metasploit-framework/tools/nasm_shell.rb

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#!/usr/bin/env ruby
#
# This tool provides an easy way to see what opcodes are associated with
# certain x86 instructions by making use of nasm if it is installed and
# reachable through the PATH environment variable.
#
$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
require 'rex'
require 'rex/ui'
# Check to make sure nasm is installed and reachable through the user's PATH.
begin
Rex::Assembly::Nasm.check
rescue RuntimeError
puts "#{$!}"
exit
end
# Start a pseudo shell and dispatch lines to be assembled and then
# disassembled.
shell = Rex::Ui::Text::PseudoShell.new("%bldnasm%clr")
shell.init_ui(Rex::Ui::Text::Input::Stdio.new, Rex::Ui::Text::Output::Stdio.new)
shell.run { |line|
line.gsub!(/(\r|\n)/, '')
line.gsub!(/\\n/, "\n")
break if (line =~ /^(exit|quit)/i)
begin
puts(Rex::Assembly::Nasm.disassemble(
Rex::Assembly::Nasm.assemble(line)))
rescue RuntimeError
puts "Error: #{$!}"
end
}