log: add easy way to log hex blobs.

Use it in one case, and also fix another logging FIXME.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

daemon/cryptopkt.c

@@ -495,8 +495,9 @@ static struct io_plan *keys_exchanged(struct io_conn *conn,
 			     neg->their_sessionpubkey,
 			     sizeof(neg->their_sessionpubkey),
 			     &sessionkey)) {
-		/* FIXME: Dump key in this case. */
-		log_unusual(neg->log, "Bad sessionkey");
+		log_unusual_blob(neg->log,  "Bad sessionkey %s",
+				 neg->their_sessionpubkey,
+				 sizeof(neg->their_sessionpubkey));
 		return io_close(conn);
 	}
 

daemon/log.c

@@ -359,6 +359,26 @@ void log_struct_(struct log *log, int level,
 	tal_free(ctx);
 }
 
+void log_blob_(struct log *log, enum log_level level, const char *fmt,
+	       size_t len, ...)
+{
+	va_list ap;
+	const void *blob;
+	const char *hex;
+
+	/* Macro wrappers ensure we only have one arg. */
+	va_start(ap, len);
+	blob = va_arg(ap, void *);
+	va_end(ap);
+
+	hex = tal_hexstr(log, blob, len);
+	if (level == -1)
+		log_add(log, fmt, hex);
+	else
+		log_(log, level, fmt, hex);
+	tal_free(hex);
+}
+
 void log_each_line_(const struct log_record *lr,
 		    void (*func)(unsigned int skipped,
 				 struct timerel time,

daemon/log.h

@@ -42,6 +42,22 @@ void log_(struct log *log, enum log_level level, const char *fmt, ...)
 void log_add(struct log *log, const char *fmt, ...) PRINTF_FMT(2,3);
 void logv(struct log *log, enum log_level level, const char *fmt, va_list ap);
 
+void log_blob_(struct log *log, enum log_level level, const char *fmt,
+	       size_t len, ...)
+	PRINTF_FMT(3,5);
+
+/* These must have %s where the blob is to go. */
+#define log_add_blob(log, fmt, blob, len)			\
+	log_blob_((log), -1, (fmt), (len), (char *)(blob))
+
+#define log_debug_blob(log, fmt, blob, len)			\
+	log_blob_((log), LOG_DBG, (fmt), (len), (char *)(blob))
+#define log_info_blob(log, fmt, blob, len)				\
+	log_blob_((log), LOG_INFORM, (fmt), (len), (char *)(blob))
+#define log_unusual_blob(log, fmt, blob, len)				\
+	log_blob_((log), LOG_UNUSUAL, (fmt), (len), (char *)(blob))
+#define log_broken_blob(log, fmt, blob, len)				\
+	log_blob_((log), LOG_BROKEN, (fmt), (len), (char *)(blob))
 
 /* Makes sure ptr is a 'structtype', makes sure it's in loggable_structs. */
 #define log_struct_check_(log, loglevel, fmt, structtype, ptr)		\

daemon/peer.c

@@ -3197,8 +3197,9 @@ static const struct bitcoin_tx *htlc_timeout_tx(const struct peer *peer,
 static void reset_onchain_closing(struct peer *peer)
 {
 	if (peer->onchain.tx) {
-		/* FIXME: Log old txid */
-		log_unusual(peer->log, "New anchor spend, forgetting old");
+		log_unusual_struct(peer->log,
+				   "New anchor spend, forgetting old tx %s",
+				   struct sha256_double, &peer->onchain.txid);
 		peer->onchain.tx = tal_free(peer->onchain.tx);
 		peer->onchain.resolved = NULL;
 		peer->onchain.htlcs = NULL;