Merge branch 'master' into rtpmidi

22 files changed, 68 insertions, 272 deletions

diff --git a/backends/artnet.c b/backends/artnet.c
index e01f038..b181296 100644
--- a/backends/artnet.c
+++ b/backends/artnet.c
@@ -381,28 +381,15 @@ static int artnet_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int artnet_start(){
-	size_t n, u, p;
+static int artnet_start(size_t n, instance** inst){
+	size_t u, p;
 	int rv = 1;
-	instance** inst = NULL;
 	artnet_instance_data* data = NULL;
 	artnet_instance_id id = {
 		.label = 0
 	};
 
-	//fetch all defined instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	if(!artnet_fds){
-		free(inst);
 		fprintf(stderr, "Failed to start ArtNet backend: no descriptors bound\n");
 		return 1;
 	}
@@ -448,22 +435,15 @@ static int artnet_start(){
 
 	rv = 0;
 bail:
-	free(inst);
 	return rv;
 }
 
-static int artnet_shutdown(){
-	size_t n, p;
-	instance** inst = NULL;
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
+static int artnet_shutdown(size_t n, instance** inst){
+	size_t p;
 
 	for(p = 0; p < n; p++){
 		free(inst[p]->impl);
 	}
-	free(inst);
 
 	for(p = 0; p < artnet_fds; p++){
 		close(artnet_fd[p].fd);
diff --git a/backends/artnet.h b/backends/artnet.h
index f6a6709..59bd53f 100644
--- a/backends/artnet.h
+++ b/backends/artnet.h
@@ -10,8 +10,8 @@ static instance* artnet_instance();
 static channel* artnet_channel(instance* instance, char* spec, uint8_t flags);
 static int artnet_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int artnet_handle(size_t num, managed_fd* fds);
-static int artnet_start();
-static int artnet_shutdown();
+static int artnet_start(size_t n, instance** inst);
+static int artnet_shutdown(size_t n, instance** inst);
 
 #define ARTNET_PORT "6454"
 #define ARTNET_VERSION 14
diff --git a/backends/evdev.c b/backends/evdev.c
index 0da5ae6..d2eeba8 100644
--- a/backends/evdev.c
+++ b/backends/evdev.c
@@ -393,21 +393,10 @@ static int evdev_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int evdev_start(){
-	size_t n, u, fds = 0;
-	instance** inst = NULL;
+static int evdev_start(size_t n, instance** inst){
+	size_t u, fds = 0;
 	evdev_instance_data* data = NULL;
 
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (evdev_instance_data*) inst[u]->impl;
 
@@ -415,7 +404,6 @@ static int evdev_start(){
 		if(data->output_enabled){
 			if(libevdev_uinput_create_from_device(data->output_proto, LIBEVDEV_UINPUT_OPEN_MANAGED, &data->output_ev)){
 				fprintf(stderr, "Failed to create evdev output device: %s\n", strerror(errno));
-				free(inst);
 				return 1;
 			}
 			fprintf(stderr, "Created device node %s for instance %s\n", libevdev_uinput_get_devnode(data->output_ev), inst[u]->name);
@@ -426,7 +414,6 @@ static int evdev_start(){
 		if(data->input_fd >= 0){
 			if(mm_manage_fd(data->input_fd, BACKEND_NAME, 1, inst[u])){
 				fprintf(stderr, "Failed to register event input descriptor for instance %s\n", inst[u]->name);
-				free(inst);
 				return 1;
 			}
 			fds++;
@@ -439,7 +426,6 @@ static int evdev_start(){
 	}
 
 	fprintf(stderr, "evdev backend registered %zu descriptors to core\n", fds);
-	free(inst);
 	return 0;
 }
 
@@ -512,18 +498,12 @@ static int evdev_set(instance* inst, size_t num, channel** c, channel_value* v)
 #endif
 }
 
-static int evdev_shutdown(){
+static int evdev_shutdown(size_t n, instance** inst){
 	evdev_instance_data* data = NULL;
-	instance** instances = NULL;
-	size_t n, u;
-
-	if(mm_backend_instances(BACKEND_NAME, &n, &instances)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
+	size_t u;
 
 	for(u = 0; u < n; u++){
-		data = (evdev_instance_data*) instances[u]->impl;
+		data = (evdev_instance_data*) inst[u]->impl;
 
 		if(data->input_fd >= 0){
 			libevdev_free(data->input_ev);
@@ -542,7 +522,6 @@ static int evdev_shutdown(){
 		free(data);
 	}
 
