diff --git a/compositor/compositor-wayland.c b/compositor/compositor-wayland.c
index c64944c2..98c675bd 100644
--- a/compositor/compositor-wayland.c
+++ b/compositor/compositor-wayland.c
@@ -513,7 +513,7 @@ wayland_compositor_create(struct wl_display *display, int width, int height)
 	struct wayland_compositor *c;
 	struct wl_event_loop *loop;
 	int fd;
-	char *socket_name;
+	char *socket_name, *env;
 	int socket_name_size;
 
 	c = malloc(sizeof *c);
@@ -522,8 +522,8 @@ wayland_compositor_create(struct wl_display *display, int width, int height)
 
 	memset(c, 0, sizeof *c);
 
-	socket_name_size = 1 + asprintf(&socket_name, "%c%s", '\0',
-					getenv("WAYLAND_DISPLAY"));
+	env = getenv("WAYLAND_DISPLAY");
+	socket_name_size = asprintf(&socket_name, "%c%s", '\0', env) + 1;
 
 	c->parent.display = wl_display_connect(socket_name, socket_name_size);
 	free(socket_name);
diff --git a/compositor/compositor.c b/compositor/compositor.c
index 23a496f2..ad5b8a77 100644
--- a/compositor/compositor.c
+++ b/compositor/compositor.c
@@ -1435,8 +1435,8 @@ int main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 	}
 
-	socket_name_size = 1 + asprintf(&socket_name, "%c%s", '\0',
-					option_socket_name);
+	socket_name_size =
+		asprintf(&socket_name, "%c%s", '\0', option_socket_name) + 1;
 
 	if (wl_display_add_socket(display, socket_name, socket_name_size)) {
 		fprintf(stderr, "failed to add socket: %m\n");