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core-admin/qubes/app.py
Rusty Bird 8d1913a8cc
app: create /var/lib/qubes as file-reflink if supported 
Use the file-reflink storage driver if /var/lib/qubes is on a filesystem
that supports reflinks, e.g. when the btrfs layout was selected in
Anaconda. If it doesn't support reflinks (or if detection fails, e.g. in
an unprivileged test environment), use 'file' as before.
2018-09-11 23:50:26 +00:00

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#
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2010-2015 Joanna Rutkowska <joanna@invisiblethingslab.com>
# Copyright (C) 2011-2015 Marek Marczykowski-Górecki
# <marmarek@invisiblethingslab.com>
# Copyright (C) 2014-2015 Wojtek Porczyk <woju@invisiblethingslab.com>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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 this library; if not, see <https://www.gnu.org/licenses/>.
#
import collections
import copy
import errno
import functools
import grp
import itertools
import logging
import os
import random
import sys
import tempfile
import time
import traceback
import uuid
import jinja2
import libvirt
import lxml.etree
try:
import xen.lowlevel.xs # pylint: disable=wrong-import-order
import xen.lowlevel.xc # pylint: disable=wrong-import-order
except ImportError:
pass
if os.name == 'posix':
# pylint: disable=wrong-import-order
import fcntl
elif os.name == 'nt':
# pylint: disable=import-error
import win32con
import win32file
import pywintypes
else:
raise RuntimeError("Qubes works only on POSIX or WinNT systems")
# pylint: disable=wrong-import-position
import qubes
import qubes.ext
import qubes.utils
import qubes.storage
import qubes.storage.reflink
import qubes.vm
import qubes.vm.adminvm
import qubes.vm.qubesvm
import qubes.vm.templatevm
# pylint: enable=wrong-import-position
class VirDomainWrapper:
# pylint: disable=too-few-public-methods
def __init__(self, connection, vm):
self._connection = connection
self._vm = vm
def _reconnect_if_dead(self):
is_dead = not self._vm.connect().isAlive()
if is_dead:
# pylint: disable=protected-access
self._connection._reconnect_if_dead()
self._vm = self._connection._conn.lookupByUUID(self._vm.UUID())
return is_dead
def __getattr__(self, attrname):
attr = getattr(self._vm, attrname)
if not isinstance(attr, collections.Callable):
return attr
@functools.wraps(attr)
def wrapper(*args, **kwargs):
try:
return attr(*args, **kwargs)
except libvirt.libvirtError:
if self._reconnect_if_dead():
return getattr(self._vm, attrname)(*args, **kwargs)
raise
return wrapper
class VirConnectWrapper:
# pylint: disable=too-few-public-methods
def __init__(self, uri):
self._conn = libvirt.open(uri)
def _reconnect_if_dead(self):
is_dead = not self._conn.isAlive()
if is_dead:
self._conn = libvirt.open(self._conn.getURI())
# TODO: re-register event handlers
return is_dead
def _wrap_domain(self, ret):
if isinstance(ret, libvirt.virDomain):
ret = VirDomainWrapper(self, ret)
return ret
def __getattr__(self, attrname):
attr = getattr(self._conn, attrname)
if not isinstance(attr, collections.Callable):
return attr
if attrname == 'close':
return attr
@functools.wraps(attr)
def wrapper(*args, **kwargs):
try:
return self._wrap_domain(attr(*args, **kwargs))
except libvirt.libvirtError:
if self._reconnect_if_dead():
return self._wrap_domain(
getattr(self._conn, attrname)(*args, **kwargs))
raise
return wrapper
class VMMConnection:
'''Connection to Virtual Machine Manager (libvirt)'''
def __init__(self, offline_mode=None):
'''
:param offline_mode: enable/disable offline mode; default is to
enable when running in chroot as root, otherwise disable
'''
if offline_mode is None:
offline_mode = bool(os.getuid() == 0 and
os.stat('/') != os.stat('/proc/1/root/.'))
self._offline_mode = offline_mode
self._libvirt_conn = None
self._xs = None
self._xc = None
@property
def offline_mode(self):
'''Check or enable offline mode (do not actually connect to vmm)'''
return self._offline_mode
def _libvirt_error_handler(self, ctx, error):
pass
def init_vmm_connection(self):
'''Initialise connection
This method is automatically called when getting'''
if self._libvirt_conn is not None:
# Already initialized
return
if self._offline_mode:
# Do not initialize in offline mode
raise qubes.exc.QubesException(
'VMM operations disabled in offline mode')
if 'xen.lowlevel.xs' in sys.modules:
self._xs = xen.lowlevel.xs.xs()
if 'xen.lowlevel.xc' in sys.modules:
self._xc = xen.lowlevel.xc.xc()
self._libvirt_conn = VirConnectWrapper(
qubes.config.defaults['libvirt_uri'])
libvirt.registerErrorHandler(self._libvirt_error_handler, None)
@property
def libvirt_conn(self):
'''Connection to libvirt'''
self.init_vmm_connection()
return self._libvirt_conn
@property
def xs(self):
'''Connection to Xen Store
This property in available only when running on Xen.
