FS-7761 [core] fix shutdown races running api commands during shutdown

src/switch_loadable_module.c

@@ -2070,8 +2070,8 @@ SWITCH_DECLARE(switch_codec_interface_t *) switch_loadable_module_get_codec_inte
 
 #define HASH_FUNC(_kind_) SWITCH_DECLARE(switch_##_kind_##_interface_t *) switch_loadable_module_get_##_kind_##_interface(const char *name)	\
 	{																	\
-		switch_##_kind_##_interface_t *i;								\
-		if ((i = switch_core_hash_find_locked(loadable_modules._kind_##_hash, name, loadable_modules.mutex))) {	\
+		switch_##_kind_##_interface_t *i = NULL;								\
+		if (loadable_modules._kind_##_hash && (i = switch_core_hash_find_locked(loadable_modules._kind_##_hash, name, loadable_modules.mutex))) {	\
 			PROTECT_INTERFACE(i);										\
 		}																\
 		return i;														\

src/switch_time.c

@@ -1362,7 +1362,11 @@ SWITCH_DECLARE(const char *) switch_lookup_timezone(const char *tz_name)
 {
 	char *value = NULL;
 
-	if (tz_name && (value = switch_core_hash_find(TIMEZONES_LIST.hash, tz_name)) == NULL) {
+	if (zstr(tz_name) || !TIMEZONES_LIST.hash) {
+		return NULL;
+	}
+	
+	if ((value = switch_core_hash_find(TIMEZONES_LIST.hash, tz_name)) == NULL) {
 		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Timezone '%s' not found!\n", tz_name);
 	}