TT#111150 Use localtime_r() instead of thread-unsafe localtime()

While the code is not threaded, better be future-proof and use safer
APIs, which in addition has less side-effects as it does not set the
global TZ related variables.

Also check for failures.

Change-Id: I083d2b5ad6901ac1a91d42d1ab7fe3e0989b02a0
Warned-by: lgtm

daemon/recording.c

@@ -456,16 +456,22 @@ static int rec_pcap_meta_finish_file(struct call *call) {
 	time_t start = call->created.tv_sec;
 	time_t end = rtpe_now.tv_sec;
 	char timebuffer[20];
-	struct tm *timeinfo;
+	struct tm timeinfo;
 	struct timeval *terminate;
 	terminate = &(((struct call_monologue *)call->monologues.head->data)->terminated);
 	fprintf(recording->u.pcap.meta_fp, "\nTimestamp terminated ms(first monologue): %.3lf", terminate->tv_sec*1000.0 + terminate->tv_usec/1000.0);
-	timeinfo = localtime(&start);
-	strftime(timebuffer, 20, "%FT%T", timeinfo);
-	fprintf(recording->u.pcap.meta_fp, "\n\ncall start time: %s\n", timebuffer);
-	timeinfo = localtime(&end);
-	strftime(timebuffer, 20, "%FT%T", timeinfo);
-	fprintf(recording->u.pcap.meta_fp, "call end time: %s\n", timebuffer);
+	if (localtime_r(&start, &timeinfo) < 0) {
+		ilog(LOG_ERROR, "Cannot get start local time, while cleaning up recording meta file: %s", strerror(errno));
+	} else {
+		strftime(timebuffer, 20, "%FT%T", &timeinfo);
+		fprintf(recording->u.pcap.meta_fp, "\n\ncall start time: %s\n", timebuffer);
+	}
+	if (localtime_r(&end, &timeinfo) < 0) {
+		ilog(LOG_ERROR, "Cannot get end local time, while cleaning up recording meta file: %s", strerror(errno));
+	} else {
+		strftime(timebuffer, 20, "%FT%T", &timeinfo);
+		fprintf(recording->u.pcap.meta_fp, "call end time: %s\n", timebuffer);
+	}
 
 	// Print metadata
 	if (call->metadata.len)