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libvirt/src/conf/object_event.c
John Ferlan 2065499b60 events: Avoid double free possibility on remote call failure 
If a remote call fails during event registration (more than likely from
a network failure or remote libvirtd restart timed just right), then when
calling the virObjectEventStateDeregisterID we don't want to call the
registered @freecb function because that breaks our contract that we
would only call it after succesfully returning.  If the @freecb routine
were called, it could result in a double free from properly coded
applications that free their opaque data on failure to register, as seen
in the following details:

    Program terminated with signal 6, Aborted.
    #0  0x00007fc45cba15d7 in raise
    #1  0x00007fc45cba2cc8 in abort
    #2  0x00007fc45cbe12f7 in __libc_message
    #3  0x00007fc45cbe86d3 in _int_free
    #4  0x00007fc45d8d292c in PyDict_Fini
    #5  0x00007fc45d94f46a in Py_Finalize
    #6  0x00007fc45d960735 in Py_Main
    #7  0x00007fc45cb8daf5 in __libc_start_main
    #8  0x0000000000400721 in _start

The double dereference of 'pyobj_cbData' is triggered in the following way:

    (1) libvirt_virConnectDomainEventRegisterAny is invoked.
    (2) the event is successfully added to the event callback list
        (virDomainEventStateRegisterClient in
        remoteConnectDomainEventRegisterAny returns 1 which means ok).
    (3) when function remoteConnectDomainEventRegisterAny is hit,
        network connection disconnected coincidently (or libvirtd is
        restarted) in the context of function 'call' then the connection
        is lost and the function 'call' failed, the branch
        virObjectEventStateDeregisterID is therefore taken.
    (4) 'pyobj_conn' is dereferenced the 1st time in
        libvirt_virConnectDomainEventFreeFunc.
    (5) 'pyobj_cbData' (refered to pyobj_conn) is dereferenced the
         2nd time in libvirt_virConnectDomainEventRegisterAny.
    (6) the double free error is triggered.

Resolve this by adding a @doFreeCb boolean in order to avoid calling the
freeCb in virObjectEventStateDeregisterID for any remote call failure in
a remoteConnect*EventRegister* API. For remoteConnect*EventDeregister* calls,
the passed value would be true indicating they should run the freecb if it
exists; whereas, it's false for the remote call failure path.

Patch based on the investigation and initial patch posted by
fangying <fangying1@huawei.com>.
2017-06-25 08:16:04 -04:00

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/*
* object_event.c: object event queue processing helpers
*
* Copyright (C) 2010-2014 Red Hat, Inc.
* Copyright (C) 2008 VirtualIron
* Copyright (C) 2013 SUSE LINUX Products GmbH, Nuernberg, Germany.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*
* Author: Ben Guthro
*/
#include <config.h>
#include "domain_event.h"
#include "network_event.h"
#include "object_event.h"
#include "object_event_private.h"
#include "virlog.h"
#include "datatypes.h"
#include "viralloc.h"
#include "virerror.h"
#include "virobject.h"
#include "virstring.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("conf.object_event");
struct _virObjectEventCallback {
int callbackID;
virClassPtr klass;
int eventID;
virConnectPtr conn;
int remoteID;
bool key_filter;
char *key;
virObjectEventCallbackFilter filter;
void *filter_opaque;
virConnectObjectEventGenericCallback cb;
void *opaque;
virFreeCallback freecb;
bool deleted;
bool legacy; /* true if end user does not know callbackID */
};
typedef struct _virObjectEventCallback virObjectEventCallback;
typedef virObjectEventCallback *virObjectEventCallbackPtr;
struct _virObjectEventCallbackList {
unsigned int nextID;
size_t count;
virObjectEventCallbackPtr *callbacks;
};
struct _virObjectEventQueue {
size_t count;
virObjectEventPtr *events;
};
typedef struct _virObjectEventQueue virObjectEventQueue;
typedef virObjectEventQueue *virObjectEventQueuePtr;
struct _virObjectEventState {
virObjectLockable parent;
/* The list of domain event callbacks */
virObjectEventCallbackListPtr callbacks;
/* The queue of object events */
virObjectEventQueuePtr queue;
/* Timer for flushing events queue */
int timer;
/* Flag if we're in process of dispatching */
bool isDispatching;
};
static virClassPtr virObjectEventClass;
static virClassPtr virObjectEventStateClass;
static void virObjectEventDispose(void *obj);
static void virObjectEventStateDispose(void *obj);
static int
virObjectEventOnceInit(void)
{
if (!(virObjectEventStateClass =
virClassNew(virClassForObjectLockable(),
"virObjectEventState",
sizeof(virObjectEventState),
virObjectEventStateDispose)))
return -1;
if (!(virObjectEventClass =
virClassNew(virClassForObject(),
"virObjectEvent",
sizeof(virObjectEvent),
virObjectEventDispose)))
return -1;
return 0;
}
VIR_ONCE_GLOBAL_INIT(virObjectEvent)
/**
* virClassForObjectEvent:
*
* Return the class object to be used as a parent when creating an
* event subclass.
