#
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2013-2015 Joanna Rutkowska <joanna@invisiblethingslab.com>
# Copyright (C) 2013-2015 Marek Marczykowski-Górecki
# <marmarek@invisiblethingslab.com>
# Copyright (C) 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/>.
#
""" Qubes storage system"""
from __future__ import absolute_import
import inspect
import os
import os.path
import string # pylint: disable=deprecated-module
import subprocess
import time
from datetime import datetime
import asyncio
import lxml.etree
import pkg_resources
import qubes
import qubes.exc
import qubes.utils
STORAGE_ENTRY_POINT = 'qubes.storage'
class StoragePoolException(qubes.exc.QubesException):
''' A general storage exception '''
pass
class BlockDevice(object):
''' Represents a storage block device. '''
# pylint: disable=too-few-public-methods
def __init__(self, path, name, script=None, rw=True, domain=None,
devtype='disk'):
assert name, 'Missing device name'
assert path, 'Missing device path'
self.path = path
self.name = name
self.rw = rw
self.script = script
self.domain = domain
self.devtype = devtype
class Volume(object):
''' Encapsulates all data about a volume for serialization to qubes.xml and
libvirt config.
Keep in mind!
volatile = not snap_on_start and not save_on_stop
snapshot = snap_on_start and not save_on_stop
origin = not snap_on_start and save_on_stop
origin_snapshot = snap_on_start and save_on_stop
'''
devtype = 'disk'
domain = None
path = None
script = None
#: disk space used by this volume, can be smaller than :py:attr:`size`
#: for sparse volumes
usage = 0
def __init__(self, name, pool, vid,
revisions_to_keep=0, rw=False, save_on_stop=False, size=0,
snap_on_start=False, source=None, **kwargs):
''' Initialize a volume.
:param str name: The name of the volume inside owning domain
:param Pool pool: The pool object
:param str vid: Volume identifier needs to be unique in pool
:param int revisions_to_keep: Amount of revisions to keep around
:param bool rw: If true volume will be mounted read-write
:param bool snap_on_start: Create a snapshot from source on
start, instead of using volume own data
:param bool save_on_stop: Write changes to the volume in
vm.stop(), otherwise - discard
:param Volume source: other volume in same pool to make snapshot
from, required if *snap_on_start*=`True`
:param str/int size: Size of the volume
'''
super(Volume, self).__init__(**kwargs)
assert isinstance(pool, Pool)
assert source is None or (isinstance(source, Volume)
and source.pool == pool)
if snap_on_start and source is None:
msg = "snap_on_start specified on {!r} but no volume source set"
msg = msg.format(name)
raise StoragePoolException(msg)
elif not snap_on_start and source is not None:
msg = "source specified on {!r} but no snap_on_start set"
msg = msg.format(name)
raise StoragePoolException(msg)
#: Name of the volume in a domain it's attached to (like `root` or
#: `private`).
self.name = str(name)
#: :py:class:`Pool` instance owning this volume
self.pool = pool
#: How many revisions of the volume to keep. Each revision is created
# at :py:meth:`stop`, if :py:attr:`save_on_stop` is True
self.revisions_to_keep = int(revisions_to_keep)
#: Should this volume be writable by domain.
self.rw = rw
#: Should volume state be saved or discarded at :py:meth:`stop`
self.save_on_stop = save_on_stop
self._size = int(size)
#: Should the volume state be initialized with a snapshot of
#: same-named volume of domain's template.
self.snap_on_start = snap_on_start
#: source volume for :py:attr:`snap_on_start` volumes
self.source = source
#: Volume unique (inside given pool) identifier
self.vid = vid
def __eq__(self, other):
if isinstance(other, Volume):
return other.pool == self.pool and other.vid == self.vid
return NotImplemented
def __hash__(self):
return hash('%s:%s' % (self.pool, self.vid))
def __neq__(self, other):
return not self.__eq__(other)
def __repr__(self):
return '{!r}'.format(str(self.pool) + ':' + self.vid)
def __str__(self):
return str(self.vid)
def __xml__(self):
config = _sanitize_config(self.config)
return lxml.etree.Element('volume', **config)
def create(self):
''' Create the given volume on disk.
