From fbd2e47f519ab1d6edbd4b9b50a1cebff31217e9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@sury.org>
Date: Mon, 4 Jun 2018 13:41:09 +0200
Subject: [PATCH] Add small tweaks to the code to fix compilation when ISC
 assertions are disabled

While implementing the new unit testing framework cmocka, it was found that the
BIND 9 code doesn't compile when assertions are disabled or replaced with any
function (such as mock_assert() from cmocka unit testing framework) that's not
directly recognized as assertion by the compiler.

This made the compiler to complain about blocks of code that was recognized as
unreachable before, but now it isn't.

The changes in this commit include:

* assigns default values to couple of local variables,
* moves some return statements around INSIST assertions,
* adds __builtin_unreachable(); annotations after some INSIST assertions,
* fixes one broken assertion (= instead of ==)
---
 bin/dig/dighost.c             |  2 +-
 bin/named/server.c            | 12 ++++++------
 bin/named/zoneconf.c          |  2 +-
 bin/tests/system/rpz/dnsrps.c |  6 ++++--
 config.h.in                   |  3 +++
 configure                     | 32 ++++++++++++++++++++++++++++++++
 configure.ac                  | 15 +++++++++++++++
 lib/dns/dnstap.c              |  1 +
 lib/dns/iptable.c             |  2 +-
 lib/dns/master.c              |  5 +++--
 lib/dns/rpz.c                 |  7 ++++---
 lib/isc/include/isc/util.h    |  6 ++++++
 lib/isc/pk11.c                |  1 +
 lib/isc/random.c              |  2 +-
 lib/ns/client.c               |  2 +-
 lib/ns/query.c                |  2 +-
 16 files changed, 81 insertions(+), 19 deletions(-)

diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index 416a3eaa5c..daf7a923dd 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -2291,7 +2291,7 @@ setup_lookup(dig_lookup_t *lookup) {
 
 		if (lookup->ecs_addr != NULL) {
 			uint8_t addr[16];
-			uint16_t family;
+			uint16_t family = 0;
 			uint32_t plen;
 			struct sockaddr *sa;
 			struct sockaddr_in *sin;
diff --git a/bin/named/server.c b/bin/named/server.c
index 4f14900f7f..93924b2afe 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -2718,7 +2718,7 @@ catz_create_chg_task(dns_catz_entry_t *entry, dns_catz_zone_t *origin,
 	catz_chgzone_event_t *event;
 	isc_task_t *task;
 	isc_result_t result;
-	isc_taskaction_t action;
+	isc_taskaction_t action = NULL;
 
 	switch (type) {
 	case DNS_EVENT_CATZADDZONE:
@@ -4356,7 +4356,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist,
 		obj2 = cfg_tuple_get(obj, "response");
 		if (!cfg_obj_isvoid(obj2)) {
 			const char *resp = cfg_obj_asstring(obj2);
-			isc_result_t r;
+			isc_result_t r = DNS_R_SERVFAIL;
 
 			if (strcasecmp(resp, "drop") == 0)
 				r = DNS_R_DROP;
@@ -5036,7 +5036,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist,
 	obj2 = cfg_tuple_get(obj, "response");
 	if (!cfg_obj_isvoid(obj2)) {
 		const char *resp = cfg_obj_asstring(obj2);
-		isc_result_t r;
+		isc_result_t r = DNS_R_SERVFAIL;
 
 		if (strcasecmp(resp, "drop") == 0)
 			r = DNS_R_DROP;
@@ -5281,7 +5281,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist,
 		const char *empty_dbtype[4] =
 				    { "_builtin", "empty", NULL, NULL };
 		int empty_dbtypec = 4;
-		dns_zonestat_level_t statlevel;
+		dns_zonestat_level_t statlevel = dns_zonestat_none;
 
 		name = dns_fixedname_initname(&fixed);
 
@@ -9920,7 +9920,7 @@ static void
 named_server_reload(isc_task_t *task, isc_event_t *event) {
 	named_server_t *server = (named_server_t *)event->ev_arg;
 
-	INSIST(task = server->task);
+	INSIST(task == server->task);
 	UNUSED(task);
 
 	isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
@@ -12586,7 +12586,7 @@ newzone_parse(named_server_t *server, char *command, dns_view_t **viewp,
 	const char *viewname = NULL;
 	dns_rdataclass_t rdclass;
 	dns_view_t *view = NULL;
-	const char *bn;
+	const char *bn = NULL;
 
