In order to mirror a server with per-object filtering, the client
needs to track which server callbackID is servicing the client
callback.  This patch introduces the notion of a serverID, as
well as the plumbing to use it for network events, although the
actual complexity of using per-object filtering in the remote
driver is deferred to a later patch.

* src/conf/object_event.h (virObjectEventStateEventID): Add parameter.
(virObjectEventStateQueueRemote, virObjectEventStateSetRemote):
New prototypes.
(virObjectEventStateRegisterID): Move...
* src/conf/object_event_private.h: ...here, and add parameter.
(_virObjectEvent): Add field.
* src/conf/network_event.h (virNetworkEventStateRegisterClient): New
prototype.
* src/conf/object_event.c (_virObjectEventCallback): Add field.
(virObjectEventStateSetRemote): New function.
(virObjectEventStateQueue): Make wrapper around...
(virObjectEventStateQueueRemote): New function.
(virObjectEventCallbackListCount): Tweak return count when remote
id matching is used.
(virObjectEventCallbackLookup, virObjectEventStateRegisterID):
Tweak registration when remote id matching will be used.
(virObjectEventNew): Default to no remote id.
(virObjectEventCallbackListAddID): Likewise, but set remote id
when one is available.
(virObjectEventCallbackListRemoveID)
(virObjectEventCallbackListMarkDeleteID): Adjust return value when
remote id was set.
(virObjectEventStateEventID): Query existing id.
(virObjectEventDispatchMatchCallback): Require matching event id.
(virObjectEventStateCallbackID): Adjust caller.
* src/conf/network_event.c (virNetworkEventStateRegisterClient): New
function.
(virNetworkEventStateRegisterID): Update caller.
* src/conf/domain_event.c (virDomainEventStateRegister)
(virDomainEventStateRegisterID): Update callers.
* src/remote/remote_driver.c
(remoteConnectNetworkEventRegisterAny)
(remoteConnectNetworkEventDeregisterAny)
(remoteConnectDomainEventDeregisterAny): Likewise.
(remoteEventQueue): Hoist earlier to avoid forward declaration,
and add parameter.  Adjust all callers.
* src/libvirt_private.syms (conf/object_event.h): Drop function.
Signed-off-by: NEric Blake <eblake@redhat.com>

If a user registers for a domain event filtered to a particular
domain, but the persistent domain is offline at the time, then
the code silently failed to set up the filter.  As a result,
the event fires for all domains, rather than being filtered.
Network events were immune, since they always passed an id
0 argument.

The key to this patch is realizing that
virObjectEventDispatchMatchCallback() only cared about uuid;
so refusing to create a meta for a negative id is pointless,
and in fact, malloc'ing meta at all was overkill; instead,
just directly store a uuid and a flag of whether to filter.

Note that virObjectEventPtr still needs all fields of meta,
because this is how we reconstruct a virDomainPtr inside the
dispatch handler before calling the end user's callback
pointer with the correct object, even though only the uuid
portion of meta is used in deciding whether a callback
matches the given event.  So while uuid is optional for
callbacks, it is mandatory for events.

The change to testDomainCreateXMLMixed is merely on the setup
scenario (as you can't register for a domain unless it is either
running or persistent).  I actually first wrote that test for
this patch, then rebased it to also cover a prior patch (commit
4221d64f), but had to adjust it for that patch to use Create
instead of Define for setting up the domain long enough to
register the event in order to work around this bug.  But while
the setup is changed, the main body of the test is still about
whether creation events fire as expected.

* src/conf/object_event_private.h (_virObjectEventCallback):
Replace meta with uuid and flag.
(virObjectEventCallbackListAddID): Update signature.
* src/conf/object_event.h (virObjectEventStateRegisterID):
Likewise.
* src/conf/object_event_private.h (virObjectEventNew): Document
use of name and uuid in events.
* src/conf/object_event.c (virObjectEventCallbackListAddID): Drop
arguments that don't affect filtering.
(virObjectEventCallbackListRemoveID)
(virObjectEventDispatchMatchCallback)
(virObjectEventStateRegisterID): Update clients.
* src/conf/domain_event.c (virDomainEventCallbackListAdd)
(virDomainEventStateRegisterID): Likewise.
* src/conf/network_event.c (virNetworkEventStateRegisterID):
Likewise.
* tests/objecteventtest.c (testDomainCreateXMLMixed): Enhance test.
Signed-off-by: NEric Blake <eblake@redhat.com>

Right now, the older virConnectDomainEventRegister (takes a
function pointer, returns 0 on success) and the newer
virConnectDomainEventRegisterID (takes an eventID, returns a
callbackID) share the underlying implementation (the older
API ends up consuming a callbackID for eventID 0 under the
hood).  We implemented that by a lot of copy and pasted
code between object_event.c and domain_event.c, according to
whether we are dealing with a function pointer or an eventID.
However, our copy and paste is not symmetric.  Consider this
sequence:

id1 = virConnectDomainEventRegisterAny(conn, dom,
   VIR_DOMAIN_EVENT_ID_LIFECYCLE,
   VIR_DOMAIN_EVENT_CALLBACK(callback), NULL, NULL);
virConnectDomainEventRegister(conn, callback, NULL, NULL);
virConnectDomainEventDeregister(conn, callback);
virConnectDomainEventDeregsiterAny(conn, id1);

the first three calls would succeed, but the third call ended
up nuking the id1 callbackID (the per-domain new-style handler),
then the fourth call failed with an error about an unknown
callbackID, leaving us with the global handler (old-style) still
live and receiving events.  It required another old-style
deregister to clean up the mess.  Root cause was that
virDomainEventCallbackList{Remove,MarkDelete} were only
checking for function pointer match, rather than also checking
for whether the registration was global.

