vm: avoid starting the same VM multiple times simultaneously
While libvirt handle locking itself, there is also Qubes-specific
startup part. Especially starting qrexec-daemon and waiting until
qrexec-agent connect to it. When someone will attempt to start VM the
second time (or simply assume it's already running) - qrexec will not be
connected yet and the operation will fail. Solve the problem by wrapping
the whole vm.start() function with a lock, including a check if VM is
running and waiting for qrexec.
Also, do not throw exception if VM is already running.
This way, after a call to vm.start(), VM will be started with qrexec
connected - regardless of who really started it.
Note that, it will not solve the situation when someone check if VM is
running manually, like:
if not vm.is_running():
yield from vm.start()
Such code should be changed to simply:
yield from vm.start()
Fixes QubesOS/qubes-issues#2001
Fixes QubesOS/qubes-issues#2666
This commit is contained in:
Marek Marczykowski-Górecki
parent
1f86c9253c
commit
018877a19c
@ -704,6 +704,10 @@ class QubesVM(qubes.vm.mix.net.NetVMMixin, qubes.vm.BaseVM):
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# will be initialized after loading all the properties
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#: operations which shouldn't happen simultaneously with qube startup
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# (including another startup of the same qube)
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self.startup_lock = asyncio.Lock()
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# fire hooks
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if xml is None:
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self.events_enabled = True
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@ -841,88 +845,99 @@ class QubesVM(qubes.vm.mix.net.NetVMMixin, qubes.vm.BaseVM):
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:param int mem_required: FIXME
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'''
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# Intentionally not used is_running(): eliminate also "Paused",
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# "Crashed", "Halting"
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if self.get_power_state() != 'Halted':
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raise qubes.exc.QubesVMNotHaltedError(self)
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with (yield from self.startup_lock):
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# Intentionally not used is_running(): eliminate also "Paused",
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# "Crashed", "Halting"
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if self.get_power_state() != 'Halted':
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return
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self.log.info('Starting {}'.format(self.name))
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self.log.info('Starting {}'.format(self.name))
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self.fire_event_pre('domain-pre-start', preparing_dvm=preparing_dvm,
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start_guid=start_guid, mem_required=mem_required)
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self.fire_event_pre('domain-pre-start', preparing_dvm=preparing_dvm,
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start_guid=start_guid, mem_required=mem_required)
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yield from self.storage.verify()
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yield from self.storage.verify()
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if self.netvm is not None:
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# pylint: disable = no-member
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if self.netvm.qid != 0:
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if not self.netvm.is_running():
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yield from self.netvm.start(start_guid=start_guid,
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notify_function=notify_function)
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if self.netvm is not None:
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# pylint: disable = no-member
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if self.netvm.qid != 0:
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if not self.netvm.is_running():
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yield from self.netvm.start(start_guid=start_guid,
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notify_function=notify_function)
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# TODO: lock
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qmemman_client = yield from asyncio.get_event_loop().\
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run_in_executor(None, self.request_memory, mem_required)
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qmemman_client = yield from asyncio.get_event_loop().run_in_executor(
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None, self.request_memory, mem_required)
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try:
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yield from self.storage.start()
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self._update_libvirt_domain()
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try:
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yield from self.storage.start()
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self._update_libvirt_domain()
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self.libvirt_domain.createWithFlags(
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libvirt.VIR_DOMAIN_START_PAUSED)
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finally:
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if qmemman_client:
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qmemman_client.close()
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self.libvirt_domain.createWithFlags(libvirt.VIR_DOMAIN_START_PAUSED)
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finally:
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if qmemman_client:
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qmemman_client.close()
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try:
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self.fire_event('domain-spawn',
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preparing_dvm=preparing_dvm, start_guid=start_guid)
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try:
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self.fire_event('domain-spawn',
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preparing_dvm=preparing_dvm, start_guid=start_guid)
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self.log.info('Setting Qubes DB info for the VM')
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yield from self.start_qubesdb()
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self.create_qdb_entries()
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self.log.info('Setting Qubes DB info for the VM')
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yield from self.start_qubesdb()
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self.create_qdb_entries()
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if preparing_dvm:
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self.qdb.write('/dvm', '1')
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if preparing_dvm:
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self.qdb.write('/dvm', '1')
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self.log.warning('Activating the {} VM'.format(self.name))
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self.libvirt_domain.resume()
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self.log.warning('Activating the {} VM'.format(self.name))
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self.libvirt_domain.resume()
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# close() is not really needed, because the descriptor is
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# close-on-exec anyway, the reason to postpone close() is that
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# possibly xl is not done constructing the domain after its main
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# process exits so we close() when we know the domain is up the
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# successful unpause is some indicator of it
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if qmemman_client:
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qmemman_client.close()
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qmemman_client = None
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# close() is not really needed, because the descriptor is
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# close-on-exec anyway, the reason to postpone close() is that
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# possibly xl is not done constructing the domain after its main
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# process exits so we close() when we know the domain is up the
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# successful unpause is some indicator of it
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if qmemman_client:
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qmemman_client.close()
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qmemman_client = None
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#if self._start_guid_first and start_guid and not preparing_dvm \
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# and os.path.exists('/var/run/shm.id'):
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# self.start_guid()
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# if self._start_guid_first and start_guid and not preparing_dvm \
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# and os.path.exists('/var/run/shm.id'):
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# self.start_guid()
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if not preparing_dvm:
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yield from self.start_qrexec_daemon()
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if not preparing_dvm:
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yield from self.start_qrexec_daemon()
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self.fire_event('domain-start',
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preparing_dvm=preparing_dvm, start_guid=start_guid)
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self.fire_event('domain-start',
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preparing_dvm=preparing_dvm, start_guid=start_guid)
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except: # pylint: disable=bare-except
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if self.is_running() or self.is_paused():
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# This avoids losing the exception if an exception is raised in
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# self.force_shutdown(), because the vm is not running or paused
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yield from self.kill() # pylint: disable=not-an-iterable
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raise
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finally:
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if qmemman_client:
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qmemman_client.close()
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except: # pylint: disable=bare-except
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if self.is_running() or self.is_paused():
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# This avoids losing the exception if an exception is
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# raised in self.force_shutdown(), because the vm is not
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# running or paused
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yield from self.kill() # pylint: disable=not-an-iterable
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raise
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finally:
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if qmemman_client:
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qmemman_client.close()
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return self
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@asyncio.coroutine
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def on_domain_shutdown_coro(self):
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'''Coroutine for executing cleanup after domain shutdown.
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Do not allow domain to be started again until this finishes.
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'''
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with (yield from self.startup_lock):
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yield from self.storage.stop()
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@qubes.events.handler('domain-shutdown')
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def on_domain_shutdown(self, _event, **_kwargs):
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'''Cleanup after domain shutdown'''
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asyncio.ensure_future(self.storage.stop())
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# TODO: ensure that domain haven't been started _before_ this
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# coroutine got a chance to acquire a lock
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asyncio.ensure_future(self.on_domain_shutdown_coro())
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@asyncio.coroutine
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def shutdown(self, force=False, wait=False):
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