freebsd-dev/etc/rc.d/hostid
Doug Barton 2822c33f8c This change does the following for the scripts that run up through
FILESYSTEMS (the default early_late_divider):
1. Move sysctl to run first
2. Move as many BEFOREs to REQUIREs as possible.
3. Minor effect, move hostid_save from right before mdconfig to right
   after.

A lot of the early scripts make use of sysctl one way or another so
running this first makes a lot of sense given that system-critical
values are often placed in sysctl.conf.

My original purpose for working on this was that while doing some
debugging on other stuff I noticed that the order of execution was
different in the first pass through the early scripts and the second.
In practice that doesn't matter because the scripts are not executed the
second time. However this _can_ result in problems if the difference in
the rcorder moves a script from the late section to the early section in
the second pass (which would mean the script would not get executed).
So, I wanted to make the order of execution of the scripts in the early
section more deterministic.

In the course of debugging the ordering problems I noticed that moving
the BEFOREs to REQUIREs prevented the changes in order from the first
pass to the second pass without having to make any substantial changes.
(Of course it's no secret that I think BEFORE should be avoided as much
as possible, but this is a good example of why.)

Reviewed by:	silence on freebsd-rc@
MFC after:	8.1-RELEASE
2010-05-19 19:03:19 +00:00

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#!/bin/sh
#
# Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
# PROVIDE: hostid
# REQUIRE: sysctl
# KEYWORD: nojail
. /etc/rc.subr
name="hostid"
start_cmd="hostid_start"
stop_cmd=":"
reset_cmd="hostid_reset"
extra_commands="reset"
rcvar="hostid_enable"
hostid_set()
{
uuid=$1
# Generate hostid based on hostuuid - take first four bytes from md5(uuid).
id=`echo -n $uuid | /sbin/md5`
id="0x${id%????????????????????????}"
# Set both kern.hostuuid and kern.hostid.
#
check_startmsgs && echo "Setting hostuuid: ${uuid}."
${SYSCTL_W} kern.hostuuid="${uuid}" >/dev/null
check_startmsgs && echo "Setting hostid: ${id}."
${SYSCTL_W} kern.hostid=${id} >/dev/null
}
hostid_hardware()
{
uuid=`kenv -q smbios.system.uuid`
x="[0-9a-f]"
y=$x$x$x$x
case "${uuid}" in
$y$y-$y-$y-$y-$y$y$y)
echo "${uuid}"
;;
esac
}
hostid_generate()
{
# First look for UUID in hardware.
uuid=`hostid_hardware`
if [ -z ${uuid} ]; then
# If not found, fall back to software-generated UUID.
uuid=`uuidgen`
fi
hostid_set $uuid
}
hostid_reset()
{
hostid_generate
# Store newly generated UUID in ${hostid_file}.
echo $uuid > ${hostid_file}
if [ $? -ne 0 ]; then
warn "could not store hostuuid in ${hostid_file}."
fi
}
hostid_start()
{
# If ${hostid_file} already exists, we take UUID from there.
if [ -r ${hostid_file} ]; then
hostid_set `cat ${hostid_file}`
else
# No hostid file, generate UUID.
hostid_generate
fi
}
load_rc_config $name
run_rc_command "$1"