#!/bin/bash -e

if [[ "$UID" != "0" ]] ; then
    echo 'This script can only be run as root'
    exit 1
fi

export DEV='/dev/sdc'
export USB="${DEV}1"
export CHROOT='/media/chroot'
export ARCH='i386'
export CODE_NAME='testing'
export MNT='/mnt'
export MIRROR='http://http.us.debian.org/debian/'
export KERNEL="linux-image-686"

#These are extra packages that make using the USB for 
#non-installation tasks easier.
export EXTRAS='xorg lxde-common iceweasel build-essential ntfs-3g rsync p7zip unzip unrar'

#This funtion checks that a given device or path is mounted, and if the
#parameter is, this function then unmounts it.
#param: A mount point or device file
function unmount {
    if mount | grep $1 > /dev/null ; then
        if ! umount -v -f $1 ; then
            #Try lazy unmounting as a last resort
            umount -v -l $1
        fi
    fi
}

#This function unmounts all the mount-points created in this script. It is used
#to clean-up at the end or after an error occurs. This function does not check
#"devices" it instead calls the unmount function using mount points. Hence the
#$USB device may still be mounted after a call to this function if it is
#mounted anywhere other then $MNT.
function unmount_all {
    unmount $CHROOT/proc
    unmount $CHROOT/dev/pts
    unmount $CHROOT/dev/shm
    unmount $CHROOT/dev
    unmount $CHROOT/sys
    unmount $CHROOT/boot
    unmount $MNT
}

#This function is used to cleanly exit the script. It does this by unmounting 
#all devices, displaying a given error message, and exiting with an error
#code.
#param: The error message to display.
#usage: die "This is an error"
function die {
    unmount_all
    echo
    echo "***************************************************"
    echo "$@"
    echo "***************************************************"
    echo
    exit 1
}

#We may have been left in a bad state so unmount everything
unmount_all

if [ ! -e $DEV ] ; then
    die "USB device $DEV does not exist."
fi

#Unmount the USB drive if it is mounted
if mount | grep $USB >/dev/null ; then
    echo "Unmounting device $USB"
    if ! umount -v $USB ; then
        die "Could not unmount $USB"
    fi
fi

echo "Remaking the file USB drive's partition table"
if ! ( echo -e 'o\nn\np\n1\n\n\nt\n83\na\n1\nw\n' | fdisk -c -u "$DEV" ) ; then
    die 'Could not fix the USB drives partition table'
fi

echo "Formating and tuning the USB drive"
if ! (mkfs.ext3 -L 'USB-Installer' "$USB" && tune2fs -c 0 -i 0 $USB) ; then
   die 'Could not format drive'
fi

#If the $CHROOT directory exits, destroy it so we have a clean slate.
if [ -d $CHROOT ] ; then
    echo "Clearing $CHROOT for a clean slate ..."
    if ! rm -rf "$CHROOT" ; then
        die "Could not remove the directory"
    fi
fi

#Create the $CHROOT directory
if ! mkdir -vp "$CHROOT" ; then
    die "Could not create the chroot directory at $CHROOT"
fi

if [ ! -f /usr/sbin/debootstrap ] ; then
    sudo apt-get -y install debootstrap
fi

echo 'Bootstraping in a basic system'
if ! /usr/sbin/debootstrap --arch "$ARCH" "$CODE_NAME" "$CHROOT" "$MIRROR" ; then
    die 'Failed to bootstrap'
fi

#Copy the timezone info from the system to the new USB drive
if ! cp /etc/timezone "$CHROOT/etc/timezone" ; then
    die 'Failed to update the /etc/timezone file'
fi

#Set some imporant networking configuration files
echo "Set $CHROOT/etc/hostname"
if ! echo 'usb' > $CHROOT/etc/hostname ; then
    die "Failed to update the /etc/hostname file"
fi

if ! echo '127.0.0.1 localhost usb' > $CHROOT/etc/hosts ; then
    die 'Failed to create the /etc/hosts file'
fi

if ! echo "deb $MIRROR ${CODE_NAME} main contrib non-free
deb http://security.debian.org ${CODE_NAME}/updates main contrib non-free
" > $CHROOT/etc/apt/sources.list ; then
    die 'Failed to create /etc/apt/sources.list file'
fi

if ! echo "
proc      /proc     proc    defaults          0 0
tmpfs     /tmp      tmpfs   defaults,noatime  0 0
 
