Files
duplicati/proprietary/DiskImage/Filesystem/Unknown.cs
T
2026-03-11 15:02:23 +01:00

558 lines
21 KiB
C#

using System;
using System.Buffers;
using System.Collections.Generic;
using System.IO;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using Duplicati.Proprietary.DiskImage.Disk;
using Duplicati.Proprietary.DiskImage.General;
using Duplicati.Proprietary.DiskImage.Partition;
namespace Duplicati.Proprietary.DiskImage.Filesystem;
/// <summary>
/// Metadata for unknown filesystems, storing basic block size information.
/// </summary>
public sealed record UnkownFilesystemMetadata
{
/// <summary>
/// Gets the block size used for reading/writing data.
/// </summary>
public int BlockSize { get; init; }
}
/// <summary>
/// Represents a file in an unknown filesystem.
/// Used for raw block-based access when filesystem type cannot be determined.
/// </summary>
public class UnknownFilesystemFile : IFile
{
/// <inheritdoc />
public string? Path { get; init; }
/// <inheritdoc />
public long? Address { get; init; }
/// <inheritdoc />
public long Size { get; init; }
/// <inheritdoc />
public bool IsDirectory => false;
}
/// <summary>
/// Represents an unknown or unsupported filesystem.
/// Provides raw block-level access to partition data when the filesystem type cannot be determined.
/// </summary>
internal class UnknownFilesystem : IFilesystem
{
/// <inheritdoc />
public FileSystemType Type => FileSystemType.Unknown;
/// <inheritdoc />
public IPartition Partition { get => m_partition; }
/// <summary>
/// Gets or sets the block size used for reading/writing data. Must be a multiple of the partition sector size.
/// </summary>
private int m_blockSize;
/// <summary>
/// Flag to indicate whether the object has been disposed. Used to prevent multiple disposals and access after disposal.
/// </summary>
private bool m_disposed = false;
/// <summary>
/// The parent partition containing this filesystem.
/// </summary>
private readonly IPartition m_partition;
/// <summary>
/// Initializes a new instance of the <see cref="UnknownFilesystem"/> class.
/// </summary>
/// <param name="partition">The parent partition.</param>
/// <param name="blockSize">The block size for reading/writing (default is 1MB).</param>
/// <exception cref="ArgumentException">Thrown if block size is invalid.</exception>
public UnknownFilesystem(IPartition partition, int blockSize = 1024 * 1024)
{
m_partition = partition;
if (blockSize < 0 || blockSize % partition.PartitionTable.RawDisk?.SectorSize != 0)
throw new ArgumentException("Block size must be non-negative and a multiple of the partition sector size.", nameof(blockSize));
m_blockSize = blockSize;
}
/// <inheritdoc />
public void Dispose()
{
if (m_disposed)
return;
m_disposed = true;
}
/// <inheritdoc />
public Task<object?> GetFilesystemMetadataAsync(CancellationToken cancellationToken)
{
var cfg = new UnkownFilesystemMetadata
{
BlockSize = m_blockSize,
};
return Task.FromResult<object?>(cfg);
}
/// <inheritdoc />
public async IAsyncEnumerable<IFile> ListFilesAsync([EnumeratorCancellation] CancellationToken cancellationToken)
{
long totalSize = m_partition.Size;
long blockSize = m_blockSize;
long blockCount = (totalSize + blockSize - 1) / blockSize;
for (long i = 0; i < blockCount; i++)
{
long address = i * blockSize;
long size = Math.Min(blockSize, totalSize - i * blockSize);
if (size > 0)
yield return new UnknownFilesystemFile()
{
Address = address,
Size = size
};
}
}
/// <inheritdoc />
public async IAsyncEnumerable<IFile> ListFilesAsync(IFile directory, [EnumeratorCancellation] CancellationToken cancellationToken)
{
ArgumentNullException.ThrowIfNull(directory);
if (directory is not UnknownFilesystemFile)
throw new ArgumentException("The specified directory does not belong to this filesystem.", nameof(directory));
if (!directory.IsDirectory)
throw new ArgumentException("The specified file is not a directory.", nameof(directory));
yield break;
}
/// <summary>
/// Parses a file path to extract the corresponding block address for raw access.
