Contents

require 'daemons'

module FireAndForget
  module Command
    class Fire < CommandBase
      attr_reader :niceness, :task_uid, :task_gid

      def initialize(task, params={})
        super
        @task_uid = Process.euid
        @task_gid = Process.egid
      end

      def niceness
        @task.niceness
      end

      def binary
        @task.binary
      end

      def cmd
        %(#{binary} #{FireAndForget.to_arguments(@params)})
      end

      def valid?
        exists? && permitted?
      end

      def permitted?
        raise PermissionsError, "'#{binary}' does not belong to user '#{ENV["USER"]}'" unless File.stat(binary).uid == task_uid
        true
      end

      def exists?
        raise FileNotFoundError, "'#{binary}'" unless File.exists?(binary)
        true
      end

      def env
        @task.env.merge({
          FireAndForget::ENV_SOCKET => FireAndForget.socket,
          FireAndForget::ENV_TASK_NAME => @task.name.to_s
        })
      end

      def run
        if valid?
          pid = fork do
            # set up the environment so that the task can access the F&F server
            env.each { | k, v | ENV[k] = v }
            Daemons.daemonize(:backtrace => true)
            Process.setpriority(Process::PRIO_PROCESS, 0, niceness) if niceness > 0
            # change to the UID of the originating thread if necessary
            Process::UID.change_privilege(task_uid) unless Process.euid == task_uid
            exec(cmd)
          end
          Process.detach(pid) if pid
          # don't return the PID as it's actually wrong (the daemonize call forks again so our original
          # PID is at least 1 out)
          "OK"
        end
      end
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
fire_and_forget-0.2.0	lib/fire_and_forget/command/fire.rb