 	REQUIRE(viewp != NULL && *viewp == NULL);
 	REQUIRE(zoneobjp != NULL && *zoneobjp == NULL);
diff --git a/bin/named/zoneconf.c b/bin/named/zoneconf.c
index 52264239e0..f01004a8ba 100644
--- a/bin/named/zoneconf.c
+++ b/bin/named/zoneconf.c
@@ -903,7 +903,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 	const dns_master_style_t *masterstyle = &dns_master_style_default;
 	isc_stats_t *zoneqrystats;
 	dns_stats_t *rcvquerystats;
-	dns_zonestat_level_t statlevel;
+	dns_zonestat_level_t statlevel = dns_zonestat_none;
 	int seconds;
 	dns_zone_t *mayberaw = (raw != NULL) ? raw : zone;
 	isc_dscp_t dscp;
diff --git a/bin/tests/system/rpz/dnsrps.c b/bin/tests/system/rpz/dnsrps.c
index 06da69144d..0ad3add41a 100644
--- a/bin/tests/system/rpz/dnsrps.c
+++ b/bin/tests/system/rpz/dnsrps.c
@@ -82,10 +82,11 @@ main(int argc, char **argv) {
 			}
 #ifdef USE_DNSRPS
 			printf("%s\n", librpz->dnsrpzd_path);
-			return (0);
 #else
 			INSIST(0);
+			ISC_UNREACHABLE();
 #endif
+			return (0);
 
 		case 'n':
 			if (!link_dnsrps(&emsg)) {
@@ -132,10 +133,11 @@ main(int argc, char **argv) {
 			librpz->rsp_detach(&rsp);
 			librpz->client_detach(&client);
 			printf("%u\n", serial);
-			return (0);
 #else
 			INSIST(0);
+			ISC_UNREACHABLE();
 #endif
+			return (0);
 
 		case 'w':
 			seconds = strtod(optarg, &p);
diff --git a/config.h.in b/config.h.in
index 8fccd17b65..0ac0deb2f7 100644
--- a/config.h.in
+++ b/config.h.in
@@ -60,6 +60,9 @@
 /* Define to 1 if the compiler supports __builtin_expect. */
 #undef HAVE_BUILTIN_EXPECT
 
+/* define if the compiler supports __builtin_unreachable(). */
+#undef HAVE_BUILTIN_UNREACHABLE
+
 /* Define to 1 if you have the `catgets' function. */
 #undef HAVE_CATGETS
 
diff --git a/configure b/configure
index 90cffa9ec4..5576d75ccb 100755
--- a/configure
+++ b/configure
@@ -18161,6 +18161,38 @@ fi
 done
 
 
+#
+# Check for __builtin_unreachable
+#
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking compiler support for __builtin_unreachable()" >&5
+$as_echo_n "checking compiler support for __builtin_unreachable()... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+__builtin_unreachable();
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+
+$as_echo "#define HAVE_BUILTIN_UNREACHABLE 1" >>confdefs.h
+
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+
 #
 # Check for __builtin_expect
 #
diff --git a/configure.ac b/configure.ac
index d100ae29ac..55e65150bd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2017,6 +2017,21 @@ LIBS="$LIBS $ISC_ATOMIC_LIBS"
 
 AC_CHECK_HEADERS([uchar.h])
 
+#
+# Check for __builtin_unreachable
+#
+AC_MSG_CHECKING([compiler support for __builtin_unreachable()])
+AC_LINK_IFELSE(
+  [AC_LANG_PROGRAM(
+     [[]],
+     [[__builtin_unreachable();]]
+   )],
+  [AC_MSG_RESULT([yes])
+   AC_DEFINE([HAVE_BUILTIN_UNREACHABLE], [1], [define if the compiler supports __builtin_unreachable().])
+  ],
+  [AC_MSG_RESULT([no])
+  ])
+
 #
 # Check for __builtin_expect
 #
diff --git a/lib/dns/dnstap.c b/lib/dns/dnstap.c
index b9b26580d6..3368d90105 100644
--- a/lib/dns/dnstap.c
+++ b/lib/dns/dnstap.c
@@ -700,6 +700,7 @@ dnstap_type(dns_dtmsgtype_t msgtype) {
 		return (DNSTAP__MESSAGE__TYPE__UPDATE_RESPONSE);
 	default:
 		INSIST(0);
+		ISC_UNREACHABLE();
 	}
 }
 
diff --git a/lib/dns/iptable.c b/lib/dns/iptable.c
index 36bad9bf58..c4e3b0d06f 100644
--- a/lib/dns/iptable.c
+++ b/lib/dns/iptable.c
@@ -67,7 +67,7 @@ dns_iptable_addprefix(dns_iptable_t *tab, const isc_netaddr_t *addr,
 	int i;
 
 	INSIST(DNS_IPTABLE_VALID(tab));
-	INSIST(tab->radix);
+	INSIST(tab->radix != NULL);
 
