#!/bin/bash
# Creates a new virtual machine from the given stage4 tarball

DOMNAME="$1"
STAGE_TBZ="$2"
VMNAME=$(echo "${DOMNAME}" | tr '[:upper:]' '[:lower:]')
VM_FQDN="${VMNAME}.$(hostname -d)"

if [[ -z $STAGE_TBZ || -z $VMNAME ]]; then
	echo "Usage: $(basename $0) <vmname> <stage4-tarball>" >&2
	exit 2
fi

: ${VG:=vmachines}
: ${POOL:=LVM}
: ${DOMXML_TMPL:=/etc/libvirt/qemu/_template.xml}
: ${MOUNTPOINT:=/mnt/new_vmachine}
: ${PORTAGE_PROFILE:="default/linux/amd64/13.0"}
: ${VM_TZ:=America/Chicago}


quit() {
	exit "$@"
}

cleanup() {
	local mnt
	echo "Failed! Cleaning up..."
	sync ; sync ; sync
	if [ -n "${MOUNTPOINT}" ]; then
		for d in home usr var run tmp ""; do
			mnt="${MOUNTPOINT}"/$d
			mountpoint -q "${mnt}" && umount -l "${mnt}"
		done
	fi
	vgchange -an ${VMNAME}
	lvchange -an ${VG}/${VMNAME}
	virsh -c qemu:///system vol-delete ${VMNAME} ${POOL}
}


while [[ -z ${VM_ROOTPW} ]]; do
	read -sp 'New VM root password: ' VM_ROOTPW
	echo
	read -sp 'Confirm root password: ' confirm_rootpw
	echo
	if [[ ${VM_ROOTPW} != ${confirm_rootpw} ]]; then
		echo "Passwords don't match" >&2
		unset VM_ROOTPW
	fi
done

set -e

PORTDIR=$(portageq envvar PORTDIR)
DISTDIR=$(portageq envvar DISTDIR)
PKGDIR=$(portageq envvar PKGDIR)

if lvdisplay ${VG}/${VMNAME} >/dev/null 2>&1; then
	echo "ERROR: Logical volume ${VMNAME} already exists in group ${VG}" >&2
	exit 1
fi

echo "Creating storage volume..."
virsh -c qemu:///system vol-create-as ${POOL} ${VMNAME} 2G

echo "Creating LVM volumes..."
pvcreate /dev/${VG}/${VMNAME}
vgcreate ${VMNAME} /dev/${VG}/${VMNAME}
lvcreate -nroot -L100M ${VMNAME}
lvcreate -nhome -L200M ${VMNAME}
lvcreate -nvar -L400M ${VMNAME}
lvcreate -nusr -l100%FREE ${VMNAME}

trap "quit" INT TERM
trap "cleanup" EXIT

echo "Creating XFS filesystems..."
for fs in root home usr var; do
	mkfs.xfs -L$fs -q /dev/${VMNAME}/$fs
done

echo "Mounting filesystems..."
[[ ! -d "${MOUNTPOINT}" ]] && mkdir -p "${MOUNTPOINT}"
mount /dev/${VMNAME}/root "${MOUNTPOINT}"
for fs in home usr var; do
	mkdir "${MOUNTPOINT}"/$fs
	mount /dev/${VMNAME}/$fs "${MOUNTPOINT}"/$fs
done
mkdir "${MOUNTPOINT}"/run
mount -t tmpfs tmpfs "${MOUNTPOINT}"/run

echo "Extracting stage tarball..."
tar -xjpf "${STAGE_TBZ}" -C "${MOUNTPOINT}"

echo "Setting hostname..."
sed -i "s/localhost/${VMNAME}/" "${MOUNTPOINT}"/etc/conf.d/hostname

echo "Setting time zone..."
rm -f "${MOUNTPOINT}"/etc/localtime
ln -s /usr/share/zoneinfo/${VM_TZ} "${MOUNTPOINT}"/etc/localtime
echo ${VM_TZ} > "${MOUNTPOINT}"/etc/timezone

echo "Configuring network..."
cat <<EOF > "${MOUNTPOINT}"/etc/conf.d/net
config_eth0="dhcp"
dhcpcd_eth0="-q"
EOF
ln -s net.lo "${MOUNTPOINT}"/etc/init.d/net.eth0
ln -s /etc/init.d/net.eth0 "${MOUNTPOINT}"/etc/runlevels/default/

for keytype in dsa rsa ecdsa; do
	key="${MOUNTPOINT}"/etc/ssh/ssh_host_${keytype}_key
	echo "Creating ${keytype} SSH host key..."
	ssh-keygen -t ${keytype} -f "${key}" -N '' || true
done

echo "Configuring fstab..."
cat << EOF > "${MOUNTPOINT}"/etc/fstab
/dev/${VMNAME}/root	/		xfs		ro,noatime	0 1
/dev/${VMNAME}/usr	/usr		xfs		ro,noatime	0 2
/dev/${VMNAME}/var	/var		xfs		noatime		0 2
/dev/${VMNAME}/home	/home		xfs		noatime		0 2
tmpfs			/tmp		tmpfs		defaults	0 0
EOF

echo "Creating read-only root filesystem compatibility symlinks..."
rm -f "${MOUNTPOINT}"/etc/{resolv,ntp}.conf
rm -f "${MOUNTPOINT}"/etc/mtab
ln -s /proc/self/mounts "${MOUNTPOINT}"/etc/mtab
ln -s /run/resolv.conf "${MOUNTPOINT}"/etc/resolv.conf
ln -s /run/ntp.conf "${MOUNTPOINT}"/etc/ntp.conf

echo "Setting root password..."
echo "root:${VM_ROOTPW}" | chroot "${MOUNTPOINT}" chpasswd

echo "Enabling serial console..."
sed -i 's/#s0/s0/' "${MOUNTPOINT}"/etc/inittab

trap - INT TERM EXIT

echo "Cleaning up..."
umount "${MOUNTPOINT}"/{run,usr,var,home,}
vgchange -an ${VMNAME}

echo "Creating libvirt domain..."
virsh -c qemu:///system define <(m4 -P -DNAME="${DOMNAME}" "${DOMXML_TMPL}")
echo "Starting virtual machine..."
virsh -c qemu:///system start ${DOMNAME}