Added basic GPT table parsing
This commit is contained in:
Carl Johnsen
@@ -0,0 +1,182 @@
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using System;
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using System.Collections.Generic;
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using System.IO;
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using System.Threading;
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using System.Threading.Tasks;
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using Duplicati.Proprietary.DiskImage;
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using Duplicati.Proprietary.DiskImage.Raw;
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namespace Duplicati.Proprietary.DiskImage.Partition;
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public class GPT : IPartitionTable
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{
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private const int TableSize = 4096;
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private const int HeaderSize = 92;
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private const long GptSignature = 0x5452415020494645; // "EFI PART" in little-endian
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private bool m_parsed = false;
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private bool m_disposed = false;
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// GPT Header fields
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private long m_signature;
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private uint m_revision;
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private uint m_headerSize;
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private uint m_headerCrc32;
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private long m_currentLba;
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private long m_backupLba;
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private long m_firstUsableLba;
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private long m_lastUsableLba;
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private Guid m_diskGuid;
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private long m_partitionEntryLba;
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private uint m_numPartitionEntries;
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private uint m_partitionEntrySize;
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private uint m_partitionEntryCrc32;
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// Additional tracking
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private IRawDisk? m_rawDisk;
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private byte[]? m_headerBytes;
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public GPT() { }
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// IPartitionTable implementation
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public IRawDisk? RawDisk { get; private set; }
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public PartitionTableType TableType => PartitionTableType.Gpt;
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public async Task<bool> ParseFromBytesAsync(byte[] bytes, CancellationToken token)
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{
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if (bytes.Length < TableSize)
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throw new ArgumentException($"Byte array must be at least {TableSize} bytes long.", nameof(bytes));
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// Parse GPT header (starts at LBA 1, offset 0 in our buffer)
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m_headerBytes = new byte[HeaderSize];
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Array.Copy(bytes, 512, m_headerBytes, 0, HeaderSize);
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// Read signature (8 bytes, little-endian)
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m_signature = BitConverter.ToInt64(m_headerBytes, 0);
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// Verify signature
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if (m_signature != GptSignature)
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return false;
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// Read revision (4 bytes)
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m_revision = BitConverter.ToUInt32(m_headerBytes, 8);
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// Read header size (4 bytes)
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m_headerSize = BitConverter.ToUInt32(m_headerBytes, 12);
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// Read header CRC32 (4 bytes)
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m_headerCrc32 = BitConverter.ToUInt32(m_headerBytes, 16);
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// Reserved - must be zero (4 bytes at offset 20)
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// Skip reserved field
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// Current LBA (8 bytes at offset 24)
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m_currentLba = BitConverter.ToInt64(m_headerBytes, 24);
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// Backup LBA (8 bytes at offset 32)
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m_backupLba = BitConverter.ToInt64(m_headerBytes, 32);
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// First usable LBA (8 bytes at offset 40)
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m_firstUsableLba = BitConverter.ToInt64(m_headerBytes, 40);
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// Last usable LBA (8 bytes at offset 48)
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m_lastUsableLba = BitConverter.ToInt64(m_headerBytes, 48);
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// Disk GUID (16 bytes at offset 56)
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var diskGuidBytes = new byte[16];
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Array.Copy(m_headerBytes, 56, diskGuidBytes, 0, 16);
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m_diskGuid = new Guid(diskGuidBytes);
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// Partition entry LBA (8 bytes at offset 72)
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m_partitionEntryLba = BitConverter.ToInt64(m_headerBytes, 72);
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// Number of partition entries (4 bytes at offset 80)
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m_numPartitionEntries = BitConverter.ToUInt32(m_headerBytes, 80);
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// Size of partition entry (4 bytes at offset 84)
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m_partitionEntrySize = BitConverter.ToUInt32(m_headerBytes, 84);
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// Partition entry CRC32 (4 bytes at offset 88)
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m_partitionEntryCrc32 = BitConverter.ToUInt32(m_headerBytes, 88);
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m_parsed = true;
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return true;
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}
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public async Task<bool> ParseFromDiskAsync(IRawDisk disk, CancellationToken token)
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{
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var bytes = new byte[TableSize];
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using var bytestream = await disk.ReadBytesAsync(0, TableSize, token).ConfigureAwait(false);
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await bytestream.ReadAtLeastAsync(bytes, TableSize, cancellationToken: token).ConfigureAwait(false);
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var result = await ParseFromBytesAsync(bytes, token).ConfigureAwait(false);
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if (result)
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{
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RawDisk = disk;
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m_rawDisk = disk;
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}
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return result;
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}
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// GPT-specific properties
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public long Signature => m_parsed ? m_signature : throw new InvalidOperationException("GPT header not parsed.");
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public uint Revision => m_parsed ? m_revision : throw new InvalidOperationException("GPT header not parsed.");
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public uint HeaderSizeField => m_parsed ? m_headerSize : throw new InvalidOperationException("GPT header not parsed.");
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public uint HeaderCrc32 => m_parsed ? m_headerCrc32 : throw new InvalidOperationException("GPT header not parsed.");
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public long CurrentLba => m_parsed ? m_currentLba : throw new InvalidOperationException("GPT header not parsed.");
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public long BackupLba => m_parsed ? m_backupLba : throw new InvalidOperationException("GPT header not parsed.");
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public long FirstUsableLba => m_parsed ? m_firstUsableLba : throw new InvalidOperationException("GPT header not parsed.");
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public long LastUsableLba => m_parsed ? m_lastUsableLba : throw new InvalidOperationException("GPT header not parsed.");
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public Guid DiskGuid => m_parsed ? m_diskGuid : throw new InvalidOperationException("GPT header not parsed.");
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public long PartitionEntryLba => m_parsed ? m_partitionEntryLba : throw new InvalidOperationException("GPT header not parsed.");
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public uint NumPartitionEntries => m_parsed ? m_numPartitionEntries : throw new InvalidOperationException("GPT header not parsed.");
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public uint PartitionEntrySizeField => m_parsed ? m_partitionEntrySize : throw new InvalidOperationException("GPT header not parsed.");
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public uint PartitionEntryCrc32 => m_parsed ? m_partitionEntryCrc32 : throw new InvalidOperationException("GPT header not parsed.");
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// IPartitionTable methods
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public async IAsyncEnumerable<IPartition> EnumeratePartitions([System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
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{
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if (!m_parsed)
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throw new InvalidOperationException("GPT header not parsed.");
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// TODO: Implement partition enumeration from partition entries
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yield break;
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}
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public async Task<IPartition?> GetPartitionAsync(int partitionNumber, CancellationToken cancellationToken)
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{
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if (!m_parsed)
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throw new InvalidOperationException("GPT header not parsed.");
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// TODO: Implement partition retrieval
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return null;
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}
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public async Task<Stream> GetProtectiveMbrAsync(CancellationToken cancellationToken)
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{
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if (!m_parsed)
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throw new InvalidOperationException("GPT header not parsed.");
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// TODO: Implement protective MBR retrieval
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throw new NotImplementedException();
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}
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public void Dispose()
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{
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Dispose(true);
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GC.SuppressFinalize(this);
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}
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protected virtual void Dispose(bool disposing)
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{
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if (!m_disposed)
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{
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if (disposing)
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{
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m_headerBytes = null;
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m_rawDisk = null;
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}
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m_disposed = true;
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}
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}
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}
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