freetdm: add force hangup timer and refactor scheduling code

libs/freetdm/src/ftdm_io.c

@@ -102,6 +102,7 @@ static struct {
 	ftdm_mutex_t *mutex;
 	ftdm_mutex_t *span_mutex;
 	ftdm_mutex_t *group_mutex;
+	ftdm_sched_t *timingsched;
 	uint32_t span_index;
 	uint32_t group_index;
 	uint32_t running;
@@ -2002,6 +2003,9 @@ static ftdm_status_t call_hangup(ftdm_channel_t *chan, const char *file, const c
 			/* make user's life easier, and just ignore double hangup requests */
 			return FTDM_SUCCESS;
 		}
+		if (chan->hangup_timer) {
+			ftdm_sched_cancel_timer(globals.timingsched, chan->hangup_timer);
+		}
 		ftdm_channel_set_state(file, func, line, chan, FTDM_CHANNEL_STATE_HANGUP, 1);
 	} else {
 		/* the signaling stack did not touch the state, 
@@ -2283,6 +2287,9 @@ FT_DECLARE(ftdm_status_t) ftdm_channel_done(ftdm_channel_t *ftdmchan)
 	close_dtmf_debug(ftdmchan);
 #endif
 	ftdm_channel_clear_vars(ftdmchan);
+	if (ftdmchan->hangup_timer) {
+		ftdm_sched_cancel_timer(globals.timingsched, ftdmchan->hangup_timer);
+	}
 
 	ftdmchan->init_state = FTDM_CHANNEL_STATE_DOWN;
 	ftdmchan->state = FTDM_CHANNEL_STATE_DOWN;
@@ -4601,6 +4608,21 @@ FT_DECLARE(ftdm_status_t) ftdm_span_trigger_signals(const ftdm_span_t *span)
 	return FTDM_SUCCESS;
 }
 
+
+static void execute_safety_hangup(void *data)
+{
+	ftdm_channel_t *fchan = data;
+	ftdm_channel_lock(fchan);
+	fchan->hangup_timer = 0;
+	if (fchan->state == FTDM_CHANNEL_STATE_TERMINATING) {
+		ftdm_log_chan_msg(fchan, FTDM_LOG_CRIT, "Forcing hangup\n");
+		ftdm_channel_call_hangup(fchan);
+	} else {
+		ftdm_log_chan(fchan, FTDM_LOG_CRIT, "Not performing safety hangup, channel state is %s\n", ftdm_channel_state2str(fchan->state));
+	}
+	ftdm_channel_unlock(fchan);
+}
+
 FT_DECLARE(ftdm_status_t) ftdm_span_send_signal(ftdm_span_t *span, ftdm_sigmsg_t *sigmsg)
 {
 	if (sigmsg->channel) {
@@ -4634,6 +4656,11 @@ FT_DECLARE(ftdm_status_t) ftdm_span_send_signal(ftdm_span_t *span, ftdm_sigmsg_t
 			ftdm_log_chan_msg(sigmsg->channel, FTDM_LOG_DEBUG, "Ignoring SIGEVENT_STOP since user already requested hangup\n");
 			goto done;
 		}
+		if (sigmsg->channel->state == FTDM_CHANNEL_STATE_TERMINATING) {
+			ftdm_log_chan_msg(sigmsg->channel, FTDM_LOG_DEBUG, "Scheduling safety hangup timer\n");
+			/* if the user does not move us to hangup in 2 seconds, we will do it ourselves */
+			ftdm_sched_timer(globals.timingsched, "safety-hangup", 2000, execute_safety_hangup, sigmsg->channel, &sigmsg->channel->hangup_timer);
+		}
 		break;
 
