📄 sysv init 2.6 的开机过程.htm
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# If there was a failure, drop into single-user mode.
#
# NOTE: "failure" is defined as exiting with a return code of
# 2 or larger. A return code of 1 indicates that file system
# errors were corrected but that the boot may proceed.
if [ $? -gt 1 ]
then
# Surprise! Re-directing from a HERE document (as in
# "cat << EOF") won't work, because the root is read-only.
echo
echo "fsck failed. Please repair manually and reboot. Please note"
echo "that the root file system is currently mounted read-only. To"
echo "remount it read-write:"
echo
echo " bash# mount -n -o remount,rw /"
echo
echo "CONTROL-D will reboot the system."
echo
# Start a single user shell on the console
/sbin/sulogin /dev/console
sync
reboot
fi
echo
else
echo "*** ERROR! Cannot fsck because root is not read-only!"
echo
fi
else
echo "*** Fast boot ... skipping disk checks"
echo
fi</pre>
<pre># Remount the root file system in read-write mode.
mount -n -o remount,rw /</pre>
<pre># Load the appropriate modules.
if [ -x /etc/init.d/modules ]
then
/etc/init.d/modules
fi</pre>
<pre># Remove /etc/mtab*, /etc/rmtab, /etc/nologin and /fastboot.
rm -f /etc/mtab* /etc/nologin /fastboot /etc/rmtab</pre>
<pre># update /etc/psdatabase
psupdate 2> /dev/null
# or
#ps -U 2> /dev/null</pre>
<pre># Mount local file systems in /etc/fstab.
echo "Mounting local file systems..."
mount -avt nonfs</pre>
<pre># Execute swapon command again, in case we want to swap to
# a file on a now mounted filesystem.
swapon -a 2>/dev/null</pre>
<pre># Setup the network interfaces. Note that /var/run and /var/lock
# are cleaned up after this, so don't put anything in the "network"
# script that leave a pidfile or a lockfile.
if [ -x /etc/init.d/network ]
then
/etc/init.d/network
fi</pre>
<pre># Set hostname.
# If there's no /etc/HOSTNAME, fall back on this default:
if [ ! -r /etc/HOSTNAME ]; then
echo "Henry.Dorm10.NCTU.edu.tw" > /etc/HOSTNAME
fi
cat /etc/HOSTNAME | cut -f1 -d . > /etc/hostname
hostname --file /etc/hostname</pre>
<pre># Now that TCP/IP is configured, mount the NFS file systems in /etc/fstab.
echo "Mounting remote file systems..."
mount -a -t nfs</pre>
<pre># Update all the shared library links automatically
echo "Update /etc/ld.so.cache and all the shared library links."
/sbin/ldconfig</pre>
<pre># Set GMT="-u" if your system clock is set to GMT, and GMT=""
# if not.
GMT=""
# Set and adjust the CMOS clock.
clock -s $GMT
if [ ! -f /etc/adjtime ]
then
echo "0.0 0 0.0" > /etc/adjtime
fi
clock -a $GMT</pre>
<pre># Now that /usr/lib/zoneinfo should be available, announce the local time.
echo
echo "Local time: `date`"
echo</pre>
<pre># Wipe /tmp (and don't erase `lost+found', `quota.user' or `quota.group')!
# Note that files _in_ lost+found _are_ deleted.
echo -n "Cleaning up /tmp, /var/run and /var/lock... "
( cd /tmp && \
find . \
! -name .\
! \( -name lost+found -uid 0 \) \
! \( -name quota.user -uid 0 \) \
! \( -name quota.group -uid 0 \) \
-depth -exec rm -rf -- {} \; )
# Clean up any stale locks.
( cd /var/lock && find . -type f -exec rm -f -- {} \; )
# Clean up /var/run and create /var/run/utmp so that we can login.
( cd /var/run && find . ! -type d -exec rm -f -- {} \; )
: > /var/run/utmp
echo "done."</pre>
<pre># Run the package-specific boot scripts in /etc/rc.boot.