*/
virClassPtr
virClassForObjectEvent(void)
{
if (virObjectEventInitialize() < 0)
return NULL;
return virObjectEventClass;
}
static void
virObjectEventDispose(void *obj)
{
virObjectEventPtr event = obj;
VIR_DEBUG("obj=%p", event);
VIR_FREE(event->meta.name);
VIR_FREE(event->meta.key);
}
/**
* virObjectEventCallbackFree:
* @list: event callback to free
*
* Free the memory in the domain event callback
*/
static void
virObjectEventCallbackFree(virObjectEventCallbackPtr cb)
{
if (!cb)
return;
virObjectUnref(cb->conn);
VIR_FREE(cb->key);
VIR_FREE(cb);
}
/**
* virObjectEventCallbackListFree:
* @list: event callback list head
*
* Free the memory in the domain event callback list
*/
static void
virObjectEventCallbackListFree(virObjectEventCallbackListPtr list)
{
size_t i;
if (!list)
return;
for (i = 0; i < list->count; i++) {
virFreeCallback freecb = list->callbacks[i]->freecb;
if (freecb)
(*freecb)(list->callbacks[i]->opaque);
VIR_FREE(list->callbacks[i]);
}
VIR_FREE(list->callbacks);
VIR_FREE(list);
}
/**
* virObjectEventCallbackListCount:
* @conn: pointer to the connection
* @cbList: the list
* @klass: the base event class
* @eventID: the event ID
* @key: optional key of per-object filtering
* @serverFilter: true if server supports object filtering
*
* Internal function to count how many callbacks remain registered for
* the given @eventID and @key; knowing this allows the client side
* of the remote driver know when it must send an RPC to adjust the
* callbacks on the server. When @serverFilter is false, this function
* returns a count that includes both global and per-object callbacks,
* since the remote side will use a single global event to feed both.
* When true, the count is limited to the callbacks with the same
* @key, and where a remoteID has already been set on the callback
* with virObjectEventStateSetRemote(). Note that this function
* intentionally ignores the legacy field, since RPC calls use only a
* single callback on the server to manage both legacy and modern
* global domain lifecycle events.
*/
static int
virObjectEventCallbackListCount(virConnectPtr conn,
virObjectEventCallbackListPtr cbList,
virClassPtr klass,
int eventID,
const char *key,
bool serverFilter)
{
size_t i;
int ret = 0;
for (i = 0; i < cbList->count; i++) {
virObjectEventCallbackPtr cb = cbList->callbacks[i];
if (cb->filter)
continue;
if (cb->klass == klass &&
cb->eventID == eventID &&
cb->conn == conn &&
!cb->deleted &&
(!serverFilter ||
(cb->remoteID >= 0 &&
((key && cb->key_filter && STREQ(cb->key, key)) ||
(!key && !cb->key_filter)))))
ret++;
}
return ret;
}
/**
* virObjectEventCallbackListRemoveID:
* @conn: pointer to the connection
* @cbList: the list
* @callback: the callback to remove
* @doFreeCb: Inhibit calling the freecb
*
* Internal function to remove a callback from a virObjectEventCallbackListPtr
*/
static int
virObjectEventCallbackListRemoveID(virConnectPtr conn,
virObjectEventCallbackListPtr cbList,
int callbackID,
bool doFreeCb)
{
size_t i;
for (i = 0; i < cbList->count; i++) {
virObjectEventCallbackPtr cb = cbList->callbacks[i];
if (cb->callbackID == callbackID && cb->conn == conn) {
int ret;
ret = cb->filter ? 0 :
(virObjectEventCallbackListCount(conn, cbList, cb->klass,
cb->eventID,
cb->key_filter ? cb->key : NULL,
cb->remoteID >= 0) - 1);
/* @doFreeCb inhibits calling @freecb from error paths in
* register functions to ensure the caller of a failed register
* function won't end up with a double free error */
if (doFreeCb && cb->freecb)
(*cb->freecb)(cb->opaque);
virObjectEventCallbackFree(cb);
VIR_DELETE_ELEMENT(cbList->callbacks, i, cbList->count);
return ret;
}
}
virReportError(VIR_ERR_INVALID_ARG,
_("could not find event callback %d for deletion"),
callbackID);
