edit-livecd

   1 #!/bin/bash
   2 #
   3 # Edit a livecd to insert files
   4 # Copyright 2008 Red Hat, Inc.
   5 # Written by Perry Myers <pmyers@redhat.com>
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; version 2 of the License.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU Library General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the Free Software
  18 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19 #!/bin/bash
  20
  21 PATH=$PATH:/sbin:/usr/sbin
  22
  23 ME=$(basename "$0")
  24 warn() { printf '%s: %s\n' "$ME" "$*" >&2; }
  25 try_h() { printf "Try \`$ME -h' for more information.\n" >&2; }
  26 die() { warn "$@"; try_h; exit 1; }
  27
  28 NODEIMG_DEFAULT=/usr/share/ovirt-node-image/ovirt-node-image.iso
  29 CD=$NODEIMG_DEFAULT
  30
  31 usage() {
  32     case $# in 1) warn "$1"; try_h; exit 1;; esac
  33     cat <<EOF
  34 Usage: $ME -i LiveCD.iso [-b bootparams] [-p program]
  35   -b BOOTPARAMS  optional parameters appended to the kernel command line
  36   -i LIVECD.iso  LiveCD ISO to edit (default: $NODEIMG_DEFAULT)
  37   -o OUTPUT.iso  specify the output file (required)
  38   -p CODE        Arbitrary CODE that is eval'd while 'cd'd into the root of
  39                    the livecd root filesystem.  Note; the code is not run in
  40                    a chroot environment, so it can access the host filesystem.
  41                    If this option is omitted, this program pauses and allows
  42                    the user (in another terminal) to modify the filesystem
  43                    manually.  Type <enter> when done, and the script
  44                    re-packages the ISO.
  45   -h             display this help and exit
  46
  47 EXAMPLES
  48
  49   Example Script:
  50     #!/bin/sh
  51     touch etc/sysconfig/foo
  52   Save as foo and make executable:
  53     chmod a+x foo
  54   Run this to create a file /etc/sysconfig/foo in the livecd filesystem
  55   (note the use of "\$PWD/foo", not "./foo", since it will be run from a
  56    different directory):
  57
  58     $ME -i input.iso -o /tmp/result.iso -p "\$PWD/foo"
  59
  60   or, equivalently, but without a separate script:
  61
  62     $ME -i input.iso -o /tmp/result.iso -p 'touch etc/sysconfig/foo'
  63
  64 EOF
  65 }
  66
  67 # exit after any error:
  68 set -e
  69
  70 CODE=
  71 OUTPUT_FILE=
  72
  73 err=0 help=0
  74 while getopts :b:hi:o:p: c; do
  75     case $c in
  76         i) CD=$OPTARG;;
  77         b) PARAMS=$OPTARG;;
  78         o) OUTPUT_FILE=$OPTARG;;
  79         p) CODE=$OPTARG;;
  80         h) help=1;;
  81         '?') err=1; warn "invalid option: \`-$OPTARG'";;
  82         :) err=1; warn "missing argument to \`-$OPTARG' option";;
  83         *) err=1; warn "internal error: \`-$OPTARG' not handled";;
  84     esac
  85 done
  86 test $err = 1 && { try_h; exit 1; }
  87 test $help = 1 && { usage; exit 0; }
  88
  89 # Require "-o OUTPUT_FILE"
  90 test -z "$OUTPUT_FILE" \
  91   && { warn "no output file specified; use -o FILE.iso"; try_h; exit 1; }
  92
  93 # Fail if there are any extra command-line arguments.
  94 if test $OPTIND -le $#; then
  95   bad_arg=$(eval "echo \$$OPTIND")
  96   warn "extra argument '$bad_arg'"; try_h; exit 1
  97 fi
  98
  99 # first, check to see we are root
 100 if [ $( id -u ) -ne 0 ]; then
 101     die "Must run as root"
 102 fi
 103
 104 # Check for some prerequisites.
 105 # "type" prints "PROG not found" if it's not in $PATH.