run-parts /etc/rc.boot
# Set pseudo-terminal access permissions.
chmod 666 /dev/tty[pqrstuvwxyzabcde]*
chown root.tty /dev/tty[pqrstuvwxyzabcde]*</pre>
<pre># Setup the /etc/issue.net to reflect the current kernel level:
cat /etc/issue > /etc/issue.net
uname -a >> /etc/issue.net
echo >> /etc/issue.net</pre>
<pre>touch /etc/motd</pre>
<pre># and startup powerd
echo "Start up the genpowerd" ; /sbin/genpowerd /dev/UPS henry</pre>
<pre>--------------------- --------------------- ---------------------
这下我们的 /etc/init.d/boot 跑完了, 依照 /etc/inittab
的设定, 是跑 runlevel=3, 执行 /etc/init.d/rc 3 这个指令。</pre>
<pre>/etc/init.d/rc 是一个不错 (聪明？) 的 shell script,
我们来介绍一下它的运作方式。</pre>
<pre>在 SysV init 2.6 所用的 /etc/ 下, 除了 init.d/ 及
boot/ 这两个子目录外, 尚有:</pre>
<pre>drwxr-xr-x 2 root 1024 May 28 09:08 rc0.d/
drwxr-xr-x 2 root 1024 May 28 09:08 rc1.d/
drwxr-xr-x 2 root 1024 May 29 09:54 rc2.d/
drwxr-xr-x 2 root 1024 May 28 09:08 rc3.d/
drwxr-xr-x 2 root 1024 May 28 09:08 rc4.d/
drwxr-xr-x 2 root 1024 May 28 09:08 rc5.d/
drwxr-xr-x 2 root 1024 May 28 09:08 rc6.d/</pre>
<pre>这七个子目录, 我们以 rc3.d 来作□例:</pre>
<pre># dir rc3.d/
S20cron -> ../init.d/cron*
S20gpm -> ../init.d/gpm*
S20httpd -> ../init.d/httpd*
S20innbbsd -> ../init.d/innbbsd*
S20ip_acct -> ../init.d/ip_acct*
S20lpd -> ../init.d/lpd*
S20netbase -> ../init.d/netbase*
S20netstd_misc -> ../init.d/netstd_misc*
S20nfs -> ../init.d/nfs*
S20quota -> ../init.d/quota*
S30sendmail -> ../init.d/sendmail*
S30syslogd -> ../init.d/syslogd*</pre>
<pre>这些都是一个一个的 symbolic link 到 /etc/init.d/ 下的 script,
其中 S20 是一种控制说明, S 是表示 start (K 是表示 kill), 20
这个数字表示它们的执行顺序 (20 比 30 先执行, 同数字则照字母
顺序即可)。</pre>
<pre>/etc/init.d/rc 就是照给定的 runlevel 数字, 去对应的目录看这些
东西来决定要跑那些 script.</pre>
<pre>那麽, init.d/ 下的那些 script 又是怎麽回事呢？
我们来看一下好了:</pre>
<pre>root@Henry:/etc# dir init.d/
total 45
-rwxr-xr-x 1 root 5231 May 28 17:47 boot*
-rwxr-xr-x 1 root 290 May 28 09:08 cron*
-rwxr-xr-- 1 root 2250 May 29 01:29 genpowerfail*
-rwxr-xr-x 1 root 283 May 28 06:41 gpm*
-rwxr-xr-x 1 root 707 Feb 29 20:17 halt*
-rwxr-xr-x 1 root 718 May 28 06:27 httpd*
-rwxr-xr-x 1 root 494 May 28 07:05 innbbsd*
-rwxr-x--- 1 root 333 May 28 07:12 ip_acct*
-rwxr-xr-x 1 root 343 May 28 06:35 lpd*
-rwxr-xr-x 1 root 500 May 28 05:25 modules*
-rwxr-xr-x 1 root 699 May 28 06:12 netbase*
-rwxr-xr-x 1 root 391 Mar 19 10:32 netstd_init*
-rwxr-xr-x 1 root 598 May 29 09:54 netstd_misc*
-rwxr-xr-x 1 root 1372 May 29 10:05 network*
-rwxr-xr-x 1 root 1208 May 28 05:36 nfs*
-rwxr-xr-x 1 root 1258 Dec 28 08:02 powerfail*
-rwxr-x--- 1 root 891 May 28 06:45 quota*
-rwxr-xr-x 1 root 2928 Jan 4 19:59 rc*
-rwxr-xr-x 1 root 653 Feb 29 20:17 reboot*
-rwxr-xr-x 1 root 696 May 28 07:34 sendmail*
-rwxr-xr-x 1 root 527 Mar 20 00:44 single*
-rwxr-xr-x 1 root 1078 Dec 28 08:21 skeleton*
-rwxr-xr-x 1 root 640 May 29 08:21 syslogd*</pre>
<pre>呵呵, 没想到有这麽多吧？一个提供比较多服务的工作站, 大概
就需要这些。 除了 boot, rc, network, modules 是我们介绍