Rather than playing with the guts of object_event ourselves
in domain_event, it is nicer to add a mapping function for the
internal callback id, then share common code for event removal.
For now, the function-to-id mapping is used only internally;
I thought about whether a new public API to let a user learn
the callback would be useful, but decided exposing this to the
user is probably a disservice, since we already publicly
document that they should avoid the old style, and since this
patch already demonstrates that older libvirt versions have
weird behavior when mixing old and new styles.

And like all good bug fix patches, I enhanced the testsuite,
validating that the changes in tests/ expose the failure
without the rest of the patch.

* src/conf/object_event.c (virObjectEventCallbackLookup)
(virObjectEventStateCallbackID): New functions.
(virObjectEventCallbackLookup): Use helper function.
* src/conf/object_event_private.h (virObjectEventStateCallbackID):
Declare new function.
* src/conf/domain_event.c (virDomainEventStateRegister)
(virDomainEventStateDeregister): Let common code handle the
complexity.
(virDomainEventCallbackListRemove)
(virDomainEventCallbackListMarkDelete)
(virDomainEventCallbackListAdd): Drop unused functions.
* tests/objecteventtest.c (testDomainCreateXMLMixed): New test.
Signed-off-by: NEric Blake <eblake@redhat.com>

No need to use an int that only ever stores 0 and 1.

* src/conf/object_event_private.h (_virObjectEventCallback):
Change deleted to bool.
* src/conf/object_event.c (virObjectEventDispatchMatchCallback):
Switch return type to bool.
(virObjectEventCallbackListMarkDeleteID): Update client.
* src/conf/domain_event.c (virDomainEventCallbackListMarkDelete):
Likewise.

Any file with access to object_event_private.h also has access to
the internals of virObjectEvent, without needing an accessor
function.  Not to mention the accessor function was doing type
checks that would always succeed.

* src/conf/object_event_private.h (virObjectEventGetEventID): Drop.
* src/conf/object_event.c (virObjectEventGetEventID): Drop.
(virObjectEventDispatchMatchCallback): Simplify caller.
* src/conf/domain_event.c (virDomainEventDispatchDefaultFunc):
Likewise.
Signed-off-by: NEric Blake <eblake@redhat.com>

While working on events, I found a number of minor issues; I'm
hoisting these to the front rather than doing it piecemeal in
the patches where I first noticed bad or missing documentation.

* src/conf/object_event.c: Fix grammar, document all parameters
of public functions, wrap some long lines.
* src/conf/object_event.h: Likewise.
* src/conf/network_event.c: Likewise.
* src/conf/domain_event.c: Likewise (except for the large number
of event creation functions).
* src/libvirt_private.cyms (conf/object_event.h): Split...
(conf/network_event.h): ...to account for new file.
Signed-off-by: NEric Blake <eblake@redhat.com>

The event namespace concept is mostly redundant information.
With the re-written dispatcher, the namespace is only used
for equality comparisons between event IDs. This can be solved
by just comparing virClassPtr instances instead.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Instead of having the object event code have to know about each
type of event and their dispatch functions, associate a dispatch
function with the object instance. The dispatch code can thus be
significantly simplified.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Each unique event ID will thus be composed by 1 byte for the namespace
and 1 byte for a namespace-specific ID. The namespace for domain event
needs to be 0 for compatibility reasons.

The virDomainEvent class is kept as it indicates what meta informations
are valid for the children classes. This may be useful in the future.

RIP virDomainEvent union. All data are now stored in each
virObjectEvent subclass.

This change may be confusing at first, but provides a much more
consistent naming scheme for the virObjectEvent children construction
functions.

This aims at providing some consistency with other domain events

Added a parent class virObjectEvent for future event types

Keep virDomainEventStateRegisterID as a convenience wrapper around
this new function.

Keep the legacy Domain lifecycle event functions as is.

Leave virDomainEventRegister and its Deregister brother as these are
legacy functions only for domain lifecycle events.

The event queue will be generalized to hold events related
to any object type.

The metadata struct will hold the unique identifiers for
any type of object, though not all fields will be used
for all types.

The event callbacks will be generalized to handle events
for any object type.

The @list->callbacks is an array that is inflated whenever a new event
is added, e.g. via virDomainEventCallbackListAddID(). However, when we
are freeing the array, we free the items within it but forgot to
actually free it.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Commit id '4421e257' strdup'd devAlias, but didn't free

Running qemuhotplugtest under valgrind resulted in the following:

==7375== 9 bytes in 1 blocks are definitely lost in loss record 11 of 70
==7375==    at 0x4A0887C: malloc (vg_replace_malloc.c:270)
==7375==    by 0x37C1085D71: strdup (strdup.c:42)
==7375==    by 0x4CBBD5F: virStrdup (virstring.c:554)
==7375==    by 0x4CFF9CB: virDomainEventDeviceRemovedNew (domain_event.c:1174)
==7375==    by 0x427791: qemuDomainRemoveChrDevice (qemu_hotplug.c:2508)
==7375==    by 0x42C65D: qemuDomainDetachChrDevice (qemu_hotplug.c:3357)
==7375==    by 0x41C94F: testQemuHotplug (qemuhotplugtest.c:115)
==7375==    by 0x41D817: virtTestRun (testutils.c:168)
==7375==    by 0x41C400: mymain (qemuhotplugtest.c:322)
==7375==    by 0x41DF3A: virtTestMain (testutils.c:764)
==7375==    by 0x37C1021A04: (below main) (libc-start.c:225)

Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>