'''
# XXX what about the case when we run under KVM,
# but xen modules are importable?
if 'xen.lowlevel.xs' not in sys.modules:
raise AttributeError(
'xs object is available under Xen hypervisor only')
self.init_vmm_connection()
return self._xs
@property
def xc(self):
'''Connection to Xen
This property in available only when running on Xen.
'''
# XXX what about the case when we run under KVM,
# but xen modules are importable?
if 'xen.lowlevel.xc' not in sys.modules:
raise AttributeError(
'xc object is available under Xen hypervisor only')
self.init_vmm_connection()
return self._xc
def close(self):
libvirt.registerErrorHandler(None, None)
if self._xs:
self._xs.close()
self._xs = None
if self._libvirt_conn:
self._libvirt_conn.close()
self._libvirt_conn = None
self._xc = None # and pray it will get garbage-collected
class QubesHost:
'''Basic information about host machine
:param qubes.Qubes app: Qubes application context (must have \
:py:attr:`Qubes.vmm` attribute defined)
'''
def __init__(self, app):
self.app = app
self._no_cpus = None
self._total_mem = None
self._physinfo = None
def _fetch(self):
if self._no_cpus is not None:
return
# pylint: disable=unused-variable
(model, memory, cpus, mhz, nodes, socket, cores, threads) = \
self.app.vmm.libvirt_conn.getInfo()
self._total_mem = int(memory) * 1024
self._no_cpus = cpus
self.app.log.debug('QubesHost: no_cpus={} memory_total={}'.format(
self.no_cpus, self.memory_total))
try:
self.app.log.debug('QubesHost: xen_free_memory={}'.format(
self.get_free_xen_memory()))
except NotImplementedError:
pass
@property
def memory_total(self):
'''Total memory, in kbytes'''
if self.app.vmm.offline_mode:
return 2**64-1
self._fetch()
return self._total_mem
@property
def no_cpus(self):
'''Number of CPUs'''
if self.app.vmm.offline_mode:
return 42
self._fetch()
return self._no_cpus
def get_free_xen_memory(self):
'''Get free memory from Xen's physinfo.
:raises NotImplementedError: when not under Xen
'''
try:
self._physinfo = self.app.xc.physinfo()
except AttributeError:
raise NotImplementedError('This function requires Xen hypervisor')
return int(self._physinfo['free_memory'])
def get_vm_stats(self, previous_time=None, previous=None, only_vm=None):
'''Measure cpu usage for all domains at once.
If previous measurements are given, CPU usage will be given in
percents of time. Otherwise only absolute value (seconds).
Return a tuple of (measurements_time, measurements),
where measurements is a dictionary with key: domid, value: dict:
- cpu_time - absolute CPU usage (seconds since its startup)
- cpu_usage - CPU usage in %
- memory_kb - current memory assigned, in kb
This function requires Xen hypervisor.
..warning:
This function may return info about implementation-specific VMs,
like stubdomains for HVM
:param previous: previous measurement
:param previous_time: time of previous measurement
:param only_vm: get measurements only for this VM
:raises NotImplementedError: when not under Xen
'''
if (previous_time is None) != (previous is None):
raise ValueError(
'previous and previous_time must be given together (or none)')
if previous is None:
previous = {}
current_time = time.time()
current = {}
try:
if only_vm:
xid = only_vm.xid
if xid < 0:
raise qubes.exc.QubesVMNotRunningError(only_vm)
info = self.app.vmm.xc.domain_getinfo(xid, 1)
if info[0]['domid'] != xid:
raise qubes.exc.QubesVMNotRunningError(only_vm)
else:
info = self.app.vmm.xc.domain_getinfo(0, 1024)
except AttributeError:
raise NotImplementedError(
'This function requires Xen hypervisor')
# TODO: add stubdomain stats to actual VMs
for vm in info:
domid = vm['domid']
current[domid] = {}
current[domid]['memory_kb'] = vm['mem_kb']
current[domid]['cpu_time'] = int(
vm['cpu_time'] / max(vm['online_vcpus'], 1))
if domid in previous:
current[domid]['cpu_usage'] = int(
(current[domid]['cpu_time'] - previous[domid]['cpu_time'])
/ 1000 ** 3 * 100 / (current_time - previous_time))
if current[domid]['cpu_usage'] < 0:
# VM has been rebooted
current[domid]['cpu_usage'] = 0
else:
current[domid]['cpu_usage'] = 0
return (current_time, current)
class VMCollection:
'''A collection of Qubes VMs
VMCollection supports ``in`` operator. You may test for ``qid``, ``name``
and whole VM object's presence.