-	free(instances);
 	fprintf(stderr, "evdev backend shut down\n");
 	return 0;
 }
diff --git a/backends/evdev.h b/backends/evdev.h
index 6504416..0c877fc 100644
--- a/backends/evdev.h
+++ b/backends/evdev.h
@@ -15,8 +15,8 @@ static instance* evdev_instance();
 static channel* evdev_channel(instance* instance, char* spec, uint8_t flags);
 static int evdev_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int evdev_handle(size_t num, managed_fd* fds);
-static int evdev_start();
-static int evdev_shutdown();
+static int evdev_start(size_t n, instance** inst);
+static int evdev_shutdown(size_t n, instance** inst);
 
 #define INPUT_NODES "/dev/input"
 #define INPUT_PREFIX "event"
diff --git a/backends/jack.c b/backends/jack.c
index e7bed04..eb53190 100644
--- a/backends/jack.c
+++ b/backends/jack.c
@@ -593,10 +593,9 @@ static int mmjack_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int mmjack_start(){
+static int mmjack_start(size_t n, instance** inst){
 	int rv = 1, feedback_fd[2];
-	size_t n, u, p;
-	instance** inst = NULL;
+	size_t u, p;
 	pthread_mutexattr_t mutex_attr;
 	mmjack_instance_data* data = NULL;
 	jack_status_t error;
@@ -618,12 +617,6 @@ static int mmjack_start(){
 		goto bail;
 	}
 
-	//fetch all instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		goto bail;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (mmjack_instance_data*) inst[u]->impl;
 
@@ -689,20 +682,13 @@ static int mmjack_start(){
 	rv = 0;
 bail:
 	pthread_mutexattr_destroy(&mutex_attr);
-	free(inst);
 	return rv;
 }
 
-static int mmjack_shutdown(){
-	size_t n, u, p;
-	instance** inst = NULL;
+static int mmjack_shutdown(size_t n, instance** inst){
+	size_t u, p;
 	mmjack_instance_data* data = NULL;
 
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (mmjack_instance_data*) inst[u]->impl;
 
@@ -741,8 +727,6 @@ static int mmjack_shutdown(){
 		data->fd = -1;
 	}
 
-	free(inst);
-
 	fprintf(stderr, "jack backend shut down\n");
 	return 0;
 }
diff --git a/backends/jack.h b/backends/jack.h
index a7f3e8b..66c66db 100644
--- a/backends/jack.h
+++ b/backends/jack.h
@@ -9,8 +9,8 @@ static instance* mmjack_instance();
 static channel* mmjack_channel(instance* inst, char* spec, uint8_t flags);
 static int mmjack_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int mmjack_handle(size_t num, managed_fd* fds);
-static int mmjack_start();
-static int mmjack_shutdown();
+static int mmjack_start(size_t n, instance** inst);
+static int mmjack_shutdown(size_t n, instance** inst);
 
 #define JACK_DEFAULT_CLIENT_NAME "MIDIMonster"
 #define JACK_DEFAULT_SERVER_NAME "default"
diff --git a/backends/loopback.c b/backends/loopback.c
index 41e6f85..c2c3430 100644
--- a/backends/loopback.c
+++ b/backends/loopback.c
@@ -92,20 +92,14 @@ static int loopback_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int loopback_start(){
+static int loopback_start(size_t n, instance** inst){
 	return 0;
 }
 
-static int loopback_shutdown(){
-	size_t n, u, p;
-	instance** inst = NULL;
+static int loopback_shutdown(size_t n, instance** inst){
+	size_t u, p;
 	loopback_instance_data* data = NULL;
 
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (loopback_instance_data*) inst[u]->impl;
 		for(p = 0; p < data->n; p++){
@@ -115,8 +109,6 @@ static int loopback_shutdown(){
 		free(inst[u]->impl);
 	}
 
