voicecall: Throttle emulators

Make sure that only a single request from (possibly multiple) emulators
is ever sent to the voicecall driver.  In the beginning it wasn't clear
whether this will be necessary, however several command implementations
already implemented basic throttling (+CHUP, ATD, CHLD=3, CHLD=2x) and
it made sense to make this more formal.

The other constraint is the abrupt removal of the emulator atom while an
operation is pending.  This case must be handled gracefully.  See next
commit.

1 files changed, 45 insertions, 35 deletions

diff --git a/src/voicecall.c b/src/voicecall.c
index f6d15ff7..241b38ea 100644
--- a/src/voicecall.c
+++ b/src/voicecall.c
@@ -48,15 +48,9 @@
 
 GSList *g_drivers = NULL;
 
-struct multi_release {
-	ofono_voicecall_cb_t cb;
-	void *data;
-};
-
 struct ofono_voicecall {
 	GSList *call_list;
 	GSList *release_list;
-	struct multi_release multi_release;
 	GSList *multiparty_list;
 	GHashTable *en_list; /* emergency number list */
 	GSList *sim_en_list; /* Emergency numbers already read from SIM */
@@ -77,6 +71,7 @@ struct ofono_voicecall {
 	unsigned int hfp_watch;
 	GKeyFile *settings;
 	char *imsi;
+	ofono_voicecall_cb_t release_queue_done_cb;
 	struct ofono_emulator *pending_em;
 	unsigned int pending_id;
 	char *em_atd_number;
@@ -1219,7 +1214,8 @@ static void voicecalls_emit_call_added(struct ofono_voicecall *vc,
 	g_dbus_send_message(ofono_dbus_get_connection(), signal);
 }
 
-static void voicecalls_release_queue(struct ofono_voicecall *vc, GSList *calls)
+static void voicecalls_release_queue(struct ofono_voicecall *vc, GSList *calls,
+					ofono_voicecall_cb_t cb)
 {
 	GSList *l;
 	struct voicecall *call;
@@ -1235,6 +1231,8 @@ static void voicecalls_release_queue(struct ofono_voicecall *vc, GSList *calls)
 
 		vc->release_list = g_slist_prepend(vc->release_list, l->data);
 	}
+
+	vc->release_queue_done_cb = cb;
 }
 
 static void voicecalls_release_next(struct ofono_voicecall *vc)
@@ -1696,9 +1694,8 @@ static DBusMessage *manager_hangup_all(DBusConnection *conn,
 	vc->pending = dbus_message_ref(msg);
 
 	if (vc->driver->hangup_all == NULL) {
-		voicecalls_release_queue(vc, vc->call_list);
-		vc->multi_release.cb = voicecalls_release_done;
-		vc->multi_release.data = vc;
+		voicecalls_release_queue(vc, vc->call_list,
+						voicecalls_release_done);
 		voicecalls_release_next(vc);
 	} else
 		vc->driver->hangup_all(vc, generic_callback, vc);
@@ -1950,9 +1947,8 @@ static DBusMessage *multiparty_hangup(DBusConnection *conn,
 	}
 
 	/* Fall back to the old-fashioned way */
-	voicecalls_release_queue(vc, vc->multiparty_list);
-	vc->multi_release.cb = voicecalls_release_done;
-	vc->multi_release.data = vc;
+	voicecalls_release_queue(vc, vc->multiparty_list,
+					voicecalls_release_done);
 	voicecalls_release_next(vc);
 
 out:
@@ -2263,7 +2259,7 @@ static void multirelease_callback(const struct ofono_error *error, void *data)
 		return;
 	}
 
-	vc->multi_release.cb(error, vc->multi_release.data);
+	vc->release_queue_done_cb(error, vc);
 }
 
 static void emit_en_list_changed(struct ofono_voicecall *vc)
@@ -2706,9 +2702,10 @@ static void sim_watch(struct ofono_atom *atom,
 
 static void emulator_generic_cb(const struct ofono_error *error, void *data)
 {
-	struct ofono_emulator *em = data;
+	struct ofono_voicecall *vc = data;
 
-	ofono_emulator_send_final(em, error);
+	ofono_emulator_send_final(vc->pending_em, error);
+	vc->pending_em = NULL;
 }
 
 static void emulator_mpty_join_cb(const struct ofono_error *error, void *data)
@@ -2781,8 +2778,16 @@ static void emulator_mpty_private_chat_cb(const struct ofono_error *error,
 	g_slist_free(old);
 }
 
+#define CHECK_BUSY(vc, em, result)				\
+	if (vc->pending || vc->dial_req || vc->pending_em) {	\
+		result.error = 126;				\
+		result.type = OFONO_ERROR_TYPE_CME;		\
+		ofono_emulator_send_final(em, &result);		\
+	}							\
+
 static void emulator_ata_cb(struct ofono_emulator *em,
-			struct ofono_emulator_request *req, void *userdata)
+				struct ofono_emulator_request *req,
+				void *userdata)
 {
 	struct ofono_voicecall *vc = userdata;
 	struct ofono_error result;
@@ -2791,13 +2796,16 @@ static void emulator_ata_cb(struct ofono_emulator *em,
 
 	switch (ofono_emulator_request_get_type(req)) {
 	case OFONO_EMULATOR_REQUEST_TYPE_COMMAND_ONLY:
+		CHECK_BUSY(vc, em, result)
+
 		if (!voicecalls_have_incoming(vc))
 			goto fail;
 
 		if (vc->driver->answer == NULL)
 			goto fail;
 
