Class: Omnizip::Formats::Rpm::Lead

Inherits:
Object
  • Object
show all
Includes:
Constants
Defined in:
lib/omnizip/formats/rpm/lead.rb

Overview

RPM lead structure parser

The lead is a 96-byte deprecated header at the start of RPM files. It contains basic package identification but most information is now stored in the main header.

Constant Summary

Constants included from Constants

Constants::FILE_CONFIG, Constants::FILE_DOC, Constants::FILE_LICENSE, Constants::FILE_README, Constants::FLAG_EQUAL, Constants::FLAG_GREATER, Constants::FLAG_LESS, Constants::HEADER_HEADER_SIZE, Constants::HEADER_MAGIC, Constants::HEADER_SIGNED_TYPE, Constants::LEAD_MAGIC, Constants::LEAD_SIZE, Constants::PACKAGE_BINARY, Constants::PACKAGE_SOURCE, Constants::TAG_ENTRY_SIZE, Constants::TYPE_BINARY, Constants::TYPE_CHAR, Constants::TYPE_I18NSTRING, Constants::TYPE_INT16, Constants::TYPE_INT32, Constants::TYPE_INT64, Constants::TYPE_INT8, Constants::TYPE_NULL, Constants::TYPE_STRING, Constants::TYPE_STRING_ARRAY

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(magic:, major_version:, minor_version:, type:, architecture:, name:, os:, signature_type:, length: LEAD_SIZE) ⇒ Lead

Initialize a parsed lead. All attributes are required; use Lead.parse(io) for the typical read path.



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# File 'lib/omnizip/formats/rpm/lead.rb', line 43

def initialize(magic:, major_version:, minor_version:, type:,
               architecture:, name:, os:, signature_type:,
               length: LEAD_SIZE)
  @magic = magic
  @major_version = major_version
  @minor_version = minor_version
  @type = type
  @architecture = architecture
  @name = name
  @os = os
  @signature_type = signature_type
  @length = length
end

Instance Attribute Details

#architecture ⇒ Integer (readonly)

Returns Architecture number.

Returns:

  • (Integer) —

    Architecture number



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# File 'lib/omnizip/formats/rpm/lead.rb', line 27

def architecture
  @architecture
end

#length ⇒ Integer (readonly)

Returns Total length (always 96).

Returns:

  • (Integer) —

    Total length (always 96)



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# File 'lib/omnizip/formats/rpm/lead.rb', line 39

def length
  @length
end

#magic ⇒ String (readonly)

Returns 4-byte magic.

Returns:

  • (String) —

    4-byte magic



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# File 'lib/omnizip/formats/rpm/lead.rb', line 15

def magic
  @magic
end

#major_version ⇒ Integer (readonly)

Returns Major version.

Returns:

  • (Integer) —

    Major version



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# File 'lib/omnizip/formats/rpm/lead.rb', line 18

def major_version
  @major_version
end

#minor_version ⇒ Integer (readonly)

Returns Minor version.

Returns:

  • (Integer) —

    Minor version



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# File 'lib/omnizip/formats/rpm/lead.rb', line 21

def minor_version
  @minor_version
end

#name ⇒ String (readonly)

Returns Package name (66 bytes).

Returns:

  • (String) —

    Package name (66 bytes)



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# File 'lib/omnizip/formats/rpm/lead.rb', line 30

def name
  @name
end

#os ⇒ Integer (readonly)

Returns OS number.

Returns:

  • (Integer) —

    OS number



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# File 'lib/omnizip/formats/rpm/lead.rb', line 33

def os
  @os
end

#signature_type ⇒ Integer (readonly)

Returns Signature type.

Returns:

  • (Integer) —

    Signature type



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# File 'lib/omnizip/formats/rpm/lead.rb', line 36

def signature_type
  @signature_type
end

#type ⇒ Integer (readonly)

Returns Package type (binary=0, source=1).

Returns:

  • (Integer) —

    Package type (binary=0, source=1)



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# File 'lib/omnizip/formats/rpm/lead.rb', line 24

def type
  @type
end

Class Method Details

.parse(io) ⇒ Lead

Parse lead from IO

Parameters:

  • io (IO) —

    Input stream positioned at lead

Returns:

  • (Lead) —

    Parsed lead object

Raises:

  • (ArgumentError) —

    If magic is invalid



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# File 'lib/omnizip/formats/rpm/lead.rb', line 62

def self.parse(io)
  data = io.read(LEAD_SIZE)
  raise ArgumentError, "Failed to read RPM lead" unless data
  raise ArgumentError, "Truncated RPM lead" if data.bytesize < LEAD_SIZE

  # Unpack lead structure
  # A4 = 4-byte string (magic)
  # CC = 2 unsigned chars (major, minor)
  # n = big-endian short (type)
  # n = big-endian short (architecture)
  # A66 = 66-byte string (name)
  # n = big-endian short (os)
  # n = big-endian short (signature_type)
  # A16 = 16-byte reserved
  magic, major, minor, type, arch, name, os, sig_type = data.unpack("A4 CC n n A66 n n A16")

  new(
    magic: magic,
    major_version: major,
    minor_version: minor,
    type: type,
    architecture: arch,
    name: name.strip,
    os: os,
    signature_type: sig_type,
  ).tap(&:validate!)
end

Instance Method Details

#binary? ⇒ Boolean

Check if package is binary

Returns:

  • (Boolean) 


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# File 'lib/omnizip/formats/rpm/lead.rb', line 112

def binary?
  @type == PACKAGE_BINARY
end

#source? ⇒ Boolean

Check if package is source

Returns:

  • (Boolean) 


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# File 'lib/omnizip/formats/rpm/lead.rb', line 119

def source?
  @type == PACKAGE_SOURCE
end

#type_name ⇒ Symbol

Get type name

Returns:

  • (Symbol) —

    :binary or :source



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# File 'lib/omnizip/formats/rpm/lead.rb', line 126

def type_name
  binary? ? :binary : :source
end

#validate! ⇒ Object

Validate lead structure

Raises:

  • (ArgumentError) —

    If validation fails



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# File 'lib/omnizip/formats/rpm/lead.rb', line 93

def validate!
  if @magic.nil? || @magic.bytesize < 4
    raise ArgumentError, "Invalid RPM magic: missing or truncated"
  end

  unless @magic == LEAD_MAGIC
    raise ArgumentError,
          format("Invalid RPM magic: 0x%08x (expected 0x%08x)",
                 @magic.unpack1("N"), LEAD_MAGIC.unpack1("N"))
  end

  unless [PACKAGE_BINARY, PACKAGE_SOURCE].include?(@type)
    raise ArgumentError, "Invalid RPM type: #{@type}"
  end
end