This method is called only once in the volume lifetime. Before
calling this method, no data on disk should be touched (in
context of this volume).
This can be implemented as a coroutine.
'''
raise self._not_implemented("create")
def remove(self):
''' Remove volume.
This can be implemented as a coroutine.'''
raise self._not_implemented("remove")
def export(self):
''' Returns a path to read the volume data from.
Reading from this path when domain owning this volume is
running (i.e. when :py:meth:`is_dirty` is True) should return the
data from before domain startup.
Reading from the path returned by this method should return the
volume data. If extracting volume data require something more
than just reading from file (for example connecting to some other
domain, or decompressing the data), the returned path may be a pipe.
'''
raise self._not_implemented("export")
def import_data(self):
''' Returns a path to overwrite volume data.
This method is called after volume was already :py:meth:`create`-ed.
Writing to this path should overwrite volume data. If importing
volume data require something more than just writing to a file (
for example connecting to some other domain, or converting data
on the fly), the returned path may be a pipe.
'''
raise self._not_implemented("import")
def import_data_end(self, success):
''' End the data import operation. This may be used by pool
implementation to commit changes, cleanup temporary files etc.
This method is called regardless the operation was successful or not.
:param success: True if data import was successful, otherwise False
'''
# by default do nothing
pass
def import_volume(self, src_volume):
''' Imports data from a different volume (possibly in a different
pool.
The volume needs to be create()d first.
This can be implemented as a coroutine. '''
# pylint: disable=unused-argument
raise self._not_implemented("import_volume")
def is_dirty(self):
''' Return `True` if volume was not properly shutdown and committed.
This include the situation when domain owning the volume is still
running.
'''
raise self._not_implemented("is_dirty")
def is_outdated(self):
''' Returns `True` if this snapshot of a source volume (for
`snap_on_start`=True) is outdated.
'''
raise self._not_implemented("is_outdated")
def resize(self, size):
''' Expands volume, throws
:py:class:`qubes.storage.StoragePoolException` if
given size is less than current_size
This can be implemented as a coroutine.
:param int size: new size in bytes
'''
# pylint: disable=unused-argument
raise self._not_implemented("resize")
def revert(self, revision=None):
''' Revert volume to previous revision
:param revision: revision to revert volume to, see :py:attr:`revisions`
'''
# pylint: disable=unused-argument
raise self._not_implemented("revert")
def start(self):
''' Do what ever is needed on start.
This include making a snapshot of template's volume if
:py:attr:`snap_on_start` is set.
This can be implemented as a coroutine.'''
raise self._not_implemented("start")
def stop(self):
''' Do what ever is needed on stop.
This include committing data if :py:attr:`save_on_stop` is set.
This can be implemented as a coroutine.'''
def verify(self):
''' Verifies the volume.
This function is supposed to either return :py:obj:`True`, or raise
an exception.
This can be implemented as a coroutine.'''
raise self._not_implemented("verify")
def block_device(self):
''' Return :py:class:`BlockDevice` for serialization in
the libvirt XML template as <disk>.
'''
return BlockDevice(self.path, self.name, self.script,
self.rw, self.domain, self.devtype)
@property
def revisions(self):
''' Returns a dict containing revision identifiers and time of their
creation '''
msg = "{!s} has revisions not implemented".format(self.__class__)
raise NotImplementedError(msg)
@property
def size(self):
''' Volume size in bytes '''
return self._size
@size.setter
def size(self, size):
# pylint: disable=attribute-defined-outside-init
self._size = int(size)
@property
def config(self):
''' return config data for serialization to qubes.xml '''
result = {
'name': self.name,
'pool': str(self.pool),
'vid': self.vid,
'revisions_to_keep': self.revisions_to_keep,
'rw': self.rw,
'save_on_stop': self.save_on_stop,
'snap_on_start': self.snap_on_start,
}
if self.size:
result['size'] = self.size
if self.source:
result['source'] = str(self.source)
return result
def _not_implemented(self, method_name):
''' Helper for emitting helpful `NotImplementedError` exceptions '''
msg = "Volume {!s} has {!s}() not implemented"
msg = msg.format(str(self.__class__.__name__), method_name)
return NotImplementedError(msg)
class Storage(object):
''' Class for handling VM virtual disks.
