ARI: Adding a channel to a bridge while a live recording is active blocks

Added the ability to have rules that are checked when adding and/or removing
channels to/from a bridge.  In this case, if a channel is currently recording
and someone attempts to add it to a bridge an "is recording" rule is checked,
fails, and a 409 conflict is returned.

Also command functions now return an integer value that can be descriptive of
what kind of problems, if any, occurred before or during execution.

(closes issue ASTERISK-22624)
Reported by: Joshua Colp
Review: https://reviewboard.asterisk.org/r/2947/
........

Merged revisions 403749 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@403750 65c4cc65-6c06-0410-ace0-fbb531ad65f3

3 files changed, 201 insertions, 71 deletions

diff --git a/res/stasis/command.c b/res/stasis/command.c
index f1f7f8f3b..a9e53af12 100644
--- a/res/stasis/command.c
+++ b/res/stasis/command.c
@@ -37,7 +37,7 @@ struct stasis_app_command {
 	ast_cond_t condition;
 	stasis_app_command_cb callback;
 	void *data;
-	void *retval;
+	int retval;
 	int is_done:1;
 };
 
@@ -67,7 +67,7 @@ struct stasis_app_command *command_create(
 	return command;
 }
 
-static void command_complete(struct stasis_app_command *command, void *retval)
+void command_complete(struct stasis_app_command *command, int retval)
 {
 	SCOPED_MUTEX(lock, &command->lock);
 
@@ -76,7 +76,7 @@ static void command_complete(struct stasis_app_command *command, void *retval)
 	ast_cond_signal(&command->condition);
 }
 
-void *command_join(struct stasis_app_command *command)
+int command_join(struct stasis_app_command *command)
 {
 	SCOPED_MUTEX(lock, &command->lock);
 	while (!command->is_done) {
@@ -89,7 +89,7 @@ void *command_join(struct stasis_app_command *command)
 void command_invoke(struct stasis_app_command *command,
 	struct stasis_app_control *control, struct ast_channel *chan)
 {
-	void *retval = command->callback(control, chan, command->data);
+	int retval = command->callback(control, chan, command->data);
 	command_complete(command, retval);
 }
 
diff --git a/res/stasis/command.h b/res/stasis/command.h
index 21f4df0c0..a99d40d0a 100644
--- a/res/stasis/command.h
+++ b/res/stasis/command.h
@@ -34,9 +34,11 @@ struct stasis_app_command;
 struct stasis_app_command *command_create(
 	stasis_app_command_cb callback, void *data);
 
+void command_complete(struct stasis_app_command *command, int retval);
+
 void command_invoke(struct stasis_app_command *command,
 	struct stasis_app_control *control, struct ast_channel *chan);
 
-void *command_join(struct stasis_app_command *command);
+int command_join(struct stasis_app_command *command);
 
 #endif /* _ASTERISK_RES_STASIS_CONTROL_H */
diff --git a/res/stasis/control.c b/res/stasis/control.c
index 14c9f57f5..6b092918e 100644
--- a/res/stasis/control.c
+++ b/res/stasis/control.c
@@ -40,6 +40,8 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/musiconhold.h"
 #include "asterisk/app.h"
 
+AST_LIST_HEAD(app_control_rules, stasis_app_control_rule);
+
 struct stasis_app_control {
 	ast_cond_t wait_cond;
 	/*! Queue of commands to dispatch on the channel */
@@ -59,6 +61,14 @@ struct stasis_app_control {
 	 */
 	struct ast_pbx *pbx;
 	/*!
+	 * A list of rules to check before adding a channel to a bridge.
+	 */
+	struct app_control_rules add_rules;
+	/*!
+	 * A list of rules to check before removing a channel from a bridge.
+	 */
+	struct app_control_rules remove_rules;
+	/*!
 	 * Silence generator, when silence is being generated.
 	 */
 	struct ast_silence_generator *silgen;
@@ -72,6 +82,9 @@ static void control_dtor(void *obj)
 {
 	struct stasis_app_control *control = obj;
 
+	AST_LIST_HEAD_DESTROY(&control->add_rules);
+	AST_LIST_HEAD_DESTROY(&control->remove_rules);
+
 	/* We may have a lingering silence generator; free it */
 	ast_channel_stop_silence_generator(control->channel, control->silgen);
 	control->silgen = NULL;
@@ -106,22 +119,121 @@ struct stasis_app_control *control_create(struct ast_channel *channel)
 
 	control->channel = channel;
 
+	AST_LIST_HEAD_INIT(&control->add_rules);
+	AST_LIST_HEAD_INIT(&control->remove_rules);
+
 	ao2_ref(control, +1);
 	return control;
 }
 