-	free(inst);
-
 	fprintf(stderr, "Loopback backend shut down\n");
 	return 0;
 }
diff --git a/backends/loopback.h b/backends/loopback.h
index ee51c66..c508d72 100644
--- a/backends/loopback.h
+++ b/backends/loopback.h
@@ -7,8 +7,8 @@ static instance* loopback_instance();
 static channel* loopback_channel(instance* inst, char* spec, uint8_t flags);
 static int loopback_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int loopback_handle(size_t num, managed_fd* fds);
-static int loopback_start();
-static int loopback_shutdown();
+static int loopback_start(size_t n, instance** inst);
+static int loopback_shutdown(size_t n, instance** inst);
 
 typedef struct /*_loopback_instance_data*/ {
 	size_t n;
diff --git a/backends/lua.c b/backends/lua.c
index 40e6613..2ce40f5 100644
--- a/backends/lua.c
+++ b/backends/lua.c
@@ -428,17 +428,10 @@ static int lua_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int lua_start(){
-	size_t n, u, p;
-	instance** inst = NULL;
+static int lua_start(size_t n, instance** inst){
+	size_t u, p;
 	lua_instance_data* data = NULL;
 
-	//fetch all defined instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	//resolve channels to their handler functions
 	for(u = 0; u < n; u++){
 		data = (lua_instance_data*) inst[u]->impl;
@@ -457,8 +450,6 @@ static int lua_start(){
 		}
 	}
 
-	free(inst);
-
 	#ifdef MMBACKEND_LUA_TIMERFD
 	//register the timer with the core
 	fprintf(stderr, "Lua backend registering 1 descriptor to core\n");
@@ -469,17 +460,10 @@ static int lua_start(){
 	return 0;
 }
 
-static int lua_shutdown(){
-	size_t n, u, p;
-	instance** inst = NULL;
+static int lua_shutdown(size_t n, instance** inst){
+	size_t u, p;
 	lua_instance_data* data = NULL;
 
-	//fetch all instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (lua_instance_data*) inst[u]->impl;
 		//stop the interpreter
@@ -495,7 +479,6 @@ static int lua_shutdown(){
 		free(inst[u]->impl);
 	}
 
-	free(inst);
 	//free module-global data
 	free(timer);
 	timer = NULL;
diff --git a/backends/lua.h b/backends/lua.h
index 4ea5b0a..75f03c4 100644
--- a/backends/lua.h
+++ b/backends/lua.h
@@ -16,8 +16,8 @@ static instance* lua_instance();
 static channel* lua_channel(instance* inst, char* spec, uint8_t flags);
 static int lua_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int lua_handle(size_t num, managed_fd* fds);
-static int lua_start();
-static int lua_shutdown();
+static int lua_start(size_t n, instance** inst);
+static int lua_shutdown(size_t n, instance** inst);
 #ifndef MMBACKEND_LUA_TIMERFD
 static uint32_t lua_interval();
 #endif
diff --git a/backends/maweb.c b/backends/maweb.c
index d008cc0..8cf201e 100644
--- a/backends/maweb.c
+++ b/backends/maweb.c
@@ -989,17 +989,10 @@ static int maweb_handle(size_t num, managed_fd* fds){
 	return rv;
 }
 
-static int maweb_start(){
-	size_t n, u, p;
-	instance** inst = NULL;
+static int maweb_start(size_t n, instance** inst){
+	size_t u, p;
 	maweb_instance_data* data = NULL;
 
-	//fetch all defined instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		//sort channels
 		data = (maweb_instance_data*) inst[u]->impl;
@@ -1017,11 +1010,6 @@ static int maweb_start(){
 		}
 	}
 
-	free(inst);
-	if(!n){
-		return 0;
-	}
-
 	fprintf(stderr, "maweb backend registering %" PRIsize_t " descriptors to core\n", n);
 
 	//initialize timeouts
@@ -1029,17 +1017,10 @@ static int maweb_start(){
 	return 0;
 }
 
-static int maweb_shutdown(){
-	size_t n, u;
-	instance** inst = NULL;
+static int maweb_shutdown(size_t n, instance** inst){
+	size_t u;
 	maweb_instance_data* data = NULL;
 
-	//fetch all instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (maweb_instance_data*) inst[u]->impl;
 		free(data->host);
@@ -1065,8 +1046,6 @@ static int maweb_shutdown(){
 		data->channels = 0;
 	}
 