This is base class for all other implementations, mostly with Xen on Linux
in mind.
'''
AVAILABLE_FRONTENDS = set(['xvd' + c for c in string.ascii_lowercase])
def __init__(self, vm):
#: Domain for which we manage storage
self.vm = vm
self.log = self.vm.log
#: Additional drive (currently used only by HVM)
self.drive = None
if hasattr(vm, 'volume_config'):
for name, conf in self.vm.volume_config.items():
self.init_volume(name, conf)
def _update_volume_config_source(self, name, volume_config):
'''Retrieve 'source' volume from VM's template'''
template = getattr(self.vm, 'template', None)
# recursively lookup source volume - templates may be
# chained (TemplateVM -> AppVM -> DispVM, where the
# actual source should be used from TemplateVM)
while template:
source = template.volumes[name]
volume_config['source'] = source
volume_config['pool'] = source.pool
volume_config['size'] = source.size
if source.source is not None:
template = getattr(template, 'template', None)
else:
break
def init_volume(self, name, volume_config):
''' Initialize Volume instance attached to this domain '''
if 'name' not in volume_config:
volume_config['name'] = name
if 'source' in volume_config:
# we have no control over VM load order,
# so initialize storage recursively if needed
template = getattr(self.vm, 'template', None)
if template and template.storage is None:
template.storage = Storage(template)
if volume_config['source'] is None:
self._update_volume_config_source(name, volume_config)
else:
# if source is already specified, pool needs to be too
pool = self.vm.app.get_pool(volume_config['pool'])
volume_config['source'] = pool.volumes[volume_config['source']]
# if pool still unknown, load default
if 'pool' not in volume_config:
volume_config['pool'] = \
getattr(self.vm.app, 'default_pool_' + name)
pool = self.vm.app.get_pool(volume_config['pool'])
if 'internal' in volume_config:
# migrate old config
del volume_config['internal']
volume = pool.init_volume(self.vm, volume_config)
self.vm.volumes[name] = volume
return volume
def attach(self, volume, rw=False):
''' Attach a volume to the domain '''
assert self.vm.is_running()
if self._is_already_attached(volume):
self.vm.log.info("{!r} already attached".format(volume))
return
try:
frontend = self.unused_frontend()
except IndexError:
raise StoragePoolException("No unused frontend found")
disk = lxml.etree.Element("disk")
disk.set('type', 'block')
disk.set('device', 'disk')
lxml.etree.SubElement(disk, 'driver').set('name', 'phy')
lxml.etree.SubElement(disk, 'source').set('dev', '/dev/%s' % volume.vid)
lxml.etree.SubElement(disk, 'target').set('dev', frontend)
if not rw:
lxml.etree.SubElement(disk, 'readonly')
if volume.domain is not None:
lxml.etree.SubElement(disk, 'backenddomain').set(
'name', volume.domain.name)
xml_string = lxml.etree.tostring(disk, encoding='utf-8')
self.vm.libvirt_domain.attachDevice(xml_string)
# trigger watches to update device status
# FIXME: this should be removed once libvirt will report such
# events itself
# self.vm.untrusted_qdb.write('/qubes-block-devices', '')
# ← do we need this?
def _is_already_attached(self, volume):
''' Checks if the given volume is already attached '''
parsed_xml = lxml.etree.fromstring(self.vm.libvirt_domain.XMLDesc())
disk_sources = parsed_xml.xpath("//domain/devices/disk/source")
for source in disk_sources:
if source.get('dev') == '/dev/%s' % volume.vid:
return True
return False
def detach(self, volume):
''' Detach a volume from domain '''
parsed_xml = lxml.etree.fromstring(self.vm.libvirt_domain.XMLDesc())
disks = parsed_xml.xpath("//domain/devices/disk")
for disk in disks:
source = disk.xpath('source')[0]
if source.get('dev') == '/dev/%s' % volume.vid:
disk_xml = lxml.etree.tostring(disk, encoding='utf-8')
self.vm.libvirt_domain.detachDevice(disk_xml)
return
raise StoragePoolException('Volume {!r} is not attached'.format(volume))
@property
def kernels_dir(self):
'''Directory where kernel resides.
