Date: Fri, 21 Feb 2003 19:10:56 +0530 (IST)
From: Prasad <prasad_s@students.iiit.net>
To: lkml <linux-kernel@vger.kernel.org>
Subject: Syscalls on behalf of another process (was Syscalls in kernel space)
Message-ID: <Pine.LNX.4.44.0302211909140.1417-100000@students.iiit.net>
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(Resending the previous mail)

I am sorry for not being clear the previous time... but i think its time
to tell you where i needed it.  I, as a graduating project am working on a
distributed computing system, a part of which is "transparent process
migration in non-distributed environments".  In my system i would like to
ship the syscalls back to the original node(where the process originated).
so for that i have a kernel thread that takes the requests and is supposed
to execute the syscalls on behalf of the process (I have the idle task
structure existing on the originating node even after the process is
migrated to the other node).  And the question is how do i do that.  The
idea I had was to execute the functions behind the syscalls directly, but
again, these functions use a lot of 'current'.  Could you help me out of
this situation!
	An alternative was that if get_current was called I would check if
the 'current' points to my kernel thread and if i have a remote syscall
pending, then i would return a pointer to the particular process's
task_struct.  This I think is a work-around that should work.  Please do
comment on this too.

Prasad.

On Thu, 20 Feb 2003, Andrea Arcangeli wrote:
> > 
> > He is talking about directly calling the function behind the syscall,
> > not actually executing a syscall itself.
> 
> this is not what I understood from your previous discussion also given
> you suggest not to do that when he can call sys_read/sys_write instead
> because they're just exported etc.. I just wanted to add a better
> "never".
> 
> > syscalls should be made from userspace, not the kernel.
> 
> This is what I tried to say.
> 
> Andrea
> 

-- 
Failure is not an option


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