Fix Coverity Scan issues.

511427
1431133
1436823
1436837
1436838
1436929

client/pub_shared.c

@@ -109,7 +109,7 @@ int load_file(const char *filename)
 		cfg.message = NULL;
 		cfg.msglen = 0;
 		return 0;
-	}else if(cfg.msglen < 0){
+	}else if(flen < 0){
 		fclose(fptr);
 		err_printf(&cfg, "Error: Unable to determine size of file \"%s\".\n", filename);
 		return 1;

src/bridge.c

@@ -399,8 +399,8 @@ int bridge__connect(struct mosquitto *context)
 			if (!context->bridge->notifications_local_only) {
 				notification_payload = '0';
 				rc = will__set(context, notification_topic, 1, &notification_payload, 1, true, NULL);
-				mosquitto__free(notification_topic);
 				if(rc != MOSQ_ERR_SUCCESS){
+					mosquitto__free(notification_topic);
 					return rc;
 				}
 			}

src/mosquitto.c

@@ -303,7 +303,7 @@ int listeners__start(struct mosquitto__listener_sock **listensock, int *listenso
 		if(listeners__start_local_only(listensock, listensock_count)){
 			db__close();
 			if(db.config->pid_file){
-				remove(db.config->pid_file);
+				(void)remove(db.config->pid_file);
 			}
 			return 1;
 		}
@@ -315,7 +315,7 @@ int listeners__start(struct mosquitto__listener_sock **listensock, int *listenso
 			if(listeners__start_single_mqtt(listensock, listensock_count, &listensock_index, &db.config->listeners[i])){
 				db__close();
 				if(db.config->pid_file){
-					remove(db.config->pid_file);
+					(void)remove(db.config->pid_file);
 				}
 				return 1;
 			}

src/net.c

@@ -649,7 +649,11 @@ static int net__socket_listen_tcp(struct mosquitto__listener *listener)
 #endif
 #ifdef IPV6_V6ONLY
 		ss_opt = 1;
-		setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &ss_opt, sizeof(ss_opt));
+		if(setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &ss_opt, sizeof(ss_opt)) < 0){
+			log__printf(NULL, MOSQ_LOG_WARNING,
+					"Warning when setting listener IPv6 mode: %s.\n",
+					strerror(errno));
+		}
 #endif
 
 		if(net__socket_nonblock(&sock)){

src/subs.c

@@ -246,10 +246,11 @@ static int sub__add_shared(struct mosquitto *context, uint8_t qos, uint32_t iden
 		for(i=0; i<context->shared_sub_count; i++){
 			if(!context->shared_subs[i]){
 				context->shared_subs[i] = shared_ref;
+				shared_ref = NULL;
 				break;
 			}
 		}
-		if(i == context->shared_sub_count){
+		if(shared_ref){
 			shared_subs = mosquitto__realloc(context->shared_subs, sizeof(struct mosquitto__subhier_ref *)*(size_t)(context->shared_sub_count + 1));
 			if(!shared_subs){
 				mosquitto__free(shared_ref);