daemon: add helper to log hex.

Good for keys; eventually we'll want to log structures by type though.

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

daemon/log.c

@@ -262,6 +262,13 @@ void log_add(struct log *log, const char *fmt, ...)
 	va_end(ap);
 }
 
+void log_add_hex(struct log *log, const void *data, size_t len)
+{
+	char hex[hex_str_size(len)];
+	hex_encode(data, len, hex, hex_str_size(len));
+	log_add(log, "%s", hex);
+}
+
 void log_each_line_(const struct log_record *lr,
 		    void (*func)(unsigned int skipped,
 				 struct timerel time,

daemon/log.h

@@ -39,6 +39,7 @@ void log_io(struct log *log, bool in, const void *data, size_t len);
 void log_(struct log *log, enum log_level level, const char *fmt, ...)
 	PRINTF_FMT(3,4);
 void log_add(struct log *log, const char *fmt, ...) PRINTF_FMT(2,3);
+void log_add_hex(struct log *log, const void *data, size_t len);
 void logv(struct log *log, enum log_level level, const char *fmt, va_list ap);
 
 #define log_add_struct(log, structtype, ptr)				\