What you see is the userid under which the process is running
(presumably from "ps -ef" output). I'm not sure whether the
term "owner" is correctly conveying the UNIX concept, even
though the term "owner" might be widely used.

A process can change the userid while it is running, and this is
especially true for processes that are started as root or have
the "s-bit" set. oninit processes are of the latter kind, and they
do change userid during their life time.

Also, there's the UNIX concept of "real userid" and "effective
userid" which might also contribute to the perception that a
process might have 2 "owners". And that's where (for me at
least) the term "owner" looses its meaning ...

Anyway, for oninit processes it is quite normal that in a "ps -ef"
listing you see some running with userid "root" and other
(probably most of them) running with userid "informix".
There is nothing to worry about this. It should also not
disturb the OS-people ...

Regards,
Martin
--
Martin Fuerderer
IBM Informix Development Munich, Germany
Information Management

owner-informix-list@iiug.org wrote on 09.02.2005 10:40:47:

> Hi all,
>
> Again another question from my end regarding the oninit process. We
> have around 20 - 40 processes in the Linux Environment, where some of
> them have root as owner and rest as informix,
>
> Is it possible that one process can have more than one owners?
> If yes, please provide us with relavent information, so that I can
> check with the Operating system people.
>
> Awaiting for your information.
>
> Thanks and regards,
> --
> Arvind Patkar
> sending to informix-list

sending to informix-list

Martin Fuerderer wrote:
>Arvind Patkar asked:
>>Again another question from my end regarding the oninit process. We
>>have around 20 - 40 processes in the Linux Environment, where some of
>>them have root as owner and rest as informix,
>>
>>Is it possible that one process can have more than one owners?
>>If yes, please provide us with relavent information, so that I can
>>check with the Operating system people.
>
> What you see is the userid under which the process is running
> (presumably from "ps -ef" output). I'm not sure whether the
> term "owner" is correctly conveying the UNIX concept, even
> though the term "owner" might be widely used.
>
> A process can change the userid while it is running, and this is
> especially true for processes that are started as root or have
> the "s-bit" set. oninit processes are of the latter kind, and they
> do change userid during their life time.
>
> Also, there's the UNIX concept of "real userid" and "effective
> userid" which might also contribute to the perception that a
> process might have 2 "owners". And that's where (for me at
> least) the term "owner" looses its meaning ...
>
> Anyway, for oninit processes it is quite normal that in a "ps -ef"
> listing you see some running with userid "root" and other
> (probably most of them) running with userid "informix".
> There is nothing to worry about this. It should also not
> disturb the OS-people ...

What Martin says is pretty much accurate. The 'owner' reported by
commands such as 'ps' is based on the EUID (effective UID - I'm 95%
confident of this); similarly, the group is based on the EGID
(effective GID).

When IDS (oninit) is started by user informix, the CPU VPs run with
EUID informix, but the other VPs run with EUID root. Now, the
original question was asking whether a single process can have more
than one owner. With the caveats Martin outlined (he omitted the SUID
or saved UID, probably just for simplicity), the answer is "No".

However, it is perfectly feasible for the processes run by a single
instance of IDS to have different owners - because they are a number
of different but cooperating processes, initiated by a setuid-root
program. The SUID (setuid this time - yes, careless use of initial
letters, but predates my email) bit on oninit means the initial oninit
process has an EUID of root, and when the EUID of a process is root,
it can do anything.

--
Jonathan Leffler #include <disclaimer.h>
Email: jleffler@earthlink.net, jleffler@us.ibm.com
Guardian of DBD::Informix v2003.04 -- http://dbi.perl.org/