Date: Wed, 4 Aug 1999 12:59:44 -0400 (EDT) From: "Brian F. Feldman" <green@FreeBSD.org> To: Assar Westerlund <assar@sics.se> Cc: Mike Smith <mike@smith.net.au>, Matthew Dillon <dillon@apollo.backplane.com>, Ollivier Robert <roberto@keltia.freenix.fr>, hackers@FreeBSD.org Subject: Re: Jail syscalls Message-ID: <Pine.BSF.4.10.9908041251530.55682-100000@janus.syracuse.net> In-Reply-To: <5lr9ljssjj.fsf@assaris.sics.se>
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On 4 Aug 1999, Assar Westerlund wrote:
> "Brian F. Feldman" <green@FreeBSD.ORG> writes:
> > On Tue, 3 Aug 1999, Mike Smith wrote:
> > >
> > > Actually, with interfaces like this you should generally pass a pointer
> > > to the structure in userspace, and stick a version number constant in
> > > the beginning of the structure. The size is often not enough of a
> > > determining factor...
> >
> > Actually, the structure shouldn't change size because it should be
> > using a sockaddr.
>
> No, because sizeof(struct sockaddr) < sizeof(struct sockaddr_in6).
> This is kind of bad but that's the way it is. It would make sense to
> use a `struct sockaddr_storage' but I still think it's worthwhile and
> better to have a version number.
As I read it, sockaddr is a transparent type (overloaded, as it were).
So we would use something like:
struct jail {
...
struct sockaddr;
char [SOCK_MAXADDRLEN - sizeof(struct sockaddr)];
char [sizeof(int) - SOCK_MAXADDRLEN % sizeof(int)];/* padding */
...
}
>
> /assar
>
>
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