 	NETADDR_TO_PREFIX_T(addr, pfx, bitlen);
 
diff --git a/lib/dns/master.c b/lib/dns/master.c
index c4025832cf..8b39beca3b 100644
--- a/lib/dns/master.c
+++ b/lib/dns/master.c
@@ -549,8 +549,6 @@ loadctx_create(dns_masterformat_t format, isc_mem_t *mctx,
 
 	lctx->format = format;
 	switch (format) {
-	default:
-		INSIST(0);
 	case dns_masterformat_text:
 		lctx->openfile = openfile_text;
 		lctx->load = load_text;
@@ -563,6 +561,9 @@ loadctx_create(dns_masterformat_t format, isc_mem_t *mctx,
 		lctx->openfile = openfile_map;
 		lctx->load = load_map;
 		break;
+	default:
+		INSIST(0);
+		ISC_UNREACHABLE();
 	}
 
 	if (lex != NULL) {
diff --git a/lib/dns/rpz.c b/lib/dns/rpz.c
index 00751923e2..7a70ce2b4d 100644
--- a/lib/dns/rpz.c
+++ b/lib/dns/rpz.c
@@ -567,8 +567,8 @@ adj_trigger_cnt(dns_rpz_zones_t *rpzs, dns_rpz_num_t rpz_num,
 		const dns_rpz_cidr_key_t *tgt_ip, dns_rpz_prefix_t tgt_prefix,
 		bool inc)
 {
-	dns_rpz_trigger_counter_t *cnt;
-	dns_rpz_zbits_t *have;
+	dns_rpz_trigger_counter_t *cnt = 0;
+	dns_rpz_zbits_t *have = 0;
 
 	switch (rpz_type) {
 	case DNS_RPZ_TYPE_CLIENT_IP:
@@ -611,6 +611,7 @@ adj_trigger_cnt(dns_rpz_zones_t *rpzs, dns_rpz_num_t rpz_num,
 		break;
 	default:
 		INSIST(0);
+		ISC_UNREACHABLE();
 	}
 
 	if (inc) {
@@ -2477,7 +2478,7 @@ dns_rpz_find_ip(dns_rpz_zones_t *rpzs, dns_rpz_type_t rpz_type,
 	dns_rpz_addr_zbits_t tgt_set;
 	dns_rpz_cidr_node_t *found;
 	isc_result_t result;
-	dns_rpz_num_t rpz_num;
+	dns_rpz_num_t rpz_num = 0;
 	dns_rpz_have_t have;
 	int i;
 
diff --git a/lib/isc/include/isc/util.h b/lib/isc/include/isc/util.h
index 2343bebd97..6c5c32dee4 100644
--- a/lib/isc/include/isc/util.h
+++ b/lib/isc/include/isc/util.h
@@ -203,6 +203,12 @@
  */
 #include <isc/likely.h>
 
+#ifdef HAVE_BUILTIN_UNREACHABLE
+#define ISC_UNREACHABLE() __builtin_unreachable();
+#else
+#define ISC_UNREACHABLE()
+#endif
+
 #ifdef UNIT_TESTING
 extern void mock_assert(const int result, const char* const expression,
 			const char * const file, const int line);
diff --git a/lib/isc/pk11.c b/lib/isc/pk11.c
index 6b77ed9fea..c405e61608 100644
--- a/lib/isc/pk11.c
+++ b/lib/isc/pk11.c
@@ -667,6 +667,7 @@ pk11_numbits(CK_BYTE_PTR data, unsigned int bytecnt) {
 		break;
 	}
 	INSIST(0);
+	ISC_UNREACHABLE();
 }
 
 CK_ATTRIBUTE *
diff --git a/lib/isc/random.c b/lib/isc/random.c
index c682cbc3f7..54a60a072e 100644
--- a/lib/isc/random.c
+++ b/lib/isc/random.c
@@ -114,7 +114,7 @@ isc_random_buf(void *buf, size_t buflen) {
 	int i;
 	uint32_t r;
 
-	REQUIRE(buf);
+	REQUIRE(buf != NULL);
 	REQUIRE(buflen > 0);
 
 	RUNTIME_CHECK(isc_once_do(&isc_random_once,
diff --git a/lib/ns/client.c b/lib/ns/client.c
index 7df2336c1b..6a8d208498 100644
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -1686,7 +1686,7 @@ ns_client_addopt(ns_client_t *client, dns_message_t *message,
 		isc_buffer_t buf;
 		uint8_t addr[16];
 		uint32_t plen, addrl;
-		uint16_t family;
+		uint16_t family = 0;
 
 		/* Add CLIENT-SUBNET option. */
 
diff --git a/lib/ns/query.c b/lib/ns/query.c
index 937da5d68e..71aa3824d9 100644
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -2587,7 +2587,7 @@ rpz_get_zbits(ns_client_t *client,
 	      dns_rdatatype_t ip_type, dns_rpz_type_t rpz_type)
 {
 	dns_rpz_st_t *st;
-	dns_rpz_zbits_t zbits;
+	dns_rpz_zbits_t zbits = 0;
 
 	REQUIRE(client != NULL);
 	REQUIRE(client->query.rpz_st != NULL);