File Write Permission Rules

[Dave Decot]

> In article <630 at jonlab.UUCP> jon at jonlab.UUCP (Jon H. LaBadie) writes:
> <This is a future direction of UNIX question.
> <
> <I stumbled upon a system with /tmp directory permissions as follows:
> <
> <	drwsrwxrwx ......
> <
> <Note the "s". 
> <[...] namely a meaning for the set user id bit on directories.
> <The meaning?  Anyone could create files in the directory,
> <but only the owner of the directory, OR the owner of the individual
> <files could remove them.
> <So, the questions:
> <	1. Anyone know of the future fate of this useful tweak?
> 
> At a presentation to the Orange County Unix Users Group last month the
> AT&T speaker mentioned that Release 4 will support use of the suid bit
> on directories.  He didn't elaberate on its use, but I'll bet this is it.
> 
> Larry Dighera

SVID '89 says that the sticky bit is used for this purpose, not the setuid
bit.  It also says that this affects who can rename files in the directory
in the same way.  It does not mention any meaning for the setuid bit on
directories.

Dave