Iterating over VMCollection will yield machine objects.
'''
def __init__(self, app):
self.app = app
self._dict = dict()
def close(self):
del self.app
self._dict.clear()
del self._dict
def __repr__(self):
return '<{} {!r}>'.format(
self.__class__.__name__, list(sorted(self.keys())))
def items(self):
'''Iterate over ``(qid, vm)`` pairs'''
for qid in self.qids():
yield (qid, self[qid])
def qids(self):
'''Iterate over all qids
qids are sorted by numerical order.
'''
return iter(sorted(self._dict.keys()))
keys = qids
def names(self):
'''Iterate over all names
names are sorted by lexical order.
'''
return iter(sorted(vm.name for vm in self._dict.values()))
def vms(self):
'''Iterate over all machines
vms are sorted by qid.
'''
return iter(sorted(self._dict.values()))
__iter__ = vms
values = vms
def add(self, value, _enable_events=True):
'''Add VM to collection
:param qubes.vm.BaseVM value: VM to add
:raises TypeError: when value is of wrong type
:raises ValueError: when there is already VM which has equal ``qid``
'''
# this violates duck typing, but is needed
# for VMProperty to function correctly
if not isinstance(value, qubes.vm.BaseVM):
raise TypeError('{} holds only BaseVM instances'.format(
self.__class__.__name__))
if value.qid in self:
raise ValueError('This collection already holds VM that has '
'qid={!r} ({!r})'.format(value.qid, self[value.qid]))
if value.name in self:
raise ValueError('A VM named {!s} already exists'
.format(value.name))
self._dict[value.qid] = value
if _enable_events:
value.events_enabled = True
self.app.fire_event('domain-add', vm=value)
return value
def __getitem__(self, key):
if isinstance(key, int):
return self._dict[key]
if isinstance(key, str):
for vm in self:
if vm.name == key:
return vm
raise KeyError(key)
if isinstance(key, qubes.vm.BaseVM):
key = key.uuid
if isinstance(key, uuid.UUID):
for vm in self:
if vm.uuid == key:
return vm
raise KeyError(key)
raise KeyError(key)
def __delitem__(self, key):
vm = self[key]
if not vm.is_halted():
raise qubes.exc.QubesVMNotHaltedError(vm)
self.app.fire_event('domain-pre-delete', pre_event=True, vm=vm)
try:
if vm.libvirt_domain:
vm.libvirt_domain.undefine()
# pylint: disable=protected-access
vm._libvirt_domain = None
except libvirt.libvirtError as e:
if e.get_error_code() == libvirt.VIR_ERR_NO_DOMAIN:
# already undefined
pass
del self._dict[vm.qid]
self.app.fire_event('domain-delete', vm=vm)
def __contains__(self, key):
return any((key in (vm, vm.qid, vm.name))
for vm in self)
def __len__(self):
return len(self._dict)
def get_vms_based_on(self, template):
template = self[template]
return set(vm for vm in self
if hasattr(vm, 'template') and vm.template == template)
def get_vms_connected_to(self, netvm):
new_vms = set([self[netvm]])
dependent_vms = set()
# Dependency resolving only makes sense on NetVM (or derivative)
# if not self[netvm_qid].is_netvm():
# return set([])
while new_vms:
cur_vm = new_vms.pop()
for vm in cur_vm.connected_vms:
if vm in dependent_vms:
continue
dependent_vms.add(vm)
# if vm.is_netvm():
new_vms.add(vm)
return dependent_vms
# XXX with Qubes Admin Api this will probably lead to race condition
# whole process of creating and adding should be synchronised
def get_new_unused_qid(self):
used_ids = set(self.qids())
for i in range(1, qubes.config.max_qid):
if i not in used_ids:
return i
raise LookupError("Cannot find unused qid!")
def get_new_unused_dispid(self):
for _ in range(int(qubes.config.max_dispid ** 0.5)):
dispid = random.SystemRandom().randrange(qubes.config.max_dispid)
if not any(getattr(vm, 'dispid', None) == dispid for vm in self):
return dispid
raise LookupError((
'https://xkcd.com/221/',
'http://dilbert.com/strip/2001-10-25')[random.randint(0, 1)])
def _default_pool(app):
''' Default storage pool.
