#!/bin/bash

#
#	Leo Eraly <leo at unstable dot be>
#
echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
echo ""
echo "While running this script no other tasks should be performed on this system"
echo ""
echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"

INITIAL_CONFIG=/tmp/xen-config-start.tmp
HD_FILE_ROOT="/var/lib/xen/images"
CONFIG_ROOT="/etc/xen/vm/"

function write_initial_config()
{
# default xen vm configuration file

cat > $INITIAL_CONFIG << EOF
disk = [ 'file:/var/lib/xen/images/#NAME#/#VIRTUAL_DISK#,#VIRTUAL_DISK#,w', 'phy:/dev/hdc,hdb,r' ]
memory = 256
vcpus = 1
builder = 'linux'
name = '#NAME#'
vif = [ 'mac=#MAC#' ]
localtime = 0
on_poweroff = 'destroy'
on_reboot = 'restart'
on_crash = 'restart'
extra = ' TERM=xterm'
bootloader = '/usr/lib/xen/boot/domUloader.py'
bootentry = '#ROOT_PARTITION#:/boot/vmlinuz-xen,/boot/initrd-xen'
EOF

echo "Wrote $INITIAL_CONFIG"
}

# start of new random mac address 
MAC_START="00:16:3e"

#function to generate mac address
function generate_mac()
{
/usr/bin/perl << EOF

\$string = "0123456789abcdef";

\$k = (substr(\$string , rand(16) , 1)) . substr(\$string , rand(16) , 1);

print(\$k);
EOF

}

NEW_MAC="$MAC_START:$(generate_mac):$(generate_mac):$(generate_mac)"


function blocks_to_mb()
{
	K=$[$1/1024]
	echo $K
}

NEW_MACHINE_NAME=$(ls -1 /etc/xen/vm/ | tail -1 | awk -F [a-zA-Z] '{ print $3}')
NEW_MACHINE_NAME=$[$NEW_MACHINE_NAME+1]
NEW_MACHINE_NAME="vm$NEW_MACHINE_NAME"

#we need to have rsync installed
RSYNC_BIN=/usr/bin/rsync

test -x $RSYNC_BIN || echo "$RSYNC_BIN not installed";


ROOT_DEV=$(grep " / " /proc/mounts | grep -v rootfs | cut -d" " -f1)
VIRTUAL_DISK=$(echo $ROOT_DEV | sed -e s/[0-9]// | cut -d/ -f3 )
ROOT_PARTITION=$(echo $ROOT_DEV | sed -e s/\\/dev\\///)
ROOTFS=$(grep " / " /proc/mounts | grep -v rootfs | cut -d" " -f3)
ROOT_DEV_SIZE=$(sfdisk -s $ROOT_DEV)
ROOT_DEV_USED=$(df | grep "$ROOT_DEV" | tr -s " " ":" | cut -d: -f3)
ROOT_DEV_AVAIL=$(df | grep "$ROOT_DEV" | tr -s " " ":" | cut -d: -f4)
MAIN_DEV=$(echo $ROOT_DEV | sed -e "s/[0-9]//")

ROOT_CYLINDERS=$(sfdisk -q -l $MAIN_DEV 2> /dev/null | grep $ROOT_DEV | tail -1 | tr -s " " ":" | cut -d: -f 5)
ROOT_CYLINDERS=$(echo $ROOT_CYLINDERS | sed -e "s/[-|+]//")

SWAP_DEV=$(tail -1 /proc/swaps | cut -d" " -f1)
SWAP_DEV_SIZE=$(sfdisk -s $SWAP_DEV)
SWAP_CYLINDERS=$( sfdisk -q -l $MAIN_DEV 2> /dev/null | grep $SWAP_DEV | tail -1 | tr -s " " ":"  | cut -d: -f 4)
SWAP_CYLINDERS=$(echo $SWAP_CYLINDERS | sed -e "s/[-|+]//")


# this is added to the current size currently in use on the root device
EXTRA_SIZE=1000

NEW_ROOT_SIZE=$[$ROOT_DEV_USED+$EXTRA_SIZE+SWAP_DEV_SIZE]

echo "Partition which contains root fs: $ROOT_DEV"
echo "Type of root fs: $ROOTFS"
echo "Size of root partition (blocks): $ROOT_DEV_SIZE"
echo "Size of root partition currently in use (blocks): $ROOT_DEV_USED"
echo "Size of root partition in VM (blocks - to be created): $NEW_ROOT_SIZE"

if [ $NEW_ROOT_SIZE -lt $ROOT_DEV_AVAIL ]
then
	echo "We have enough space available. Continuing..."
else
	echo "We don't have enough space available to create a VM"
	echo "We need $NEW_ROOT_SIZE but only $ROOT_DEV_AVAIL available (blocks)"
	exit 1
fi

