# -*- 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+.
def add_contents tar # :nodoc:
digests = tar.add_file_signed 'data.tar.gz', 0444, @signer do |io|
gzip_to io do |gz_io|
Gem::Package::TarWriter.new gz_io do |data_tar|
add_files data_tar
end
end
end
@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
FileUtils.mkdir_p File.dirname destination
open destination, 'wb', entry.header.mode do |out|
out.write entry.read
end
say destination if Gem.configuration.really_verbose
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 = File.realpath destination_dir if
File.respond_to? :realpath
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
##
# 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
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
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'
