etc/rc.initdiskless

   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 # $FreeBSD$
  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 typically 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 successive 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 manageable 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/remount_subdir
  77 #               If this file exists, then the behaviour of /conf/T/M/remount
  78 #               changes as follows:
  79 #                1. /conf/T/M/remount is invoked to mount the root of the
  80 #                   filesystem where the configuration data exists on a
  81 #                   temporary mountpoint.
  82 #                2. /conf/T/M/remount_subdir is then invoked to mount a
  83 #                   *subdirectory* of the filesystem mounted by
  84 #                   /conf/T/M/remount on /conf/T/M/.
  85 #
  86 # /conf/T/M/diskless_remount
  87 #               The contents of the file points to an NFS filesystem,
  88 #               possibly followed by mount_nfs options. If the server name
  89 #               is omitted, the script will prepend the root path used when
  90 #               booting. E.g. if you booted from foo.com:/path/to/root,
  91 #               an entry for /conf/base/etc/diskless_remount could be any of
  92 #                       foo.com:/path/to/root/etc
  93 #                       /etc -o ro
  94 #               Because mount_nfs understands ".." in paths, it is
  95 #               possible to mount from locations above the NFS root with
  96 #               paths such as "/../../etc".
  97 #
  98 # /conf/T/M/md_size
  99 #               The contents of the file specifies the size of the memory
 100 #               filesystem to be created, in 512 byte blocks.
 101 #               The default size is 10240 blocks (5MB). E.g. if
 102 #               /conf/base/etc/md_size contains "30000" then a 15MB MFS
 103 #               will be created. In case of multiple entries for the same
 104 #               directory M, the last one in the scanning order is used.
 105 #               NOTE: If you only need to create a memory filesystem but not
 106 #               initialize it from a template, it is preferrable to specify
 107 #               it in fstab e.g. as  "md /tmp mfs -s=30m,rw 0 0"
 108 #
 109 # /conf/T/SUBDIR.cpio.gz
 110 #               The file is cpio'd into /SUBDIR (and a memory filesystem is
 111 #               created for /SUBDIR if necessary). The presence of this file
 112 #               prevents the copy from /conf/T/SUBDIR/
 113 #
 114 # /conf/T/SUBDIR.remove
 115 #               The list of paths contained in the file are rm -rf'd
 116 #               relative to /SUBDIR.
 117 #
 118 # /conf/diskless_remount
 119 #               Similar to /conf/T/M/diskless_remount above, but allows
 120 #               all of /conf to be remounted.  This can be used to allow
 121 #               multiple roots to share the same /conf.
 122 #
 123 #
 124 # You will almost universally want to create the following files under /conf
 125 #
 126 # File                                  Content
 127 # ----------------------------          ----------------------------------
 128 # /conf/base/etc/md_size                size of /etc filesystem
 129 # /conf/base/etc/diskless_remount       "/etc"
 130 # /conf/default/etc/rc.conf             generic diskless config parameters
 131 # /conf/default/etc/fstab               generic diskless fstab e.g. like this
 132 #
 133 #       foo:/root_part                  /       nfs     ro              0 0
 134 #       foo:/usr_part                   /usr    nfs     ro              0 0
 135 #       foo:/home_part                  /home   nfs     rw              0 0
 136 #       md                              /tmp    mfs     -s=30m,rw       0 0
 137 #       md                              /var    mfs     -s=30m,rw       0 0
 138 #       proc                            /proc   procfs  rw              0 0
 139 #
 140 # plus, possibly, overrides for password files etc.
 141 #
 142 # NOTE!  /var, /tmp, and /dev will be typically created elsewhere, e.g.
 143 # as entries in the fstab as above.
 144 # Those filesystems should not be specified in /conf.
 145 #
 146 # (end of documentation, now get to the real code)
 147
 148 dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null`
 149
 150 # DEBUGGING
 151 # log something on stdout if verbose.
 152 o_verbose=0     # set to 1 or 2 if you want more debugging
 153 log() {
 154     [ ${o_verbose} -gt 0 ] && echo "*** $* ***"
 155     [ ${o_verbose} -gt 1 ] && read -p "=== Press enter to continue" foo
 156 }
 157
 158 # chkerr:
 159 #
 160 # Routine to check for error
 161 #
 162 #       checks error code and drops into shell on failure.
 163 #       if shell exits, terminates script as well as /etc/rc.
