umorpha-boxes/modules/umorpha-disk.sh

#!/hint/bash -euE
# Copyright (C) 2023  Umorpha Systems
# SPDX-License-Identifier: AGPL-3.0-or-later

packages+=(
	# Functionality
	sudo

	# Experience
	less
	bash-completion
	rxvt-unicode-terminfo
)

pre_install+=(10:umorpha-disk:pre_install)
post_install+=(10:umorpha-disk:post_install)

umorpha-disk:pre_install() {
	local arg_mountpoint=$1

	mkdir -p "$arg_mountpoint/etc/pacman.d/hooks"
	ln -sT /dev/null "$arg_mountpoint/etc/pacman.d/hooks/90-mkinitcpio-install.hook"
}

umorpha-disk:post_install() {
	local arg_mountpoint=$1

	rm "$arg_mountpoint/etc/pacman.d/hooks/90-mkinitcpio-install.hook"
	rmdir "$arg_mountpoint/etc/pacman.d/hooks" || true

	cat >"$arg_mountpoint/usr/share/mkinitcpio/hook.preset" <<-'EOF'
		#!/hint/bash
		# mkinitcpio preset file for the '%PKGBASE%' package

		#ALL_config="/etc/mkinitcpio.conf"
		ALL_kver="/boot/vmlinuz-%PKGBASE%"
		ALL_microcode=(/boot/*-ucode.img)

		PRESETS=('default' 'fallback')

		#default_config="/etc/mkinitcpio.conf"
		#default_image="/boot/initramfs-%PKGBASE%.img"
		default_uki="/efi/EFI/Linux/parabola-%PKGBASE%.efi"
		#default_options="--splash /usr/share/systemd/bootctl/splash-parabola.bmp"

		#fallback_config="/etc/mkinitcpio.conf"
		#fallback_image="/boot/initramfs-%PKGBASE%-fallback.img"
		fallback_uki="/efi/EFI/Linux/parabola-%PKGBASE%-fallback.efi"
		fallback_options="-S autodetect"
	EOF

	cat >"$arg_mountpoint/usr/lib/initcpio/install/umorpha-overlayfs" <<-'EOF'
		#!/hint/bash
		# Copyright (C) 2023  Umorpha Systems
		# SPDX-License-Identifier: AGPL-3.0-or-later

		build() {
			add_modlule 'overlay'

			add_runscript
		}

		help() {
			cat <<HELPEOF
This hook mounts a read-only root filesystem with a persistent
overlayfs on top of it.

Boot parameters:
 - overlay_root
 - overlay_rootfstype
 - overlay_rootflags
			HELPEOF
		}
	EOF

	cat >"$arg_mountpoint/usr/lib/initcpio/hooks/umorpha-overlayfs" <<-'EOF'
		#!/hint/bash
		# Copyright (C) 2023  Umorpha Systems
		# SPDX-License-Identifier: AGPL-3.0-or-later

		# args: errmsg
		umorpha_emergency_shell() {
		        run_hookfunctions 'run_emergencyhook' 'emergency hook' $EMERGENCYHOOKS
			err "$*"
			echo "You are now being dropped into an emergency shell."
			launch_interactive_shell
			msg "Trying to continue (this will most likely fail) ..."
		}

		# args: /path/to/newroot
		umorpha_mount_handler() {
			local newroot="$1"

			msg ":: mounting '$root'+'$overlay_root' on real root"
			mkdir -p /run/umorpha-root/root /run/umorpha-root/overlay
			local mnt_root=/run/umorpha-root/root
			local mnt_overlay=/run/umorpha-root/overlay
			if ! mount -t "${rootfstype:-auto}" -o "ro${rootflags:+,$rootflags}" "$root" "$mnt_root"; then
				umorpha_emergency_shell "Failed to mount root '$root'"
			fi
			if ! mount -t "${overlay_rootfstype:-auto}" -o "${rwopt:-ro}${overlay_rootflags:+,$overlayrootflags}" "$overlay_root" "$mnt_overlay"; then
				umorpha_emergency_shell "Failed to mount overlay root '$overlay_root'"
			fi
			mkdir -p -- "$mnt_overlay/upperdir" "$mnt_overlay/workdir"
			if ! mount -t overlay -o "lowerdir=${mnt_root},upperdir=${mnt_overlay}/upperdir,workdir=${mnt_overlay}/workdir" umorpha-rootfs "$newroot"; then
				umorpha_emergency_shell "Failed to mount overlayfs lowerdir='${mnt_root}' overlaydir='${mnt_overlay}'"
			fi
		}

		run_hook() {
			export mount_handler='umorpha_mount_handler'
		}
	EOF
}