/// </summary>
/// <param name="path">The file path to parse.</param>
/// <returns>The block address corresponding to the file path.</returns>
/// <exception cref="ArgumentException">Thrown if the path format is invalid.</exception>
private static long ParsePathToAddress(string path)
{
// Path format: root/part_{PartitionTableType}_{PartitionNumber}/fs_{FileSystemType}/{Address}
// We need to extract the part after the last slash
var parts = path.Split(['/', '\\'], StringSplitOptions.RemoveEmptyEntries);
if (parts.Length < 4)
throw new ArgumentException("Invalid path format.", nameof(path));
return Convert.ToInt64(parts[^1], 16);
}
/// <summary>
/// Checks if the specified range is valid for the partition.
/// </summary>
/// <param name="start">The starting address of the range.</param>
/// <param name="size">The size of the range.</param>
/// <exception cref="ArgumentOutOfRangeException">Thrown if the start or size is negative or exceeds the partition size.</exception>
/// <exception cref="ArgumentException">Thrown if the start or size is not a multiple of the sector size.</exception>
public void BoundsCheck(long start, long size)
{
if (start < 0 || size < 0)
throw new ArgumentOutOfRangeException("Start and size must be non-negative.");
if (start + size > m_partition.Size)
throw new ArgumentOutOfRangeException("The specified range exceeds the partition size.");
var sectorSize = m_partition.PartitionTable.RawDisk?.SectorSize ?? 512;
if (start % sectorSize != 0 || size % sectorSize != 0)
throw new ArgumentException($"Start and size must be multiples of the sector size ({sectorSize} bytes).");
}
/// <inheritdoc />
public async Task<Stream> OpenReadStreamAsync(IFile file, CancellationToken cancellationToken)
{
if (file is not UnknownFilesystemFile unknownFile)
throw new ArgumentException("The specified file does not belong to this filesystem.", nameof(file));
if (file.IsDirectory)
throw new ArgumentException("The specified file is a directory.", nameof(file));
long address = unknownFile.Address ?? throw new ArgumentException("File address is required.", nameof(file));
long size = unknownFile.Size;
BoundsCheck(address, size);
return new UnknownFilesystemStream(m_partition.PartitionTable.RawDisk!, m_partition.StartOffset + address, size, readEnabled: true, writeEnabled: false);
}
/// <inheritdoc />
public async Task<Stream> OpenReadStreamAsync(string path, CancellationToken cancellationToken)
{
long address = ParsePathToAddress(path);
long size = Math.Min((long)m_blockSize, m_partition.Size - address);
return await OpenReadStreamAsync(new UnknownFilesystemFile { Address = address, Size = size }, cancellationToken);
}
/// <inheritdoc />
public async Task<Stream> OpenWriteStreamAsync(IFile file, CancellationToken cancellationToken)
{
if (file is not UnknownFilesystemFile unknownFile)
throw new ArgumentException("The specified file does not belong to this filesystem.", nameof(file));
if (file.IsDirectory)
throw new ArgumentException("The specified file is a directory.", nameof(file));
long address = unknownFile.Address ?? throw new ArgumentException("File address is required.", nameof(file));
long size = unknownFile.Size;
BoundsCheck(address, size);
return new UnknownFilesystemStream(m_partition.PartitionTable.RawDisk!, m_partition.StartOffset + address, size, readEnabled: false, writeEnabled: true);
}
/// <inheritdoc />
public async Task<Stream> OpenWriteStreamAsync(string path, CancellationToken cancellationToken)
{
long address = ParsePathToAddress(path);
long size = Math.Min((long)m_blockSize, m_partition.Size - address);
return await OpenWriteStreamAsync(new UnknownFilesystemFile { Address = address, Size = size }, cancellationToken);
}
/// <inheritdoc />
public async Task<Stream> OpenReadWriteStreamAsync(IFile file, CancellationToken cancellationToken)
{
if (file is not UnknownFilesystemFile unknownFile)
throw new ArgumentException("The specified file does not belong to this filesystem.", nameof(file));
if (file.IsDirectory)
throw new ArgumentException("The specified file is a directory.", nameof(file));
long address = unknownFile.Address ?? throw new ArgumentException("File address is required.", nameof(file));
long size = unknownFile.Size;
BoundsCheck(address, size);
return new UnknownFilesystemStream(m_partition.PartitionTable.RawDisk!, m_partition.StartOffset + address, size, readEnabled: true, writeEnabled: true);
}
/// <inheritdoc />
public async Task<Stream> OpenReadWriteStreamAsync(string path, CancellationToken cancellationToken)
{
long address = ParsePathToAddress(path);
long size = Math.Min((long)m_blockSize, m_partition.Size - address);
return await OpenReadWriteStreamAsync(new UnknownFilesystemFile { Address = address, Size = size }, cancellationToken);
}
/// <inheritdoc />
public Task<long> GetFileLengthAsync(IFile file, CancellationToken cancellationToken)
{
if (file is not UnknownFilesystemFile unknownFile)
throw new ArgumentException("The specified file does not belong to this filesystem.", nameof(file));
if (file.IsDirectory)
throw new ArgumentException("The specified file is a directory.", nameof(file));
return Task.FromResult(unknownFile.Size);
}
/// <inheritdoc />
public Task<long> GetFileLengthAsync(string path, CancellationToken cancellationToken)
{
long address = ParsePathToAddress(path);
long totalSize = m_partition.Size;
long size = Math.Min((long)m_blockSize, totalSize - address);
return Task.FromResult(size);
}
/// <summary>
/// A stream that writes data directly to a specific address on the raw disk.
