From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Sat, 13 Mar 2021 09:02:20 +0000 (+0100)
Subject: lib/resolve *_LAYERS: detect bad return code from module
X-Git-Tag: v5.3.1~5^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e3e800889035fe5cdba95418bf892f285fde8724;p=thirdparty%2Fknot-resolver.git

lib/resolve *_LAYERS: detect bad return code from module

Practical example was now in dnstap (060349c9).  This way we detect
such mistakes more often and closer to their point of origin.
---

diff --git a/lib/resolve.c b/lib/resolve.c
index 521b97efb..8bfd69072 100644
--- a/lib/resolve.c
+++ b/lib/resolve.c
@@ -111,6 +111,12 @@ static int answer_finalize_yield(kr_layer_t *ctx) { return kr_ok(); }
 			struct kr_layer layer = {.state = (r)->state, .api = mod->layer, .req = (r)}; \
 			if (layer.api && layer.api->func) { \
 				(r)->state = layer.api->func(&layer, ##__VA_ARGS__); \
+				/* It's an easy mistake to return error code, for example. */ \
+				/* (though we could allow such an overload later) */ \
+				if (unlikely(!kr_state_consistent((r)->state))) { \
+					assert(!EINVAL); \
+					(r)->state = KR_STATE_FAIL; \
+				} else \
 				if ((r)->state == KR_STATE_YIELD) { \
 					func ## _yield(&layer, ##__VA_ARGS__); \
 					break; \