaSize];
for (uint index = 0; index < MBRConstant.CodeAreaSize; index++)
code[index] = masterboot.GetByte(index);
return valid;
}
