U-Boot Image wrapper: Ruby parsing library

The new uImage format allows more flexibility in handling images of various types (kernel, ramdisk, etc.), it also enhances integrity protection of images with sha1 and md5 checksums.

KS implementation details

License: CC0-1.0

This page hosts a formal specification of U-Boot Image wrapper using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Ruby generated by Kaitai Struct depends on the Ruby runtime library. You have to install it before you can parse data.

The Ruby runtime library can be installed from RubyGems:

gem install kaitai-struct

Code

Parse a local file and get structure in memory:

data = Uimage.from_file("path/to/local/file.U-Boot Image wrapper")

Or parse structure from a string of bytes:

bytes = "\x00\x01\x02..."
data = Uimage.new(Kaitai::Struct::Stream.new(bytes))

After that, one can get various attributes from the structure by invoking getter methods like:

data.header # => get header

Ruby source code to parse U-Boot Image wrapper

uimage.rb

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

require 'kaitai/struct/struct'

unless Gem::Version.new(Kaitai::Struct::VERSION) >= Gem::Version.new('0.9')
  raise "Incompatible Kaitai Struct Ruby API: 0.9 or later is required, but you have #{Kaitai::Struct::VERSION}"
end


##
# The new uImage format allows more flexibility in handling images of various
# types (kernel, ramdisk, etc.), it also enhances integrity protection of images
# with sha1 and md5 checksums.
# @see https://source.denx.de/u-boot/u-boot/-/raw/e4dba4b/include/image.h Source
class Uimage < Kaitai::Struct::Struct

  UIMAGE_OS = {
    0 => :uimage_os_invalid,
    1 => :uimage_os_openbsd,
    2 => :uimage_os_netbsd,
    3 => :uimage_os_freebsd,
    4 => :uimage_os_bsd4_4,
    5 => :uimage_os_linux,
    6 => :uimage_os_svr4,
    7 => :uimage_os_esix,
    8 => :uimage_os_solaris,
    9 => :uimage_os_irix,
    10 => :uimage_os_sco,
    11 => :uimage_os_dell,
    12 => :uimage_os_ncr,
    13 => :uimage_os_lynxos,
    14 => :uimage_os_vxworks,
    15 => :uimage_os_psos,
    16 => :uimage_os_qnx,
    17 => :uimage_os_u_boot,
    18 => :uimage_os_rtems,
    19 => :uimage_os_artos,
    20 => :uimage_os_unity,
    21 => :uimage_os_integrity,
    22 => :uimage_os_ose,
    23 => :uimage_os_plan9,
    24 => :uimage_os_openrtos,
    25 => :uimage_os_arm_trusted_firmware,
    26 => :uimage_os_tee,
    27 => :uimage_os_opensbi,
    28 => :uimage_os_efi,
  }
  I__UIMAGE_OS = UIMAGE_OS.invert

  UIMAGE_ARCH = {
    0 => :uimage_arch_invalid,
    1 => :uimage_arch_alpha,
    2 => :uimage_arch_arm,
    3 => :uimage_arch_i386,
    4 => :uimage_arch_ia64,
    5 => :uimage_arch_mips,
    6 => :uimage_arch_mips64,
    7 => :uimage_arch_ppc,
    8 => :uimage_arch_s390,
    9 => :uimage_arch_sh,
    10 => :uimage_arch_sparc,
    11 => :uimage_arch_sparc64,
    12 => :uimage_arch_m68k,
    13 => :uimage_arch_nios,
    14 => :uimage_arch_microblaze,
    15 => :uimage_arch_nios2,
    16 => :uimage_arch_blackfin,
    17 => :uimage_arch_avr32,
    18 => :uimage_arch_st200,
    19 => :uimage_arch_sandbox,
    20 => :uimage_arch_nds32,
    21 => :uimage_arch_openrisc,
    22 => :uimage_arch_arm64,
    23 => :uimage_arch_arc,
    24 => :uimage_arch_x86_64,
    25 => :uimage_arch_xtensa,
    26 => :uimage_arch_riscv,
  }
  I__UIMAGE_ARCH = UIMAGE_ARCH.invert

