freebsd-dev/etc/rc.initdiskless

#!/bin/sh
#
# Copyright (c) 1999  Matt Dillon
# 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 AUTHOR 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 AUTHOR 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: initdiskless
# KEYWORD: FreeBSD

 
# On entry to this script the entire system consists of a read-only root
# mounted via NFS.  We use the contents of /conf to create and populate
# memory filesystems.  The kernel has run BOOTP and configured an interface
# (otherwise it would not have been able to mount the NFS root!)
#
# The following directories are scanned.  Each sucessive directory overrides
# (is merged into) the previous one.
#
#	/conf/base		universal base
#	/conf/default		modified by a secondary universal base
#	/conf/${ipba}		modified based on the assigned broadcast IP
#	/conf/${ip}		modified based on the machine's assigned IP
#
# Each of these directories may contain any number of subdirectories which
# represent directories in / on the diskless machine.  The existance of
# these subdirectories causes this script to create a MEMORY FILESYSTEM for
# /<sub_directory_name>.  For example, if /conf/base/etc exists then a
# memory filesystem will be created for /etc.
#
# If a subdirectory contains the file 'diskless_remount' the contents of
# the file is used to remount the subdirectory prior to it being copied to
# the memory filesystem.  For example, if /conf/base/etc/diskless_remount
# contains the string 'my.server.com:/etc' then my.server.com:/etc will be
# mounted in place of the subdirectory.  This allows you to avoid making
# duplicates of system directories in /conf.
#
# If a subdirectory contains the file 'md_size', the contents of the
# file is used to determine the size of the memory filesystem, in 512
# byte sectors.  The default is 8192 (4MB).  You only have to specify an
# md_size if the default doesn't work for you (i.e. if it is too big or
# too small).  Note that in -current the default is 4096 (2MB).  For
# example, /conf/base/etc/md_size might contain '16384'.
#
# If /conf/<special_dir>/SUBDIR.cpio.gz exists, the file is cpio'd into
# the specified /SUBDIR (and a memory filesystem is created for /SUBDIR
# if necessary).
#
# If /conf/<special_dir>/SUBDIR.remove exists, the file contains a list
# of paths which are rm -rf'd relative to /SUBDIR.
#
# You will almost universally want to create a /conf/base/etc containing
# a diskless_remount and possibly an md_size file.  You will then almost
# universally want to override rc.conf, rc.local, and fstab by creating
# /conf/default/etc/{rc.conf,rc.local,fstab}.  Your fstab should be sure
# to mount a /usr... typically an NFS readonly /usr.
#
# NOTE!  rc.diskless2 will create /var, /tmp, and /dev.  Those filesystems
# should not be specified in /conf.  At least not yet.

dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null`
[ ${dlv:=0} -eq 0 ] && exit 0

# chkerr:
#
# Routine to check for error
#
#	checks error code and drops into shell on failure.
#	if shell exits, terminates script as well as /etc/rc.
#
chkerr() {
    case $1 in
    0)
	;;
    *)
	echo "$2 failed: dropping into /bin/sh"
	/bin/sh
	# RESUME
	;;
    esac
}

# Create a generic memory disk
#
mount_md() {
    /sbin/mdmfs -i 4096 -s $1 -M md $2
}

# Create the memory filesystem if it has not already been created
#
create_md() {
    if [ "x`eval echo \\$md_created_$1`" = "x" ]; then
	if [ "x`eval echo \\$md_size_$1`" = "x" ]; then
	    md_size=4096
	else
	    md_size=`eval echo \\$md_size_$1`
	fi
	mount_md $md_size /$1
	/bin/chmod 755 /$1
	eval md_created_$1=created
    fi
}

