flock implemented

src/main.c

@@ -171,15 +171,19 @@ static void *display_thread(void *arg) {
 }
 
 int main(void) {
-	control.g_running = true;
-	applog(LOG_START, "linuxSmartie started");
+	applog(LOG_START, "linuxSmartie starting");
 	applog(LOG_DBG, "Compiled on %s %s with %s", __DATE__, __TIME__, C_STD);
-	struct sensors_t *sensors = malloc(sizeof(*sensors)); // no actual point in mallocing and it is ever so sligtly slower to access heap vs stack, but its cool
 
+	/* see if another instance is up, quit if it is */
+	if (get_instance_lock() < 0)
+		return 1;
+
+	/* malloc memory for the struct */
+	struct sensors_t *sensors = malloc(sizeof(*sensors)); // no actual point in mallocing and it is ever so sligtly slower to access heap vs stack, but its cool
 	if (sensors == NULL) {
 		applog(LOG_ERR, "can't allocate mem for the sensor struct. You don't got %lu bytes bro?", sizeof(struct sensors_t));
 		free(sensors);
-		return -1;
+		return 2;
 	}
 	applog(LOG_INF, "sensor struct allocated, size is %lu bytes", sizeof(struct sensors_t));
 
@@ -196,6 +200,7 @@ int main(void) {
 	/* control vars setup */
 	pthread_mutex_init(&control.sensors_mtx, NULL);
 	pthread_cond_init(&control.sensors_ready, NULL);
+	control.g_running = true;
 
 	/* thread setup */
 	pthread_t sensors_pthread;