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
 110 sane_name()
 111 {
 112   case $1 in
 113     *[^a-zA-Z0-9._,+:/@%=-]*) false;;
 114     *) true;;
 115   esac
 116 }
 117
 118 # Fail if names we'll use contain white space or shell meta-characters
 119 sane_name "$PWD" || die "invalid working directory name: $PWD"
 120 sane_name "$CD" || die "invalid ISO name: $CD"
 121
 122 WDIR=`mktemp -d $PWD/livecd.XXXXXXXXXX`
 123
 124 addExit() {
 125     EXIT="$@ ; $EXIT"
 126     trap "$EXIT" EXIT HUP TERM INT QUIT
 127 }
 128
 129 mnt() {
 130     local margs="$1" ; shift
 131     local mp="$WDIR/$1"
 132     for D in "$@" ; do
 133         mkdir -v -p "$WDIR/$D"
 134     done
 135     eval mount -v $margs "$mp"
 136     addExit "df | grep $mp > /dev/null 2>&1 && umount -v $mp"
 137 }
 138
 139 addExit "rm -rf $WDIR"
 140
 141 ID_FS_LABEL= # initialize, in case vol_id fails
 142 eval "$(/lib/udev/vol_id $CD)"
 143 LABEL=$ID_FS_LABEL
 144
 145 # mount the CD image
 146 mnt "-t auto $CD -o loop,ro" cd
 147
 148 # mount compressed filesystem
 149 mnt "-t squashfs $WDIR/cd/LiveOS/squashfs.img -o ro,loop" sq
 150
 151 # create writable copy of the new filesystem for the CD
 152 cp -a $WDIR/cd $WDIR/cd-w
 153
 154 # create writable copy of the filesystem for the new compressed
 155 # squashfs filesystem
 156 cp -a $WDIR/sq $WDIR/sq-w
 157
 158 # mount ext3 filesystem
 159 mnt "-t auto $WDIR/sq-w/LiveOS/ext3fs.img -o rw,loop" ex
 160
 161 echo ">>> Updating CD content"
 162 if [ -n "$CODE" ]; then
 163     (
 164       cd $WDIR/ex
 165       set +e
 166       eval "$CODE"
 167       set -e
 168     )
 169 else
 170     echo "***"
 171     echo "*** Pausing to allow manual changes.  Press any key to continue."
 172     echo "***"
 173     read
 174 fi
 175
 176 # Try to unmount.  But this is likely to fail, so let the user retry,
 177 # e.g., if he forgot to "cd" out of $WDIR/ex.
 178 while :; do
 179   echo ">>> Unmounting ext3fs"
 180   umount $WDIR/ex && break
 181   echo ">>> Unmounting the working file system copy failed"
 182   echo "***"
 183   echo "*** Did you forget to 'cd' out of $WDIR/ex?"
 184   echo "***"
 185   echo "*** Press any key to repeat the attempt."
 186   echo "***"
 187   read
 188 done
 189
 190 echo ">>> Compressing filesystem"
 191 mksquashfs $WDIR/sq-w/ $WDIR/cd-w/LiveOS/squashfs.img -noappend
 192
 193 echo ">>> Recomputing MD5 sums"
 194 ( cd $WDIR/cd-w && find . -type f -not -name md5sum.txt \
 195     -not -path '*/isolinux/*' -print0 | xargs -0 -- md5sum > md5sum.txt )
 196
 197 if [ -n "$PARAMS" ]; then
 198     case $PARAMS in
 199       *@*) warn "PARAMS contains the @ sed delimiter, be sure it's escaped";;
 200     esac
 201     echo ">>> Appending boot parameters"
 202     sed -i 's@^  append .*$@& '"$PARAMS@" "$WDIR/cd-w/isolinux/isolinux.cfg"
 203 fi
 204
 205 echo ">>> Creating ISO image $ISO"
 206 mkisofs \
 207     -V "$LABEL" \
 208     -r -cache-inodes -J -l \
 209     -b isolinux/isolinux.bin \
 210     -c isolinux/boot.cat \
 211     -no-emul-boot -boot-load-size 4 -boot-info-table \
 212     -o "$OUTPUT_FILE" \
 213     $WDIR/cd-w
 214
 215 # The trap ... callbacks will unmount everything.
 216 set +e