-	free(inst);
-
 	fprintf(stderr, "maweb backend shut down\n");
 	return 0;
 }
diff --git a/backends/maweb.h b/backends/maweb.h
index 05095f8..50b777a 100644
--- a/backends/maweb.h
+++ b/backends/maweb.h
@@ -7,8 +7,8 @@ static instance* maweb_instance();
 static channel* maweb_channel(instance* inst, char* spec, uint8_t flags);
 static int maweb_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int maweb_handle(size_t num, managed_fd* fds);
-static int maweb_start();
-static int maweb_shutdown();
+static int maweb_start(size_t n, instance** inst);
+static int maweb_shutdown(size_t n, instance** inst);
 static uint32_t maweb_interval();
 
 //Default login password: MD5("midimonster")
diff --git a/backends/midi.c b/backends/midi.c
index 92776ca..2088774 100644
--- a/backends/midi.c
+++ b/backends/midi.c
@@ -338,25 +338,13 @@ static int midi_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int midi_start(){
-	size_t n = 0, p;
+static int midi_start(size_t n, instance** inst){
+	size_t p;
 	int nfds, rv = 1;
 	struct pollfd* pfds = NULL;
-	instance** inst = NULL;
 	midi_instance_data* data = NULL;
 	snd_seq_addr_t addr;
 
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
-	//if there are no ports, do nothing
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	//connect to the sequencer
 	if(snd_seq_open(&sequencer, "default", SND_SEQ_OPEN_DUPLEX, 0) < 0){
 		fprintf(stderr, "Failed to open ALSA sequencer\n");
@@ -424,18 +412,12 @@ static int midi_start(){
 
 bail:
 	free(pfds);
-	free(inst);
 	return rv;
 }
 
-static int midi_shutdown(){
-	size_t n, p;
-	instance** inst = NULL;
+static int midi_shutdown(size_t n, instance** inst){
+	size_t p;
 	midi_instance_data* data = NULL;
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
 
 	for(p = 0; p < n; p++){
 		data = (midi_instance_data*) inst[p]->impl;
@@ -445,7 +427,6 @@ static int midi_shutdown(){
 		data->write = NULL;
 		free(inst[p]->impl);
 	}
-	free(inst);
 
 	//close midi
 	if(sequencer){
diff --git a/backends/midi.h b/backends/midi.h
index 4e16f90..66a02bc 100644
--- a/backends/midi.h
+++ b/backends/midi.h
@@ -7,8 +7,8 @@ static instance* midi_instance();
 static channel* midi_channel(instance* instance, char* spec, uint8_t flags);
 static int midi_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int midi_handle(size_t num, managed_fd* fds);
-static int midi_start();
-static int midi_shutdown();
+static int midi_start(size_t n, instance** inst);
+static int midi_shutdown(size_t n, instance** inst);
 
 typedef struct /*_midi_instance_data*/ {
 	int port;
diff --git a/backends/ola.cpp b/backends/ola.cpp
index c13e8f9..fd121a0 100644
--- a/backends/ola.cpp
+++ b/backends/ola.cpp
@@ -220,9 +220,8 @@ static void ola_register_callback(const std::string &error) {
 	}
 }
 
-static int ola_start(){
-	size_t n, u, p;
-	instance** inst = NULL;
+static int ola_start(size_t n, instance** inst){
+	size_t u, p;
 	ola_instance_data* data = NULL;
 
 	ola_select = new ola::io::SelectServer();
@@ -249,18 +248,6 @@ static int ola_start(){
 
 	ola_client->SetDmxCallback(ola::NewCallback(&ola_data_receive));
 
-	//fetch all defined instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		goto bail;
-	}
-
-	//this should not happen anymore (backends without instances are not started anymore)
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (ola_instance_data*) inst[u]->impl;
 		inst[u]->ident = data->universe_id;
@@ -277,10 +264,8 @@ static int ola_start(){
 
 	//run the ola select implementation to run all commands
 	ola_select->RunOnce();
-	free(inst);
 	return 0;
 bail:
-	free(inst);
 	delete ola_client;
 	ola_client = NULL;
 	delete ola_select;
@@ -288,18 +273,12 @@ bail:
 	return 1;
 }
 
