Server badges in Core

Norman Feske norman.feske at ...1...
Mon May 17 14:56:42 CEST 2010

Hi Steffen,

Steffen Liebergeld wrote:
> Although I hate answering myself, I find find the answer and I am
> sharing it with you.
> It turns out, that the badge that was submitted was invalid. I was able
> to circumvent this by adapting the Ipc_client::_call Method to set the
> badge to _dst.local_name(). This works for my scenario.

I don't know, what value you are using as 'local_name' (is this a unique
object ID as used for most of the supported kernels?). Great that you
found a solution for your current problem.

The way the 'Ipc_istream::badge' is handled depends very much on the
underlying kernel. So its hard to give a general answer to your
question. Generally speaking, the badge is used at the receiver side to
identify the addressed server object. On kernels w/o capability support,
each server object has a unique ID, known by both client and server.
When invoking the server object, the client supplies the unique object
ID as plain-data IPC payload. The server, in turn, uses the received ID
as badge, which, in turn, is used to look up the local 'Server_object'.
This is the scheme as you probably just noticed. On kernels with
capability support, the badge could be implemented differently. For
example, if the kernel's receive operation returns the invoked
capability selector at the server side, this capability selector could
be used as badge.


More information about the users mailing list