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#

#

# Copyright (C) 2010 Google Inc.

#

# 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.

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# 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.

"""Module implementing configuration details at runtime.

"""

import grp

import pwd

import threading

import os

import platform

from ganeti import constants

from ganeti import errors

from ganeti import luxi

from ganeti import pathutils

from ganeti import ssconf

from ganeti import utils

_priv = None

_priv_lock = threading.Lock()

#: Architecture information

_arch = None

def GetUid(user, _getpwnam):

  """Retrieve the uid from the database.

  @type user: string

  @param user: The username to retrieve

  @return: The resolved uid

  """

  try:

    return _getpwnam(user).pw_uid

  except KeyError, err:

    raise errors.ConfigurationError("User '%s' not found (%s)" % (user, err))

def GetGid(group, _getgrnam):

  """Retrieve the gid from the database.

  @type group: string

  @param group: The group name to retrieve

  @return: The resolved gid

  """

  try:

    return _getgrnam(group).gr_gid

  except KeyError, err:

    raise errors.ConfigurationError("Group '%s' not found (%s)" % (group, err))

class GetentResolver:

  """Resolves Ganeti uids and gids by name.

  @ivar masterd_uid: The resolved uid of the masterd user

  @ivar masterd_gid: The resolved gid of the masterd group

  @ivar confd_uid: The resolved uid of the confd user

  @ivar confd_gid: The resolved gid of the confd group

  @ivar luxid_uid: The resolved uid of the luxid user

  @ivar luxid_gid: The resolved gid of the luxid group

  @ivar rapi_uid: The resolved uid of the rapi user

  @ivar rapi_gid: The resolved gid of the rapi group

  @ivar noded_uid: The resolved uid of the noded user

  @ivar daemons_gid: The resolved gid of the daemons group

  @ivar admin_gid: The resolved gid of the admin group

  """

  def __init__(self, _getpwnam=pwd.getpwnam, _getgrnam=grp.getgrnam):

    """Initialize the resolver.

    """

    # Daemon pairs

    self.masterd_uid = GetUid(constants.MASTERD_USER, _getpwnam)

    self.masterd_gid = GetGid(constants.MASTERD_GROUP, _getgrnam)

    self.confd_uid = GetUid(constants.CONFD_USER, _getpwnam)

    self.confd_gid = GetGid(constants.CONFD_GROUP, _getgrnam)

    self.luxid_uid = GetUid(constants.LUXID_USER, _getpwnam)

    self.luxid_gid = GetGid(constants.LUXID_GROUP, _getgrnam)

    self.rapi_uid = GetUid(constants.RAPI_USER, _getpwnam)

    self.rapi_gid = GetGid(constants.RAPI_GROUP, _getgrnam)

    self.noded_uid = GetUid(constants.NODED_USER, _getpwnam)

    self.noded_gid = GetGid(constants.NODED_GROUP, _getgrnam)

    self.mond_uid = GetUid(constants.MOND_USER, _getpwnam)

    self.mond_gid = GetGid(constants.MOND_GROUP, _getgrnam)

    # Misc Ganeti groups

    self.daemons_gid = GetGid(constants.DAEMONS_GROUP, _getgrnam)

    self.admin_gid = GetGid(constants.ADMIN_GROUP, _getgrnam)

    self._uid2user = {

      self.masterd_uid: constants.MASTERD_USER,

      self.confd_uid: constants.CONFD_USER,

      self.luxid_uid: constants.LUXID_USER,

      self.rapi_uid: constants.RAPI_USER,

      self.noded_uid: constants.NODED_USER,

      self.mond_uid: constants.MOND_USER,

      }

    self._gid2group = {

      self.masterd_gid: constants.MASTERD_GROUP,

      self.confd_gid: constants.CONFD_GROUP,

      self.luxid_gid: constants.LUXID_GROUP,

      self.rapi_gid: constants.RAPI_GROUP,

      self.noded_gid: constants.NODED_GROUP,

      self.mond_gid: constants.MOND_GROUP,

      self.daemons_gid: constants.DAEMONS_GROUP,

      self.admin_gid: constants.ADMIN_GROUP,

      }

    self._user2uid = utils.InvertDict(self._uid2user)

    self._group2gid = utils.InvertDict(self._gid2group)

  def LookupUid(self, uid):

    """Looks which Ganeti user belongs to this uid.

