Merge changes from topic 'ASTERISK-26343' into 14

* changes:
  channel: Use frame deferral API for safe sleep.
  autoservice: Use frame deferral API
  AGI: Only defer frames when in an interception routine.
  Add API for channel frame deferral.

include/asterisk/channel.h

@@ -967,6 +967,11 @@ enum {
 	 * The channel is executing a subroutine or macro
 	 */
 	AST_FLAG_SUBROUTINE_EXEC = (1 << 27),
+	/*!
+	 * The channel is currently in an operation where
+	 * frames should be deferred.
+	 */
+	AST_FLAG_DEFER_FRAMES = (1 << 28),
 };
 
 /*! \brief ast_bridge_config flags */
@@ -4661,4 +4666,37 @@ enum ast_channel_error {
  */
 enum ast_channel_error ast_channel_errno(void);
 
+/*!
+ * \brief Retrieve the deferred read queue.
+ */
+struct ast_readq_list *ast_channel_deferred_readq(struct ast_channel *chan);
+
+/*!
+ * \brief Start deferring deferrable frames on this channel
+ *
+ * Sometimes, a channel gets entered into a mode where a "main" application
+ * is tasked with servicing frames on the channel, but that application does
+ * not need to act on those frames. However, it would be imprudent to simply
+ * drop important frames. This function can be called so that important frames
+ * will be deferred, rather than placed in the channel frame queue as normal.
+ *
+ * \pre chan MUST be locked before calling
+ *
+ * \param chan The channel on which frames should be deferred
+ */
+void ast_channel_start_defer_frames(struct ast_channel *chan);
+
+/*!
+ * \brief Stop deferring deferrable frames on this channel
+ *
+ * When it is time to stop deferring frames on the channel, all deferred frames
+ * will be queued onto the channel's read queue so that the next servicer of
+ * the channel can handle those frames as necessary.
+ *
+ * \pre chan MUST be locked before calling
+ *
+ * \param chan The channel on which to stop deferring frames.
+ */
+void ast_channel_stop_defer_frames(struct ast_channel *chan);
+
 #endif /* _ASTERISK_CHANNEL_H */

main/autoservice.c

@@ -61,10 +61,6 @@ struct asent {
 	unsigned int use_count;
 	unsigned int orig_end_dtmf_flag:1;
 	unsigned int ignore_frame_types;
-	/*! Frames go on at the head of deferred_frames, so we have the frames
-	 *  from newest to oldest.  As we put them at the head of the readq, we'll
-	 *  end up with them in the right order for the channel's readq. */
-	AST_LIST_HEAD_NOLOCK(, ast_frame) deferred_frames;
 	AST_LIST_ENTRY(asent) list;
 };
 
@@ -79,19 +75,13 @@ static int as_chan_list_state;
 static void *autoservice_run(void *ign)
 {
 	ast_callid callid = 0;
-	struct ast_frame hangup_frame = {
-		.frametype = AST_FRAME_CONTROL,
-		.subclass.integer = AST_CONTROL_HANGUP,
-	};
 
 	while (!asexit) {
 		struct ast_channel *mons[MAX_AUTOMONS];
-		struct asent *ents[MAX_AUTOMONS];
 		struct ast_channel *chan;
 		struct asent *as;
-		int i, x = 0, ms = 50;
+		int x = 0, ms = 50;
 		struct ast_frame *f = NULL;
-		struct ast_frame *defer_frame = NULL;
 
 		AST_LIST_LOCK(&aslist);
 
@@ -106,7 +96,6 @@ static void *autoservice_run(void *ign)
 		AST_LIST_TRAVERSE(&aslist, as, list) {
 			if (!ast_check_hangup(as->chan)) {
 				if (x < MAX_AUTOMONS) {
-					ents[x] = as;
 					mons[x++] = as->chan;
 				} else {
 					ast_log(LOG_WARNING, "Exceeded maximum number of automatic monitoring events.  Fix autoservice.c\n");
@@ -134,51 +123,9 @@ static void *autoservice_run(void *ign)
 		ast_callid_threadassoc_change(callid);
 
