#!/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.
# It depends on tools such as sfdisk, which is part of core utilities
# of Linux.  If working with the JFS filesystem, jfsutils is another
# dependency.  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 for input before
# the script proceeds.
#
# 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 or support of any kind.  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' is right for you.
#
# This script was tested by writing a factory 512MB SD image for the TS-7350
# to both a 2GB and 16GB SD card in both JFS and EXT3 filesystem formats.

# CHECK FOR ROOT ACCESS
if [ `id -u` -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=`ls -l ${DISK}* | tail -n 1 | awk '{print $NF}' | sed "s,$DISK,,g"`
	NUMBER=`fdisk -l $DISK | grep 83 | tail -1 | awk '{print $1}' | sed "s,$DISK,,g"`
	if [ ! -e ${DISK}$NUMBER ]; then
		echo "Valid T.S. partition not found!"
		echo "The script attempted to find the last partition with id of 0x83 but couldn't find it."
		echo "Verify with \"fdisk -l\" as root."
		echo "Exiting"
		exit 1
	fi

	mount | grep $DISK > /dev/null
	if [ $? -eq 0 ]; then
		echo "Please unmount $DISK and re-run $0."
		exit 1
	fi

	mount | grep "/mnt/tmp" > /dev/null
	if [ $? -eq 0 ]; then
		echo "This script plans on using /mnt/tmp as mount point for SD card,"
		echo "but /mnt/tmp is a mount point for something else currently."
		echo "Please unmount it and re-run $0."
		exit 1
	fi

	mkdir /mnt/tmp
	mount ${DISK}$NUMBER /mnt/tmp 2> /dev/null
	TYPE=`df -T /mnt/tmp | tail -n 1 | awk '{print $2}'`
	umount ${DISK}$NUMBER 2> /dev/null
	rmdir /mnt/tmp 2> /dev/null

else
	echo "No disk found at ${1}!"
	echo "Exiting"
	exit 1
fi

#########################################
# Final Check and Messages
#########################################
goodbye(){
	echo -n "Running filesystem check on ${DISK}$NUMBER..."
	fsck -f ${DISK}$NUMBER >/dev/null 2>&1 </dev/null
	echo "done"

	sync
	echo "It is now safe to remove and use the SD card. Enjoy!" 
	exit 0
}

#########################################
# STEP 1 of 2:
#  Move partition boundary to end of disk
#########################################
move_part_bound(){
	ORIG=`fdisk -l $DISK | grep ${DISK}$NUMBER | awk '{print $3}'`
	TOTAL_CYLINDERS=`fdisk -lu $DISK | grep total | awk '{print $5}'`
	START_CYLINDER=`fdisk -l $DISK | grep ${DISK}$NUMBER | awk '{print $2}'`
	END=`echo "$TOTAL_CYLINDERS-$START_CYLINDER" | bc`

	if [ $ORIG -gt $END ]; then
		echo "Warning: Original ($ORIG) is larger than end goal ($END)!"
		echo "   Chances are, this disk is already as large as it can be,"
		echo "   but this script will continue anyways."
	fi

echo -n "Moving partition boundary of ${DISK}$NUMBER from $ORIG to $END (# cylinders)... "
(
sfdisk -i --force -f $DISK -N $NUMBER << EOF
,$END,0x83,-
EOF
) >/dev/null 2>&1 </dev/null
		echo "done"
}

#########################################
# STEP 2 of 2:
#  Expand filesystem to end of partition
#########################################
expand_fs(){
	if [ $TYPE = "jfs" ]; then
		# CHECK DEPENDENCIES
		which jfs_mkfs >/dev/null 2>&1 </dev/null
		jfsutils=$?

		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
			rmdir /mnt/tmp
		) >/dev/null 2>&1 </dev/null
		echo "done"
		goodbye

	elif [ $TYPE = "ext3" ]; then
		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"
		goodbye

	elif [ $TYPE = "none" ]; then
		echo "Valid partition type not found!"
		echo "Supported: ext3, jfs"
		echo "Exiting"
		exit 1

	else
		echo "Only JFS and EXT3 filesystem types are supported!"
		echo "Exiting"
		exit 1
	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."

if [ $TYPE == "jfs" ]; then
	echo
	echo "Also, keep in mind that the JFS filesystem can grow, but cannot shrink."
	echo
fi

echo -n "Do you wish to proceed? Type \"yes\" or \"no\" "
read WISH

case "$WISH" in
	"no")
		echo "Exiting"
		exit 1
		;;
	"yes")
		move_part_bound
		expand_fs
		;;
	*)
		echo "Exiting"
		exit 1
		;;
esac