Re: Problem with setting up namespaces

Hi Johannes,

I extended Björns example, see attachment. Now a trusted app creates the
IPC gate, which can be used for client-server communication. 

To try the example you have to use the attached patch. 

Best regards,
Tobias


On Thu, 2013-07-18 at 21:00 +0200, Johannes Schlatow wrote:
> Thanks Björn.
> 
> The problem I have is not lua specific though. I was not only trying to
> pass the client capability via namespaces (which works perfectly as you
> just demonstrated) but also to register the server capability of an
> ipc_gate to the server's namespace.
> 
> Basically, I don't want the server to create the ipc_gate by itself.
> Instead I have another (trusted) application that has access to both
> namespaces (i.e. the one of the server and the one of the client). This
> application creates the ipc_gate and registers its capability with
> appropriate rights to the corresponding namespaces.
> 
> The lua config I sent initially was just my approach to reproduce this
> problem without posting too much of my code and to minimize the PEBKAC
> factor ;)
> 
> Johannes
> 
> On Thu, 18 Jul 2013 18:53:37 +0200
> Björn Döbel <[email protected]> wrote:
> 
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > Hi Johannes,
> > 
> > >> Well, I want to provide capabilities for an application by
> > >> putting them into a local namespace. Since our system changes
> > >> dynamically I want to add capabilities at runtime by registering
> > >> them to the corresponding namespace.
> > 
> > please find attached the clntsrv example adapted to use namespaces.
> > The general approach is:
> > 
> > 1) In the Lua config create an empty namespace and make it accessible
> >    to your application(s). Note that the example also uses different
> >    access rights for client and server.
> > 
> > 2) On the server side I use the object registry's register_object()
> >    function, which internally creates an IPC gate and binds the
> > calling thread to it. Then I use the namespace's register_object()
> > call to make the new channel externally visible.
> > 
> > 3) In the client I query for the object name. This call blocks until
> >    the server has registered the new channel.
> > 
> > Apart from these steps, client and server implementation are identical
> > to the original example.
> > 
> > Regarding your approach of putting a channel into the namespace within
> > the Lua config file: This does not work for me. We are still trying to
> > figure out, why. It's probably indeed be related to the downgrading as
> > suggested by Christian.
> > 
> > Bjoern
> > -----BEGIN PGP SIGNATURE-----
> > Version: GnuPG v1.4.12 (GNU/Linux)
> > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
> > 
> > iEYEARECAAYFAlHoHZAACgkQP5ijxgQLUNlt0wCfX3qShBjEXdXvaXGmVtbk5IgG
> > Ys8An2vS/Uqj5qrFyKVxFAvGBB0BgtE0
> > =0Qez
> > -----END PGP SIGNATURE-----
> 
> 
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Index: pkg/l4re/util/libs/name_space_svr.cc
===================================================================
--- pkg/l4re/util/libs/name_space_svr.cc (revision 42493)
+++ pkg/l4re/util/libs/name_space_svr.cc (working copy)
@@ -164,7 +164,7 @@
       if (n->obj()->is_rw())     flags |= L4_FPAGE_RX;
       if (n->obj()->is_strong()) flags |= L4_FPAGE_RW;
 
-      ios << L4::Ipc::Snd_fpage(n->obj()->cap().fpage(flags));
+      ios << L4::Ipc::Snd_fpage(n->obj()->cap(), flags );
       _dbg.printf(" result = %lx flgs=%x strg=%d\n",
                   result, flags, (int)n->obj()->is_strong());
       return result;
Index: include/impl/namespace_impl.h
===================================================================
--- pkg/l4re/include/impl/namespace_impl.h       (revision 42493)
+++ pkg/l4re/include/impl/namespace_impl.h       (working copy)
@@ -128,7 +128,7 @@
   io << L4::Opcode(L4Re::Namespace_::Register)
      << flags << L4::Ipc::Buf_cp_out<char const>(name, strlen(name));
   if (o.is_valid())
-    io << L4::Ipc::Snd_fpage(o.fpage(L4_FPAGE_RWX & flags));
+    io << L4::Ipc::Snd_fpage(o, L4_FPAGE_RWX & flags) ;
   l4_msgtag_t res = io.call(cap(), L4Re::Protocol::Namespace);
   return l4_error(res);
 }