core-admin/qubes/storage/lvm.py

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# vim: fileencoding=utf-8
# pylint: disable=abstract-method
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2016 Bahtiar `kalkin-` Gadimov <bahtiar@gadimov.de>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
''' Driver for storing vm images in a LVM thin pool '''
import logging
import os
import subprocess
import qubes
class ThinPool(qubes.storage.Pool):
''' LVM Thin based pool implementation
''' # pylint: disable=protected-access
driver = 'lvm_thin'
def __init__(self, volume_group, thin_pool, **kwargs):
super(ThinPool, self).__init__(**kwargs)
self.volume_group = volume_group
self.thin_pool = thin_pool
self._pool_id = "{!s}/{!s}".format(volume_group, thin_pool)
self.log = logging.getLogger('qube.storage.lvm.%s' % self._pool_id)
def backup(self, volume):
msg = "Expected volume_type 'snap' got {!s}"
msg = msg.format(volume.volume_type)
assert volume.volume_type == 'snap', msg
cmd = ['remove', volume.vid + "-back"]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume.vid, volume.vid + "-back"]
qubes_lvm(cmd, self.log)
volume.backups = [volume.vid + "-back"]
return volume
def clone(self, source, target):
cmd = ['clone', source.vid, target.vid]
qubes_lvm(cmd, self.log)
return target
def commit(self, volume):
msg = "Expected rw:True & volume_type 'snap' got {!s} & rw:{!s}"
msg = msg.format(volume.volume_type, volume.rw)
assert volume.volume_type == 'snap' and volume.rw, msg
assert volume.path.endswith("-snap")
self.backup(volume)
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume.path, volume.vid]
qubes_lvm(cmd, self.log)
def _backup(self, volume):
msg = "Expected volume_type 'snap' got {!s}"
msg = msg.format(volume.volume_type)
assert volume.volume_type == 'snap', msg
cmd = ['remove', volume.vid + "-back"]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume.vid, volume.vid + "-back"]
qubes_lvm(cmd, self.log)
volume.backups = [volume.vid + "-back"]
return 'XXX'
@property
def config(self):
return {
'name': self.name,
'volume_group': self.volume_group,
'thin_pool': self.thin_pool,
'driver': ThinPool.driver
}
def create(self, volume):
assert volume.vid
assert volume.size
if volume.source:
return self.clone(volume.source, volume)
else:
cmd = [
'create',
self._pool_id,
volume.vid.split('/', 1)[1],
str(volume.size)
]
qubes_lvm(cmd, self.log)
return volume
def destroy(self):
pass # TODO Should we remove an existing pool?
def export(self, volume):
''' Returns an object that can be `open()`. '''
return '/dev/' + volume.vid
def init_volume(self, vm, volume_config):
''' Initialize a :py:class:`qubes.storage.Volume` from `volume_config`.
'''
if 'vid' not in volume_config.keys():
if vm and hasattr(vm, 'name'):
vm_name = vm.name
else:
# for the future if we have volumes not belonging to a vm
vm_name = qubes.utils.random_string()
assert self.name
volume_config['vid'] = "{!s}/{!s}-{!s}".format(
self.volume_group, vm_name, volume_config['name'])
volume_config['volume_group'] = self.volume_group
return ThinVolume(**volume_config)
def import_volume(self, dst_pool, dst_volume, src_pool, src_volume):
src_path = src_pool.export(src_volume)
# HACK: neat trick to speed up testing if you have same physical thin
# pool assigned to two qubes-pools i.e: qubes_dom0 and test-lvm
# pylint: disable=line-too-long
if isinstance(src_pool, ThinPool) and src_pool.thin_pool == dst_pool.thin_pool: # NOQA
return self.clone(src_volume, dst_volume)
else:
dst_volume = self.create(dst_volume)
cmd = ['sudo', 'qubes-lvm', 'import', dst_volume.vid]
blk_size = 4096
p = subprocess.Popen(cmd, stdin=subprocess.PIPE)
dst = p.stdin
with open(src_path, 'rb') as src:
while True:
tmp = src.read(blk_size)
if not tmp:
break
else:
dst.write(tmp)
p.stdin.close()
p.wait()
return dst_volume
def is_dirty(self, volume):
if volume.save_on_stop:
return os.path.exists(volume.path + '-snap')
return False
def remove(self, volume):
assert volume.vid
if self.is_dirty(volume):
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
def rename(self, volume, old_name, new_name):
''' Called when the domain changes its name '''
new_vid = "{!s}/{!s}-{!s}".format(self.volume_group, new_name,
