Index: usr.sbin/efi-update-loader/efi-update-loader.8
===================================================================
--- /dev/null
+++ usr.sbin/efi-update-loader/efi-update-loader.8
@@ -0,0 +1,68 @@
+\"
+.\" Copyright (c) 2019 Rebecca Cran <bcran@freebsd.org>.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd March 12, 2019
+.Dt EFI-UPDATE-LOADER 8
+.Os
+.Sh NAME
+.Nm efi-update-loader
+.Nd Update an EFI System Partition with a FreeBSD loader
+.Sh SYNOPSIS
+.Nm
+.Op Fl d Ar device
+.Op Fl l Ar loader
+.Sh DESCRIPTION
+This program updates the
+.Dq Unified Extensible Firmware Interface
+.Pq UEFI
+.Dq EFI System Partition
+.Pq ESP
+with a new FreeBSD loader.efi file.
+
+The ESP is a FAT12, FAT16 or FAT32 filesystem that is used by the UEFI system
+firmware to load and run OS boot loaders that are compiled as
+.Dq Portable Executable
+.Pq PE
+binaries. The UEFI Boot Manager, which can be configured with the
+.Xr efibootmgr 8
+utility, contains entries which point to the location of the boot loader
+within the ESP.
+.Pp
+The following options are available:
+.Bl -tag -width indent
+.It Fl d Ar device
+Specify the device to use as the ESP.
+.It Fl l Ar loader
+Specify the file to install as the FreeBSD boot loader. This should normally
+be /boot/loader.efi, but could also for example be /boot/loader_4th.efi etc.
+.Sh SEE ALSO
+.Xr efibootmgr 8 ,
+.Xr efivar 8
+.Sh HISTORY
+The
+.Nm
+utility first appeared in
+.Fx 13.0
Index: usr.sbin/efi-update-loader/efi-update-loader.sh
===================================================================
--- /dev/null
+++ usr.sbin/efi-update-loader/efi-update-loader.sh
@@ -0,0 +1,212 @@
+#!/bin/sh
+#
+# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+#
+# Copyright (c) 2019 Rebecca Cran <bcran@FreeBSD.org>.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $FreeBSD$
+
+set -e
+
+get_uefi_bootname() {
+
+    case ${TARGET:-$(uname -m)} in
+        amd64) echo bootx64 ;;
+        arm64) echo bootaa64 ;;
+        i386) echo bootia32 ;;
+        arm) echo bootarm ;;
+        *)
+		echo "machine type $(uname -m) doesn't support UEFI"
+		exit 1
+		;;
+    esac
+}
+
+ 
+clean_up() {
+	if [ -z "${mntpt}" ]; then
+		exit 1
+	fi
+
+	if mount | grep -q "${mntpt}" ; then
+		umount "${mntpt}"
+	fi
+
+	if [ -d "${mntpt}" ]; then
+		rmdir "${mntpt}"
+	fi
+}
+
+
+bootefi_is_freebsd() {
+	efibootname=$(get_uefi_bootname)
+
+	if [ -f "${mntpt}/efi/boot/${efibootname}.efi" ]; then
+		boot1asbootefi=$(grep "FreeBSD EFI boot block" "${mntpt}/efi/boot/${efibootname}.efi") || true
+		if [ -n "${boot1asbootefi}" ]; then
+			echo "true"
+		fi
+	fi
+}
+
+
+get_freespace_on_esp() {
+	df -k "${mntpt}" | tail -1 | awk '{print $4}'
+}
+
+
+copyloader() {
+	mntpt=$(mktemp -d /tmp/esp.XXXXXX)
+
+	mount -t msdosfs "$espdev" "${mntpt}"
+
+	ldrsize=$(stat -f %z "${loader}")
+	# Convert to KB
+	ldrsize=$((ldrsize / 1024))
+
+	efibootname=$(get_uefi_bootname)
+
+	if [ ! -d "${mntpt}/EFI" ]; then
+		mkdir "${mntpt}/EFI"
+	fi
+
+	if [ ! -d "${mntpt}/EFI/FreeBSD" ]; then
