/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/*
* Copyright © 2012 – 2017 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 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/>.
*/
#include "config.h"
#include "goaalarm.h"
#ifdef HAVE_TIMERFD
#include <sys/timerfd.h>
#endif
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <glib.h>
#include <gio/gio.h>
#include <gio/gunixinputstream.h>
#define MAX_TIMEOUT_INTERVAL (10 *1000)
typedef enum
{
GOA_ALARM_TYPE_UNSCHEDULED,
GOA_ALARM_TYPE_TIMER,
GOA_ALARM_TYPE_TIMEOUT,
} GoaAlarmType;
struct _GoaAlarmPrivate
{
GDateTime *time;
GDateTime *previous_wakeup_time;
GMainContext *context;
GSource *immediate_wakeup_source;
GRecMutex lock;
GoaAlarmType type;
GSource *scheduled_wakeup_source;
GInputStream *stream; /* NULL, unless using timerfd */
};
enum
{
FIRED,
REARMED,
NUMBER_OF_SIGNALS,
};
enum
{
PROP_0,
PROP_TIME
};
static void schedule_wakeups (GoaAlarm *self);
static void schedule_wakeups_with_timeout_source (GoaAlarm *self);
static void goa_alarm_set_time (GoaAlarm *self, GDateTime *time);
static void clear_wakeup_source_pointer (GoaAlarm *self);
static guint signals[NUMBER_OF_SIGNALS] = { 0 };
G_DEFINE_TYPE (GoaAlarm, goa_alarm, G_TYPE_OBJECT);
static void
goa_alarm_dispose (GObject *object)
{
GoaAlarm *self = GOA_ALARM (object);
g_clear_object (&self->priv->stream);
g_clear_pointer (&self->priv->immediate_wakeup_source, (GDestroyNotify) g_source_destroy);
g_clear_pointer (&self->priv->scheduled_wakeup_source, (GDestroyNotify) g_source_destroy);
g_clear_pointer (&self->priv->context, (GDestroyNotify) g_main_context_unref);
g_clear_pointer (&self->priv->time, (GDestroyNotify) g_date_time_unref);
g_clear_pointer (&self->priv->previous_wakeup_time, (GDestroyNotify) g_date_time_unref);
G_OBJECT_CLASS (goa_alarm_parent_class)->dispose (object);
}
static void
goa_alarm_finalize (GObject *object)
{
GoaAlarm *self = GOA_ALARM (object);
g_rec_mutex_clear (&self->priv->lock);
G_OBJECT_CLASS (goa_alarm_parent_class)->finalize (object);
}
static void
goa_alarm_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *param_spec)
{
GoaAlarm *self = GOA_ALARM (object);
GDateTime *time;
switch (property_id)
{
case PROP_TIME:
time = (GDateTime *) g_value_get_boxed (value);
goa_alarm_set_time (self, time);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, param_spec);
break;
}
}
static void
goa_alarm_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *param_spec)
{
GoaAlarm *self = GOA_ALARM (object);
switch (property_id)
{
case PROP_TIME:
g_value_set_boxed (value, self->priv->time);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, param_spec);
break;
}
}
static void
goa_alarm_class_init (GoaAlarmClass *klass)
{
GObjectClass *object_class;
object_class = G_OBJECT_CLASS (klass);
object_class->dispose = goa_alarm_dispose;
object_class->finalize = goa_alarm_finalize;
object_class->get_property = goa_alarm_get_property;
object_class->set_property = goa_alarm_set_property;
g_type_class_add_private (klass, sizeof (GoaAlarmPrivate));
signals[FIRED] = g_signal_new ("fired",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
0, NULL, NULL, NULL, G_TYPE_NONE, 0);
signals[REARMED] = g_signal_new ("rearmed",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
0, NULL, NULL, NULL, G_TYPE_NONE, 0);
g_object_class_install_property (object_class,
PROP_TIME,
g_param_spec_boxed ("time",
"Time",
"Time to fire",
G_TYPE_DATE_TIME,
G_PARAM_READWRITE));
}
static void
goa_alarm_init (GoaAlarm *self)
{
self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, GOA_TYPE_ALARM, GoaAlarmPrivate);
g_rec_mutex_init (&self->priv->lock);
}
static void
fire_alarm (GoaAlarm *self)
{
g_signal_emit (G_OBJECT (self), signals[FIRED], 0);
}
static void
rearm_alarm (GoaAlarm *self)
{
g_signal_emit (G_OBJECT (self), signals[REARMED], 0);
}
static void
fire_or_rearm_alarm (GoaAlarm *self)
{
GTimeSpan time_until_fire;
GTimeSpan previous_time_until_fire;
GDateTime *now;
now = g_date_time_new_now_local ();
time_until_fire = g_date_time_difference (self->priv->time, now);
if (self->priv->previous_wakeup_time == NULL)
{
self->priv->previous_wakeup_time = now;
/* If, according to the time, we're past when we should have fired,
* then fire the alarm.
