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From: Julian Elischer <julian@ref.tfs.com>
Message-Id: <199509180806.BAA01219@ref.tfs.com>
Subject: Re: suspect code in 'unlink' syscall.
To: julian@ref.tfs.com (Julian Elischer)
Date: Mon, 18 Sep 1995 01:06:48 -0700 (PDT)
Cc: hackers@freebsd.org
In-Reply-To: <199509180750.AAA01170@ref.tfs.com> from "Julian Elischer" at Sep 18, 95 00:50:32 am
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> 
> looking at 'unlink (2)'
> I see,
>         if (vp->v_type != VDIR ||
>             (error = suser(p->p_ucred, &p->p_acflag)) == 0) {
>                 /*
>                  * The root of a mounted filesystem cannot be deleted.
>                  */
>                 if (vp->v_flag & VROOT)
>                         error = EBUSY;
>                 else
>                         (void) vnode_pager_uncache(vp);
>         }
> 
> I translate this as:
> "if it's not a DIR, or we are root",
> check if we are deleteing the 
> root of an FS,
> if not, flush cache......
> 
> now, if we were NOT root, and it IS a dir...... (normal...)
> 
> can we delete it?
The answer is 'NO' but I'm not sure I see why..

AH I just found it.. only root can unlink a dir, all others can
only do 'rmdir' calls.. ok, I admit it..  I need to go to sleep.

> I'm about to try this..
> if you don't hear from me, the building exploded...
It didn't
> 
> julian :)
> 
>