Btrfs is a copy on write file system based on B-trees focusing on fault tolerance, repair and easy
administration. Btrfs is intended to address the lack of pooling, snapshots, checksums, and
integral multi-device spanning in Linux file systems.
Given any pair of subvolumes (or snapshots), Btrfs can generate a binary diff between them by
using the btrfs send command that can be replayed later by using btrfs receive, possibly on a
different Btrfs file system. The btrfs send command creates a set of data modifications required
for converting one subvolume into another.
This spec can be used to disassemble the binary diff created by the btrfs send command.
If you want a text representation you may want to checkout btrfs receive --dump instead.
This page hosts a formal specification of btrfs_stream using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
All parsing code for C# generated by Kaitai Struct depends on the C# runtime library. You have to install it before you can parse data.
The C# runtime library is available in the NuGet Gallery. Installation instructions can also be found there.
Parse a local file and get structure in memory:
var data = BtrfsStream.FromFile("path/to/local/file.bin");
Or parse structure from a byte array:
byte[] someArray = new byte[] { ... };
var data = new BtrfsStream(new KaitaiStream(someArray));
After that, one can get various attributes from the structure by accessing properties like:
data.Header // => get header
// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
using System.Collections.Generic;
namespace Kaitai
{
/// <summary>
/// Btrfs is a copy on write file system based on B-trees focusing on fault tolerance, repair and easy
/// administration. Btrfs is intended to address the lack of pooling, snapshots, checksums, and
/// integral multi-device spanning in Linux file systems.
/// Given any pair of subvolumes (or snapshots), Btrfs can generate a binary diff between them by
/// using the `btrfs send` command that can be replayed later by using `btrfs receive`, possibly on a
/// different Btrfs file system. The `btrfs send` command creates a set of data modifications required
/// for converting one subvolume into another.
/// This spec can be used to disassemble the binary diff created by the `btrfs send` command.
/// If you want a text representation you may want to checkout `btrfs receive --dump` instead.
/// </summary>
/// <remarks>
/// Reference: <a href="https://archive.kernel.org/oldwiki/btrfs.wiki.kernel.org/index.php/Design_notes_on_Send/Receive.html">Source</a>
/// </remarks>
public partial class BtrfsStream : KaitaiStruct
{
public static BtrfsStream FromFile(string fileName)
{
return new BtrfsStream(new KaitaiStream(fileName));
}
public enum Command
{
Unspec = 0,
Subvol = 1,
Snapshot = 2,
Mkfile = 3,
Mkdir = 4,
Mknod = 5,
Mkfifo = 6,
Mksock = 7,
Symlink = 8,
Rename = 9,
Link = 10,
Unlink = 11,
Rmdir = 12,
SetXattr = 13,
RemoveXattr = 14,
Write = 15,
Clone = 16,
Truncate = 17,
Chmod = 18,
Chown = 19,
Utimes = 20,
End = 21,
UpdateExtent = 22,
}
public enum Attribute
{
Unspec = 0,
Uuid = 1,
Ctransid = 2,
Ino = 3,
Size = 4,
Mode = 5,
Uid = 6,
Gid = 7,
Rdev = 8,
Ctime = 9,
Mtime = 10,
Atime = 11,
Otime = 12,
XattrName = 13,
XattrData = 14,
Path = 15,
PathTo = 16,
PathLink = 17,
FileOffset = 18,
Data = 19,
CloneUuid = 20,
CloneCtransid = 21,
ClonePath = 22,
CloneOffset = 23,
CloneLen = 24,
}
public BtrfsStream(KaitaiStream p__io, KaitaiStruct p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root ?? this;
_read();
}
private void _read()
{
_header = new SendStreamHeader(m_io, this, m_root);
_commands = new List<SendCommand>();
{
var i = 0;
while (!m_io.IsEof) {
_commands.Add(new SendCommand(m_io, this, m_root));
i++;
}
}
}
public partial class SendStreamHeader : KaitaiStruct
{
public static SendStreamHeader FromFile(string fileName)
{
return new SendStreamHeader(new KaitaiStream(fileName));
}
public SendStreamHeader(KaitaiStream p__io, BtrfsStream p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_magic = m_io.ReadBytes(13);
if (!((KaitaiStream.ByteArrayCompare(Magic, new byte[] { 98, 116, 114, 102, 115, 45, 115, 116, 114, 101, 97, 109, 0 }) == 0)))
{
throw new ValidationNotEqualError(new byte[] { 98, 116, 114, 102, 115, 45, 115, 116, 114, 101, 97, 109, 0 }, Magic, M_Io, "/types/send_stream_header/seq/0");
}
_version = m_io.ReadU4le();
}
private byte[] _magic;
private uint _version;
private BtrfsStream m_root;
private BtrfsStream m_parent;
public byte[] Magic { get { return _magic; } }
public uint Version { get { return _version; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream M_Parent { get { return m_parent; } }
}
public partial class SendCommand : KaitaiStruct
{
public static SendCommand FromFile(string fileName)
{
return new SendCommand(new KaitaiStream(fileName));
}
public SendCommand(KaitaiStream p__io, BtrfsStream p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_lenData = m_io.ReadU4le();
_type = ((BtrfsStream.Command) m_io.ReadU2le());
_checksum = m_io.ReadBytes(4);
__raw_data = m_io.ReadBytes(LenData);
var io___raw_data = new KaitaiStream(__raw_data);
_data = new Tlvs(io___raw_data, this, m_root);
}
public partial class Tlv : KaitaiStruct
{
public static Tlv FromFile(string fileName)
{
return new Tlv(new KaitaiStream(fileName));
}
public Tlv(KaitaiStream p__io, BtrfsStream.SendCommand.Tlvs p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_type = ((BtrfsStream.Attribute) m_io.ReadU2le());
_length = m_io.ReadU2le();
switch (Type) {
