/*
* libvirt-glib-event.c: libvirt glib integration
*
* Copyright (C) 2008 Daniel P. Berrange
* Copyright (C) 2010-2011 Red Hat, Inc.
*
* 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: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <libvirt/libvirt.h>
#include "libvirt-glib/libvirt-glib.h"
/**
* SECTION:libvirt-glib-event
* @short_description: Integrate libvirt with the GMain event framework
* @title: Event loop
* @stability: Stable
* @include: libvirt-glib/libvirt-glib.h
*
* The libvirt API has the ability to provide applications with asynchronous
* notifications of interesting events. To enable this functionality though,
* applications must provide libvirt with an event loop implementation. The
* libvirt-glib API provides such an implementation, which naturally integrates
* with the GMain event loop framework.
*
* To enable use of the GMain event loop glue, the <code>gvir_event_register()</code>
* should be invoked. Once this is done, it is mandatory to have the default
* GMain event loop run by a thread in the application, usually the primary
* thread, eg by using <code>gtk_main()</code> or <code>g_application_run()</code>
*
* <example>
* <title>Registering for events with a GTK application</title>
* <programlisting><![CDATA[
* int main(int argc, char **argv) {
* ...setup...
* gvir_event_register();
* ...more setup...
* gtk_main();
* return 0;
* }
* ]]></programlisting>
* </example>
*
* <example>
* <title>Registering for events using Appplication</title>
* <programlisting><![CDATA[
* int main(int argc, char **argv) {
* ...setup...
* GApplication *app = ...create some impl of GApplication...
* gvir_event_register();
* ...more setup...
* g_application_run(app);
* return 0;
* }
* ]]></programlisting>
* </example>
*/
#if GLIB_CHECK_VERSION(2, 31, 0)
#define g_mutex_new() g_new0(GMutex, 1)
#endif
struct gvir_event_handle
{
int watch;
int fd;
int events;
int removed;
GIOChannel *channel;
guint source;
virEventHandleCallback cb;
void *opaque;
virFreeCallback ff;
};
struct gvir_event_timeout
{
int timer;
int interval;
int removed;
guint source;
virEventTimeoutCallback cb;
void *opaque;
virFreeCallback ff;
};
GMutex *eventlock = NULL;
static int nextwatch = 1;
static GPtrArray *handles;
static int nexttimer = 1;
static GPtrArray *timeouts;
static gboolean
gvir_event_handle_dispatch(GIOChannel *source G_GNUC_UNUSED,
GIOCondition condition,
gpointer opaque)
{
struct gvir_event_handle *data = opaque;
int events = 0;
if (condition & G_IO_IN)
events |= VIR_EVENT_HANDLE_READABLE;
if (condition & G_IO_OUT)
events |= VIR_EVENT_HANDLE_WRITABLE;
if (condition & G_IO_HUP)
events |= VIR_EVENT_HANDLE_HANGUP;
if (condition & G_IO_ERR)
events |= VIR_EVENT_HANDLE_ERROR;
g_debug("Dispatch handler %p %d %d %d %p\n", data, data->watch, data->fd, events, data->opaque);
(data->cb)(data->watch, data->fd, events, data->opaque);
return TRUE;
}
static int
gvir_event_handle_add(int fd,
int events,
virEventHandleCallback cb,
void *opaque,
virFreeCallback ff)
{
struct gvir_event_handle *data;
GIOCondition cond = 0;
int ret;
g_mutex_lock(eventlock);
data = g_new0(struct gvir_event_handle, 1);
if (events & VIR_EVENT_HANDLE_READABLE)
cond |= G_IO_IN;
if (events & VIR_EVENT_HANDLE_WRITABLE)
cond |= G_IO_OUT;
data->watch = nextwatch++;
data->fd = fd;
data->events = events;
data->cb = cb;
data->opaque = opaque;
data->channel = g_io_channel_unix_new(fd);
data->ff = ff;
g_debug("Add handle %p %d %d %d %p\n", data, data->watch, data->fd, events, data->opaque);
data->source = g_io_add_watch(data->channel,
cond,
gvir_event_handle_dispatch,
data);
g_ptr_array_add(handles, data);
ret = data->watch;
g_mutex_unlock(eventlock);
return ret;
}
static struct gvir_event_handle *
gvir_event_handle_find(int watch)
{
guint i;
for (i = 0 ; i < handles->len ; i++) {
struct gvir_event_handle *h = g_ptr_array_index(handles, i);
if (h == NULL) {
g_warn_if_reached ();
continue;
}
if ((h->watch == watch) && !h->removed) {
return h;
}
}
return NULL;
}
static void
gvir_event_handle_update(int watch,
int events)
{
struct gvir_event_handle *data;
g_mutex_lock(eventlock);
data = gvir_event_handle_find(watch);
if (!data) {
g_debug("Update for missing handle watch %d", watch);
goto cleanup;
}
g_debug("Update handle %p %d %d %d\n", data, watch, data->fd, events);
if (events) {
GIOCondition cond = 0;
if (events == data->events)
goto cleanup;
if (data->source)
g_source_remove(data->source);
cond |= G_IO_HUP;
if (events & VIR_EVENT_HANDLE_READABLE)
cond |= G_IO_IN;
if (events & VIR_EVENT_HANDLE_WRITABLE)
cond |= G_IO_OUT;
data->source = g_io_add_watch(data->channel,
cond,
gvir_event_handle_dispatch,
data);
data->events = events;
} else {
if (!data->source)
goto cleanup;
g_source_remove(data->source);
data->source = 0;
data->events = 0;
}
cleanup:
g_mutex_unlock(eventlock);
}
static gboolean