 		f = ast_read(chan);
-
-		if (!f) {
-			/* No frame means the channel has been hung up.
-			 * A hangup frame needs to be queued here as ast_waitfor() may
-			 * never return again for the condition to be detected outside
-			 * of autoservice.  So, we'll leave a HANGUP queued up so the
-			 * thread in charge of this channel will know. */
-
-			defer_frame = &hangup_frame;
-		} else if (ast_is_deferrable_frame(f)) {
-			defer_frame = f;
-		} else {
-			/* Can't defer. Discard and continue with next. */
+		if (f) {
 			ast_frfree(f);
-			continue;
 		}
-
-		for (i = 0; i < x; i++) {
-			struct ast_frame *dup_f;
-
-			if (mons[i] != chan) {
-				continue;
-			}
-
-			if (!f) { /* defer_frame == &hangup_frame */
-				if ((dup_f = ast_frdup(defer_frame))) {
-					AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
-				}
-			} else {
-				if ((dup_f = ast_frisolate(defer_frame))) {
-					AST_LIST_INSERT_HEAD(&ents[i]->deferred_frames, dup_f, frame_list);
-				}
-				if (dup_f != defer_frame) {
-					ast_frfree(defer_frame);
-				}
-			}
-
-			break;
-		}
-		/* The ast_waitfor_n() call will only read frames from
-		 * the channels' file descriptors. If ast_waitfor_n()
-		 * returns non-NULL, then one of the channels in the
-		 * mons array must have triggered the return. It's
-		 * therefore impossible that we got here while (i >= x).
-		 * If we did, we'd need to ast_frfree(f) if (f). */
 	}
 
 	ast_callid_threadassoc_change(0);
@@ -217,6 +164,7 @@ int ast_autoservice_start(struct ast_channel *chan)
 	as->orig_end_dtmf_flag = ast_test_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY) ? 1 : 0;
 	if (!as->orig_end_dtmf_flag)
 		ast_set_flag(ast_channel_flags(chan), AST_FLAG_END_DTMF_ONLY);
+	ast_channel_start_defer_frames(chan);
 	ast_channel_unlock(chan);
 
 	AST_LIST_LOCK(&aslist);
@@ -250,7 +198,6 @@ int ast_autoservice_stop(struct ast_channel *chan)
 {
 	int res = -1;
 	struct asent *as, *removed = NULL;
-	struct ast_frame *f;
 	int chan_list_state;
 
 	AST_LIST_LOCK(&aslist);
@@ -302,12 +249,7 @@ int ast_autoservice_stop(struct ast_channel *chan)
 	}
 
 	ast_channel_lock(chan);
-	while ((f = AST_LIST_REMOVE_HEAD(&as->deferred_frames, frame_list))) {
-		if (!((1 << f->frametype) & as->ignore_frame_types)) {
-			ast_queue_frame_head(chan, f);
-		}
-		ast_frfree(f);
-	}
+	ast_channel_stop_defer_frames(chan);
 	ast_channel_unlock(chan);
 
 	ast_free(as);

main/channel.c

@@ -1064,6 +1064,25 @@ struct ast_channel *__ast_dummy_channel_alloc(const char *file, int line, const
 	return tmp;
 }
 
+void ast_channel_start_defer_frames(struct ast_channel *chan)
+{
+	ast_set_flag(ast_channel_flags(chan), AST_FLAG_DEFER_FRAMES);
+}
+
+void ast_channel_stop_defer_frames(struct ast_channel *chan)
+{
+	ast_clear_flag(ast_channel_flags(chan), AST_FLAG_DEFER_FRAMES);
+
+	/* Move the deferred frames onto the channel read queue, ahead of other queued frames */
+	ast_queue_frame_head(chan, AST_LIST_FIRST(ast_channel_deferred_readq(chan)));
+	/* ast_frfree will mosey down the list and free them all */
+	if (!AST_LIST_EMPTY(ast_channel_deferred_readq(chan))) {
+		ast_frfree(AST_LIST_FIRST(ast_channel_deferred_readq(chan)));
+	}
+	/* Reset the list to be empty */
+	AST_LIST_HEAD_INIT_NOLOCK(ast_channel_deferred_readq(chan));
+}
+
 static int __ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin, int head, struct ast_frame *after)
 {
 	struct ast_frame *f;
@@ -1527,19 +1546,18 @@ int ast_safe_sleep_conditional(struct ast_channel *chan, int timeout_ms, int (*c
 	int res = 0;
 	struct timeval start;
 	int ms;
-	AST_LIST_HEAD_NOLOCK(, ast_frame) deferred_frames;
-
-	AST_LIST_HEAD_INIT_NOLOCK(&deferred_frames);
 
 	/* If no other generator is present, start silencegen while waiting */
 	if (ast_opt_transmit_silence && !ast_channel_generatordata(chan)) {
 		silgen = ast_channel_start_silence_generator(chan);
 	}
 
+	ast_channel_lock(chan);
+	ast_channel_start_defer_frames(chan);
+	ast_channel_unlock(chan);
+
 	start = ast_tvnow();
 	while ((ms = ast_remaining_ms(start, timeout_ms))) {
-		struct ast_frame *dup_f = NULL;
-
 		if (cond && ((*cond)(data) == 0)) {
 			break;
 		}
@@ -1554,18 +1572,7 @@ int ast_safe_sleep_conditional(struct ast_channel *chan, int timeout_ms, int (*c
 				res = -1;
 				break;
 			}
-
-			if (!ast_is_deferrable_frame(f)) {
-				ast_frfree(f);
-				continue;
-			}
-
-			if ((dup_f = ast_frisolate(f))) {
-				if (dup_f != f) {
-					ast_frfree(f);
-				}
-				AST_LIST_INSERT_HEAD(&deferred_frames, dup_f, frame_list);
-			}
+			ast_frfree(f);
 		}
 	}
 
