Subject: Re: Addition to force open to open only regular files
To: Warner Losh <>
From: Thor Lancelot Simon <>
List: tech-kern
Date: 11/28/2000 18:20:15
On Tue, Nov 28, 2000 at 04:06:27PM -0700, Warner Losh wrote:
> The talk on the FreeBSD side of the world is that these calls should
> quietly die a quick and sudden death.  They are fore the nfs server
> only and there are practicle problems with their use.  The problems
> aren't easily solved.  I'm not sure of all the details, but I thought
> I'd let the NetBSD community know what some in the FreeBSD community
> are thinknig.

Are we talking about the same "these calls"?  I don't know of any "nfs
server" that uses fhopen() and I know of no practical problems with its
use.  fhopen() is essentially a hack to allow user processes to bypass the
namei cache, and it's a huge win for some applications (think of something
that manages many, many individual files, accessed in patterns that seem
random to the namei cache; say, an old-style Usenet news server; with
open-by-filehandle, it can implement its _own_ namei cache and not thrash
the system one).

If you're talking about linux' setfsuid(), then yes, it's a nasty hack to
support their nfs server and should die.  In particular, it's not really
even possible to emulate it safely because it's defined to return 0 even
if it fails, so you can leave the emulated process thinking it dropped
root privs when actually it didn't.  Nice, huh?

So, what exactly is your notion of "these calls"?

Thor Lancelot Simon	                            
	the effort to perceive simply the cruel radiance of what is