old_contents: #!/usr/bin/python2 -O
  # vim: fileencoding=utf-8
  
  #
  # The Qubes OS Project, https://www.qubes-os.org/
  #
  # Copyright (C) 2015  Joanna Rutkowska <joanna@invisiblethingslab.com>
  # Copyright (C) 2015  Wojtek Porczyk <woju@invisiblethingslab.com>
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation; either version 2 of the License, or
  # (at your option) any later version.
  #
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License along
  # with this program; if not, write to the Free Software Foundation, Inc.,
  # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  #
  
  '''Qubes' command line tools
  '''
  
  import argparse
  import importlib
  
  
  # TODO --verbose, logger setup
  def get_parser_base(*args, **kwargs):
      '''Get base parser with options common to all Qubes OS tools.
  
      Currently supported options: ``--xml``.
  
      *args* and *kwargs* are passed to :py:class:`argparser.ArgumentParser`.
      '''
      parser = argparse.ArgumentParser(*args, **kwargs)
  
      parser.add_argument('--xml', metavar='XMLFILE',
          action='store',
          help='Qubes OS store file')
  
      return parser
  
  
  def get_parser_for_command(command):
      '''Get parser for given qvm-tool.
  
      :param str command: command name
      :rtype: argparse.ArgumentParser
      :raises ImportError: when command's module is not found
      :raises AttributeError: when parser was not found
      '''
  
      module = importlib.import_module(
          '.' + command.replace('-', '_'), 'qubes.tools')
  
      try:
          parser = module.parser
      except AttributeError:
          try:
              parser = module.get_parser()
          except AttributeError:
              raise AttributeError('cannot find parser in module')
  
      return parser
  
new_contents: #!/usr/bin/python2 -O
  # vim: fileencoding=utf-8
  
  #
  # The Qubes OS Project, https://www.qubes-os.org/
  #
  # Copyright (C) 2015  Joanna Rutkowska <joanna@invisiblethingslab.com>
  # Copyright (C) 2015  Wojtek Porczyk <woju@invisiblethingslab.com>
  #
  # This program is free software; you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation; either version 2 of the License, or
  # (at your option) any later version.
  #
  # This program is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License along
  # with this program; if not, write to the Free Software Foundation, Inc.,
  # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  #
  
  '''Qubes' command line tools
  '''
  
  import argparse
  import importlib
  import os
  
  
  # TODO --verbose, logger setup
  def get_parser_base(want_force_root=False, **kwargs):
      '''Get base parser with options common to all Qubes OS tools.
  
      :param bool want_force_root: add ``--force-root`` option
      *kwargs* are passed to :py:class:`argparser.ArgumentParser`.
  
      Currently supported options: ``--force-root`` (optional), ``--xml``.
      '''
      parser = argparse.ArgumentParser(**kwargs)
  
      parser.add_argument('--xml', metavar='XMLFILE',
          action='store',
          help='Qubes OS store file')
  
      if want_force_root:
          parser.add_argument('--force-root',
              action='store_true', default=False,
              help='Force to run as root.')
  
      return parser
  
  
  def get_parser_for_command(command):
      '''Get parser for given qvm-tool.
  
      :param str command: command name
      :rtype: argparse.ArgumentParser
      :raises ImportError: when command's module is not found
      :raises AttributeError: when parser was not found
      '''
  
      module = importlib.import_module(
          '.' + command.replace('-', '_'), 'qubes.tools')
  
      try:
          parser = module.parser
      except AttributeError:
          try:
              parser = module.get_parser()
          except AttributeError:
              raise AttributeError('cannot find parser in module')
  
      return parser
  
  
  def dont_run_as_root(parser, args):
      '''Prevent running as root.
  
      :param argparse.ArgumentParser parser: parser on which we invoke error
      :param argparse.Namespace args: if there is ``.force_root`` attribute set \
          to true, run anyway
      :return: If we should back off
      :rtype bool:
      '''
      try:
          euid = os.geteuid()
      except AttributeError: # no geteuid(), probably NT
          return
  
      if euid == 0 and not args.force_root:
          parser.error('refusing to run as root; add --force-root to override')
  
subject: add common --force-root option