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core: do not assume that libvirt domain is always defined

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Define it only when really needed:
 - during VM creation - to generate UUID
 - just before VM startup

As a consequence we must handle possible exception when accessing
vm.libvirt_domain. It would be a good idea to make this field private in
the future. It isn't possible for now because block_* are external for
QubesVm class.

This hopefully fixes race condition when Qubes Manager tries to access
libvirt_domain (using some QubesVm.*) at the same time as other tool is
removing the domain. Additionally if Qubes Manage would loose that race, it could
define the domain again leaving some unused libvirt domain (blocking
that domain name for future use).
This commit is contained in:
Marek Marczykowski-Górecki 2015-03-29 23:38:36 +02:00
parent e8a1e3469e
commit 075f35b873
4 changed files with 128 additions and 82 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

177
core-modules/000QubesVm.py
View File

@ -660,9 +660,14 @@ class QubesVm(object):
@property
def xid(self):
if self.libvirt_domain is None:
return -1
return self.libvirt_domain.ID()
try:
return self.libvirt_domain.ID()
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return -1
else:
raise
def get_xid(self):
# obsoleted
@ -670,34 +675,17 @@ class QubesVm(object):
def _update_libvirt_domain(self):
domain_config = self.create_config_file()
try:
self._libvirt_domain = vmm.libvirt_conn.defineXML(domain_config)
self.uuid = uuid.UUID(bytes=self._libvirt_domain.UUID())
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
# accept the fact that libvirt doesn't know anything about this
# domain...
pass
else:
raise
self._libvirt_domain = vmm.libvirt_conn.defineXML(domain_config)
self.uuid = uuid.UUID(bytes=self._libvirt_domain.UUID())
@property
def libvirt_domain(self):
if self._libvirt_domain is not None:
return self._libvirt_domain
try:
if self._libvirt_domain is None:
if self.uuid is not None:
self._libvirt_domain = vmm.libvirt_conn.lookupByUUID(self.uuid.bytes)
else:
self._libvirt_domain = vmm.libvirt_conn.lookupByName(self.name)
self.uuid = uuid.UUID(bytes=self._libvirt_domain.UUID())
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
self._update_libvirt_domain()
else:
raise
return self._libvirt_domain
def get_uuid(self):
@ -712,33 +700,41 @@ class QubesVm(object):
if dry_run:
return 666
if self.libvirt_domain is None:
return 0
if not self.libvirt_domain.isActive():
return 0
return self.libvirt_domain.info()[1]
try:
if not self.libvirt_domain.isActive():
return 0
return self.libvirt_domain.info()[1]
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return 0
else:
raise
def get_cputime(self):
if dry_run:
return 666
if self.libvirt_domain is None:
return 0
if not self.libvirt_domain.isActive():
return 0
return self.libvirt_domain.info()[4]
try:
if not self.libvirt_domain.isActive():
return 0
return self.libvirt_domain.info()[4]
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return 0
else:
raise
def get_mem_static_max(self):
if dry_run:
return 666
if self.libvirt_domain is None:
return 0
return self.libvirt_domain.maxMemory()
try:
return self.libvirt_domain.maxMemory()
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return 0
else:
raise
def get_prefmem(self):
# TODO: qmemman is still xen specific
@ -757,12 +753,17 @@ class QubesVm(object):
import random
return random.random() * 100
libvirt_domain = self.libvirt_domain
if libvirt_domain and libvirt_domain.isActive():
return libvirt_domain.getCPUStats(
libvirt.VIR_NODE_CPU_STATS_ALL_CPUS, 0)[0]['cpu_time']/10**9
else:
return 0
try:
if self.libvirt_domain.isActive():
return self.libvirt_domain.getCPUStats(
libvirt.VIR_NODE_CPU_STATS_ALL_CPUS, 0)[0]['cpu_time']/10**9
else:
return 0
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return 0
else:
raise
def get_disk_utilization_root_img(self):
return qubes.qubesutils.get_disk_usage(self.root_img)
@ -777,30 +778,32 @@ class QubesVm(object):
if dry_run:
return "NA"
libvirt_domain = self.libvirt_domain
if libvirt_domain is None:
return "NA"
if libvirt_domain.isActive():
if libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_PAUSED:
return "Paused"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_CRASHED:
return "Crashed"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_SHUTDOWN:
return "Halting"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_SHUTOFF:
return "Dying"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_PMSUSPENDED:
return "Suspended"
else:
if not self.is_fully_usable():
return "Transient"
try:
libvirt_domain = self.libvirt_domain
if libvirt_domain.isActive():
if libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_PAUSED:
return "Paused"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_CRASHED:
return "Crashed"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_SHUTDOWN:
return "Halting"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_SHUTOFF:
return "Dying"
elif libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_PMSUSPENDED:
return "Suspended"
else:
return "Running"
else:
return 'Halted'
if not self.is_fully_usable():
return "Transient"
else:
return "Running"
else:
return 'Halted'
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return "NA"
else:
raise
return "NA"
def is_guid_running(self):
xid = self.xid
@ -824,17 +827,28 @@ class QubesVm(object):
return True
def is_running(self):
if self.libvirt_domain and self.libvirt_domain.isActive():
return True
else:
return False
try:
if self.libvirt_domain.isActive():
return True
else:
return False
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return False
else:
raise
def is_paused(self):
if self.libvirt_domain and self.libvirt_domain.state()[0] == \
libvirt.VIR_DOMAIN_PAUSED:
return True
else:
return False
try:
if self.libvirt_domain.state()[0] == libvirt.VIR_DOMAIN_PAUSED:
return True
else:
return False
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
return False
else:
raise
def get_start_time(self):
if not self.is_running():
@ -1153,6 +1167,9 @@ class QubesVm(object):
else:
shutil.copy(self.label.icon_path, self.icon_path)
# Make sure that we have UUID allocated
self._update_libvirt_domain()
# fire hooks
for hook in self.hooks_create_on_disk:
hook(self, verbose, source_template=source_template)
@ -1202,6 +1219,9 @@ class QubesVm(object):
print >> sys.stderr, "--> Copying icon: {0} -> {1}".format(src_vm.icon_path, self.icon_path)
shutil.copy(src_vm.icon_path, self.icon_path)
# Make sure that we have UUID allocated
self._update_libvirt_domain()
# fire hooks
for hook in self.hooks_clone_disk_files:
hook(self, src_vm, verbose)
@ -1237,6 +1257,8 @@ class QubesVm(object):
for hook in self.hooks_remove_from_disk:
hook(self)
self.libvirt_domain.undefine()
self.storage.remove_from_disk()
def write_firewall_conf(self, conf):
@ -1771,6 +1793,7 @@ class QubesVm(object):
raise QubesException ("VM already stopped!")
self.libvirt_domain.destroy()
self.refresh()
def suspend(self):
self.log.debug('suspend()')

