enable using api command data as c-string inplace

Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com>

src/event.c

@@ -165,7 +165,9 @@ int hyper_event_read(struct hyper_event *he, int efd)
 	}
 
 	fprintf(stdout, "get length %" PRIu32"\n", len);
-	if (len > buf->size) {
+	// test it with '>=' to leave at least one byte in handle(),
+	// so that handle() can convert the data to c-string inplace.
+	if (len >= buf->size) {
 		fprintf(stderr, "get length %" PRIu32", too long\n", len);
 		return -1;
 	}

src/init.c

@@ -1054,6 +1054,8 @@ static int hyper_channel_handle(struct hyper_event *de, uint32_t len)
 	uint8_t *data = NULL;
 	int i, ret = 0;
 
+	// append a null byte to it. hyper_event_read() left this room for us.
+	buf->data[buf->get] = 0;
 	for (i = 0; i < buf->get; i++)
 		fprintf(stdout, "%0x ", buf->data[i]);