core-admin/core/storage/__init__.py

#!/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 shutil
import subprocess
import sys

from qubes.qubes import vm_files,system_path,defaults
from qubes.qubes import QubesException
import qubes.qubesutils

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.private_img = os.path.join(self.vmdir, vm_files["private_img"])
        if self.vm.template:
            self.root_img = self.vm.template.root_img
        else:
            self.root_img = os.path.join(self.vmdir, vm_files["root_img"])
        self.volatile_img = os.path.join(self.vmdir, vm_files["volatile_img"])

        # For now compute this path still in QubesVm
        self.modules_img = modules_img
        self.modules_img_rw = modules_img_rw

    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", 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 verify_files(self):
        if not os.path.exists (self.vmdir):
            raise QubesException (
                "VM directory doesn't exist: {0}".\
                format(self.vmdir))

        if self.vm.updateable and not os.path.exists (self.root_img):
            raise QubesException (
                "VM root image file doesn't exist: {0}".\
                format(self.root_img))

        if 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:
            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 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)
        pass