过的之外, 其他都是给 /etc/rc[0-6].d/ 做 symbolic link 用
去了。</pre>
<pre>OK, 我叫一个 script 出来给大家看:</pre>
<pre>-------[/etc/init.d/netbase]----------------------------
#!/bin/sh
#
# Start networking daemons.</pre>
<pre>test -f /usr/sbin/rpc.portmap || exit 0</pre>
<pre>case "$1" in
start)
echo -n "Starting base networking daemons: "
echo -n "rpc.portmap "
start-stop-daemon --start --quiet --exec /usr/sbin/rpc.portmap
echo -n "xinetd "
start-stop-daemon --start --quiet --exec /usr/sbin/xinetd
echo
;;
stop)
start-stop-daemon --stop --quiet --oknodo --exec /usr/sbin/xinetd
start-stop-daemon --stop --quiet --oknodo --exec /usr/sbin/rpc.portmap
killall -9 slattach 2>/dev/null || exit 0
;;
reload)
start-stop-daemon --stop --oknodo --signal 10 --exec /usr/sbin/xinetd
;;
*)
echo "Usage: /etc/init.d/netbase {start|stop|reload}"
exit 1
;;
esac</pre>
<pre>exit 0</pre>
<pre>-------[end]-----------------------------------------------------------------</pre>
<pre>其中 start-stop-daemon 是一个 perl script, 参数 --start 是跑它去启动
那个 daemon (例如 xinetd), 参数 --stop 是叫它杀掉那个 daemon。 一般
而言, 如果给的 signal 对的话 (预设值是 9, SIGKILL), 尚可使该 daemon
reload 一次它的设定档 (以 xinetd 为例是 10, SIGUSR1), 而通常都是给
1, SIGHUP。</pre>
<pre>S20netbase 这个 symbolic link 会使得 /etc/init.d/rc 去启动它, 也就是
跑 '/etc/init.d/netbase start', 使得 rpc.portmap 及 xinetd 执行起来,
就达到我们所要求的。</pre>
<pre>其他如 lpd、gpm、httpd、nfs、也是如此。 补充一点的是, nfs 类的 daemon
一定得在 rpc.portmap 跑起来之後才能正确动作 (因为 nfs 也是一种 rpc),
但在此 S20netbase 会比 S20nfs 先跑 (考虑字母顺序), 所以看起来没有什麽
问题。 注意一下执行顺序是很重要的事。</pre>
<pre>在此再补充一点, debian 有一个工具程式 update-rc.d 很有用:</pre>
<pre>-----------[man update-rc.d]-------------------------------------
NAME
update-rc.d - install and remove System-V style init
script links</pre>
<pre>SYNOPSIS
update-rc.d <basename> remove</pre>
<pre> update-rc.d <basename> defaults [ <codenumber> | <startco-
denumber> <stopcodenumber> ]</pre>
<pre> update-rc.d <basename> start | stop <codenumber> <run-
level> [ <runlevel> [ <runlevel> [...]]] .</pre>
<pre>----------[end of part]------------------------------------------</pre>
<pre>它会帮助你把新造好的 script 加入 /etc/rc[0-6].d/ 中的 symbolic
link. 如果是 defaults, 则在 rc[2-5].d/ 下造 S20xxxxx, rc[016].d/
下造 K20xxxxx 的 symbolic link, 不错吧？</pre>
<pre>好, /etc/init.d/rc 3 也跑完了, 再来就是开 console
了。 依照 inittab 的设定, 是在 tty1 ~ tty6 开六个
virtual console, 所以我们可以用 atl-f1 到 f6 来切
换 virtual console 的操作。 login 之後, 我们会看
到下面的 process:</pre>
<pre>root@Henry:/etc# ps ax |grep getty
165 v02 S 0:00 /sbin/agetty 19200 tty2
166 v03 S 0:00 /sbin/agetty 19200 tty3
167 v04 S 0:00 /sbin/agetty 19200 tty4
168 v05 S 0:00 /sbin/agetty 19200 tty5
169 v06 S 0:00 /sbin/agetty 19200 tty6</pre>
<pre>因为我们已经 login 了, 用掉 tty1 了, 所以看不到 tty1
在跑 agetty.</pre>
<pre>有关 SysV init 2.6 版就先讲到这□, 大家有没有什麽问题？</pre>
<pre>接下来要谈到的是 UPS 和 powerd 的连接方式, 我们先休息
十分钟。</pre>
<p><a href="../hkbx!.htm"><strong><big>返回“新客补习”</big></strong></a></p>
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