moving file descriptor passing into a header

[Colin Walters]

On Tue, Apr 13, 2010 at 7:12 PM, Lennart Poettering <mzqohf at 0pointer.de> wrote:
>
> And then, this breaks in *any* case when fds are involved. Regardless if
> you demarshal/marshal to/from fds or fd indexes. Because after all the
> marshalled blob is exactly the same. The distinction is purely in the
> API for it.

True, as things are currently, dbus_message_marshal would copy the
header field.  However, if someone did "content marshalling" as Thiago
posted, they would no longer be copying the fds, which I would pretty
strongly is almost always what's desired for that case.

For example something like:
http://alban.apinc.org/blog/2010/04/01/d-bus-debugging-how-to-use-d-feet-on-n900/
Definitely does not want to try to copy file descriptors, because it's
clearly going to fail over TCP =)

We may want to add an explicit dbus_message_clone or something which
just copies content, interface, and path.  But not serial, destination
or any of the other headers (i.e. definitely not file descriptors).