Silence Clang-Tidy

This commit makes lots of changes to the C code to appease the
Clang-Tidy linter. Some of the less obvious ones are due to C's weird
semantics regarding handling of numeric literals.

We also disable a bunch of the detections because they are
super-pedantic, arguably useless, or we have our own unwritten coding
style rules that solve the issues.

3 files changed, 30 insertions, 22 deletions

diff --git a/modules/dnstap/dnstap.c b/modules/dnstap/dnstap.c
index 75726672..07780fcb 100644
--- a/modules/dnstap/dnstap.c
+++ b/modules/dnstap/dnstap.c
@@ -193,6 +193,7 @@ static int dnstap_log(kr_layer_t *ctx, enum dnstap_log_phase phase) {
 				m.socket_family = DNSTAP__SOCKET_FAMILY__INET6;
 				m.has_socket_family = true;
 				break;
+			default:;
 		}
 	}
 
diff --git a/modules/hints/hints.c b/modules/hints/hints.c
index a3f2f300..af05ee24 100644
--- a/modules/hints/hints.c
+++ b/modules/hints/hints.c
@@ -194,9 +194,11 @@ static const knot_dname_t * raw_addr2reverse(const uint8_t *raw_addr, int family
 	#undef REV_MAXLEN
 
 	if (family == AF_INET) {
-		snprintf(reverse_addr, sizeof(reverse_addr),
-			 "%d.%d.%d.%d.in-addr.arpa.",
-		         raw_addr[3], raw_addr[2], raw_addr[1], raw_addr[0]);
+		int ret = snprintf(reverse_addr, sizeof(reverse_addr),
+				"%d.%d.%d.%d.in-addr.arpa.",
+				raw_addr[3], raw_addr[2], raw_addr[1], raw_addr[0]);
+		if (kr_fails_assert(ret > 0 && ret <= sizeof(reverse_addr)))
+			return NULL;
 	} else if (family == AF_INET6) {
 		char *ra_it = reverse_addr;
 		for (int i = 15; i >= 0; --i) {
@@ -262,7 +264,10 @@ static int add_reverse_pair(struct kr_zonecut *hints, const char *name, const ch
 		return kr_error(EINVAL);
 	}
 
-	return kr_zonecut_add(hints, key, ptr_name, knot_dname_size(ptr_name));
+	size_t dname_size = knot_dname_size(ptr_name);
+	if (kr_fails_assert(dname_size < INT_MAX))
+		return kr_error(EINVAL);
+	return kr_zonecut_add(hints, key, ptr_name, (int)dname_size);
 }
 
 /** For a given name, remove either one address or all of them (if == NULL).
@@ -276,7 +281,9 @@ static int del_pair(struct hints_data *data, const char *name, const char *addr)
 	if (!knot_dname_from_str(key, name, sizeof(key))) {
 		return kr_error(EINVAL);
 	}
-	int key_len = knot_dname_size(key);
+	size_t key_len = knot_dname_size(key);
+	if (kr_fails_assert(key_len <= INT_MAX))
+		return kr_error(EINVAL);
 
         if (addr) {
 		/* Remove the pair. */
@@ -286,7 +293,7 @@ static int del_pair(struct hints_data *data, const char *name, const char *addr)
 		}
 
 		const knot_dname_t *reverse_key = addr2reverse(addr);
-		kr_zonecut_del(&data->reverse_hints, reverse_key, key, key_len);
+		kr_zonecut_del(&data->reverse_hints, reverse_key, key, (int)key_len);
 		return kr_zonecut_del(&data->hints, key,
 					kr_inaddr(&ia.ip), kr_inaddr_len(&ia.ip));
 	}
@@ -306,7 +313,7 @@ static int del_pair(struct hints_data *data, const char *name, const char *addr)
 				? AF_INET : AF_INET6;
 		const knot_dname_t *reverse_key = raw_addr2reverse(addr_val, family);
 		if (reverse_key != NULL) {
-			kr_zonecut_del(&data->reverse_hints, reverse_key, key, key_len);
+			kr_zonecut_del(&data->reverse_hints, reverse_key, key, (int)key_len);
 		}
 	}
 
diff --git a/modules/stats/stats.c b/modules/stats/stats.c
index ebb28778..129023f8 100644
--- a/modules/stats/stats.c
+++ b/modules/stats/stats.c
@@ -116,7 +116,7 @@ static inline int collect_key(char *key, const knot_dname_t *name, uint16_t type
 	if (key_len < 0) {
 		return kr_error(key_len);
 	}
-	return key_len + sizeof(type);
+	return key_len + (int)sizeof(type);
 }
 
 static void collect_sample(struct stat_data *data, struct kr_rplan *rplan)
@@ -313,26 +313,26 @@ static char* stats_get(void *env, struct kr_module *module, const char *args)
 	struct stat_data *data = module->data;
 
 	/* Expecting CHAR_BIT to be 8, this is a safe bet */
-	char *ret = malloc(3 * sizeof(size_t) + 2);
-	if (!ret) {
-		return NULL;
-	}
+	char *str_value = NULL;
+	int ret = 0;
 
 	/* Check if it exists in const map. */
 	for (unsigned i = 0; i < metric_const_end; ++i) {
 		if (strcmp(const_metrics[i].key, args) == 0) {
-			sprintf(ret, "%zu", const_metrics[i].val);
-			return ret;
+			ret = asprintf(&str_value, "%zu", const_metrics[i].val);
+			if (ret < 0)
+				return NULL;
+			return str_value;
 		}
 	}
 	/* Check in variable map */
 	trie_val_t *val = trie_get_try(data->trie, args, strlen(args));
-	if (!val) {
-		free(ret);
+	if (!val)
 		return NULL;
-	}
-	sprintf(ret, "%zu", (size_t) *val);
-	return ret;
+	ret = asprintf(&str_value, "%zu", (size_t) *val);
+	if (ret < 0)
+		return NULL;
+	return str_value;
 }
 
 /** Checks whether:
@@ -356,9 +356,9 @@ static int list_entry(const char *key, uint32_t key_len, trie_val_t *val, void *
 	struct list_entry_context *ctx = baton;
 	if (!key_matches_prefix(key, key_len, ctx->key_prefix, ctx->key_prefix_len))
 		return 0;
-	size_t number = (size_t) *val;
+	size_t number = (size_t)*val;
 	auto_free char *key_nt = strndup(key, key_len);
-	json_append_member(ctx->root, key_nt, json_mknumber(number));
+	json_append_member(ctx->root, key_nt, json_mknumber((double)number));
 	return 0;
 }
 
@@ -375,7 +375,7 @@ static char* stats_list(void *env, struct kr_module *module, const char *args)
 	for (unsigned i = 0; i < metric_const_end; ++i) {
 		struct const_metric_elm *elm = &const_metrics[i];
 		if (!args || strncmp(elm->key, args, args_len) == 0) {
-			json_append_member(root, elm->key, json_mknumber(elm->val));
+			json_append_member(root, elm->key, json_mknumber((double)elm->val));
 		}
 	}
 	struct list_entry_context ctx = {