-		vc->driver->answer(vc, emulator_generic_cb, em);
+		vc->pending_em = em;
+		vc->driver->answer(vc, emulator_generic_cb, vc);
 		break;
 
 	default:
@@ -2819,7 +2827,7 @@ static void emulator_chup_cb(struct ofono_emulator *em,
 
 	switch (ofono_emulator_request_get_type(req)) {
 	case OFONO_EMULATOR_REQUEST_TYPE_COMMAND_ONLY:
-		if (vc->release_list)
+		if (vc->pending || vc->pending_em)
 			goto fail;
 
 		if (vc->driver->release_specific == NULL &&
@@ -2827,7 +2835,8 @@ static void emulator_chup_cb(struct ofono_emulator *em,
 			goto fail;
 
 		if (vc->driver->hangup_active) {
-			vc->driver->hangup_active(vc, emulator_generic_cb, em);
+			vc->pending_em = em;
+			vc->driver->hangup_active(vc, emulator_generic_cb, vc);
 			goto done;
 		}
 
@@ -2845,8 +2854,8 @@ static void emulator_chup_cb(struct ofono_emulator *em,
 		if (vc->release_list == NULL)
 			goto fail;
 
-		vc->multi_release.cb = emulator_generic_cb;
-		vc->multi_release.data = em;
+		vc->pending_em = em;
+		vc->release_queue_done_cb = emulator_generic_cb;
 		voicecalls_release_next(vc);
 
 done:
@@ -2939,6 +2948,8 @@ static void emulator_chld_cb(struct ofono_emulator *em,
 		if (!ofono_emulator_request_next_number(req, &chld))
 			goto fail;
 
+		CHECK_BUSY(vc, em, result)
+
 		switch (chld) {
 		case 0:
 			if (vc->driver->set_udub == NULL)
@@ -2947,42 +2958,42 @@ static void emulator_chld_cb(struct ofono_emulator *em,
 			if (vc->driver->release_all_held == NULL)
 				goto fail;
 
+			vc->pending_em = em;
+
 			if (voicecalls_have_waiting(vc)) {
 				vc->driver->set_udub(vc,
-						emulator_generic_cb, em);
+						emulator_generic_cb, vc);
 				return;
 			}
 
 			vc->driver->release_all_held(vc,
-					emulator_generic_cb, em);
+					emulator_generic_cb, vc);
 			return;
 		case 1:
 			if (vc->driver->release_all_active == NULL)
 				goto fail;
 
+			vc->pending_em = em;
 			vc->driver->release_all_active(vc,
-					emulator_generic_cb, em);
+					emulator_generic_cb, vc);
 			return;
 		case 2:
 			if (vc->driver->hold_all_active == NULL)
 				goto fail;
 
+			vc->pending_em = em;
 			vc->driver->hold_all_active(vc,
-					emulator_generic_cb, em);
+					emulator_generic_cb, vc);
 			return;
 		case 3:
 			if (vc->driver->create_multiparty == NULL)
 				goto fail;
 
-			if (vc->pending_em || vc->pending || vc->dial_req)
-				goto fail;
-
 			if (!voicecalls_have_held(vc) ||
 					!voicecalls_have_active(vc))
 				goto fail;
 
 			vc->pending_em = em;
-
 			vc->driver->create_multiparty(vc,
 					emulator_mpty_join_cb, vc);
 			return;
@@ -2990,8 +3001,9 @@ static void emulator_chld_cb(struct ofono_emulator *em,
 			if (vc->driver->transfer == NULL)
 				goto fail;
 
+			vc->pending_em = em;
 			vc->driver->transfer(vc,
-					emulator_generic_cb, em);
+					emulator_generic_cb, vc);
 			return;
 		default:
 			break;
@@ -3001,8 +3013,9 @@ static void emulator_chld_cb(struct ofono_emulator *em,
 			if (vc->driver->release_specific == NULL)
 				goto fail;
 
+			vc->pending_em = em;
 			vc->driver->release_specific(vc, chld - 10,
-					emulator_generic_cb, em);
+						emulator_generic_cb, vc);
 			return;
 		}
 
@@ -3013,9 +3026,6 @@ static void emulator_chld_cb(struct ofono_emulator *em,
 			if (vc->driver->private_chat == NULL)
 				goto fail;
 
-			if (vc->pending_em || vc->pending || vc->dial_req)
-				goto fail;
-
 			for (l = vc->multiparty_list; l; l = l->next) {
 				struct voicecall *v = l->data;
 				if (v->call->id == id)