rc.initdiskless revision 179014
1#!/bin/sh 2# 3# Copyright (c) 1999 Matt Dillon 4# All rights reserved. 5# 6# Redistribution and use in source and binary forms, with or without 7# modification, are permitted provided that the following conditions 8# are met: 9# 1. Redistributions of source code must retain the above copyright 10# notice, this list of conditions and the following disclaimer. 11# 2. Redistributions in binary form must reproduce the above copyright 12# notice, this list of conditions and the following disclaimer in the 13# documentation and/or other materials provided with the distribution. 14# 15# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25# SUCH DAMAGE. 26# 27# $FreeBSD: head/etc/rc.initdiskless 179014 2008-05-15 11:00:23Z bms $ 28 29# On entry to this script the entire system consists of a read-only root 30# mounted via NFS. The kernel has run BOOTP and configured an interface 31# (otherwise it would not have been able to mount the NFS root!) 32# 33# We use the contents of /conf to create and populate memory filesystems 34# that are mounted on top of this root to implement the writable 35# (and host-specific) parts of the root filesystem, and other volatile 36# filesystems. 37# 38# The hierarchy in /conf has the form /conf/T/M/ where M are directories 39# for which memory filesystems will be created and filled, 40# and T is one of the "template" directories below: 41# 42# base universal base, typically a replica of the original root; 43# default secondary universal base, typically overriding some 44# of the files in the original root; 45# ${ipba} where ${ipba} is the assigned broadcast IP address 46# bcast/${ipba} same as above 47# ${class} where ${class} is a list of directories supplied by 48# bootp/dhcp through the T134 option. 49# ${ipba} and ${class} are typicall used to configure features 50# for group of diskless clients, or even individual features; 51# ${ip} where ${ip} is the machine's assigned IP address, typically 52# used to set host-specific features; 53# ip/${ip} same as above 54# 55# Template directories are scanned in the order they are listed above, 56# with each sucessive directory overriding (merged into) the previous one; 57# non-existing directories are ignored. The subdirectory forms exist to 58# help keep the top level /conf managable in large installations. 59# 60# The existence of a directory /conf/T/M causes this script to create a 61# memory filesystem mounted as /M on the client. 62# 63# Some files in /conf have special meaning, namely: 64# 65# Filename Action 66# ---------------------------------------------------------------- 67# /conf/T/M/remount 68# The contents of the file is a mount command. E.g. if 69# /conf/1.2.3.4/foo/remount contains "mount -o ro /dev/ad0s3", 70# then /dev/ad0s3 will be be mounted on /conf/1.2.3.4/foo/ 71# 72# /conf/T/M/remount_optional 73# If this file exists, then failure to execute the mount 74# command contained in /conf/T/M/remount is non-fatal. 75# 76# /conf/T/M/diskless_remount 77# The contents of the file points to an NFS filesystem, 78# possibly followed by mount_nfs options. If the server name 79# is omitted, the script will prepend the root path used when 80# booting. E.g. if you booted from foo.com:/path/to/root, 81# an entry for /conf/base/etc/diskless_remount could be any of 82# foo.com:/path/to/root/etc 83# /etc -o ro 84# Because mount_nfs understands ".." in paths, it is 85# possible to mount from locations above the NFS root with 86# paths such as "/../../etc". 87# 88# /conf/T/M/md_size 89# The contents of the file specifies the size of the memory 90# filesystem to be created, in 512 byte blocks. 