 	default:
@@ -4755,6 +4782,14 @@ FT_DECLARE(ftdm_status_t) ftdm_global_init(void)
 	ftdm_mutex_create(&globals.span_mutex);
 	ftdm_mutex_create(&globals.group_mutex);
 	ftdm_sched_global_init();
+	if (ftdm_sched_create(&globals.timingsched, "freetdm-master") != FTDM_SUCCESS) {
+		ftdm_log(FTDM_LOG_CRIT, "Failed to create master timing schedule context\n");
+		return FTDM_FAIL;
+	}
+	if (ftdm_sched_free_run(globals.timingsched) != FTDM_SUCCESS) {
+		ftdm_log(FTDM_LOG_CRIT, "Failed to run master timing schedule context\n");
+		return FTDM_FAIL;
+	}
 	globals.running = 1;
 	return FTDM_SUCCESS;
 }
@@ -4807,6 +4842,8 @@ FT_DECLARE(ftdm_status_t) ftdm_global_destroy(void)
 
 	globals.running = 0;	
 
+	ftdm_sched_destroy(&globals.timingsched);
+
 	ftdm_cpu_monitor_stop();
 
 	globals.span_index = 0;

libs/freetdm/src/ftdm_sched.c

@@ -34,6 +34,8 @@
 
 #include "private/ftdm_core.h"
 
+typedef struct ftdm_timer ftdm_timer_t;
+
 static struct {
 	ftdm_sched_t *freeruns;
 	ftdm_mutex_t *mutex;
@@ -42,6 +44,7 @@ static struct {
 
 struct ftdm_sched {
 	char name[80];
+	ftdm_timer_id_t currid;
 	ftdm_mutex_t *mutex;
 	ftdm_timer_t *timers;
 	int freerun;
@@ -51,6 +54,7 @@ struct ftdm_sched {
 
 struct ftdm_timer {
 	char name[80];
+	ftdm_timer_id_t id;
 #ifdef __linux__
 	struct timeval time;
 #endif
@@ -191,6 +195,7 @@ FT_DECLARE(ftdm_status_t) ftdm_sched_create(ftdm_sched_t **sched, const char *na
 	}
 
 	ftdm_set_string(newsched->name, name);
+	newsched->currid = 1;
 
 	*sched = newsched;
 	ftdm_log(FTDM_LOG_DEBUG, "Created schedule %s\n", name);
@@ -219,12 +224,13 @@ FT_DECLARE(ftdm_status_t) ftdm_sched_run(ftdm_sched_t *sched)
 	int rc = -1;
 	void *data;
 	struct timeval now;
+
 	ftdm_assert_return(sched != NULL, FTDM_EINVAL, "sched is null!\n");
 
-	ftdm_mutex_lock(sched->mutex);
-
 tryagain:
 
+	ftdm_mutex_lock(sched->mutex);
+
 	rc = gettimeofday(&now, NULL);
 	if (rc == -1) {
 		ftdm_log(FTDM_LOG_ERROR, "Failed to retrieve time of day\n");
@@ -257,11 +263,16 @@ tryagain:
 				runtimer->prev->next = runtimer->next;
 			}
 
+			runtimer->id = 0;
 			ftdm_safe_free(runtimer);
 
+			/* avoid deadlocks by releasing the sched lock before triggering callbacks */
+			ftdm_mutex_unlock(sched->mutex);
+
 			callback(data);
 			/* after calling a callback we must start the scanning again since the
-			 * callback may have added or cancelled timers to the linked list */
+			 * callback or some other thread may have added or cancelled timers to 
+			 * the linked list */
 			goto tryagain;
 		}
 	}
@@ -283,7 +294,7 @@ done:
 }
 
 FT_DECLARE(ftdm_status_t) ftdm_sched_timer(ftdm_sched_t *sched, const char *name, 
-		int ms, ftdm_sched_callback_t callback, void *data, ftdm_timer_t **timer)
+		int ms, ftdm_sched_callback_t callback, void *data, ftdm_timer_id_t *timerid)
 {
 	ftdm_status_t status = FTDM_FAIL;
 #ifdef __linux__
@@ -296,8 +307,8 @@ FT_DECLARE(ftdm_status_t) ftdm_sched_timer(ftdm_sched_t *sched, const char *name
 	ftdm_assert_return(callback != NULL, FTDM_EINVAL, "sched callback is null!\n");
 	ftdm_assert_return(ms > 0, FTDM_EINVAL, "milliseconds must be bigger than 0!\n");
 
