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To: Greg <gkurz@fr.ibm.com>
Cc: Linus Torvalds <torvalds@osdl.org>,
       Hubertus Franke <frankeh@watson.ibm.com>,
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       Cedric Le Goater <clg@fr.ibm.com>
Subject: Re: RFC [patch 13/34] PID Virtualization Define new task_pid api
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From: ebiederm@xmission.com (Eric W. Biederman)
Date: Thu, 02 Feb 2006 07:09:27 -0700
In-Reply-To: <43E20E31.2030601@fr.ibm.com> (gkurz@fr.ibm.com's message of
 "Thu, 02 Feb 2006 14:50:41 +0100")
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Greg <gkurz@fr.ibm.com> writes:

>> Well that assertion will fail.
>> At that point getppid() will return 0, and getpid() will return 1.
>> 
>> Processes getting confused is their own problem.
>> 
>
> This flavour of clone should be used with great care then since it breaks the
> usual unix process semantics. :)

Do you know of a flavor of clone (besides fork) that doesn't share that
property?

For the most part I am not breaking the usual process semantics I work
very hard to preserve it but simply which pids you see are different.
Which what would be expected.

>> Now there will be a pid that the parent sees that will not be 0.
>> And that is what the parent will see in the context of wait.
>> 
>> In my code I introduced a wid (wait id) for that purpose.
>> 
>
> Is it possible to see the code ?

git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-ns.git/

The tree is still at the proof of concept level but it does come fairly close
to what has been discussed.

Eric