arkdep/arkdep-build

#!/usr/bin/env bash

#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.

# Print manual if no parameters provided or invalid amount of parameters is provided
if [[ ! -n $1 || -n $2 ]]; then
	cat <<- END
	Usage: arkdep-build [variant]
	Variants:
	  archlinux		Plain Arch Linux TTY image
	  arkanelinux		Arkane Linux GNOME image

	Variants are loaded based on their directory names, the ones listed here
	 are included by default.

	Variables:
	  ARKDEP_NO_TAR			Do not create a compressed tarball, only create the images
	  ARKDEP_CUSTOM_NAME		Define a custom image name
	  ARKDEP_OUTPUT_TARGET		Overwrite location to which images will be written
	  ARKDEP_CONFIGS		Define directory in which build will search for configuration files
	  ARKDEP_NO_CLEANUP		Do not remove the temporary rootfs upon error or exit
	END
	exit 0
fi

## Common functions
#
# Cleanup and quit if error
cleanup_and_quit () {

	# If any paramters are passed we will assume it to be an error
	[[ -n $1 ]] && printf "\e[1;31m<#>\e[0m $*\e[0m\n" >&2

	if [[ $ARKDEP_NO_CLEANUP -eq 1 ]]; then
		printf 'Cleanup disabled, not running cleanup\n'
		exit 1
	fi

	umount $workdir

	btrfs property set -ts $workdir ro false
	btrfs property set -ts $workdir/etc ro false
	btrfs property set -ts $workdir/var ro false

	# Remove temporary btrfs volumes
	rm -rf $workdir/etc \
		$workdir/var \
		$workdir

	# Quit program if argument provided to function
	if [[ -n $1 ]]; then
		exit 1
	fi

	# Otherwise just quit, there is no error
	exit 0

}

## Set common variables
#
declare -r workdir='/var/tmp/rootfs'
declare -r variant="$1"

if [[ -v ARKDEP_CONFIGS ]]; then
	declare -r configsdir="$ARKDEP_CONFIGS"
else
	declare -r configsdir="$(readlink -m ./arkdep-build.d/)"
fi

declare -r variantdir="$configsdir/$variant"
declare -r type="$(cat $(readlink -m $variantdir/type) 2> /dev/null || cleanup_and_quit 'Failed to get build type')"

if [[ -v ARKDEP_OUTPUT_TARGET ]]; then
	declare -r output_target="$ARKDEP_OUTPUT_TARGET"
else
	declare -r output_target="$(pwd)/target/"
fi

## Set common functions
#
# Generate a 42 character long random string, used for generating psuedo-random image names
# Unless overwritten with $ARKDEP_CUSTOM_NAME
gen_random_string () {

	if [[ -v ARKDEP_CUSTOM_NAME ]]; then
		random=$ARKDEP_CUSTOM_NAME
	else
		random=$(openssl rand -hex 100 | head -c 42)
	fi

	printf "${random}\n"

}

## Error checking
#
# Quit if not root
if [[ ! $EUID -eq 0 ]]; then
	printf '\e[1;31m<#>\e[0m\e[1m This program has to be run as root\n\e[0m' &&
	exit 1
fi

# Check if all dependencies are installed, quit if not
for prog in btrfs pacstrap; do
	if ! command -v $prog > /dev/null; then
		printf "\e[1;31m<#>\e[0m\e[1m Failed to locate $prog, ensure it is installed\e[0m\n"
		exit 1
	fi
done

# Check if requested variant exists
if [[ ! -d $variantdir ]]; then
	printf '\e[1;31m<#>\e[0m\e[1m The requested variant does not exist\e[0m\n' &&
	exit 1
fi

## Variants
#
# Build archlinux type image
if [[ $type == 'archlinux' ]]; then

	# Ensure bootstrap.list exists, if not error and quit
	if [[ ! -e $variantdir/bootstrap.list ]]; then
		printf "\e[1;31m<#>\e[0m\e[1m The required file 'bootstrap.list' is not preset in $(readlink -m $variantdir)\e[0m\n" &&
		exit 1
	fi

	printf '\e[1;34m-->\e[0m\e[1m Started Arch linux image build\e[0m\n'

