daemon/mmapped: use static_assert on undefined padding

CZ-NIC · Nov 4, 2024 · 53db552 · 53db552
1 parent 555afe8
commit 53db552
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Showing 2 changed files with 15 additions and 13 deletions.
diff --git a/daemon/defer.c b/daemon/defer.c
@@ -458,11 +458,12 @@ int defer_init(const char *mmap_file, int cpus)
 
 	size_t size = offsetof(struct defer, kru) + KRU.get_size(capacity_log);
 	size_t header_size = offsetof(struct defer, using_avx2) + sizeof(header.using_avx2);
-	kr_assert(header_size ==
-		sizeof(header.capacity) +
-		sizeof(header.max_decay) +
-		sizeof(header.cpus) +
-		sizeof(header.using_avx2));  // no undefined padding inside
+	static_assert(  // no padding up to .using_avx2
+		offsetof(struct defer, using_avx2) ==
+			sizeof(header.capacity) +
+			sizeof(header.max_decay) +
+			sizeof(header.cpus),
+		"detected padding with undefined data inside mmapped header");
 
 	ret = mmapped_init(&defer_mmapped, mmap_file, size, &header, header_size);
 	if (ret == MMAPPED_WAS_FIRST) {

diff --git a/daemon/ratelimiting.c b/daemon/ratelimiting.c
@@ -63,14 +63,15 @@ int ratelimiting_init(const char *mmap_file, size_t capacity, uint32_t instant_l
 	};
 
 	size_t header_size = offsetof(struct ratelimiting, using_avx2) + sizeof(header.using_avx2);
-	kr_assert(header_size ==
-		sizeof(header.capacity) +
-		sizeof(header.instant_limit) +
-		sizeof(header.rate_limit) +
-		sizeof(header.log_period) +
-		sizeof(header.slip) +
-		sizeof(header.dry_run) +
-		sizeof(header.using_avx2));  // no undefined padding inside
+	static_assert(  // no padding up to .using_avx2
+		offsetof(struct ratelimiting, using_avx2) ==
+			sizeof(header.capacity) +
+			sizeof(header.instant_limit) +
+			sizeof(header.rate_limit) +
+			sizeof(header.log_period) +
+			sizeof(header.slip) +
+			sizeof(header.dry_run),
+		"detected padding with undefined data inside mmapped header");
 
 	int ret = mmapped_init(&ratelimiting_mmapped, mmap_file, size, &header, header_size);
 	if (ret == MMAPPED_WAS_FIRST) {