core-admin/qubes/storage/__init__.py
Marek Marczykowski-Górecki 3af71ab65d storage: fix handling netvm and adminvm
@woju what was consensus on 'servicevms' dir? Since "being network
provider" is no longer separate type and can be changed during VM
lifetime, maybe we should abandon that idea? Or maybe just set it as VM
property (some storage pool config argument) - that way mgmt stack could
put all the sys-* VMs into separate directory, regardless of the type.
2016-03-03 01:18:06 +01:00

544 lines
16 KiB
Python

#!/usr/bin/python2 -O
# vim: fileencoding=utf-8
#
# 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 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.
#
from __future__ import absolute_import
import ConfigParser
import importlib
import os
import os.path
import re
import shutil
import subprocess
import sys
import qubes
import qubes.exc
import qubes.utils
BLKSIZE = 512
CONFIG_FILE = '/etc/qubes/storage.conf'
class StoragePoolException(qubes.exc.QubesException):
pass
class Storage(object):
'''Class for handling VM virtual disks.
This is base class for all other implementations, mostly with Xen on Linux
in mind.
'''
root_img = None
private_img = None
volatile_img = None
modules_dev = None
def __init__(self, vm, private_img_size=None, root_img_size=None):
#: Domain for which we manage storage
self.vm = vm
#: Size of the private image
self.private_img_size = private_img_size \
if private_img_size is not None \
else qubes.config.defaults['private_img_size']
#: Size of the root image
self.root_img_size = root_img_size \
if root_img_size is not None \
else qubes.config.defaults['root_img_size']
#: Additional drive (currently used only by HVM)
self.drive = None
def get_config_params(self):
args = {}
args['rootdev'] = self.root_dev_config()
args['privatedev'] = self.private_dev_config()
args['volatiledev'] = self.volatile_dev_config()
args['otherdevs'] = self.other_dev_config()
args['kerneldir'] = self.kernels_dir
return args
def root_dev_config(self):
raise NotImplementedError()
def private_dev_config(self):
raise NotImplementedError()
def volatile_dev_config(self):
raise NotImplementedError()
def other_dev_config(self):
if self.modules_img is not None:
return self.format_disk_dev(self.modules_img, self.modules_dev,
rw=self.modules_img_rw)
elif self.drive is not None:
(drive_type, drive_domain, drive_path) = self.drive.split(":")
if drive_type == 'hd':
drive_type = 'disk'
rw = (drive_type == 'disk')
if drive_domain.lower() == "dom0":
drive_domain = None
return self.format_disk_dev(drive_path,
self.modules_dev,
rw=rw,
devtype=drive_type,
domain=drive_domain)
else:
return ''
def format_disk_dev(self, path, vdev, script=None, rw=True, devtype='disk',
domain=None):
raise NotImplementedError()
@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`
'''
return os.path.join(qubes.config.system_path['qubes_base_dir'],
qubes.config.system_path['qubes_kernels_base_dir'], self.vm.kernel)\
if self.vm.kernel is not None \
else os.path.join(self.vm.dir_path,
qubes.config.vm_files['kernels_subdir'])
@property
def modules_img(self):
'''Path to image with modules.
Depending on domain, this may be global or inside domain's dir.
'''
modules_path = os.path.join(self.kernels_dir, 'modules.img')
if os.path.exists(modules_path):
return modules_path
else:
return None
@property
def modules_img_rw(self):
''':py:obj:`True` if module image should be mounted RW, :py:obj:`False`
otherwise.'''
return self.vm.kernel is None
def abspath(self, path, rel=None):
'''Make absolute path.
If given path is relative, it is interpreted as relative to
:py:attr:`self.vm.dir_path` or given *rel*.
'''
return path if os.path.isabs(path) \
else os.path.join(rel or self.vm.dir_path, path)
@staticmethod
def _copy_file(source, destination):
'''Effective file copy, preserving sparse files etc.
