Class: Omnizip::Formats::Cpio::Entry

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

Overview

CPIO archive entry

Represents a file, directory, or special file in a CPIO archive. Supports newc, CRC, and ODC formats.

Constant Summary

Constants included from Constants

Constants::MAGIC_BINARY, Constants::MAGIC_CRC, Constants::MAGIC_NEWC, Constants::MAGIC_ODC, Constants::NEWC_ALIGNMENT, Constants::NEWC_HEADER_SIZE, Constants::S_IFBLK, Constants::S_IFCHR, Constants::S_IFDIR, Constants::S_IFIFO, Constants::S_IFLNK, Constants::S_IFMT, Constants::S_IFREG, Constants::S_IFSOCK, Constants::S_IRGRP, Constants::S_IROTH, Constants::S_IRUSR, Constants::S_IRWXG, Constants::S_IRWXO, Constants::S_IRWXU, Constants::S_ISGID, Constants::S_ISUID, Constants::S_ISVTX, Constants::S_IWGRP, Constants::S_IWOTH, Constants::S_IWUSR, Constants::S_IXGRP, Constants::S_IXOTH, Constants::S_IXUSR, Constants::TRAILER_NAME

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(attributes = {}) ⇒ Entry

Initialize CPIO entry

Parameters:

  • attributes (Hash) (defaults to: {}) —

    Entry attributes



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# File 'lib/omnizip/formats/cpio/entry.rb', line 64

def initialize(attributes = {})
  @magic = attributes.fetch(:magic, MAGIC_NEWC)
  @ino = attributes.fetch(:ino, 0)
  @mode = attributes.fetch(:mode, S_IFREG | 0o644)
  @uid = attributes.fetch(:uid, 0)
  @gid = attributes.fetch(:gid, 0)
  @nlink = attributes.fetch(:nlink, 1)
  @mtime = attributes.fetch(:mtime, Time.now.to_i)
  @filesize = attributes.fetch(:filesize, 0)
  @dev_major = attributes.fetch(:dev_major, 0)
  @dev_minor = attributes.fetch(:dev_minor, 0)
  @rdev_major = attributes.fetch(:rdev_major, 0)
  @rdev_minor = attributes.fetch(:rdev_minor, 0)
  @namesize = attributes.fetch(:namesize, 0)
  @checksum = attributes.fetch(:checksum, 0)
  @name = attributes.fetch(:name, "")
  @data = attributes.fetch(:data, "")

  # Auto-calculate namesize if not provided
  @namesize = @name.bytesize + 1 if @namesize.zero? && !@name.empty?
  @filesize = @data.bytesize if @filesize.zero? && !@data.empty?
end

Instance Attribute Details

#checksum ⇒ Integer

Returns Checksum (CRC format only).

Returns:

  • (Integer) —

    Checksum (CRC format only)



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# File 'lib/omnizip/formats/cpio/entry.rb', line 53

def checksum
  @checksum
end

#data ⇒ String

Returns File data.

Returns:

  • (String) —

    File data



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# File 'lib/omnizip/formats/cpio/entry.rb', line 59

def data
  @data
end

#dev_major ⇒ Integer

Returns Device major number.

Returns:

  • (Integer) —

    Device major number



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# File 'lib/omnizip/formats/cpio/entry.rb', line 38

def dev_major
  @dev_major
end

#dev_minor ⇒ Integer

Returns Device minor number.

Returns:

  • (Integer) —

    Device minor number



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# File 'lib/omnizip/formats/cpio/entry.rb', line 41

def dev_minor
  @dev_minor
end

#filesize ⇒ Integer

Returns File size in bytes.

Returns:

  • (Integer) —

    File size in bytes



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# File 'lib/omnizip/formats/cpio/entry.rb', line 35

def filesize
  @filesize
end

#gid ⇒ Integer

Returns Group ID.

Returns:

  • (Integer) —

    Group ID



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# File 'lib/omnizip/formats/cpio/entry.rb', line 26

def gid
  @gid
end

#ino ⇒ Integer

Returns Inode number.