If :py:attr:`self.vm.kernel` is :py:obj:`None`, the this points inside
:py:attr:`self.vm.dir_path`
'''
assert 'kernel' in self.vm.volumes, "VM has no kernel volume"
return self.vm.volumes['kernel'].kernels_dir
def get_disk_utilization(self):
''' Returns summed up disk utilization for all domain volumes '''
result = 0
for volume in self.vm.volumes.values():
result += volume.usage
return result
@asyncio.coroutine
def resize(self, volume, size):
''' Resizes volume a read-writable volume '''
if isinstance(volume, str):
volume = self.vm.volumes[volume]
ret = volume.resize(size)
if asyncio.iscoroutine(ret):
yield from ret
if self.vm.is_running():
try:
yield from self.vm.run_service_for_stdio('qubes.ResizeDisk',
input=volume.name.encode(),
user='root')
except subprocess.CalledProcessError as e:
service_error = e.stderr.decode('ascii', errors='ignore')
service_error = service_error.replace('%', '')
raise StoragePoolException(
'Online resize of volume {} failed (you need to resize '
'filesystem manually): {}'.format(volume, service_error))
@asyncio.coroutine
def create(self):
''' Creates volumes on disk '''
old_umask = os.umask(0o002)
coros = []
for volume in self.vm.volumes.values():
# launch the operation, if it's asynchronous, then append to wait
# for them at the end
ret = volume.create()
if asyncio.iscoroutine(ret):
coros.append(ret)
if coros:
yield from asyncio.wait(coros)
os.umask(old_umask)
@asyncio.coroutine
def clone_volume(self, src_vm, name):
''' Clone single volume from the specified vm
:param QubesVM src_vm: source VM
:param str name: name of volume to clone ('root', 'private' etc)
:return cloned volume object
'''
config = self.vm.volume_config[name]
dst_pool = self.vm.app.get_pool(config['pool'])
dst = dst_pool.init_volume(self.vm, config)
src_volume = src_vm.volumes[name]
msg = "Importing volume {!s} from vm {!s}"
self.vm.log.info(msg.format(src_volume.name, src_vm.name))
# First create the destination volume
create_op_ret = dst.create()
# clone/import functions may be either synchronous or asynchronous
# in the later case, we need to wait for them to finish
if asyncio.iscoroutine(create_op_ret):
yield from create_op_ret
# Then import data from source volume
clone_op_ret = dst.import_volume(src_volume)
# clone/import functions may be either synchronous or asynchronous
# in the later case, we need to wait for them to finish
if asyncio.iscoroutine(clone_op_ret):
yield from clone_op_ret
self.vm.volumes[name] = dst
return self.vm.volumes[name]
@asyncio.coroutine
def clone(self, src_vm):
''' Clone volumes from the specified vm '''
self.vm.volumes = {}
with VmCreationManager(self.vm):
yield from asyncio.wait([self.clone_volume(src_vm, vol_name)
for vol_name in self.vm.volume_config.keys()])
@property
def outdated_volumes(self):
''' Returns a list of outdated volumes '''
result = []
if self.vm.is_halted():
return result
volumes = self.vm.volumes
for volume in volumes.values():
if volume.is_outdated():
result += [volume]
return result
@asyncio.coroutine
def verify(self):
'''Verify that the storage is sane.
On success, returns normally. On failure, raises exception.
