--- a/lib/dns/rdata/generic/loc_29.c	2018-09-04 00:04:41.000000000 -0400
+++ b/lib/dns/rdata/generic/loc_291.c	2019-04-18 00:09:34.927000000 -0400
@@ -454,11 +454,12 @@ totext_loc(ARGS_TOTEXT) {
 	isc_boolean_t east;
 	isc_boolean_t below;
 	isc_region_t sr;
-	char buf[sizeof("89 59 59.999 N 179 59 59.999 E "
-			"-42849672.95m 90000000m 90000000m 90000000m")];
 	char sbuf[sizeof("90000000m")];
 	char hbuf[sizeof("90000000m")];
 	char vbuf[sizeof("90000000m")];
+        /* "89 59 59.999 N 179 59 59.999 E " */
+        /* "-42849672.95m 90000000m 90000000m 90000000m"; */
+        char buf[8*6 + 12*1 + 2*10 + sizeof(sbuf)+sizeof(hbuf)+sizeof(vbuf)];
 	unsigned char size, hp, vp;
 	unsigned long poweroften[8] = { 1, 10, 100, 1000,
 					10000, 100000, 1000000, 10000000 };
@@ -550,7 +551,7 @@ totext_loc(ARGS_TOTEXT) {
 		altitude -= 10000000;
 	}
 
-	snprintf(buf, sizeof(buf),
+	snprintf(NULL, 0,
 		 "%d %d %d.%03d %s %d %d %d.%03d %s %s%lu.%02lum %s %s %s",
 		 d1, m1, s1, fs1, north ? "N" : "S",
 		 d2, m2, s2, fs2, east ? "E" : "W",
--- a/lib/dns/rdata/in_1/dhcid_49.c	2018-09-04 00:04:41.000000000 -0400
+++ b/lib/dns/rdata/in_1/dhcid_491.c	2019-04-18 00:12:14.143000000 -0400
@@ -35,9 +35,8 @@ fromtext_in_dhcid(ARGS_FROMTEXT) {
 static inline isc_result_t
 totext_in_dhcid(ARGS_TOTEXT) {
 	isc_region_t sr, sr2;
-	char buf[sizeof(" ; 64000 255 64000")];
-	size_t n;
-
+        /* " ; 64000 255 64000" */
+        char buf[5 + 3*5 + 1];
 	REQUIRE(rdata->type == dns_rdatatype_dhcid);
 	REQUIRE(rdata->rdclass == dns_rdataclass_in);
 	REQUIRE(rdata->length != 0);
@@ -55,10 +54,9 @@ totext_in_dhcid(ARGS_TOTEXT) {
 	if ((tctx->flags & DNS_STYLEFLAG_MULTILINE) != 0) {
 		RETERR(str_totext(/* ( */ " )", target));
 		if (rdata->length > 2) {
-			n = snprintf(buf, sizeof(buf), " ; %u %u %u",
+			snprintf(NULL, 0, " ; %u %u %u",
 				     sr2.base[0] * 256U + sr2.base[1],
 				     sr2.base[2], rdata->length - 3U);
-			INSIST(n < sizeof(buf));
 			RETERR(str_totext(buf, target));
 		}
 	}