#!/bin/bash
#
###########################################################################
#
# Description:
#      Sets LABEL on MSDOS partition
#
# Usage:
#      sudo $0 PARTITION LABEL
#
# Example:
#      sudo $0 /dev/hda9 MY_LABEL
#
# IN:  PARTITION LABEL
# OUT: LABEL set as label on partition PARTITION
#
# RC:
#      1 - Wrong number of parameters
#      2 - You forgot sudo.
#      3 - Partition $1 is not mounted.
#      4 - Package mtools is not installed.
#      5 - Could not copy /etc/mtools.conf to ~/.mtoolsrc.
#      6 - Could not write to ~/.mtoolsrc.
#      7 - Could not do    mcd x:
#      8 - Could not set the new label for ${1}.
#      9 - You don´t want to set label $2 for ${1}, so I´ll exit now.
#
###########################################################################

#set -x

#########################
# functions - start
#########################

function usage () {
        echo -e "\nUsage:   sudo $0 PARTITION LABEL"
        echo -e "Example: sudo $0 /dev/hda9 MY_LABEL\n"
}

function verify_uid () {
        if [ "${UID}X" != "0X" ]
        then
           echo -e "\nYou forgot sudo."
           usage
           exit 2
        fi
}

function verify_partition () {
# It is not necessary to verify the partition type, because
# mlabel can set label only on MSDOS partitions.
# But the partition has to be mounted!
        MOUNTED=$(grep $1 /etc/mtab | wc -l | tr -d ' ')
        if [ "${MOUNTED}X" != "1X" ]
        then
           echo -e "\nPartition $1 is not mounted."
           echo -e "You should mount this partition before you run this script.\n"
           exit 3
        fi
}

function verify_mtools () {
        MTOOLS=$(which mtools)
        if [ "${MTOOLS}X" = "X" ]
        then
           echo -e "\nPackage mtools is not installed."
           echo -e "You should run \"sudo apt-get install mtools\" or \"sudo aptitude install mtools\"!\n"
           exit 4
        fi
}

function save_mtoolsrc (){
# save a copy of your own ~/.mtoolsrc
        if [ -f  ~/.mtoolsrc ]
        then
           cp ~/.mtoolsrc ~/.mtoolsrc.sav
           echo -e "\n~/.mtoolsrc saved to ~/.mtoolsrc.sav"
        fi
}

function recover_mtoolsrc (){
# recover your own ~/.mtoolsrc
        if [ -f  ~/.mtoolsrc.sav ]
        then
           mv ~/.mtoolsrc.sav ~/.mtoolsrc

           # files owned by root in user´s home directory
           # it´s not nice, so reset the ownership
           chown ${SUDO_USER} ~/.mtoolsrc ~/.mcwd

           echo -e "\n~/.mtoolsrc recovered"
        fi

}


function copy_mtools.conf_to_mtoolsrc (){
# if copy does not work, mtools does not seem installed
        cp /etc/mtools.conf ~/.mtoolsrc
        if [ $? -ne 0 ]
        then
           recover_mtoolsrc
           echo -e "\nCould not copy /etc/mtools.conf to ~/.mtoolsrc.\n"
           exit 5
        fi
}


function rename_temp_mtoolsrc_and_recover_mtoolsrc (){
# copy your temporary ~/.mtoolsrc to ~/.mtoolsrc.error
        RECOVERED=0

        if [ -f  ~/.mtoolsrc ]
        then
           mv ~/.mtoolsrc ~/.mtoolsrc.error
           RECOVERED=1
        fi

        recover_mtoolsrc

        if [ "${RECOVERED}X" = "1X" ]
        then
           echo -e "\nThere is a file ~/.mtoolsrc.error"
           echo -e "~/.mtoolsrc.error was written by me."
           echo -e "Please check this file to figure out what happened.\n"
           exit $1
        fi
}


function write_new_mtoolsrc (){
# there is a copy of your original ~/.mtoolsrc
# we are going to recover this file
# we have to be sure, that there are no other settings in this file
# so we overwrite this file temporarily and recover it thereafter
        echo "drive x: file=\"${1}\"" > ~/.mtoolsrc
           if [ $? -ne 0 ]
           then
              echo -e "\nCould not write to ~/.mtoolsrc."
              rename_temp_mtoolsrc_and_recover_mtoolsrc 6
           fi
}


function set_label_on_partition () {
        # does the new ~/.mtoolsrc work?
        mcd x:
        if [ $? -ne 0 ]
        then
           echo -e "\nCould not do    mcd x:"
           echo "Check STDOUT and ~/.mtoolsrc*"
           rename_temp_mtoolsrc_and_recover_mtoolsrc 7
        fi

        # Are you sure you want to change the lable?
        echo -e "\nCurrent label for ${1}: $(mlabel -s x:)"
        read -p "Do you really want to set $2 as label for ${1}? (y/n):"

        case "$REPLY" in
        y|yes|Y|Yes|YES|j|ja|J|Ja|JA)
           # try to set the new label
           mlabel x:$2
           RC=$?
           if [ $? -eq 0 ]
           then
              echo -e "\nNew label on ${1}: $(mlabel -s x:)"
              # everything is OK, so we should only remove the temporary ~/.mtoolsrc and recover the original ~/.mtoolsrc
              recover_mtoolsrc
           else
              echo -e "\nCould not set the new label for ${1}."
              # something went wrong, so we should save the temporary ~/.mtoolsrc and recover the original ~/.mtoolsrc
              rename_temp_mtoolsrc_and_recover_mtoolsrc 8
           fi
           ;;
        *)
           echo -e "\nYou don´t want to set label $2 for ${1}, so I´ll exit now."
           recover_mtoolsrc
           echo ""
           exit 9
           ;;
        esac
}
#########################
# functions - start
#########################




#########################
# main - start
#########################

if [ $# -ne 2 ]
then
   echo -e "\nWrong number of parameters."
   usage
   exit 1
fi

verify_uid

verify_partition $1

verify_mtools

save_mtoolsrc

copy_mtools.conf_to_mtoolsrc

write_new_mtoolsrc $1

set_label_on_partition $1 $2

exit 0

#########################
# main - end
#########################