From c4b654c753f4e29a45a10d8bb9a1a84316c05c19 Mon Sep 17 00:00:00 2001
From: ferrreo <harderthanfire@gmail.com>
Date: Wed, 30 Aug 2023 19:47:47 +0100
Subject: [PATCH] Create update-initramfs

---
 update-initramfs | 398 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 398 insertions(+)
 create mode 100644 update-initramfs

diff --git a/update-initramfs b/update-initramfs
new file mode 100644
index 0000000..8a0f597
--- /dev/null
+++ b/update-initramfs
@@ -0,0 +1,398 @@
+#!/bin/sh
+
+BOOTDIR=/boot
+CONF=/etc/initramfs-tools/update-initramfs.conf
+mode=""
+version=""
+update_initramfs=yes
+backup_initramfs=no
+
+set -e
+
+[ -r ${CONF} ] && . ${CONF}
+
+if [ -n "$DPKG_MAINTSCRIPT_PACKAGE" ] && [ $# = 1 ] && [ "$1" = -u ]; then
+	if dpkg-trigger --no-await update-initramfs; then
+		echo "update-initramfs: deferring update (trigger activated)"
+		exit 0
+	fi
+fi
+
+usage()
+{
+	cat << EOF
+
+Usage: update-initramfs {-c|-d|-u} [-k version] [-v] [-b directory]
+
+Options:
+ -k version	Specify kernel version or 'all'
+ -c		Create a new initramfs
+ -u		Update an existing initramfs
+ -d		Remove an existing initramfs
+ -b directory	Set alternate boot directory
+ -v		Be verbose
+
+See update-initramfs(8) for further details.
+
+EOF
+}
+
+usage_error()
+{
+	if [ -n "${1:-}" ]; then
+		printf "%s\\n\\n" "${*}" >&2
+	fi
+	usage >&2
+	exit 2
+}
+
+mild_panic()
+{
+	if [ -n "${1:-}" ]; then
+		printf "%s\\n" "${*}" >&2
+	fi
+	exit 0
+}
+
+panic()
+{
+	if [ -n "${1:-}" ]; then
+		printf "%s\\n" "${*}" >&2
+	fi
+	exit 1
+}
+
+verbose()
+{
+	if [ "${verbose}" = 1 ]; then
+		printf "%s\\n" "${*}"
+	fi
+}
+
+set_initramfs()
+{
+	initramfs="${BOOTDIR}/booster.img-${version}"
+}
+
+
+# backup initramfs while running
+backup_initramfs()
+{
+	[ ! -r "${initramfs}" ] && return 0
+	initramfs_bak="${initramfs}.dpkg-bak"
+	[ -r "${initramfs_bak}" ] && rm -f "${initramfs_bak}"
+	ln -f "${initramfs}" "${initramfs_bak}" \
+		|| cp -a "${initramfs}" "${initramfs_bak}"
+	verbose "Keeping ${initramfs_bak}"
+}
+
+# keep booted initramfs
+backup_booted_initramfs()
+{
+	initramfs_bak="${initramfs}.dpkg-bak"
+
+	# first time run thus no backup
+	[ ! -r "${initramfs_bak}" ] && return 0
+
+	# chroot with no /proc
+	[ ! -r /proc/uptime ] && rm -f "${initramfs_bak}" && return 0
+
+	# no kept backup wanted
+	[ "${backup_initramfs}" = "no" ] && rm -f "${initramfs_bak}" && return 0
+
+	# no backup yet
+	if [ ! -r "${initramfs}.bak" ]; then
+		mv -f "${initramfs_bak}" "${initramfs}.bak"
+		verbose "Backup ${initramfs}.bak"
+		return 0
+	fi
+
+	# keep booted initramfs
+	boot_initramfs=
+	uptime_days=$(awk '{printf "%d", $1 / 3600 / 24}' /proc/uptime)
+	if [ -n "$uptime_days" ]; then
+		boot_initramfs=$(find "${initramfs}.bak" -mtime "+${uptime_days}")
+	fi
+	if [ -n "${boot_initramfs}" ]; then
+		mv -f "${initramfs_bak}" "${initramfs}.bak"
+		verbose "Backup ${initramfs}.bak"
+		return 0
+	fi
+	verbose "Removing current backup ${initramfs_bak}"
+	rm -f "${initramfs_bak}"
+}
+
+# nuke generated copy
+remove_initramfs_bak()
+{
+	[ -z "${initramfs_bak:-}" ] && return 0
+	rm -f "${initramfs_bak}"
+	verbose "Removing ${initramfs_bak}"
+}
+
+
+generate_initramfs()
+{
+	echo "update-initramfs: Generating ${initramfs}"
+	OPTS="-o"
+	if [ "${verbose}" = 1 ]; then
+		OPTS="-v ${OPTS}"
+	fi
+	# shellcheck disable=SC2086
+	if booster build --force --kernel-version "${version}" "${initramfs}.new" ; then
+		mv -f "${initramfs}.new" "${initramfs}"
+		# Guard against an unclean shutdown
+		sync -f "${initramfs}"
+	else
+		mkinitramfs_return="$?"