 164 #       if remount_optional exists under the mountpoint, skip this check.
 165 #
 166 chkerr() {
 167     lastitem () ( n=$(($# - 1)) ; shift $n ; echo $1 )
 168     mountpoint="$(lastitem $2)"
 169     [ -r $mountpoint/remount_optional ] && ( echo "$2 failed: ignoring due to remount_optional" ; return )
 170     case $1 in
 171     0)
 172         ;;
 173     *)
 174         echo "$2 failed: dropping into /bin/sh"
 175         /bin/sh
 176         # RESUME
 177         ;;
 178     esac
 179 }
 180
 181 # The list of filesystems to umount after the copy
 182 to_umount=""
 183
 184 handle_remount() { # $1 = mount point
 185     local nfspt mountopts b
 186     b=$1
 187     log handle_remount $1
 188     [ -d $b -a -f $b/diskless_remount ] || return
 189     read nfspt mountopts < $b/diskless_remount
 190     log "nfspt ${nfspt} mountopts ${mountopts}"
 191     # prepend the nfs root if not present
 192     [ `expr "$nfspt" : '\(.\)'` = "/" ] && nfspt="${nfsroot}${nfspt}"
 193     mount_nfs $mountopts $nfspt $b
 194     chkerr $? "mount_nfs $nfspt $b"
 195     to_umount="$b ${to_umount}"
 196 }
 197
 198 # Create a generic memory disk
 199 #
 200 mount_md() {
 201     /sbin/mdmfs -S -i 4096 -s $1 -M md $2
 202 }
 203
 204 # Create the memory filesystem if it has not already been created
 205 #
 206 create_md() {
 207         [ "x`eval echo \\$md_created_$1`" = "x" ] || return # only once
 208         if [ "x`eval echo \\$md_size_$1`" = "x" ]; then
 209             md_size=10240
 210         else
 211             md_size=`eval echo \\$md_size_$1`
 212         fi
 213         log create_md $1 with size $md_size
 214         mount_md $md_size /$1
 215         /bin/chmod 755 /$1
 216         eval md_created_$1=created
 217 }
 218
 219 # DEBUGGING
 220 #
 221 # set -v
 222
 223 # Figure out our interface and IP.
 224 #
 225 bootp_ifc=""
 226 bootp_ipa=""
 227 bootp_ipbca=""
 228 class=""
 229 if [ ${dlv:=0} -ne 0 ] ; then
 230         iflist=`ifconfig -l`
 231         for i in ${iflist} ; do
 232             set -- `ifconfig ${i}`
 233             while [ $# -ge 1 ] ; do
 234                 if [ "${bootp_ifc}" = "" -a "$1" = "inet" ] ; then
 235                     bootp_ifc=${i} ; bootp_ipa=${2} ; shift
 236                 fi
 237                 if [ "${bootp_ipbca}" = "" -a "$1" = "broadcast" ] ; then
 238                     bootp_ipbca=$2; shift
 239                 fi
 240                 shift
 241             done
 242             if [ "${bootp_ifc}" != "" ] ; then
 243                 break
 244             fi
 245         done
 246         # Get the values passed with the T134 bootp cookie.
 247         class="`/sbin/sysctl -qn kern.bootp_cookie`"
 248
 249         echo "Interface ${bootp_ifc} IP-Address ${bootp_ipa} Broadcast ${bootp_ipbca} ${class}"
 250 fi
 251
 252 log Figure out our NFS root path
 253 #
 254 set -- `mount -t nfs`
 255 while [ $# -ge 1 ] ; do
 256     if [ "$2" = "on" -a "$3" = "/" ]; then
 257         nfsroot="$1"
 258         break
 259     fi
 260     shift
 261 done
 262
 263 # The list of directories with template files
 264 templates="base default"
 265 if [ -n "${bootp_ipbca}" ]; then
 266         templates="${templates} ${bootp_ipbca} bcast/${bootp_ipbca}"
 267 fi
 268 if [ -n "${class}" ]; then
 269         templates="${templates} ${class}"
 270 fi
 271 if [ -n "${bootp_ipa}" ]; then
 272         templates="${templates} ${bootp_ipa} ip/${bootp_ipa}"
 273 fi
 274
 275 # If /conf/diskless_remount exists, remount all of /conf.