-	if (timer) {
-		*timer = NULL;
+	if (timerid) {
+		*timerid = 0;
 	}
 
 	rc = gettimeofday(&now, NULL);
@@ -312,6 +323,8 @@ FT_DECLARE(ftdm_status_t) ftdm_sched_timer(ftdm_sched_t *sched, const char *name
 	if (!newtimer) {
 		goto done;
 	}
+	newtimer->id = sched->currid;
+	sched->currid++;
 
 	ftdm_set_string(newtimer->name, name);
 	newtimer->callback = callback;
@@ -332,9 +345,10 @@ FT_DECLARE(ftdm_status_t) ftdm_sched_timer(ftdm_sched_t *sched, const char *name
 		sched->timers = newtimer;
 	}
 
-	if (timer) {
-		*timer = newtimer;
+	if (timerid) {
+		*timerid = newtimer->id;
 	}
+
 	status = FTDM_SUCCESS;
 done:
 
@@ -418,53 +432,37 @@ done:
 	return status;
 }
 
-FT_DECLARE(ftdm_status_t) ftdm_sched_cancel_timer(ftdm_sched_t *sched, ftdm_timer_t **intimer)
+FT_DECLARE(ftdm_status_t) ftdm_sched_cancel_timer(ftdm_sched_t *sched, ftdm_timer_id_t timerid)
 {
 	ftdm_status_t status = FTDM_FAIL;
 	ftdm_timer_t *timer;
 
 	ftdm_assert_return(sched != NULL, FTDM_EINVAL, "sched is null!\n");
-	ftdm_assert_return(intimer != NULL, FTDM_EINVAL, "timer is null!\n");
-	ftdm_assert_return(*intimer != NULL, FTDM_EINVAL, "timer is null!\n");
+
+	if (!timerid) {
+		return FTDM_SUCCESS;
+	}
 
 	ftdm_mutex_lock(sched->mutex);
 
-	/* special case where the cancelled timer is the head */
-	if (*intimer == sched->timers) {
-		timer = *intimer;
-		/* the timer next is the new head (even if that means the new head will be NULL)*/
-		sched->timers = timer->next;
-		/* if there is a new head, clean its prev member */
-		if (sched->timers) {
-			sched->timers->prev = NULL;
-		}
-		/* free the old head */
-		ftdm_safe_free(timer);
-		status = FTDM_SUCCESS;
-		*intimer = NULL;
-		goto done;
-	}
-
-	/* look for the timer and destroy it (we know now that is not head, se we start at the next member after head) */
-	for (timer = sched->timers->next; timer; timer = timer->next) {
-		if (timer == *intimer) {
+	/* look for the timer and destroy it */
+	for (timer = sched->timers; timer; timer = timer->next) {
+		if (timer->id == timerid) {
+			if (timer == sched->timers) {
+				/* it's the head timer, put a new head */
+				sched->timers = timer->next;
+			}
 			if (timer->prev) {
 				timer->prev->next = timer->next;
 			}
 			if (timer->next) {
 				timer->next->prev = timer->prev;
 			}
-			ftdm_log(FTDM_LOG_DEBUG, "cancelled timer %s\n", timer->name);
 			ftdm_safe_free(timer);
 			status = FTDM_SUCCESS;
-			*intimer = NULL;
 			break;
 		}
 	}
-done:
-	if (status == FTDM_FAIL) {
-		ftdm_log(FTDM_LOG_ERROR, "Could not find timer %s to cancel it\n", (*intimer)->name);
-	}
 
 	ftdm_mutex_unlock(sched->mutex);
 

libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn.h

@@ -156,7 +156,7 @@ typedef struct sngisdn_chan_data {
 
 	uint8_t                 globalFlg;
 	sngisdn_glare_data_t	glare;
-	ftdm_timer_t 			*timers[SNGISDN_NUM_TIMERS];
+	ftdm_timer_id_t 		timers[SNGISDN_NUM_TIMERS];
 } sngisdn_chan_data_t;
 