-static void *noop_cb(struct stasis_app_control *control,
+static void app_control_register_rule(
+	const struct stasis_app_control *control,
+	struct app_control_rules *list, struct stasis_app_control_rule *obj)
+{
+	SCOPED_AO2LOCK(lock, control->command_queue);
+	AST_LIST_INSERT_TAIL(list, obj, next);
+}
+
+static void app_control_unregister_rule(
+	const struct stasis_app_control *control,
+	struct app_control_rules *list, struct stasis_app_control_rule *obj)
+{
+	struct stasis_app_control_rule *rule;
+	SCOPED_AO2LOCK(lock, control->command_queue);
+	AST_RWLIST_TRAVERSE_SAFE_BEGIN(list, rule, next) {
+		if (rule == obj) {
+			AST_RWLIST_REMOVE_CURRENT(next);
+			break;
+		}
+	}
+	AST_RWLIST_TRAVERSE_SAFE_END;
+}
+
+/*!
+ * \internal
+ * \brief Checks to make sure each rule in the given list passes.
+ *
+ * \details Loops over a list of rules checking for rejections or failures.
+ *          If one rule fails its resulting error code is returned.
+ *
+ * \note Command queue should be locked before calling this function.
+ *
+ * \param control The stasis application control
+ * \param list The list of rules to check
+ *
+ * \retval 0 if all rules pass
+ * \retval non-zero error code if a rule fails
+ */
+static enum stasis_app_control_channel_result app_control_check_rules(
+	const struct stasis_app_control *control,
+	struct app_control_rules *list)
+{
+	int res = 0;
+	struct stasis_app_control_rule *rule;
+	AST_LIST_TRAVERSE(list, rule, next) {
+		if ((res = rule->check_rule(control))) {
+			return res;
+		}
+	}
+	return res;
+}
+
+void stasis_app_control_register_add_rule(
+	struct stasis_app_control *control,
+	struct stasis_app_control_rule *rule)
+{
+	return app_control_register_rule(control, &control->add_rules, rule);
+}
+
+void stasis_app_control_unregister_add_rule(
+	struct stasis_app_control *control,
+	struct stasis_app_control_rule *rule)
+{
+	app_control_unregister_rule(control, &control->add_rules, rule);
+}
+
+void stasis_app_control_register_remove_rule(
+	struct stasis_app_control *control,
+	struct stasis_app_control_rule *rule)
+{
+	return app_control_register_rule(control, &control->remove_rules, rule);
+}
+
+void stasis_app_control_unregister_remove_rule(
+	struct stasis_app_control *control,
+	struct stasis_app_control_rule *rule)
+{
+	app_control_unregister_rule(control, &control->remove_rules, rule);
+}
+
+static int app_control_can_add_channel_to_bridge(
+	struct stasis_app_control *control)
+{
+	return app_control_check_rules(control, &control->add_rules);
+}
+
+static int app_control_can_remove_channel_from_bridge(
+	struct stasis_app_control *control)
+{
+	return app_control_check_rules(control, &control->remove_rules);
+}
+
+static int noop_cb(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
-	return NULL;
+	return 0;
 }
 
+/*! Callback type to see if the command can execute
+    note: command_queue is locked during callback */
+typedef int (*app_command_can_exec_cb)(struct stasis_app_control *control);
 
-static struct stasis_app_command *exec_command(
+static struct stasis_app_command *exec_command_on_condition(
 	struct stasis_app_control *control, stasis_app_command_cb command_fn,
-	void *data)
+	void *data, app_command_can_exec_cb can_exec_fn)
 {
-	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
+	int retval;
+	struct stasis_app_command *command;
 
 	command_fn = command_fn ? : noop_cb;
 
@@ -131,24 +243,36 @@ static struct stasis_app_command *exec_command(
 	}
 
 	ao2_lock(control->command_queue);
+	if (can_exec_fn && (retval = can_exec_fn(control))) {
+		ao2_unlock(control->command_queue);
+		command_complete(command, retval);
+		return command;
+	}
+
 	ao2_link_flags(control->command_queue, command, OBJ_NOLOCK);
 	ast_cond_signal(&control->wait_cond);
 	ao2_unlock(control->command_queue);
 
-	ao2_ref(command, +1);
 	return command;
 }
 
+static struct stasis_app_command *exec_command(
+	struct stasis_app_control *control, stasis_app_command_cb command_fn,
+	void *data)
+{
+	return exec_command_on_condition(control, command_fn, data, NULL);
+}
+
 struct stasis_app_control_dial_data {
 	char endpoint[AST_CHANNEL_NAME];
 	int timeout;
 };
 
