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Date:      Sun, 30 Aug 1998 11:04:53 -0400 (EDT)
From:      Robert Watson <robert@cyrus.watson.org>
To:        Alex Belits <abelits@phobos.illtel.denver.co.us>
Cc:        Craig Anderson <chanders@timing.com>, freebsd-hackers@FreeBSD.ORG, brhall@timing.com
Subject:   Re: Help with passing fd on FreeBSD
Message-ID:  <Pine.BSF.3.96.980830104935.4972B-100000@fledge.watson.org>
In-Reply-To: <Pine.LNX.4.02A.9808292150540.19313-100000@phobos.illtel.denver.co.us>

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I have a set of patches that try to clean up the fd-passing behavior in
3.0-CURRENT.  I originally wrote them to allow the passing of kernel
authorization tokens (http://www.watson.org/fbsd-hardening/tokens/).
These patches allow lkm's to hook the externalize, internalize, and gc
functions.

However, in the process of writing this, I have fixed at least a few
potential problems.  A few were just coding issues (like some underlying
assumptions about the size of mbufs and so on).  I have not fixed the bug
described in the BSD4.4 book (sorry, don't have it with me so don't have a
page number) w.r.t. garbage collecting fd's in listening sockets.

Passing tokens seems to work quite well for me.  Is the mbuf problem you
reported fixable by adding a sleep waiting for an mbuf?

On Sat, 29 Aug 1998, Alex Belits wrote:

> On Fri, 28 Aug 1998, Craig Anderson wrote:
> 
> > Can someone give me pointers on passing open file descriptors on FreeBSD?
> > This is covered in W. Richard Stevens Advanced programming book, but
> 
> See R. Stevens "TCP/IP Illustrated", volume 3, chapter 18.3
> or R. Stevens "Unix Network Programming", second edition (1997), volume 1,
> chapter 14.7.
> 
>   Previous books describe 4.3BSD and SVR4 fd passing that is more than
> slightly different.
> 
> > the structs in FreeBSD are slightly different, and I've never done this.
> 
> In FreeBSD CMSG_DATA(cm) macro is the equivalent to cm->cmsg_data that is
> commented out in include files in 4.4BSD-derived, but exists in
> other compatible systems.
> 
> Beware of the known bug in FreeBSD kernel (PR kern/4345).
> 
> --
> Alex
> 
> 
> 
> To Unsubscribe: send mail to majordomo@FreeBSD.org
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> 


  Robert N Watson 

Carnegie Mellon University            http://www.cmu.edu/
TIS Labs at Network Associates, Inc.  http://www.tis.com/
SafePort Network Services             http://www.safeport.com/
robert@fledge.watson.org              http://www.watson.org/~robert/



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