tinyarch_script

#!/usr/bin/zsh

setopt ERR_EXIT

_MOUNTS=()

PKGIGNORE=(
    'jfsutils'
    'lvm2'
    'cryptsetup'
    'groff'
    'man-db'
    'man-pages'
    'mdadm'
    'pciutils'
    'pcmciautils'
    'reiserfsprogs'
    's-nail'
    'xfsprogs'
)

CONTAINER_PACKAGES=(
    # Required for the initramfs
    'arch-install-scripts'      # pacstrap
    'bzip2'
    'dhcpcd'
    'findutils'
    'gzip'
    'linux'
    'pacman'
    'python2'
    'syslinux'                  # boot loader
    'tar'
    'util-linux'                # we need setsid

    # Required by the container to generate the iso + initramfs
    'binutils'          # mkinitcpio strip hook needes file
    'coreutils'         # basic tools
    'systemd'           # init system for the container
    'filesystem'        # base file system
    'xorriso'           # creates the el torito iso
    'zsh'               # this script runs only on zsh
    'file'              # mkinitcpio strip hook needes file
    # 'virtualbox-guest-modules'
)

msg() {
    # bold and green
    printf "$(tput bold)$(tput setaf 2) $1$(tput sgr0)\n" >&1
}

info() {
    # bold and blue
    printf "$(tput bold)$(tput setaf 4) -> $1$(tput sgr0)\n" >&1
}

error () {
    # bold and red
    printf "$(tput bold)$(tput setaf 1) ERROR: $1$(tput sgr0)\n" >&1
}

die() {
    error "$@"
    exit 1
}

usage() {
    die "$0 [container|iso] {additional packages to install in the container}"
}

container() {
    # creates the container that will generate the image
    msg "Setting up the container"

    info "filesystem directories and mount points"
    filesystem
    mountpoints

    packages="${@[*]}"
    info "pacman [installing ${#@}: $packages]"
    packages $@
    info "pacman done"
}

build() {
    # workhorse, this will generate the image
    msg "Starting the build"

    info "filesystem directories"
    filesystem

    info "installing the kernel"
    kernel

    info "installing syslinux bootloader"
    bootloader

    info "generating the iso"
    image
}

_mount() {
    # Utility for keeping track of mounted filesystems
    [ ! -z ${_MOUNTS[(r)$2]} ] && return
    mount "$@"
    _MOUNTS=("$2" "${_MOUNTS[@]}")
}

_umount() {
    # Utility to automatically umount filesystem
    [ -z "$_MOUNTS[*]" ] && return
    umount "${_MOUNTS[@]}"
    _MOUNTS=()
}

cleanup() {
    msg "Cleaning up"
    _umount
    rm -rf "${WORKDIR}"
}

filesystem() {
    mkdir -m 0755 -p "${WORKDIR}"/var/{cache/pacman/pkg,lib/pacman,log} "${WORKDIR}"/{dev,run,etc,boot,mnt,media,home}
    mkdir -m 1777 -p "${WORKDIR}"/tmp
    mkdir -m 0555 -p "${WORKDIR}"/{sys,proc}
}

mountpoints() {
    _mount proc "${WORKDIR}/proc" -t proc -o nosuid,noexec,nodev
    _mount sys "${WORKDIR}/sys" -t sysfs -o nosuid,noexec,nodev,ro
    _mount udev "${WORKDIR}/dev" -t devtmpfs -o mode=0755,nosuid
    _mount devpts "${WORKDIR}/dev/pts" -t devpts -o mode=0620,gid=5,nosuid,noexec
    _mount shm "${WORKDIR}/dev/shm" -t tmpfs -o mode=1777,nosuid,nodev
    _mount run "${WORKDIR}/run" -t tmpfs -o nosuid,nodev,mode=0755
    _mount tmp "${WORKDIR}/tmp" -t tmpfs -o mode=1777,strictatime,nodev,nosuid
}

packages() {
    local pkgignore files file packages ignore
    packages=$@

    for ignore in ${PKGIGNORE:|packages}; do
        pkgignore=("${pkgignore[@]}" "--ignore" ${ignore})
    done

