Re: mkdir() and group id

[Thomas Bushnell, BSG]

Oystein Viggen <oysteivi@tihlde.org> writes:

> The difference is that the SysV way won't work for more than one level
> of directories.  Once you start making dirs within dirs[1], your sgid is
> not inherited, and group ownership falls back to your default group,
> instead of what you want.

I was just told that the setgid bit does get inherited on the new
directories. 

> By the way, the scenario described by Thomas doesn't work for /tmp, as
> it gives users access to each others' temp files.  (Provided, that is,
> that you use group 0 as "wheel", as is currently the case with several
> Linux distributions.)

That's incorrect.  /tmp is owned by group zero, but none of the users
are in group zero, so their files don't inherit gid from the
directory.  (You only inherit gid if you are a member of the group.)