return -1;
}
static int
virObjectEventCallbackListMarkDeleteID(virConnectPtr conn,
virObjectEventCallbackListPtr cbList,
int callbackID)
{
size_t i;
for (i = 0; i < cbList->count; i++) {
virObjectEventCallbackPtr cb = cbList->callbacks[i];
if (cb->callbackID == callbackID && cb->conn == conn) {
cb->deleted = true;
return cb->filter ? 0 :
virObjectEventCallbackListCount(conn, cbList, cb->klass,
cb->eventID,
cb->key_filter ? cb->key : NULL,
cb->remoteID >= 0);
}
}
virReportError(VIR_ERR_INVALID_ARG,
_("could not find event callback %d for deletion"),
callbackID);
return -1;
}
static int
virObjectEventCallbackListPurgeMarked(virObjectEventCallbackListPtr cbList)
{
size_t n;
for (n = 0; n < cbList->count; n++) {
if (cbList->callbacks[n]->deleted) {
virFreeCallback freecb = cbList->callbacks[n]->freecb;
if (freecb)
(*freecb)(cbList->callbacks[n]->opaque);
virObjectEventCallbackFree(cbList->callbacks[n]);
VIR_DELETE_ELEMENT(cbList->callbacks, n, cbList->count);
n--;
}
}
return 0;
}
/**
* virObjectEventCallbackLookup:
* @conn: pointer to the connection
* @cbList: the list
* @key: the key of the object to filter on
* @klass: the base event class
* @eventID: the event ID
* @callback: the callback to locate
* @legacy: true if callback is tracked by function instead of callbackID
* @remoteID: optionally return a known remoteID
*
* Internal function to determine if @callback already has a
* callbackID in @cbList for the given @conn and other filters. If
* @remoteID is non-NULL, and another callback exists that can be
* serviced by the same remote event, then set it to that remote ID.
*
* Return the id if found, or -1 with no error issued if not present.
*/
static int ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
virObjectEventCallbackLookup(virConnectPtr conn,
virObjectEventCallbackListPtr cbList,
const char *key,
virClassPtr klass,
int eventID,
virConnectObjectEventGenericCallback callback,
bool legacy,
int *remoteID)
{
size_t i;
if (remoteID)
*remoteID = -1;
for (i = 0; i < cbList->count; i++) {
virObjectEventCallbackPtr cb = cbList->callbacks[i];
if (cb->deleted)
continue;
if (cb->klass == klass &&
cb->eventID == eventID &&
cb->conn == conn &&
((key && cb->key_filter && STREQ(cb->key, key)) ||
(!key && !cb->key_filter))) {
if (remoteID)
*remoteID = cb->remoteID;
if (cb->legacy == legacy &&
cb->cb == callback)
return cb->callbackID;
}
}
return -1;
}
/**
* virObjectEventCallbackListAddID:
* @conn: pointer to the connection
* @cbList: the list
* @key: the optional key of the object to filter on
* @filter: optional last-ditch filter callback
* @filter_opaque: opaque data to pass to @filter
* @klass: the base event class
* @eventID: the event ID
* @callback: the callback to add
* @opaque: opaque data to pass to @callback
* @freecb: callback to free @opaque
* @legacy: true if callback is tracked by function instead of callbackID
* @callbackID: filled with callback ID
* @serverFilter: true if server supports object filtering
*
* Internal function to add a callback from a virObjectEventCallbackListPtr
*/
static int
virObjectEventCallbackListAddID(virConnectPtr conn,
virObjectEventCallbackListPtr cbList,
const char *key,
virObjectEventCallbackFilter filter,
void *filter_opaque,
virClassPtr klass,
int eventID,
virConnectObjectEventGenericCallback callback,
void *opaque,
virFreeCallback freecb,
bool legacy,
int *callbackID,
bool serverFilter)
{
virObjectEventCallbackPtr cb;
int ret = -1;
int remoteID = -1;
VIR_DEBUG("conn=%p cblist=%p key=%p filter=%p filter_opaque=%p "
"klass=%p eventID=%d callback=%p opaque=%p "
"legacy=%d callbackID=%p serverFilter=%d",
conn, cbList, key, filter, filter_opaque, klass, eventID,
callback, opaque, legacy, callbackID, serverFilter);