TEMP_ROOT_FILE=$(mktemp)

echo "Creating file ($TEMP_ROOT_FILE) which will hold new vm"

dd if=/dev/zero of=$TEMP_ROOT_FILE bs=1k count=$NEW_ROOT_SIZE

if [ $? -eq 0 ]
then
	echo "File was created successfully"
else
	"Failed to create file ($TEMP_ROOT_FILE)"
	rm $TEMP_ROOT_FILE
	exit 1
fi

echo "Setting up loopback device"

#get list of existing loop devices

LAST_LOOP=$(losetup -a | cut -d: -f1 | tail -1 | awk -F 'loop' '{print $2}')
LAST_LOOP=$[$LAST_LOOP+1]
LOOP_DEVICE="/dev/loop$LAST_LOOP"

if [ $LAST_LOOP -lt 7 ]
then
	echo "Creating loop device"
	losetup $LOOP_DEVICE $TEMP_ROOT_FILE
else
	echo "No available loop devices"
	exit 1
fi

if [ $? -eq 0 ]
then
	echo "Successfully created loop device under $LOOP_DEVICE"
else
	echo "Failed to create loop device"
	exit 1
fi

#create empty dos partition table
echo "Creating (msdos) disk label on $LOOP_DEVICE"
parted -s $LOOP_DEVICE mklabel msdos

if [ $? -eq 0 ]
then
	echo "Successfully created disk label on $LOOP_DEVICE"
else
	echo "Failed to create disk label"
	exit 1
fi

echo "Creating an initial partition table"

SWAP_MB=`blocks_to_mb "$SWAP_DEV_SIZE"`
parted -s $LOOP_DEVICE mkpartfs primary linux-swap 0 $SWAP_MB > /dev/null 2>&1

SWAP_MB=$[$SWAP_MB+1]
ROOT_MB=`blocks_to_mb "$NEW_ROOT_SIZE"`

parted -s $LOOP_DEVICE mkpart primary $SWAP_MB $ROOT_MB > /dev/null 2>&1

parted -s $LOOP_DEVICE print

echo "Creating device mappings for the partitions"

kpartx -a $LOOP_DEVICE > /dev/null 2>&1

if [ $? -eq 0 ]
then
	echo "Successfully created device mappings"
else
	echo "Failed to create device mappings"
	exit 1
fi

ROOT_MAPPING=$(kpartx -l $LOOP_DEVICE | tr -s " " ":" | cut -d: -f1 | tail -1)
ROOT_MAPPING="/dev/mapper/$ROOT_MAPPING"
SWAP_MAPPING=$(kpartx -l $LOOP_DEVICE | tr -s " " ":" | cut -d: -f1 | head -1)
SWAP_MAPPING="/dev/mapper/$SWAP_MAPPING"

echo "Creating root filesystem on $TEMP_ROOT_FILE ($ROOT_MAPPING)"

if [ -b "$ROOT_MAPPING" ]
then
	echo "Device mapping for root partition exists"	
else
	echo "No device mapping for root partition created"
	exit 1
fi

case "$ROOTFS" in
	reiserfs)
		mkfs.reiserfs -fff $ROOT_MAPPING > /dev/null 2>&1
	;;
	ext2|ext3)
		mkfs.ext3 -F $ROOT_MAPPING > /dev/null 2>&1
	;;
 	xfs)
		mkfs.xfs -f $ROOT_MAPPING > /dev/null 2>&1
	;;	
esac

if [ $? -eq 0 ]
then
	echo "Successfully created filesystem on $ROOT_MAPPING ($ROOTFS)"
else
	echo "Failed to create filesystem"
	exit 1
fi

echo "Creating swap on $SWAP_MAPPING"

if [ -b "$SWAP_MAPPING" ]
then
	echo "Device mapping for swap partition exists"	
else
	echo "No device mapping for swap partition created"
	exit 1
fi

mkswap $SWAP_MAPPING

if [ $? -eq 0 ]
then
	echo "Successfully created swap on $SWAP_MAPPING"
else
	echo "Failed to create swap"
	exit 1
fi