  UIMAGE_COMP = {
    0 => :uimage_comp_none,
    1 => :uimage_comp_gzip,
    2 => :uimage_comp_bzip2,
    3 => :uimage_comp_lzma,
    4 => :uimage_comp_lzo,
    5 => :uimage_comp_lz4,
    6 => :uimage_comp_zstd,
  }
  I__UIMAGE_COMP = UIMAGE_COMP.invert

  UIMAGE_TYPE = {
    0 => :uimage_type_invalid,
    1 => :uimage_type_standalone,
    2 => :uimage_type_kernel,
    3 => :uimage_type_ramdisk,
    4 => :uimage_type_multi,
    5 => :uimage_type_firmware,
    6 => :uimage_type_script,
    7 => :uimage_type_filesystem,
    8 => :uimage_type_flatdt,
    9 => :uimage_type_kwbimage,
    10 => :uimage_type_imximage,
    11 => :uimage_type_ublimage,
    12 => :uimage_type_omapimage,
    13 => :uimage_type_aisimage,
    14 => :uimage_type_kernel_noload,
    15 => :uimage_type_pblimage,
    16 => :uimage_type_mxsimage,
    17 => :uimage_type_gpimage,
    18 => :uimage_type_atmelimage,
    19 => :uimage_type_socfpgaimage,
    20 => :uimage_type_x86_setup,
    21 => :uimage_type_lpc32xximage,
    22 => :uimage_type_loadable,
    23 => :uimage_type_rkimage,
    24 => :uimage_type_rksd,
    25 => :uimage_type_rkspi,
    26 => :uimage_type_zynqimage,
    27 => :uimage_type_zynqmpimage,
    28 => :uimage_type_zynqmpbif,
    29 => :uimage_type_fpga,
    30 => :uimage_type_vybridimage,
    31 => :uimage_type_tee,
    32 => :uimage_type_firmware_ivt,
    33 => :uimage_type_pmmc,
    34 => :uimage_type_stm32image,
    35 => :uimage_type_socfpgaimage_v1,
    36 => :uimage_type_mtkimage,
    37 => :uimage_type_imx8mimage,
    38 => :uimage_type_imx8image,
    39 => :uimage_type_copro,
    40 => :uimage_type_sunxi_egon,
  }
  I__UIMAGE_TYPE = UIMAGE_TYPE.invert
  def initialize(_io, _parent = nil, _root = self)
    super(_io, _parent, _root)
    _read
  end

  def _read
    @header = Uheader.new(@_io, self, @_root)
    @data = @_io.read_bytes(header.len_image)
    self
  end
  class Uheader < Kaitai::Struct::Struct
    def initialize(_io, _parent = nil, _root = self)
      super(_io, _parent, _root)
      _read
    end

    def _read
      @magic = @_io.read_bytes(4)
      raise Kaitai::Struct::ValidationNotEqualError.new([39, 5, 25, 86].pack('C*'), magic, _io, "/types/uheader/seq/0") if not magic == [39, 5, 25, 86].pack('C*')
      @header_crc = @_io.read_u4be
      @timestamp = @_io.read_u4be
      @len_image = @_io.read_u4be
      @load_address = @_io.read_u4be
      @entry_address = @_io.read_u4be
      @data_crc = @_io.read_u4be
      @os_type = Kaitai::Struct::Stream::resolve_enum(Uimage::UIMAGE_OS, @_io.read_u1)
      @architecture = Kaitai::Struct::Stream::resolve_enum(Uimage::UIMAGE_ARCH, @_io.read_u1)
      @image_type = Kaitai::Struct::Stream::resolve_enum(Uimage::UIMAGE_TYPE, @_io.read_u1)
      @compression_type = Kaitai::Struct::Stream::resolve_enum(Uimage::UIMAGE_COMP, @_io.read_u1)
      @name = (Kaitai::Struct::Stream::bytes_terminate(@_io.read_bytes(32), 0, false)).force_encoding("UTF-8")
      self
    end
    attr_reader :magic
    attr_reader :header_crc
    attr_reader :timestamp
    attr_reader :len_image
    attr_reader :load_address
    attr_reader :entry_address
    attr_reader :data_crc
    attr_reader :os_type
    attr_reader :architecture
    attr_reader :image_type
    attr_reader :compression_type
    attr_reader :name
  end
  attr_reader :header
  attr_reader :data
end