_event_handle_remove(gpointer data)
{
struct gvir_event_handle *h = data;
if (h->ff)
(h->ff)(h->opaque);
g_mutex_lock(eventlock);
g_ptr_array_remove_fast(handles, h);
g_mutex_unlock(eventlock);
return FALSE;
}
static int
gvir_event_handle_remove(int watch)
{
struct gvir_event_handle *data;
int ret = -1;
g_mutex_lock(eventlock);
data = gvir_event_handle_find(watch);
if (!data) {
g_debug("Remove of missing watch %d", watch);
goto cleanup;
}
g_debug("Remove handle %p %d %d\n", data, watch, data->fd);
if (!data->source)
goto cleanup;
g_source_remove(data->source);
data->source = 0;
data->events = 0;
/* since the actual watch deletion is done asynchronously, a handle_update call may
* reschedule the watch before it's fully deleted, that's why we need to mark it as
* 'removed' to prevent reuse
*/
data->removed = TRUE;
g_idle_add(_event_handle_remove, data);
ret = 0;
cleanup:
g_mutex_unlock(eventlock);
return ret;
}
static gboolean
gvir_event_timeout_dispatch(void *opaque)
{
struct gvir_event_timeout *data = opaque;
g_debug("Dispatch timeout %p %p %d %p\n", data, data->cb, data->timer, data->opaque);
(data->cb)(data->timer, data->opaque);
return TRUE;
}
static int
gvir_event_timeout_add(int interval,
virEventTimeoutCallback cb,
void *opaque,
virFreeCallback ff)
{
struct gvir_event_timeout *data;
int ret;
g_mutex_lock(eventlock);
data = g_new0(struct gvir_event_timeout, 1);
data->timer = nexttimer++;
data->interval = interval;
data->cb = cb;
data->opaque = opaque;
data->ff = ff;
if (interval >= 0)
data->source = g_timeout_add(interval,
gvir_event_timeout_dispatch,
data);
g_ptr_array_add(timeouts, data);
g_debug("Add timeout %p %d %p %p %d\n", data, interval, cb, opaque, data->timer);
ret = data->timer;
g_mutex_unlock(eventlock);
return ret;
}
static struct gvir_event_timeout *
gvir_event_timeout_find(int timer)
{
guint i;
g_return_val_if_fail(timeouts != NULL, NULL);
for (i = 0 ; i < timeouts->len ; i++) {
struct gvir_event_timeout *t = g_ptr_array_index(timeouts, i);
if (t == NULL) {
g_warn_if_reached ();
continue;
}
if ((t->timer == timer) && !t->removed) {
return t;
}
}
return NULL;
}
static void
gvir_event_timeout_update(int timer,
int interval)
{
struct gvir_event_timeout *data;
g_mutex_lock(eventlock);
data = gvir_event_timeout_find(timer);
if (!data) {
g_debug("Update of missing timer %d", timer);
goto cleanup;
}
g_debug("Update timeout %p %d %d\n", data, timer, interval);
if (interval >= 0) {
if (data->source)
g_source_remove(data->source);
data->interval = interval;
data->source = g_timeout_add(data->interval,
gvir_event_timeout_dispatch,
data);
} else {
if (!data->source)
goto cleanup;
g_source_remove(data->source);
data->source = 0;
}
cleanup:
g_mutex_unlock(eventlock);
}
static gboolean
_event_timeout_remove(gpointer data)
{
struct gvir_event_timeout *t = data;
if (t->ff)
(t->ff)(t->opaque);
g_mutex_lock(eventlock);
g_ptr_array_remove_fast(timeouts, t);
g_mutex_unlock(eventlock);
return FALSE;
}
static int
gvir_event_timeout_remove(int timer)
{
struct gvir_event_timeout *data;
int ret = -1;
g_mutex_lock(eventlock);
data = gvir_event_timeout_find(timer);
if (!data) {
g_debug("Remove of missing timer %d", timer);
goto cleanup;
}
g_debug("Remove timeout %p %d\n", data, timer);
if (!data->source)
goto cleanup;
g_source_remove(data->source);
data->source = 0;
/* since the actual timeout deletion is done asynchronously, a timeout_update call may
* reschedule the timeout before it's fully deleted, that's why we need to mark it as
* 'removed' to prevent reuse
*/
data->removed = TRUE;
g_idle_add(_event_timeout_remove, data);
ret = 0;
cleanup:
g_mutex_unlock(eventlock);
return ret;
}
static gpointer event_register_once(gpointer data G_GNUC_UNUSED)
{
eventlock = g_mutex_new();
timeouts = g_ptr_array_new_with_free_func(g_free);
handles = g_ptr_array_new_with_free_func(g_free);
virEventRegisterImpl(gvir_event_handle_add,
gvir_event_handle_update,
gvir_event_handle_remove,
gvir_event_timeout_add,
gvir_event_timeout_update,
gvir_event_timeout_remove);
return NULL;
}
/**
* gvir_event_register:
*
* Registers a libvirt event loop implementation that is backed
* by the default <code>GMain</code> context. If invoked more
* than once this method will be a no-op. Applications should,
* however, take care not to register any another non-GLib
* event loop with libvirt.
*
* After invoking this method, it is mandatory to run the
* default GMain event loop. Typically this can be satisfied
* by invoking <code>gtk_main</code> or <code>g_application_run</code>
* in the application's main thread. Failure to run the event
* loop will mean no libvirt events get dispatched, and the
* libvirt keepalive timer will kill off libvirt connections
* frequently.
*/
void gvir_event_register(void)
{
static GOnce once = G_ONCE_INIT;
g_once(&once, event_register_once, NULL);
}