/* Check incoming */
if (!cbList)
return -1;
/* If there is no additional filtering, then check if we already
* have this callback on our list. */
if (!filter &&
virObjectEventCallbackLookup(conn, cbList, key,
klass, eventID, callback, legacy,
serverFilter ? &remoteID : NULL) != -1) {
virReportError(VIR_ERR_INVALID_ARG, "%s",
_("event callback already tracked"));
return -1;
}
/* Allocate new cb */
if (VIR_ALLOC(cb) < 0)
goto cleanup;
cb->conn = virObjectRef(conn);
*callbackID = cb->callbackID = cbList->nextID++;
cb->cb = callback;
cb->klass = klass;
cb->eventID = eventID;
cb->opaque = opaque;
cb->freecb = freecb;
cb->remoteID = remoteID;
if (key) {
cb->key_filter = true;
if (VIR_STRDUP(cb->key, key) < 0)
goto cleanup;
}
cb->filter = filter;
cb->filter_opaque = filter_opaque;
cb->legacy = legacy;
if (VIR_APPEND_ELEMENT(cbList->callbacks, cbList->count, cb) < 0)
goto cleanup;
/* When additional filtering is being done, every client callback
* is matched to exactly one server callback. */
if (filter) {
ret = 1;
} else {
ret = virObjectEventCallbackListCount(conn, cbList, klass, eventID,
key, serverFilter);
if (serverFilter && remoteID < 0)
ret++;
}
cleanup:
virObjectEventCallbackFree(cb);
return ret;
}
/**
* virObjectEventQueueClear:
* @queue: pointer to the queue
*
* Removes all elements from the queue
*/
static void
virObjectEventQueueClear(virObjectEventQueuePtr queue)
{
size_t i;
if (!queue)
return;
for (i = 0; i < queue->count; i++)
virObjectUnref(queue->events[i]);
VIR_FREE(queue->events);
queue->count = 0;
}
/**
* virObjectEventQueueFree:
* @queue: pointer to the queue
*
* Free the memory in the queue. We process this like a list here
*/
static void
virObjectEventQueueFree(virObjectEventQueuePtr queue)
{
if (!queue)
return;
virObjectEventQueueClear(queue);
VIR_FREE(queue);
}
static virObjectEventQueuePtr
virObjectEventQueueNew(void)
{
virObjectEventQueuePtr ret;
ignore_value(VIR_ALLOC(ret));
return ret;
}
/**
* virObjectEventStateDispose:
* @list: virObjectEventStatePtr to free
*
* Free a virObjectEventStatePtr and its members, and unregister the timer.
*/
static void
virObjectEventStateDispose(void *obj)
{
virObjectEventStatePtr state = obj;
VIR_DEBUG("obj=%p", state);
virObjectEventCallbackListFree(state->callbacks);
virObjectEventQueueFree(state->queue);
if (state->timer != -1)
virEventRemoveTimeout(state->timer);
}
static void virObjectEventStateFlush(virObjectEventStatePtr state);
/**
* virObjectEventTimer:
* @timer: id of the event loop timer
* @opaque: the event state object
*
* Register this function with the event state as its opaque data as
* the callback of a periodic timer on the event loop, in order to
* flush the callback queue.
*/
static void
virObjectEventTimer(int timer ATTRIBUTE_UNUSED, void *opaque)
{
virObjectEventStatePtr state = opaque;
virObjectEventStateFlush(state);
}
/**
* virObjectEventStateNew:
*
* Allocate a new event state object.
*/
virObjectEventStatePtr
virObjectEventStateNew(void)
{
virObjectEventStatePtr state = NULL;
if (virObjectEventInitialize() < 0)
return NULL;
if (!(state = virObjectLockableNew(virObjectEventStateClass)))
return NULL;
if (VIR_ALLOC(state->callbacks) < 0)
goto error;
if (!(state->queue = virObjectEventQueueNew()))
goto error;
state->timer = -1;
return state;
error:
virObjectUnref(state);
return NULL;
}
/**
* virObjectEventNew:
* @klass: subclass of event to be created
* @dispatcher: callback for dispatching the particular subclass of event
* @eventID: id of the event
* @id: id of the object the event describes, or 0
* @name: name of the object the event describes
* @uuid: uuid of the object the event describes
* @key: key for per-object filtering
*
* Create a new event, with the information common to all events.
