core-admin/core/storage/__init__.py
2015-11-25 16:01:28 +01:00

406 line
13 KiB
Python

#!/usr/bin/python2
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2013 Marek Marczykowski <marmarek@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 os
import os.path
import shutil
import subprocess
import sys
import qubes.qubesutils
from qubes.qubes import QubesException, defaults, system_path
CONFIG_FILE = '/etc/qubes/storage.conf'
class QubesVmStorage(object):
"""
Class for handling VM virtual disks. This is base class for all other
implementations, mostly with Xen on Linux in mind.
"""
def __init__(self, vm,
private_img_size = None,
root_img_size = None,
modules_img = None,
modules_img_rw = False):
self.vm = vm
self.vmdir = vm.dir_path
if private_img_size:
self.private_img_size = private_img_size
else:
self.private_img_size = defaults['private_img_size']
if root_img_size:
self.root_img_size = root_img_size
else:
self.root_img_size = defaults['root_img_size']
self.root_dev = "xvda"
self.private_dev = "xvdb"
self.volatile_dev = "xvdc"
self.modules_dev = "xvdd"
# For now compute this path still in QubesVm
self.modules_img = modules_img
self.modules_img_rw = modules_img_rw
# Additional drive (currently used only by HVM)
self.drive = None
def format_disk_dev(self, path, script, vdev, rw=True, type="disk",
domain=None):
if path is None:
return ''
template = " <disk type='block' device='{type}'>\n" \
" <driver name='phy'/>\n" \
" <source dev='{path}'/>\n" \
" <target dev='{vdev}' bus='xen'/>\n" \
"{params}" \
" </disk>\n"
params = ""
if not rw:
params += " <readonly/>\n"
if domain:
params += " <backenddomain name='%s'/>\n" % domain
if script:
params += " <script path='%s'/>\n" % script
return template.format(path=path, vdev=vdev, type=type, params=params)
def get_config_params(self):
raise NotImplementedError
def _copy_file(self, 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
retcode = subprocess.call (["cp", "--reflink=auto", source, destination])
if retcode != 0:
raise IOError ("Error while copying {0} to {1}".\
format(source, destination))
def get_disk_utilization(self):
return qubes.qubesutils.get_disk_usage(self.vmdir)
def get_disk_utilization_private_img(self):
return qubes.qubesutils.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, verbose, source_template = None):
raise NotImplementedError
def create_on_disk_root_img(self, verbose, source_template = None):
raise NotImplementedError
def create_on_disk(self, verbose, source_template = None):
if source_template is None:
source_template = self.vm.template
old_umask = os.umask(002)
if verbose:
print >> sys.stderr, "--> Creating directory: {0}".format(self.vmdir)
os.mkdir (self.vmdir)
self.create_on_disk_private_img(verbose, source_template)
self.create_on_disk_root_img(verbose, source_template)
self.reset_volatile_storage(verbose, source_template)
os.umask(old_umask)
def clone_disk_files(self, src_vm, verbose):
if verbose:
print >> sys.stderr, "--> Creating directory: {0}".format(self.vmdir)
os.mkdir (self.vmdir)
if src_vm.private_img is not None and self.private_img is not None:
if verbose:
print >> sys.stderr, "--> Copying the private image:\n{0} ==>\n{1}".\
format(src_vm.private_img, self.private_img)
self._copy_file(src_vm.private_img, self.private_img)
if src_vm.updateable and src_vm.root_img is not None and self.root_img is not None:
if verbose:
print >> sys.stderr, "--> Copying the root image:\n{0} ==>\n{1}".\
format(src_vm.root_img, self.root_img)
self._copy_file(src_vm.root_img, self.root_img)
# TODO: modules?
def rename(self, old_name, new_name):
old_vmdir = self.vmdir
new_vmdir = os.path.join(os.path.dirname(self.vmdir), new_name)
os.rename(self.vmdir, new_vmdir)
self.vmdir = new_vmdir
if self.private_img:
self.private_img = self.private_img.replace(old_vmdir, new_vmdir)
if self.root_img:
self.root_img = self.root_img.replace(old_vmdir, new_vmdir)
if self.volatile_img:
self.volatile_img = self.volatile_img.replace(old_vmdir, new_vmdir)
def verify_files(self):
if not os.path.exists (self.vmdir):
raise QubesException (
"VM directory doesn't exist: {0}".\
format(self.vmdir))
if self.root_img and not os.path.exists (self.root_img):
raise QubesException (
"VM root image file doesn't exist: {0}".\
format(self.root_img))
if self.private_img and not os.path.exists (self.private_img):
raise QubesException (
"VM private image file doesn't exist: {0}".\
format(self.private_img))
if self.modules_img is not None:
if not os.path.exists(self.modules_img):
raise QubesException (
"VM kernel modules image does not exists: {0}".\
format(self.modules_img))
def remove_from_disk(self):
shutil.rmtree (self.vmdir)
def reset_volatile_storage(self, verbose = False, 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 self.volatile_img and not os.path.exists(self.volatile_img):
if verbose:
print >> sys.stderr, "--> Creating volatile image: {0}...".\
format(self.volatile_img)
subprocess.check_call([system_path["prepare_volatile_img_cmd"],
self.volatile_img, str(self.root_img_size / 1024 / 1024)])
def prepare_for_vm_startup(self, verbose):
self.reset_volatile_storage(verbose=verbose)
if self.private_img and not os.path.exists (self.private_img):
print >>sys.stderr, "WARNING: Creating empty VM private image file: {0}".\
format(self.private_img)
self.create_on_disk_private_img(verbose=False)
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 load(string):
""" 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`
"""
if not type(string) is str:
# This is a hack which allows giving a real class to a vm instead of a
# string as string_class parameter.
return string
components = string.split(".")
module_path = ".".join(components[:-1])
klass = components[-1:][0]
module = __import__(module_path, fromlist=[klass])
return getattr(module, klass)
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 = 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 = defaults['pool_drivers'][pool_driver]
else:
raise StoragePoolException('Uknown storage pool driver ' + name)
return klass
class StoragePoolException(QubesException):
pass
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)
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')
else:
raise QubesException(vm.type() + ' unknown vm type')
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)