#!/bin/bash

# default values
user=lily
loopfile=/home/lily/loopfile
size=200000
jaildir=/home/lily/lilymnt

# Usage information
function USAGE ()
{
    echo ""
    echo "USAGE: "
    echo "    create_lily_jail.sh [-s SIZE] [-p LILYPREFIX] [USER [LOOPFILE [MOUNTPOINT]]]"
    echo ""
    echo "Create a proper chroot jail for lilypond, using a loop device with "
    echo "the LOOPFILE of SIZE, mounted on MOUNTPOINT. Everything is created "
    echo "in the USER's home directory and set up for use by USER."
    echo ""
    echo "ARGUMENTS:"
    echo "    USER           The user for which the jail is set up ($user)"
    echo "    LOOPFILE       The loopfile for the raw data ($loopfile)"
    echo "    MOUNTPOINT     Where LOOPFILE will be mounted for use ($jaildir)"
    echo ""
    echo "OPTIONS:"
    echo "    -h             This usage information"
    echo "    -p LILYPREFIX  Where lilypond was manually installed to (empty)"
    echo "                   If not given, lilypond will not be installed." 
    echo "                   Can be given multiple times." 
    echo "    -s SIZE        size of the loopfile in bytes ($size)"
    echo ""
    echo "EXAMPLE:"
    echo "    create_lily_jail.sh -s 100000 lily /home/lily/lilyloopfile"
    echo ""
    exit $E_OPTERROR    # Exit and explain usage, if no argument(s) given.
}

lilyprefixes=()
#process options
while getopts ":p:s:h" Option
do
    case $Option in
        s    ) size=$OPTARG;;
        p    ) # Remove / from the front/tail of prefix, because we will use it also as relative dir!
               a=${OPTARG#/};
               lilyprefixes+=(${a%/});;
        h    ) USAGE
               exit 0;;
        *    ) echo ""
               echo "Unimplemented option chosen."
               USAGE
    esac
done
shift $((OPTIND-1))

if [ "$#" -ge "1" ]; then user=$1; fi
loopfile=/home/$user/loopfile
jaildir=/home/$user/lilymnt
if [ "$#" -ge "2" ]; then loopfile=$2; fi
if [ "$#" -ge "3" ]; then jaildir=$3; fi

lilyhome=$jaildir/lilyhome

echo "user=$user, loopfile=$loopfile, jaildir=$jaildir, size=$size, lilyprefix=${lilyprefixes[@]}"

# check if user exists. If not, add it.
home=`cut -d: -f1,6 /etc/passwd | grep -e "^$user:" | sed "s/^$user://"`
echo "HOME: $home"
if [ -d "$home" ]; then
  echo "User $user already exists";
else
  home=/home/$user/
  echo "Adding user $user with homedir $home";
  adduser --gecos "LilyPond Jail user" $user;
fi

# check if the loopfile is already used. If so, get the loop device and unmount
# just in case it is mounted
loop=`losetup -j $loopfile 2> /dev/null | cut -d: -f1 `
if [ -e "$loop" ]; then
  echo "Loop file already used on $loop, reusing it..."
  umount $loop 2> /dev/null
  losetup -d $loop
else
  loop=`losetup --find`
  echo "Finding next free loop device: $loop";
fi

# Create a loop file of the appropriate size. If it exists, ask for overwriting.
if [ -f $loopfile ]; then
  echo "Loopfile $loopfile already exists. Do you want to overwrite it? [y/N]"
  read answer
  if [ "$answer" != "y" ]; then
    echo "NOT overwriting the loopfile $loopfile. Exiting..."
    exit 1
  fi
fi

echo "Writing loopfile $loopfile of size $size"
dd if=/dev/zero of=$loopfile bs=1k count=$size

# Set up the proper loop devices
echo "Setting up $loop for file $loopfile, to be mounted at $jaildir"
mkdir -p $jaildir
losetup $loop $loopfile
mkfs -t ext3 $loop $size
mount -t ext3 $loop $jaildir
mkdir $lilyhome
chown $user $lilyhome

# copy all files required for lilypond
echo "Setting up all files needed to run lilypond"
cd $jaildir
mkdir -p bin usr/bin usr/share usr/lib usr/share/fonts/truetype ${lilyprefixes[@]} tmp
chmod a+w tmp


# build an array of the lilypond and guile binaries in all prefixes
lily_use_binaries=();
for i in ${lilyprefixes[@]}; do
  echo " Copying lilypond distribution from $i";
  cp -rL /$i/lilypond $i;
  lily_use_binaries+=(/$i/lilypond/usr/bin/lilypond /$i/lilypond/usr/bin/guile)
done
cp -L `which sh rm` bin
cp -L `which convert gs` usr/bin
# cp -L /usr/share/fonts/truetype/{msttcorefonts,ttf-liberation,ubuntu-font-family} usr/share/fonts/truetype
cp -L /usr/share/fonts/truetype usr/share/fonts

# Now the library copying magic
for i in ${lily_use_binaries[@]} `which sh rm gs convert`; do 
  echo "    Finding dependencies for binary $i"; 
  # ldd returns all dependencies, so extract the file name and then copy it
  # with the same directory path
  deps=`ldd $i | \
     sed 's:.*=> /\(.*/[^(]*\).*:/\1:' | \
     sed 's:\t/\(.*/.*\) (.*)$:/\1:'  | \
     sed '/.*=>.*/d'; `
  for i in $deps; do
    cp -rL --parents "$i" .
  done
done 

# The shared files for ghostscript and ImageMagick
cp -rL /usr/share/ghostscript usr/share
cp -rL /usr/lib/ImageMagick* usr/lib


# Finally, print out some information for the user how to set up sudo and fstab:
echo "
/========================================================================\ 
| Setup of the lilypond chroot jail on $jaildir finished.                
| Installed LilyPond binaries from prefixes:"
for i in ${lilyprefixes[@]}; do
  echo "\
|        $i"
done
echo "\
| 
| Please add the following line to /etc/fstab to automatically mount
| the loop device:
|        $lilyloop $jaildir    ext3 auto,loop=$loop 0       0
|
| To enable a user USER to run 'sudo lilypond -j...' for any of these
| lilypond installations, please add the following lines to /etc/sudoers:"
for i in ${lilyprefixes[@]}; do
  echo "\
|        USER   ALL=NOPASSWD: /$i/lilypond/usr/bin/lilypond -j$user,$user,$jaildir,/lilyhome *"
done
echo \
"|
\========================================================================/ 
"