1. If there is one named 'default', use it.
2. Check if root fs is on LVM thin - use that
3. Look for file(-reflink)-based pool pointing to /var/lib/qubes
4. Fail
'''
if 'default' in app.pools:
return app.pools['default']
if 'DEFAULT_LVM_POOL' in os.environ:
thin_pool = os.environ['DEFAULT_LVM_POOL']
for pool in app.pools.values():
if pool.config.get('driver', None) != 'lvm_thin':
continue
if pool.config['thin_pool'] == thin_pool:
return pool
# no DEFAULT_LVM_POOL, or pool not defined
root_volume_group, root_thin_pool = \
qubes.storage.DirectoryThinPool.thin_pool('/')
if root_thin_pool:
for pool in app.pools.values():
if pool.config.get('driver', None) != 'lvm_thin':
continue
if (pool.config['volume_group'] == root_volume_group and
pool.config['thin_pool'] == root_thin_pool):
return pool
# not a thin volume? look for file pools
for pool in app.pools.values():
if pool.config.get('driver', None) not in ('file', 'file-reflink'):
continue
if pool.config['dir_path'] == qubes.config.qubes_base_dir:
return pool
raise AttributeError('Cannot determine default storage pool')
def _setter_pool(app, prop, value):
if isinstance(value, qubes.storage.Pool):
return value
try:
return app.pools[value]
except KeyError:
raise qubes.exc.QubesPropertyValueError(app, prop, value,
'No such storage pool')
def _setter_default_netvm(app, prop, value):
# skip netvm loop check while loading qubes.xml, to avoid tricky loading
# order
if not app.events_enabled:
return value
if value is None:
return value
# forbid setting to a value that would result in netvm loop
for vm in app.domains:
if not hasattr(vm, 'netvm'):
continue
if not vm.property_is_default('netvm'):
continue
if value == vm \
or value in app.domains.get_vms_connected_to(vm):
raise qubes.exc.QubesPropertyValueError(app, prop, value,
'Network loop on \'{!s}\''.format(vm))
return value
class Qubes(qubes.PropertyHolder):
'''Main Qubes application
:param str store: path to ``qubes.xml``
The store is loaded in stages:
1. In the first stage there are loaded some basic features from store
(currently labels).
2. In the second stage stubs for all VMs are loaded. They are filled
with their basic properties, like ``qid`` and ``name``.
3. In the third stage all global properties are loaded. They often
reference VMs, like default netvm, so they should be filled after
loading VMs.
4. In the fourth stage all remaining VM properties are loaded. They
also need all VMs loaded, because they represent dependencies
between VMs like aforementioned netvm.
5. In the fifth stage there are some fixups to ensure sane system
operation.
This class emits following events:
.. event:: domain-add (subject, event, vm)
When domain is added.
:param subject: Event emitter
:param event: Event name (``'domain-add'``)
:param vm: Domain object
.. event:: domain-pre-delete (subject, event, vm)
When domain is deleted. VM still has reference to ``app`` object,
and is contained within VMCollection. You may prevent removal by
raising an exception.
:param subject: Event emitter
:param event: Event name (``'domain-pre-delete'``)
:param vm: Domain object
.. event:: domain-delete (subject, event, vm)
When domain is deleted. VM still has reference to ``app`` object,
but is not contained within VMCollection.
:param subject: Event emitter
:param event: Event name (``'domain-delete'``)
:param vm: Domain object
Methods and attributes:
'''
default_netvm = qubes.VMProperty('default_netvm', load_stage=3,
default=None, allow_none=True,
setter=_setter_default_netvm,
doc='''Default NetVM for AppVMs. Initial state is `None`, which means
that AppVMs are not connected to the Internet.''')
default_template = qubes.VMProperty('default_template', load_stage=3,
vmclass=qubes.vm.templatevm.TemplateVM,
doc='Default template for new AppVMs')
updatevm = qubes.VMProperty('updatevm', load_stage=3,
default=None, allow_none=True,
doc='''Which VM to use as `yum` proxy for updating AdminVM and
TemplateVMs''')
clockvm = qubes.VMProperty('clockvm', load_stage=3,
default=None, allow_none=True,
doc='Which VM to use as NTP proxy for updating AdminVM')
default_kernel = qubes.property('default_kernel', load_stage=3,
doc='Which kernel to use when not overriden in VM')
default_dispvm = qubes.VMProperty('default_dispvm', load_stage=3,
default=None,
doc='Default DispVM base for service calls', allow_none=True)
default_pool = qubes.property('default_pool', load_stage=3,
default=_default_pool,
setter=_setter_pool,
doc='Default storage pool')
default_pool_private = qubes.property('default_pool_private', load_stage=3,
default=lambda app: app.default_pool,
setter=_setter_pool,
doc='Default storage pool for private volumes')
default_pool_root = qubes.property('default_pool_root', load_stage=3,
default=lambda app: app.default_pool,
setter=_setter_pool,
doc='Default storage pool for root volumes')
default_pool_volatile = qubes.property('default_pool_volatile',
load_stage=3,
default=lambda app: app.default_pool,
setter=_setter_pool,
doc='Default storage pool for volatile volumes')
default_pool_kernel = qubes.property('default_pool_kernel', load_stage=3,
default=lambda app: app.default_pool,
setter=_setter_pool,
doc='Default storage pool for kernel volumes')
stats_interval = qubes.property('stats_interval',
default=3,
type=int,
doc='Interval in seconds for VM stats reporting (memory, CPU usage)')
