class CrashWatch::App

def run(argv)
  options = {}
  parser = OptionParser.new do |opts|
    opts.banner = "Usage: crash-watch [options] PID"
    opts.separator ""
    opts.separator "Options:"
    opts.on("-d", "--debug", "Show GDB commands that crash-watch sends.") do
      options[:debug] = true
    end
    opts.on("--dump", "Dump current process backtrace and exit immediately.") do
      options[:dump] = true
    end
    opts.on("-v", "--version", "Show version number.") do
      options[:version] = true
    end
    opts.on("-h", "--help", "Show this help message.") do
      options[:help] = true
    end
  end
  begin
    parser.parse!(argv)
  rescue OptionParser::ParseError => e
    puts e
    puts
    puts "Please see '--help' for valid options."
    exit 1
  end
  if options[:help]
    puts parser
    exit
  elsif options[:version]
    puts "crash-watch version #{CrashWatch::VERSION_STRING}"
    exit
  elsif argv.size != 1
    puts parser
    exit 1
  end
  begin
    gdb = CrashWatch::GdbController.new
  rescue CrashWatch::Error => e
    abort e.message
  end
  begin
    gdb.debug = options[:debug]
    # Ruby sometimes uses SIGVTARLM for thread scheduling.
    gdb.execute("handle SIGVTALRM noprint pass")
    if gdb.attach(argv[0])
      if options[:dump]
        puts "*******************************************************"
        puts "*"
        puts "*    Current thread (#{gdb.current_thread}) backtrace"
        puts "*"
        puts "*******************************************************"
        puts
        puts "    " << gdb.current_thread_backtrace.gsub(/\n/, "\n    ")
        puts
        puts
        puts "*******************************************************"
        puts "*"
        puts "*    All thread backtraces"
        puts "*"
        puts "*******************************************************"
        puts
        output = gdb.all_threads_backtraces
        output.gsub!(/\n/, "\n    ")
        output.insert(0, "    ")
        output.gsub!(/^    (Thread .*):$/, "########### \\1 ###########\n")
        puts output
      else
        puts "Monitoring PID #{argv[0]}..."
        exit_info = gdb.wait_until_exit
        puts "Process exited at #{Time.now}."
        puts "Exit code: #{exit_info.exit_code}" if exit_info.exit_code
        puts "Signal: #{exit_info.signal}" if exit_info.signaled?
        if exit_info.backtrace
          puts "Backtrace:"
          puts "    " << exit_info.backtrace.gsub(/\n/, "\n    ")
        end
      end
    else
      puts "ERROR: Cannot attach to process."
      if File.exist?("/proc/sys/kernel/yama/ptrace_scope")
        puts
        puts "This may be the result of kernel ptrace() hardening. Try disabling it with:"
        puts "  sudo sh -c 'echo 0 > /proc/sys/kernel/yama/ptrace_scope'"
        puts "See http://askubuntu.com/questions/41629/after-upgrade-gdb-wont-attach-to-process for more information."
      end
      exit 2
    end
  ensure
    gdb.close
  end
end