Source code for qubesadmin.utils

# encoding=utf-8
#
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2010-2015  Joanna Rutkowska <joanna@invisiblethingslab.com>
# Copyright (C) 2013-2015  Marek Marczykowski-Górecki
#                              <marmarek@invisiblethingslab.com>
# Copyright (C) 2014-2015  Wojtek Porczyk <woju@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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#

"""Various utility functions."""

import fcntl
import os
import re

import qubesadmin.exc


[docs]def parse_size(size): """Parse human readable size into bytes.""" units = [ ('K', 1000), ('KB', 1000), ('M', 1000 * 1000), ('MB', 1000 * 1000), ('G', 1000 * 1000 * 1000), ('GB', 1000 * 1000 * 1000), ('Ki', 1024), ('KiB', 1024), ('Mi', 1024 * 1024), ('MiB', 1024 * 1024), ('Gi', 1024 * 1024 * 1024), ('GiB', 1024 * 1024 * 1024), ] size = size.strip().upper() if size.isdigit(): return int(size) for unit, multiplier in units: if size.endswith(unit.upper()): size = size[:-len(unit)].strip() return int(size) * multiplier raise qubesadmin.exc.QubesException("Invalid size: {0}.".format(size))
[docs]def mbytes_to_kmg(size): """Convert mbytes to human readable format.""" if size > 1024: return "%d GiB" % (size / 1024) return "%d MiB" % size
[docs]def kbytes_to_kmg(size): """Convert kbytes to human readable format.""" if size > 1024: return mbytes_to_kmg(size / 1024) return "%d KiB" % size
[docs]def bytes_to_kmg(size): """Convert bytes to human readable format.""" if size > 1024: return kbytes_to_kmg(size / 1024) return "%d B" % size
[docs]def size_to_human(size): """Humane readable size, with 1/10 precision""" if size < 1024: return str(size) if size < 1024 * 1024: return str(round(size / 1024.0, 1)) + ' KiB' if size < 1024 * 1024 * 1024: return str(round(size / (1024.0 * 1024), 1)) + ' MiB' return str(round(size / (1024.0 * 1024 * 1024), 1)) + ' GiB'
[docs]def get_entry_point_one(group, name): """Get a single entry point of given type, raise TypeError when there are multiple. """ import pkg_resources epoints = tuple(pkg_resources.iter_entry_points(group, name)) if not epoints: raise KeyError(name) if len(epoints) > 1: raise TypeError('more than 1 implementation of {!r} found: {}'.format( name, ', '.join('{}.{}'.format(ep.module_name, '.'.join(ep.attrs)) for ep in epoints))) return epoints[0].load()
UPDATES_DEFAULT_VM_DISABLE_FLAG = \ '/var/lib/qubes/updates/vm-default-disable-updates'
[docs]def updates_vms_status(qvm_collection): """Check whether all VMs have the same check-updates value; if yes, return it; otherwise, return None """ # default value: status = not os.path.exists(UPDATES_DEFAULT_VM_DISABLE_FLAG) # check if all the VMs uses the default value for vm in qvm_collection.domains: if vm.qid == 0: continue if vm.features.get('check-updates', True) != status: # "mixed" return None return status
[docs]def vm_dependencies(app, reference_vm): """Helper function that returns a list of all the places a given VM is used in. Output is a list of tuples (property_holder, property_name), with None as property_holder for global properties """ result = [] global_properties = ['default_dispvm', 'default_netvm', 'default_guivm', 'default_audiovm', 'default_template', 'clockvm', 'updatevm', 'management_dispvm'] for prop in global_properties: if reference_vm == getattr(app, prop, None): result.append((None, prop)) vm_properties = ['template', 'netvm', 'guivm', 'audiovm', 'default_dispvm', 'management_dispvm'] for vm in app.domains: if vm == reference_vm: continue for prop in vm_properties: if reference_vm == getattr(vm, prop, None) and \ not vm.property_is_default(prop): result.append((vm, prop)) return result
[docs]def encode_for_vmexec(args): """ Encode an argument list for qubes.VMExec call. """ def encode(part): if part.group(0) == b'-': return b'--' return '-{:02X}'.format(ord(part.group(0))).encode('ascii') parts = [] for arg in args: part = re.sub(br'[^a-zA-Z0-9_.]', encode, arg.encode('utf-8')) parts.append(part) return b'+'.join(parts).decode('ascii')
[docs]class LockFile(object): """Simple locking context manager. It opens a file with an advisory lock taken (fcntl.lockf)""" def __init__(self, path, nonblock=False): """Open the file. Call *acquire* or enter the context to lock the file""" self.file = open(path, "w") self.nonblock = nonblock def __enter__(self, *args, **kwargs): self.acquire() return self
[docs] def acquire(self): """Lock the opened file""" fcntl.lockf(self.file, fcntl.LOCK_EX | (fcntl.LOCK_NB if self.nonblock else 0))
def __exit__(self, exc_type=None, exc_value=None, traceback=None): self.release()
[docs] def release(self): """Unlock the file and close the file object""" fcntl.lockf(self.file, fcntl.LOCK_UN) self.file.close()