 276 handle_remount /conf
 277
 278 # Resolve templates in /conf/base, /conf/default, /conf/${bootp_ipbca},
 279 # and /conf/${bootp_ipa}.  For each subdirectory found within these
 280 # directories:
 281 #
 282 # - calculate memory filesystem sizes.  If the subdirectory (prior to
 283 #   NFS remounting) contains the file 'md_size', the contents specified
 284 #   in 512 byte sectors will be used to size the memory filesystem.  Otherwise
 285 #   8192 sectors (4MB) is used.
 286 #
 287 # - handle NFS remounts.  If the subdirectory contains the file
 288 #   diskless_remount, the contents of the file is NFS mounted over
 289 #   the directory.  For example /conf/base/etc/diskless_remount
 290 #   might contain 'myserver:/etc'.  NFS remounts allow you to avoid
 291 #   having to dup your system directories in /conf.  Your server must
 292 #   be sure to export those filesystems -alldirs, however.
 293 #   If the diskless_remount file contains a string beginning with a
 294 #   '/' it is assumed that the local nfsroot should be prepended to
 295 #   it before attemping to the remount.  This allows the root to be
 296 #   relocated without needing to change the remount files.
 297 #
 298 log "templates are ${templates}"
 299 for i in ${templates} ; do
 300     for j in /conf/$i/* ; do
 301         [ -d $j ] || continue
 302
 303         # memory filesystem size specification
 304         subdir=${j##*/}
 305         [ -f $j/md_size ] && eval md_size_$subdir=`cat $j/md_size`
 306
 307         # remount. Beware, the command is in the file itself!
 308         if [ -f $j/remount ]; then
 309             if [ -f $j/remount_subdir ]; then
 310                 k="/conf.tmp/$i/$subdir"
 311                 [ -d $k ] || continue
 312
 313                 # Mount the filesystem root where the config data is
 314                 # on the temporary mount point.
 315                 nfspt=`/bin/cat $j/remount`
 316                 $nfspt $k
 317                 chkerr $? "$nfspt $k"
 318
 319                 # Now use a nullfs mount to get the data where we
 320                 # really want to see it.
 321                 remount_subdir=`/bin/cat $j/remount_subdir`
 322                 remount_subdir_cmd="mount -t nullfs $k/$remount_subdir"
 323
 324                 $remount_subdir_cmd $j
 325                 chkerr $? "$remount_subdir_cmd $j"
 326
 327                 # XXX check order -- we must force $k to be unmounted
 328                 # after j, as j depends on k.
 329                 to_umount="$j $k ${to_umount}"
 330             else
 331                 nfspt=`/bin/cat $j/remount`
 332                 $nfspt $j
 333                 chkerr $? "$nfspt $j"
 334                 to_umount="$j ${to_umount}" # XXX hope it is really a mount!
 335             fi
 336         fi
 337
 338         # NFS remount
 339         handle_remount $j
 340     done
 341 done
 342
 343 # - Create all required MFS filesystems and populate them from
 344 #   our templates.  Support both a direct template and a dir.cpio.gz
 345 #   archive.  Support dir.remove files containing a list of relative
 346 #   paths to remove.
 347 #
 348 # The dir.cpio.gz form is there to make the copy process more efficient,
 349 # so if the cpio archive is present, it prevents the files from dir/
 350 # from being copied.
 351
 352 for i in ${templates} ; do
 353     for j in /conf/$i/* ; do
 354         subdir=${j##*/}
 355         if [ -d $j -a ! -f $j.cpio.gz  ]; then
 356             create_md $subdir
 357             cp -Rp $j/ /$subdir
 358         fi
 359     done
 360     for j in /conf/$i/*.cpio.gz ; do
 361         subdir=${j%*.cpio.gz}
 362         subdir=${subdir##*/}
 363         if [ -f $j ]; then
 364             create_md $subdir
 365             echo "Loading /$subdir from cpio archive $j"
 366             (cd / ; /rescue/tar -xpf $j)
 367         fi
 368     done
 369     for j in /conf/$i/*.remove ; do
 370         subdir=${j%*.remove}
 371         subdir=${subdir##*/}
 372         if [ -f $j ]; then
 373             # doubly sure it is a memory disk before rm -rf'ing
 374             create_md $subdir
 375             (cd /$subdir; rm -rf `/bin/cat $j`)
 376         fi
 377     done
 378 done
 379
 380 # umount partitions used to fill the memory filesystems
 381 [ -n "${to_umount}" ] && umount $to_umount