-static int ola_shutdown(){
-	size_t n, p;
-	instance** inst = NULL;
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
+static int ola_shutdown(size_t n, instance** inst){
+	size_t p;
 
 	for(p = 0; p < n; p++){
 		free(inst[p]->impl);
 	}
-	free(inst);
 
 	if(ola_client){
 		ola_client->Stop();
diff --git a/backends/ola.h b/backends/ola.h
index 0c42bac..083e971 100644
--- a/backends/ola.h
+++ b/backends/ola.h
@@ -11,8 +11,8 @@ extern "C" {
 	static channel* ola_channel(instance* instance, char* spec, uint8_t flags);
 	static int ola_set(instance* inst, size_t num, channel** c, channel_value* v);
 	static int ola_handle(size_t num, managed_fd* fds);
-	static int ola_start();
-	static int ola_shutdown();
+	static int ola_start(size_t n, instance** inst);
+	static int ola_shutdown(size_t n, instance** inst);
 }
 
 #define MAP_COARSE 0x0200
diff --git a/backends/osc.c b/backends/osc.c
index 757ad89..2c65ecb 100644
--- a/backends/osc.c
+++ b/backends/osc.c
@@ -522,6 +522,7 @@ static int osc_configure_instance(instance* inst, char* option, char* value){
 			return 1;
 		}
 
+		//this requests a socket with SO_BROADCAST set, whether this is useful functionality for OSC is up for debate
 		data->fd = mmbackend_socket(host, port, SOCK_DGRAM, 1, 1);
 		if(data->fd < 0){
 			fprintf(stderr, "Failed to bind for instance %s\n", inst->name);
@@ -891,22 +892,10 @@ static int osc_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int osc_start(){
-	size_t n, u, fds = 0;
-	instance** inst = NULL;
+static int osc_start(size_t n, instance** inst){
+	size_t u, fds = 0;
 	osc_instance_data* data = NULL;
 
-	//fetch all instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	//update instance identifiers
 	for(u = 0; u < n; u++){
 		data = (osc_instance_data*) inst[u]->impl;
@@ -915,7 +904,6 @@ static int osc_start(){
 			inst[u]->ident = data->fd;
 			if(mm_manage_fd(data->fd, BACKEND_NAME, 1, inst[u])){
 				fprintf(stderr, "Failed to register OSC descriptor for instance %s\n", inst[u]->name);
-				free(inst);
 				return 1;
 			}
 			fds++;
@@ -926,21 +914,13 @@ static int osc_start(){
 	}
 
 	fprintf(stderr, "OSC backend registered %" PRIsize_t " descriptors to core\n", fds);
-
-	free(inst);
 	return 0;
 }
 
-static int osc_shutdown(){
-	size_t n, u, c;
-	instance** inst = NULL;
+static int osc_shutdown(size_t n, instance** inst){
+	size_t u, c;
 	osc_instance_data* data = NULL;
 
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (osc_instance_data*) inst[u]->impl;
 		for(c = 0; c < data->channels; c++){
@@ -967,7 +947,6 @@ static int osc_shutdown(){
 		free(inst[u]->impl);
 	}
 
-	free(inst);
 	fprintf(stderr, "OSC backend shut down\n");
 	return 0;
 }
diff --git a/backends/osc.h b/backends/osc.h
index 6f3b923..f8ff3ff 100644
--- a/backends/osc.h
+++ b/backends/osc.h
@@ -14,8 +14,8 @@ static instance* osc_instance();
 static channel* osc_map_channel(instance* inst, char* spec, uint8_t flags);
 static int osc_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int osc_handle(size_t num, managed_fd* fds);
-static int osc_start();
-static int osc_shutdown();
+static int osc_start(size_t n, instance** inst);
+static int osc_shutdown(size_t n, instance** inst);
 
 typedef enum {
 	not_set = 0,
diff --git a/backends/sacn.c b/backends/sacn.c
index edb648d..ef422e8 100644
--- a/backends/sacn.c
+++ b/backends/sacn.c
@@ -171,6 +171,7 @@ static int sacn_configure_instance(instance* inst, char* option, char* value){
 	}
 	else if(!strcmp(option, "unicast")){
 		data->unicast_input = strtoul(value, NULL, 10);
+		return 0;
 	}
 
 	fprintf(stderr, "Unknown configuration option %s for sACN backend\n", option);
@@ -530,10 +531,9 @@ static int sacn_handle(size_t num, managed_fd* fds){
 	return 0;
 }
 
