#!/bin/sh

ROOT=${1:-/dev/root}

fail() { echo "growroot: FAIL:" "$@" 1>&2; exit 1; }
msg() { echo "$@"; }

# figure out what disk ROOT is on
{ [ ! -L "${ROOT}" ] && rootdev=${ROOT} || rootdev=$(readlink -f "${ROOT}") ; } ||
	fail "failed to get target of link for ${ROOT}"

case "${rootdev}" in
	*[0-9]) : ;;
	# the root is a disk, not a partition (does not end in a digit)
	# no need to do anything in this case, kernel already knows the full size.
    *) exit 0;;
esac

# remove all consective numbers from the end of rootdev to get 'rootdisk'
rootdisk=${rootdev}
while [ "${rootdisk%[0-9]}" != "${rootdisk}" ]; do
	rootdisk=${rootdisk%[0-9]};
done
partnum=${rootdev#${rootdisk}}

# if the basename of the root device (ie 'xvda1' or 'sda1') exists
# in /sys/block/ then it is a block device, not a partition
# (xen xvda1 is an example of such a funny named block device)
[ -e "/sys/block/${rootdev##*/}" ] && exit 0

# if growpart fails, exit. its failure messages should go
# to stderr, so they'll get to the console
out=$(growpart "${rootdisk}" "${partnum}")
ret=$?

# if growpart output starts with 'CHANGED:' then it did something.
# anything else, exit
case "$ret" in
	0|1) echo "GROWROOT: $out";;
	*)
		echo "$out";
		exit $ret;;
esac

# write to /etc/grownroot-grown.
{ date --utc > "${rootmnt}/etc/growroot-grown" ; } >/dev/null 2>&1 || :

# vi: ts=4 noexpandtab