#Allow useless files to be automatically deleted
tmpfs     /var/lock tmpfs   defaults,noatime  0 0
tmpfs     /var/run  tmpfs   defaults,noatime  0 0
tmpfs     /var/tmp  tmpfs   defaults,noatime  0 0
" > $CHROOT/etc/fstab ; then
    die 'Failed to create /etc/fstab file'
fi

if ! echo "
# Kernel Image management overrides
# See kernel-img.conf(5) for details
do_symlinks = yes
relative_links = yes
do_bootloader = no
do_bootfloppy = no
do_initrd = yes
link_in_boot = no" > $CHROOT/etc/kernel-img.conf ; then
    die 'Failed to create /etc/kernel-img.conf file'
fi

if ! echo "syntax on
set noai
set expandtab
set ts=2
set sw=2" > $CHROOT/root/.vimrc ; then
    die 'Failed to create /root/.vimrc file'
fi

if ! cp $CHROOT/root/.vimrc $CHROOT/etc/skel/ ; then
    die 'Copy the .vimrc file to /etc/skel'
fi


echo "Binding the needed directories under $CHROOT ..."
if [ ! -d ${CHROOT}${MNT} ] ; then
    mkdir ${CHROOT}${MNT}
fi

if ! (mount -v --bind /proc $CHROOT/proc       &&
      mount -v --bind /sys $CHROOT/sys         &&
      mount -v --bind /dev $CHROOT/dev         &&
      mount -v --bind /dev/pts $CHROOT/dev/pts &&
      mount -v --bind /dev/shm $CHROOT/dev/shm ) ; then
    die 'A mount failed!'
fi

if ! mount -v -t ext3 $USB $MNT ; then
    die "Failed to mount $USB at $MNT"
fi

if ! mkdir -v $MNT/boot $MNT/live ; then
    die "Could not create $MNT/boot and $MNT/live"
fi

if ! mount -v -o bind $MNT/boot $CHROOT/boot ; then
    die "Could not bind $MNT/boot to $CHROOT/boot"
fi

#Install the .bashrc file for the new system
cat > $CHROOT/root/.bashrc <<EOF
#!/bin/bash

#Include the default bashrc file
. /etc/skel/.bashrc
 
#Set the prompt
export PS1="\\[\\033[0;31m\\]\\u:\\w#\\[\\033[0m\\] "
 
umask 022
 
#Make file removal interactive by default
alias rm="rm -i"

if ! ifconfig eth0 2> /dev/null | grep -q 'inet addr' ; then
  sed 's/allow-hotplug/auto/' /etc/network/interfaces > /tmp/interfaces
  mv /tmp/interfaces  /etc/network/interfaces

  if ! ( /etc/init.d/networking stop && /etc/init.d/networking start ); then
    echo "Networking is not functioning!!!!"
  fi
fi
 
