#!/bin/sh
set -o errexit

# Helper script for running FreeBSD under bhyve 
# Downloads images/ISOs from FreeBSD master site
# Maps in usb devices as desired to guest

# Global constants
dl_uri="https://download.freebsd.org/releases/"
work_dir="."
cpus="4"
memory="4096M"
# -E makes UEFI mode active in vmrun.sh
bios="-E"

usage() { 
	echo "Usage:"
	echo " $0 [-r <BETA|ALPHA|RELEASE>] [-u <USBDevice String>]" 
	echo "    [-t <VM|ISO>]" 
	echo ""
	echo " -r will select the latest BETA/ALPHA/RELEASE version available for download"
	echo " -t will select a VM_IMAGE (Default) or ISO (Install from scratch) for download"
	echo " -u will optionally enable passthrough of specific USB device from HOST to GUEST"
	exit 1
}

# If variable not defined, define default. 
r="RELEASE"
t="VM"

while getopts ":a:r:u:t:" opt; do
	case "${opt}" in
		r)
			r=${OPTARG}
			# If it does not match BETA or ALPHA set to RELEASE
			[ ${r} = "BETA" -o ${r} = "ALPHA" ] || r="RELEASE"
			;;
		u)
			u=${OPTARG}
			;;
		t)
			t=${OPTARG}
			# Only support VM and ISO at the moment.
			[ ${t} = "VM" -o ${t} = "ISO" ] || t="VM"
			;;
		*)
			usage
			;;
	esac
done
shift $((OPTIND-1))

# Handle the architecture specific variables and arguments
arch="$(sysctl -n hw.machine_arch)"
archvariant="${arch}"
kldload -n vmm
pkg info edk2-bhyve || pkg install -y edk2-bhyve

validate-sha512() {
	set +o errexit
	[ -z "${1}" -o ! -s ${1} ] && echo "No file ${1} for hash verification" && exit 1
	echo "Validating SHA512 CHECKSUM..."
	# We are cheating a bit and just using file globs so we don't need to pass in exact CHECKSUM filename
	expect_hash=$(grep ${1} CHECKSUM.SHA512* | cut -d "=" -f 2 | tr -d ' ')
	#echo "expect_hash: ${expect_hash}"
	actual_hash=$(sha512sum --quiet ${1} | tr -d ' ')
	#echo "actual_hash: ${actual_hash}"
	if [ "${expect_hash}" != "${actual_hash}" ] ; then
		printf "Failure validating hash on ${1}. \nExpect: ${expect_hash} \nActual: ${actual_hash}\n" 
		exit 1
	fi
	set -o errexit
}

fetch-image() {
	latest_version=$(curl -s ${dl_uri}VM-IMAGES/ \
		| grep -E -o -e "[0-9.]{3}[0-9]{1}-${r}[0-9]*/" | uniq | sort -gr | head -1 | tr -d '/')
	image_file="FreeBSD-${latest_version}-${archvariant}-ufs.raw"
	echo "Getting ready to fetch and/or start ${image_file}"
	if [ ! -s ${image_file} ] ; then
		fetch "${dl_uri}VM-IMAGES/${latest_version}/${arch}/Latest/${image_file}.xz" "${dl_uri}VM-IMAGES/${latest_version}/${arch}/Latest/CHECKSUM.SHA512"
		validate-sha512 ${image_file}.xz 
		unxz ${image_file}.xz
		qemu-img resize ${image_file} +45G
	fi
}

fetch-iso() {
	toplevel_version=$(curl -s ${dl_uri}VM-IMAGES/ \
		| grep -E -o -e "[0-9.]{3}[0-9]{1}-${r}[0-9]*/" | uniq | sort -gr | \
		head -1 | tr -d '/' | sed s/-${r}[0-9]*//1)
	#echo "toplevel_version: ${toplevel_version}"
	latest_version=$(curl -s ${dl_uri}ISO-IMAGES/${toplevel_version}/ \
		| grep -E -o -e "[0-9.]{3}[0-9]{1}-${r}[0-9]*" | uniq | sort -gr | head -1 | tr -d '/')
	#echo "latest_version: ${latest_version}"
	iso_file="FreeBSD-${latest_version}-${archvariant}-bootonly.iso"
	echo "Getting ready to fetch and/or start ${iso_file}"
	iso_boot_cli="-i -I ${iso_file}"
	image_file="FreeBSD-${latest_version}-${archvariant}-ufs.raw"
	iso_dl_uri="${dl_uri}ISO-IMAGES/${toplevel_version}/${iso_file}"
	checksum_dl_uri="${dl_uri}ISO-IMAGES/${toplevel_version}/CHECKSUM.SHA512-FreeBSD-${latest_version}-${archvariant}"

	if [ ! -s ${iso_file} ] ; then
		fetch "${iso_dl_uri}.xz" "${checksum_dl_uri}"
		validate-sha512 ${iso_file}.xz 
		unxz ${iso_file}.xz
	fi
	if [ ! -s ${image_file} ] ; then
		truncate -s 45G ${image_file}
	else
		read -p "You selected ISO Install with an existing disk image ${image_file}.  Do you wish to remove the existing file and recreate a blank disk file ? (y/n): " overwrite
		if [ "${overwrite}" = "y" -o "${overwrite}" = "Y" ] ; then
			rm ${image_file} 
			truncate -s 45G ${image_file}
		fi
	fi
}

setup-usb-passthrough() {
	echo "Attempting to passthrough usb host device based on query string: ${u}"
	usb_map_count=$(usbconfig | grep -cie ${u})
	[ ${usb_map_count} -ne 1 ] && \
		echo "Total devices matched: ${usb_map_count} is not equal to 1, please refine." && \
		usbconfig && exit 1
	usb_map=$(usbconfig | grep -ie ${u} | grep -E -o -e "[0-9]+\.[0-9]+")
	#echo "usb_map: ${usb_map}"
	usb_map_bus=$(echo ${usb_map} | grep -E -o -e "^[0-9]+")
	usb_map_addr=$(echo ${usb_map} | grep -E -o -e "[0-9]+$")
	usb_qemu_cli="-device usb-host,hostbus=${usb_map_bus},hostaddr=${usb_map_addr},id=${u}"
	echo "Mapping usb device $(usbconfig | grep -ie ${u}) into the guest."
	#echo "usb_qemu_cli = ${usb_qemu_cli}"
	echo -n "In qemu monitor, you can inspect attached usb guest devices with \"info usb\" "
	echo "command, or delete the usb device mapping with \"device_del ${u}\""
}

[ ${t} = "VM" ] && fetch-image
[ ${t} = "ISO" ] && fetch-iso
[ ! -z "${u}" ] && setup-usb-passthrough

# Safety check.
set +o errexit
ps -aux | grep -v -e grep -e start_bhyve | grep -cq bhyve && \
	echo "Bhyve is already running. Shutdown the guest, then retry." && exit 1

# Cleanup tap0 interfaces that are not in use anymore.
ifconfig tap0 2>/dev/null | grep -cq -e "Opened by PID" || ifconfig tap0 destroy 2>/dev/null || true
set -o errexit
echo "Starting Bhyve using vmrun.sh in background..."

vmrun.sh -m ${memory} -c ${cpus} \
	${bios} \
	${iso_boot_cli} \
	-d ${work_dir}/${image_file} \
	-t tap0 \
	${image_file}
echo "Connect to guest console (telnet localhost 4444), or qemu monitor (telnet localhost 4445)"
if [ ${t} = "ISO" ] ; then
	#telnet localhost 4444
fi