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Editing File: /usr/share/rubygems/rubygems/package.rb

# -*- coding: utf-8 -*-
#--
# Copyright (C) 2004 Mauricio Julio Fernández Pradier
# See LICENSE.txt for additional licensing information.
#++
#
# Example using a Gem::Package
#
# Builds a .gem file given a Gem::Specification. A .gem file is a tarball
# which contains a data.tar.gz and metadata.gz, and possibly signatures.
#
#   require 'rubygems'
#   require 'rubygems/package'
#
#   spec = Gem::Specification.new do |s|
#     s.summary = "Ruby based make-like utility."
#     s.name = 'rake'
#     s.version = PKG_VERSION
#     s.requirements << 'none'
#     s.files = PKG_FILES
#     s.description = <<-EOF
#   Rake is a Make-like program implemented in Ruby. Tasks
#   and dependencies are specified in standard Ruby syntax.
#     EOF
#   end
#
#   Gem::Package.build spec
#
# Reads a .gem file.
#
#   require 'rubygems'
#   require 'rubygems/package'
#
#   the_gem = Gem::Package.new(path_to_dot_gem)
#   the_gem.contents # get the files in the gem
#   the_gem.extract_files destination_directory # extract the gem into a directory
#   the_gem.spec # get the spec out of the gem
#   the_gem.verify # check the gem is OK (contains valid gem specification, contains a not corrupt contents archive)
#
# #files are the files in the .gem tar file, not the ruby files in the gem
# #extract_files and #contents automatically call #verify

require 'rubygems/security'
require 'rubygems/specification'
require 'rubygems/user_interaction'
require 'zlib'

class Gem::Package

include Gem::UserInteraction

class Error < Gem::Exception; end

class FormatError < Error
    attr_reader :path

def initialize message, path = nil
      @path = path

message << " in #{path}" if path

super message
    end

end

class PathError < Error
    def initialize destination, destination_dir
      super "installing into parent path %s of %s is not allowed" %
              [destination, destination_dir]
    end
  end

class NonSeekableIO < Error; end

class TooLongFileName < Error; end

##
  # Raised when a tar file is corrupt

class TarInvalidError < Error; end

attr_accessor :build_time # :nodoc:

##
  # Checksums for the contents of the package

attr_reader :checksums

##
  # The files in this package.  This is not the contents of the gem, just the
  # files in the top-level container.

attr_reader :files

##
  # The security policy used for verifying the contents of this package.

attr_accessor :security_policy

##
  # Sets the Gem::Specification to use to build this package.

attr_writer :spec

def self.build spec, skip_validation=false
    gem_file = spec.file_name

package = new gem_file
    package.spec = spec
    package.build skip_validation

gem_file
  end

##
  # Creates a new Gem::Package for the file at +gem+.
  #
  # If +gem+ is an existing file in the old format a Gem::Package::Old will be
  # returned.

def self.new gem
    return super unless Gem::Package == self
    return super unless File.exist? gem

start = File.read gem, 20

return super unless start
    return super unless start.include? 'MD5SUM ='

Gem::Package::Old.new gem
  end

##
  # Creates a new package that will read or write to the file +gem+.

def initialize gem # :notnew:
    @gem = gem

@build_time      = Time.now
    @checksums       = {}
    @contents        = nil
    @digests         = Hash.new { |h, algorithm| h[algorithm] = {} }
    @files           = nil
    @security_policy = nil
    @signatures      = {}
    @signer          = nil
    @spec            = nil
  end

##
  # Adds a checksum for each entry in the gem to checksums.yaml.gz.

def add_checksums tar
    Gem.load_yaml

checksums_by_algorithm = Hash.new { |h, algorithm| h[algorithm] = {} }

@checksums.each do |name, digests|
      digests.each do |algorithm, digest|
        checksums_by_algorithm[algorithm][name] = digest.hexdigest
      end
    end

tar.add_file_signed 'checksums.yaml.gz', 0444, @signer do |io|
      gzip_to io do |gz_io|
        YAML.dump checksums_by_algorithm, gz_io
      end
    end
  end

##
  # Adds the files listed in the packages's Gem::Specification to data.tar.gz
  # and adds this file to the +tar+.

@checksums['data.tar.gz'] = digests
  end

##
  # Adds files included the package's Gem::Specification to the +tar+ file

def add_files tar # :nodoc:
    @spec.files.each do |file|
      stat = File.stat file

next unless stat.file?

tar.add_file_simple file, stat.mode, stat.size do |dst_io|
        open file, 'rb' do |src_io|
          dst_io.write src_io.read 16384 until src_io.eof?
        end
      end
    end
  end

##
  # Adds the package's Gem::Specification to the +tar+ file

def add_metadata tar # :nodoc:
    digests = tar.add_file_signed 'metadata.gz', 0444, @signer do |io|
      gzip_to io do |gz_io|
        gz_io.write @spec.to_yaml
      end
    end

