text: #!/usr/local/bin/python2.7
  
  """
      Copyright (c) 2015-2018 Ad Schellevis <ad@opnsense.org>
      All rights reserved.
  
      Redistribution and use in source and binary forms, with or without
      modification, are permitted provided that the following conditions are met:
  
      1. Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.
  
      2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
  
      THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
      INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
      AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
      AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
      OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
      SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
      INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
      CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
      ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
      POSSIBILITY OF SUCH DAMAGE.
  
      --------------------------------------------------------------------------------------
  
      update/download suricata rules
  """
  
  import os
  import sys
  import syslog
  import fcntl
  from ConfigParser import ConfigParser
  from lib import metadata
  from lib import downloader
  from lib import rule_source_directory
  
  # check for a running update process, this may take a while so it's better to check...
  try:
      lck = open('/tmp/suricata-rule-updater.py', 'w+')
      fcntl.flock(lck, fcntl.LOCK_EX | fcntl.LOCK_NB)
  except IOError:
      # already running, exit status 99
      sys.exit(99)
  
  if __name__ == '__main__':
      # load list of configured rules from generated config
      enabled_rulefiles = dict()
      rule_properties = dict()
      metadata_sources = dict()
      updater_conf = '/usr/local/etc/suricata/rule-updater.config'
      if os.path.exists(updater_conf):
          cnf = ConfigParser()
          cnf.read(updater_conf)
          for section in cnf.sections():
              if section == '__properties__':
                  # special section, rule properties (extend url's etc.)
                  for item in cnf.items(section):
                      rule_properties[item[0]] = item[1]
              elif cnf.has_option(section, 'enabled') and cnf.getint(section, 'enabled') == 1:
                  enabled_rulefiles[section.strip()] = {}
                  # input filter
                  if cnf.has_option(section, 'filter'):
                      enabled_rulefiles[section.strip()]['filter'] = cnf.get(section, 'filter').strip()
                  else:
                      enabled_rulefiles[section.strip()]['filter'] = ""
  
      # download / remove rules
      md = metadata.Metadata()
      dl = downloader.Downloader(target_dir=rule_source_directory)
      for rule in md.list_rules(rule_properties):
          if rule['metadata_source'] not in metadata_sources:
              metadata_sources[rule['metadata_source']] = 0
          if 'url' in rule['source']:
              if dl.is_supported(url=rule['source']['url']):
                  if rule['required'] and metadata_sources[rule['metadata_source']] > 0:
                      # Required files are always sorted last in list_rules(), add required when there's at least one
                      # file selected from the metadata package.
                      enabled_rulefiles[rule['filename']] = {'filter': ''}
                  if rule['filename'] not in enabled_rulefiles:
                      full_path = ('%s/%s' % (rule_source_directory, rule['filename'])).replace('//', '/')
                      if os.path.isfile(full_path):
                          os.remove(full_path)
                  else:
                      input_filter = enabled_rulefiles[rule['filename']]['filter']
                      if ('username' in rule['source'] and 'password' in rule['source']):
                          auth = (rule['source']['username'], rule['source']['password'])
                      else:
                          auth = None
                      # when metadata supports versioning, check if either version or settings changed before download
                      remote_hash = dl.fetch_version_hash(check_url=rule['version_url'], input_filter=input_filter,
                                                          auth=auth, headers=rule['http_headers'])
                      local_hash = dl.installed_file_hash(rule['filename'])
                      if remote_hash is None or remote_hash != local_hash:
                          dl.download(url=rule['url'], url_filename=rule['url_filename'],
                                      filename=rule['filename'], input_filter=input_filter, auth=auth,
                                      headers=rule['http_headers'], version=remote_hash)
                          # count number of downloaded files/rules from this metadata package
                          metadata_sources[rule['metadata_source']] += 1
                      else:
                          syslog.syslog(syslog.LOG_INFO, 'download skipped %s, same version' % rule['filename'])
  
      # cleanup: match all installed rulesets against the configured ones and remove uninstalled rules
      md_filenames = map(lambda x:x['filename'], md.list_rules(rule_properties))
      for filename in enabled_rulefiles:
          full_path = ('%s/%s' % (rule_source_directory, filename)).replace('//', '/')
          if filename not in md_filenames and os.path.isfile(full_path):
              os.remove(full_path)
  