*/
void *
virObjectEventNew(virClassPtr klass,
virObjectEventDispatchFunc dispatcher,
int eventID,
int id,
const char *name,
const unsigned char *uuid,
const char *key)
{
virObjectEventPtr event;
if (virObjectEventInitialize() < 0)
return NULL;
if (!virClassIsDerivedFrom(klass, virObjectEventClass)) {
virReportInvalidArg(klass,
_("Class %s must derive from virObjectEvent"),
virClassName(klass));
return NULL;
}
if (!(event = virObjectNew(klass)))
return NULL;
event->dispatch = dispatcher;
event->eventID = eventID;
event->remoteID = -1;
if (VIR_STRDUP(event->meta.name, name) < 0 ||
VIR_STRDUP(event->meta.key, key) < 0) {
virObjectUnref(event);
return NULL;
}
event->meta.id = id;
if (uuid)
memcpy(event->meta.uuid, uuid, VIR_UUID_BUFLEN);
VIR_DEBUG("obj=%p", event);
return event;
}
/**
* virObjectEventQueuePush:
* @evtQueue: the object event queue
* @event: the event to add
*
* Internal function to push to the back of a virObjectEventQueue
*
* Returns: 0 on success, -1 on failure
*/
static int
virObjectEventQueuePush(virObjectEventQueuePtr evtQueue,
virObjectEventPtr event)
{
if (!evtQueue)
return -1;
if (VIR_APPEND_ELEMENT(evtQueue->events, evtQueue->count, event) < 0)
return -1;
return 0;
}
static bool
virObjectEventDispatchMatchCallback(virObjectEventPtr event,
virObjectEventCallbackPtr cb)
{
if (!cb)
return false;
if (cb->deleted)
return false;
if (!virObjectIsClass(event, cb->klass))
return false;
if (cb->eventID != event->eventID)
return false;
if (cb->remoteID != event->remoteID)
return false;
if (cb->filter && !(cb->filter)(cb->conn, event, cb->filter_opaque))
return false;
if (cb->key_filter)
return STREQ(event->meta.key, cb->key);
return true;
}
static void
virObjectEventStateDispatchCallbacks(virObjectEventStatePtr state,
virObjectEventPtr event,
virObjectEventCallbackListPtr callbacks)
{
size_t i;
/* Cache this now, since we may be dropping the lock,
and have more callbacks added. We're guaranteed not
to have any removed */
size_t cbCount = callbacks->count;
for (i = 0; i < cbCount; i++) {
virObjectEventCallbackPtr cb = callbacks->callbacks[i];
if (!virObjectEventDispatchMatchCallback(event, cb))
continue;
/* Drop the lock whle dispatching, for sake of re-entrancy */
virObjectUnlock(state);
event->dispatch(cb->conn, event, cb->cb, cb->opaque);
virObjectLock(state);
}
}
static void
virObjectEventStateQueueDispatch(virObjectEventStatePtr state,
virObjectEventQueuePtr queue,
virObjectEventCallbackListPtr callbacks)
{
size_t i;
for (i = 0; i < queue->count; i++) {
virObjectEventStateDispatchCallbacks(state, queue->events[i],
callbacks);
virObjectUnref(queue->events[i]);
}
VIR_FREE(queue->events);
queue->count = 0;
}
/**
* virObjectEventStateQueueRemote:
* @state: the event state object
* @event: event to add to the queue
* @remoteID: limit dispatch to callbacks with the same remote id
*
* Adds @event to the queue of events to be dispatched at the next
* safe moment. The caller should no longer use @event after this
* call. If @remoteID is non-negative, the event will only be sent to
* callbacks where virObjectEventStateSetRemote() registered a remote
* id.
