Date: Mon, 12 Feb 2007 15:09:09 +0300 From: Yar Tikhiy <yar@comp.chem.msu.su> To: Brooks Davis <brooks@FreeBSD.org> Cc: cvs-src@FreeBSD.org, Ceri Davies <ceri@submonkey.net>, cvs-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: cvs commit: src/etc/rc.d hostname Message-ID: <20070212120908.GN13808@comp.chem.msu.su> In-Reply-To: <20070212034438.GA42410@lor.one-eyed-alien.net> References: <200702101313.l1ADDX8m056868@repoman.freebsd.org> <20070210205228.GE9455@submonkey.net> <20070211085317.GF13808@comp.chem.msu.su> <20070212034438.GA42410@lor.one-eyed-alien.net>
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On Sun, Feb 11, 2007 at 09:44:38PM -0600, Brooks Davis wrote:
> On Sun, Feb 11, 2007 at 11:53:17AM +0300, Yar Tikhiy wrote:
> > On Sat, Feb 10, 2007 at 08:52:28PM +0000, Ceri Davies wrote:
> > > On Sat, Feb 10, 2007 at 01:13:33PM +0000, Yar Tikhiy wrote:
> > > > yar 2007-02-10 13:13:33 UTC
> > > >
> > > > FreeBSD src repository
> > > >
> > > > Modified files:
> > > > etc/rc.d hostname
> > > > Log:
> > > > Handle the case when the admin forgot to set $hostname,
> > > > which can happen in new installations: advise to set the
> > > > variable and refer to rc.conf(5).
> > >
> > > Isn't it possible for the hostname to come via DHCP? How does this
> > > behave in that case (or rather, I can see how it behaves; is that the
> > > right thing)?
> >
> > I've never played with setting the hostname via DHCP. In my change,
> > I just tried not to break the existing code related to DHCP. Perhaps
> > someone using DHCP to get the hostname could shed light on the topic.
>
> This appears mostly harmless for systems that get their hostname via
> DHCP. They will get a warning, but it will otherwise work.
Now I see. The code getting $hostname via kenv from dhcp.host-name
is for the case when the host was booted via PXE. OTOH, a usual
DHCP client will run dhclient when it comes to setting up network
interfaces, i.e., after /etc/rc.d/hostname. Perhaps we need
a way to indicate that the hostname will be assigned automatically
and the nagging message shouldn't be emitted. E.g., in rc.conf:
hostname="DHCP"
I have no idea how many Unix hosts allow their hostname to be set
via DHCP. I prefer to think that a Unix host is like a good ship:
it never changes its name while furrowing the network seas. A DHCP
assigned hostname better fits crippled hosts such as diskless
stations etc.
> -- Brooks
>
> > > > | @@ -58,7 +58,16 @@ hostname_start()
> > > > | fi
> > > > | fi
> > > > |
> > > > | - /bin/hostname ${hostname}
> > > > | + # Have we got a hostname yet?
> > > > | + #
> > > > | + if [ -z "${hostname}" ]; then
> > > > | + warn "\$hostname is not set -- see ${rcvar_manpage}."
> > > > | + return
> > > > | + fi
> > > > | +
> > > > | + # All right, it is safe to invoke hostname(1) now.
> > > > | + #
> > > > | + /bin/hostname "${hostname}"
> > > > | echo "Setting hostname: `hostname`."
> > >
> > > Are the backticks necessary here? Why don't we use ${hostname}?
> >
> > Thus we determine what name has actually been set. Our doing so
> > reeks of paranoia, of course. :-) Perhaps a better ordering would
> > be:
> >
> > echo "Setting hostname: ${hostname}."
> > /bin/hostname "${hostname}"
> >
> > So possible error messages will follow the introductory statement,
> > which makes more sense. Any objecttions?
> >
> > --
> > Yar
> >
--
Yar
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