Make qubes.NotifyTools reuse logic of qubes.FeaturesRequest, then move
actual request processing to 'features-request' event handler. At the
same time implement handling 'qrexec' and 'gui' features request -
allowing to set template features when wasn't already there.
Behavior change: template is no longer allowed to change feature value
(regardless of being True or False). This means the user will always be
able to override what template have set.
With libvirt in place, this isn't enough - libvirt also keep VM
configuration in its memory and adjusting xenstore doesn't change that.
In fact changing xenstore behind it back make it even worse in some
situations.
QubesOS/qubes-issues#1426
Re-init volume config of all 'snap_on_start' volumes at template
chanage. For this, save original volume config and re-use
config_volume_from_source function introduced in previous commit.
At the same time, forbid changing template of running AppVM or any
DispVM.
QubesOS/qubes-issues#2256
vm.kernel property have type 'str'. Putting None there makes a lot of
troubles: it gets encoded as 'None' in qubes.xml and then loaded back as
'None' string, not None value. Also it isn't possible to assign None
value to str property throgh Admin API.
kernel='' is equally good to specify "no kernel from dom0".
QubesOS/qubes-issues#2622
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()
FixesQubesOS/qubes-issues#2001FixesQubesOS/qubes-issues#2666
And place them in /qubes-service/ QubesDB directory. This allows
extensions to easily store some data not exposed to VM, but also have
control what VM will see. And at the same time, it make it compatible
with existing services framework
QubesOS/qubes-issues#1637
Setting VMProperty to None VM should be encoded as '' value (according
to VMProperty._none_value). But value validation rejected this value.
QubesOS/qubes-issues#2622