'''
if not os.path.exists(self.vm.dir_path):
raise qubes.exc.QubesVMError(
self.vm,
'VM directory does not exist: {}'.format(self.vm.dir_path))
futures = []
for volume in self.vm.volumes.values():
ret = volume.verify()
if asyncio.iscoroutine(ret):
futures.append(ret)
if futures:
done, _ = yield from asyncio.wait(futures)
for task in done:
# re-raise any exception from async task
task.result()
self.vm.fire_event('domain-verify-files')
return True
@asyncio.coroutine
def remove(self):
''' Remove all the volumes.
Errors on removal are catched and logged.
'''
futures = []
for name, volume in self.vm.volumes.items():
self.log.info('Removing volume %s: %s' % (name, volume.vid))
try:
ret = volume.remove()
if asyncio.iscoroutine(ret):
futures.append(ret)
except (IOError, OSError) as e:
self.vm.log.exception("Failed to remove volume %s", name, e)
if futures:
try:
done, _ = yield from asyncio.wait(futures)
for task in done:
# re-raise any exception from async task
task.result()
except (IOError, OSError) as e:
self.vm.log.exception("Failed to remove some volume", e)
@asyncio.coroutine
def start(self):
''' Execute the start method on each pool '''
futures = []
for volume in self.vm.volumes.values():
ret = volume.start()
if asyncio.iscoroutine(ret):
futures.append(ret)
if futures:
done, _ = yield from asyncio.wait(futures)
for task in done:
# re-raise any exception from async task
task.result()
@asyncio.coroutine
def stop(self):
''' Execute the start method on each pool '''
futures = []
for volume in self.vm.volumes.values():
ret = volume.stop()
if asyncio.iscoroutine(ret):
futures.append(ret)
if futures:
done, _ = yield from asyncio.wait(futures)
for task in done:
# re-raise any exception from async task
task.result()
def unused_frontend(self):
''' Find an unused device name '''
unused_frontends = self.AVAILABLE_FRONTENDS.difference(
self.used_frontends)
return sorted(unused_frontends)[0]
@property
def used_frontends(self):
''' Used device names '''
xml = self.vm.libvirt_domain.XMLDesc()
parsed_xml = lxml.etree.fromstring(xml)
return set([target.get('dev', None)
for target in parsed_xml.xpath(
"//domain/devices/disk/target")])
def export(self, volume):
''' Helper function to export volume (pool.export(volume))'''
assert isinstance(volume, (Volume, str)), \
"You need to pass a Volume or pool name as str"
if isinstance(volume, Volume):
return volume.export()
return self.vm.volumes[volume].export()
def import_data(self, volume):
''' Helper function to import volume data (pool.import_data(volume))'''
assert isinstance(volume, (Volume, str)), \
"You need to pass a Volume or pool name as str"
if isinstance(volume, Volume):
return volume.import_data()
return self.vm.volumes[volume].import_data()
def import_data_end(self, volume, success):
''' Helper function to finish/cleanup data import
(pool.import_data_end( volume))'''
assert isinstance(volume, (Volume, str)), \
"You need to pass a Volume or pool name as str"
if isinstance(volume, Volume):
return volume.import_data_end(success=success)
return self.vm.volumes[volume].import_data_end(success=success)
class VolumesCollection(object):
'''Convenient collection wrapper for pool.get_volume and
pool.list_volumes
'''
def __init__(self, pool):
self._pool = pool
def __getitem__(self, item):
''' Get a single volume with given Volume ID.
You can also a Volume instance to get the same Volume or KeyError if
Volume no longer exists.
:param item: a Volume ID (str) or a Volume instance
'''
if isinstance(item, Volume):
if item.pool == self._pool:
return self[item.vid]
else:
raise KeyError(item)
try:
return self._pool.get_volume(item)
except NotImplementedError:
for vol in self:
if vol.vid == item:
return vol
# if list_volumes is not implemented too, it will raise
# NotImplementedError again earlier
raise KeyError(item)
def __iter__(self):
''' Get iterator over pool's volumes '''
return iter(self._pool.list_volumes())
def __contains__(self, item):
''' Check if given volume (either Volume ID or Volume instance) is
present in the pool
'''
try:
return self[item] is not None
except KeyError:
return False
def keys(self):
''' Return list of volume IDs '''
return [vol.vid for vol in self]
def values(self):
''' Return list of Volumes'''
return [vol for vol in self]
class Pool(object):
''' A Pool is used to manage different kind of volumes (File
based/LVM/Btrfs/...).
