# Copyright 2014-2015 Canonical Limited.
#
# This file is part of charm-helpers.
#
# charm-helpers is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License version 3 as
# published by the Free Software Foundation.
#
# charm-helpers 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with charm-helpers. If not, see <http://www.gnu.org/licenses/>.
"""Tools for working with the host system"""
# Copyright 2012 Canonical Ltd.
#
# Authors:
# Nick Moffitt <nick.moffitt@canonical.com>
# Matthew Wedgwood <matthew.wedgwood@canonical.com>
import os
import re
import pwd
import glob
import grp
import random
import string
import subprocess
import hashlib
from contextlib import contextmanager
from collections import OrderedDict
import six
from .hookenv import log
from .fstab import Fstab
def service_start(service_name):
"""Start a system service"""
return service('start', service_name)
def service_stop(service_name):
"""Stop a system service"""
return service('stop', service_name)
def service_restart(service_name):
"""Restart a system service"""
return service('restart', service_name)
def service_reload(service_name, restart_on_failure=False):
"""Reload a system service, optionally falling back to restart if
reload fails"""
service_result = service('reload', service_name)
if not service_result and restart_on_failure:
service_result = service('restart', service_name)
return service_result
def service_pause(service_name, init_dir="/etc/init", initd_dir="/etc/init.d"):
"""Pause a system service.
Stop it, and prevent it from starting again at boot."""
stopped = service_stop(service_name)
upstart_file = os.path.join(init_dir, "{}.conf".format(service_name))
sysv_file = os.path.join(initd_dir, service_name)
if os.path.exists(upstart_file):
override_path = os.path.join(
init_dir, '{}.override'.format(service_name))
with open(override_path, 'w') as fh:
fh.write("manual\n")
elif os.path.exists(sysv_file):
subprocess.check_call(["update-rc.d", service_name, "disable"])
else:
# XXX: Support SystemD too
raise ValueError(
"Unable to detect {0} as either Upstart {1} or SysV {2}".format(
service_name, upstart_file, sysv_file))
return stopped
def service_resume(service_name, init_dir="/etc/init",
initd_dir="/etc/init.d"):
"""Resume a system service.
Reenable starting again at boot. Start the service"""
upstart_file = os.path.join(init_dir, "{}.conf".format(service_name))
sysv_file = os.path.join(initd_dir, service_name)
if os.path.exists(upstart_file):
override_path = os.path.join(
init_dir, '{}.override'.format(service_name))
if os.path.exists(override_path):
os.unlink(override_path)
elif os.path.exists(sysv_file):
subprocess.check_call(["update-rc.d", service_name, "enable"])
else:
# XXX: Support SystemD too
raise ValueError(
"Unable to detect {0} as either Upstart {1} or SysV {2}".format(
service_name, upstart_file, sysv_file))
started = service_start(service_name)
return started
def service(action, service_name):
"""Control a system service"""
cmd = ['service', service_name, action]
return subprocess.call(cmd) == 0
def service_running(service):
"""Determine whether a system service is running"""
try:
output = subprocess.check_output(
['service', service, 'status'],
stderr=subprocess.STDOUT).decode('UTF-8')
except subprocess.CalledProcessError:
return False
else:
if ("start/running" in output or "is running" in output):
return True
else:
return False
def service_available(service_name):
"""Determine whether a system service is available"""
try:
subprocess.check_output(
['service', service_name, 'status'],
stderr=subprocess.STDOUT).decode('UTF-8')
except subprocess.CalledProcessError as e:
return b'unrecognized service' not in e.output
else:
return True
def adduser(username, password=None, shell='/bin/bash', system_user=False):
"""Add a user to the system"""
try:
user_info = pwd.getpwnam(username)
log('user {0} already exists!'.format(username))
except KeyError:
log('creating user {0}'.format(username))
cmd = ['useradd']
if system_user or password is None:
cmd.append('--system')
else:
cmd.extend([
'--create-home',
'--shell', shell,
'--password', password,