 /* Span specific data */

libs/freetdm/src/ftmod/ftmod_sangoma_isdn/ftmod_sangoma_isdn_stack_hndl.c

@@ -709,7 +709,7 @@ void sngisdn_process_fac_ind (sngisdn_event_data_t *sngisdn_event)
 					ftdm_log_chan_msg(ftdmchan, FTDM_LOG_WARNING, "Failed to retrieve Caller Name from Facility IE\n");
 				}
 				/* Cancel facility timeout */
-				ftdm_sched_cancel_timer(signal_data->sched, &sngisdn_info->timers[SNGISDN_TIMER_FACILITY]);
+				ftdm_sched_cancel_timer(signal_data->sched, sngisdn_info->timers[SNGISDN_TIMER_FACILITY]);
 			}
 
 			ftdm_set_state(ftdmchan, FTDM_CHANNEL_STATE_RING);

libs/freetdm/src/include/private/ftdm_core.h

@@ -425,6 +425,7 @@ struct ftdm_channel {
 	float txgain;
 	int availability_rate;
 	void *user_private;
+	ftdm_timer_id_t hangup_timer;
 #ifdef FTDM_DEBUG_DTMF
 	ftdm_dtmf_debug_t dtmfdbg;
 #endif

libs/freetdm/src/include/private/ftdm_sched.h

@@ -44,8 +44,8 @@ extern "C" {
 #define FTDM_MICROSECONDS_PER_SECOND 1000000
 
 typedef struct ftdm_sched ftdm_sched_t;
-typedef struct ftdm_timer ftdm_timer_t;
 typedef void (*ftdm_sched_callback_t)(void *data);
+typedef uint64_t ftdm_timer_id_t;
 
 /*! \brief Create a new scheduling context */
 FT_DECLARE(ftdm_status_t) ftdm_sched_create(ftdm_sched_t **sched, const char *name);
@@ -62,18 +62,22 @@ FT_DECLARE(ftdm_status_t) ftdm_sched_free_run(ftdm_sched_t *sched);
  * \param name Timer name, typically unique but is not required to be unique, any null terminated string is fine (required)
  * \param callback The callback to call upon timer expiration (required)
  * \param data Optional data to pass to the callback
- * \param timer The timer that was created, it can be NULL if you dont care, 
- *        but you need this if you want to be able to cancel the timer with ftdm_sched_cancel_timer
+ * \param timer Timer id pointer to store the id of the newly created timer. It can be null
+ *              if you do not need to know the id, but you need this if you want to be able 
+ *              to cancel the timer with ftdm_sched_cancel_timer
  */
 FT_DECLARE(ftdm_status_t) ftdm_sched_timer(ftdm_sched_t *sched, const char *name, 
-		int ms, ftdm_sched_callback_t callback, void *data, ftdm_timer_t **timer);
+		int ms, ftdm_sched_callback_t callback, void *data, ftdm_timer_id_t *timer);
 
 /*! 
  * \brief Cancel the timer
+ *        Note that there is a race between cancelling and triggering a timer.
+ *        By the time you call this function the timer may be about to be triggered.
+ *        This is specially true with timers in free run schedule.
  * \param sched The scheduling context (required)
  * \param timer The timer to cancel (required)
  */
-FT_DECLARE(ftdm_status_t) ftdm_sched_cancel_timer(ftdm_sched_t *sched, ftdm_timer_t **timer);
+FT_DECLARE(ftdm_status_t) ftdm_sched_cancel_timer(ftdm_sched_t *sched, ftdm_timer_id_t timer);
 
 /*! \brief Destroy the context and all of the scheduled timers in it */
 FT_DECLARE(ftdm_status_t) ftdm_sched_destroy(ftdm_sched_t **sched);