'''
# TODO: Windows support
# We prefer to use Linux's cp, because it nicely handles sparse files
try:
subprocess.check_call(['cp', '--reflink=auto', source, destination])
except subprocess.CalledProcessError:
raise IOError('Error while copying {!r} to {!r}'.format(
source, destination))
def get_disk_utilization(self):
return get_disk_usage(self.vm.dir_path)
def get_disk_utilization_private_img(self):
# pylint: disable=invalid-name
return get_disk_usage(self.private_img)
def get_private_img_sz(self):
if not os.path.exists(self.private_img):
return 0
return os.path.getsize(self.private_img)
def resize_private_img(self, size):
raise NotImplementedError()
def create_on_disk_private_img(self, source_template=None):
raise NotImplementedError()
def create_on_disk_root_img(self, source_template=None):
raise NotImplementedError()
def create_on_disk(self, source_template=None):
if source_template is None:
source_template = self.vm.template
old_umask = os.umask(002)
self.vm.log.info('Creating directory: {0}'.format(self.vm.dir_path))
os.mkdir(self.vm.dir_path)
self.create_on_disk_private_img(source_template)
self.create_on_disk_root_img(source_template)
self.reset_volatile_storage(source_template)
os.umask(old_umask)
def clone_disk_files(self, src_vm):
self.vm.log.info('Creating directory: {0}'.format(self.vm.dir_path))
os.mkdir(self.vm.dir_path)
if hasattr(src_vm, 'private_img'):
self.vm.log.info('Copying the private image: {} -> {}'.format(
src_vm.private_img, self.vm.private_img))
self._copy_file(src_vm.private_img, self.vm.private_img)
if src_vm.updateable and hasattr(src_vm, 'root_img'):
self.vm.log.info('Copying the root image: {} -> {}'.format(
src_vm.root_img, self.root_img))
self._copy_file(src_vm.root_img, self.root_img)
# TODO: modules?
# XXX which modules? -woju
@staticmethod
def rename(newpath, oldpath):
'''Move storage directory, most likely during domain's rename.
.. note::
The arguments are in different order than in :program:`cp` utility.
.. versionchange:: 4.0
This is now dummy method that just passes everything to
:py:func:`os.rename`.
:param str newpath: New path
:param str oldpath: Old path
'''
os.rename(oldpath, newpath)
def verify_files(self):
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))
if hasattr(self.vm, 'root_img') and not os.path.exists(self.root_img):
raise qubes.exc.QubesVMError(self.vm,
'VM root image file does not exist: {}'.format(self.root_img))
if hasattr(self.vm, 'private_img') \
and not os.path.exists(self.private_img):
raise qubes.exc.QubesVMError(self.vm,
'VM private image file does not exist: {}'.format(
self.private_img))
if self.modules_img is not None \
and not os.path.exists(self.modules_img):
raise qubes.exc.QubesVMError(self.vm,
'VM kernel modules image does not exists: {}'.format(
self.modules_img))
def remove_from_disk(self):
shutil.rmtree(self.vm.dir_path)
def reset_volatile_storage(self, source_template=None):
if source_template is None:
source_template = self.vm.template
# Re-create only for template based VMs
if source_template is not None and self.volatile_img:
if os.path.exists(self.volatile_img):
os.remove(self.volatile_img)
# For StandaloneVM create it only if not already exists
# (eg after backup-restore)
if hasattr(self, 'volatile_img') \
and not os.path.exists(self.vm.volatile_img):
self.vm.log.info(
'Creating volatile image: {0}'.format(self.volatile_img))
subprocess.check_call(
[qubes.config.system_path["prepare_volatile_img_cmd"],
self.volatile_img,
str(self.root_img_size / 1024 / 1024)])
def prepare_for_vm_startup(self):
self.reset_volatile_storage()
if hasattr(self.vm, 'private_img') \
and not os.path.exists(self.private_img):
self.vm.log.info('Creating empty VM private image file: {0}'.format(
self.private_img))
self.create_on_disk_private_img()
def get_disk_usage_one(st):
'''Extract disk usage of one inode from its stat_result struct.
If known, get real disk usage, as written to device by filesystem, not
logical file size. Those values may be different for sparse files.
:param os.stat_result st: stat result
:returns: disk usage
'''
try:
return st.st_blocks * BLKSIZE
except AttributeError:
return st.st_size
def get_disk_usage(path):
'''Get real disk usage of given path (file or directory).
When *path* points to directory, then it is evaluated recursively.
This function tries estiate real disk usage. See documentation of
:py:func:`get_disk_usage_one`.