-static int sacn_start(){
-	size_t n, u, p;
+static int sacn_start(size_t n, instance** inst){
+	size_t u, p;
 	int rv = 1;
-	instance** inst = NULL;
 	sacn_instance_data* data = NULL;
 	sacn_instance_id id = {
 		.label = 0
@@ -543,17 +543,6 @@ static int sacn_start(){
 	};
 	struct sockaddr_in* dest_v4 = NULL;
 
-	//fetch all instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	if(!global_cfg.fds){
 		fprintf(stderr, "Failed to start sACN backend: no descriptors bound\n");
 		free(inst);
@@ -624,23 +613,15 @@ static int sacn_start(){
 
 	rv = 0;
 bail:
-	free(inst);
 	return rv;
 }
 
-static int sacn_shutdown(){
-	size_t n, p;
-	instance** inst = NULL;
-
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
+static int sacn_shutdown(size_t n, instance** inst){
+	size_t p;
 
 	for(p = 0; p < n; p++){
 		free(inst[p]->impl);
 	}
-	free(inst);
 
 	for(p = 0; p < global_cfg.fds; p++){
 		close(global_cfg.fd[p].fd);
diff --git a/backends/sacn.h b/backends/sacn.h
index 1d3268c..726fa68 100644
--- a/backends/sacn.h
+++ b/backends/sacn.h
@@ -7,8 +7,8 @@ static instance* sacn_instance();
 static channel* sacn_channel(instance* instance, char* spec, uint8_t flags);
 static int sacn_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int sacn_handle(size_t num, managed_fd* fds);
-static int sacn_start();
-static int sacn_shutdown();
+static int sacn_start(size_t n, instance** inst);
+static int sacn_shutdown(size_t n, instance** inst);
 
 #define SACN_PORT "5568"
 #define SACN_RECV_BUF 8192
diff --git a/backends/winmidi.c b/backends/winmidi.c
index 790257b..090e438 100644
--- a/backends/winmidi.c
+++ b/backends/winmidi.c
@@ -440,10 +440,9 @@ static int winmidi_match_output(char* prefix){
 	return -1;
 }
 
-static int winmidi_start(){
-	size_t n = 0, p;
+static int winmidi_start(size_t n, instance** inst){
+	size_t p;
 	int device, rv = -1;
-	instance** inst = NULL;
 	winmidi_instance_data* data = NULL;
 	struct sockaddr_storage sockadd = {
 		0
@@ -453,18 +452,6 @@ static int winmidi_start(){
 	char* error = NULL;
 	DBGPF("winmidi main thread ID is %ld\n", GetCurrentThreadId());
 
-	//fetch all instances
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
-	//no instances, we're done
-	if(!n){
-		free(inst);
-		return 0;
-	}
-
 	//output device list if requested
 	if(backend_config.list_devices){
 		winmidi_match_input(NULL);
@@ -552,20 +539,13 @@ static int winmidi_start(){
 
 	rv = 0;
 bail:
-	free(inst);
 	return rv;
 }
 
-static int winmidi_shutdown(){
-	size_t n, u;
-	instance** inst = NULL;
+static int winmidi_shutdown(size_t n, instance** inst){
+	size_t u;
 	winmidi_instance_data* data = NULL;
 
-	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
-		fprintf(stderr, "Failed to fetch instance list\n");
-		return 1;
-	}
-
 	for(u = 0; u < n; u++){
 		data = (winmidi_instance_data*) inst[u]->impl;
 		free(data->read);
@@ -586,7 +566,6 @@ static int winmidi_shutdown(){
 		}
 	}
 
-	free(inst);
 	closesocket(backend_config.socket_pair[0]);
 	closesocket(backend_config.socket_pair[1]);
 
diff --git a/backends/winmidi.h b/backends/winmidi.h
index 985c46a..81e7439 100644
--- a/backends/winmidi.h
+++ b/backends/winmidi.h
@@ -7,8 +7,8 @@ static instance* winmidi_instance();
 static channel* winmidi_channel(instance* inst, char* spec, uint8_t flags);
 static int winmidi_set(instance* inst, size_t num, channel** c, channel_value* v);
 static int winmidi_handle(size_t num, managed_fd* fds);
-static int winmidi_start();
-static int winmidi_shutdown();
+static int winmidi_start(size_t n, instance** inst);
+static int winmidi_shutdown(size_t n, instance** inst);
 
 typedef struct /*_winmidi_instance_data*/ {
 	char* read;