35cb82cd2b
We still can't support running HVM template and its VMs simultaneously (easily), but still, have root-cow.img handled for HVM template, to allow qvm-revert-template-changes. Fixes QubesOS/qubes-issues#1573
239 lines
9.4 KiB
Python
239 lines
9.4 KiB
Python
#!/usr/bin/python2
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#
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# The Qubes OS Project, http://www.qubes-os.org
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#
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# Copyright (C) 2013 Marek Marczykowski <marmarek@invisiblethingslab.com>
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#
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License
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# as published by the Free Software Foundation; either version 2
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# of the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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# USA.
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#
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from __future__ import absolute_import
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import os
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import os.path
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import re
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import subprocess
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import sys
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from qubes.qubes import QubesException, vm_files
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from qubes.storage import Pool, QubesVmStorage
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class XenStorage(QubesVmStorage):
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"""
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Class for VM storage of Xen VMs.
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"""
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def __init__(self, vm, vmdir, **kwargs):
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""" Instantiate the storage.
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Args:
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vm: a QubesVM
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vmdir: the root directory of the pool
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"""
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assert vm is not None
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assert vmdir is not None
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super(XenStorage, self).__init__(vm, **kwargs)
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self.vmdir = vmdir
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if self.vm.is_template():
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self.rootcow_img = os.path.join(self.vmdir,
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vm_files["rootcow_img"])
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else:
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self.rootcow_img = None
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self.private_img = os.path.join(vmdir, 'private.img')
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if self.vm.template:
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self.root_img = self.vm.template.root_img
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else:
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self.root_img = os.path.join(vmdir, 'root.img')
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self.volatile_img = os.path.join(vmdir, 'volatile.img')
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def root_dev_config(self):
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if self.vm.is_template() and self.rootcow_img:
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return self.format_disk_dev(
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"{root}:{rootcow}".format(
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root=self.root_img, rootcow=self.rootcow_img),
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"block-origin", self.root_dev, True)
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elif self.vm.template and not hasattr(self.vm, 'kernel'):
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# HVM template-based VM - only one device-mapper layer, in dom0 (
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# root+volatile)
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# HVM detection based on 'kernel' property is massive hack,
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# but taken from assumption that VM needs Qubes-specific kernel (
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# actually initramfs) to assemble the second layer of device-mapper
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return self.format_disk_dev(
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"{root}:{volatile}".format(
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root=self.vm.template.storage.root_img,
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volatile=self.volatile_img),
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"block-snapshot", self.root_dev, True)
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elif self.vm.template:
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# any other template-based VM - two device-mapper layers: one
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# in dom0 (here) from root+root-cow, and another one from
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# this+volatile.img
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return self.format_disk_dev(
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"{root}:{rootcow}".format(
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root=self.root_img,
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rootcow=self.vm.template.storage.rootcow_img),
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"block-snapshot", self.root_dev, False)
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else:
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return self.format_disk_dev(
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"{root}".format(root=self.root_img),
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None, self.root_dev, True)
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def private_dev_config(self):
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return self.format_disk_dev(self.private_img, None,
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self.private_dev, True)
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def volatile_dev_config(self):
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return self.format_disk_dev(self.volatile_img, None,
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self.volatile_dev, True)
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def create_on_disk_private_img(self, verbose, source_template = None):
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if source_template:
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template_priv = source_template.private_img
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if verbose:
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print >> sys.stderr, "--> Copying the template's private image: {0}".\
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format(template_priv)
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self._copy_file(template_priv, self.private_img)
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else:
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f_private = open (self.private_img, "a+b")
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f_private.truncate (self.private_img_size)
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f_private.close ()
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def create_on_disk_root_img(self, verbose, source_template = None):
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if source_template:
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if not self.vm.updateable:
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# just use template's disk
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return
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else:
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template_root = source_template.root_img
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if verbose:
