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To: Bill Paul <wpaul@skynet.ctr.columbia.edu>
cc: current@freebsd.org
Subject: Re: Plan for integrating Secure RPC -- comments wanted 
In-reply-to: Your message of "Tue, 17 Dec 1996 00:38:30 EST."
             <199612170538.AAA01464@skynet.ctr.columbia.edu> 
Date: Tue, 17 Dec 1996 08:30:05 +0100
Message-ID: <14804.850807805@critter.tfs.com>
From: Poul-Henning Kamp <phk@critter.tfs.com>
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In message <199612170538.AAA01464@skynet.ctr.columbia.edu>, Bill Paul writes:
>	int optlen;
>	int optval;
>	int sock;
>	int rval;
>
>	optlen = sizeof(optval);
>	rval = getsockopt(sock, SOL_SOCKET, SO_PEERUID, NULL, &optlen);
>				/*			^^^^		*/
>				/*	deliberate bug: should be &optval */
>
>According to the man page, getsockopt() should return EFAULT if optval
>or optlen aren't within the process's address space. Well, NULL is not
>within the process's address space, so I should get an error here, but
>I don't. If I do something equally silly like use -1 instead of NULL,
>then I get an EFAULT as expected. With NULL, the getsockopt() call doesn't
>do anything, but it returns an rval of 0 and doesn't set errno.
>
>Looking at the getsockopt() code, it seems like it short-circuits the
>uap->val (i.e. optval) == NULL case on purpose and doesn't return an
>error.
>
>Am I nuts, or is this a bug?

I belive the point is to return the length, so you can malloc sufficient
storage and call again.

--
Poul-Henning Kamp           | phk@FreeBSD.ORG       FreeBSD Core-team.
http://www.freebsd.org/~phk | phk@login.dknet.dk    Private mailbox.
whois: [PHK]                | phk@tfs.com           TRW Financial Systems, Inc.
Power and ignorance is a disgusting cocktail.