Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!uflorida!haven!uvaarpa!virginia!scl
From: scl@virginia.acc.virginia.edu (Steve Losen)
Newsgroups: comp.sys.att
Subject: Re: mvdir: where is it, how can I get it?
Message-ID: <1050@virginia.acc.virginia.edu>
Date: 13 Sep 88 16:55:57 GMT
References: <15911@shemp.CS.UCLA.EDU>
Reply-To: scl@virginia.acc.Virginia.EDU (Steve Losen)
Organization: University of Va., Charlottesville, VA
Lines: 36

In article <15911@shemp.CS.UCLA.EDU> cc1@CS.UCLA.EDU (Michael Gersten) writes:
>Now, its not the absolute end of the world. I can put in ~/bin the
>following little thing
>
>main(argc,argv) char **argv;
>{
>	link (argv[1], argv[2]);
>	unlink (argv[1]);
>}
>
>, add some checks, and make it 6777, owned by root, in a directory only
>I can use, but still, why?
>
>			Michael

Moving a directory around takes a little more effort than the folks at
AT&T were willing to put forth, I suppose.  Besides just moving the
the directory itself, you must fix its ".." entry.  Another problem is
that you must be root to link/unlink a directory and we all know what
gaping security problems setuid to root programs can cause.  You also
don't want to allow people to do things like

"mv . foo" or "mv .. foo" (or "mv x/. foo" for that matter)

or you'll lose . and .. entries.  Furthermore, you can't allow a
directory to be moved into its own subtree or you'll disconnect it
from the file system, i.e.,   mv x x/y

I have modified mv/cp/ln and /usr/lib/mv_dir to correctly move
directories.  (not just rename them)  If anyone with an AT&T sysV source
licence wants it, I'll be happy to give it to you.  I've also
implemented the Berkeley "-i" option that asks for confirmation before
clobbering an existing file.
-- 
Steve Losen     scl@virginia.edu
University of Virginia Academic Computing Center