# TODO #1637 #892
check_updates_vm = qubes.property('check_updates_vm',
type=bool, setter=qubes.property.bool,
default=True,
doc='check for updates inside qubes')
def __init__(self, store=None, load=True, offline_mode=None, lock=False,
**kwargs):
#: logger instance for logging global messages
self.log = logging.getLogger('app')
self.log.debug('init() -> %#x', id(self))
self.log.debug('stack:')
for frame in traceback.extract_stack():
self.log.debug('%s', frame)
self._extensions = qubes.ext.get_extensions()
#: collection of all VMs managed by this Qubes instance
self.domains = VMCollection(self)
#: collection of all available labels for VMs
self.labels = {}
#: collection of all pools
self.pools = {}
#: Connection to VMM
self.vmm = VMMConnection(offline_mode=offline_mode)
#: Information about host system
self.host = QubesHost(self)
if store is not None:
self._store = store
else:
self._store = os.environ.get('QUBES_XML_PATH',
os.path.join(
qubes.config.qubes_base_dir,
qubes.config.system_path['qubes_store_filename']))
super(Qubes, self).__init__(xml=None, **kwargs)
self.__load_timestamp = None
self.__locked_fh = None
self._domain_event_callback_id = None
#: jinja2 environment for libvirt XML templates
self.env = jinja2.Environment(
loader=jinja2.FileSystemLoader([
'/etc/qubes/templates',
'/usr/share/qubes/templates',
]),
undefined=jinja2.StrictUndefined)
if load:
self.load(lock=lock)
self.events_enabled = True
@property
def store(self):
return self._store
def _migrate_global_properties(self):
'''Migrate renamed/dropped properties'''
if self.xml is None:
return
# drop default_fw_netvm
node_default_fw_netvm = self.xml.find(
'./properties/property[@name=\'default_fw_netvm\']')
if node_default_fw_netvm is not None:
node_default_netvm = self.xml.find(
'./properties/property[@name=\'default_netvm\']')
try:
default_fw_netvm = self.domains[node_default_fw_netvm.text]
if node_default_netvm is None:
default_netvm = None
else:
default_netvm = self.domains[node_default_netvm.text]
if default_netvm != default_fw_netvm:
for vm in self.domains:
if not hasattr(vm, 'netvm'):
continue
if not getattr(vm, 'provides_network', False):
continue
node_netvm = vm.xml.find(
'./properties/property[@name=\'netvm\']')
if node_netvm is not None:
# non-default netvm
continue
# this will unfortunately break "being default"
# property state, but the alternative (changing
# value behind user's back) is worse
properties = vm.xml.find('./properties')
element = lxml.etree.Element('property',
name='netvm')
element.text = default_fw_netvm.name
# manipulate xml directly, before loading netvm
# property, to avoid hitting netvm loop detection
properties.append(element)
except KeyError:
# if default_fw_netvm was set to invalid value, simply
# drop it
pass
node_default_fw_netvm.getparent().remove(node_default_fw_netvm)
def load(self, lock=False):
'''Open qubes.xml
:throws EnvironmentError: failure on parsing store
:throws xml.parsers.expat.ExpatError: failure on parsing store
:raises lxml.etree.XMLSyntaxError: on syntax error in qubes.xml
'''
fh = self._acquire_lock()
self.xml = lxml.etree.parse(fh)
# stage 1: load labels and pools
for node in self.xml.xpath('./labels/label'):
label = qubes.Label.fromxml(node)
self.labels[label.index] = label
for node in self.xml.xpath('./pools/pool'):
name = node.get('name')
assert name, "Pool name '%s' is invalid " % name
try:
self.pools[name] = self._get_pool(**node.attrib)
except qubes.exc.QubesException as e:
self.log.error(str(e))
# stage 2: load VMs
for node in self.xml.xpath('./domains/domain'):
# pylint: disable=no-member
cls = self.get_vm_class(node.get('class'))
vm = cls(self, node)
vm.load_properties(load_stage=2)
vm.init_log()
self.domains.add(vm, _enable_events=False)
if 0 not in self.domains:
self.domains.add(
qubes.vm.adminvm.AdminVM(self, None),
_enable_events=False)
self._migrate_global_properties()
# stage 3: load global properties
self.load_properties(load_stage=3)
# stage 4: fill all remaining VM properties
for vm in self.domains:
vm.load_properties(load_stage=4)
vm.load_extras()
# stage 5: misc fixups
self.property_require('default_netvm', allow_none=True)
self.property_require('default_template')
self.property_require('clockvm', allow_none=True)
self.property_require('updatevm', allow_none=True)
for vm in self.domains:
vm.events_enabled = True
vm.fire_event('domain-load')
# get a file timestamp (before closing it - still holding the lock!),
# to detect whether anyone else have modified it in the meantime
self.__load_timestamp = os.path.getmtime(self._store)
if not lock:
self._release_lock()
def __xml__(self):
element = lxml.etree.Element('qubes')
element.append(self.xml_labels())
pools_xml = lxml.etree.Element('pools')
for pool in self.pools.values():
xml = pool.__xml__()
if xml is not None:
pools_xml.append(xml)
element.append(pools_xml)
element.append(self.xml_properties())
domains = lxml.etree.Element('domains')
for vm in self.domains:
domains.append(vm.__xml__())
element.append(domains)
return element
def __str__(self):
return type(self).__name__
def save(self, lock=True):
'''Save all data to qubes.xml
There are several problems with saving :file:`qubes.xml` which must be
mitigated:
- Running out of disk space. No space left should not result in empty
file. This is done by writing to temporary file and then renaming.