	# Create temporary Btrfs subvolume
	printf "\e[1;34m-->\e[0m\e[1m Creating temporary Btrfs subvolumes at $(readlink -m $workdir)\e[0m\n"
	btrfs subvolume create $workdir || cleanup_and_quit "Failed to create btrfs subvolume $(readlink -m $workdir)"
	btrfs subvolume create $workdir/etc || cleanup_and_quit "Failed to create btrfs subvolume $(readlink -m $workdir/etc)"
	btrfs subvolume create $workdir/var || cleanup_and_quit "Failed to create btrfs subvolume $(readlink -m $workdir/var)"

	printf "\e[1;34m-->\e[0m\e[1m Creating bind mount at $(readlink -m $workdir)\e[0m\n"
	mount --bind $workdir $workdir

	# Read base package list and install base system
	readarray bootstrap_packages < $variantdir/bootstrap.list
	printf '\e[1;34m-->\e[0m\e[1m Installing base packages\e[0m\n'
	pacstrap -c $workdir ${bootstrap_packages[*]} || cleanup_and_quit 'Failed to install secondary package list'

	# If overlay directory exists in variant copy it's contents to the temporary subvolume
	if [[ -d $variantdir/overlay ]]; then
		printf '\e[1;34m-->\e[0m\e[1m Copying overlay to root\e[0m\n'
		cp -rv $variantdir/overlay/* $workdir/
	fi

	# Run post-bootstrap script if exists
	if [[ -f $variantdir/extensions/post-bootstrap.sh ]]; then
		printf '\e[1;34m-->\e[0m\e[1m Running post-bootstrap extension\e[0m\n'
		(source $variantdir/extensions/post-bootstrap.sh)
	fi

	# Read package list and install secondary system components, skip if not used
	if [[ -e $variantdir/package.list ]]; then
		printf '\e[1;34m-->\e[0m\e[1m Installing secondary packages\e[0m\n'
		readarray packages < $variantdir/package.list
		arch-chroot $workdir pacman -S --noconfirm ${packages[*]} || cleanup_and_quit 'Failed to install base packages'
	fi

	# Run post-install script if exists
	if [[ -f $variantdir/extensions/post-install.sh ]]; then
		printf '\e[1;34m-->\e[0m\e[1m Running post-install extension\e[0m\n'
		(source $variantdir/extensions/post-install.sh)
	fi

	# Clear pacman cache
	printf '\e[1;34m-->\e[0m\e[1m Clearing pacman cache\e[0m\n'
	arch-chroot $workdir pacman -Scc <<< Y <<< Y
	# Insert a new line to clean, the previous command fails to do so
	printf '\n'

	# Remove subvolumes created by systemd
	[[ -d $workdir/var/lib/portables ]] &&
		printf '\e[1;34m-->\e[0m\e[1m Removing systemd subvolume var/lib/portables\e[0m\n'
		btrfs subvolume delete $workdir/var/lib/portables
	[[ -d $workdir/var/lib/machines ]] &&
		printf '\e[1;34m-->\e[0m\e[1m Removing systemd subvolume var/lib/machines\e[0m\n'
		btrfs subvolume delete $workdir/var/lib/machines

	# Make /usr/local symlink in var
	printf '\e[1;34m-->\e[0m\e[1m Moving dirs to var and creating symlinks\e[0m\n'
	mv $workdir/usr/local $workdir/var/usrlocal || cleanup_and_quit 'Failed to move usr/local to var/usrlocal'
	ln -sv ../var/usrlocal $workdir/usr/local || cleanup_and_quit 'Failed to create usrlocal symlink'