# DEBUGGING
#
# set -v

# Figure out our interface and IP.
#
bootp_ifc=""
bootp_ipa=""
bootp_ipbca=""
iflist=`ifconfig -l`
for i in ${iflist} ; do
    set `ifconfig ${i}`
    while [ $# -ge 1 ] ; do
        if [ "${bootp_ifc}" = "" -a "$1" = "inet" ] ; then
            bootp_ifc=${i} ; bootp_ipa=${2} ; shift
        fi
        if [ "${bootp_ipbca}" = "" -a "$1" = "broadcast" ] ; then
            bootp_ipbca=$2; shift
        fi
        shift
    done
    if [ "${bootp_ifc}" != "" ] ; then
        break
    fi
done
echo "Interface ${bootp_ifc} IP-Address ${bootp_ipa} Broadcast ${bootp_ipbca}"

# Figure out our NFS root path
# 
set `mount -t nfs`
while [ $# -ge 1 ] ; do
    if [ "$2" = "on" -a "$3" = "/" ]; then
	nfsroot="$1"
	break
    fi
    shift
done

# Resolve templates in /conf/base, /conf/default, /conf/${bootp_ipbca},
# and /conf/${bootp_ipa}.  For each subdirectory found within these 
# directories:
#
# - calculate memory filesystem sizes.  If the subdirectory (prior to
#   NFS remounting) contains the file 'md_size', the contents specified
#   in 512 byte sectors will be used to size the memory filesystem.  Otherwise
#   8192 sectors (4MB) is used.
#
# - handle NFS remounts.  If the subdirectory contains the file
#   diskless_remount, the contents of the file is NFS mounted over
#   the directory.  For example /conf/base/etc/diskless_remount
#   might contain 'myserver:/etc'.  NFS remounts allow you to avoid
#   having to dup your system directories in /conf.  Your server must
#   be sure to export those filesystems -alldirs, however.
#   If the diskless_remount file contains a string beginning with a
#   '/' it is assumed that the local nfsroot should be prepended to
#   it before attemping to the remount.  This allows the root to be
#   relocated without needing to change the remount files.
#
for i in base default ${bootp_ipbca} ${bootp_ipa} ; do
    for j in /conf/$i/* ; do
	# memory filesystem size specification
	#
	subdir=${j##*/}
	if [ -d $j -a -f $j/md_size ]; then
	    eval md_size_$subdir=`cat $j/md_size`
	fi

	# NFS remount
	#
	if [ -d $j -a -f $j/diskless_remount ]; then
	    nfspt=`/bin/cat $j/diskless_remount`
	    if [ `expr "$nfspt" : '\(.\)'` = "/" ]; then
		nfspt="${nfsroot}${nfspt}"
	    fi
	    mount_nfs $nfspt $j
	    chkerr $? "mount_nfs $nfspt $j"
	fi
    done
done

# - Create all required MFS filesystems and populate them from
#   our templates.  Support both a direct template and a dir.cpio.gz
#   archive.  Support dir.remove files containing a list of relative
#   paths to remove.
#
# TODO:
#   + find a way to assign a 'group' identifier to a machine
#	so we can use group-specific configurations;

for i in base default ${bootp_ipbca} ${bootp_ipa} ; do
    for j in /conf/$i/* ; do
	subdir=${j##*/}
	if [ -d $j ]; then
	    create_md $subdir
	    cp -Rp $j/* /$subdir
	fi
    done
    for j in /conf/$i/*.cpio.gz ; do
	subdir=${j%*.cpio.gz}
	subdir=${subdir##*/}
	if [ -f $j ]; then
	    create_md $subdir
	    echo "Loading /$subdir from cpio archive $j"
	    (cd / ; /stand/gzip -d < $j | /stand/cpio --extract -d )
	fi
    done
    for j in /conf/$i/*.remove ; do
	subdir=${j%*.remove}
	subdir=${subdir##*/}
	if [ -f $j ]; then
	    # doubly sure it is a memory disk before rm -rf'ing
	    create_md $subdir
	    (cd /$subdir; rm -rf `/bin/cat $j`)
	fi
    done
done