Date: Tue, 08 Jun 1999 02:40:57 +0100 From: Brian Somers <brian@Awfulhak.org> To: "Eugene M. Kim" <gene@nttmcl.com> Cc: hackers@freebsd.org Subject: Re: Session leader releasing the ctty Message-ID: <199906080140.CAA14092@keep.lan.Awfulhak.org> In-Reply-To: Your message of "Mon, 07 Jun 1999 17:14:48 PDT." <Pine.BSF.4.10.9906071658080.93580-100000@firee.ia.cp>
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> Hello,
>
> I'm having a trouble programming a special login shell, and would like
> to hear any opinions on this.
>
> I want this shell (which automatically becomes a session leader) to
> release its ctty but remain unterminated (the ctty must be taken by its
> child). However, there seems to be no easy way to do this; termios(4)
> says one must call setsid() to release its ctty, but setsid(2) says the
> call will fail if the caller is already a session leader.
>
> Would there be any other way for a session leader to release its ctty
> without terminating itself? TIA.
You need to also drop your process id so that you're not the owner of
the process group that the terminal points at. Check bundle_setsid()
in src/usr.sbin/ppp/bundle.c. A second fork() is done here because
the parent may continue and doesn't want to figure out how to reap
the child - you probably don't need this if the original process is
going to go away soon anyway.
> Cheers,
> Eugene Kim
>
> PS. I'm now using a workaround that the shell will forward the SIGHUP
> that it received because it's a session leader, but this isn't a clean
> way. :-p
>
> --
> Eugene M. Kim NTT Multimedia Communications Laboratories
> Software Developer 250 Cambridge Avenue, Suite 205
> +1 650 833 3630 (Voice) Palo Alto, CA 94040, USA
> +1 650 833 3633 (Fax) mailto:gene@nttmcl.com
--
Brian <brian@Awfulhak.org> <brian@FreeBSD.org>
<http://www.Awfulhak.org>; <brian@OpenBSD.org>
Don't _EVER_ lose your sense of humour ! <brian@uk.FreeBSD.org>
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