Module: Rex::Ui::Text::DispatcherShell

Includes:
Resource, Shell
Included in:
Msf::Ui::Console::Driver, Post::HWBridge::Ui::Console, Post::Meterpreter::Ui::Console
Defined in:
lib/rex/ui/text/dispatcher_shell.rb

Overview

The dispatcher shell class is designed to provide a generic means of processing various shell commands that may be located in different modules or chunks of codes. These chunks are referred to as command dispatchers. The only requirement for command dispatchers is that they prefix every method that they wish to be mirrored as a command with the cmd_ prefix.

Defined Under Namespace

Modules: CommandDispatcher

Instance Attribute Summary collapse

Attributes included from Shell

#cont_flag, #cont_prompt, #disable_output, #framework, #hist_last_saved, #histfile, #input, #local_hostname, #local_username, #log_source, #name, #on_command_proc, #on_print_proc, #output, #prompt, #prompt_char, #stop_count, #stop_flag, #tab_complete_proc

Instance Method Summary collapse

Methods included from Shell

#_print_prompt, #format_prompt, #get_input_line, #init_tab_complete, #init_ui, #log_input, #log_output, #parse_line, #print, #print_error, #print_good, #print_line, #print_status, #print_warning, #prompt_yesno, #reset_ui, #run, #set_log_source, #stop, #stopped?, #supports_color?, #unset_log_source, #update_prompt

Methods included from Resource

#load_resource

Instance Attribute Details

#blockedObject

:nodoc:



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 719

def blocked
  @blocked
end

#busyObject

:nodoc:



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 718

def busy
  @busy
end

#dispatcher_stackObject

:nodoc:



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 717

def dispatcher_stack
  @dispatcher_stack
end

Instance Method Details

#append_dispatcher(dispatcher) ⇒ Object

Adds the supplied dispatcher to the end of the dispatcher stack so that it doesn't affect any enstack'd dispatchers.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 614

def append_dispatcher(dispatcher)
  inst = dispatcher.new(self)
  self.dispatcher_stack.each { |disp|
    if (disp.name == inst.name)
      raise "Attempting to load already loaded dispatcher #{disp.name}"
    end
  }
  self.dispatcher_stack.push(inst)

  inst
end

#block_command(cmd) ⇒ Object

Block a specific command



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 670

def block_command(cmd)
  self.blocked ||= {}
  self.blocked[cmd] = true
end

#blocked_command?(cmd) ⇒ Boolean

Returns nil for an empty set of blocked commands.

Returns:

  • (Boolean)


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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 662

def blocked_command?(cmd)
  return false if not self.blocked
  self.blocked.has_key?(cmd)
end

#current_dispatcherObject

Returns the current active dispatcher



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 638

def current_dispatcher
  self.dispatcher_stack[0]
end

#destack_dispatcherObject

Pop a dispatcher from the front of the stacker.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 606

def destack_dispatcher
  self.dispatcher_stack.shift
end

#enstack_dispatcher(dispatcher) ⇒ Object

Push a dispatcher to the front of the stack.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 597

def enstack_dispatcher(dispatcher)
  self.dispatcher_stack.unshift(inst = dispatcher.new(self))

  inst
end

#help_to_s(opts = {}) ⇒ Object

Return a readable version of a help banner for all of the enstacked dispatchers.

