Re: multiple capabilities in a single RPC

[Neal H. Walfield]

Marcus,

At Wed, 19 Jan 2005 21:09:14 +0100,
Marcus Brinkmann wrote:
> 
> At Wed, 19 Jan 2005 18:38:30 +0000,
> Neal H. Walfield wrote:
> > We need to move the declaration of struct _hurd_cap_list_item from
> > cap-server-internal.h to cap-server.h.  The whole point of the use
> > context is to create the list items on the stack and not allocate them
> > internally.
> 
> Ok.  I don't know how we will ever maintain ABI compatibility with
> this mess.

This is a good point.  It is worth pointing out that we don't actually
need to expose any of the members of a cap use context to users: it is
just a way to save information for the eventual ctx_end_cap_use call.
The problem that we solve by exposing the structure is that since
libhurd-cap-server doesn't know how to best allocate memory, the
caller has to do it and for this, it needs the size of the ctx
structure.  We can also expose this information using a function.
The caller would than have something along the lines of:

  struct hurd_cap_ctx_cap_use *cap_ctx = alloca (hurd_cap_ctx_size ());

What do you think?

Thanks,
Neal