])
cmd.append(username)
subprocess.check_call(cmd)
user_info = pwd.getpwnam(username)
return user_info
def user_exists(username):
"""Check if a user exists"""
try:
pwd.getpwnam(username)
user_exists = True
except KeyError:
user_exists = False
return user_exists
def add_group(group_name, system_group=False):
"""Add a group to the system"""
try:
group_info = grp.getgrnam(group_name)
log('group {0} already exists!'.format(group_name))
except KeyError:
log('creating group {0}'.format(group_name))
cmd = ['addgroup']
if system_group:
cmd.append('--system')
else:
cmd.extend([
'--group',
])
cmd.append(group_name)
subprocess.check_call(cmd)
group_info = grp.getgrnam(group_name)
return group_info
def add_user_to_group(username, group):
"""Add a user to a group"""
cmd = ['gpasswd', '-a', username, group]
log("Adding user {} to group {}".format(username, group))
subprocess.check_call(cmd)
def rsync(from_path, to_path, flags='-r', options=None):
"""Replicate the contents of a path"""
options = options or ['--delete', '--executability']
cmd = ['/usr/bin/rsync', flags]
cmd.extend(options)
cmd.append(from_path)
cmd.append(to_path)
log(" ".join(cmd))
return subprocess.check_output(cmd).decode('UTF-8').strip()
def symlink(source, destination):
"""Create a symbolic link"""
log("Symlinking {} as {}".format(source, destination))
cmd = [
'ln',
'-sf',
source,
destination,
]
subprocess.check_call(cmd)
def mkdir(path, owner='root', group='root', perms=0o555, force=False):
"""Create a directory"""
log("Making dir {} {}:{} {:o}".format(path, owner, group,
perms))
uid = pwd.getpwnam(owner).pw_uid
gid = grp.getgrnam(group).gr_gid
realpath = os.path.abspath(path)
path_exists = os.path.exists(realpath)
if path_exists and force:
if not os.path.isdir(realpath):
log("Removing non-directory file {} prior to mkdir()".format(path))
os.unlink(realpath)
os.makedirs(realpath, perms)
elif not path_exists:
os.makedirs(realpath, perms)
os.chown(realpath, uid, gid)
os.chmod(realpath, perms)
def write_file(path, content, owner='root', group='root', perms=0o444):
"""Create or overwrite a file with the contents of a byte string."""
log("Writing file {} {}:{} {:o}".format(path, owner, group, perms))
uid = pwd.getpwnam(owner).pw_uid
gid = grp.getgrnam(group).gr_gid
with open(path, 'wb') as target:
os.fchown(target.fileno(), uid, gid)
os.fchmod(target.fileno(), perms)
target.write(content)
def fstab_remove(mp):
"""Remove the given mountpoint entry from /etc/fstab
"""
return Fstab.remove_by_mountpoint(mp)
def fstab_add(dev, mp, fs, options=None):
"""Adds the given device entry to the /etc/fstab file
"""
return Fstab.add(dev, mp, fs, options=options)
def mount(device, mountpoint, options=None, persist=False, filesystem="ext3"):
"""Mount a filesystem at a particular mountpoint"""
cmd_args = ['mount']
if options is not None:
cmd_args.extend(['-o', options])
cmd_args.extend([device, mountpoint])
try:
subprocess.check_output(cmd_args)
except subprocess.CalledProcessError as e:
log('Error mounting {} at {}\n{}'.format(device, mountpoint, e.output))
return False
if persist:
return fstab_add(device, mountpoint, filesystem, options=options)
return True
def umount(mountpoint, persist=False):
"""Unmount a filesystem"""
cmd_args = ['umount', mountpoint]
try:
subprocess.check_output(cmd_args)
except subprocess.CalledProcessError as e:
log('Error unmounting {}\n{}'.format(mountpoint, e.output))
return False
if persist:
return fstab_remove(mountpoint)
return True
def mounts():
"""Get a list of all mounted volumes as [[mountpoint,device],[...]]"""
with open('/proc/mounts') as f:
# [['/mount/point','/dev/path'],[...]]
system_mounts = [m[1::-1] for m in [l.strip().split()
for l in f.readlines()]]
return system_mounts
def fstab_mount(mountpoint):
"""Mount filesystem using fstab"""
cmd_args = ['mount', mountpoint]
try:
subprocess.check_output(cmd_args)
except subprocess.CalledProcessError as e:
log('Error unmounting {}\n{}'.format(mountpoint, e.output))
return False
return True
def file_hash(path, hash_type='md5'):
"""
Generate a hash checksum of the contents of 'path' or None if not found.