91# The default size is 10240 blocks (5MB). E.g. if 92# /conf/base/etc/md_size contains "30000" then a 15MB MFS 93# will be created. In case of multiple entries for the same 94# directory M, the last one in the scanning order is used. 95# NOTE: If you only need to create a memory filesystem but not 96# initialize it from a template, it is preferrable to specify 97# it in fstab e.g. as "md /tmp mfs -s=30m,rw 0 0" 98# 99# /conf/T/SUBDIR.cpio.gz 100# The file is cpio'd into /SUBDIR (and a memory filesystem is 101# created for /SUBDIR if necessary). The presence of this file 102# prevents the copy from /conf/T/SUBDIR/ 103# 104# /conf/T/SUBDIR.remove 105# The list of paths contained in the file are rm -rf'd 106# relative to /SUBDIR. 107# 108# /conf/diskless_remount 109# Similar to /conf/T/M/diskless_remount above, but allows 110# all of /conf to be remounted. This can be used to allow 111# multiple roots to share the same /conf. 112# 113# 114# You will almost universally want to create the following files under /conf 115# 116# File Content 117# ---------------------------- ---------------------------------- 118# /conf/base/etc/md_size size of /etc filesystem 119# /conf/base/etc/diskless_remount "/etc" 120# /conf/default/etc/rc.conf generic diskless config parameters 121# /conf/default/etc/fstab generic diskless fstab e.g. like this 122# 123# foo:/root_part / nfs ro 0 0 124# foo:/usr_part /usr nfs ro 0 0 125# foo:/home_part /home nfs rw 0 0 126# md /tmp mfs -s=30m,rw 0 0 127# md /var mfs -s=30m,rw 0 0 128# proc /proc procfs rw 0 0 129# 130# plus, possibly, overrides for password files etc. 131# 132# NOTE! /var, /tmp, and /dev will be typically created elsewhere, e.g. 133# as entries in the fstab as above. 134# Those filesystems should not be specified in /conf. 135# 136# (end of documentation, now get to the real code) 137 138dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null` 139 140# DEBUGGING 141# log something on stdout if verbose. 142o_verbose=0 # set to 1 or 2 if you want more debugging 143log() { 144 [ ${o_verbose} -gt 0 ] && echo "*** $* ***" 145 [ ${o_verbose} -gt 1 ] && read -p "=== Press enter to continue" foo 146} 147 148# chkerr: 149# 150# Routine to check for error 151# 152# checks error code and drops into shell on failure. 153# if shell exits, terminates script as well as /etc/rc. 154# if remount_optional exists under the mountpoint, skip this check. 155# 156chkerr() { 157 lastitem () ( n=$(($# - 1)) ; shift $n ; echo $1 ) 158 mountpoint="$(lastitem $2)" 159 [ -r $mountpoint/remount_optional ] && ( echo "$2 failed: ignoring due to remount_optional" ; return ) 160 case $1 in 161 0) 162 ;; 163 *) 164 echo "$2 failed: dropping into /bin/sh" 165 /bin/sh 166 # RESUME 167 ;; 168 esac 169} 170 171# The list of filesystems to umount after the copy 172to_umount="" 173 174handle_remount() { # $1 = mount point 175 local nfspt mountopts b 176 b=$1 177 log handle_remount $1 178 [ -d $b -a -f $b/diskless_remount ] || return 179 read nfspt mountopts < $b/diskless_remount 180 log "nfspt ${nfspt} mountopts ${mountopts}" 181 # prepend the nfs root if not present 182 [ `expr "$nfspt" : '\(.\)'` = "/" ] && nfspt="${nfsroot}${nfspt}" 183 mount_nfs $mountopts $nfspt $b 184 chkerr $? "mount_nfs $nfspt $b" 185 to_umount="$b ${to_umount}" 186} 187 188# Create a generic memory disk 189# 190mount_md() { 191 /sbin/mdmfs -S -i 4096 -s $1 -M md $2 192} 193 194# Create the memory filesystem if it has not already been created 195# 196create_md() { 197 [ "x`eval echo \\$md_created_$1`" = "x" ] || return # only once 198 if [ "x`eval echo \\$md_size_$1`" = "x" ]; then 199 md_size=10240 200 else 201 md_size=`eval echo \\$md_size_$1` 202 fi 203 log create_md $1 with size $md_size 204 mount_md $md_size /$1 205 /bin/chmod 755 /$1 206 eval md_created_$1=created 207} 208 209# DEBUGGING 210# 211# set -v 212 213# Figure out our interface and IP. 214# 215bootp_ifc="" 216bootp_ipa="" 217bootp_ipbca="" 218class="" 219if [ ${dlv:=0} -ne 0 ] ; then 220 iflist=`ifconfig -l` 221 for i in ${iflist} ; do 222 set -- `ifconfig ${i}` 223 while [ $# -ge 1 ] ; do 224 if [ "${bootp_ifc}" = "" -a "$1" = "inet" ] ; then 225 bootp_ifc=${i} ; bootp_ipa=${2} ; shift 226 fi 227 if [ "${bootp_ipbca}" = "" -a "$1" = "broadcast" ] ; then 228 bootp_ipbca=$2; shift 229 fi 230 shift 231 done 232 if [ "${bootp_ifc}" != "" ] ; then 233 break 234 fi 235 done 236 # Get the values passed with the T134 bootp cookie. 