Re: Removing /etc/nologin on shutdown

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Sun, 23 May 2010 09:30:13 -0400
    From:        "Ian D. Leroux" <idleroux%fastmail.fm@localhost>
    Message-ID:  
<1274621413.29560.1376468763%webmail.messagingengine.com@localhost>

  | - If so, is it /sbin/shutdown's job to remove it, or something in the
  |   /etc/rc.d scripts?  Where should I look to find out why this isn't
  |   happening as it should?

It doesn't if you run it with -r or -h (or -p which implies -h) - though
it probably should.

If shutdown ever calls its internal finish() function (and -k wasn't used)
it does unlink /etc/nologin

But that never happens when it runs with -h or -r - instead shutdown
exec's reboot or halt.   Those programs know nothing of /etc/nologin,
and so cannot remove it.

Most likely, shutdown should be removing /etc/nologin immediately before it
exec's reboot (or halt) - that would leave a race condition (it would be
possible for someone to log in in the very small gap between the unlink and
when reboot (or halt) actually does its thing, but I doubt that's going to
bother anyone very much.

What should happen if the exec fails I will leave for someone else to
ponder!

kre