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 usage() {
  29     case $# in 1) warn "$1"; try_h; exit 1;; esac
  30     cat <<EOF
  31 Usage: $ME livecd.iso program
  32   livecd.iso - LiveCD ISO to edit
  33   program - Arbitrary program/script that is run inside of the livecd root
  34             filesystem.  This script is not run in a chroot environment so
  35             it can access the host filesystem.  The program should be executable
  36             If program is omitted the script will pause and allow the user in
  37             another terminal to edit the filesystem manually.  After enter is
  38             pushed the script will re-package up the ISO.
  39
  40   Example Script:
  41     #!/bin/sh
  42     touch etc/sysconfig/foo
  43
  44   This will create a file /etc/sysconfig/foo in the livecd filesystem.
  45 EOF
  46 }
  47
  48 # exit after any error:
  49 set -e
  50
  51 test $# -lt 1 && { usage; exit 1; }
  52
  53 # first, check to see we are root
  54 if [ $( id -u ) -ne 0 ]; then
  55     die "Must run as root"
  56 fi
  57
  58 CD=$1
  59 PROG=$2
  60
  61 which mkisofs mksquashfs sed > /dev/null 2>&1
  62
  63 WDIR=`mktemp -d $PWD/livecd.XXXXXXXXXX`
  64 ISO="${CD##*/}"
  65 ISO="${ISO%.iso}-custom.iso"
  66
  67 function addExit() {
  68     EXIT="$@ ; $EXIT"
  69     trap "$EXIT" EXIT HUP TERM INT QUIT
  70 }
  71
  72 function mnt() {
  73     local margs="$1" ; shift
  74     local mp="$WDIR/$1"
  75     for D in "$@" ; do
  76         mkdir -v -p "$WDIR/$D"
  77     done
  78     mount -v $margs "$mp"
  79     addExit "df | grep $mp > /dev/null 2>&1 && umount -v $mp"
  80 }
  81
  82 addExit "rm -Rf $WDIR"
  83
  84 LABEL=$(isoinfo -d -i $CD | awk -F ": " '/Volume id:/ {print $2}')
  85
  86 # mount the CD image
  87 mnt "-t auto $CD -o loop,ro" cd
  88
  89 # mount compressed filesystem
  90 mnt "-t squashfs $WDIR/cd/LiveOS/squashfs.img -o ro,loop" sq
  91
  92 # create writable copy of the new filesystem for the CD
  93 cp -a $WDIR/cd $WDIR/cd-w
  94
  95 # create writable copy of the filesystem for the new compressed squashfs filesystem
  96 cp -a $WDIR/sq $WDIR/sq-w
  97
  98 # mount ext3 filesystem
  99 mnt "-t auto $WDIR/sq-w/LiveOS/ext3fs.img -o rw,loop" ex
 100
 101 echo ">>> Updating CD content"
 102 if [ -n "$PROG" ]; then
 103     cp -av $PROG $WDIR/ex
 104     pushd $WDIR/ex
 105     set +e
 106     ./$(basename $PROG)
 107     set -e
 108     popd
 109     rm -f $WDIR/ex/$PROG
 110 else
 111     echo "***"
 112     echo "*** Pausing to allow manual changes.  Press any key to continue."
 113     echo "***"
 114     read
 115 fi
 116 echo ">>> Unmounting ext3fs"
 117 umount $WDIR/ex
 118
 119 echo ">>> Compressing filesystem"
 120 mksquashfs $WDIR/sq-w/ $WDIR/cd-w/LiveOS/squashfs.img -noappend
 121
 122 echo ">>> Recomputing MD5 sums"
 123 ( cd $WDIR/cd-w && find . -type f -not -name md5sum.txt -not -path '*/isolinux/*' -print0 | xargs -0 -- md5sum > md5sum.txt )
 124
 125 echo ">>> Creating ISO image $ISO"
 126 mkisofs \
 127     -V "$LABEL" \
 128     -r -cache-inodes -J -l \
 129     -b isolinux/isolinux.bin \
 130     -c isolinux/boot.cat \
 131     -no-emul-boot -boot-load-size 4 -boot-info-table \
 132     -o "$ISO" \
 133     $WDIR/cd-w
 134
 135 # The trap ... callbacks will unmount everything.
 136 set +e
 137