EOF

#This should keep any prompts from showing up
if ! echo "grub-pc grub-pc/kopt_extracted  boolean false
grub-pc grub2/kfreebsd_cmdline  string
grub-pc grub2/device_map_regenerated    note
grub-pc grub-pc/install_devices multiselect     $USB
grub-pc grub-pc/postrm_purge_boot_grub  boolean false
grub-pc grub-pc/install_devices_failed_upgrade  boolean true
grub-pc grub2/linux_cmdline     string
grub-pc grub-pc/install_devices_empty   boolean false
grub-pc grub2/kfreebsd_cmdline_default  string  quiet
grub-pc grub-pc/install_devices_failed  boolean false
grub-pc grub-pc/install_devices_disks_changed   multiselect
grub-pc grub2/linux_cmdline_default     string  quiet
grub-pc grub-pc/chainload_from_menu.lst boolean true
grub-pc grub-pc/mixed_legacy_and_grub2  boolean true
keyboard-configuration  keyboard-configuration/modelcode        string  pc105
keyboard-configuration  keyboard-configuration/unsupported_config_options       booleantrue
keyboard-configuration  keyboard-configuration/unsupported_config_layout        booleantrue
keyboard-configuration  keyboard-configuration/toggle   select  No toggling
keyboard-configuration  keyboard-configuration/compose  select  No compose key
keyboard-configuration  keyboard-configuration/layout   select
keyboard-configuration  keyboard-configuration/xkb-keymap       select  us
keyboard-configuration  keyboard-configuration/variant  select  USA
keyboard-configuration  keyboard-configuration/switch   select  No temporary switch
keyboard-configuration  keyboard-configuration/unsupported_options      boolean true
keyboard-configuration  keyboard-configuration/altgr    select  The default for the keyboard layout
keyboard-configuration  keyboard-configuration/ctrl_alt_bksp    boolean false
keyboard-configuration  keyboard-configuration/unsupported_layout       boolean true
keyboard-configuration  keyboard-configuration/variantcode      string
keyboard-configuration  keyboard-configuration/model    select  Generic 105-key (Intl) PC
keyboard-configuration  keyboard-configuration/layoutcode       string  us
keyboard-configuration  keyboard-configuration/store_defaults_in_debconf_db     booleantrue
keyboard-configuration  keyboard-configuration/optionscode      string
console-setup   console-setup/codeset47 select  . Combined - Latin; Slavic Cyrillic; Greek
console-setup   console-setup/fontface47        select  Fixed
console-setup   console-setup/fontsize-text47   select  16
console-setup   console-setup/charmap47 select  UTF-8
console-setup   console-setup/codesetcode       string  Uni2
console-setup   console-setup/store_defaults_in_debconf_db      boolean true
console-setup   console-setup/fontsize-fb47     select  16
console-setup   console-setup/fontsize  string  16
" > $CHROOT/root/conf ; then
    die "Failed to create pre-selections file."
fi

#Create a script that does installation under chroot
if ! echo "#!/bin/bash -e

ln -sf /usr/share/zoneinfo/US/Central /etc/localtime

groupadd admin
usermod -a -G 'users,plugdev,audio,cdrom,admin,disk' root
passwd -d root

#/usr/sbin/locale-gen en_US.UTF-8

debconf-set-selections /root/conf
rm /root/conf
export DEBIAN_FRONTEND=noninteractive

apt-get clean
apt-get update || apt-get update
apt-get -y dist-upgrade && apt-get -y autoremove

apt-get -y install grub2
apt-get -y install $KERNEL dhcpcd squashfs-tools  \
                   dialog mingetty vim-nox wget jfsutils \
                   parted gpm laptop-detect debootstrap less  \
                   initramfs-tools live-boot locales \
                   debconf-utils #network-manager

apt-get -y install $EXTRAS

apt-get -y clean

#Force a black listing of the old pc-speaker driver
echo blacklist snd-pcsp >> /etc/modprobe.d/blacklist.conf


echo '%admin ALL=(ALL) NOPASSWD: ALL' >> /etc/sudoers

sed 's|\([0-9]\):.*getty.*|\1:23:respawn:/sbin/mingetty --autologin root --noclear tty\1|' /etc/inittab > /tmp/inittab
mv /tmp/inittab /etc/inittab

chown root:root /root/.bashrc

" | tee $CHROOT/chroot-install > /dev/null ; then
    die "Could not create the script that manages the chroot install."
fi

if ! chmod u+x $CHROOT/chroot-install ; then
    die "Could not make the chroot install script executable."
fi

echo 'Performing chroot install ...'
if ! LANG=C chroot $CHROOT /chroot-install ; then
    die "Chroot install failed!"
fi

#udev is attached to *this* machine's network card now.
#Get rid of this rule to make udev think it is a brand new install
if ! rm /media/chroot/etc/udev/rules.d/70-persistent-net.rules ; then
    echo "WARNING: Could not fix network card udev rules"
fi

