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Is system the same as sys?

Linda Card
Frequent Advisor

Is system the same as sys?

On other UNIX systems, the sys group is a privileged group. On Tru64, is the group system the equivalent to the group sys?
4 REPLIES
Ivan Ferreira
Honored Contributor

Re: Is system the same as sys?

The system group could be equivalent to the sys group, because members of this group can run some commands that other cannot, for example, collect and su.
Por que hacerlo dificil si es posible hacerlo facil? - Why do it the hard way, when you can do it the easy way?
Linda Card
Frequent Advisor

Re: Is system the same as sys?

Ivan, thank you for your quick response.

I was hoping for a definitive answer on the responsibilities of the system group. U.S. government security is familiar with the UNIX group named "sys" but Tru64 does not have a "sys" group. I am looking for clarification that the Tru64 group named "system" (GID 0) is the same as other UNIX group named "sys".

Can you clarify/verify?

Linda
Mark Poeschl_2
Honored Contributor

Re: Is system the same as sys?

I'm betting there is no "official" documentation that GID 0 (no matter what alphabetic name it's given) must be used for the system privileged group. The Wikipedia article for "Group ID" indicates the opposite, but look at this quote taken directly from the IEEE UNIX Standards document:

"3.19 Appropriate Privileges
An implementation-defined means of associating privileges with a process with regard to the function calls, function call options, and the commands that need special privileges. There may be zero or more such means. These means (or lack thereof) are described in the conformance document."

One of these "means" could clearly be comparing a process' group identifier with some special value reserved for system use. The fact that the standard does not require any such "means" and that individual implementers must describe their chosen "means" (if any) in a conformance document tells me that group ID 0 has no truly official standing.


Ann Majeske
Honored Contributor

Re: Is system the same as sys?

What he said :)

Mark is right that the number (GID=0) is more important than the name (sys vs system). If the sys group on the other flavors of UNIX that the US Government types are familiar with is GID 0 the use and functionality of the system group on Tru64 should be pretty close to the sys group. But, also as Mark said, there's no official documentation that I know of that lists or restricts the responsibilities of group 0 regardless of it's name. Each flavor of UNIX is different, so even if you had two flavors that used the name "sys" I don't think there's any guarantee that the use of the group would be exactly the same between those flavors.

The two uses that I can think of off hand for the system group are:
1) It is the root user's primary group
2) It allows other users that are in the group to do some things that are normally not allowed, e.g. su to root and run collect as Ivan said.

Ann