@checksums['metadata.gz'] = digests
  end

##
  # Builds this package based on the specification set by #spec=

def build skip_validation = false
    Gem.load_yaml
    require 'rubygems/security'

@spec.mark_version
    @spec.validate unless skip_validation

setup_signer

open @gem, 'wb' do |gem_io|
      Gem::Package::TarWriter.new gem_io do |gem|
        add_metadata gem
        add_contents gem
        add_checksums gem
      end
    end

say <<-EOM
  Successfully built RubyGem
  Name: #{@spec.name}
  Version: #{@spec.version}
  File: #{File.basename @spec.cache_file}
EOM
  ensure
    @signer = nil
  end

##
  # A list of file names contained in this gem

def contents
    return @contents if @contents

verify unless @spec

@contents = []

open @gem, 'rb' do |io|
      gem_tar = Gem::Package::TarReader.new io

gem_tar.each do |entry|
        next unless entry.full_name == 'data.tar.gz'

open_tar_gz entry do |pkg_tar|
          pkg_tar.each do |contents_entry|
            @contents << contents_entry.full_name
          end
        end

return @contents
      end
    end
  end

##
  # Creates a digest of the TarEntry +entry+ from the digest algorithm set by
  # the security policy.

def digest entry # :nodoc:
    algorithms = if @checksums then
                   @checksums.keys
                 else
                   [Gem::Security::DIGEST_NAME]
                 end

algorithms.each do |algorithm|
      digester = OpenSSL::Digest.new algorithm

digester << entry.read(16384) until entry.eof?

entry.rewind

@digests[algorithm][entry.full_name] = digester
    end

@digests
  end

##
  # Extracts the files in this package into +destination_dir+

def extract_files destination_dir
    verify unless @spec

FileUtils.mkdir_p destination_dir

open @gem, 'rb' do |io|
      reader = Gem::Package::TarReader.new io

reader.each do |entry|
        next unless entry.full_name == 'data.tar.gz'

extract_tar_gz entry, destination_dir

return # ignore further entries
      end
    end
  end

##
  # Extracts all the files in the gzipped tar archive +io+ into
  # +destination_dir+.
  #
  # If an entry in the archive contains a relative path above
  # +destination_dir+ or an absolute path is encountered an exception is
  # raised.

def extract_tar_gz io, destination_dir # :nodoc:
    open_tar_gz io do |tar|
      tar.each do |entry|
        destination = install_location entry.full_name, destination_dir

FileUtils.rm_rf destination

mkdir_options = {}
        mkdir_options[:mode] = entry.header.mode if entry.directory?
        mkdir =
          if entry.directory? then
            destination
          else
            File.dirname destination
          end

mkdir_p_safe mkdir, mkdir_options, destination_dir, entry.full_name

open destination, 'wb', entry.header.mode do |out|
          out.write entry.read
        end

verbose destination
      end
    end
  end

##
  # Gzips content written to +gz_io+ to +io+.
  #--
  # Also sets the gzip modification time to the package build time to ease
  # testing.

def gzip_to io # :yields: gz_io
    gz_io = Zlib::GzipWriter.new io, Zlib::BEST_COMPRESSION
    gz_io.mtime = @build_time

yield gz_io
  ensure
    gz_io.close
  end

##
  # Returns the full path for installing +filename+.
  #
  # If +filename+ is not inside +destination_dir+ an exception is raised.

def install_location filename, destination_dir # :nodoc:
    raise Gem::Package::PathError.new(filename, destination_dir) if
      filename.start_with? '/'

destination_dir = realpath destination_dir

destination = File.join destination_dir, filename
    destination = File.expand_path destination

raise Gem::Package::PathError.new(destination, destination_dir) unless
      destination.start_with? destination_dir + '/'

destination.untaint
    destination
  end

def mkdir_p_safe mkdir, mkdir_options, destination_dir, file_name
    destination_dir = realpath File.expand_path(destination_dir)
    parts = mkdir.split(File::SEPARATOR)
    parts.reduce do |path, basename|
      path = realpath path  unless path == ""
      path = File.expand_path(path + File::SEPARATOR + basename)
      lstat = File.lstat path rescue nil
      if !lstat || !lstat.directory?
        unless path.start_with? destination_dir and (FileUtils.mkdir path, mkdir_options rescue false)
          raise Gem::Package::PathError.new(file_name, destination_dir)
        end
      end
      path
    end
  end

##
  # Loads a Gem::Specification from the TarEntry +entry+

def load_spec entry # :nodoc:
    case entry.full_name
    when 'metadata' then
      @spec = Gem::Specification.from_yaml entry.read
    when 'metadata.gz' then
      args = [entry]
      args << { :external_encoding => Encoding::UTF_8 } if
        Object.const_defined?(:Encoding) &&
          Zlib::GzipReader.method(:wrap).arity != 1

