core-admin-client/qubesadmin/tools/qvm_start.py
Marta Marczykowska-Górecka fa396a6da9
Better error reporting in qvm_start
When user provides incorrect image name/path, the tool
will now inform what's wrong.
2020-10-07 20:44:32 +02:00

216 lines
7.6 KiB
Python

# -*- encoding: utf8 -*-
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2017 Marek Marczykowski-Górecki
# <marmarek@invisiblethingslab.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with this program; if not, see <http://www.gnu.org/licenses/>.
'''qvm-start - start a domain'''
import argparse
import string
import sys
import subprocess
import time
import qubesadmin.devices
import qubesadmin.exc
import qubesadmin.tools
class DriveAction(argparse.Action):
'''Action for argument parser that stores drive image path.'''
# pylint: disable=redefined-builtin,too-few-public-methods
def __init__(self,
option_strings,
dest='drive',
prefix='cdrom:',
metavar='IMAGE',
required=False,
help='Attach drive'):
super().__init__(option_strings, dest,
metavar=metavar, help=help)
self.prefix = prefix
def __call__(self, parser, namespace, values, option_string=None):
# pylint: disable=redefined-outer-name
setattr(namespace, self.dest, self.prefix + values)
parser = qubesadmin.tools.QubesArgumentParser(
description='start a domain', vmname_nargs='+')
parser.add_argument('--skip-if-running',
action='store_true', default=False,
help='Do not fail if the qube is already runnning')
parser_drive = parser.add_mutually_exclusive_group()
parser_drive.add_argument('--drive', metavar='DRIVE',
help='temporarily attach specified drive as CD/DVD or hard disk (can be'
' specified with prefix "hd:" or "cdrom:", default is cdrom)')
parser_drive.add_argument('--hddisk',
action=DriveAction, dest='drive', prefix='hd:',
help='temporarily attach specified drive as hard disk')
parser_drive.add_argument('--cdrom', metavar='IMAGE',
action=DriveAction, dest='drive', prefix='cdrom:',
help='temporarily attach specified drive as CD/DVD')
parser_drive.add_argument('--install-windows-tools',
action='store_const', dest='drive', default=False,
const='cdrom:dom0:/usr/lib/qubes/qubes-windows-tools.iso',
help='temporarily attach Windows tools CDROM to the domain')
def get_drive_assignment(app, drive_str):
''' Prepare :py:class:`qubesadmin.devices.DeviceAssignment` object for a
given drive.
If running in dom0, it will also take care about creating appropriate
loop device (if necessary). Otherwise, only existing block devices are
supported.
:param app: Qubes() instance
:param drive_str: drive argument
:return: DeviceAssignment matching *drive_str*
'''
devtype = 'cdrom'
if drive_str.startswith('cdrom:'):
devtype = 'cdrom'
drive_str = drive_str[len('cdrom:'):]
elif drive_str.startswith('hd:'):
devtype = 'disk'
drive_str = drive_str[len('hd:'):]
try:
backend_domain_name, ident = drive_str.split(':', 1)
except ValueError:
raise ValueError("Incorrect image name: image must be in the format "
"of VMNAME:full_path, for example "
"dom0:/home/user/test.iso")
try:
backend_domain = app.domains[backend_domain_name]
except KeyError:
raise qubesadmin.exc.QubesVMNotFoundError(
'No such VM: %s', backend_domain_name)
if ident.startswith('/'):
# it is a path - if we're running in dom0, try to call losetup to
# export the device, otherwise reject
if app.qubesd_connection_type == 'qrexec':
raise qubesadmin.exc.QubesException(
'Existing block device identifier needed when running from '
'outside of dom0 (see qvm-block)')
try:
if backend_domain.klass == 'AdminVM':
loop_name = subprocess.check_output(
['sudo', 'losetup', '-f', '--show', ident])
loop_name = loop_name.strip()
else:
untrusted_loop_name, _ = backend_domain.run_with_args(
'losetup', '-f', '--show', ident,
user='root')
untrusted_loop_name = untrusted_loop_name.strip()
allowed_chars = string.ascii_lowercase + string.digits + '/'
allowed_chars = allowed_chars.encode('ascii')
if not all(c in allowed_chars for c in untrusted_loop_name):
raise qubesadmin.exc.QubesException(
'Invalid loop device name received from {}'.format(
backend_domain.name))
loop_name = untrusted_loop_name
del untrusted_loop_name
except subprocess.CalledProcessError:
raise qubesadmin.exc.QubesException(
'Failed to setup loop device for %s', ident)
assert loop_name.startswith(b'/dev/loop')
ident = loop_name.decode().split('/')[2]
# wait for device to appear
# FIXME: convert this to waiting for event
timeout = 10
while isinstance(backend_domain.devices['block'][ident],
qubesadmin.devices.UnknownDevice):
if timeout == 0:
raise qubesadmin.exc.QubesException(
'Timeout waiting for {}:{} device to appear'.format(
backend_domain.name, ident))
timeout -= 1
time.sleep(1)
options = {
'devtype': devtype,
'read-only': devtype == 'cdrom'
}
assignment = qubesadmin.devices.DeviceAssignment(
backend_domain,
ident,
options=options,
persistent=True)
return assignment
def main(args=None, app=None):
'''Main routine of :program:`qvm-start`.
:param list args: Optional arguments to override those delivered from \
command line.
'''
args = parser.parse_args(args, app=app)
exit_code = 0
for domain in args.domains:
if domain.is_running():
if args.skip_if_running:
continue
exit_code = 1
parser.print_error(
'domain {} is already running'.format(domain.name))
return exit_code
drive_assignment = None
try:
if args.drive:
drive_assignment = get_drive_assignment(args.app, args.drive)
try:
domain.devices['block'].attach(drive_assignment)
except:
drive_assignment = None
raise
domain.start()
if drive_assignment:
# don't reconnect this device after VM reboot
domain.devices['block'].update_persistent(
drive_assignment.device, False)
except (IOError, OSError, qubesadmin.exc.QubesException,
ValueError) as e:
if drive_assignment:
try:
domain.devices['block'].detach(drive_assignment)
except qubesadmin.exc.QubesException:
pass
exit_code = 1
parser.print_error(str(e))
return exit_code
if __name__ == '__main__':
sys.exit(main())