Hi Andrew,

On 04/11/2016 08:56 PM, Andrew Zaborowski wrote:
> Keep sending the message header+padding as a separate
> KDBUS_ITEM_PAYLOAD_OFF buffer like in DBus-1, the systemd busctl utility
> also seems to do that.  But fix what we send after the header.
> ---
>   ell/dbus-kernel.c  | 17 +++++++++--------
>   ell/dbus-message.c | 19 +++++++++++++++++++
>   ell/dbus-private.h |  3 +++
>   3 files changed, 31 insertions(+), 8 deletions(-)
>
> diff --git a/ell/dbus-kernel.c b/ell/dbus-kernel.c
> index 7797153..da5920f 100644
> --- a/ell/dbus-kernel.c
> +++ b/ell/dbus-kernel.c
> @@ -427,14 +427,15 @@ int _dbus_kernel_send(int fd, size_t bloom_size, uint8_t bloom_n_hash,
>   	item->vec.size = header_size;
>   	item = KDBUS_ITEM_NEXT(item);
>
> -	body = _dbus_message_get_body(message, &body_size);
> -	if (body_size > 0) {
> -		item->size = KDBUS_ITEM_HEADER_SIZE + sizeof(struct kdbus_vec);
> -		item->type = KDBUS_ITEM_PAYLOAD_VEC;
> -		item->vec.address = (uintptr_t) body;
> -		item->vec.size = body_size;
> -		item = KDBUS_ITEM_NEXT(item);
> -	}
> +	_dbus_message_build_contents(message, NULL, &body_size);
> +	body = alloca(body_size);

This will fail badly somewhere around body_size >= 64k, depending on the 
platform.  Why can't we write the contents directly like we used to?

> +	_dbus_message_build_contents(message, body, NULL);
> +
> +	item->size = KDBUS_ITEM_HEADER_SIZE + sizeof(struct kdbus_vec);
> +	item->type = KDBUS_ITEM_PAYLOAD_VEC;
> +	item->vec.address = (uintptr_t) body;
> +	item->vec.size = body_size;
> +	item = KDBUS_ITEM_NEXT(item);
>
>   	kmsg->size = (void *)item - (void *)kmsg;
>

Regards,
-Denis