-static void *app_control_add_channel_to_bridge(
+static int app_control_add_channel_to_bridge(
         struct stasis_app_control *control,
         struct ast_channel *chan, void *data);
 
-static void *app_control_dial(struct stasis_app_control *control,
+static int app_control_dial(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	RAII_VAR(struct ast_dial *, dial, ast_dial_create(), ast_dial_destroy);
@@ -160,30 +284,30 @@ static void *app_control_dial(struct stasis_app_control *control,
 
 	tech = dial_data->endpoint;
 	if (!(resource = strchr(tech, '/'))) {
-		return NULL;
+		return -1;
 	}
 	*resource++ = '\0';
 
 	if (!dial) {
 		ast_log(LOG_ERROR, "Failed to create dialing structure.\n");
-		return NULL;
+		return -1;
 	}
 
 	if (ast_dial_append(dial, tech, resource) < 0) {
 		ast_log(LOG_ERROR, "Failed to add %s/%s to dialing structure.\n", tech, resource);
-		return NULL;
+		return -1;
 	}
 
 	ast_dial_set_global_timeout(dial, dial_data->timeout);
 
 	res = ast_dial_run(dial, NULL, 0);
 	if (res != AST_DIAL_RESULT_ANSWERED || !(new_chan = ast_dial_answered_steal(dial))) {
-		return NULL;
+		return -1;
 	}
 
 	if (!(bridge = ast_bridge_basic_new())) {
 		ast_log(LOG_ERROR, "Failed to create basic bridge.\n");
-		return NULL;
+		return -1;
 	}
 
 	if (ast_bridge_impart(bridge, new_chan, NULL, NULL,
@@ -193,7 +317,7 @@ static void *app_control_dial(struct stasis_app_control *control,
 		app_control_add_channel_to_bridge(control, chan, bridge);
 	}
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_dial(struct stasis_app_control *control, const char *endpoint, const char *exten, const char *context,
@@ -248,7 +372,7 @@ struct stasis_app_control_continue_data {
 	int priority;
 };
 
-static void *app_control_continue(struct stasis_app_control *control,
+static int app_control_continue(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	RAII_VAR(struct stasis_app_control_continue_data *, continue_data, data, ast_free);
@@ -266,7 +390,7 @@ static void *app_control_continue(struct stasis_app_control *control,
 
 	control->is_done = 1;
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_continue(struct stasis_app_control *control, const char *context, const char *extension, int priority)
@@ -297,7 +421,7 @@ struct stasis_app_control_dtmf_data {
 	char dtmf[];
 };
 
-static void *app_control_dtmf(struct stasis_app_control *control,
+static int app_control_dtmf(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	RAII_VAR(struct stasis_app_control_dtmf_data *, dtmf_data, data, ast_free);
@@ -312,7 +436,7 @@ static void *app_control_dtmf(struct stasis_app_control *control,
 		ast_safe_sleep(chan, dtmf_data->after);
 	}
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_dtmf(struct stasis_app_control *control, const char *dtmf, int before, int between, unsigned int duration, int after)
@@ -334,12 +458,12 @@ int stasis_app_control_dtmf(struct stasis_app_control *control, const char *dtmf
 	return 0;
 }
 
-static void *app_control_ring(struct stasis_app_control *control,
+static int app_control_ring(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	ast_indicate(control->channel, AST_CONTROL_RINGING);
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_ring(struct stasis_app_control *control)
@@ -349,12 +473,12 @@ int stasis_app_control_ring(struct stasis_app_control *control)
 	return 0;
 }
 
-static void *app_control_ring_stop(struct stasis_app_control *control,
+static int app_control_ring_stop(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	ast_indicate(control->channel, -1);
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_ring_stop(struct stasis_app_control *control)
@@ -369,7 +493,7 @@ struct stasis_app_control_mute_data {
 	unsigned int direction;
 };
 
-static void *app_control_mute(struct stasis_app_control *control,
+static int app_control_mute(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	RAII_VAR(struct stasis_app_control_mute_data *, mute_data, data, ast_free);
@@ -377,7 +501,7 @@ static void *app_control_mute(struct stasis_app_control *control,
 
 	ast_channel_suppress(control->channel, mute_data->direction, mute_data->frametype);
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_mute(struct stasis_app_control *control, unsigned int direction, enum ast_frame_type frametype)
@@ -396,7 +520,7 @@ int stasis_app_control_mute(struct stasis_app_control *control, unsigned int dir
 	return 0;
 }
 