3rd Parties providing own storage implementations will need to extend
this class.
''' # pylint: disable=unused-argument
private_img_size = qubes.config.defaults['private_img_size']
root_img_size = qubes.config.defaults['root_img_size']
def __init__(self, name, revisions_to_keep=1, **kwargs):
super(Pool, self).__init__(**kwargs)
self._volumes_collection = VolumesCollection(self)
self.name = name
self.revisions_to_keep = revisions_to_keep
kwargs['name'] = self.name
def __eq__(self, other):
if isinstance(other, Pool):
return self.name == other.name
elif isinstance(other, str):
return self.name == other
return NotImplemented
def __neq__(self, other):
return not self.__eq__(other)
def __str__(self):
return self.name
def __hash__(self):
return hash(self.name)
def __xml__(self):
config = _sanitize_config(self.config)
return lxml.etree.Element('pool', **config)
@property
def config(self):
''' Returns the pool config to be written to qubes.xml '''
raise self._not_implemented("config")
def destroy(self):
''' Called when removing the pool. Use this for implementation specific
clean up.
'''
raise self._not_implemented("destroy")
def init_volume(self, vm, volume_config):
''' Initialize a :py:class:`qubes.storage.Volume` from `volume_config`.
'''
raise self._not_implemented("init_volume")
def setup(self):
''' Called when adding a pool to the system. Use this for implementation
specific set up.
'''
raise self._not_implemented("setup")
@property
def volumes(self):
''' Return a collection of volumes managed by this pool '''
return self._volumes_collection
def list_volumes(self):
''' Return a list of volumes managed by this pool '''
raise self._not_implemented("list_volumes")
def get_volume(self, vid):
''' Return a volume with *vid* from this pool
:raise KeyError: if no volume is found
'''
raise self._not_implemented("get_volume")
@property
def size(self):
''' Storage pool size in bytes '''
raise self._not_implemented("size")
@property
def usage(self):
''' Space used in the pool, in bytes '''
raise self._not_implemented("usage")
def _not_implemented(self, method_name):
''' Helper for emitting helpful `NotImplementedError` exceptions '''
msg = "Pool driver {!s} has {!s}() not implemented"
msg = msg.format(str(self.__class__.__name__), method_name)
return NotImplementedError(msg)
def _sanitize_config(config):
''' Helper function to convert types to appropriate strings
''' # FIXME: find another solution for serializing basic types
result = {}
for key, value in config.items():
if isinstance(value, bool):
if value:
result[key] = 'True'
else:
result[key] = str(value)
return result
def pool_drivers():
""" Return a list of EntryPoints names """
return [ep.name
for ep in pkg_resources.iter_entry_points(STORAGE_ENTRY_POINT)]
def driver_parameters(name):
''' Get __init__ parameters from a driver with out `self` & `name`. '''
init_function = qubes.utils.get_entry_point_one(
qubes.storage.STORAGE_ENTRY_POINT, name).__init__
signature = inspect.signature(init_function)
params = signature.parameters.keys()
ignored_params = ['self', 'name', 'kwargs']
return [p for p in params if p not in ignored_params]
def isodate(seconds=time.time()):
''' Helper method which returns an iso date '''
return datetime.utcfromtimestamp(seconds).isoformat("T")
class VmCreationManager(object):
''' A `ContextManager` which cleans up if volume creation fails.
''' # pylint: disable=too-few-public-methods
def __init__(self, vm):
self.vm = vm
def __enter__(self):
pass
def __exit__(self, type, value, tb): # pylint: disable=redefined-builtin
if type is not None and value is not None and tb is not None:
for volume in self.vm.volumes.values():
try:
volume.remove()
except Exception: # pylint: disable=broad-except
pass
os.rmdir(self.vm.dir_path)