Linux autofs

# $Id: auto.master,v 1.2 1997/10/06 21:52:03 hpa Exp $
# Sample auto.master file
# Format of this file:
# mount point map options
# For details of the format look at autofs(8).
/mnt	/etc/auto.misc	--timeout 20

# $Id: auto.misc,v 1.2 1997/10/06 21:52:04 hpa Exp $
# This is an automounter map and it has the following format
# key [ -mount-options-separated-by-comma ] location
# Details may be found in the autofs(5) manpage

#kernel		-ro,soft,intr		ftp.kernel.org:/pub/linux
cd		-fstype=iso9660,ro	:/dev/cdrom

# the following entries are samples to pique your imagination
fl		-fstype=auto		:/dev/fd0
#floppy		-fstype=ext2		:/dev/fd0
#e2floppy	-fstype=ext2		:/dev/fd0
#jaz		-fstype=ext2		:/dev/sdc1

This file controls the devices to be mounted and specifies the directory used for that device.

The autofs startup script

#! /bin/bash
#
#       $Id: rc.autofs,v 1.4 1998/11/03 21:05:18 hpa Exp $
#
#	/etc/rc.d/init.d/autofs
#
#	rc file for automount using a Sun-style "master map".
#	We first look for a local /etc/auto.master, then a YP
#	map with that name
#
# chkconfig: - 72 08
# description: automatically mounts filesystems when you use \
#   them, and unmounts them later when you are not using them.
# processname: automount
#   Note that there may be multiple processes names automount
# config: /etc/auto.master
#   Note that all other config files are automatically reloaded
#   and may be different on different systems; we can ignore them
#   here

# Source function library.
. /etc/rc.d/init.d/functions

test -f /usr/sbin/automount || exit 0

#
# 	We can add local options here
#	e.g. localoptions='rsize=8192,wsize=8192'
#
localoptions=''

#
#	This function will build a list of automount commands to execute in
#	order #	to activate all the mount points. It is used to figure out
#	the difference of automount points in case of a reload
#
function getmounts()
{
#
#	Check for local maps to be loaded
#
if [ -f /etc/auto.master ] ; then
    cat /etc/auto.master | sed -e '/^#/d' -e '/^$/d'| (
	while read dir map options ;  do
	    if [ ! -z "$dir" -a ! -z "$map" \
			-a x`echo "$map" | cut -c1` != 'x-' ]
	    then
 		# special: treat -t or --timeout (or any reasonable derivative)
 		# specially, since it can't be made a normal mount option.
 		if echo $options | grep -- '-t' >/dev/null 2>&1 ; then
 		    mountoptions="--timeout $(echo $options | \
 		      sed 's/^.*-t\(imeout\)*[ \t]*\([0-9][0-9]*\).*$/\2/g')"
 		fi
 		options=`echo "$options" | sed -e '
 		  s/--*t\(imeout\)*[ \t]*[0-9][0-9]*//g
 		  s/\(^\|[ \t]\)-/\1/g'`
		basecommand="/usr/sbin/automount $mountoptions $dir"
		maptype=
		if echo $map | grep -- ':' ; then
		    maptype=`echo $map | cut -d ':' -f 1`
		    map=`echo $map | cut -d ':' -f 2-`
		fi
		case $map in
		    /*)	
		        if [ -n "$maptype" ] ; then
			    echo "$basecommand $maptype $map $options $localoptions"
			else
			    if [ -x $map ]; then
			        echo "$basecommand program $map $options $localoptions"
			    elif [ -f $map ]; then
			        echo "$basecommand file $map $options $localoptions"
			    else
			        echo "$basecommand `basename $map` $options $localoptions"
			    fi
			fi
			;;
		    *)
		        if [ -n "$maptype" ] ; then
			    echo "$basecommand $maptype $map $options $localoptions"
			else
			    if [ -f /etc/$map ] ; then
			        echo "$basecommand file /etc/$map $options $localoptions"
			    else
			        echo "$basecommand yp $map $options $localoptions"
			    fi
			fi
			;;
		esac
		unset basecommand
	    fi
	done
    )
else
#
#	Next to check for YellowPage maps to be loaded
#
  if [ -e /usr/bin/ypcat ] && [ `ypcat -k auto.master 2>/dev/null | wc -l` -gt 0 ]
  then
    ypcat -k auto.master | (
	while read dir map options
	do
	    if [ ! -z "$dir" -a ! -z "$map" \
			-a x`echo "$map" | cut -c1` != 'x-' ]
	    then
		map=`echo "$map" | sed -e 's/^auto_/auto./'`
		if echo $options | grep -- '-t' >/dev/null 2>&1 ; then
		    mountoptions="--timeout $(echo $options | \
		      sed 's/^.*-t\(imeout\)*[ \t]*\([0-9][0-9]*\).*$/\2/g')"
		fi
		options=`echo "$options" | sed -e '
		  s/--*t\(imeout\)*[ \t]*[0-9][0-9]*//g
		  s/\(^\|[ \t]\)-/\1/g'`
		echo "/usr/sbin/automount $mountoptions $dir yp $map $options $localoptions"
	    fi
	done
    )
  fi
fi
}

#
#	See how we were called.
#
case "$1" in
  start)
	# Check if the automounter is already running?
	if [ ! -f /var/lock/subsys/autofs ]; then
	    echo 'Starting automounter: '
	    getmounts | sh
	    touch /var/lock/subsys/autofs
	fi
	;;
  stop)
	kill -TERM $(/sbin/pidof /usr/sbin/automount)
	rm -f /var/lock/subsys/autofs
	;;
  reload|restart)
	if [ ! -f /var/lock/subsys/autofs ]; then
		echo "Automounter not running"
		exit 1
	fi
	echo "Checking for changes to /etc/auto.master ...."
	TMP1=`mktemp /tmp/autofs.XXXXXX` || { echo "could not make temp file" >&2; exit 1; }
	TMP2=`mktemp /tmp/autofs.XXXXXX` || { echo "could not make temp file" >&2; exit 1; }
	getmounts >$TMP1
	ps axw|grep "[0-9]:[0-9][0-9] /usr/sbin/automount " | (
	    while read pid tt stat time command; do
		echo "$command" >>$TMP2
		if ! grep -q "^$command" $TMP2; then
			kill -USR2 $pid
			echo "Stop $command"
		fi
	    done
	)
	cat $TMP1 | ( while read x; do
		if ! grep -q "^$x" $TMP2; then
			$x
			echo "Start $x"
		fi
        done )
	rm -f $TMP1 $TMP2
	;;
  status)
	echo "Configured Mount Points:"
	getmounts
	echo ""
	echo "Active Mount Points:"
	ps axw|grep "[0-9]:[0-9][0-9] /usr/sbin/automount " | (
		while read pid tt stat time command; do echo $command; done
	)
	;;
  *)
	echo "Usage: /etc/rc.d/init.d/autofs {start|stop|restart|reload|status}"
	exit 1
esac

exit 0