#!/bin/sh
# This script will detect the last JFS or EXT3 partition of an SD card image
# provided by Technologic Systems and expand it to the end of the disk,
# leaving a small amount of padding.  It depends on tools such as sfdisk,
# which is part of core utilities of Linux, as well as and jfsutils if working
# with JFS filesystem.
# 
# In order to use the script, you will need to insert the SD card into the USB
# SD card reader and then use the 'fdisk -l' command to find the device node.
# The device node is typically enumerated as /dev/sdX, where X is what Linux
# decided.  Example usage is:  './grow_sd /dev/sdb'.
#
# Since this deals with modifying the partition table of the SD card and data
# may be lost, for this reason, you will be prompted if you want to proceed.
#
# Please understand that this script is only provided in the hopes that it will
# be useful to Technologic Systems customers and does not have any guarantees
# or warranties.  If you require additional assistance, custom engineering is
# available.  Take care and understand what you are doing!  If you're not 
# comfortable in running this script, then perhaps 'gparted' can be used.
#
# This script was tested by writing a factory 512MB SD image for the TS-7350 to
# a 2GB SD card in both JFS and EXT3 filesystem formats.

# CHECK FOR ROOT ACCESS
if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

# CHECK FOR COMMAND LINE ARGUMENT
if [ $# -lt 1 ]; then
   echo "Example Usage: $0 /dev/sdb"
   exit 1
fi

# INITIALIZE VARIABLES
TYPE=none

# CHECK DISK AND PARTITIONS
if [ -e $1 ]; then
	DISK=$1
	NUMBER=`fdisk -l $DISK | grep 83 | awk '{print $1}' | sed "s,$DISK,,g"`
	if [ -e $NUMBER ]; then
		echo "Valid TS partition not found!"
		echo "Exiting"
		exit 1
	fi
else
	echo "No disk found at ${1}!"
	echo "Exiting"
	exit 1
fi

expand_sd(){
	mkdir /mnt/tmp 2> /dev/null
	mount ${DISK}$NUMBER /mnt/tmp 2> /dev/null
	TYPE=`df -T | grep ${DISK}$NUMBER | awk '{print $2}'`
	umount ${DISK}$NUMBER 2> /dev/null

	ORIG=`fdisk -l $DISK | grep ${DISK}$NUMBER | awk '{ print $3 }'`
	SIZE=`fdisk -l $DISK | grep Disk | awk '{print $5}'`	
	UNITS=`fdisk -l $DISK | grep Units | awk '{print $9}'`
	END=`echo "($SIZE/$UNITS)-5" | bc`
	
	if [ $ORIG -gt $END ]; then
		echo "Original ($ORIG) is larger than end goal ($END)!"
		echo "Exiting"
		exit
	else	
		echo -n "Expanding ${DISK}$NUMBER from $ORIG to $END... "
		(
			{
				echo ,$END,0x83,-
			} | sfdisk -f $DISK -N$NUMBER 
		) >/dev/null 2>&1 </dev/null
		echo "done"
	fi
}

echo
echo "This program was created in hopes that it will be useful to Technologic "
echo "Systems customers.  There are no guarantees or warranties.  Please backup"
echo "your data before running this. Also, keep in mind that the JFS filesystem"
echo "can grow, but cannot shrink again." 
echo -e "Do you wish to proceed <y or n>? \c"
read WISH

if [ $WISH = "n" ] ; then
	echo "Exiting" 
	exit 1
fi
echo "Proceeding..."

expand_sd

if [ $TYPE == "jfs" ]; then
	echo "JFS!"
	exit 1
	# CHECK DEPENDENCIES
	which jfs_mkfs >/dev/null 2>&1 </dev/null
	jfsutils=$?

	if [ $jfsutils -eq 1 ]; then
		echo "Missing dependency jfsutils!"
		echo "You may be able to install them using 'apt-get install jfsutils'"
		echo "Exiting"	
		exit 1
	fi

	echo -n "Resizing JFS disk ${DISK}$NUMBER to fill new size of the partition... "
	(	
		mkdir /mnt/tmp
		mount ${DISK}$NUMBER /mnt/tmp
		mount -o remount,resize /mnt/tmp
		umount ${DISK}$NUMBER
	) >/dev/null 2>&1 </dev/null
	echo "done"
elif [ $TYPE == "ext3" ]; then
        echo "EXT3!"
	exit 1
	echo -n "Resizing EXT3 disk ${DISK}$NUMBER to fill new size of the partition... "
        (
                e2fsck -f ${DISK}$NUMBER
                resize2fs ${DISK}$NUMBER
        ) >/dev/null 2>&1 </dev/null
        echo "done"
elif [ $TYPE == "none" ]; then
	echo "Valid partition not found!"
	echo "Exiting"
	exit 1
else
	echo "Only JFS and EXT3 filesystem types are supported!"
	echo "Exiting"
	exit 1
fi