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print >> sys.stderr, "--> Copying the template's root image: {0}".\
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format(template_root)
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self._copy_file(template_root, self.root_img)
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else:
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f_root = open (self.root_img, "a+b")
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f_root.truncate (self.root_img_size)
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f_root.close ()
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if self.vm.is_template():
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self.commit_template_changes()
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def rename(self, old_name, new_name):
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super(XenStorage, self).rename(old_name, new_name)
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old_dirpath = os.path.join(os.path.dirname(self.vmdir), old_name)
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if self.rootcow_img:
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self.rootcow_img = self.rootcow_img.replace(old_dirpath,
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self.vmdir)
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def resize_private_img(self, size):
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f_private = open (self.private_img, "a+b")
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f_private.truncate (size)
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f_private.close ()
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# find loop device if any
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p = subprocess.Popen (["sudo", "losetup", "--associated", self.private_img],
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stdout=subprocess.PIPE)
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result = p.communicate()
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m = re.match(r"^(/dev/loop\d+):\s", result[0])
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if m is not None:
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loop_dev = m.group(1)
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# resize loop device
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subprocess.check_call(["sudo", "losetup", "--set-capacity", loop_dev])
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def commit_template_changes(self):
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assert self.vm.is_template()
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if not self.rootcow_img:
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return
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if os.path.exists (self.rootcow_img):
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os.rename (self.rootcow_img, self.rootcow_img + '.old')
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old_umask = os.umask(002)
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f_cow = open (self.rootcow_img, "w")
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f_root = open (self.root_img, "r")
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f_root.seek(0, os.SEEK_END)
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f_cow.truncate (f_root.tell()) # make empty sparse file of the same size as root.img
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f_cow.close ()
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f_root.close()
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os.umask(old_umask)
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def reset_volatile_storage(self, verbose = False, source_template = None):
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if source_template is None:
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source_template = self.vm.template
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if source_template is not None:
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# template-based VM with only one device-mapper layer -
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# volatile.img used as upper layer on root.img, no root-cow.img
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# intermediate layer
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if not source_template.storage.rootcow_img:
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if os.path.exists(self.volatile_img):
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if self.vm.debug:
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if os.path.getmtime(source_template.storage.root_img)\
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> os.path.getmtime(self.volatile_img):
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if verbose:
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print >>sys.stderr, "--> WARNING: template have changed, resetting root.img"
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else:
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if verbose:
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print >>sys.stderr, "--> Debug mode: not resetting root.img"
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print >>sys.stderr, "--> Debug mode: if you want to force root.img reset, either update template VM, or remove volatile.img file"
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return
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os.remove(self.volatile_img)
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f_volatile = open(self.volatile_img, "w")
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f_root = open(source_template.storage.root_img, "r")
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f_root.seek(0, os.SEEK_END)
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f_volatile.truncate(f_root.tell()) # make empty sparse file of the same size as root.img
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f_volatile.close()
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f_root.close()
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return
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super(XenStorage, self).reset_volatile_storage(
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verbose=verbose, source_template=source_template)
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def prepare_for_vm_startup(self, verbose):
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super(XenStorage, self).prepare_for_vm_startup(verbose=verbose)
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if self.drive is not None:
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(drive_type, drive_domain, drive_path) = self.drive.split(":")
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if drive_domain.lower() != "dom0":
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try:
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# FIXME: find a better way to access QubesVmCollection
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drive_vm = self.vm._collection.get_vm_by_name(drive_domain)
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# prepare for improved QubesVmCollection
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if drive_vm is None:
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raise KeyError
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if not drive_vm.is_running():
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raise QubesException(
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"VM '{}' holding '{}' isn't running".format(
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drive_domain, drive_path))
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except KeyError:
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raise QubesException(
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"VM '{}' holding '{}' does not exists".format(
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drive_domain, drive_path))
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class XenPool(Pool):
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def __init__(self, vm, dir_path):
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super(XenPool, self).__init__(vm, dir_path)
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def getStorage(self):
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""" Returns an instantiated ``XenStorage``. """
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return XenStorage(self.vm, vmdir=self.vmdir)
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