*/
void
virObjectEventStateQueueRemote(virObjectEventStatePtr state,
virObjectEventPtr event,
int remoteID)
{
if (state->timer < 0) {
virObjectUnref(event);
return;
}
virObjectLock(state);
event->remoteID = remoteID;
if (virObjectEventQueuePush(state->queue, event) < 0) {
VIR_DEBUG("Error adding event to queue");
virObjectUnref(event);
}
if (state->queue->count == 1)
virEventUpdateTimeout(state->timer, 0);
virObjectUnlock(state);
}
/**
* virObjectEventStateQueue:
* @state: the event state object
* @event: event to add to the queue
*
* Adds @event to the queue of events to be dispatched at the next
* safe moment. The caller should no longer use @event after this
* call.
*/
void
virObjectEventStateQueue(virObjectEventStatePtr state,
virObjectEventPtr event)
{
virObjectEventStateQueueRemote(state, event, -1);
}
static void
virObjectEventStateCleanupTimer(virObjectEventStatePtr state, bool clear_queue)
{
/* There are still some callbacks, keep the timer. */
if (state->callbacks->count)
return;
/* The timer is not registered, nothing to do. */
if (state->timer == -1)
return;
virEventRemoveTimeout(state->timer);
state->timer = -1;
if (clear_queue)
virObjectEventQueueClear(state->queue);
}
static void
virObjectEventStateFlush(virObjectEventStatePtr state)
{
virObjectEventQueue tempQueue;
/* We need to lock as well as ref due to the fact that we might
* unref the state we're working on in this very function */
virObjectRef(state);
virObjectLock(state);
state->isDispatching = true;
/* Copy the queue, so we're reentrant safe when dispatchFunc drops the
* driver lock */
tempQueue.count = state->queue->count;
tempQueue.events = state->queue->events;
state->queue->count = 0;
state->queue->events = NULL;
if (state->timer != -1)
virEventUpdateTimeout(state->timer, -1);
virObjectEventStateQueueDispatch(state,
&tempQueue,
state->callbacks);
/* Purge any deleted callbacks */
virObjectEventCallbackListPurgeMarked(state->callbacks);
/* If we purged all callbacks, we need to remove the timeout as
* well like virObjectEventStateDeregisterID() would do. */
virObjectEventStateCleanupTimer(state, true);
state->isDispatching = false;
virObjectUnlock(state);
virObjectUnref(state);
}
/**
* virObjectEventStateRegisterID:
* @conn: connection to associate with callback
* @state: domain event state
* @key: key of the object for event filtering
* @klass: the base event class
* @eventID: ID of the event type to register for
* @cb: function to invoke when event occurs
* @opaque: data blob to pass to @callback
* @freecb: callback to free @opaque
* @legacy: true if callback is tracked by function instead of callbackID
* @callbackID: filled with callback ID
* @serverFilter: true if server supports object filtering
*
* Register the function @cb with connection @conn, from @state, for
* events of type @eventID, and return the registration handle in
* @callbackID.
*
* The return value is only important when registering client-side
* mirroring of remote events (since the public API is documented to
* return the callbackID rather than a count). A return of 1 means
* that this is the first use of this type of event, so a remote event
* must be enabled; a return larger than 1 means that an existing
* remote event can already feed this callback. If @serverFilter is
* false, the return count assumes that a single global remote feeds
* both generic and per-object callbacks, and that the event queue
* will be fed with virObjectEventStateQueue(). If it is true, then
* the return count assumes that the remote side is capable of per-
* object filtering; the user must call virObjectEventStateSetRemote()
* to record the remote id, and queue events with
* virObjectEventStateQueueRemote().
*
* Returns: the number of callbacks now registered, or -1 on error.
*/
int
virObjectEventStateRegisterID(virConnectPtr conn,
virObjectEventStatePtr state,
const char *key,
virObjectEventCallbackFilter filter,
void *filter_opaque,
virClassPtr klass,
int eventID,
virConnectObjectEventGenericCallback cb,
void *opaque,
virFreeCallback freecb,
bool legacy,
int *callbackID,
bool serverFilter)
{
int ret = -1;
virObjectLock(state);
if ((state->callbacks->count == 0) &&
(state->timer == -1) &&
(state->timer = virEventAddTimeout(-1,
virObjectEventTimer,
state,
virObjectFreeCallback)) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("could not initialize domain event timer"));
goto cleanup;
}
/* event loop has one reference, but we need one more for the
* timer's opaque argument */
virObjectRef(state);
ret = virObjectEventCallbackListAddID(conn, state->callbacks,
key, filter, filter_opaque,
klass, eventID,
cb, opaque, freecb,
legacy, callbackID, serverFilter);
if (ret < 0)
virObjectEventStateCleanupTimer(state, false);
cleanup:
virObjectUnlock(state);
return ret;
}
/**
* virObjectEventStateDeregisterID:
* @conn: connection to associate with callback
* @state: object event state
* @callbackID: ID of the function to remove from event
* @doFreeCb: Allow the calling of a freecb
*
* Unregister the function @callbackID with connection @conn,
* from @state, for events. If @doFreeCb is false, then we
* are being called from a remote call failure path for the
* Event registration indicating a -1 return to the caller. The
* caller wouldn't expect us to run their freecb function if it
* exists, so we cannot do so.