-static void *app_control_unmute(struct stasis_app_control *control,
+static int app_control_unmute(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	RAII_VAR(struct stasis_app_control_mute_data *, mute_data, data, ast_free);
@@ -404,7 +528,7 @@ static void *app_control_unmute(struct stasis_app_control *control,
 
 	ast_channel_unsuppress(control->channel, mute_data->direction, mute_data->frametype);
 
-	return NULL;
+	return 0;
 }
 
 int stasis_app_control_unmute(struct stasis_app_control *control, unsigned int direction, enum ast_frame_type frametype)
@@ -456,12 +580,12 @@ int stasis_app_control_set_channel_var(struct stasis_app_control *control, const
 	return pbx_builtin_setvar_helper(control->channel, variable, value);
 }
 
-static void *app_control_hold(struct stasis_app_control *control,
+static int app_control_hold(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	ast_indicate(control->channel, AST_CONTROL_HOLD);
 
-	return NULL;
+	return 0;
 }
 
 void stasis_app_control_hold(struct stasis_app_control *control)
@@ -469,12 +593,12 @@ void stasis_app_control_hold(struct stasis_app_control *control)
 	stasis_app_send_command_async(control, app_control_hold, NULL);
 }
 
-static void *app_control_unhold(struct stasis_app_control *control,
+static int app_control_unhold(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	ast_indicate(control->channel, AST_CONTROL_UNHOLD);
 
-	return NULL;
+	return 0;
 }
 
 void stasis_app_control_unhold(struct stasis_app_control *control)
@@ -482,7 +606,7 @@ void stasis_app_control_unhold(struct stasis_app_control *control)
 	stasis_app_send_command_async(control, app_control_unhold, NULL);
 }
 
-static void *app_control_moh_start(struct stasis_app_control *control,
+static int app_control_moh_start(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	char *moh_class = data;
@@ -490,7 +614,7 @@ static void *app_control_moh_start(struct stasis_app_control *control,
 	ast_moh_start(chan, moh_class, NULL);
 
 	ast_free(moh_class);
-	return NULL;
+	return 0;
 }
 
 void stasis_app_control_moh_start(struct stasis_app_control *control, const char *moh_class)
@@ -504,11 +628,11 @@ void stasis_app_control_moh_start(struct stasis_app_control *control, const char
 	stasis_app_send_command_async(control, app_control_moh_start, data);
 }
 
-static void *app_control_moh_stop(struct stasis_app_control *control,
+static int app_control_moh_stop(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	ast_moh_stop(chan);
-	return NULL;
+	return 0;
 }
 
 void stasis_app_control_moh_stop(struct stasis_app_control *control)
@@ -516,7 +640,7 @@ void stasis_app_control_moh_stop(struct stasis_app_control *control)
 	stasis_app_send_command_async(control, app_control_moh_stop, NULL);
 }
 
-static void *app_control_silence_start(struct stasis_app_control *control,
+static int app_control_silence_start(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	if (control->silgen) {
@@ -538,7 +662,7 @@ static void *app_control_silence_start(struct stasis_app_control *control,
 			stasis_app_control_get_channel_id(control));
 	}
 
-	return NULL;
+	return 0;
 }
 
 void stasis_app_control_silence_start(struct stasis_app_control *control)
@@ -546,7 +670,7 @@ void stasis_app_control_silence_start(struct stasis_app_control *control)
 	stasis_app_send_command_async(control, app_control_silence_start, NULL);
 }
 
-static void *app_control_silence_stop(struct stasis_app_control *control,
+static int app_control_silence_stop(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	if (control->silgen) {
@@ -557,7 +681,7 @@ static void *app_control_silence_stop(struct stasis_app_control *control,
 		control->silgen = NULL;
 	}
 
-	return NULL;
+	return 0;
 }
 
 void stasis_app_control_silence_stop(struct stasis_app_control *control)
@@ -584,23 +708,31 @@ struct ast_channel_snapshot *stasis_app_control_get_snapshot(
 	return snapshot;
 }
 
-void *stasis_app_send_command(struct stasis_app_control *control,
-	stasis_app_command_cb command_fn, void *data)
+static int app_send_command_on_condition(struct stasis_app_control *control,
+					 stasis_app_command_cb command_fn, void *data,
+					 app_command_can_exec_cb can_exec_fn)
 {
 	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
 
 	if (control == NULL) {
-		return NULL;
+		return -1;
 	}
 
-	command = exec_command(control, command_fn, data);
+	command = exec_command_on_condition(
+		control, command_fn, data, can_exec_fn);
 	if (!command) {
-		return NULL;
+		return -1;
 	}
 
 	return command_join(command);
 }
 
+int stasis_app_send_command(struct stasis_app_control *control,
+	stasis_app_command_cb command_fn, void *data)
+{
+	return app_send_command_on_condition(control, command_fn, data, NULL);
+}
+
 int stasis_app_send_command_async(struct stasis_app_control *control,
 	stasis_app_command_cb command_fn, void *data)
 {
@@ -628,7 +760,7 @@ struct ast_bridge *stasis_app_get_bridge(struct stasis_app_control *control)
 	}
 }
 
