libvirt/include
Eric Blake 2629520342 qemu: new API for tracking arbitrary monitor events
Several times in the past, qemu has implemented a new event,
but libvirt has not yet caught up to reporting that event to
the user applications.  While it is possible to track libvirt
logs to see that an unknown event was received and ignored,
it would be nicer to copy what 'virsh qemu-monitor-command'
does, and expose this information to the end developer as
one of our unsupported qemu-specific commands.

If you find yourself needing to use this API for more than
just development purposes, please ask on the libvirt list
for a supported counterpart event to be added in libvirt.so.

While the supported virConnectDomainEventRegisterAny() API
takes an id which determines the signature of the callback,
this version takes a string filter and always uses the same
signature.  Furthermore, I chose to expose this as a new API
instead of trying to add a new eventID at the top level, in
part because the generic option lacks event name filtering,
and in part because the normal domain event namespace should
not be polluted by a qemu-only event.  I also added a flags
argument; unused for now, but we might decide to use it to
allow a user to request event names by glob or regex instead
of literal match.

This API intentionally requires full write access (while
normal event registration is allowed on read-only clients);
this is in part due to the fact that it should only be used
by debugging situations, and in part because the design of
per-event filtering in later patches ended up allowing for
duplicate registrations that could potentially be abused to
exhaust server memory - requiring write privileges means
that such abuse will not serve as a denial of service attack
against users with higher privileges.

* include/libvirt/libvirt-qemu.h
(virConnectDomainQemuMonitorEventCallback)
(virConnectDomainQemuMonitorEventRegister)
(virConnectDomainQemuMonitorEventDeregister): New prototypes.
* src/libvirt-qemu.c (virConnectDomainQemuMonitorEventRegister)
(virConnectDomainQemuMonitorEventDeregister): New functions.
* src/libvirt_qemu.syms (LIBVIRT_QEMU_1.2.1): Export them.
* src/driver.h (virDrvConnectDomainQemuMonitorEventRegister)
(virDrvConnectDomainQemuMonitorEventDeregister): New callbacks.

Signed-off-by: Eric Blake <eblake@redhat.com>
2014-03-20 11:25:37 -06:00
..
libvirt qemu: new API for tracking arbitrary monitor events 2014-03-20 11:25:37 -06:00
Makefile.am maint: use LGPL correctly 2013-05-20 14:03:48 -06:00