237 class="`/sbin/sysctl -qn kern.bootp_cookie`" 238 239 echo "Interface ${bootp_ifc} IP-Address ${bootp_ipa} Broadcast ${bootp_ipbca} ${class}" 240fi 241 242log Figure out our NFS root path 243# 244set -- `mount -t nfs` 245while [ $# -ge 1 ] ; do 246 if [ "$2" = "on" -a "$3" = "/" ]; then 247 nfsroot="$1" 248 break 249 fi 250 shift 251done 252 253# The list of directories with template files 254templates="base default" 255if [ -n "${bootp_ipbca}" ]; then 256 templates="${templates} ${bootp_ipbca} bcast/${bootp_ipbca}" 257fi 258if [ -n "${class}" ]; then 259 templates="${templates} ${class}" 260fi 261if [ -n "${bootp_ipa}" ]; then 262 templates="${templates} ${bootp_ipa} ip/${bootp_ipa}" 263fi 264 265# If /conf/diskless_remount exists, remount all of /conf. 266handle_remount /conf 267 268# Resolve templates in /conf/base, /conf/default, /conf/${bootp_ipbca}, 269# and /conf/${bootp_ipa}. For each subdirectory found within these 270# directories: 271# 272# - calculate memory filesystem sizes. If the subdirectory (prior to 273# NFS remounting) contains the file 'md_size', the contents specified 274# in 512 byte sectors will be used to size the memory filesystem. Otherwise 275# 8192 sectors (4MB) is used. 276# 277# - handle NFS remounts. If the subdirectory contains the file 278# diskless_remount, the contents of the file is NFS mounted over 279# the directory. For example /conf/base/etc/diskless_remount 280# might contain 'myserver:/etc'. NFS remounts allow you to avoid 281# having to dup your system directories in /conf. Your server must 282# be sure to export those filesystems -alldirs, however. 283# If the diskless_remount file contains a string beginning with a 284# '/' it is assumed that the local nfsroot should be prepended to 285# it before attemping to the remount. This allows the root to be 286# relocated without needing to change the remount files. 287# 288log "templates are ${templates}" 289for i in ${templates} ; do 290 for j in /conf/$i/* ; do 291 [ -d $j ] || continue 292 293 # memory filesystem size specification 294 subdir=${j##*/} 295 [ -f $j/md_size ] && eval md_size_$subdir=`cat $j/md_size` 296 297 # remount. Beware, the command is in the file itself! 298 if [ -f $j/remount ]; then 299 nfspt=`/bin/cat $j/remount` 300 $nfspt $j 301 chkerr $? "$nfspt $j" 302 to_umount="$j ${to_umount}" # XXX hope it is really a mount! 303 fi 304 305 # NFS remount 306 handle_remount $j 307 done 308done 309 310# - Create all required MFS filesystems and populate them from 311# our templates. Support both a direct template and a dir.cpio.gz 312# archive. Support dir.remove files containing a list of relative 313# paths to remove. 314# 315# The dir.cpio.gz form is there to make the copy process more efficient, 316# so if the cpio archive is present, it prevents the files from dir/ 317# from being copied. 318 319for i in ${templates} ; do 320 for j in /conf/$i/* ; do 321 subdir=${j##*/} 322 if [ -d $j -a ! -f $j.cpio.gz ]; then 323 create_md $subdir 324 cp -Rp $j/ /$subdir 325 fi 326 done 327 for j in /conf/$i/*.cpio.gz ; do 328 subdir=${j%*.cpio.gz} 329 subdir=${subdir##*/} 330 if [ -f $j ]; then 331 create_md $subdir 332 echo "Loading /$subdir from cpio archive $j" 333 (cd / ; /rescue/tar -xpf $j) 334 fi 335 done 336 for j in /conf/$i/*.remove ; do 337 subdir=${j%*.remove} 338 subdir=${subdir##*/} 339 if [ -f $j ]; then 340 # doubly sure it is a memory disk before rm -rf'ing 341 create_md $subdir 342 (cd /$subdir; rm -rf `/bin/cat $j`) 343 fi 344 done 345done 346 347# umount partitions used to fill the memory filesystems 348[ -n "${to_umount}" ] && umount $to_umount 349