cosmetic: use osmo_strlcpy() everywhere

Shorten some code and make obvious to the reader that the string copy is done
in a safe way.

Change-Id: I900726cf06d34128db22a3d3d911ee0d1423b1bd
diff --git a/openbsc/tests/gtphub/gtphub_test.c b/openbsc/tests/gtphub/gtphub_test.c
index 2b542dd..e7c27d2 100644
--- a/openbsc/tests/gtphub/gtphub_test.c
+++ b/openbsc/tests/gtphub/gtphub_test.c
@@ -437,21 +437,15 @@
 	       "  returning GGSN addr from imsi %s ni %s: %s\n",
 	       imsi_str, apn_ni_str, gtphub_port_str(pp));
 
-	if (imsi_str) {
-		strncpy(resolve_ggsn_got_imsi, imsi_str,
-			sizeof(resolve_ggsn_got_imsi));
-		resolve_ggsn_got_imsi[sizeof(resolve_ggsn_got_imsi) - 1] = '\0';
-	}
-	else
-		strcpy(resolve_ggsn_got_imsi, "(null)");
+	if (!imsi_str)
+		imsi_str = "(null)";
+	osmo_strlcpy(resolve_ggsn_got_imsi, imsi_str,
+		     sizeof(resolve_ggsn_got_imsi));
 
-	if (apn_ni_str) {
-		strncpy(resolve_ggsn_got_ni, apn_ni_str,
-			sizeof(resolve_ggsn_got_ni));
-		resolve_ggsn_got_ni[sizeof(resolve_ggsn_got_ni) - 1] = '\0';
-	}
-	else
-		strcpy(resolve_ggsn_got_ni, "(null)");
+	if (!apn_ni_str)
+		apn_ni_str = "(null)";
+	osmo_strlcpy(resolve_ggsn_got_ni, apn_ni_str,
+		     sizeof(resolve_ggsn_got_ni));
 
 	return pp;
 }