fgrehm/vagrant-lxc

module Vagrant
  module LXC
    class SudoWrapper
      # Include this so we can use `Subprocess` more easily.
      include Vagrant::Util::Retryable

      attr_reader :wrapper_path

      def self.dest_path
        "/usr/local/bin/vagrant-lxc-wrapper"
      end

      def initialize(privileged: true)
        @wrapper_path = Pathname.new(SudoWrapper.dest_path).exist? && SudoWrapper.dest_path || nil
        @privileged   = privileged
        @logger       = Log4r::Logger.new("vagrant::lxc::sudo_wrapper")
      end

      def run(*command)
        options = command.last.is_a?(Hash) ? command.last : {}

        # Avoid running LXC commands with a restrictive umask.
        # Otherwise disasters occur, like the container root directory
        # having permissions `rwxr-x---` which prevents the `vagrant`
        # user from accessing its own home directory; among other
        # problems, SSH cannot then read `authorized_keys`!
        old_mask = File.umask
        File.umask(old_mask & 022)  # allow all `r` and `x` bits

        begin
          if @privileged
            if @wrapper_path && !options[:no_wrapper]
              command.unshift @wrapper_path
              execute *(['sudo'] + command)
            else
              execute *(['sudo', '/usr/bin/env'] + command)
            end
          else
            execute *(['/usr/bin/env'] + command)
          end
        ensure
          File.umask(old_mask)
        end
      end

      private

      # TODO: Review code below this line, it was pretty much a copy and
      #       paste from VirtualBox base driver and has no tests
      def execute(*command, &block)
        # Get the options hash if it exists
        opts = {}
        opts = command.pop if command.last.is_a?(Hash)

        tries = 0
        tries = 3 if opts[:retryable]

        sleep = opts.fetch(:sleep, 1)

        # Variable to store our execution result
        r = nil

        retryable(:on => LXC::Errors::ExecuteError, :tries => tries, :sleep => sleep) do
          # Execute the command
          r = raw(*command, &block)

          # If the command was a failure, then raise an exception that is
          # nicely handled by Vagrant.
          if r.exit_code != 0
            if @interrupted
              raise LXC::Errors::SubprocessInterruptError, command.inspect
            else
              raise LXC::Errors::ExecuteError,
                command: command.inspect, stderr: r.stderr, stdout: r.stdout, exitcode: r.exit_code
            end
          end
        end

        # Return the output, making sure to replace any Windows-style
        # newlines with Unix-style.
        stdout = r.stdout.gsub("\r\n", "\n")
        if opts[:show_stderr]
          { :stdout => stdout, :stderr => r.stderr.gsub("\r\n", "\n") }
        else
          stdout
        end
      end

      def raw(*command, &block)
        int_callback = lambda do
          @interrupted = true
          @logger.info("Interrupted.")
        end

        # Append in the options for subprocess
        command << { :notify => [:stdout, :stderr] }

        Vagrant::Util::Busy.busy(int_callback) do
          Vagrant::Util::Subprocess.execute(*command, &block)
        end
      end
    end
  end
end