	# locale symlink
	mv $workdir/usr/lib/locale $workdir/var/usrliblocale || cleanup_and_quit 'Failed to move usr/local to var/usrlocal'
	ln -sv ../../../var/usrliblocale $workdir/usr/lib/locale || cleanup_and_quit 'Failed to create usrlocal symlink'

	# roothome symlink
	mv $workdir/root $workdir/var/roothome || cleanup_and_quit 'Failed to move root to var/roothome'
	ln -sv var/roothome $workdir/root || cleanup_and_quit 'Failed to create roothome symlink'

	# Opt symlink
	mv $workdir/opt $workdir/var/opt || cleanup_and_quit 'Failed to move opt to var/opt'
	ln -sv var/opt $workdir/opt || cleanup_and_quit 'Failed to create opt symlink'

	# srv symlink
	mv $workdir/srv $workdir/var/srv || cleanup_and_quit 'Failed to move srv to var/srv'
	ln -sv var/srv $workdir/srv || cleanup_and_quit 'Failed to create srv symlink'

	# mnt symlink
	mv $workdir/mnt $workdir/var/mnt || cleanup_and_quit 'Failed to move mnt to var/mnt'
	ln -sv var/mnt $workdir/mnt || cleanup_and_quit 'Failed to create mnt symlink'

	printf '\e[1;34m-->\e[0m\e[1m Moving passwd, shadow and group files to usr/lib\e[0m\n'

	# Create second passwd, group and shadow file in usr/lib and configure
	for file in passwd group shadow; do
		grep -v "^root:" $workdir/etc/$file > $workdir/usr/lib/$file
	done

	# Remove all users except for root, is typically overwritten by user overlay but
	# may be used during os installation as a template
	for file in passwd group shadow; do
		grep "^root:" $workdir/etc/$file > $workdir/etc/$file-tmp
		mv $workdir/etc/$file-tmp $workdir/etc/$file
	done

	# Ensure passwd/group/shadow permissions are set properly
	chmod 600 $workdir/etc/shadow $workdir/usr/lib/shadow
	chmod 644 $workdir/etc/{passwd,group} $workdir/usr/lib/{passwd,group}

	#
	# nss-switch.conf is added using the overlay
	#

	# Remove passwd/group/shadow backup files
	rm $workdir/etc/{passwd-,shadow-,group-}

	printf '\e[1;34m-->\e[0m\e[1m Moving CPU microcode to usr/lib\e[0m\n'
	# Move CPU firmware to /usr/lib if present
	mv $workdir/boot/*-ucode.img $workdir/usr/lib/

	# Make subvolume read-only
	printf '\e[1;34m-->\e[0m\e[1m Adding read-only property to subvolumes\e[0m\n'
	btrfs property set -ts $workdir ro true || cleanup_and_quit 'Failed to set root to read-only'
	btrfs property set -ts $workdir/etc ro true || cleanup_and_quit 'Failed to set etc to read-only'
	btrfs property set -ts $workdir/var ro true || cleanup_and_quit 'Failed to set var to read-only'

	# Generate random name for new image
	printf '\e[1;34m-->\e[0m\e[1m Generating psuedo-random image name\e[0m\n'
	declare -r image_name=$(gen_random_string)
	printf "$image_name\n"

	# Create dir for storing the images
	mkdir -vp $(readlink -m $output_target/$image_name)

	# Write subvolume to image
	printf '\e[1;34m-->\e[0m\e[1m Creating images\e[0m\n'
	btrfs send -f $output_target/$image_name/$image_name-rootfs.img $workdir
	btrfs send -f $output_target/$image_name/$image_name-etc.img $workdir/etc
	btrfs send -f $output_target/$image_name/$image_name-var.img $workdir/var

	if [[ ! -v ARKDEP_NO_TAR ]]; then
		printf '\e[1;34m-->\e[0m\e[1m Compressing images\e[0m\n'
		tar -cv -I 'zstd -12 -T0 ' -f $output_target/$image_name.tar.zst -C $output_target/$image_name .
	fi

	cleanup_and_quit

fi