#!/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. # # $FreeBSD$ # On entry to this script the entire system consists of a read-only root # mounted via NFS. The kernel has run BOOTP and configured an interface # (otherwise it would not have been able to mount the NFS root!) # # We use the contents of /conf to create and populate memory filesystems # that are mounted on top of this root to implement the writable # (and host-specific) parts of the root filesystem, and other volatile # filesystems. # # The hierarchy in /conf has the form /conf/T/M/ where M are directories # for which memory filesystems will be created and filled, # and T is one of the "template" directories below: # # base universal base, typically a replica of the original root; # default secondary universal base, typically overriding some # of the files in the original root; # ${ipba} where ${ipba} is the assigned broadcast IP address # bcast/${ipba} same as above # ${class} where ${class} is a list of directories supplied by # bootp/dhcp through the T134 option. # ${ipba} and ${class} are typicall used to configure features # for group of diskless clients, or even individual features; # ${ip} where ${ip} is the machine's assigned IP address, typically # used to set host-specific features; # ip/${ip} same as above # # Template directories are scanned in the order they are listed above, # with each sucessive directory overriding (merged into) the previous one; # non-existing directories are ignored. The subdirectory forms exist to # help keep the top level /conf managable in large installations. # # The existence of a directory /conf/T/M causes this script to create a # memory filesystem mounted as /M on the client. # # Some files in /conf have special meaning, namely: # # Filename Action # ---------------------------------------------------------------- # /conf/T/M/remount # The contents of the file is a mount command. E.g. if # /conf/1.2.3.4/foo/remount contains "mount -o ro /dev/ad0s3", # then /dev/ad0s3 will be be mounted on /conf/1.2.3.4/foo/ # # /conf/T/M/remount_optional # If this file exists, then failure to execute the mount # command contained in /conf/T/M/remount is non-fatal. # # /conf/T/M/diskless_remount # The contents of the file points to an NFS filesystem, # possibly followed by mount_nfs options. If the server name # is omitted, the script will prepend the root path used when # booting. E.g. if you booted from foo.com:/path/to/root, # an entry for /conf/base/etc/diskless_remount could be any of # foo.com:/path/to/root/etc # /etc -o ro # Because mount_nfs understands ".." in paths, it is # possible to mount from locations above the NFS root with # paths such as "/../../etc". # # /conf/T/M/md_size # The contents of the file specifies the size of the memory # filesystem to be created, in 512 byte blocks. # The default size is 10240 blocks (5MB). E.g. if # /conf/base/etc/md_size contains "30000" then a 15MB MFS # will be created. In case of multiple entries for the same # directory M, the last one in the scanning order is used. # NOTE: If you only need to create a memory filesystem but not # initialize it from a template, it is preferrable to specify # it in fstab e.g. as "md /tmp mfs -s=30m,rw 0 0" # # /conf/T/SUBDIR.cpio.gz # The file is cpio'd into /SUBDIR (and a memory filesystem is # created for /SUBDIR if necessary). The presence of this file # prevents the copy from /conf/T/SUBDIR/ # # /conf/T/SUBDIR.remove # The list of paths contained in the file are rm -rf'd # relative to /SUBDIR. # # /conf/diskless_remount # Similar to /conf/T/M/diskless_remount above, but allows # all of /conf to be remounted. This can be used to allow # multiple roots to share the same /conf. # # # You will almost universally want to create the following files under /conf # # File Content # ---------------------------- ---------------------------------- # /conf/base/etc/md_size size of /etc filesystem # /conf/base/etc/diskless_remount "/etc" # /conf/default/etc/rc.conf generic diskless config parameters # /conf/default/etc/fstab generic diskless fstab e.g. like this # # foo:/root_part / nfs ro 0 0 # foo:/usr_part /usr