See CommandDispatcher#help_to_s



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 648

def help_to_s(opts = {})
  str = ''

  dispatcher_stack.reverse.each { |dispatcher|
    str << dispatcher.help_to_s
  }

  return str
end

#initialize(prompt, prompt_char = '>', histfile = nil, framework = nil, name = nil) ⇒ Object

Initialize the dispatcher shell.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 393

def initialize(prompt, prompt_char = '>', histfile = nil, framework = nil, name = nil)
  super

  # Initialze the dispatcher array
  self.dispatcher_stack = []

  # Initialize the tab completion array
  self.on_command_proc = nil
end

#remove_dispatcher(name) ⇒ Object

Removes the supplied dispatcher instance.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 629

def remove_dispatcher(name)
  self.dispatcher_stack.delete_if { |inst|
    (inst.name == name)
  }
end

#run_command(dispatcher, method, arguments) ⇒ Object

Runs the supplied command on the given dispatcher.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 575

def run_command(dispatcher, method, arguments)
  self.busy = true

  if(blocked_command?(method))
    print_error("The #{method} command has been disabled.")
  else
    dispatcher.send('cmd_' + method, *arguments)
  end
ensure
  self.busy = false
end

#run_single(line, propagate_errors: false) ⇒ Boolean

Run a single command line.

Parameters:

  • line (String)

    The command string that should be executed.

  • propagate_errors (Boolean) (defaults to: false)

    Whether or not to raise exceptions that are caught while executing the command.

Returns:

  • (Boolean)

    A boolean value signifying whether or not the command was handled. Value is `true` when the command line was handled.



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 512

def run_single(line, propagate_errors: false)
  arguments  = parse_line(line)
  method     = arguments.shift
  cmd_status = nil  # currently either nil or :handled, more statuses can be added in the future
  error      = false

  # If output is disabled output will be nil
  output.reset_color if (output)

  if (method)
    entries = dispatcher_stack.length

    dispatcher_stack.each { |dispatcher|
      next if not dispatcher.respond_to?('commands')

      begin
        if (dispatcher.commands.has_key?(method) or dispatcher.deprecated_commands.include?(method))
          self.on_command_proc.call(line.strip) if self.on_command_proc
          run_command(dispatcher, method, arguments)
          cmd_status = :handled
        elsif cmd_status.nil?
          cmd_status = dispatcher.unknown_command(method, line)
        end
      rescue ::Interrupt
        cmd_status = :handled
        print_error("#{method}: Interrupted")
        raise if propagate_errors
      rescue OptionParser::ParseError => e
        print_error("#{method}: #{e.message}")
        raise if propagate_errors
      rescue
        error = $!

        print_error(
          "Error while running command #{method}: #{$!}" +
          "\n\nCall stack:\n#{$@.join("\n")}")

        raise if propagate_errors
      rescue ::Exception => e
        error = $!

        print_error(
          "Error while running command #{method}: #{$!}")

        raise if propagate_errors
      end

      # If the dispatcher stack changed as a result of this command,
      # break out
      break if (dispatcher_stack.length != entries)
    }

    if (cmd_status.nil? && error == false)
      unknown_command(method, line)
    end
  end

  return cmd_status == :handled
end

#shellsplitex(line) ⇒ Object

Split a line as Shellwords.split would however instead of raising an ArgumentError on unbalanced quotes return the remainder of the string as if the last character were the closing quote.

This code was originally taken from github.com/ruby/ruby/blob/93420d34aaf8c30f11a66dd08eb186da922c831d/lib/shellwords.rb#L88



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 690

def shellsplitex(line)
  tokens = []
  field_value = String.new
  field_begin = nil

  line.scan(/\G(\s*)(?>([^\s\\\'\"]+)|'([^\']*)'|"((?:[^\"\\]|\\.)*)"|(\\.?)|(\S))(\s|\z)?/m) do |preceding_whitespace, word, sq, dq, esc, garbage, sep|
    field_begin ||= Regexp.last_match.begin(0) + preceding_whitespace.length
    if garbage
      quote_start_begin = Regexp.last_match.begin(0) + preceding_whitespace.length
      field_quote = garbage
      field_value << line[quote_start_begin + 1..-1].gsub('\\\\', '\\')

      tokens << { begin: field_begin, value: field_value, quote: field_quote }
      break
    end

    field_value << (word || sq || (dq && dq.gsub(/\\([$`"\\\n])/, '\\1')) || esc.gsub(/\\(.)/, '\\1'))
    if sep
      tokens << { begin: field_begin, value: field_value, quote: ((sq && "'") || (dq && '"') || nil) }
      field_value = String.new
      field_begin = nil
    end
  end