+		remove_initramfs_bak
+		rm -f "${initramfs}.new"
+		echo "update-initramfs: failed for ${initramfs} with $mkinitramfs_return." >&2
+		exit $mkinitramfs_return
+	fi
+}
+
+# Invoke bootloader
+run_bootloader()
+{
+	# invoke policy conformant bootloader hooks
+	if [ -d /etc/initramfs/post-update.d/ ]; then
+		run-parts --arg="${version}" --arg="${initramfs}" \
+			/etc/initramfs/post-update.d/
+		return 0
+	fi
+}
+
+# ro /boot is not modified
+ro_boot_check()
+{
+	# check irrelevant inside of a chroot
+	if [ ! -r /proc/mounts ] || ischroot; then
+		return 0
+	fi
+
+	# shellcheck disable=SC1004
+	boot_opts=$(awk '/boot/{if ((match($4, /^ro/) || match($4, /,ro/)) \
+		&& $2 == "/boot") print "ro"}' /proc/mounts)
+	if [ -n "${boot_opts}" ]; then
+		echo "W: /boot is ro mounted." >&2
+		echo "W: update-initramfs: Not updating ${initramfs}" >&2
+		exit 0
+	fi
+}
+
+get_sorted_versions()
+{
+	version_list="$(
+		linux-version list |
+		while read -r version; do
+		     test -e "${BOOTDIR}/initrd.img-$version" && echo "$version"
+		done |
+		linux-version sort --reverse
+		)"
+	verbose "Available versions: ${version_list}"
+}
+
+set_current_version()
+{
+	if [ -f "/boot/initrd.img-$(uname -r)" ]; then
+		version=$(uname -r)
+	fi
+}
+
+set_linked_version()
+{
+	linktarget=
+	if [ -e /initrd.img ] && [ -L /initrd.img ]; then
+		linktarget="$(basename "$(readlink /initrd.img)")"
+	fi
+
+	if [ -e /boot/initrd.img ] && [ -L /boot/initrd.img ]; then
+		linktarget="$(basename "$(readlink /boot/initrd.img)")"
+	fi
+
+	if [ -z "${linktarget}" ]; then
+		return
+	fi
+
+	version="${linktarget##initrd.img-}"
+}
+
+set_highest_version()
+{
+	get_sorted_versions
+	if [ -z "${version_list}" ]; then
+		version=
+		return
+	fi
+	# shellcheck disable=SC2086
+	set -- ${version_list}
+	version=${1}
+}
+
+create()
+{
+	if [ -z "${version}" ]; then
+		usage_error "Create mode requires a version argument"
+	fi
+
+	set_initramfs
+
+	generate_initramfs
+
+	run_bootloader
+}
+
+update()
+{
+	if [ "${update_initramfs}" = "no" ]; then
+		echo "update-initramfs: Not updating initramfs."
+		exit 0
+	fi
+
+	if [ -z "${version}" ]; then
+		set_highest_version
+	fi
+
+	if [ -z "${version}" ]; then
+		set_linked_version
+	fi
+
+	if [ -z "${version}" ]; then
+		set_current_version
+	fi
+
+	if [ -z "${version}" ]; then
+		verbose "Nothing to do, exiting."
+		exit 0
+	fi
+
+	set_initramfs
+
+	ro_boot_check
+
+	backup_initramfs
+
+	generate_initramfs
+
+	run_bootloader
+
+	backup_booted_initramfs
+}
+
+delete()
+{
+	if [ -z "${version}" ]; then
+		usage_error "Delete mode requires a version argument"
+	fi
+
+	set_initramfs
+
+	echo "update-initramfs: Deleting ${initramfs}"
+
+	rm -f "${initramfs}" "${initramfs}.bak"
+}
+
+# Defaults
+verbose=0
+
+##
+
+OPTIONS=$(getopt -o "k:cudvtb:h?" --long help -n "$0" -- "$@") || usage_error
+
+eval set -- "$OPTIONS"
+
+while true; do
+	case "$1" in
+	-k)
+		version="$2"
+		shift 2
+		;;
+	-c)
+		mode="c"
+		shift
+		;;
+	-d)
+		mode="d"
+		shift
+		;;
+	-u)
+		mode="u"
+		shift
+		;;
+	-v)
+		verbose="1"
+		shift
+		;;
+	-t)
+		# accepted for compatibility, but ignored
+		shift
+		;;
+	-b)
+		BOOTDIR="$2"
+		if [ ! -d "${BOOTDIR}" ]; then
+			echo "E: ${BOOTDIR} is not a directory." >&2
+			exit 1
+		fi
+		shift 2
+		;;
+	-h|-\?|--help)
+		usage
+		exit 0
+		;;
+	--)
+		shift
+		break
+		;;
+	esac
+done
+
+if [ $# -ne 0 ]; then
+	printf "Extra argument '%s'\\n\\n" "$1" >&2
+	usage_error
+fi
+
+# Validate arguments
+if [ -z "${mode}" ]; then
+	usage_error "You must specify at least one of -c, -u, or -d."
+fi
+
+if [ "${version}" = "all" ] \
+	|| { [ "${update_initramfs}" = "all" ] && [ -z "${version}" ]; }; then
+	case "${mode}" in
+	c)
+		version_list="$(linux-version list)"
+		;;
+	d | u)
+		get_sorted_versions
+		;;
+	esac
+	if [ -z "${version_list}" ]; then
+		verbose "Nothing to do, exiting."
+		exit 0
+	fi
+
+	OPTS="-b ${BOOTDIR}"
+	if [ "${verbose}" = "1" ]; then
+		OPTS="${OPTS} -v"
+	fi
+	for u_version in ${version_list}; do
+		verbose "Execute: ${0} -${mode} -k \"${u_version}\" ${OPTS}"
+		# shellcheck disable=SC2086
+		"${0}" -${mode} -k "${u_version}" ${OPTS}
+	done
+	exit 0
+fi
+
+
+case "${mode}" in
+	c)
+		create
+		;;
+	d)
+		delete
+		;;
+	u)
+		update
+		;;
+esac