-static void *bridge_channel_depart(struct stasis_app_control *control,
+static int bridge_channel_depart(struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	RAII_VAR(struct ast_bridge_channel *, bridge_channel, data, ao2_cleanup);
@@ -639,7 +771,7 @@ static void *bridge_channel_depart(struct stasis_app_control *control,
 		if (bridge_channel != ast_channel_internal_bridge_channel(chan)) {
 			ast_debug(3, "%s: Channel is no longer in departable state\n",
 				ast_channel_uniqueid(chan));
-			return NULL;
+			return -1;
 		}
 	}
 
@@ -648,7 +780,7 @@ static void *bridge_channel_depart(struct stasis_app_control *control,
 
 	ast_bridge_depart(chan);
 
-	return NULL;
+	return 0;
 }
 
 static void bridge_after_cb(struct ast_channel *chan, void *data)
@@ -691,10 +823,7 @@ static void bridge_after_cb_failed(enum ast_bridge_after_cb_reason reason,
 		ast_bridge_after_cb_reason_string(reason));
 }
 
-static int OK = 0;
-static int FAIL = -1;
-
-static void *app_control_add_channel_to_bridge(
+static int app_control_add_channel_to_bridge(
 	struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
@@ -702,7 +831,7 @@ static void *app_control_add_channel_to_bridge(
 	int res;
 
 	if (!control || !bridge) {
-		return NULL;
+		return -1;
 	}
 
 	ast_debug(3, "%s: Adding to bridge %s\n",
@@ -726,7 +855,7 @@ static void *app_control_add_channel_to_bridge(
 		bridge_after_cb_failed, control);
 	if (res != 0) {
 		ast_log(LOG_ERROR, "Error setting after-bridge callback\n");
-		return &FAIL;
+		return -1;
 	}
 
 	{
@@ -752,34 +881,34 @@ static void *app_control_add_channel_to_bridge(
 			ast_log(LOG_ERROR, "Error adding channel to bridge\n");
 			ast_channel_pbx_set(chan, control->pbx);
 			control->pbx = NULL;
-			return &FAIL;
+			return -1;
 		}
 
 		ast_assert(stasis_app_get_bridge(control) == NULL);
 		control->bridge = bridge;
 	}
-	return &OK;
+	return 0;
 }
 
 int stasis_app_control_add_channel_to_bridge(
 	struct stasis_app_control *control, struct ast_bridge *bridge)
 {
-	int *res;
 	ast_debug(3, "%s: Sending channel add_to_bridge command\n",
 			stasis_app_control_get_channel_id(control));
-	res = stasis_app_send_command(control,
-		app_control_add_channel_to_bridge, bridge);
-	return *res;
+
+	return app_send_command_on_condition(
+		control, app_control_add_channel_to_bridge, bridge,
+		app_control_can_add_channel_to_bridge);
 }
 
-static void *app_control_remove_channel_from_bridge(
+static int app_control_remove_channel_from_bridge(
 	struct stasis_app_control *control,
 	struct ast_channel *chan, void *data)
 {
 	struct ast_bridge *bridge = data;
 
 	if (!control) {
-		return &FAIL;
+		return -1;
 	}
 
 	/* We should only depart from our own bridge */
@@ -791,22 +920,21 @@ static void *app_control_remove_channel_from_bridge(
 		ast_log(LOG_WARNING, "%s: Not in bridge %s; not removing\n",
 			stasis_app_control_get_channel_id(control),
 			bridge->uniqueid);
-		return &FAIL;
+		return -1;
 	}
 
 	ast_bridge_depart(chan);
-	return &OK;
+	return 0;
 }
 
 int stasis_app_control_remove_channel_from_bridge(
 	struct stasis_app_control *control, struct ast_bridge *bridge)
 {
-	int *res;
 	ast_debug(3, "%s: Sending channel remove_from_bridge command\n",
 			stasis_app_control_get_channel_id(control));
-	res = stasis_app_send_command(control,
-		app_control_remove_channel_from_bridge, bridge);
-	return *res;
+	return app_send_command_on_condition(
+		control, app_control_remove_channel_from_bridge, bridge,
+		app_control_can_remove_channel_from_bridge);
 }
 
 const char *stasis_app_control_get_channel_id(