+		mkdir "${mntpt}/EFI/FreeBSD"
+	fi
+
+	if [ -n "$(bootefi_is_freebsd)" ]; then
+
+		echo "Moving FreeBSD bootx64.efi to /EFI/FreeBSD/${efibootname}-old.efi"	
+		mv "${mntpt}/EFI/BOOT/${efibootname}.efi" "${mntpt}/EFI/FreeBSD/${efibootname}-old.efi"
+	fi
+
+	if [ -f "${mntpt}/EFI/FreeBSD/loader.efi" ]; then
+		existing_ldr_size=$(stat -f %z "${mntpt}/EFI/FreeBSD/loader.efi")
+		existing_ldr_size=$((existing_ldr_size / 1024))
+	fi
+
+	if [ -f "${mntpt}/efi/freebsd/loader.efi" ] && ! cmp -sz "${loader}" "${mntpt}/efi/freebsd/loader.efi"; then
+		# Check we have enough free space
+		if [ ! -e "${mntpt}/EFI/FreeBSD/loader-old.efi" ] && [ $(($(get_freespace_on_esp))) -lt ${existing_ldr_size} ] ; then
+			echo "Insufficient space on ESP to back up loader.efi; skipping backup"
+		else
+			echo "Backing up /EFI/FreeBSD/loader.efi to /EFI/FreeBSD/loader-old.efi"
+			cp "${mntpt}/EFI/FreeBSD/loader.efi" "${mntpt}/EFI/FreeBSD/loader-old.efi"
+		fi
+	fi
+
+	if [ -e "${mntpt}/EFI/FreeBSD/loader.efi" ]; then
+		spaceneeded=$((existing_ldr_size - ldrsize))
+	else
+		spaceneeded=${ldrsize}
+	fi
+
+	if [ $(($(get_freespace_on_esp))) -lt ${spaceneeded} ]; then
+		echo "Error: Insufficient space on ESP ${espdev} to install ${loader}."
+		eval clean_up
+		exit 1
+	fi
+
+	echo "Copying ${loader} to /EFI/FreeBSD/loader.efi"
+	cp "${loader}" "${mntpt}/EFI/FreeBSD/loader.efi"
+
+	if ! efibootmgr -v | grep -qi "EFI/FreeBSD/loader.efi" ; then
+		echo "Boot Option for FreeBSD doesn't exist: it's recommended to run efibootmgr. e.g.:"
+		echo "  efibootmgr -c -a -L FreeBSD -l /mnt/EFI/FreeBSD/loader.efi"
+	fi
+
+	umount "${mntpt}"
+	rmdir "${mntpt}"
+}
+
+
+usage() {
+	printf 'usage: %s -d [espdev] -l [loader]\n' "${progname}"
+	printf '\t-d ESP device\n'
+	printf '\t-l FreeBSD EFI loader\n'
+	exit 0
+}
+
+
+progname=$0
+loader=/boot/loader.efi
+espdev=
+
+while getopts "d:l:h" opt; do
+    case "$opt" in
+	d)
+	    espdev=${OPTARG}
+	    ;;
+	l)
+	    loader=${OPTARG}
+	    ;;
+	?)
+            usage
+            ;;
+    esac
+done
+
+trap clean_up 1 2 15 EXIT
+
+if [ -z "${espdev}" ]; then
+
+	mntpt=$(mktemp -d /tmp/esp.XXXXXX)
+
+	for disk in $(sysctl -n kern.disks); do
+		espindexes=$(gpart show "${disk}" 2> /dev/null | grep efi | awk '{print $3}')
+		for idx in ${espindexes}; do
+			if [ -e "/dev/${disk}p${idx}" ]; then
+				dev=/dev/${disk}p${idx}
+			elif [ -e "/dev/${disk}s${idx}" ]; then
+				dev=/dev/${disk}s${idx}
+			fi
+
+			if mount -t msdosfs "${dev}" "${mntpt}" 2> /dev/null ; then
+
+				if [ -n "$(bootefi_is_freebsd)" ] || [ -e "${mntpt}/efi/freebsd/loader.efi" ]; then
+					espdev=${dev}
+					echo "Found FreeBSD ESP device ${espdev}"
+				fi
+	
+				umount "${mntpt}"
+			fi
+		done
+	done
+
+	rmdir "${mntpt}"
+
+	if [ -z "${espdev}" ]; then
+		echo "Error: could not detect ESP containing FreeBSD loader to update"
+		exit 1
+	fi
+fi
+
+if [ -z "${espdev}" ]; then
+	eval usage	
+	exit 1
+fi
+
+eval copyloader "${espdev}" "${loader}"
+
+trap 1 2 15 EXIT