Returns:

  • (Integer) —

    Inode number



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# File 'lib/omnizip/formats/cpio/entry.rb', line 17

def ino
  @ino
end

#magic ⇒ String

Returns Magic number identifying format.

Returns:

  • (String) —

    Magic number identifying format



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# File 'lib/omnizip/formats/cpio/entry.rb', line 14

def magic
  @magic
end

#mode ⇒ Integer

Returns File mode and type.

Returns:

  • (Integer) —

    File mode and type



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# File 'lib/omnizip/formats/cpio/entry.rb', line 20

def mode
  @mode
end

#mtime ⇒ Integer

Returns Modification time (Unix timestamp).

Returns:

  • (Integer) —

    Modification time (Unix timestamp)



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# File 'lib/omnizip/formats/cpio/entry.rb', line 32

def mtime
  @mtime
end

#name ⇒ String

Returns Entry name/path.

Returns:

  • (String) —

    Entry name/path



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# File 'lib/omnizip/formats/cpio/entry.rb', line 56

def name
  @name
end

#namesize ⇒ Integer

Returns Filename length (including null terminator).

Returns:

  • (Integer) —

    Filename length (including null terminator)



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# File 'lib/omnizip/formats/cpio/entry.rb', line 50

def namesize
  @namesize
end

#nlink ⇒ Integer

Returns Number of hard links.

Returns:

  • (Integer) —

    Number of hard links



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# File 'lib/omnizip/formats/cpio/entry.rb', line 29

def nlink
  @nlink
end

#rdev_major ⇒ Integer

Returns Special device major number (for device files).

Returns:

  • (Integer) —

    Special device major number (for device files)



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# File 'lib/omnizip/formats/cpio/entry.rb', line 44

def rdev_major
  @rdev_major
end

#rdev_minor ⇒ Integer

Returns Special device minor number (for device files).

Returns:

  • (Integer) —

    Special device minor number (for device files)



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# File 'lib/omnizip/formats/cpio/entry.rb', line 47

def rdev_minor
  @rdev_minor
end

#uid ⇒ Integer

Returns User ID.

Returns:

  • (Integer) —

    User ID



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# File 'lib/omnizip/formats/cpio/entry.rb', line 23

def uid
  @uid
end

Class Method Details

.detect_format(magic) ⇒ Symbol

Detect CPIO format from magic

Parameters:

  • magic (String) —

    Magic bytes

Returns:

  • (Symbol) —

    Format type



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# File 'lib/omnizip/formats/cpio/entry.rb', line 237

def self.detect_format(magic)
  case magic
  when MAGIC_NEWC then :newc
  when MAGIC_CRC then :crc
  when MAGIC_ODC then :odc
  else
    # Try binary format
    magic_int = magic.unpack1("n")
    magic_int == MAGIC_BINARY ? :binary : nil
  end
end

.padding_to_align(size, alignment) ⇒ Object

Class method for padding calculation



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# File 'lib/omnizip/formats/cpio/entry.rb', line 376

def self.padding_to_align(size, alignment)
  remainder = size % alignment
  remainder.zero? ? 0 : alignment - remainder
end

.parse(io, format: nil) ⇒ Entry

Parse entry from binary data

Parameters:

  • io (IO) —

    Input stream

  • format (Symbol, nil) (defaults to: nil) —

    Format hint (:newc, :crc, :odc, nil=auto-detect)

Returns:

  • (Entry) —

    Parsed entry



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# File 'lib/omnizip/formats/cpio/entry.rb', line 216

def self.parse(io, format: nil)
  # Read magic to detect format
  magic = io.read(6)
  io.seek(-6, ::IO::SEEK_CUR) # Rewind

  format ||= detect_format(magic)

  case format
  when :newc, :crc
    parse_newc(io)
  when :odc
    parse_odc(io)
  else
    raise "Unknown CPIO format"
  end
end

.parse_newc(io) ⇒ Entry

Parse newc format entry

Parameters:

  • io (IO) —

    Input stream

Returns:

  • (Entry) —

    Parsed entry



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# File 'lib/omnizip/formats/cpio/entry.rb', line 253

def self.parse_newc(io)
  header = io.read(NEWC_HEADER_SIZE)
  raise "Truncated CPIO header" unless header && header.bytesize == NEWC_HEADER_SIZE

  # Parse ASCII hex fields
  magic = header[0, 6]
  ino = header[6, 8].to_i(16)
  mode = header[14, 8].to_i(16)
  uid = header[22, 8].to_i(16)
  gid = header[30, 8].to_i(16)
  nlink = header[38, 8].to_i(16)
  mtime = header[46, 8].to_i(16)
  filesize = header[54, 8].to_i(16)
  dev_major = header[62, 8].to_i(16)
  dev_minor = header[70, 8].to_i(16)
  rdev_major = header[78, 8].to_i(16)
  rdev_minor = header[86, 8].to_i(16)
  namesize = header[94, 8].to_i(16)
  checksum = header[102, 8].to_i(16)

  # Read filename
  name_data = io.read(namesize)
  name = name_data.chomp("\x00")

  # Skip padding to 4-byte boundary
  header_name_size = NEWC_HEADER_SIZE + namesize
  padding = padding_to_align(header_name_size, NEWC_ALIGNMENT)
  io.read(padding) if padding.positive?

  # Read file data
  data = io.read(filesize)

  # Skip padding to 4-byte boundary
  data_padding = padding_to_align(filesize, NEWC_ALIGNMENT)
  io.read(data_padding) if data_padding.positive?

  new(
    magic: magic,
    ino: ino,
    mode: mode,
    uid: uid,
    gid: gid,
    nlink: nlink,
    mtime: mtime,
    filesize: filesize,
    dev_major: dev_major,
    dev_minor: dev_minor,
    rdev_major: rdev_major,
    rdev_minor: rdev_minor,
    namesize: namesize,
    checksum: checksum,
    name: name,
    data: data || "",
  )
end

.parse_odc(io) ⇒ Entry

Parse ODC format entry

Parameters:

  • io (IO) —

    Input stream

Returns:

  • (Entry) —

    Parsed entry



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# File 'lib/omnizip/formats/cpio/entry.rb', line 313

def self.parse_odc(io)
  header = io.read(76)
  raise "Truncated CPIO header" unless header && header.bytesize == 76

  # Parse octal fields
  magic = header[0, 6]
  dev = header[6, 6].to_i(8)
  ino = header[12, 6].to_i(8)
  mode = header[18, 6].to_i(8)
  uid = header[24, 6].to_i(8)
  gid = header[30, 6].to_i(8)
  nlink = header[36, 6].to_i(8)
  rdev = header[42, 6].to_i(8)
  mtime = header[48, 11].to_i(8)
  namesize = header[59, 6].to_i(8)
  filesize = header[65, 11].to_i(8)

  # Extract device numbers
  dev_major = dev >> 8
  dev_minor = dev & 0xFF
  rdev_major = rdev >> 8
  rdev_minor = rdev & 0xFF

  # Read filename
  name_data = io.read(namesize)
  name = name_data.chomp("\x00")

  # Read file data
  data = io.read(filesize)

  new(
    magic: magic,
    ino: ino,
    mode: mode,
    uid: uid,
    gid: gid,
    nlink: nlink,
    mtime: mtime,
    filesize: filesize,
    dev_major: dev_major,
    dev_minor: dev_minor,
    rdev_major: rdev_major,
    rdev_minor: rdev_minor,
    namesize: namesize,
    checksum: 0,
    name: name,
    data: data || "",
  )
end

Instance Method Details

#device? ⇒ Boolean

Check if entry is a device

Returns:

  • (Boolean) —

    true if device (block or character)



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# File 'lib/omnizip/formats/cpio/entry.rb', line 111

def device?
  type = @mode & S_IFMT
  [S_IFBLK, S_IFCHR].include?(type)
end

#directory? ⇒ Boolean

Check if entry is a directory

Returns:

  • (Boolean) —

    true if directory



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# File 'lib/omnizip/formats/cpio/entry.rb', line 90

def directory?
  (@mode & S_IFMT) == S_IFDIR
end

#file? ⇒ Boolean

Check if entry is a regular file

Returns:

  • (Boolean) —

    true if regular file



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# File 'lib/omnizip/formats/cpio/entry.rb', line 97

def file?
  (@mode & S_IFMT) == S_IFREG
end

#symlink? ⇒ Boolean

Check if entry is a symbolic link

Returns:

  • (Boolean) —

    true if symlink



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# File 'lib/omnizip/formats/cpio/entry.rb', line 104

def symlink?
  (@mode & S_IFMT) == S_IFLNK
end

#to_binary(format: :newc) ⇒ String

Convert entry to binary format

Parameters:

  • format (Symbol) (defaults to: :newc) —

    CPIO format (:newc, :crc, :odc)

Returns:

  • (String) —

    Binary representation



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# File 'lib/omnizip/formats/cpio/entry.rb', line 127

def to_binary(format: :newc)
  case format
  when :newc, :crc
    to_newc_binary
  when :odc
    to_odc_binary
  else
    raise ArgumentError, "Unsupported CPIO format: #{format}"
  end
end

#to_newc_binary ⇒ String

Convert to newc format binary

Returns:

  • (String) —

    Binary data in newc format



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# File 'lib/omnizip/formats/cpio/entry.rb', line 141

def to_newc_binary
  # Build header (110 bytes, ASCII hex)
  header = format(
    "%06s%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x",
    @magic,
    @ino & 0xFFFFFFFF,
    @mode & 0xFFFFFFFF,
    @uid & 0xFFFFFFFF,
    @gid & 0xFFFFFFFF,
    @nlink & 0xFFFFFFFF,
    @mtime & 0xFFFFFFFF,
    @filesize & 0xFFFFFFFF,
    @dev_major & 0xFFFFFFFF,
    @dev_minor & 0xFFFFFFFF,
    @rdev_major & 0xFFFFFFFF,
    @rdev_minor & 0xFFFFFFFF,
    @namesize & 0xFFFFFFFF,
    @checksum & 0xFFFFFFFF,
  )

  # Assemble complete entry
  result = +""
  result << header
  result << @name
  result << "\x00"

  # Pad header+name to 4-byte boundary
  header_name_size = header.bytesize + @name.bytesize + 1
  padding = padding_to_align(header_name_size, NEWC_ALIGNMENT)
  result << ("\x00" * padding) if padding.positive?

  # Add file data
  result << @data

  # Pad data to 4-byte boundary
  data_padding = padding_to_align(@data.bytesize, NEWC_ALIGNMENT)
  result << ("\x00" * data_padding) if data_padding.positive?

  result
end

#to_odc_binary ⇒ String

Convert to ODC format binary

Returns:

  • (String) —

    Binary data in ODC format



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# File 'lib/omnizip/formats/cpio/entry.rb', line 185

def to_odc_binary
  # ODC format uses 6-character octal fields
  header = format(
    "%06o%06o%06o%06o%06o%06o%06o%06o%011o%06o%011o",
    MAGIC_BINARY,
    (@dev_major << 8) | @dev_minor,
    @ino & 0o777777,
    @mode & 0o777777,
    @uid & 0o777777,
    @gid & 0o777777,
    @nlink & 0o777777,
    (@rdev_major << 8) | @rdev_minor,
    @mtime & 0o77777777777,
    @namesize & 0o777777,
    @filesize & 0o77777777777,
  )

  result = +""
  result << header
  result << @name
  result << "\x00"
  result << @data

  result
end

#trailer? ⇒ Boolean

Check if entry is the trailer

Returns:

  • (Boolean) —

    true if trailer entry



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# File 'lib/omnizip/formats/cpio/entry.rb', line 119

def trailer?
  @name == TRAILER_NAME
end