#!/usr/bin/python
# coding=utf-8
#
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT
import os
from xml.dom import minidom as xml
from xml.parsers.expat import ExpatError
from lxml import etree
from .ve_lock import CONFIG_DIR, acquire_lock
# Path to ve.cfg
VE_CFG_PATH = os.path.join(CONFIG_DIR, 've.cfg')
VE_CFG_PATH_TMP = VE_CFG_PATH + '.tmp'
# It's effectively a tuple of ve_cfg and it's lve_config
PARSED_XML_CACHE = (None, None,)
class BadVeConfigException(Exception):
def __init__(self, message='Nothing'):
super().__init__(
f"Unable to parse /etc/container/ve.cfg file, message: {message}"
)
def get_xml_config(use_cache=True):
"""
Load xml config from ve.cfg
1. setup lock on file
2. read info
3. remove lock
:type use_cache: bool
:rtype: tuple[xml.Document, xml.Element]
:raises: BadVeConfigException, LockFailedException
"""
global PARSED_XML_CACHE
if PARSED_XML_CACHE != (None, None,) and use_cache:
# Cache will be updated in save_xml()
return PARSED_XML_CACHE
with acquire_lock():
try:
_ve_cfg = xml.parse(VE_CFG_PATH)
_ve_lveconfig = _ve_cfg.getElementsByTagName("lveconfig")[0]
except (OSError, IOError, ExpatError, IndexError) as e:
raise BadVeConfigException('bad ve.cfg file') from e
if use_cache:
PARSED_XML_CACHE = _ve_cfg, _ve_lveconfig
return _ve_cfg, _ve_lveconfig
def get_xml_config_etree():
# type: () -> etree.ElementBase
"""
This method works same as get_xml_config,
but returns etree object
:rtype: etree.ElementTree
:raises: BadVeConfigException, LockFailedException
"""
with acquire_lock():
try:
tree = etree.parse(VE_CFG_PATH)
return tree.getroot()
except etree.ParseError as e:
raise BadVeConfigException(str(e)) from e
def save_xml(xml_document):
# Update cache on save because we sometimes do re-read right after save
global PARSED_XML_CACHE
_ve_lveconfig = xml_document.getElementsByTagName("lveconfig")[0]
PARSED_XML_CACHE = (xml_document, _ve_lveconfig,)
xml_string = xml_document.toprettyxml(encoding='utf-8', indent='', newl='')
xml_string = xml_string.replace(b"\n", b'').replace(b"\t", b'')
new_xml = xml.parseString(xml_string)
buf = new_xml.toprettyxml(encoding='utf-8')
if not buf: # paranoia mode)
raise RuntimeError(f"Rejected attempt to write empty {VE_CFG_PATH}")
with open(VE_CFG_PATH_TMP, 'wb') as f:
f.write(buf)
f.flush()
os.fsync(f.fileno())
os.rename(VE_CFG_PATH_TMP, VE_CFG_PATH)
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