parch-runit/base/root-overlay/usr/local/bin/metis-chroot

#!/bin/bash

shopt -s extglob

#!/hint/bash

#{{{ message

#set +u +o posix

# shellcheck disable=1091
. /usr/share/makepkg/util.sh

export LANG=C

shopt -s extglob

if [[ -t 2 && "$TERM" != dumb ]]; then
    colorize
else
    # shellcheck disable=2034
    declare -gr ALL_OFF='' BOLD='' BLUE='' GREEN='' RED='' YELLOW=''
fi

stat_busy() {
    local mesg=$1; shift
    # shellcheck disable=2059
    printf "${GREEN}==>${ALL_OFF}${BOLD} ${mesg}...${ALL_OFF}" "$@" >&2
}

stat_done() {
    # shellcheck disable=2059
    printf "${BOLD}done${ALL_OFF}\n" >&2
}

lock_close() {
	local fd=$1
	exec {fd}>&-
}

lock() {
    if ! [[ "/dev/fd/$1" -ef "$2" ]]; then
        mkdir -p -- "$(dirname -- "$2")"
        eval "exec $1>"'"$2"'
    fi
    if ! flock -n "$1"; then
        stat_busy "$3"
        flock "$1"
        stat_done
    fi
}

slock() {
    if ! [[ "/dev/fd/$1" -ef "$2" ]]; then
        mkdir -p -- "$(dirname -- "$2")"
        eval "exec $1>"'"$2"'
    fi
    if ! flock -sn "$1"; then
        stat_busy "$3"
        flock -s "$1"
        stat_done
    fi
}

_setup_workdir=false
setup_workdir() {
    [[ -z ${WORKDIR:-} ]] && WORKDIR=$(mktemp -d --tmpdir "${0##*/}.XXXXXXXXXX")
    _setup_workdir=true
    trap 'trap_abort' INT QUIT TERM HUP
    trap 'trap_exit' EXIT
}

trap_abort() {
    trap - EXIT INT QUIT TERM HUP
    abort
}

trap_exit() {
    local r=$?
    trap - EXIT INT QUIT TERM HUP
    cleanup $r
}

cleanup() {
    if [[ -n ${WORKDIR:-} ]] && $_setup_workdir; then
        rm -rf "$WORKDIR"
    fi
    exit "${1:-0}"
}

abort() {
    error 'Aborting...'
    cleanup 255
}

die() {
    (( $# )) && error "$@"
    cleanup 255
}

#}}}

#!/hint/bash

#{{{ chroot

orig_argv=("$0" "$@")
check_root() {
    local keepenv="$1"

    (( EUID == 0 )) && return
    if type -P sudo >/dev/null; then
        # shellcheck disable=2154
        exec sudo --preserve-env="$keepenv" -- "${orig_argv[@]}"
    else
        # shellcheck disable=2154
        exec su root -c "$(printf ' %q' "${orig_argv[@]}")"
    fi
}

is_btrfs() {
    [[ -e "$1" && "$(stat -f -c %T "$1")" == btrfs ]]
}

is_subvolume() {
    [[ -e "$1" && "$(stat -f -c %T "$1")" == btrfs && "$(stat -c %i "$1")" == 256 ]]
}

# is_same_fs() {
#     [[ "$(stat -c %d "$1")" == "$(stat -c %d "$2")" ]]
# }

subvolume_delete_recursive() {
    local subvol

    is_subvolume "$1" || return 0

    while IFS= read -d $'\0' -r subvol; do
        if ! subvolume_delete_recursive "$subvol"; then
            return 1
        fi
    done < <(find "$1" -mindepth 1 -xdev -depth -inum 256 -print0)
    if ! btrfs subvolume delete "$1" &>/dev/null; then
        error "Unable to delete subvolume %s" "$subvol"
        return 1
    fi

    return 0
}

# }}}

#!/hint/bash

#{{{ mount

ignore_error() {
    "$@" 2>/dev/null
    return 0
}

trap_setup(){
    [[ $(trap -p EXIT) ]] && die 'Error! Attempting to overwrite existing EXIT trap'
    trap "$1" EXIT
}