:param str hash_type: Any hash alrgorithm supported by :mod:`hashlib`,
such as md5, sha1, sha256, sha512, etc.
"""
if os.path.exists(path):
h = getattr(hashlib, hash_type)()
with open(path, 'rb') as source:
h.update(source.read())
return h.hexdigest()
else:
return None
def path_hash(path):
"""
Generate a hash checksum of all files matching 'path'. Standard wildcards
like '*' and '?' are supported, see documentation for the 'glob' module for
more information.
:return: dict: A { filename: hash } dictionary for all matched files.
Empty if none found.
"""
return {
filename: file_hash(filename)
for filename in glob.iglob(path)
}
def check_hash(path, checksum, hash_type='md5'):
"""
Validate a file using a cryptographic checksum.
:param str checksum: Value of the checksum used to validate the file.
:param str hash_type: Hash algorithm used to generate `checksum`.
Can be any hash alrgorithm supported by :mod:`hashlib`,
such as md5, sha1, sha256, sha512, etc.
:raises ChecksumError: If the file fails the checksum
"""
actual_checksum = file_hash(path, hash_type)
if checksum != actual_checksum:
raise ChecksumError("'%s' != '%s'" % (checksum, actual_checksum))
class ChecksumError(ValueError):
pass
def restart_on_change(restart_map, stopstart=False):
"""Restart services based on configuration files changing
This function is used a decorator, for example::
@restart_on_change({
'/etc/ceph/ceph.conf': [ 'cinder-api', 'cinder-volume' ]
'/etc/apache/sites-enabled/*': [ 'apache2' ]
})
def config_changed():
pass # your code here
In this example, the cinder-api and cinder-volume services
would be restarted if /etc/ceph/ceph.conf is changed by the
ceph_client_changed function. The apache2 service would be
restarted if any file matching the pattern got changed, created
or removed. Standard wildcards are supported, see documentation
for the 'glob' module for more information.
"""
def wrap(f):
def wrapped_f(*args, **kwargs):
checksums = {path: path_hash(path) for path in restart_map}
f(*args, **kwargs)
restarts = []
for path in restart_map:
if path_hash(path) != checksums[path]:
restarts += restart_map[path]
services_list = list(OrderedDict.fromkeys(restarts))
if not stopstart:
for service_name in services_list:
service('restart', service_name)
else:
for action in ['stop', 'start']:
for service_name in services_list:
service(action, service_name)
return wrapped_f
return wrap
def lsb_release():
"""Return /etc/lsb-release in a dict"""
d = {}
with open('/etc/lsb-release', 'r') as lsb:
for l in lsb:
k, v = l.split('=')
d[k.strip()] = v.strip()
return d
def pwgen(length=None):
"""Generate a random pasword."""
if length is None:
# A random length is ok to use a weak PRNG
length = random.choice(range(35, 45))
alphanumeric_chars = [
l for l in (string.ascii_letters + string.digits)
if l not in 'l0QD1vAEIOUaeiou']
# Use a crypto-friendly PRNG (e.g. /dev/urandom) for making the
# actual password
random_generator = random.SystemRandom()
random_chars = [
random_generator.choice(alphanumeric_chars) for _ in range(length)]
return(''.join(random_chars))
def is_phy_iface(interface):
"""Returns True if interface is not virtual, otherwise False."""
if interface:
sys_net = '/sys/class/net'
if os.path.isdir(sys_net):
for iface in glob.glob(os.path.join(sys_net, '*')):
if '/virtual/' in os.path.realpath(iface):
continue
if interface == os.path.basename(iface):
return True
return False
def get_bond_master(interface):
"""Returns bond master if interface is bond slave otherwise None.
