mirror of
https://github.com/ruby/ruby.git
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246 lines
5.9 KiB
Ruby
246 lines
5.9 KiB
Ruby
# -*- coding: utf-8 -*-
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# frozen_string_literal: true
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#--
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# Copyright (C) 2004 Mauricio Julio Fernández Pradier
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# See LICENSE.txt for additional licensing information.
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#++
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##
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#--
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# struct tarfile_entry_posix {
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# char name[100]; # ASCII + (Z unless filled)
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# char mode[8]; # 0 padded, octal, null
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# char uid[8]; # ditto
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# char gid[8]; # ditto
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# char size[12]; # 0 padded, octal, null
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# char mtime[12]; # 0 padded, octal, null
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# char checksum[8]; # 0 padded, octal, null, space
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# char typeflag[1]; # file: "0" dir: "5"
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# char linkname[100]; # ASCII + (Z unless filled)
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# char magic[6]; # "ustar\0"
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# char version[2]; # "00"
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# char uname[32]; # ASCIIZ
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# char gname[32]; # ASCIIZ
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# char devmajor[8]; # 0 padded, octal, null
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# char devminor[8]; # o padded, octal, null
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# char prefix[155]; # ASCII + (Z unless filled)
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# };
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#++
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# A header for a tar file
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class Gem::Package::TarHeader
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##
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# Fields in the tar header
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FIELDS = [
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:checksum,
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:devmajor,
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:devminor,
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:gid,
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:gname,
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:linkname,
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:magic,
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:mode,
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:mtime,
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:name,
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:prefix,
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:size,
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:typeflag,
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:uid,
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:uname,
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:version,
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].freeze
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##
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# Pack format for a tar header
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PACK_FORMAT = 'a100' + # name
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'a8' + # mode
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'a8' + # uid
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'a8' + # gid
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'a12' + # size
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'a12' + # mtime
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'a7a' + # chksum
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'a' + # typeflag
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'a100' + # linkname
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'a6' + # magic
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'a2' + # version
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'a32' + # uname
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'a32' + # gname
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'a8' + # devmajor
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'a8' + # devminor
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'a155' # prefix
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##
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# Unpack format for a tar header
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UNPACK_FORMAT = 'A100' + # name
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'A8' + # mode
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'A8' + # uid
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'A8' + # gid
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'A12' + # size
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'A12' + # mtime
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'A8' + # checksum
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'A' + # typeflag
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'A100' + # linkname
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'A6' + # magic
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'A2' + # version
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'A32' + # uname
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'A32' + # gname
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'A8' + # devmajor
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'A8' + # devminor
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'A155' # prefix
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attr_reader(*FIELDS)
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EMPTY_HEADER = ("\0" * 512).freeze # :nodoc:
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##
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# Creates a tar header from IO +stream+
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def self.from(stream)
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header = stream.read 512
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empty = (EMPTY_HEADER == header)
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fields = header.unpack UNPACK_FORMAT
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new :name => fields.shift,
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:mode => strict_oct(fields.shift),
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:uid => oct_or_256based(fields.shift),
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:gid => oct_or_256based(fields.shift),
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:size => strict_oct(fields.shift),
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:mtime => strict_oct(fields.shift),
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:checksum => strict_oct(fields.shift),
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:typeflag => fields.shift,
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:linkname => fields.shift,
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:magic => fields.shift,
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:version => strict_oct(fields.shift),
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:uname => fields.shift,
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:gname => fields.shift,
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:devmajor => strict_oct(fields.shift),
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:devminor => strict_oct(fields.shift),
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:prefix => fields.shift,
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:empty => empty
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end
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def self.strict_oct(str)
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return str.strip.oct if str.strip =~ /\A[0-7]*\z/
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raise ArgumentError, "#{str.inspect} is not an octal string"
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end
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def self.oct_or_256based(str)
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# \x80 flags a positive 256-based number
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# \ff flags a negative 256-based number
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# In case we have a match, parse it as a signed binary value
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# in big-endian order, except that the high-order bit is ignored.
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return str.unpack('N2').last if str =~ /\A[\x80\xff]/n
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strict_oct(str)
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end
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##
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# Creates a new TarHeader using +vals+
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def initialize(vals)
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unless vals[:name] && vals[:size] && vals[:prefix] && vals[:mode]
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raise ArgumentError, ":name, :size, :prefix and :mode required"
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end
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vals[:uid] ||= 0
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vals[:gid] ||= 0
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vals[:mtime] ||= 0
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vals[:checksum] ||= ""
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vals[:typeflag] = "0" if vals[:typeflag].nil? || vals[:typeflag].empty?
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vals[:magic] ||= "ustar"
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vals[:version] ||= "00"
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vals[:uname] ||= "wheel"
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vals[:gname] ||= "wheel"
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vals[:devmajor] ||= 0
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vals[:devminor] ||= 0
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FIELDS.each do |name|
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instance_variable_set "@#{name}", vals[name]
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end
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@empty = vals[:empty]
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end
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##
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# Is the tar entry empty?
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def empty?
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@empty
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end
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def ==(other) # :nodoc:
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self.class === other and
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@checksum == other.checksum and
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@devmajor == other.devmajor and
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@devminor == other.devminor and
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@gid == other.gid and
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@gname == other.gname and
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@linkname == other.linkname and
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@magic == other.magic and
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@mode == other.mode and
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@mtime == other.mtime and
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@name == other.name and
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@prefix == other.prefix and
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@size == other.size and
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@typeflag == other.typeflag and
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@uid == other.uid and
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@uname == other.uname and
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@version == other.version
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end
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def to_s # :nodoc:
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update_checksum
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header
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end
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##
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# Updates the TarHeader's checksum
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def update_checksum
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header = header " " * 8
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@checksum = oct calculate_checksum(header), 6
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end
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private
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def calculate_checksum(header)
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header.unpack("C*").inject { |a, b| a + b }
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end
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def header(checksum = @checksum)
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header = [
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name,
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oct(mode, 7),
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oct(uid, 7),
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oct(gid, 7),
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oct(size, 11),
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oct(mtime, 11),
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checksum,
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" ",
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typeflag,
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linkname,
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magic,
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oct(version, 2),
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uname,
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gname,
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oct(devmajor, 7),
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oct(devminor, 7),
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prefix
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]
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header = header.pack PACK_FORMAT
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header << ("\0" * ((512 - header.size) % 512))
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end
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def oct(num, len)
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"%0#{len}o" % num
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end
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end
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