@@ -1574,17 +1581,8 @@ int ast_safe_sleep_conditional(struct ast_channel *chan, int timeout_ms, int (*c
 		ast_channel_stop_silence_generator(chan, silgen);
 	}
 
-	/* We need to free all the deferred frames, but we only need to
-	 * queue the deferred frames if there was no error and no
-	 * hangup was received
-	 */
 	ast_channel_lock(chan);
-	while ((f = AST_LIST_REMOVE_HEAD(&deferred_frames, frame_list))) {
-		if (!res) {
-			ast_queue_frame_head(chan, f);
-		}
-		ast_frfree(f);
-	}
+	ast_channel_stop_defer_frames(chan);
 	ast_channel_unlock(chan);
 
 	return res;
@@ -3885,6 +3883,32 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 	if (!AST_LIST_EMPTY(ast_channel_readq(chan))) {
 		int skip_dtmf = should_skip_dtmf(chan);
 
+		if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_FRAMES)) {
+			AST_LIST_TRAVERSE_SAFE_BEGIN(ast_channel_readq(chan), f, frame_list) {
+				if (ast_is_deferrable_frame(f)) {
+					if (f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_HANGUP) {
+						struct ast_frame *dup;
+
+						/* Hangup is a special case. We want to defer the frame, but we also do not
+						 * want to remove it from the frame queue. So rather than just moving the frame
+						 * over, we duplicate it and move the copy to the deferred readq.
+						 *
+						 * The reason for this? This way, whoever calls ast_read() will get a NULL return
+						 * immediately and can tell the channel has hung up and do what it needs to. Also,
+						 * when frame deferral finishes, then whoever calls ast_read() next will also get
+						 * the hangup.
+						 */
+						dup = ast_frdup(f);
+						AST_LIST_INSERT_TAIL(ast_channel_deferred_readq(chan), dup, frame_list);
+					} else {
+						AST_LIST_INSERT_TAIL(ast_channel_deferred_readq(chan), f, frame_list);
+						AST_LIST_REMOVE_CURRENT(frame_list);
+					}
+				}
+			}
+			AST_LIST_TRAVERSE_SAFE_END;
+		}
+
 		AST_LIST_TRAVERSE_SAFE_BEGIN(ast_channel_readq(chan), f, frame_list) {
 			/* We have to be picky about which frame we pull off of the readq because
 			 * there are cases where we want to leave DTMF frames on the queue until
@@ -10216,9 +10240,15 @@ int ast_channel_connected_line_macro(struct ast_channel *autoservice_chan, struc
 
 		ast_party_connected_line_copy(ast_channel_connected(macro_chan), connected);
 	}
+	ast_channel_start_defer_frames(macro_chan);
 	ast_channel_unlock(macro_chan);
 
 	retval = ast_app_run_macro(autoservice_chan, macro_chan, macro, macro_args);
+
+	ast_channel_lock(macro_chan);
+	ast_channel_stop_defer_frames(macro_chan);
+	ast_channel_unlock(macro_chan);
+
 	if (!retval) {
 		struct ast_party_connected_line saved_connected;
 
@@ -10266,9 +10296,15 @@ int ast_channel_redirecting_macro(struct ast_channel *autoservice_chan, struct a
 
 		ast_party_redirecting_copy(ast_channel_redirecting(macro_chan), redirecting);
 	}
+	ast_channel_start_defer_frames(macro_chan);
 	ast_channel_unlock(macro_chan);
 
 	retval = ast_app_run_macro(autoservice_chan, macro_chan, macro, macro_args);
+
+	ast_channel_lock(macro_chan);
+	ast_channel_stop_defer_frames(macro_chan);
+	ast_channel_unlock(macro_chan);
+
 	if (!retval) {
 		struct ast_party_redirecting saved_redirecting;
 
@@ -10309,9 +10345,15 @@ int ast_channel_connected_line_sub(struct ast_channel *autoservice_chan, struct
 
 		ast_party_connected_line_copy(ast_channel_connected(sub_chan), connected);
 	}
+	ast_channel_start_defer_frames(sub_chan);
 	ast_channel_unlock(sub_chan);
 
 	retval = ast_app_run_sub(autoservice_chan, sub_chan, sub, sub_args, 0);
+
+	ast_channel_lock(sub_chan);
+	ast_channel_stop_defer_frames(sub_chan);
+	ast_channel_unlock(sub_chan);
+
 	if (!retval) {
 		struct ast_party_connected_line saved_connected;
 
