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#!/usr/bin/python
# Copyright 2018 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Distro helpers."""
import os
import subprocess
import time
def CallDhclient(
interfaces, logger, dhclient_script=None):
"""Configure the network interfaces using dhclient.
Args:
interfaces: list of string, the output device names to enable.
logger: logger object, used to write to SysLog and serial port.
dhclient_script: string, the path to a dhclient script used by dhclient.
"""
logger.info('Enabling the Ethernet interfaces %s.', interfaces)
dhclient_command = ['dhclient']
if dhclient_script and os.path.exists(dhclient_script):
dhclient_command += ['-sf', dhclient_script]
try:
subprocess.check_call(dhclient_command + ['-x'] + interfaces)
subprocess.check_call(dhclient_command + interfaces)
except subprocess.CalledProcessError:
logger.warning('Could not enable interfaces %s.', interfaces)
def CallDhclientIpv6(interfaces, logger, dhclient_script=None,
release_lease=False):
"""Configure the network interfaces for IPv6 using dhclient.
Args:
interface: string, the output device names for enabling IPv6.
logger: logger object, used to write to SysLog and serial port.
dhclient_script: string, the path to a dhclient script used by dhclient.
release_lease: Release the IPv6 lease.
"""
logger.info('Calling Dhclient for IPv6 configuration '
'on the Ethernet interfaces %s.', interfaces)
timeout_command = ['timeout', '5']
dhclient_command = ['dhclient']
if release_lease:
try:
subprocess.check_call(
timeout_command + dhclient_command + [
'-6', '-r', '-v'] + interfaces)
except subprocess.CalledProcessError:
logger.warning('Could not release IPv6 lease on interface %s.',
interfaces)
return
# Check for a 'tentative' IPv6 address which would prevent `dhclient -6` from
# succeeding below. This should only take 1 second, but we try for up to 5.
command = ['ip', '-6', '-o', 'a', 's', 'dev', interfaces[0], 'scope',
'link', 'tentative']
for i in range(5):
output = ''
try:
output = subprocess.check_output(command)
except subprocess.CalledProcessError as e:
logger.warning('Could not confirm tentative IPv6 address: %s.', e.output)
if output:
logger.info('Found tentative ipv6 link address %s, sleeping 1 second.',
output.strip())
time.sleep(1)
else:
break
if dhclient_script and os.path.exists(dhclient_script):
dhclient_command += ['-sf', dhclient_script]
try:
subprocess.check_call(
timeout_command + dhclient_command + ['-1', '-6', '-v'] + interfaces)
except subprocess.CalledProcessError:
logger.warning('Could not enable IPv6 on interface %s.', interfaces)
def CallEnableRouteAdvertisements(interfaces, logger):
"""Enable route advertisements.
Args:
interfaces: list of string, the output device names to enable.
logger: logger object, used to write to SysLog and serial port.
"""
for interface in interfaces:
accept_ra = (
'net.ipv6.conf.{interface}.accept_ra_rt_info_max_plen'.format(
interface=interface))
CallSysctl(logger, accept_ra, 128)
def CallHwclock(logger):
"""Sync clock using hwclock.
Args:
logger: logger object, used to write to SysLog and serial port.
"""
command = ['/sbin/hwclock', '--hctosys']
try:
subprocess.check_call(command)
except subprocess.CalledProcessError:
logger.warning('Failed to sync system time with hardware clock.')
else:
logger.info('Synced system time with hardware clock.')
def CallNtpdate(logger):
"""Sync clock using ntpdate.
Args:
logger: logger object, used to write to SysLog and serial port.
"""
ntpd_inactive = subprocess.call(['service', 'ntpd', 'status'])
try:
if not ntpd_inactive:
subprocess.check_call(['service', 'ntpd', 'stop'])
subprocess.check_call(
'ntpdate `awk \'$1=="server" {print $2}\' /etc/ntp.conf`', shell=True)
if not ntpd_inactive:
subprocess.check_call(['service', 'ntpd', 'start'])
except subprocess.CalledProcessError:
logger.warning('Failed to sync system time with ntp server.')
else:
logger.info('Synced system time with ntp server.')
def CallSysctl(logger, name, value):
"""Write a variable using sysctl.
Args:
logger: logger object, used to write to SysLog and serial port.
name: string name of the sysctl variable.
value: value of the sysctl variable.
"""
logger.info('Configuring sysctl %s.', name)
sysctl_command = [
'sysctl', '-w', '{name}={value}'.format(name=name, value=value)]
try:
subprocess.check_call(sysctl_command)
except subprocess.CalledProcessError:
logger.warning('Unable to configure sysctl %s.', name)
def SystemctlRestart(service, logger):
"""Restart a service using systemctl.
Args:
service: the name of the service to restart.
logger: logger object, used to write to SysLog and serial port.
"""
logger.info('Restarting service via "systemctl restart %s".', service)
systemctl_command = ['systemctl', 'restart', service]
try:
subprocess.check_call(systemctl_command)
except subprocess.CalledProcessError:
logger.warning('Failed to restart service %s.', service)
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