Attach my own pid

[bernd@petrovitsch.priv.at (Bernd Petrovitsch)]

On Die, 2016-03-22 at 01:26 -0400, Valdis.Kletnieks at vt.edu wrote:
> On Mon, 21 Mar 2016 16:01:41 +0530, Nitin Varyani said:
> 
> > I am running a master user-level process at Computer 1 which sends a
> > process context like code, data, registers, PC, etc as well as *"pid"* to
> > slave processes running at other computers. The responsibility of the slave
> > process is to fork a new process on order of master process and attach *"pid"
> > *given by the master to the new process it has forked. Any system call on
> > slave nodes will have an initial check of " Whether the process belongs to
> > local node or to the master node?". That is, if kernel at Computer 2 pid of
> > the process is 1500
> 
> None of that requires actually controlling the PID of the child.

Well, I think that the OP wants to map the PIDs with a fixed offset per
host. So e.g. the local PID == 14 becomes 20014 on all other nodes.
At least for debugging it's easier than some random mappings;-)

As for top post: TTBOMK there is no SysCall for doing that.
* Perhaps one can achieve something similar with containers - one
  container per remote host or so (but I never used containers actively
  myself) or (ab)use KVM (does vServer still live?) for local
  "pseudo-VMs" (and use there the original PIDs - or so).
* The manual page of clone(2) doesn't reveal to me if it's possible to
  wish for a PID.
* You could clone (pun not intended;-) the fork() syscall and add an
  parameter - the PID - to it (and e.g. return -1 if it's already used).

BTW I don't know how the rest of the kernel reacts to such artifical
PIDs (but you will see;-) outside the "official range".

MfG,
	Bernd
-- 
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