# now loopback mount the filesystem in a temporary directory
echo "Trying to (loopback) mount the filesystem"
TEMP_MOUNT_DIR=/mnt/xen-temp

if [ -d "$TEMP_MOUNT_DIR" ]
then
	echo "Temp mount dir: $TEMP_MOUNT_DIR exists"
else
	echo "Creating $TEMP_MOUNT_DIR"
	mkdir $TEMP_MOUNT_DIR
fi

mount -o loop $ROOT_MAPPING $TEMP_MOUNT_DIR

if [ $? -eq 0 ]
then
	echo "Successfully mounted $ROOT_MAPPING on $TEMP_MOUNT_DIR"
else
	echo "Failed to mount $TEMP_ROOT_FILE on $TEMP_MOUNT_DIR"
	exit 1
fi

# syncing root fs to virtual disk file
echo "Trying to sync the root fs to the virtual disk file"

$RSYNC_BIN -azvp --exclude=/proc --exclude=/sys --exclude=/mnt --exclude=/tmp --exclude=/var/lib/xen/images / $TEMP_MOUNT_DIR

if [ $? -eq 0 ]
then
	echo "Successfully synced"
	mkdir "$TEMP_MOUNT_DIR/mnt" "$TEMP_MOUNT_DIR/sys" "$TEMP_MOUNT_DIR/proc" "$TEMP_MOUNT_DIR/tmp"
else
	echo "Failed to sync root fs"
	exit 1
fi

umount $TEMP_MOUNT_DIR

if [ $? -eq 0 ]
then
	echo "Successfully unmounted $TEMP_MOUNT_DIR"
else
	echo "Failed to unmount $TEMP_MOUNT_DIR"
	exit 1
fi

echo "Creating images directory"
HD_DIR="$HD_FILE_ROOT/$NEW_MACHINE_NAME"
HD_FILE="$HD_FILE_ROOT/$NEW_MACHINE_NAME/$VIRTUAL_DISK"
CONFIG_FILE="$CONFIG_ROOT/$NEW_MACHINE_NAME"
mkdir -p $HD_DIR

if [ $? -eq 0 ]
then
	echo "Successfully created $HD_DIR"
else
	echo "Failed to create $HD_DIR"
	exit 1
fi

echo "Removing temporary device mappings"

kpartx -d $LOOP_DEVICE > /dev/null 2>&1

if [ $? -eq 0 ]
then
	echo "Successfully removed device mappings"
else
	echo "Failed to remove device mappings"
	exit 1
fi

echo "Removing loop devices"

losetup -d $LOOP_DEVICE > /dev/null 2>&1

if [ $? -eq 0 ]
then
	echo "Successfully removed loop device ($LOOP_DEVICE)"
else
	echo "Failed to remove loop device ($LOOP_DEVICE)"
	exit 1
fi

echo "Moving image file to permanent location ($VIRTUAL_DISK)"

mv $TEMP_ROOT_FILE $HD_FILE

if [ $? -eq 0 ]
then
	echo "Successfully moved image file to $HD_FILE"
else
	echo "Failed to move image file to $HD_FILE"
	exit 1
fi

echo "Writing configuration"

write_initial_config

echo "Writing configuration with following values"
echo "-------------------------------------------"
echo -e "Machine name\t\t : $NEW_MACHINE_NAME"
echo -e  "Mac address\t\t : $NEW_MAC"
echo -e "Hard disk file\t\t : $HD_FILE"
echo -e "Virtual disk name\t : $VIRTUAL_DISK"
echo -e "Root partition\t\t : $ROOT_PARTITION"

sed -e s/#NAME#/$NEW_MACHINE_NAME/g $INITIAL_CONFIG | sed -e s/#MAC#/$NEW_MAC/ | sed -e s/#VIRTUAL_DISK#/$VIRTUAL_DISK/g | sed -e s/#ROOT_PARTITION#/$ROOT_PARTITION/ > $CONFIG_FILE

if [ $? -eq 0 ]
then
	echo "Successfully created configuration file ($CONFIG_FILE)"
	rm $INITIAL_CONFIG
else
	echo "Failed to create configuration file ($CONFIG_FILE)"
	rm $INITIAL_CONFIG
	exit 1
fi

#/bin/rm $TEMP_ROOT_FILE