- Attempts to write two or more files concurrently. This is done by
sophisticated locking.
:param bool lock: keep file locked after saving
:throws EnvironmentError: failure on saving
'''
if not self.__locked_fh:
self._acquire_lock(for_save=True)
fh_new = tempfile.NamedTemporaryFile(
prefix=self._store, delete=False)
lxml.etree.ElementTree(self.__xml__()).write(
fh_new, encoding='utf-8', pretty_print=True)
fh_new.flush()
try:
os.chown(fh_new.name, -1, grp.getgrnam('qubes').gr_gid)
os.chmod(fh_new.name, 0o660)
except KeyError: # group 'qubes' not found
# don't change mode if no 'qubes' group in the system
pass
os.rename(fh_new.name, self._store)
# update stored mtime, in case of multiple save() calls without
# loading qubes.xml again
self.__load_timestamp = os.path.getmtime(self._store)
# this releases lock for all other processes,
# but they should instantly block on the new descriptor
self.__locked_fh.close()
self.__locked_fh = fh_new
if not lock:
self._release_lock()
def close(self):
'''Deconstruct the object and break circular references
After calling this the object is unusable, not even for saving.'''
self.log.debug('close() <- %#x', id(self))
for frame in traceback.extract_stack():
self.log.debug('%s', frame)
super().close()
if self._domain_event_callback_id is not None:
self.vmm.libvirt_conn.domainEventDeregisterAny(
self._domain_event_callback_id)
self._domain_event_callback_id = None
# Only our Lord, The God Almighty, knows what references
# are kept in extensions.
del self._extensions
for vm in self.domains:
vm.close()
self.domains.close()
del self.domains
self.vmm.close()
del self.vmm
del self.host
if self.__locked_fh:
self._release_lock()
def _acquire_lock(self, for_save=False):
assert self.__locked_fh is None, 'double lock'
while True:
try:
fd = os.open(self._store,
os.O_RDWR | (os.O_CREAT * int(for_save)))
except OSError as e:
if not for_save and e.errno == errno.ENOENT:
raise qubes.exc.QubesException(
'Qubes XML store {!r} is missing; '
'use qubes-create tool'.format(self._store))
raise
# While we were waiting for lock, someone could have unlink()ed
# (or rename()d) our file out of the filesystem. We have to
# ensure we got lock on something linked to filesystem.
# If not, try again.
if os.fstat(fd) != os.stat(self._store):
os.close(fd)
continue
if self.__load_timestamp and \
os.path.getmtime(self._store) != self.__load_timestamp:
os.close(fd)
raise qubes.exc.QubesException(
'Someone else modified qubes.xml in the meantime')
break
if os.name == 'posix':
fcntl.lockf(fd, fcntl.LOCK_EX)
elif os.name == 'nt':
# pylint: disable=protected-access
overlapped = pywintypes.OVERLAPPED()
win32file.LockFileEx(
win32file._get_osfhandle(fd),
win32con.LOCKFILE_EXCLUSIVE_LOCK, 0, -0x10000, overlapped)
self.__locked_fh = os.fdopen(fd, 'r+b')
return self.__locked_fh
def _release_lock(self):
assert self.__locked_fh is not None, 'double release'
# intentionally do not call explicit unlock to not unlock the file
# before all buffers are flushed
self.__locked_fh.close()
self.__locked_fh = None
def load_initial_values(self):
self.labels = {
1: qubes.Label(1, '0xcc0000', 'red'),
2: qubes.Label(2, '0xf57900', 'orange'),
3: qubes.Label(3, '0xedd400', 'yellow'),
4: qubes.Label(4, '0x73d216', 'green'),
5: qubes.Label(5, '0x555753', 'gray'),
6: qubes.Label(6, '0x3465a4', 'blue'),
7: qubes.Label(7, '0x75507b', 'purple'),
8: qubes.Label(8, '0x000000', 'black'),
}
assert max(self.labels.keys()) == qubes.config.max_default_label
pool_configs = copy.deepcopy(qubes.config.defaults['pool_configs'])
root_volume_group, root_thin_pool = \
qubes.storage.DirectoryThinPool.thin_pool('/')
if root_thin_pool:
lvm_config = {
'name': 'lvm',
'driver': 'lvm_thin',
'volume_group': root_volume_group,
'thin_pool': root_thin_pool
}
pool_configs[lvm_config['name']] = lvm_config
for name, config in pool_configs.items():
if 'driver' not in config and 'dir_path' in config:
config['driver'] = 'file'
try:
os.makedirs(config['dir_path'], exist_ok=True)
if qubes.storage.reflink.is_supported(config['dir_path']):