*
* Returns: the number of callbacks still registered, or -1 on error
*/
int
virObjectEventStateDeregisterID(virConnectPtr conn,
virObjectEventStatePtr state,
int callbackID,
bool doFreeCb)
{
int ret;
virObjectLock(state);
if (state->isDispatching)
ret = virObjectEventCallbackListMarkDeleteID(conn,
state->callbacks,
callbackID);
else
ret = virObjectEventCallbackListRemoveID(conn, state->callbacks,
callbackID, doFreeCb);
virObjectEventStateCleanupTimer(state, true);
virObjectUnlock(state);
return ret;
}
/**
* virObjectEventStateCallbackID:
* @conn: connection associated with callback
* @state: object event state
* @klass: the base event class
* @eventID: the event ID
* @callback: function registered as a callback
* @remoteID: optional output, containing resulting remote id
*
* Returns the callbackID of @callback, or -1 with an error issued if the
* function is not currently registered. This only finds functions
* registered via virConnectDomainEventRegister, even if modern style
* virConnectDomainEventRegisterAny also registers the same callback.
*/
int
virObjectEventStateCallbackID(virConnectPtr conn,
virObjectEventStatePtr state,
virClassPtr klass,
int eventID,
virConnectObjectEventGenericCallback callback,
int *remoteID)
{
int ret = -1;
virObjectLock(state);
ret = virObjectEventCallbackLookup(conn, state->callbacks, NULL,
klass, eventID, callback, true,
remoteID);
virObjectUnlock(state);
if (ret < 0)
virReportError(VIR_ERR_INVALID_ARG,
_("event callback function %p not registered"),
callback);
return ret;
}
/**
* virObjectEventStateEventID:
* @conn: connection associated with the callback
* @state: object event state
* @callbackID: the callback to query
* @remoteID: optionally output remote ID of the callback
*
* Query what event ID type is associated with the callback
* @callbackID for connection @conn. If @remoteID is non-null, it
* will be set to the remote id previously registered with
* virObjectEventStateSetRemote().
*
* Returns 0 on success, -1 on error
*/
int
virObjectEventStateEventID(virConnectPtr conn,
virObjectEventStatePtr state,
int callbackID,
int *remoteID)
{
int ret = -1;
size_t i;
virObjectEventCallbackListPtr cbList = state->callbacks;
virObjectLock(state);
for (i = 0; i < cbList->count; i++) {
virObjectEventCallbackPtr cb = cbList->callbacks[i];
if (cb->deleted)
continue;
if (cb->callbackID == callbackID && cb->conn == conn) {
if (remoteID)
*remoteID = cb->remoteID;
ret = cb->eventID;
break;
}
}
virObjectUnlock(state);
if (ret < 0)
virReportError(VIR_ERR_INVALID_ARG,
_("event callback id %d not registered"),
callbackID);
return ret;
}
/**
* virObjectEventStateSetRemote:
* @conn: connection associated with the callback
* @state: object event state
* @callbackID: the callback to adjust
* @remoteID: the remote ID to associate with the callback
*
* Update @callbackID for connection @conn to record that it is now
* tied to @remoteID, and will therefore only match events that are
* sent with virObjectEventStateQueueRemote() with the same remote ID.
* Silently does nothing if @callbackID is invalid.
*/
void
virObjectEventStateSetRemote(virConnectPtr conn,
virObjectEventStatePtr state,
int callbackID,
int remoteID)
{
size_t i;
virObjectLock(state);
for (i = 0; i < state->callbacks->count; i++) {
virObjectEventCallbackPtr cb = state->callbacks->callbacks[i];
if (cb->deleted)
continue;
if (cb->callbackID == callbackID && cb->conn == conn) {
cb->remoteID = remoteID;
break;
}
}
virObjectUnlock(state);
}
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