nfs ro 0 0 # foo:/home_part /home nfs rw 0 0 # md /tmp mfs -s=30m,rw 0 0 # md /var mfs -s=30m,rw 0 0 # proc /proc procfs rw 0 0 # # plus, possibly, overrides for password files etc. # # NOTE! /var, /tmp, and /dev will be typically created elsewhere, e.g. # as entries in the fstab as above. # Those filesystems should not be specified in /conf. # # (end of documentation, now get to the real code) dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null` # DEBUGGING # log something on stdout if verbose. o_verbose=0 # set to 1 or 2 if you want more debugging log() { [ ${o_verbose} -gt 0 ] && echo "*** $* ***" [ ${o_verbose} -gt 1 ] && read -p "=== Press enter to continue" foo } # chkerr: # # Routine to check for error # # checks error code and drops into shell on failure. # if shell exits, terminates script as well as /etc/rc. # if remount_optional exists under the mountpoint, skip this check. # chkerr() { lastitem () ( n=$(($# - 1)) ; shift $n ; echo $1 ) mountpoint="$(lastitem $2)" [ -r $mountpoint/remount_optional ] && ( echo "$2 failed: ignoring due to remount_optional" ; return ) case $1 in 0) ;; *) echo "$2 failed: dropping into /bin/sh" /bin/sh # RESUME ;; esac } # The list of filesystems to umount after the copy to_umount="" handle_remount() { # $1 = mount point local nfspt mountopts b b=$1 log handle_remount $1 [ -d $b -a -f $b/diskless_remount ] || return read nfspt mountopts < $b/diskless_remount log "nfspt ${nfspt} mountopts ${mountopts}" # prepend the nfs root if not present [ `expr "$nfspt" : '\(.\)'` = "/" ] && nfspt="${nfsroot}${nfspt}" mount_nfs $mountopts $nfspt $b chkerr $? "mount_nfs $nfspt $b" to_umount="$b ${to_umount}" } # Create a generic memory disk # mount_md() { /sbin/mdmfs -S -i 4096 -s $1 -M md $2 } # Create the memory filesystem if it has not already been created # create_md() { [ "x`eval echo \\$md_created_$1`" = "x" ] || return # only once if [ "x`eval echo \\$md_size_$1`" = "x" ]; then md_size=10240 else md_size=`eval echo \\$md_size_$1` fi log create_md $1 with size $md_size mount_md $md_size /$1 /bin/chmod 755 /$1 eval md_created_$1=created } # DEBUGGING # # set -v # Figure out our interface and IP. # bootp_ifc="" bootp_ipa="" bootp_ipbca="" class="" if [ ${dlv:=0} -ne 0 ] ; then 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 # Get the values passed with the T134 bootp cookie. class="`/sbin/sysctl -qn kern.bootp_cookie`" echo "Interface ${bootp_ifc} IP-Address ${bootp_ipa} Broadcast ${bootp_ipbca} ${class}" fi log Figure out our NFS root path # set -- `mount -t nfs` while [ $# -ge 1 ] ; do if [ "$2" = "on" -a "$3" = "/" ]; then nfsroot="$1" break fi shift done # The list of directories with template files templates="base default" if [ -n "${bootp_ipbca}" ]; then templates="${templates} ${bootp_ipbca} bcast/${bootp_ipbca}" fi if [ -n "${class}" ]; then templates="${templates} ${class}" fi if [ -n "${bootp_ipa}" ]; then templates="${templates} ${bootp_ipa} ip/${bootp_ipa}" fi # If /conf/diskless_remount exists, remount all of /conf. handle_remount /conf # 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. # log "templates are ${templates}" for i in ${templates} ; do for j in /conf/$i/* ; do [ -d $j ] || continue # memory filesystem size specification subdir=${j##*/} [ -f $j/md_size ] && eval md_size_$subdir=`cat $j/md_size` # remount. Beware, the command is in the file itself! if [ -f $j/remount ]; then nfspt=`/bin/cat $j/remount` $nfspt $j chkerr $? "$nfspt $j" to_umount="$j ${to_umount}" # XXX hope it is really a mount! fi # NFS remount handle_remount $j 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. # # The dir.cpio.gz form is there to make the copy process more efficient, # so if the cpio archive is present, it prevents the files from dir/ # from being copied. for i in ${templates} ; do for j in /conf/$i/* ; do subdir=${j##*/} if [ -d $j -a ! -f $j.cpio.gz ]; 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 / ; /rescue/tar -xpf $j) fi done for j in /conf/$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 $j`) fi done done # umount partitions used to fill the memory filesystems [ -n "${to_umount}" ] && umount $to_umount