  { tokens: tokens }
end

#tab_complete(str) ⇒ Object

This method accepts the entire line of text from the Readline routine, stores all completed words, and passes the partial word to the real tab completion function. This works around a design problem in the Readline module and depends on the Readline.basic_word_break_characters variable being set to x00



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 410

def tab_complete(str)
  ::Readline.completion_append_character = ' '
  ::Readline.completion_case_fold = false

  # Check trailing whitespace so we can tell 'x' from 'x '
  str_match = str.match(/[^\\]([\\]{2})*\s+$/)
  str_trail = (str_match.nil?) ? '' : str_match[0]

  # Split the line up by whitespace into words
  split_str = shellsplitex(str)

  # Append an empty token if we had trailing whitespace
  split_str[:tokens] << { begin: str.length, value: '' } if str_trail.length > 0

  # Pop the last word and pass it to the real method
  result = tab_complete_stub(str, split_str)
  if result
    result.uniq
  else
    result
  end
end

#tab_complete_helper(dispatcher, str, words) ⇒ Object

Provide command-specific tab completion



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 491

def tab_complete_helper(dispatcher, str, words)
  tabs_meth = "cmd_#{words[0]}_tabs"
  # Is the user trying to tab complete one of our commands?
  if dispatcher.commands.include?(words[0]) and dispatcher.respond_to?(tabs_meth)
    res = dispatcher.send(tabs_meth, str, words)
    return [] if res.nil?
    return res
  end

  # Avoid the default completion list for unknown commands
  []
end

#tab_complete_stub(original_str, split_str) ⇒ Object

Performs tab completion of a command, if supported



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 435

def tab_complete_stub(original_str, split_str)
  *preceding_tokens, current_token = split_str[:tokens]
  return nil unless current_token

  items = []
  current_word = current_token[:value]
  tab_words = preceding_tokens.map { |word| word[:value] }

  # Next, try to match internal command or value completion
  # Enumerate each entry in the dispatcher stack
  dispatcher_stack.each do |dispatcher|

    # If no command is set and it supports commands, add them all
    if tab_words.empty? and dispatcher.respond_to?('commands')
      items.concat(dispatcher.commands.keys)
    end

    # If the dispatcher exports a tab completion function, use it
    if dispatcher.respond_to?('tab_complete_helper')
      res = dispatcher.tab_complete_helper(current_word, tab_words)
    else
      res = tab_complete_helper(dispatcher, current_word, tab_words)
    end

    if res.nil?
      # A nil response indicates no optional arguments
      return [''] if items.empty?
    else
      if res.second == :override_completions
        return res.first
      else
        # Otherwise we add the completion items to the list
        items.concat(res)
      end
    end
  end

  # Match based on the partial word
  matches = items.select do |word|
    word.downcase.start_with?(current_word.downcase)
  end

  # Prepend the preceding string of the command (or it all gets replaced!)
  preceding_str = original_str[0...current_token[:begin]]
  quote = current_token[:quote]
  matches_with_preceding_words_appended = matches.map do |word|
    word = quote.nil? ? word.gsub('\\') { '\\\\' }.gsub(' ', '\\ ') : "#{quote}#{word}#{quote}"
    preceding_str + word
  end

  matches_with_preceding_words_appended
end

#unblock_command(cmd) ⇒ Object

Unblock a specific command



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 678

def unblock_command(cmd)
  self.blocked || return
  self.blocked.delete(cmd)
end

#unknown_command(method, line) ⇒ Object

If the command is unknown…



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# File 'lib/rex/ui/text/dispatcher_shell.rb', line 590

def unknown_command(method, line)
  print_error("Unknown command: #{method}")
end