volume.name)
if volume.save_on_stop:
cmd = ['clone', volume.vid, new_vid]
qubes_lvm(cmd, self.log)
if volume.save_on_stop or volume._is_volatile:
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
volume.vid = new_vid
if not volume._is_volatile:
volume._vid_snap = volume.vid + '-snap'
return volume
def _reset(self, volume):
self.remove(volume)
self.create(volume)
def setup(self):
pass # TODO Should we create a non existing pool?gt
def start(self, volume):
if volume._is_snapshot:
self._snapshot(volume)
elif volume._is_volatile:
self._reset(volume)
else:
if not self.is_dirty(volume):
self._snapshot(volume)
return volume
def stop(self, volume):
if volume.save_on_stop:
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume._vid_snap, volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
elif volume._is_volatile:
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
else:
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
def _snapshot(self, volume):
if volume.source is None:
cmd = ['clone', volume.vid, volume._vid_snap]
else:
cmd = ['clone', str(volume.source), volume._vid_snap]
qubes_lvm(cmd, self.log)
def verify(self, volume):
''' Verifies the volume. '''
cmd = ['sudo', 'qubes-lvm', 'volumes',
self.volume_group + '/' + self.thin_pool]
p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
result = p.communicate()[0]
for line in result.splitlines():
if not line.strip():
continue
vid, atr = line.strip().split(' ')
if vid == volume.vid:
return atr[4] == 'a'
return False
@property
def volumes(self):
''' Return a list of volumes managed by this pool '''
cmd = ['sudo', 'qubes-lvm', 'volumes',
self.volume_group + '/' + self.thin_pool]
p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
result = p.communicate()[0]
volumes = []
for line in result.splitlines():
if not line.strip():
continue
vid, atr = line.strip().split(' ')
config = {
'pool': self.name,
'vid': vid,
'name': vid,
'volume_group': self.volume_group,
'rw': atr[1] == 'w',
}
volumes += [ThinVolume(**config)]
return volumes
def _reset_volume(self, volume):
''' Resets a volatile volume '''
assert volume.volume_type == 'volatile', \
'Expected a volatile volume, but got {!r}'.format(volume)
self.log.debug('Resetting volatile ' + volume.vid)
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['create', self._pool_id, volume.vid.split('/')[1],
str(volume.size)]
qubes_lvm(cmd, self.log)
class ThinVolume(qubes.storage.Volume):
''' Default LVM thin volume implementation
''' # pylint: disable=too-few-public-methods
def __init__(self, volume_group, **kwargs):
self.volume_group = volume_group
super(ThinVolume, self).__init__(**kwargs)
if self.snap_on_start and self.source is None:
msg = "snap_on_start specified on {!r} but no volume source set"
msg = msg.format(self.name)
raise qubes.storage.StoragePoolException(msg)
elif not self.snap_on_start and self.source is not None:
msg = "source specified on {!r} but no snap_on_start set"
msg = msg.format(self.name)
raise qubes.storage.StoragePoolException(msg)
self.path = '/dev/' + self.vid
if not self._is_volatile:
self._vid_snap = self.vid + '-snap'
@property
def revisions(self):
return {}
@property
def _is_origin(self):
return not self.snap_on_start and self.save_on_stop
@property
def _is_origin_snapshot(self):
return self.snap_on_start and self.save_on_stop
@property
def _is_snapshot(self):
return self.snap_on_start and not self.save_on_stop
@property
def _is_volatile(self):
return not self.snap_on_start and not self.save_on_stop
def pool_exists(pool_id):
''' Return true if pool exists '''
cmd = ['pool', pool_id]
return qubes_lvm(cmd)
def qubes_lvm(cmd, log=logging.getLogger('qube.storage.lvm')):
''' Call :program:`qubes-lvm` to execute an LVM operation '''
# TODO Refactor this ones the udev groups gets fixed and we don't need root
# for operations on lvm devices
cmd = ['sudo', 'qubes-lvm'] + cmd
p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
out, err = p.communicate()
return_code = p.returncode
if out:
log.info(out)
if return_code == 0 and err:
log.warning(err)
elif return_code != 0:
assert err, "Command exited unsuccessful, but printed nothing to stderr"
raise qubes.storage.StoragePoolException(err)
return True