4
core-modules/006QubesAdminVm.py
View File

@ -75,6 +75,10 @@ class QubesAdminVm(QubesNetVm):
def get_mem_static_max(self):
return vmm.libvirt_conn.getInfo()[1]
def get_cputime(self):
# TODO: measure it somehow
return 0
def get_disk_usage(self, file_or_dir):
return 0

3
core-modules/01QubesHVm.py
View File

@ -219,6 +219,9 @@ class QubesHVm(QubesVm):
except Exception as e:
print >> sys.stderr, "WARNING: Failed to set VM icon: %s" % str(e)
# Make sure that we have UUID allocated
self._update_libvirt_domain()
# fire hooks
for hook in self.hooks_create_on_disk:
hook(self, verbose, source_template=source_template)

26
core/qubesutils.py
View File

@ -334,9 +334,18 @@ def block_check_attached(qvmc, device):
raise QubesException("You need to pass qvmc argument")
for vm in qvmc.values():
libvirt_domain = vm.libvirt_domain
if libvirt_domain:
xml = vm.libvirt_domain.XMLDesc()
try:
libvirt_domain = vm.libvirt_domain
if libvirt_domain:
xml = libvirt_domain.XMLDesc()
else:
xml = None
except libvirt.libvirtError:
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
libvirt_domain = None
else:
raise
if xml:
parsed_xml = etree.fromstring(xml)
disks = parsed_xml.xpath("//domain/devices/disk")
for disk in disks:
@ -720,8 +729,15 @@ class QubesWatch(object):
self._device_removed, None)
# TODO: device attach libvirt event
for vm in vmm.libvirt_conn.listAllDomains():
if vm.isActive():
self._register_watches(vm)
try:
if vm.isActive():
self._register_watches(vm)
except libvirt.libvirtError:
# this will happen if we loose a race with another tool,
# which can just remove the domain
if vmm.libvirt_conn.virConnGetLastError()[0] == libvirt.VIR_ERR_NO_DOMAIN:
pass
raise
# and for dom0
self._register_watches(None)