Class: Hijack::Payload

Inherits:
Object
  • Object
show all
Defined in:
lib/hijack/payload.rb

Class Method Summary collapse

Class Method Details

.inject(pid) ⇒ Object 



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# File 'lib/hijack/payload.rb', line 3

def self.inject(pid)
  gdb = nil
  trap('SIGINT') do
    puts
    @received_sigint = true
  end
  gdb = GDB.new(pid)
  gdb.eval(payload(pid))
  gdb.detach
  exit if @received_sigint
end

.payload(pid) ⇒ Object 



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# File 'lib/hijack/payload.rb', line 15

def self.payload(pid)
  <<-RUBY
    require 'stringio'
    require 'drb'

    unless defined?(Hijack)
      module Hijack
        class OutputCopier
          def self.remote
            @remote
          end

          def self.stop
            @remote = nil
            [$stdout, $stderr].each do |io|
              if io.respond_to?(:write_with_copying)
                class << io
                  alias_method :write, :write_without_copying
                  remove_method :write_with_copying
                end
              end
            end
          end

          def self.start(pid)
            @remote = DRbObject.new(nil, 'drbunix://tmp/hijack.' + pid + '.sock')

            class << $stdout
              def write_with_copying(str)
                write_without_copying(str)
                begin
                  Hijack::OutputCopier.remote.write('stdout', str)
                rescue Exception
                  Hijack.stop
                end
              end
              alias_method :write_without_copying, :write
              alias_method :write, :write_with_copying
            end

            class << $stderr
              def write_with_copying(str)
                write_without_copying(str)
                begin
                  Hijack::OutputCopier.remote.write('stderr', str)
                rescue Exception
                  Hijack.stop
                end
              end
              alias_method :write_without_copying, :write
              alias_method :write, :write_with_copying
            end
          end
        end

        class Evaluator
          def initialize(context)
            @context = context
            @file = __FILE__
          end

          def evaluate(rb)
            if rb =~ /__hijack_output_receiver_ready_([\\d]+)/
              OutputCopier.start($1)
            elsif rb =~ /__hijack_get_remote_file_name/
              @file
            elsif rb =~ /__hijack_exit/
              Hijack.stop
            else
              @context.instance_eval(rb)
            end
          end
        end

        def self.start(context)
          return if @service && @service.alive?
          evaluator = Hijack::Evaluator.new(context)
          @service = DRb.start_service('#{Hijack.socket_for(pid)}', evaluator)
          File.chmod(0600, '#{Hijack.socket_path_for(pid)}')
        end

        def self.stop
          begin
            OutputCopier.stop
            @service.stop_service
            @service = nil
          rescue Exception
          end
        end
      end
    end
    Hijack.start(self)
  RUBY
end