4612. [bug] Silence 'may be use uninitalised' warning and simplify

                        the code in lwres/getaddinfo:process_answer.
                        [RT #45158]

CHANGES

+4612.	[bug]		Silence 'may be use uninitalised' warning and simplify
+			the code in lwres/getaddinfo:process_answer.
+			[RT #45158]
+
 4611.	[bug]		The default LMDB mapsize was too low and caused
 			errors after few thousand zones were added using
 			rndc addzone. A new config option "lmdb-mapsize"

lib/irs/getaddrinfo.c

@@ -681,6 +681,7 @@ process_answer(isc_task_t *task, isc_event_t *event) {
 	dns_clientresevent_t *rev = (dns_clientresevent_t *)event;
 	dns_rdatatype_t qtype;
 	dns_name_t *name;
+	isc_boolean_t wantcname;
 
 	REQUIRE(trans != NULL);
 	resstate = trans->resstate;
@@ -724,14 +725,26 @@ process_answer(isc_task_t *task, isc_event_t *event) {
 		goto done;
 	}
 
+	wantcname = ISC_TF((resstate->head->ai_flags & AI_CANONNAME) != 0);
+
 	/* Parse the response and construct the addrinfo chain */
 	for (name = ISC_LIST_HEAD(rev->answerlist); name != NULL;
 	     name = ISC_LIST_NEXT(name, link)) {
 		isc_result_t result;
 		dns_rdataset_t *rdataset;
-		isc_buffer_t b;
-		isc_region_t r;
-		char t[1024];
+		char cname[1024];
+
+		if (wantcname) {
+			isc_buffer_t b;
+
+			isc_buffer_init(&b, cname, sizeof(cname));
+			result = dns_name_totext(name, ISC_TRUE, &b);
+			if (result != ISC_R_SUCCESS) {
+				error = EAI_FAIL;
+				goto done;
+			}
+			isc_buffer_putuint8(&b, '\0');
+		}
 
 		for (rdataset = ISC_LIST_HEAD(name->list);
 		     rdataset != NULL;
@@ -741,17 +754,6 @@ process_answer(isc_task_t *task, isc_event_t *event) {
 			if (rdataset->type != qtype)
 				continue;
 
-			if ((resstate->head->ai_flags & AI_CANONNAME) != 0) {
-				isc_buffer_init(&b, t, sizeof(t));
-				result = dns_name_totext(name, ISC_TRUE, &b);
-				if (result != ISC_R_SUCCESS) {
-					error = EAI_FAIL;
-					goto done;
-				}
-				isc_buffer_putuint8(&b, '\0');
-				isc_buffer_usedregion(&b, &r);
-			}
-
 			for (result = dns_rdataset_first(rdataset);
 			     result == ISC_R_SUCCESS;
 			     result = dns_rdataset_next(rdataset)) {
@@ -780,7 +782,8 @@ process_answer(isc_task_t *task, isc_event_t *event) {
 				switch (family) {
 				case AF_INET:
 					dns_rdataset_current(rdataset, &rdata);
-					result = dns_rdata_tostruct(&rdata, &rdata_a,
+					result = dns_rdata_tostruct(&rdata,
+								    &rdata_a,
 								    NULL);
 					RUNTIME_CHECK(result == ISC_R_SUCCESS);
 					SIN(ai->ai_addr)->sin_port =
@@ -791,7 +794,8 @@ process_answer(isc_task_t *task, isc_event_t *event) {
 					break;
 				case AF_INET6:
 					dns_rdataset_current(rdataset, &rdata);
-					result = dns_rdata_tostruct(&rdata, &rdata_aaaa,
+					result = dns_rdata_tostruct(&rdata,
+								    &rdata_aaaa,
 								    NULL);
 					RUNTIME_CHECK(result == ISC_R_SUCCESS);
 					SIN6(ai->ai_addr)->sin6_port =
@@ -802,10 +806,8 @@ process_answer(isc_task_t *task, isc_event_t *event) {
 					break;
 				}
 
-				if ((resstate->head->ai_flags & AI_CANONNAME)
-				    != 0) {
-					ai->ai_canonname =
-						strdup((const char *)r.base);
+				if (wantcname) {
+					ai->ai_canonname = strdup(cname);
 					if (ai->ai_canonname == NULL) {
 						error = EAI_MEMORY;
 						goto done;