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Re: emulating no-senders notifications in L4?
From: |
Debian UserAd Buijsen |
Subject: |
Re: emulating no-senders notifications in L4? |
Date: |
Fri, 21 Dec 2001 15:09:54 +0100 (CET) |
>>
>> I think here the answer has to be no. BTW, one interesting question for L4
>> is: How do you prevent that a task sends its own, faked messages to the
>> server, circumventing the port right server. In other words, how do you
>> enforce the port server. This might involve some more RPCs the server has
>> to do with the port server.
>>
The next version of L4 will probably support IPC redirection, using an
in-kernel table of
sources and destinations. A 'privileged' task in user space will set this
table, thus controlling
whether entity A can send (directly) to entity B or not; in the latter case the
IPC will typically be
redirected to another entity. A 'one-shot' flag in the redirection table would
make it easy to
emulate send-once rights. The privileged task mentioned above could hand out
the port rights
and should do enough bookkeeping to clear up after tasks that have terminated
graciously or
violently.
In case you are wondering why I used the term 'entity' in stead of threads:
reading of the L4 list
at Karlsruhe suggests that the semantics of tasks and threads will change as
well. I really don't
think we can do anything fundamental about L4-hurd until the specs of L4V4 are
available.
Ad Buijsen
- Re: emulating no-senders notifications in L4?, Niels Möller, 2001/12/19
- Re: emulating no-senders notifications in L4?, Marcus Brinkmann, 2001/12/19
- Re: emulating no-senders notifications in L4?, Yoshinori K. Okuji, 2001/12/20
- Re: emulating no-senders notifications in L4?, Niels Möller, 2001/12/20
- Re: emulating no-senders notifications in L4?, Jean Wolter, 2001/12/20
- Re: emulating no-senders notifications in L4?, Niels Möller, 2001/12/20
- Re: emulating no-senders notifications in L4?, Marcus Brinkmann, 2001/12/20
- Re: emulating no-senders notifications in L4?, Jean Wolter, 2001/12/20
- Re: emulating no-senders notifications in L4?, Niels Möller, 2001/12/20
- Re: emulating no-senders notifications in L4?, Marcus Brinkmann, 2001/12/20
- Re: emulating no-senders notifications in L4?, Roland McGrath, 2001/12/20
- Re: emulating no-senders notifications in L4?, Thomas Bushnell, BSG, 2001/12/20