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   -p PROGRAM     Arbitrary program/script that is run inside of the livecd root
  38             filesystem.  This script is not run in a chroot environment so
  39             it can access the host filesystem.  The program should be executable
  40             If program is omitted the script will pause and allow the user in
  41             another terminal to edit the filesystem manually.  After enter is
  42             pushed the script will re-package up the ISO.
  43   -h             display this help and exit
  44
  45   Example Script:
  46     #!/bin/sh
  47     touch etc/sysconfig/foo
  48
  49   This will create a file /etc/sysconfig/foo in the livecd filesystem.
  50 EOF
  51 }
  52
  53 # FIXME: instead of requiring a PROGRAM, allow arbitrary shell code,
  54 # so we can invoke $0 -p 'touch etc/sysconfig/foo' ...
  55 # This means that if you *do* have a program in the current directory
  56 # running "$0 -p ./my-script" won't work, since it'll be run with
  57 # a different working dir.  However, *this* will:
  58 # $0 -p "$PWD/my-script"
  59
  60 # exit after any error:
  61 set -e
  62
  63 err=0 help=0
  64 while getopts :b:i:p:h c; do
  65     case $c in
  66         i) CD=$OPTARG;;
  67         b) PARAMS=$OPTARG;;
  68         p) PROG=$OPTARG;;
  69         h) help=1;;
  70         '?') err=1; warn "invalid option: \`-$OPTARG'";;
  71         :) err=1; warn "missing argument to \`-$OPTARG' option";;
  72         *) err=1; warn "internal error: \`-$OPTARG' not handled";;
  73     esac
  74 done
  75 test $err = 1 && { try_h; exit 1; }
  76 test $help = 1 && { usage; exit 0; }
  77
  78 # first, check to see we are root
  79 if [ $( id -u ) -ne 0 ]; then
  80     die "Must run as root"
  81 fi
  82
  83 # FIXME: don't use which: with bash, it's a separate program
  84 # FIXME: When failing due to a missing required program, tell the user why.
  85 which mkisofs mksquashfs sed > /dev/null 2>&1
  86
  87 WDIR=`mktemp -d $PWD/livecd.XXXXXXXXXX`
  88 # FIXME: fail if $WDIR contains white space or shell meta-characters
  89 # FIXME: do the same for $CD.
  90
  91 ISO="${CD##*/}"
  92 ISO="${ISO%.iso}-custom.iso"
  93
  94 function addExit() {
  95     EXIT="$@ ; $EXIT"
  96     trap "$EXIT" EXIT HUP TERM INT QUIT
  97 }
  98
  99 function mnt() {
 100     local margs="$1" ; shift
 101     local mp="$WDIR/$1"
 102     for D in "$@" ; do
 103         mkdir -v -p "$WDIR/$D"
 104     done
 105     mount -v $margs "$mp"
 106     addExit "df | grep $mp > /dev/null 2>&1 && umount -v $mp"
 107 }
 108
 109 addExit "rm -rf $WDIR"
 110
 111 eval "$(/lib/udev/vol_id $CD)"
 112 LABEL=$ID_FS_LABEL
 113
 114 # mount the CD image
 115 mnt "-t auto $CD -o loop,ro" cd
 116
 117 # mount compressed filesystem
 118 mnt "-t squashfs $WDIR/cd/LiveOS/squashfs.img -o ro,loop" sq
 119
 120 # create writable copy of the new filesystem for the CD
 121 cp -a $WDIR/cd $WDIR/cd-w
 122
 123 # create writable copy of the filesystem for the new compressed squashfs filesystem
 124 cp -a $WDIR/sq $WDIR/sq-w
 125
 126 # mount ext3 filesystem
 127 mnt "-t auto $WDIR/sq-w/LiveOS/ext3fs.img -o rw,loop" ex
 128
 129 echo ">>> Updating CD content"
 130 if [ -n "$PROG" ]; then
 131     cp -av $PROG $WDIR/ex
 132     pushd $WDIR/ex
 133     set +e
 134     ./$(basename $PROG)
 135     set -e
 136     popd
 137     rm -f $WDIR/ex/$PROG
 138 else
 139     echo "***"
 140     echo "*** Pausing to allow manual changes.  Press any key to continue."
 141     echo "***"
 142     read
 143 fi
 144 echo ">>> Unmounting ext3fs"
 145 umount $WDIR/ex
 146
 147 echo ">>> Compressing filesystem"
 148 mksquashfs $WDIR/sq-w/ $WDIR/cd-w/LiveOS/squashfs.img -noappend
 149
 150 echo ">>> Recomputing MD5 sums"
 151 ( cd $WDIR/cd-w && find . -type f -not -name md5sum.txt -not -path '*/isolinux/*' -print0 | xargs -0 -- md5sum > md5sum.txt )
 152
 153 if [ -n "$PARAMS" ]; then
 154     # FIXME: make the script fail -- or maybe try to
 155     # find a usable sed delimiter if $PARAMS contains a slash
 156     echo ">>> Appending boot parameters"
 157     sed -i 's/^  append .*$/& '"$PARAMS/" "$WDIR/cd-w/isolinux/isolinux.cfg"
 158 fi
 159
 160 echo ">>> Creating ISO image $ISO"
 161 mkisofs \
 162     -V "$LABEL" \
 163     -r -cache-inodes -J -l \
 164     -b isolinux/isolinux.bin \
 165     -c isolinux/boot.cat \
 166     -no-emul-boot -boot-load-size 4 -boot-info-table \
 167     -o "$ISO" \
 168     $WDIR/cd-w
 169
 170 # The trap ... callbacks will unmount everything.
 171 set +e