[PATCH wayland] client: Don't cancel a roundtrip when any event is received

[Kristian Høgsberg]

On Mon, Nov 26, 2012 at 11:25:53PM +0100, Jonas Ådahl wrote:
> Since wl_display_dispatch() returns the number of processed events or -1
> on error, only cancel the roundtrip if an -1 is returned.
> 
> This also fixes a potential memory corruption bug happening when
> wl_display_roundtrip() does an early return and the callback later
> writes to the then out of scope stack allocated `done' parameter.
> 
> Introduced by 33b7637b4500a682018b503837b8aca9afae36f2.

Ah, very nasty.  Thanks for figuring this out.

Kristian

> Signed-off-by: Jonas Ådahl <jadahl at gmail.com>
> ---
>  src/wayland-client.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/src/wayland-client.c b/src/wayland-client.c
> index 5fecc01..5ba2c45 100644
> --- a/src/wayland-client.c
> +++ b/src/wayland-client.c
> @@ -649,9 +649,12 @@ wl_display_roundtrip(struct wl_display *display)
>  	done = 0;
>  	callback = wl_display_sync(display);
>  	wl_callback_add_listener(callback, &sync_listener, &done);
> -	while (!done && !ret)
> +	while (!done && ret >= 0)
>  		ret = wl_display_dispatch(display);
>  
> +	if (ret == -1 && !done)
> +		wl_callback_destroy(callback);
> +
>  	return ret;
>  }
>  
> -- 
> 1.7.10.4
> 
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