    (pacman --root "${WORKDIR}" --noconfirm --noprogressbar -Sy $@ $pkgignore || die "pacman failed" ) |& \
        grep -E '^(checking|loading|installing|warning: skip)'

    files=(
        /etc/mkinitcpio-tinyarch.conf
        /usr/share/tinyarch/tinyarch.cfg
        /usr/share/tinyarch/init
        /usr/lib/initcpio/install/tinyarch
        /usr/lib/initcpio/install/tinyarch_qemu
    )
    for file in $files; do
        [ ! -f "${WORKDIR}/$file" ] && install -D -m644 $file "${WORKDIR}/$file"
    done

    if [[ ! -f "${WORKDIR}/usr/bin/tinyarch" ]]; then
        install -D -m755 /usr/bin/tinyarch "${WORKDIR}/usr/bin/tinyarch"
    fi

    if [[ -d /etc/pacman.d/gnupg && ! -d "${WORKDIR}/etc/pacman.d/gnupg" ]]; then
        cp -r /etc/pacman.d/gnupg "${WORKDIR}/etc/pacman.d/"
    fi

    if [[ -d /etc/pacman.d/mirrorlist && ! -d "${WORKDIR}/etc/pacman.d/mirrorlist" ]]; then
        cp -r /etc/pacman.d/mirrorlist "${WORKDIR}/etc/pacman.d/"
    fi
}

kernel(){
    install -m644 /boot/vmlinuz-linux "${BOOT}"/vmlinuz-linux
    mkinitcpio -c /etc/mkinitcpio-tinyarch.conf -k $(uname -r) -g "${BOOT}"/initrd.img
}

bootloader() {
    install -D -m644 /usr/share/tinyarch/tinyarch.cfg "${SYSLINUX}"/syslinux.cfg

    files=(
        /usr/lib/syslinux/bios/isolinux.bin
        /usr/lib/syslinux/bios/ldlinux.c32
        /usr/lib/syslinux/bios/boot.cat             # TODO: mkisofs creates the catalog with the flag `-c` does xorriso have a equivalent?
    )

    for file in $files; do
        [ -f $file ] && install -D -m644 $file "${SYSLINUX}"/$(basename $file)
    done
}

image() {
    xorriso                                                 \
        -as mkisofs                                         \
        -iso-level 3                                        \
        -joliet                                             \
        -rock                                               \
        -max-iso9660-filenames                              \
        -relaxed-filenames                                  \
        -allow-leading-dots                                 \
        -allow-lowercase                                    \
        -allow-multidot                                     \
        -boot-info-table                                    \
        -boot-load-size 4                                   \
        -eltorito-boot boot/syslinux/isolinux.bin           \
        -eltorito-catalog boot/syslinux/boot.cat            \
        -isohybrid-mbr /usr/lib/syslinux/bios/isohdpfx.bin  \
        -no-emul-boot                                       \
        -omit-period                                        \
        -omit-version-number                                \
        -preparer "prepared by tinyarch"                    \
        --sort-weight 1 boot/syslinux/isolinux.bin          \
        -volid "TINYARCH"                                   \
        -output "tinyarch.iso"                              \
        "${WORKDIR}/" &> /dev/null
}

(( $# )) || usage

trap 'cleanup' EXIT

if [ $1 = 'container' ]; then
    WORKDIR=$(mktemp -d --suffix 'tinyarch.container')
    BOOT="$WORKDIR/boot"
    SYSLINUX="$BOOT/syslinux"

    # install packages and config files
    all_packages=($CONTAINER_PACKAGES ${@:2})
    container $all_packages

    # unmount filesystems (seems to annoy systemd-nspawn)
    _umount

    # run the iso builder inside the container
    systemd-nspawn -D "$WORKDIR" /usr/bin/tinyarch iso

    # copy the iso before the workdir is deleted
    cp "${WORKDIR}"/tinyarch.iso ./tinyarch.iso
elif [ $1 = 'iso' ]; then
    WORKDIR=$(mktemp -d --suffix 'tinyarch.iso')
    BOOT="$WORKDIR/boot"
    SYSLINUX="$BOOT/syslinux"

    build
else
    usage
fi