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Use separate QubesVmCollection instance when running a task in background (#986)

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QubesVmCollection is not thread safe. If for example update_table() will
be called during some long-running task (like creating or removing VM),
it will try to reload qubes.xml (so get read lock first), but the thread
already holds a lock on this file. This would result in "Lock already
taken" exception.

Fixes qubesos/qubes-issues#986
This commit is contained in:
Marek Marczykowski-Górecki 2015-05-04 01:25:55 +02:00
parent fdf0fd1870
commit f6941bd3d3
2 changed files with 50 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
qubesmanager/create_new_vm.py
View File

@ -250,39 +250,40 @@ class NewVmDlg (QDialog, Ui_NewVMDlg):
self.done(0)
def do_create_vm (self, vmclass, vmname, label, template_vm, netvm, standalone, allow_networking, thread_monitor):
@staticmethod
def do_create_vm(vmclass, vmname, label, template_vm, netvm,
standalone, allow_networking, thread_monitor):
vm = None
qc = QubesVmCollection()
qc.lock_db_for_writing()
qc.load()
try:
self.qvm_collection.lock_db_for_writing()
self.qvm_collection.load()
if not standalone:
vm = self.qvm_collection.add_new_vm(vmclass, name=vmname, template=template_vm, label=label)
vm = qc.add_new_vm(vmclass, name=vmname, template=template_vm,
label=label)
else:
vm = self.qvm_collection.add_new_vm(vmclass, name=vmname, template=None, label=label)
vm.create_on_disk(verbose=False, source_template = template_vm)
vm = qc.add_new_vm(vmclass, name=vmname, template=None,
label=label)
vm.create_on_disk(verbose=False, source_template=template_vm)
if allow_networking == False:
if not allow_networking:
vm.uses_default_netvm = False
vm.netvm = None
else:
vm.netvm = netvm
if vm.netvm == self.qvm_collection.get_default_netvm():
if vm.netvm.qid == qc.get_default_netvm().qid:
vm.uses_default_netvm = True
else:
vm.uses_default_netvm = False
self.qvm_collection.save()
qc.save()
except Exception as ex:
thread_monitor.set_error_msg (str(ex))
thread_monitor.set_error_msg(str(ex))
if vm:
vm.remove_from_disk()
self.qvm_collection.pop(vm.qid)
qc.pop(vm.qid)
finally:
self.qvm_collection.unlock_db()
qc.unlock_db()
thread_monitor.set_finished()

60
qubesmanager/main.py
View File

@ -1000,28 +1000,30 @@ class VmManagerWindow(Ui_VmManagerWindow, QMainWindow):
"ERROR: {0}".format(
thread_monitor.error_msg))
def do_remove_vm(self, vm, thread_monitor):
@staticmethod
def do_remove_vm(vm, thread_monitor):
qc = QubesVmCollection()
qc.lock_db_for_writing()
try:
self.qvm_collection.lock_db_for_writing()
self.qvm_collection.load()
vm = self.qvm_collection[vm.qid]
qc.load()
vm = qc[vm.qid]
# TODO: the following two conditions should really be checked
# by qvm_collection.pop() overload...
if vm.is_template() and \
self.qvm_collection.default_template_qid == vm.qid:
self.qvm_collection.default_template_qid = None
qc.default_template_qid == vm.qid:
qc.default_template_qid = None
if vm.is_netvm() and \
self.qvm_collection.default_netvm_qid == vm.qid:
self.qvm_collection.default_netvm_qid = None
qc.default_netvm_qid == vm.qid:
qc.default_netvm_qid = None
self.qvm_collection.pop(vm.qid)
self.qvm_collection.save()
qc.pop(vm.qid)
qc.save()
vm.remove_from_disk()
except Exception as ex:
thread_monitor.set_error_msg(str(ex))
finally:
self.qvm_collection.unlock_db()
qc.unlock_db()
thread_monitor.set_finished()
@ -1066,28 +1068,30 @@ class VmManagerWindow(Ui_VmManagerWindow, QMainWindow):
"Exception while cloning:<br>{0}".format(
thread_monitor.error_msg))
def do_clone_vm(self, vm, dst_name, thread_monitor):
@staticmethod
def do_clone_vm(vm, dst_name, thread_monitor):
dst_vm = None
qc = QubesVmCollection()
qc.lock_db_for_writing()
qc.load()
try:
self.qvm_collection.lock_db_for_writing()
self.qvm_collection.load()
src_vm = self.qvm_collection[vm.qid]
src_vm = qc[vm.qid]
dst_vm = self.qvm_collection.add_new_vm(src_vm.__class__.__name__,
name=dst_name,
template=src_vm.template,
installed_by_rpm=False)
dst_vm = qc.add_new_vm(src_vm.__class__.__name__,
name=dst_name,
template=src_vm.template,
installed_by_rpm=False)
dst_vm.clone_attrs(src_vm)
dst_vm.clone_disk_files(src_vm=src_vm, verbose=False)
self.qvm_collection.save()
self.qvm_collection.unlock_db()
qc.save()
except Exception as ex:
if dst_vm:
self.qvm_collection.pop(dst_vm.qid)
qc.pop(dst_vm.qid)
dst_vm.remove_from_disk()
self.qvm_collection.unlock_db()
thread_monitor.set_error_msg(str(ex))
finally:
qc.unlock_db()
thread_monitor.set_finished()
@pyqtSlot(name='on_action_resumevm_triggered')
@ -1126,8 +1130,8 @@ class VmManagerWindow(Ui_VmManagerWindow, QMainWindow):
self.set_error(vm.qid,
"Error starting VM: %s" % thread_monitor.error_msg)
# noinspection PyMethodMayBeStatic
def do_start_vm(self, vm, thread_monitor):
@staticmethod
def do_start_vm(vm, thread_monitor):
try:
vm.verify_files()
vm.start()
@ -1347,7 +1351,8 @@ class VmManagerWindow(Ui_VmManagerWindow, QMainWindow):
"ERROR: {0}".format(
thread_monitor.error_msg))
def do_update_vm(self, vm, thread_monitor):
@staticmethod
def do_update_vm(vm, thread_monitor):
try:
if vm.qid == 0:
subprocess.check_call(
@ -1393,7 +1398,8 @@ class VmManagerWindow(Ui_VmManagerWindow, QMainWindow):
"Exception while running command:<br>{0}".format(
thread_monitor.error_msg))
def do_run_command_in_vm(self, vm, command_to_run, thread_monitor):
@staticmethod
def do_run_command_in_vm(vm, command_to_run, thread_monitor):
try:
vm.run(command_to_run, verbose=False, autostart=True,
notify_function=lambda lvl, msg: trayIcon.showMessage(