#!/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 os
import os.path
import re
import subprocess
import sys
from qubes.qubes import QubesException, vm_files
from qubes.storage import Pool, QubesVmStorage
class XenStorage(QubesVmStorage):
"""
Class for VM storage of Xen VMs.
"""
def __init__(self, vm, vmdir, **kwargs):
""" Instantiate the storage.
Args:
vm: a QubesVM
vmdir: the root directory of the pool
"""
assert vm is not None
assert vmdir is not None
super(XenStorage, self).__init__(vm, **kwargs)
self.vmdir = vmdir
if self.vm.is_template():
self.rootcow_img = os.path.join(self.vmdir,
vm_files["rootcow_img"])
else:
self.rootcow_img = None
self.private_img = os.path.join(vmdir, 'private.img')
if self.vm.template:
self.root_img = self.vm.template.root_img
else:
self.root_img = os.path.join(vmdir, 'root.img')
self.volatile_img = os.path.join(vmdir, 'volatile.img')
def root_dev_config(self):
if self.vm.is_template() and self.rootcow_img:
return self.format_disk_dev(
"{root}:{rootcow}".format(
root=self.root_img, rootcow=self.rootcow_img),
"block-origin", self.root_dev, True)
elif self.vm.template and not hasattr(self.vm, 'kernel'):
# HVM template-based VM - only one device-mapper layer, in dom0 (
# root+volatile)
# HVM detection based on 'kernel' property is massive hack,
# but taken from assumption that VM needs Qubes-specific kernel (
# actually initramfs) to assemble the second layer of device-mapper
return self.format_disk_dev(
"{root}:{volatile}".format(
root=self.vm.template.storage.root_img,
volatile=self.volatile_img),
"block-snapshot", self.root_dev, True)
elif self.vm.template:
# any other template-based VM - two device-mapper layers: one
# in dom0 (here) from root+root-cow, and another one from
# this+volatile.img
return self.format_disk_dev(
"{root}:{rootcow}".format(
root=self.root_img,
rootcow=self.vm.template.storage.rootcow_img),
"block-snapshot", self.root_dev, False)
else:
return self.format_disk_dev(
"{root}".format(root=self.root_img),
None, self.root_dev, True)
def private_dev_config(self):
return self.format_disk_dev(self.private_img, None,
self.private_dev, True)
def volatile_dev_config(self):
return self.format_disk_dev(self.volatile_img, None,
self.volatile_dev, True)
def create_on_disk_private_img(self, verbose, source_template = None):
if source_template:
template_priv = source_template.private_img
if verbose:
print >> sys.stderr, "--> Copying the template's private image: {0}".\
format(template_priv)
self._copy_file(template_priv, self.private_img)
else:
f_private = open (self.private_img, "a+b")
f_private.truncate (self.private_img_size)
f_private.close ()
def create_on_disk_root_img(self, verbose, source_template = None):
if source_template:
if not self.vm.updateable:
# just use template's disk
return
else:
template_root = source_template.root_img
if verbose:
print >> sys.stderr, "--> Copying the template's root image: {0}".\
format(template_root)
self._copy_file(template_root, self.root_img)
else:
f_root = open (self.root_img, "a+b")
f_root.truncate (self.root_img_size)
f_root.close ()
if self.vm.is_template():
self.commit_template_changes()
def rename(self, old_name, new_name):
super(XenStorage, self).rename(old_name, new_name)
old_dirpath = os.path.join(os.path.dirname(self.vmdir), old_name)
if self.rootcow_img:
self.rootcow_img = self.rootcow_img.replace(old_dirpath,
self.vmdir)
def resize_private_img(self, size):
f_private = open (self.private_img, "a+b")
f_private.truncate (size)
f_private.close ()
# find loop device if any
p = subprocess.Popen (["sudo", "losetup", "--associated", self.private_img],
stdout=subprocess.PIPE)
result = p.communicate()
m = re.match(r"^(/dev/loop\d+):\s", result[0])
if m is not None:
loop_dev = m.group(1)
# resize loop device
subprocess.check_call(["sudo", "losetup", "--set-capacity", loop_dev])
def commit_template_changes(self):
assert self.vm.is_template()
if not self.rootcow_img:
return
if os.path.exists (self.rootcow_img):
os.rename (self.rootcow_img, self.rootcow_img + '.old')
old_umask = os.umask(002)
f_cow = open (self.rootcow_img, "w")
f_root = open (self.root_img, "r")
f_root.seek(0, os.SEEK_END)
f_cow.truncate (f_root.tell()) # make empty sparse file of the same size as root.img
f_cow.close ()
f_root.close()
os.umask(old_umask)
def reset_volatile_storage(self, verbose = False, source_template = None):
if source_template is None:
source_template = self.vm.template
if source_template is not None:
# template-based VM with only one device-mapper layer -
# volatile.img used as upper layer on root.img, no root-cow.img
# intermediate layer
if not source_template.storage.rootcow_img:
if os.path.exists(self.volatile_img):
if self.vm.debug:
if os.path.getmtime(source_template.storage.root_img)\
> os.path.getmtime(self.volatile_img):
if verbose:
print >>sys.stderr, "--> WARNING: template have changed, resetting root.img"
else:
if verbose:
print >>sys.stderr, "--> Debug mode: not resetting root.img"
print >>sys.stderr, "--> Debug mode: if you want to force root.img reset, either update template VM, or remove volatile.img file"
return
os.remove(self.volatile_img)
f_volatile = open(self.volatile_img, "w")
f_root = open(source_template.storage.root_img, "r")
f_root.seek(0, os.SEEK_END)
f_volatile.truncate(f_root.tell()) # make empty sparse file of the same size as root.img
f_volatile.close()
f_root.close()
return
super(XenStorage, self).reset_volatile_storage(
verbose=verbose, source_template=source_template)
def prepare_for_vm_startup(self, verbose):
super(XenStorage, self).prepare_for_vm_startup(verbose=verbose)
if self.drive is not None:
(drive_type, drive_domain, drive_path) = self.drive.split(":")
if drive_domain.lower() != "dom0":
try:
# FIXME: find a better way to access QubesVmCollection
drive_vm = self.vm._collection.get_vm_by_name(drive_domain)
# prepare for improved QubesVmCollection
if drive_vm is None:
raise KeyError
if not drive_vm.is_running():
raise QubesException(
"VM '{}' holding '{}' isn't running".format(
drive_domain, drive_path))
except KeyError:
raise QubesException(
"VM '{}' holding '{}' does not exists".format(
drive_domain, drive_path))
if self.rootcow_img and not os.path.exists(self.rootcow_img):
self.commit_template_changes()
class XenPool(Pool):
def __init__(self, vm, dir_path):
super(XenPool, self).__init__(vm, dir_path)
def getStorage(self):
""" Returns an instantiated ``XenStorage``. """
return XenStorage(self.vm, vmdir=self.vmdir)