Subject: Re: Addition to force open to open only regular files
To: None <greywolf@starwolf.com>
From: Warner Losh <imp@village.org>
List: tech-kern
Date: 11/29/2000 00:04:47
In message <Pine.NEB.4.21.0011281542170.13212-100000@gandalf.starwolf.com> Greywolf writes:
: On Tue, 28 Nov 2000, Warner Losh wrote:
: 
: # : Okay, is there a reason that getfh() shouldn't be mortal-enabled? It
: # : already does path checking for accessibility; and since a stat() on a
: # : non-readable file is ok, fhstat shouldn't be a problem, either.
: # 
: # stat on a non-readable file is a problem as it currently isn't
: # allowed.
: 
: stat is most certainly allowed on a non-readable file!  How else would
: ls(1) work?  :-)

My mistake.  I should have said that stat for non-readable files is
disallowed when components in the path are unreadable.  My mistake for
being imprecice.

: Damn.  There's GOT to be a way to avoid the race condition; getfh() looked
: so ideal.

The race saved by getfh() I think causes kernel resources to be
consumed.  The getfh call locks the leaf and leaving it locked on
return to userland seems to be dangerous to me.

Warner