/// </summary>
private class UnknownFilesystemStream : Stream
{
/// <summary>
/// The raw disk to read from.
/// </summary>
private readonly IRawDisk _disk;
/// <summary>
/// The starting address on the disk for this stream.
/// </summary>
private readonly long _address;
/// <summary>
/// The size of the stream in bytes.
/// </summary>
private readonly long _size;
/// <summary>
/// The buffer used to store data before writing to disk.
/// Rented from ArrayPool to avoid LOH allocations for large buffers.
/// </summary>
private readonly byte[] _buffer;
/// <summary>
/// Indicates whether the buffer was rented from the ArrayPool and needs to be returned.
/// </summary>
private readonly bool _bufferRented;
/// <summary>
/// The current position within the buffer.
/// </summary>
private long _position;
/// <summary>
/// Indicates whether the data in the buffer is valid (has been read from disk).
/// </summary>
private bool _validData;
/// <summary>
/// Indicates whether the stream has been disposed.
/// </summary>
private bool _disposed;
/// <summary>
/// Indicates whether the stream supports reading.
/// </summary>
private readonly bool _readEnabled;
/// <summary>
/// Indicates whether the stream supports writing.
/// </summary>
private readonly bool _writeEnabled;
/// <summary>
/// Indicates whether the buffer has been modified (dirty).
/// </summary>
private bool _dirty;
/// <summary>
/// Initializes a new instance of the <see cref="UnknownFilesystemStream"/> class.
/// </summary>
/// <param name="disk">The raw disk to read from/write to.</param>
/// <param name="address">The starting address on the disk for this stream.</param>
/// <param name="size">The size of the stream in bytes.</param>
/// <param name="readEnabled">Whether reading is enabled.</param>
/// <param name="writeEnabled">Whether writing is enabled.</param>
public UnknownFilesystemStream(IRawDisk disk, long address, long size, bool readEnabled, bool writeEnabled)
{
_disk = disk;
_address = address;
_size = size;
_readEnabled = readEnabled;
_writeEnabled = writeEnabled;
// Rent buffer from ArrayPool to avoid LOH allocations for large buffers (typically 1 MB)
_buffer = ArrayPool<byte>.Shared.Rent((int)size);
_bufferRented = true;
_position = 0;
_validData = false;
_disposed = false;
_dirty = false;
}
public override bool CanRead => _readEnabled;
public override bool CanWrite => _writeEnabled;
public override bool CanSeek => true;
public override long Length => _size;
public override long Position
{
get => _position;
set
{
if (value < 0 || value > _size)
throw new ArgumentOutOfRangeException(nameof(value));
_position = value;
}
}
public override void Flush()
{
// No-op - data is written on dispose
}
public override long Seek(long offset, SeekOrigin origin)
{
long newPosition = origin switch
{
SeekOrigin.Begin => offset,
SeekOrigin.Current => _position + offset,
SeekOrigin.End => _size + offset,
_ => throw new ArgumentException("Invalid seek origin", nameof(origin))
};
if (newPosition < 0 || newPosition > _size)
throw new ArgumentOutOfRangeException(nameof(offset));
_position = newPosition;
return _position;
}
public override void SetLength(long value)
{
throw new NotSupportedException("Cannot change the length of this stream.");
}
public override int Read(byte[] buffer, int offset, int count)
{
if (!_readEnabled)
throw new NotSupportedException("Read is not supported on this stream.");
if (buffer == null)
throw new ArgumentNullException(nameof(buffer));
if (offset < 0)
throw new ArgumentOutOfRangeException(nameof(offset));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (buffer.Length - offset < count)
throw new ArgumentException("Invalid offset and count for buffer length");
if (!_validData)
{
