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Date:      Sun, 27 Feb 2000 12:51:40 +0800
From:      Peter Wemm <peter@netplex.com.au>
To:        "Jordan K. Hubbard" <jkh@zippy.cdrom.com>
Cc:        Alfred Perlstein <bright@wintelcom.net>, Robert Watson <robert+freebsd@cyrus.watson.org>, "Jordan K. Hubbard" <jkh@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject:   Re: cvs commit: src/sys/kern init_main.c 
Message-ID:  <20000227045140.E6C3F1CDE@overcee.netplex.com.au>
In-Reply-To: Message from "Jordan K. Hubbard" <jkh@zippy.cdrom.com>  of "Fri, 25 Feb 2000 12:05:49 PST." <96345.951509149@zippy.cdrom.com> 

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"Jordan K. Hubbard" wrote:
> > It's be nice if it was possible, the last time I looked at any Linux
> 
> Guys, you're clearly just not hearing me.  The issue here isn't
> whether or not the information would be useful, it's how to get it
> when you've booted off a FreeBSD installation boot floppy.
> /var/run/dmesg.boot is created by the clean_var() function in /etc/rc,
> something which only runs when the system is actually booted.  I also
> don't have dmesg available on the boot floppy and even if I did, I
> suspect it would have a rather annoying time attempting to do a
> kvm_open() on a gzipped kernel image.

Just as a datapoint, all that is required is /dev/[k]mem - the kernel isn't
required anymore.  kvm_open() etc use kldsym() if running on a live kernel
and do not nlist() the boot kernel anymore.  It should be safe to use
dmesg(8) in a pipe on the boot floppy.  This works even if the kernel is
stripped (as it is on MFSROOT), as long as dmesg() isn't trying to get to
static symbols.

root@overcee[12:46pm]~-675# chflags noschg /kernel
root@overcee[12:46pm]~-676# mv /kernel /kernel.no
root@overcee[12:46pm]~-677# dmesg | head
Copyright (c) 1992-2000 The FreeBSD Project.
Copyright (c) 1982, 1986, 1989, 1991, 1993
        The Regents of the University of California. All rights reserved.
FreeBSD 4.0-CURRENT #406: Thu Feb 24 13:38:09 WST 2000
    peter@overcee.netplex.com.au:/home/src/sys/compile/OVERCEE
...

Cheers,
-Peter



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