@@ -10352,9 +10394,15 @@ int ast_channel_redirecting_sub(struct ast_channel *autoservice_chan, struct ast
 
 		ast_party_redirecting_copy(ast_channel_redirecting(sub_chan), redirecting);
 	}
+	ast_channel_start_defer_frames(sub_chan);
 	ast_channel_unlock(sub_chan);
 
 	retval = ast_app_run_sub(autoservice_chan, sub_chan, sub, sub_args, 0);
+
+	ast_channel_lock(sub_chan);
+	ast_channel_stop_defer_frames(sub_chan);
+	ast_channel_unlock(sub_chan);
+
 	if (!retval) {
 		struct ast_party_redirecting saved_redirecting;
 

main/channel_internal_api.c

@@ -223,6 +223,7 @@ struct ast_channel {
 	struct stasis_cp_single *topics;		/*!< Topic for all channel's events */
 	struct stasis_forward *endpoint_forward;	/*!< Subscription for event forwarding to endpoint's topic */
 	struct stasis_forward *endpoint_cache_forward; /*!< Subscription for cache updates to endpoint's topic */
+	struct ast_readq_list deferred_readq;
 };
 
 /*! \brief The monotonically increasing integer counter for channel uniqueids */
@@ -1683,3 +1684,8 @@ enum ast_channel_error ast_channel_internal_errno(void)
 
 	return *error_code;
 }
+
+struct ast_readq_list *ast_channel_deferred_readq(struct ast_channel *chan)
+{
+	return &chan->deferred_readq;
+}

res/res_agi.c

@@ -4093,23 +4093,6 @@ static enum agi_result agi_handle_command(struct ast_channel *chan, AGI *agi, ch
 	return AGI_RESULT_SUCCESS;
 }
 
-AST_LIST_HEAD_NOLOCK(deferred_frames, ast_frame);
-
-static void queue_deferred_frames(struct deferred_frames *deferred_frames,
-	struct ast_channel *chan)
-{
-	struct ast_frame *f;
-
-	if (!AST_LIST_EMPTY(deferred_frames)) {
-		ast_channel_lock(chan);
-		while ((f = AST_LIST_REMOVE_HEAD(deferred_frames, frame_list))) {
-			ast_queue_frame_head(chan, f);
-			ast_frfree(f);
-		}
-		ast_channel_unlock(chan);
-	}
-}
-
 static enum agi_result run_agi(struct ast_channel *chan, char *request, AGI *agi, int pid, int *status, int dead, int argc, char *argv[])
 {
 	struct ast_channel *c;
@@ -4128,9 +4111,6 @@ static enum agi_result run_agi(struct ast_channel *chan, char *request, AGI *agi
 	const char *sighup_str;
 	const char *exit_on_hangup_str;
 	int exit_on_hangup;
-	struct deferred_frames deferred_frames;
-
-	AST_LIST_HEAD_INIT_NOLOCK(&deferred_frames);
 
 	ast_channel_lock(chan);
 	sighup_str = pbx_builtin_getvar_helper(chan, "AGISIGHUP");
@@ -4192,20 +4172,8 @@ static enum agi_result run_agi(struct ast_channel *chan, char *request, AGI *agi
 					/* Write, ignoring errors */
 					if (write(agi->audio, f->data.ptr, f->datalen) < 0) {
 					}
-					ast_frfree(f);
-				} else if (ast_is_deferrable_frame(f)) {
-					struct ast_frame *dup_f;
-
-					if ((dup_f = ast_frisolate(f))) {
-						AST_LIST_INSERT_HEAD(&deferred_frames, dup_f, frame_list);
-					}
-
-					if (dup_f != f) {
-						ast_frfree(f);
-					}
-				} else {
-					ast_frfree(f);
 				}
+				ast_frfree(f);
 			}
 		} else if (outfd > -1) {
 			size_t len = sizeof(buf);
@@ -4253,8 +4221,6 @@ static enum agi_result run_agi(struct ast_channel *chan, char *request, AGI *agi
 				buf[buflen - 1] = '\0';
 			}
 
-			queue_deferred_frames(&deferred_frames, chan);
-
 			if (agidebug)
 				ast_verbose("<%s>AGI Rx << %s\n", ast_channel_name(chan), buf);
 			cmd_status = agi_handle_command(chan, agi, buf, dead);
@@ -4277,8 +4243,6 @@ static enum agi_result run_agi(struct ast_channel *chan, char *request, AGI *agi
 		}
 	}
 
-	queue_deferred_frames(&deferred_frames, chan);
-
 	if (agi->speech) {
 		ast_speech_destroy(agi->speech);
 	}