*/
if (time_until_fire <= 0)
fire_alarm (self);
}
else
{
previous_time_until_fire =
g_date_time_difference (self->priv->time,
self->priv->previous_wakeup_time);
g_date_time_unref (self->priv->previous_wakeup_time);
self->priv->previous_wakeup_time = now;
/* If, according to the time, we're past when we should have fired,
* and this is the first wakeup where that's been true then fire
* the alarm. The first check makes sure we don't fire prematurely,
* and the second check makes sure we don't fire more than once
*/
if (time_until_fire <= 0 && previous_time_until_fire > 0)
{
fire_alarm (self);
/* If, according to the time, we're before when we should fire,
* and we previously fired the alarm, then we've jumped back in
* time and need to rearm the alarm.
*/
}
else if (time_until_fire > 0 && previous_time_until_fire <= 0)
{
rearm_alarm (self);
}
}
}
static gboolean
on_immediate_wakeup_source_ready (GoaAlarm *self)
{
g_return_val_if_fail (self->priv->type != GOA_ALARM_TYPE_UNSCHEDULED, FALSE);
g_rec_mutex_lock (&self->priv->lock);
fire_or_rearm_alarm (self);
g_rec_mutex_unlock (&self->priv->lock);
return FALSE;
}
#ifdef HAVE_TIMERFD
static gboolean
on_timer_source_ready (GObject *stream, GoaAlarm *self)
{
gint64 number_of_fires;
gssize bytes_read;
gboolean run_again = FALSE;
GError *error = NULL;
g_return_val_if_fail (GOA_IS_ALARM (self), FALSE);
g_rec_mutex_lock (&self->priv->lock);
if (self->priv->type != GOA_ALARM_TYPE_TIMER)
{
g_warning ("GoaAlarm: timer source ready callback called "
"when timer source isn't supposed to be used. "
"Current timer type is %u", self->priv->type);
goto out;
}
bytes_read =
g_pollable_input_stream_read_nonblocking (G_POLLABLE_INPUT_STREAM (stream),
&number_of_fires, sizeof (gint64),
NULL, &error);
if (bytes_read < 0)
{
if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
g_debug ("GoaAlarm: discontinuity detected from timer fd");
else
{
g_warning ("GoaAlarm: failed to read from timer fd: %s\n",
error->message);
goto out;
}
}
if (bytes_read == sizeof (gint64))
{
if (number_of_fires < 0 || number_of_fires > 1)
{
g_warning ("GoaAlarm: expected timerfd to report firing once,"
"but it reported firing %ld times\n", (long) number_of_fires);
}
}
fire_or_rearm_alarm (self);
run_again = TRUE;
out:
g_rec_mutex_unlock (&self->priv->lock);
g_clear_error (&error);
return run_again;
}
#endif
static gboolean
schedule_wakeups_with_timerfd (GoaAlarm *self)
{
#ifdef HAVE_TIMERFD
struct itimerspec timer_spec;
int fd;
int result;
GSource *source;
static gboolean seen_before = FALSE;
if (!seen_before)
{
g_debug ("GoaAlarm: trying to use kernel timer");
seen_before = TRUE;
}
fd = timerfd_create (CLOCK_REALTIME, TFD_CLOEXEC | TFD_NONBLOCK);
if (fd < 0)
{
g_debug ("GoaAlarm: could not create timer fd: %s", strerror (errno));
return FALSE;
}
memset (&timer_spec, 0, sizeof (timer_spec));
timer_spec.it_value.tv_sec = g_date_time_to_unix (self->priv->time) + 1;
result = timerfd_settime (fd,
TFD_TIMER_ABSTIME | TFD_TIMER_CANCEL_ON_SET,
&timer_spec, NULL);
if (result < 0)
{
g_debug ("GoaAlarm: could not set timer: %s", strerror (errno));
return FALSE;
}
self->priv->type = GOA_ALARM_TYPE_TIMER;
self->priv->stream = g_unix_input_stream_new (fd, TRUE);
source =
g_pollable_input_stream_create_source (G_POLLABLE_INPUT_STREAM
(self->priv->stream),
NULL);