Zlib::GzipReader.wrap(*args) do |gzio|
        @spec = Gem::Specification.from_yaml gzio.read
      end
    end
  end

##
  # Opens +io+ as a gzipped tar archive

def open_tar_gz io # :nodoc:
    Zlib::GzipReader.wrap io do |gzio|
      tar = Gem::Package::TarReader.new gzio

yield tar
    end
  end

##
  # Reads and loads checksums.yaml.gz from the tar file +gem+

def read_checksums gem
    Gem.load_yaml

@checksums = gem.seek 'checksums.yaml.gz' do |entry|
      Zlib::GzipReader.wrap entry do |gz_io|
        Gem::SafeYAML.safe_load gz_io.read
      end
    end
  end

##
  # Prepares the gem for signing and checksum generation.  If a signing
  # certificate and key are not present only checksum generation is set up.

def setup_signer
    if @spec.signing_key then
      @signer = Gem::Security::Signer.new @spec.signing_key, @spec.cert_chain
      @spec.signing_key = nil
      @spec.cert_chain = @signer.cert_chain.map { |cert| cert.to_s }
    else
      @signer = Gem::Security::Signer.new nil, nil
      @spec.cert_chain = @signer.cert_chain.map { |cert| cert.to_pem } if
        @signer.cert_chain
    end
  end

##
  # The spec for this gem.
  #
  # If this is a package for a built gem the spec is loaded from the
  # gem and returned.  If this is a package for a gem being built the provided
  # spec is returned.

def spec
    verify unless @spec

@spec
  end

##
  # Verifies that this gem:
  #
  # * Contains a valid gem specification
  # * Contains a contents archive
  # * The contents archive is not corrupt
  #
  # After verification the gem specification from the gem is available from
  # #spec

def verify
    @files     = []
    @spec      = nil

open @gem, 'rb' do |io|
      Gem::Package::TarReader.new io do |reader|
        read_checksums reader

verify_files reader
      end
    end

verify_checksums @digests, @checksums

@security_policy.verify_signatures @spec, @digests, @signatures if
      @security_policy

true
  rescue Gem::Security::Exception
    @spec = nil
    @files = []
    raise
  rescue Errno::ENOENT => e
    raise Gem::Package::FormatError.new e.message
  rescue Gem::Package::TarInvalidError => e
    raise Gem::Package::FormatError.new e.message, @gem
  end

##
  # Verifies the +checksums+ against the +digests+.  This check is not
  # cryptographically secure.  Missing checksums are ignored.

def verify_checksums digests, checksums # :nodoc:
    return unless checksums

checksums.sort.each do |algorithm, gem_digests|
      gem_digests.sort.each do |file_name, gem_hexdigest|
        computed_digest = digests[algorithm][file_name]

unless computed_digest.hexdigest == gem_hexdigest then
          raise Gem::Package::FormatError.new \
            "#{algorithm} checksum mismatch for #{file_name}", @gem
        end
      end
    end
  end

##
  # Verifies the files of the +gem+

def verify_files gem
    gem.each do |entry|
      file_name = entry.full_name
      @files << file_name

case file_name
      when /\.sig$/ then
        @signatures[$`] = entry.read if @security_policy
        next
      else
        digest entry
      end

case file_name
      when /^metadata(.gz)?$/ then
        load_spec entry
      when 'data.tar.gz' then
        verify_gz entry
      end
    end

unless @spec then
      raise Gem::Package::FormatError.new 'package metadata is missing', @gem
    end

unless @files.include? 'data.tar.gz' then
      raise Gem::Package::FormatError.new \
              'package content (data.tar.gz) is missing', @gem
    end

if duplicates = @files.group_by {|f| f }.select {|k,v| v.size > 1 }.map(&:first) and duplicates.any?
      raise Gem::Security::Exception, "duplicate files in the package: (#{duplicates.map(&:inspect).join(', ')})"
    end
  end

##
  # Verifies that +entry+ is a valid gzipped file.

def verify_gz entry # :nodoc:
    Zlib::GzipReader.wrap entry do |gzio|
      gzio.read 16384 until gzio.eof? # gzip checksum verification
    end
  rescue Zlib::GzipFile::Error => e
    raise Gem::Package::FormatError.new(e.message, entry.full_name)
  end

if File.respond_to? :realpath
    def realpath file
      File.realpath file
    end
  else
    def realpath file
      file
    end
  end

end

require 'rubygems/package/digest_io'
require 'rubygems/package/old'
require 'rubygems/package/tar_header'
require 'rubygems/package/tar_reader'
require 'rubygems/package/tar_reader/entry'
require 'rubygems/package/tar_writer'

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