Synnefo » snf-ganeti

def _UpdateKnownHosts(fullnode, ip, pubkey):

  """Ensure a node has a correct known_hosts entry.

  Args:

    fullnode - Fully qualified domain name of host. (str)

    ip       - IPv4 address of host (str)

    pubkey   - the public key of the cluster

  """

  if os.path.exists(constants.SSH_KNOWN_HOSTS_FILE):

    f = open(constants.SSH_KNOWN_HOSTS_FILE, 'r+')

  else:

    f = open(constants.SSH_KNOWN_HOSTS_FILE, 'w+')

  inthere = False

  save_lines = []

  add_lines = []

  removed = False

  for rawline in f:

    logger.Debug('read %s' % (repr(rawline),))

    parts = rawline.rstrip('\r\n').split()

    # Ignore unwanted lines

    if len(parts) >= 3 and not rawline.lstrip()[0] == '#':

      fields = parts[0].split(',')

      key = parts[2]

      haveall = True

      havesome = False

      for spec in [ ip, fullnode ]:

        if spec not in fields:

          haveall = False

        if spec in fields:

          havesome = True

      logger.Debug("key, pubkey = %s." % (repr((key, pubkey)),))

      if haveall and key == pubkey:

        inthere = True

        save_lines.append(rawline)

        logger.Debug("Keeping known_hosts '%s'." % (repr(rawline),))

        continue

      if havesome and (not haveall or key != pubkey):

        removed = True

        logger.Debug("Discarding known_hosts '%s'." % (repr(rawline),))

        continue

    save_lines.append(rawline)

  if not inthere:

    add_lines.append('%s,%s ssh-rsa %s\n' % (fullnode, ip, pubkey))

    logger.Debug("Adding known_hosts '%s'." % (repr(add_lines[-1]),))

  if removed:

    save_lines = save_lines + add_lines

    # Write a new file and replace old.

    fd, tmpname = tempfile.mkstemp('.tmp', 'known_hosts.',

                                   constants.DATA_DIR)

    newfile = os.fdopen(fd, 'w')

    try:

      newfile.write(''.join(save_lines))

    finally:

      newfile.close()

    logger.Debug("Wrote new known_hosts.")

    os.rename(tmpname, constants.SSH_KNOWN_HOSTS_FILE)

  elif add_lines:

    # Simply appending a new line will do the trick.

    f.seek(0, 2)

    for add in add_lines:

      f.write(add)

  f.close()

    _UpdateKnownHosts(hostname.name, hostname.ip, sshkey)

    _UpdateKnownHosts(new_node.name, new_node.primary_ip,

                      self.cfg.GetHostKey())