    @param uid: The uid to lookup

    @returns The user name associated with that uid

    """

    try:

      return self._uid2user[uid]

    except KeyError:

      raise errors.ConfigurationError("Unknown Ganeti uid '%d'" % uid)

  def LookupGid(self, gid):

    """Looks which Ganeti group belongs to this gid.

    @param gid: The gid to lookup

    @returns The group name associated with that gid

    """

    try:

      return self._gid2group[gid]

    except KeyError:

      raise errors.ConfigurationError("Unknown Ganeti gid '%d'" % gid)

  def LookupUser(self, name):

    """Looks which uid belongs to this name.

    @param name: The name to lookup

    @returns The uid associated with that user name

    """

    try:

      return self._user2uid[name]

    except KeyError:

      raise errors.ConfigurationError("Unknown Ganeti user '%s'" % name)

  def LookupGroup(self, name):

    """Looks which gid belongs to this name.

    @param name: The name to lookup

    @returns The gid associated with that group name

    """

    try:

      return self._group2gid[name]

    except KeyError:

      raise errors.ConfigurationError("Unknown Ganeti group '%s'" % name)

def GetEnts(resolver=GetentResolver):

  """Singleton wrapper around resolver instance.

  As this method is accessed by multiple threads at the same time

  we need to take thread-safety carefully.

  """

  # We need to use the global keyword here

  global _priv # pylint: disable=W0603

  if not _priv:

    _priv_lock.acquire()

    try:

      if not _priv:

        # W0621: Redefine '_priv' from outer scope (used for singleton)

        _priv = resolver() # pylint: disable=W0621

    finally:

      _priv_lock.release()

  return _priv

def InitArchInfo():

  """Initialize architecture information.

  We can assume this information never changes during the lifetime of a

  process, therefore the information can easily be cached.

  @note: This function uses C{platform.architecture} to retrieve the Python

    binary architecture and does so by forking to run C{file} (see Python

    documentation for more information). Therefore it must not be used in a

    multi-threaded environment.

  """

  global _arch # pylint: disable=W0603

  if _arch is not None:

    raise errors.ProgrammerError("Architecture information can only be"

                                 " initialized once")

  _arch = (platform.architecture()[0], platform.machine())

def GetArchInfo():

  """Returns previsouly initialized architecture information.

  """

  if _arch is None:

    raise errors.ProgrammerError("Architecture information hasn't been"

                                 " initialized")

  return _arch

def GetClient(query=False):

  """Connects to the a luxi socket and returns a client.

  @type query: boolean

  @param query: this signifies that the client will only be

      used for queries; if the build-time parameter

      enable-split-queries is enabled, then the client will be

      connected to the query socket instead of the masterd socket

  """

  override_socket = os.getenv(constants.LUXI_OVERRIDE, "")

  if override_socket:

    if override_socket == constants.LUXI_OVERRIDE_MASTER:

      address = pathutils.MASTER_SOCKET

    elif override_socket == constants.LUXI_OVERRIDE_QUERY:

      address = pathutils.QUERY_SOCKET

    else:

      address = override_socket

  elif query:

    address = pathutils.QUERY_SOCKET

  else:

    address = None

  # TODO: Cache object?

  try:

    client = luxi.Client(address=address)

  except luxi.NoMasterError:

    ss = ssconf.SimpleStore()

    # Try to read ssconf file

    try:

      ss.GetMasterNode()

    except errors.ConfigurationError:

      raise errors.OpPrereqError("Cluster not initialized or this machine is"

                                 " not part of a cluster",

                                 errors.ECODE_INVAL)

    master, myself = ssconf.GetMasterAndMyself(ss=ss)

    if master != myself:

      raise errors.OpPrereqError("This is not the master node, please connect"

                                 " to node '%s' and rerun the command" %

                                 master, errors.ECODE_INVAL)

    raise

  return client