:param str path: path to evaluate
:returns: disk usage
'''
try:
st = os.lstat(path)
except OSError:
return 0
ret = get_disk_usage_one(st)
# if path is not a directory, this is skipped
for dirpath, dirnames, filenames in os.walk(path):
for name in dirnames + filenames:
ret += get_disk_usage_one(os.lstat(os.path.join(dirpath, name)))
return ret
def load(clsname):
'''Given a dotted full module string representation of a class it loads it
Args:
string (str) i.e. 'qubes.storage.xen.QubesXenVmStorage'
Returns:
type
See also:
:func:`qubes.storage.dump`
:raises ImportError: when storage class specified in config cannot be found
:raises KeyError: when storage class specified in config cannot be found
'''
if not isinstance(clsname, basestring):
return clsname
pkg, cls = clsname.strip().rsplit('.', 1)
# this may raise ImportError or KeyError, that's okay
return importlib.import_module(pkg).__dict__[cls]
def dump(o):
""" Returns a string represention of the given object
Args:
o (object): anything that response to `__module__` and `__class__`
Given the class :class:`qubes.storage.QubesVmStorage` it returns
'qubes.storage.QubesVmStorage' as string
"""
return o.__module__ + '.' + o.__class__.__name__
def get_pool(name, vm):
""" Instantiates the storage for the specified vm """
config = _get_storage_config_parser()
klass = _get_pool_klass(name, config)
keys = [k for k in config.options(name) if k != 'driver' and k != 'class']
values = [config.get(name, o) for o in keys]
config_kwargs = dict(zip(keys, values))
if name == 'default':
kwargs = qubes.config.defaults['pool_config'].copy()
kwargs.update(keys)
else:
kwargs = config_kwargs
return klass(vm, **kwargs)
def pool_exists(name):
""" Check if the specified pool exists """
try:
_get_pool_klass(name)
return True
except StoragePoolException:
return False
def add_pool(name, **kwargs):
""" Add a storage pool to config."""
config = _get_storage_config_parser()
config.add_section(name)
for key, value in kwargs.iteritems():
config.set(name, key, value)
_write_config(config)
def remove_pool(name):
""" Remove a storage pool from config file. """
config = _get_storage_config_parser()
config.remove_section(name)
_write_config(config)
def _write_config(config):
with open(CONFIG_FILE, 'w') as configfile:
config.write(configfile)
def _get_storage_config_parser():
""" Instantiates a `ConfigParaser` for specified storage config file.
Returns:
RawConfigParser
"""
config = ConfigParser.RawConfigParser()
config.read(CONFIG_FILE)
return config
def _get_pool_klass(name, config=None):
""" Returns the storage klass for the specified pool.
Args:
name: The pool name.
config: If ``config`` is not specified
`_get_storage_config_parser()` is called.
Returns:
type: A class inheriting from `QubesVmStorage`
"""
if config is None:
config = _get_storage_config_parser()
if not config.has_section(name):
raise StoragePoolException('Uknown storage pool ' + name)
if config.has_option(name, 'class'):
klass = load(config.get(name, 'class'))
elif config.has_option(name, 'driver'):
pool_driver = config.get(name, 'driver')
klass = load(qubes.config.defaults['pool_drivers'][pool_driver])
else:
raise StoragePoolException('Uknown storage pool driver ' + name)
return klass
class Pool(object):
def __init__(self, vm, dir_path):
assert vm is not None
assert dir_path is not None
self.vm = vm
self.dir_path = dir_path
self.create_dir_if_not_exists(self.dir_path)
self.vmdir = self.vmdir_path(vm, self.dir_path)
appvms_path = os.path.join(self.dir_path, 'appvms')
self.create_dir_if_not_exists(appvms_path)
servicevms_path = os.path.join(self.dir_path, 'servicevms')
self.create_dir_if_not_exists(servicevms_path)
vm_templates_path = os.path.join(self.dir_path, 'vm-templates')
self.create_dir_if_not_exists(vm_templates_path)
# XXX there is also a class attribute on the domain classes which does
# exactly that -- which one should prevail?
def vmdir_path(self, vm, pool_dir):
""" Returns the path to vmdir depending on the type of the VM.
The default QubesOS file storage saves the vm images in three
different directories depending on the ``QubesVM`` type:
* ``appvms`` for ``QubesAppVm`` or ``QubesHvm``
* ``vm-templates`` for ``QubesTemplateVm`` or ``QubesTemplateHvm``
* ``servicevms`` for any subclass of ``QubesNetVm``
Args:
vm: a QubesVM
pool_dir: the root directory of the pool
Returns:
string (str) absolute path to the directory where the vm files
are stored
"""
if vm.is_appvm():
subdir = 'appvms'
elif vm.is_template():
subdir = 'vm-templates'
elif vm.is_netvm():
subdir = 'servicevms'
elif vm.is_disposablevm():
subdir = 'appvms'
return os.path.join(pool_dir, subdir, vm.template.name + '-dvm')
elif isinstance(vm, qubes.vm.adminvm.AdminVM):
subdir = 'servicevms'
else:
raise qubes.exc.QubesException(
'unknown vm type: {!r}'.format(str(vm.__class__)))
return os.path.join(pool_dir, subdir, vm.name)
def create_dir_if_not_exists(self, path):
""" Check if a directory exists in if not create it.
This method does not create any parent directories.
"""
if not os.path.exists(path):
os.mkdir(path)