#By default the interfaces file has allow-hotplug instead of
#the auto keyword. The allow-hotplug won't allow the network
#card to start. We need the interfaces file to be modified
#before ifup is executed. So we will rewrite part of the
#networking startup script to fix the interfaces file
#just before ifup is executed.
cat $CHROOT/etc/init.d/networking | awk "
/ifup -a/ { 
    print \"\tsed 's/allow-hotplug/auto/' /etc/network/interfaces > /tmp/interfaces\" ; 
    print \"\tmv /tmp/interfaces  /etc/network/interfaces\" 
} 

{print \$0}" > /tmp/networking
mv /tmp/networking $CHROOT/etc/init.d/networking
chmod 755 $CHROOT/etc/init.d/networking

if ! echo 'live/*
proc/*
sys/*
tmp/*
boot/*
lost+found/*
media/*
mnt/*
srv/*
var/lock/*
var/log/*
var/tmp/*
var/run/*
var/lib/dhcp?/*
var/lib/urandom/*
var/cache/apt/archives/*.deb
var/lib/dpkg/*-old
var/cache/apt/archives/partial/*.deb
etc/mtab
chroot-install
' | tee $CHROOT/tmp/exclude > /dev/null ; then
    die 'Could not create the squashfs exclusion file'
fi

echo 'Discovering what files to zero out...'
if ! (find $CHROOT/usr/share/doc -type f -size +1b > /tmp/commit_zerosize   &&
      find $CHROOT/usr/share/man -type f -size +1b >> /tmp/commit_zerosize  &&
      find $CHROOT/usr/share/info -type f -size +1b >> /tmp/commit_zerosize ) ; then
    die "Could not find /usr/shar/doc files to zero out"
fi

echo 'Making the man, doc, and info files have zero size ...'
NFILES=`wc -l /tmp/commit_zerosize | awk '{ print $1 }'`
i=1
cat /tmp/commit_zerosize | while read file ; do
    echo -n -e "\tZeroing $i/$NFILES files\r"
    rm $file
    touch $file
    i=$[i + 1]
done ; echo

echo 'Unmounting runtime filesystems'
unmount $CHROOT/proc
unmount $CHROOT/dev/pts
unmount $CHROOT/dev/shm
unmount $CHROOT/dev
unmount $CHROOT/sys
mount -v --bind ${MNT} $CHROOT${MNT}

echo 'Creating the file system file.'
if ! chroot $CHROOT /usr/bin/mksquashfs / $MNT/live/filesystem.squashfs -noappend -always-use-fragments -wildcards -ef /tmp/exclude -processors 1; then
    die "Failed to squash the file system."
fi

echo "Rebinding the needed directories under $CHROOT ..."
if ! (mount -v --bind /proc $CHROOT/proc       &&
      mount -v --bind /sys $CHROOT/sys         &&
      mount -v --bind /dev $CHROOT/dev         &&
      mount -v --bind /dev/pts $CHROOT/dev/pts &&
      mount -v --bind /dev/shm $CHROOT/dev/shm ) ; then
    die 'A mount failed!'
fi

###############################################################################
#
# Install Extlinux
#
###############################################################################

if ! mkdir $MNT/extlinux; then
    echo 'Could not make extlinux directory'
fi

pushd $MNT >/dev/null
cat > $MNT/extlinux/extlinux.conf <<EOF
prompt 0
timeout 1
default Debian

label Debian
  kernel /$(echo boot/vmlinuz*)
  append initrd=/$(echo boot/initrd.img*) -- boot=live quiet splash toram=filesystem.squashfs acpi=off vga=0x305
EOF
popd > /dev/null

if ! which extlinux > /dev/null ; then
    echo 'Installing Extlinux'
    apt-get -y install extlinux
fi

if ! extlinux --install $MNT/extlinux 2> /dev/null ; then
    die 'Could not install extlinux'
fi

umount $MNT
if ! dd if=/usr/lib/syslinux/mbr.bin of=$DEV 2> /dev/null; then
    die 'Could not install mbr'
fi

echo 'Cleanly unmounting everything before finishing'
unmount_all

echo
echo 'Installation Finished Successfully !!!'
echo