self->priv->scheduled_wakeup_source = source;
g_source_set_callback (self->priv->scheduled_wakeup_source,
(GSourceFunc) on_timer_source_ready, self,
(GDestroyNotify) clear_wakeup_source_pointer);
g_source_attach (self->priv->scheduled_wakeup_source, self->priv->context);
g_source_unref (source);
return TRUE;
#endif /*HAVE_TIMERFD */
return FALSE;
}
static gboolean
on_timeout_source_ready (GoaAlarm *self)
{
g_return_val_if_fail (GOA_IS_ALARM (self), FALSE);
g_rec_mutex_lock (&self->priv->lock);
if (self->priv->type == GOA_ALARM_TYPE_UNSCHEDULED)
goto out;
fire_or_rearm_alarm (self);
schedule_wakeups_with_timeout_source (self);
out:
g_rec_mutex_unlock (&self->priv->lock);
return FALSE;
}
static void
clear_wakeup_source_pointer (GoaAlarm *self)
{
self->priv->scheduled_wakeup_source = NULL;
}
static void
schedule_wakeups_with_timeout_source (GoaAlarm *self)
{
GDateTime *now;
GSource *source;
GTimeSpan time_span;
guint interval;
self->priv->type = GOA_ALARM_TYPE_TIMEOUT;
now = g_date_time_new_now_local ();
time_span = g_date_time_difference (self->priv->time, now);
g_date_time_unref (now);
time_span =
CLAMP (time_span, 1000 *G_TIME_SPAN_MILLISECOND,
G_MAXUINT *G_TIME_SPAN_MILLISECOND);
interval = (guint) time_span / G_TIME_SPAN_MILLISECOND;
/* We poll every 10 seconds or so because we want to catch time skew
*/
interval = MIN (interval, MAX_TIMEOUT_INTERVAL);
source = g_timeout_source_new (interval);
self->priv->scheduled_wakeup_source = source;
g_source_set_callback (self->priv->scheduled_wakeup_source,
(GSourceFunc)
on_timeout_source_ready,
self, (GDestroyNotify) clear_wakeup_source_pointer);
g_source_attach (self->priv->scheduled_wakeup_source, self->priv->context);
g_source_unref (source);
}
static void
schedule_wakeups (GoaAlarm *self)
{
gboolean wakeup_scheduled;
wakeup_scheduled = schedule_wakeups_with_timerfd (self);
if (!wakeup_scheduled)
{
static gboolean seen_before = FALSE;
if (!seen_before)
{
g_debug ("GoaAlarm: falling back to polling timeout");
seen_before = TRUE;
}
schedule_wakeups_with_timeout_source (self);
}
}
static void
clear_immediate_wakeup_source_pointer (GoaAlarm *self)
{
self->priv->immediate_wakeup_source = NULL;
}
static void
schedule_immediate_wakeup (GoaAlarm *self)
{
GSource *source;
source = g_idle_source_new ();
self->priv->immediate_wakeup_source = source;
g_source_set_callback (self->priv->immediate_wakeup_source,
(GSourceFunc)
on_immediate_wakeup_source_ready,
self,
(GDestroyNotify) clear_immediate_wakeup_source_pointer);
g_source_attach (self->priv->immediate_wakeup_source, self->priv->context);
g_source_unref (source);
}
static void
goa_alarm_set_time (GoaAlarm *self, GDateTime *time)
{
g_rec_mutex_lock (&self->priv->lock);
g_date_time_ref (time);
self->priv->time = time;
if (self->priv->context == NULL)
self->priv->context = g_main_context_ref (g_main_context_default ());
schedule_wakeups (self);
/* Wake up right away, in case it's already expired leaving the gate */
schedule_immediate_wakeup (self);
g_rec_mutex_unlock (&self->priv->lock);
g_object_notify (G_OBJECT (self), "time");
}
GDateTime *
goa_alarm_get_time (GoaAlarm *self)
{
return self->priv->time;
}
GoaAlarm *
goa_alarm_new (GDateTime *alarm_time)
{
GoaAlarm *self;
self = GOA_ALARM (g_object_new (GOA_TYPE_ALARM, "time", alarm_time, NULL));
return GOA_ALARM (self);
}