case BtrfsStream.Attribute.Ctransid: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.Size: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.CloneUuid: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new Uuid(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.FileOffset: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.Otime: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new Timespec(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.Uid: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.Atime: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new Timespec(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.Ctime: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new Timespec(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.Uuid: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new Uuid(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.CloneLen: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.XattrName: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new String(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.CloneCtransid: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.Mode: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.Mtime: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new Timespec(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.PathLink: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new String(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.Rdev: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.PathTo: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new String(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.Path: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new String(io___raw_value, this, m_root);
break;
}
case BtrfsStream.Attribute.CloneOffset: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.Gid: {
_value = m_io.ReadU8le();
break;
}
case BtrfsStream.Attribute.ClonePath: {
__raw_value = m_io.ReadBytes(Length);
var io___raw_value = new KaitaiStream(__raw_value);
_value = new String(io___raw_value, this, m_root);
break;
}
default: {
_value = m_io.ReadBytes(Length);
break;
}
}
}
private Attribute _type;
private ushort _length;
private object _value;
private BtrfsStream m_root;
private BtrfsStream.SendCommand.Tlvs m_parent;
private byte[] __raw_value;
public Attribute Type { get { return _type; } }
public ushort Length { get { return _length; } }
public object Value { get { return _value; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream.SendCommand.Tlvs M_Parent { get { return m_parent; } }
public byte[] M_RawValue { get { return __raw_value; } }
}
public partial class Uuid : KaitaiStruct
{
public static Uuid FromFile(string fileName)
{
return new Uuid(new KaitaiStream(fileName));
}
public Uuid(KaitaiStream p__io, BtrfsStream.SendCommand.Tlv p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_uuid = m_io.ReadBytes(16);
}
private byte[] _uuid;
private BtrfsStream m_root;
private BtrfsStream.SendCommand.Tlv m_parent;
public byte[] Uuid { get { return _uuid; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream.SendCommand.Tlv M_Parent { get { return m_parent; } }
}
public partial class Tlvs : KaitaiStruct
{
public static Tlvs FromFile(string fileName)
{
return new Tlvs(new KaitaiStream(fileName));
}
public Tlvs(KaitaiStream p__io, BtrfsStream.SendCommand p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_tlv = new List<Tlv>();
{
var i = 0;
while (!m_io.IsEof) {
_tlv.Add(new Tlv(m_io, this, m_root));
i++;
}
}
}
private List<Tlv> _tlv;
private BtrfsStream m_root;
private BtrfsStream.SendCommand m_parent;
public List<Tlv> Tlv { get { return _tlv; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream.SendCommand M_Parent { get { return m_parent; } }
}
public partial class String : KaitaiStruct
{
public static String FromFile(string fileName)
{
return new String(new KaitaiStream(fileName));
}
public String(KaitaiStream p__io, BtrfsStream.SendCommand.Tlv p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_string = System.Text.Encoding.GetEncoding("UTF-8").GetString(m_io.ReadBytesFull());
}
private string _string;
private BtrfsStream m_root;
private BtrfsStream.SendCommand.Tlv m_parent;
public string String { get { return _string; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream.SendCommand.Tlv M_Parent { get { return m_parent; } }
}
public partial class Timespec : KaitaiStruct
{
public static Timespec FromFile(string fileName)
{
return new Timespec(new KaitaiStream(fileName));
}
public Timespec(KaitaiStream p__io, BtrfsStream.SendCommand.Tlv p__parent = null, BtrfsStream p__root = null) : base(p__io)
{
m_parent = p__parent;
m_root = p__root;
_read();
}
private void _read()
{
_tsSec = m_io.ReadS8le();
_tsNsec = m_io.ReadS4le();
}
private long _tsSec;
private int _tsNsec;
private BtrfsStream m_root;
private BtrfsStream.SendCommand.Tlv m_parent;
public long TsSec { get { return _tsSec; } }
public int TsNsec { get { return _tsNsec; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream.SendCommand.Tlv M_Parent { get { return m_parent; } }
}
private uint _lenData;
private Command _type;
private byte[] _checksum;
private Tlvs _data;
private BtrfsStream m_root;
private BtrfsStream m_parent;
private byte[] __raw_data;
public uint LenData { get { return _lenData; } }
public Command Type { get { return _type; } }
/// <summary>
/// CRC32 checksum of a whole send command, including the header, with this attribute set to 0.
/// </summary>
public byte[] Checksum { get { return _checksum; } }
public Tlvs Data { get { return _data; } }
public BtrfsStream M_Root { get { return m_root; } }
public BtrfsStream M_Parent { get { return m_parent; } }
public byte[] M_RawData { get { return __raw_data; } }
}
private SendStreamHeader _header;
private List<SendCommand> _commands;
private BtrfsStream m_root;
private KaitaiStruct m_parent;
public SendStreamHeader Header { get { return _header; } }
public List<SendCommand> Commands { get { return _commands; } }
public BtrfsStream M_Root { get { return m_root; } }
public KaitaiStruct M_Parent { get { return m_parent; } }
}
}