Date: Tue, 25 Mar 1997 21:49:03 GMT From: Bob Bishop <rb@gid.co.uk> To: Bruce Evans <bde@zeta.org.au> Cc: freebsd-current@freebsd.org, joerg_wunsch@uriah.heep.sax.de, terry@lambert.org Subject: Re: 2.2R (src 2.2 211): <ctrl><alt><del> == dialing Message-ID: <l03020901af5df65f0f3b@[194.32.164.2]> In-Reply-To: <199703250234.NAA06930@godzilla.zeta.org.au>
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At 2:34 am -0000 25/3/97, Bruce Evans wrote:
>This has nothing to do with POSIX signals...
Oh, OK, I'll come out of my sulk now :-)
>...or process groups. It is much
>simpler. It is mostly documented in init(8):
>
>1. If someone hits Ctrl-Alt-Del, then a SIGINT is usually sent to init.
>2. Init shuts down and reboots when it receives a SIGINT.
>3. Init shuts things down by broadcasting signals of increasing severity
> { SIGHUP, SIGTERM, SIGKILL }.
>4. Some process like ppp do bad things when they receive a SIGHUP.
>
>This differs from when the system is shut down using reboot(8). reboot
>shuts things down by broadcasting signals of increasing severity
>{ SIGTERM, SIGKILL }. I don't know why init broadcasts SIGHUP...
That I can tell you: interactive shells don't respond to SIGTERM. OTOH,
init shouldn't send SIGHUP to daemons (ie sessions with no controlling tty)
because they mostly take HUP to mean "reread your config".
>...or why reboot doesn't just signal init.
Good question; as it stands, it appears that reboot will always SIGKILL
interactive shells (which ignore TERM); under unfavourable circumstances
this could eg leave modems in strange states.
--
Bob Bishop (0118) 977 4017 international code +44 118
rb@gid.co.uk fax (0118) 989 4254 between 0800 and 1800 UK
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