NOTE: the provided interface is expected to be physical
"""
if interface:
iface_path = '/sys/class/net/%s' % (interface)
if os.path.exists(iface_path):
if '/virtual/' in os.path.realpath(iface_path):
return None
master = os.path.join(iface_path, 'master')
if os.path.exists(master):
master = os.path.realpath(master)
# make sure it is a bond master
if os.path.exists(os.path.join(master, 'bonding')):
return os.path.basename(master)
return None
def list_nics(nic_type=None):
'''Return a list of nics of given type(s)'''
if isinstance(nic_type, six.string_types):
int_types = [nic_type]
else:
int_types = nic_type
interfaces = []
if nic_type:
for int_type in int_types:
cmd = ['ip', 'addr', 'show', 'label', int_type + '*']
ip_output = subprocess.check_output(cmd).decode('UTF-8')
ip_output = ip_output.split('\n')
ip_output = (line for line in ip_output if line)
for line in ip_output:
if line.split()[1].startswith(int_type):
matched = re.search('.*: (' + int_type +
r'[0-9]+\.[0-9]+)@.*', line)
if matched:
iface = matched.groups()[0]
else:
iface = line.split()[1].replace(":", "")
if iface not in interfaces:
interfaces.append(iface)
else:
cmd = ['ip', 'a']
ip_output = subprocess.check_output(cmd).decode('UTF-8').split('\n')
ip_output = (line.strip() for line in ip_output if line)
key = re.compile('^[0-9]+:\s+(.+):')
for line in ip_output:
matched = re.search(key, line)
if matched:
iface = matched.group(1)
iface = iface.partition("@")[0]
if iface not in interfaces:
interfaces.append(iface)
return interfaces
def set_nic_mtu(nic, mtu):
'''Set MTU on a network interface'''
cmd = ['ip', 'link', 'set', nic, 'mtu', mtu]
subprocess.check_call(cmd)
def get_nic_mtu(nic):
cmd = ['ip', 'addr', 'show', nic]
ip_output = subprocess.check_output(cmd).decode('UTF-8').split('\n')
mtu = ""
for line in ip_output:
words = line.split()
if 'mtu' in words:
mtu = words[words.index("mtu") + 1]
return mtu
def get_nic_hwaddr(nic):
cmd = ['ip', '-o', '-0', 'addr', 'show', nic]
ip_output = subprocess.check_output(cmd).decode('UTF-8')
hwaddr = ""
words = ip_output.split()
if 'link/ether' in words:
hwaddr = words[words.index('link/ether') + 1]
return hwaddr
def cmp_pkgrevno(package, revno, pkgcache=None):
'''Compare supplied revno with the revno of the installed package
* 1 => Installed revno is greater than supplied arg
* 0 => Installed revno is the same as supplied arg
* -1 => Installed revno is less than supplied arg
This function imports apt_cache function from charmhelpers.fetch if
the pkgcache argument is None. Be sure to add charmhelpers.fetch if
you call this function, or pass an apt_pkg.Cache() instance.
'''
import apt_pkg
if not pkgcache:
from charmhelpers.fetch import apt_cache
pkgcache = apt_cache()
pkg = pkgcache[package]
return apt_pkg.version_compare(pkg.current_ver.ver_str, revno)
@contextmanager
def chdir(d):
cur = os.getcwd()
try:
yield os.chdir(d)
finally:
os.chdir(cur)
def chownr(path, owner, group, follow_links=True, chowntopdir=False):
"""
Recursively change user and group ownership of files and directories
in given path. Doesn't chown path itself by default, only its children.
:param bool follow_links: Also Chown links if True
:param bool chowntopdir: Also chown path itself if True
"""
uid = pwd.getpwnam(owner).pw_uid
gid = grp.getgrnam(group).gr_gid
if follow_links:
chown = os.chown
else:
chown = os.lchown
if chowntopdir:
broken_symlink = os.path.lexists(path) and not os.path.exists(path)
if not broken_symlink:
chown(path, uid, gid)
for root, dirs, files in os.walk(path):
for name in dirs + files:
full = os.path.join(root, name)
broken_symlink = os.path.lexists(full) and not os.path.exists(full)
if not broken_symlink:
chown(full, uid, gid)
def lchownr(path, owner, group):
chownr(path, owner, group, follow_links=False)