daemon/defer: fix linter warnings

Author: Lukáš Ondráček

daemon/defer.c

@@ -897,7 +897,10 @@ int defer_init(const char *mmap_file, uint32_t log_period, uint32_t hard_timeout
 	for (size_t i = 0; i < QUEUES_CNT; i++)
 		queue_init(queues[i]);
 
-	signal(SIGALRM, defer_alarm);
+	if (signal(SIGALRM, defer_alarm) == SIG_ERR) {
+		kr_log_error(DEFER, "Cannot set SIGALRM handler, interrupting of too long work on a single request will not work: %s\n",
+			strerror(errno));
+	}
 	defer_alarm(0);
 
 	return 0;

daemon/defer.h

@@ -127,7 +127,10 @@ static inline bool defer_sample_is_accounting(void)
 /// Start accounting work; optionally save state of current accounting.
 /// Current state can be saved only after having an address assigned.
 static inline void defer_sample_start(defer_sample_state_t *prev_state_out) {
-	if (!defer) return;
+	if (!defer) {
+		if (prev_state_out) *prev_state_out = (defer_sample_state_t){ 0 }; // just to meet undefined-value check of linter, but never used
+		return;
+	}
 	uint64_t stamp = defer_get_stamp();
 
 	// suspend

daemon/worker.c

@@ -2024,7 +2024,8 @@ static enum protolayer_event_cb_result pl_dns_stream_disconnected(
 		return PROTOLAYER_EVENT_PROPAGATE;
 
 	defer_sample_state_t defer_prev_sample_state;
-	if (session->outgoing)
+	const bool use_recursive_defer_sampling = session->outgoing; // make linter warning silent
+	if (use_recursive_defer_sampling)
 		defer_sample_start(&defer_prev_sample_state);
 
 	while (!session2_waitinglist_is_empty(session)) {
@@ -2043,7 +2044,7 @@ static enum protolayer_event_cb_result pl_dns_stream_disconnected(
 				qry->flags.TCP = false;
 			}
 			qr_task_step(task, NULL, NULL);
-			defer_sample_restart();
+			defer_sample_restart();  // use_recursive_defer_sampling == true
 		} else {
 			kr_assert(task->ctx->source.session == session);
 			task->ctx->source.session = NULL;
@@ -2068,7 +2069,7 @@ static enum protolayer_event_cb_result pl_dns_stream_disconnected(
 		worker_task_unref(task);
 	}
 
-	if (session->outgoing)
+	if (use_recursive_defer_sampling)
 		defer_sample_stop(&defer_prev_sample_state, true);
 
 	return PROTOLAYER_EVENT_PROPAGATE;