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# -*- coding: binary -*-
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require 'timeout'
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require 'thread'
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module Rex
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module Post
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module Meterpreter
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###
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#
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# This class handles waiting for a response to a given request
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# and the subsequent response association.
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#
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###
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class PacketResponseWaiter
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  # Arbitrary argument to {#completion_routine}
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  #
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  # @return [Object,nil]
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  attr_accessor :completion_param
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  # A callback to be called when this waiter is notified of a packet's
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  # arrival. If not nil, this will be called with the response packet as first
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  # parameter and {#completion_param} as the second.
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  #
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  # @return [Proc,nil]
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  attr_accessor :completion_routine
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  # @return [ConditionVariable]
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  attr_accessor :cond
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  # @return [Mutex]
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  attr_accessor :mutex
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  # @return [Packet]
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  attr_accessor :response
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  # @return [Integer] request ID to wait for
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  attr_accessor :rid
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  #
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  # Initializes a response waiter instance for the supplied request
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  # identifier.
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  #
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  def initialize(rid, completion_routine = nil, completion_param = nil)
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    self.rid      = rid.dup
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    self.response = nil
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    if (completion_routine)
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      self.completion_routine = completion_routine
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      self.completion_param   = completion_param
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    else
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      self.mutex = Mutex.new
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      self.cond  = ConditionVariable.new
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    end
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  end
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  #
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  # Checks to see if this waiter instance is waiting for the supplied
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  # packet based on its request identifier.
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  #
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  def waiting_for?(packet)
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    return (packet.rid == rid)
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  end
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  #
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  # Notifies the waiter that the supplied response packet has arrived.
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  #
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  # @param response [Packet]
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  # @return [void]
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  def notify(response)
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    if (self.completion_routine)
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      self.response = response
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      self.completion_routine.call(response, self.completion_param)
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    else
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      self.mutex.synchronize do
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        self.response = response
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        self.cond.signal
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      end
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    end
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  end
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  #
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  # Wait for a given time interval for the response packet to arrive.
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  #
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  # @param interval [Integer,nil] number of seconds to wait, or nil to wait
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  #   forever
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  # @return [Packet,nil] the response, or nil if the interval elapsed before
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  #   receiving one
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  def wait(interval)
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    interval = nil if interval and interval == -1
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    self.mutex.synchronize do
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      if self.response.nil?
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        self.cond.wait(self.mutex, interval)
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      end
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    end
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    return self.response
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  end
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end
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end; end; end
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