// Load the data from disk into the buffer on the first read
// Use _size to limit the read to the actual data size, not the potentially larger rented buffer
_disk.ReadBytesAsync(_address, _buffer.AsMemory(0, (int)_size), CancellationToken.None).GetAwaiter().GetResult();
_validData = true;
}
int bytesToRead = (int)Math.Min(count, _size - _position);
if (bytesToRead <= 0)
return 0;
Buffer.BlockCopy(_buffer, (int)_position, buffer, offset, bytesToRead);
_position += bytesToRead;
return bytesToRead;
}
public override void Write(byte[] buffer, int offset, int count)
{
if (!_writeEnabled)
throw new NotSupportedException("Write is not supported on this stream.");
if (buffer == null)
throw new ArgumentNullException(nameof(buffer));
if (offset < 0)
throw new ArgumentOutOfRangeException(nameof(offset));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (buffer.Length - offset < count)
throw new ArgumentException("Invalid offset and count for buffer length");
if (_position + count > _size)
throw new ArgumentException("Write would exceed stream size");
Buffer.BlockCopy(buffer, offset, _buffer, (int)_position, count);
_position += count;
_validData = true;
_dirty = true;
}
public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
if (!_readEnabled)
throw new NotSupportedException("Read is not supported on this stream.");
if (buffer == null)
throw new ArgumentNullException(nameof(buffer));
if (offset < 0)
throw new ArgumentOutOfRangeException(nameof(offset));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (buffer.Length - offset < count)
throw new ArgumentException("Invalid offset and count for buffer length");
if (!_validData)
{
// Load the data from disk into the buffer on the first read
// Use _size to limit the read to the actual data size, not the potentially larger rented buffer
await _disk.ReadBytesAsync(_address, _buffer.AsMemory(0, (int)_size), cancellationToken);
_validData = true;
}
int bytesToRead = (int)Math.Min(count, _size - _position);
if (bytesToRead <= 0)
return 0;
Buffer.BlockCopy(_buffer, (int)_position, buffer, offset, bytesToRead);
_position += bytesToRead;
return bytesToRead;
}
public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
{
if (!_writeEnabled)
throw new NotSupportedException("Write is not supported on this stream.");
if (buffer == null)
throw new ArgumentNullException(nameof(buffer));
if (offset < 0)
throw new ArgumentOutOfRangeException(nameof(offset));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (buffer.Length - offset < count)
throw new ArgumentException("Invalid offset and count for buffer length");
if (_position + count > _size)
throw new ArgumentException("Write would exceed stream size");
Buffer.BlockCopy(buffer, offset, _buffer, (int)_position, count);
_position += count;
_validData = true;
_dirty = true;
await Task.CompletedTask;
}
protected override void Dispose(bool disposing)
{
if (!_disposed)
{
if (disposing)
{
if (_writeEnabled && _dirty)
{
// Write all buffered data to disk
_disk.WriteBytesAsync(_address, _buffer.AsMemory(0, (int)_size), CancellationToken.None).GetAwaiter().GetResult();
}
// Return the rented buffer to the pool
if (_bufferRented)
{
ArrayPool<byte>.Shared.Return(_buffer);
}
}
_disposed = true;
}
base.Dispose(disposing);
}
/// <summary>
/// Asynchronously releases the unmanaged resources used by the <see cref="UnknownFilesystemStream"/>.
/// </summary>
public override async ValueTask DisposeAsync()
{
if (!_disposed)
{
if (_writeEnabled && _dirty)
{
// Write all buffered data to disk
await _disk.WriteBytesAsync(_address, _buffer.AsMemory(0, (int)_size), CancellationToken.None);
}
// Return the rented buffer to the pool
if (_bufferRented)
{
ArrayPool<byte>.Shared.Return(_buffer);
}
_disposed = true;
}
}
}
}