 106 type mkisofs
 107 type mksquashfs
 108 type sed
 109 type implantisomd5
 110
 111 sane_name()
 112 {
 113   case $1 in
 114     *[^a-zA-Z0-9._,+:/@%=-]*) false;;
 115     *) true;;
 116   esac
 117 }
 118
 119 # Fail if names we'll use contain white space or shell meta-characters
 120 sane_name "$PWD" || die "invalid working directory name: $PWD"
 121 sane_name "$CD" || die "invalid ISO name: $CD"
 122
 123 WDIR=`mktemp -d $PWD/livecd.XXXXXXXXXX`
 124
 125 addExit() {
 126     EXIT="$@ ; $EXIT"
 127     trap "$EXIT" EXIT HUP TERM INT QUIT
 128 }
 129
 130 mnt() {
 131     local margs="$1" ; shift
 132     local mp="$WDIR/$1"
 133     for D in "$@" ; do
 134         mkdir -v -p "$WDIR/$D"
 135     done
 136     eval mount -v $margs "$mp"
 137     addExit "df | grep $mp > /dev/null 2>&1 && umount -v $mp"
 138 }
 139
 140 addExit "rm -rf $WDIR"
 141
 142 ID_FS_LABEL= # initialize, in case vol_id fails
 143 eval "$(/lib/udev/vol_id $CD)"
 144 LABEL=$ID_FS_LABEL
 145
 146 # mount the CD image
 147 mnt "-t iso9660 $CD -o loop,ro" cd
 148
 149 # mount compressed filesystem
 150 mnt "-t squashfs $WDIR/cd/LiveOS/squashfs.img -o ro,loop" sq
 151
 152 # create writable copy of the new filesystem for the CD
 153 cp -pr $WDIR/cd $WDIR/cd-w
 154
 155 # create writable copy of the filesystem for the new compressed
 156 # squashfs filesystem
 157 cp -pr $WDIR/sq $WDIR/sq-w
 158
 159 # mount root filesystem
 160 mnt "-t ext2 $WDIR/sq-w/LiveOS/ext3fs.img -o rw,loop" ex
 161
 162 echo ">>> Updating CD content"
 163 if [ -n "$CODE" ]; then
 164     (
 165       cd $WDIR/ex
 166       set +e
 167       eval "$CODE"
 168       set -e
 169     )
 170 else
 171     echo "***"
 172     echo "*** Pausing to allow manual changes.  Press any key to continue."
 173     echo "***"
 174     read
 175 fi
 176
 177 # Try to unmount.  But this is likely to fail, so let the user retry,
 178 # e.g., if he forgot to "cd" out of $WDIR/ex.
 179 while :; do
 180   echo ">>> Unmounting ext3fs"
 181   umount $WDIR/ex && break
 182   echo ">>> Unmounting the working file system copy failed"
 183   echo "***"
 184   echo "*** Did you forget to 'cd' out of $WDIR/ex?"
 185   echo "***"
 186   echo "*** Press any key to repeat the attempt."
 187   echo "***"
 188   read
 189 done
 190
 191 echo ">>> Compressing filesystem"
 192 mksquashfs $WDIR/sq-w/ $WDIR/cd-w/LiveOS/squashfs.img -noappend
 193
 194 echo ">>> Recomputing MD5 sums"
 195 ( cd $WDIR/cd-w && find . -type f -not -name md5sum.txt \
 196     -not -path '*/isolinux/*' -print0 | xargs -0 -- md5sum > md5sum.txt )
 197
 198 if [ -n "$PARAMS" ]; then
 199     case $PARAMS in
 200       *@*) warn "PARAMS contains the @ sed delimiter, be sure it's escaped";;
 201     esac
 202     echo ">>> Appending boot parameters"
 203     sed -i 's@^  append .*$@& '"$PARAMS@" "$WDIR/cd-w/isolinux/isolinux.cfg"
 204 fi
 205
 206 echo ">>> Creating ISO image $ISO"
 207 mkisofs \
 208     -V "$LABEL" \
 209     -r -cache-inodes -J -l \
 210     -b isolinux/isolinux.bin \
 211     -c isolinux/boot.cat \
 212     -no-emul-boot -boot-load-size 4 -boot-info-table \
 213     -o "$OUTPUT_FILE" \
 214     $WDIR/cd-w
 215
 216 echo ">>> Implanting ISO MD5 Sum"
 217 implantisomd5 --force "$OUTPUT_FILE"
 218
 219 # The trap ... callbacks will unmount everything.
 220 set +e