#!/bin/bash

# variables
sqhs_file_tmp="/tmp/filesystem.squashfs"

# checks
if [ `id -u` != 0 ]; then
  echo "ERROR: You need be a root."
  echo "Use: sudo $(basename $0)"
  exit
fi

if [ -z "$1" ]; then
  echo "ERROR: You must pass an iso name as argument"
  exit
elif [ ! -f "$1" ]; then
  echo "ERROR: ${1} does not exist"
  exit
else
  original_iso="$1"
fi

if [ ! -d "/tmp/master" ]; then
  mkdir /tmp/master
fi

if [ ! -d "/tmp/unionfs" ]; then
  mkdir /tmp/unionfs
fi

if [ ! -d "/tmp/changes" ]; then
  mkdir /tmp/changes
else
  rm -f /tmp/changes/*
fi

if [ ! -d "/tmp/rw" ]; then
  mkdir /tmp/rw
else
  rm -f /tmp/rw/*
fi

if [ ! -d "/tmp/ro" ]; then
  mkdir /tmp/ro
fi

# mount the iso file
mount -o loop -t iso9660 $original_iso /mnt/ || ( echo "error: mount iso" && exit )

# mount the squashfs image
mount -o loop -t squashfs /mnt/casper/filesystem.squashfs /tmp/ro || ( echo "error: mount squashfs" && exit )

# mount sources from squashfs image with unionfs
mount -t unionfs -o dirs=/tmp/rw=rw:/tmp/ro=ro: unionfs /tmp/unionfs || ( echo "error: mount unionfs" && umount /tmp/unionfs && exit )

# prepare the chroot enviroment
mount --bind /proc /tmp/unionfs/proc

# enter into the sources with chroot
chroot /tmp/unionfs /bin/bash

# umount the chroot enviroment
umount /tmp/unionfs/proc

# regeneration of the squashfs image
test -f $sqhs_file_tmp && rm -f $sqhs_file_tmp
mksquashfs /tmp/unionfs $sqhs_file_tmp
 
# mount the iso file content with unionfs
mount -t unionfs -o dirs=/tmp/changes=rw:/mnt/=ro: unionfs /tmp/master || ( echo "error: mount master" && exit )

# copy the squashfs file to the right dir
cp -f $sqhs_file_tmp /tmp/master/casper/ || ( echo "error: copying $sqhs_file_tmp" && exit )

# copy the kernel and initrd files to the right dir
#cp -f /tmp/unionfs/boot/vmlinuz-2.6.20-15-generic /tmp/master/casper/vmlinuz || ( echo "error: copying vmlinuz" && exit )
#cp -f /tmp/unionfs/boot/initrd.img-2.6.20-15-generic /tmp/master/casper/initrd.gz || ( echo "error: copying initrd" && exit )

# create the new iso file
mkisofs -r -V "Live test" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o /tmp/live-test.iso /tmp/master/ || ( echo "error: mkisofs" )

# umount iso stuff
umount /tmp/master
umount /mnt/

#!/bin/bash

# variables
sqhs_file_tmp="/tmp/filesystem.squashfs"

# checks
if [ `id -u` != 0 ]; then
  echo "ERROR: You need be a root."
  echo "Use: sudo $(basename $0)"
  exit
fi

if [ -z "$1" ]; then
  echo "ERROR: You must pass an iso name as argument"
  exit
elif [ ! -f "$1" ]; then
  echo "ERROR: ${1} does not exist"
  exit
else
  original_iso="$1"
fi

if [ ! -d "/tmp/master" ]; then
  mkdir /tmp/master
fi

if [ ! -d "/tmp/unionfs" ]; then
  mkdir /tmp/unionfs
fi

if [ ! -d "/tmp/changes" ]; then
  mkdir /tmp/changes
else
  rm -f /tmp/changes/*
fi

if [ ! -d "/tmp/rw" ]; then
  mkdir /tmp/rw
else
  rm -f /tmp/rw/*
fi

if [ ! -d "/tmp/ro" ]; then
  mkdir /tmp/ro
fi

# mount the iso file
mount -o loop -t iso9660 $original_iso /mnt/ || ( echo "error: mount iso" && exit )

# mount the squashfs image
mount -o loop -t squashfs /mnt/casper/filesystem.squashfs /tmp/ro || ( echo "error: mount squashfs" && exit )

# mount sources from squashfs image with unionfs
mount -t unionfs -o dirs=/tmp/rw=rw:/tmp/ro=ro: unionfs /tmp/unionfs || ( echo "error: mount unionfs" && umount /tmp/unionfs && exit )

# prepare the chroot enviroment
mount --bind /proc /tmp/unionfs/proc

# enter into the sources with chroot
chroot /tmp/unionfs /bin/bash

# umount the chroot enviroment
umount /tmp/unionfs/proc

# regeneration of the squashfs image
test -f $sqhs_file_tmp && rm -f $sqhs_file_tmp
mksquashfs /tmp/unionfs $sqhs_file_tmp
 
# mount the iso file content with unionfs
mount -t unionfs -o dirs=/tmp/changes=rw:/mnt/=ro: unionfs /tmp/master || ( echo "error: mount master" && exit )

# copy the squashfs file to the right dir
cp -f $sqhs_file_tmp /tmp/master/casper/ || ( echo "error: copying $sqhs_file_tmp" && exit )

# copy the kernel and initrd files to the right dir
#cp -f /tmp/unionfs/boot/vmlinuz-2.6.20-15-generic /tmp/master/casper/vmlinuz || ( echo "error: copying vmlinuz" && exit )
#cp -f /tmp/unionfs/boot/initrd.img-2.6.20-15-generic /tmp/master/casper/initrd.gz || ( echo "error: copying initrd" && exit )

# create the new iso file
mkisofs -r -V "Live test" -cache-inodes -J -l -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o /tmp/live-test.iso /tmp/master/ || ( echo "error: mkisofs" )

# umount iso stuff
umount /tmp/master
umount /mnt/

This is a simple script for testing changes in a live iso created with squashfs filesystem for the compression.
It will take the iso path as a parameter and it will open it up with unionfs to let you modify its content (into a chroot enviroment) and when you get out, it will create a new iso file with the new content.

It's pretty simple and easy stuff but useful for every day testing.

Quick remastering of a Ubuntu based Live iso

ubuntu

Bash