config['driver'] = 'file-reflink'
config['setup_check'] = 'no' # don't check twice
except PermissionError: # looks like a testing environment
pass # stay with 'file'
self.pools[name] = self._get_pool(**config)
self.default_pool_kernel = 'linux-kernel'
self.domains.add(
qubes.vm.adminvm.AdminVM(self, None, label='black'))
@classmethod
def create_empty_store(cls, *args, **kwargs):
self = cls(*args, load=False, **kwargs)
if os.path.exists(self.store):
raise qubes.exc.QubesException(
'{} already exists, aborting'.format(self.store))
self.load_initial_values()
# TODO py3 get lock= as keyword-only arg
self.save(kwargs.get('lock'))
return self
def xml_labels(self):
'''Serialise labels
:rtype: lxml.etree._Element
'''
labels = lxml.etree.Element('labels')
for label in sorted(self.labels.values(), key=lambda labl: labl.index):
labels.append(label.__xml__())
return labels
@staticmethod
def get_vm_class(clsname):
'''Find the class for a domain.
Classes are registered as setuptools' entry points in ``qubes.vm``
group. Any package may supply their own classes.
:param str clsname: name of the class
:return type: class
'''
try:
return qubes.utils.get_entry_point_one(
qubes.vm.VM_ENTRY_POINT, clsname)
except KeyError:
raise qubes.exc.QubesException(
'no such VM class: {!r}'.format(clsname))
# don't catch TypeError
def add_new_vm(self, cls, qid=None, **kwargs):
'''Add new Virtual Machine to collection
'''
if qid is None:
qid = self.domains.get_new_unused_qid()
if isinstance(cls, str):
cls = self.get_vm_class(cls)
# handle default template; specifically allow template=None (do not
# override it with default template)
if 'template' not in kwargs and hasattr(cls, 'template'):
if cls == self.get_vm_class('DispVM'):
kwargs['template'] = self.default_dispvm
else:
kwargs['template'] = self.default_template
elif 'template' in kwargs and isinstance(kwargs['template'], str):
kwargs['template'] = self.domains[kwargs['template']]
return self.domains.add(cls(self, None, qid=qid, **kwargs))
def get_label(self, label):
'''Get label as identified by index or name
:throws KeyError: when label is not found
'''
# first search for index, verbatim
try:
return self.labels[label]
except KeyError:
pass
# then search for name
for i in self.labels.values():
if i.name == label:
return i
# last call, if label is a number represented as str, search in indices
try:
return self.labels[int(label)]
except (KeyError, ValueError):
pass
raise KeyError(label)
def setup_pools(self):
""" Run implementation specific setup for each storage pool. """
for pool in self.pools.values():
pool.setup()
def add_pool(self, name, **kwargs):
""" Add a storage pool to config."""
if name in self.pools.keys():
raise qubes.exc.QubesException('pool named %s already exists \n' %
name)
kwargs['name'] = name
pool = self._get_pool(**kwargs)
pool.setup()
self.pools[name] = pool
return pool
def remove_pool(self, name):
""" Remove a storage pool from config file. """
try:
pool = self.pools[name]
del self.pools[name]
pool.destroy()
except KeyError:
return
def get_pool(self, pool):
''' Returns a :py:class:`qubes.storage.Pool` instance '''
if isinstance(pool, qubes.storage.Pool):
return pool
try:
return self.pools[pool]
except KeyError:
raise qubes.exc.QubesException('Unknown storage pool ' + pool)
@staticmethod
def _get_pool(**kwargs):
try:
name = kwargs['name']
assert name, 'Name needs to be an non empty string'
except KeyError:
raise qubes.exc.QubesException('No pool name for pool')
try:
driver = kwargs['driver']
except KeyError:
raise qubes.exc.QubesException('No driver specified for pool ' +
name)
try:
klass = qubes.utils.get_entry_point_one(
qubes.storage.STORAGE_ENTRY_POINT, driver)
del kwargs['driver']
return klass(**kwargs)
except KeyError:
raise qubes.exc.QubesException('No driver %s for pool %s' %
(driver, name))
def register_event_handlers(self):
'''Register libvirt event handlers, which will translate libvirt
events into qubes.events. This function should be called only in
'qubesd' process and only when mainloop has been already set.