chroot_mount() {
#     msg2 "mount: [%s]" "$2"
    mount "$@" && CHROOT_ACTIVE_MOUNTS=("$2" "${CHROOT_ACTIVE_MOUNTS[@]}")
}

chroot_add_resolv_conf() {
    local chrootdir=$1 resolv_conf=$1/etc/resolv.conf

    [[ -e /etc/resolv.conf ]] || return 0

    # Handle resolv.conf as a symlink to somewhere else.
    if [[ -L $chrootdir/etc/resolv.conf ]]; then
        # readlink(1) should always give us *something* since we know at this point
        # it's a symlink. For simplicity, ignore the case of nested symlinks.
        resolv_conf=$(readlink "$chrootdir/etc/resolv.conf")
        if [[ $resolv_conf = /* ]]; then
            resolv_conf=$chrootdir$resolv_conf
        else
            resolv_conf=$chrootdir/etc/$resolv_conf
        fi

        # ensure file exists to bind mount over
        if [[ ! -f $resolv_conf ]]; then
            install -Dm644 /dev/null "$resolv_conf" || return 1
        fi
    elif [[ ! -e $chrootdir/etc/resolv.conf ]]; then
        # The chroot might not have a resolv.conf.
        return 0
    fi

    chroot_mount /etc/resolv.conf "$resolv_conf" --bind
}

chroot_mount_conditional() {
    local cond=$1; shift
    if eval "$cond"; then
        chroot_mount "$@"
    fi
}

chroot_setup(){
    local mnt="$1" os="$2" args='-t tmpfs -o nosuid,nodev,mode=0755'
    $os && args='--bind'
    chroot_mount_conditional "! mountpoint -q '$mnt'" "$mnt" "$mnt" --bind &&
    chroot_mount proc "$mnt/proc" -t proc -o nosuid,noexec,nodev &&
    chroot_mount sys "$mnt/sys" -t sysfs -o nosuid,noexec,nodev,ro &&
    ignore_error chroot_mount_conditional "[[ -d '$mnt/sys/firmware/efi/efivars' ]]" \
        efivarfs "$mnt/sys/firmware/efi/efivars" -t efivarfs -o nosuid,noexec,nodev &&
    chroot_mount udev "$mnt/dev" -t devtmpfs -o mode=0755,nosuid &&
    chroot_mount devpts "$mnt/dev/pts" -t devpts -o mode=0620,gid=5,nosuid,noexec &&
    chroot_mount shm "$mnt/dev/shm" -t tmpfs -o mode=1777,nosuid,nodev &&
    chroot_mount /run "$mnt/run" ${args} &&
    chroot_mount tmp "$mnt/tmp" -t tmpfs -o mode=1777,strictatime,nodev,nosuid
}

chroot_api_mount() {
    CHROOT_ACTIVE_MOUNTS=()
    trap_setup chroot_api_umount
    chroot_setup "$1" false
}

chroot_api_umount() {
    if (( ${#CHROOT_ACTIVE_MOUNTS[@]} )); then
#         msg2 "umount: [%s]" "${CHROOT_ACTIVE_MOUNTS[@]}"
        umount "${CHROOT_ACTIVE_MOUNTS[@]}"
    fi
    unset CHROOT_ACTIVE_MOUNTS
}

#}}}



usage() {
    printf 'usage: %s chroot-dir [command]\n' "${0##*/}"
    printf '    -h             Print this help message\n'
    printf '\n'
    printf "    If 'command' is unspecified, %s will launch /bin/sh.\n" "${0##*/}"
    printf '\n'
    printf '\n'
    exit "$1"
}

opts=':h'

while getopts ${opts} arg; do
    case "${arg}" in
        h|?) usage 0 ;;
    esac
done
shift $(( OPTIND - 1 ))

check_root

chrootdir=$1
shift

[[ -d ${chrootdir} ]] || die "Can't create chroot on non-directory %s" "${chrootdir}"

chroot_api_mount "${chrootdir}" || die "failed to setup API filesystems in chroot %s" "${chrootdir}"
chroot_add_resolv_conf "${chrootdir}"

SHELL=/bin/sh unshare --fork --pid chroot "${chrootdir}" "$@"