'''
self._domain_event_callback_id = (
self.vmm.libvirt_conn.domainEventRegisterAny(
None, # any domain
libvirt.VIR_DOMAIN_EVENT_ID_LIFECYCLE,
self._domain_event_callback,
None))
def _domain_event_callback(self, _conn, domain, event, _detail, _opaque):
'''Generic libvirt event handler (virConnectDomainEventCallback),
translate libvirt event into qubes.events.
'''
if not self.events_enabled:
return
try:
vm = self.domains[domain.name()]
except KeyError:
# ignore events for unknown domains
return
if event == libvirt.VIR_DOMAIN_EVENT_STOPPED:
vm.on_libvirt_domain_stopped()
elif event == libvirt.VIR_DOMAIN_EVENT_SUSPENDED:
try:
vm.fire_event('domain-paused')
except Exception: # pylint: disable=broad-except
self.log.exception(
'Uncaught exception from domain-paused handler '
'for domain %s', vm.name)
elif event == libvirt.VIR_DOMAIN_EVENT_RESUMED:
try:
vm.fire_event('domain-unpaused')
except Exception: # pylint: disable=broad-except
self.log.exception(
'Uncaught exception from domain-unpaused handler '
'for domain %s', vm.name)
@qubes.events.handler('domain-pre-delete')
def on_domain_pre_deleted(self, event, vm):
# pylint: disable=unused-argument
for obj in itertools.chain(self.domains, (self,)):
for prop in obj.property_list():
try:
if isinstance(prop, qubes.vm.VMProperty) and \
getattr(obj, prop.__name__) == vm:
self.log.error(
'Cannot remove %s, used by %s.%s',
vm, obj, prop.__name__)
raise qubes.exc.QubesVMInUseError(vm,
'Domain is in use: {!r}; details in system log'
.format(vm.name))
except AttributeError:
pass
@qubes.events.handler('domain-delete')
def on_domain_deleted(self, event, vm):
# pylint: disable=unused-argument
for propname in (
'default_netvm',
'default_fw_netvm',
'clockvm',
'updatevm',
'default_template',
):
try:
if getattr(self, propname) == vm:
delattr(self, propname)
except AttributeError:
pass
@qubes.events.handler('property-pre-set:clockvm')
def on_property_pre_set_clockvm(self, event, name, newvalue, oldvalue=None):
# pylint: disable=unused-argument,no-self-use
if newvalue is None:
return
if 'service.clocksync' not in newvalue.features:
newvalue.features['service.clocksync'] = True
@qubes.events.handler('property-set:clockvm')
def on_property_set_clockvm(self, event, name, newvalue, oldvalue=None):
# pylint: disable=unused-argument,no-self-use
if oldvalue and oldvalue.features.get('service.clocksync', False):
del oldvalue.features['service.clocksync']
@qubes.events.handler('property-pre-set:default_netvm')
def on_property_pre_set_default_netvm(self, event, name, newvalue,
oldvalue=None):
# pylint: disable=unused-argument,invalid-name
if newvalue is not None and oldvalue is not None \
and oldvalue.is_running() and not newvalue.is_running() \
and self.domains.get_vms_connected_to(oldvalue):
raise qubes.exc.QubesVMNotRunningError(newvalue,
'Cannot change {!r} to domain that '
'is not running ({!r}).'.format(name, newvalue.name))
@qubes.events.handler('property-set:default_fw_netvm')
def on_property_set_default_fw_netvm(self, event, name, newvalue,
oldvalue=None):
# pylint: disable=unused-argument,invalid-name
for vm in self.domains:
if hasattr(vm, 'provides_network') and vm.provides_network and \
hasattr(vm, 'netvm') and vm.property_is_default('netvm'):
# fire property-del:netvm as it is responsible for resetting
# netvm to it's default value
vm.fire_event('property-pre-del:netvm', pre_event=True,
name='netvm', oldvalue=oldvalue)
vm.fire_event('property-del:netvm',
name='netvm', oldvalue=oldvalue)
@qubes.events.handler('property-set:default_netvm')
def on_property_set_default_netvm(self, event, name, newvalue,
oldvalue=None):
# pylint: disable=unused-argument
for vm in self.domains:
if hasattr(vm, 'provides_network') and not vm.provides_network and \
hasattr(vm, 'netvm') and vm.property_is_default('netvm'):
# fire property-del:netvm as it is responsible for resetting
# netvm to it's default value
vm.fire_event('property-pre-del:netvm', pre_event=True,
name='netvm', oldvalue=oldvalue)
vm.fire_event('property-del:netvm',
name='netvm', oldvalue=oldvalue)
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