Mini Shell

#!/bin/bash
# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
# ex: ts=8 sw=4 sts=4 et filetype=sh
# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# Copyright © 2013 Harald Hoyer
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# systemd is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with systemd; If not, see <http://www.gnu.org/licenses/>.

SKIP_REMAINING=77

usage()
{
    echo "Usage:"
    echo "        $0 add KERNEL-VERSION KERNEL-IMAGE"
    echo "        $0 remove KERNEL-VERSION"
}

dropindirs_sort()
{
    local suffix=$1; shift
    local -a files
    local f d i

    readarray -t files <<<"$(
        for d in "$@"; do
            for i in "$d/"*"$suffix"; do
                if [[ -e "$i" ]]; then
                    echo "${i##*/}"
                fi
            done
        done | sort -Vu
    )"

    for f in "${files[@]}"; do
        for d in "$@"; do
            if [[ -e "$d/$f" ]]; then
                echo "$d/$f"
                continue 2
            fi
        done
    done
}

export LC_COLLATE=C

for i in "$@"; do
    if [ "$i" == "--help" -o "$i" == "-h" ]; then
        usage
        exit 0
    fi
done

if [[ "${0##*/}" == 'installkernel' ]]; then
    COMMAND='add'
else
    COMMAND="$1"
    shift
fi

KERNEL_VERSION="$1"
KERNEL_IMAGE="$2"

if [[ -f /etc/machine-id ]]; then
    read MACHINE_ID < /etc/machine-id
fi

if [[ ! $COMMAND ]] || [[ ! $KERNEL_VERSION ]]; then
    echo "Not enough arguments" >&2
    exit 1
fi

if ! [[ $MACHINE_ID ]]; then
    BOOT_DIR_ABS=$(mktemp -d /tmp/kernel-install.XXXXX) || exit 1
    trap "rm -rf '$BOOT_DIR_ABS'" EXIT INT QUIT PIPE
elif [[ -d /efi/loader/entries ]] || [[ -d /efi/$MACHINE_ID ]]; then
    BOOT_DIR_ABS="/efi/$MACHINE_ID/$KERNEL_VERSION"
elif [[ -d /boot/loader/entries ]] || [[ -d /boot/$MACHINE_ID ]]; then
    BOOT_DIR_ABS="/boot/$MACHINE_ID/$KERNEL_VERSION"
elif [[ -d /boot/efi/loader/entries ]] || [[ -d /boot/efi/$MACHINE_ID ]]; then
    BOOT_DIR_ABS="/boot/efi/$MACHINE_ID/$KERNEL_VERSION"
elif mountpoint -q /efi; then
    BOOT_DIR_ABS="/efi/$MACHINE_ID/$KERNEL_VERSION"
elif mountpoint -q /boot/efi; then
    BOOT_DIR_ABS="/boot/efi/$MACHINE_ID/$KERNEL_VERSION"
else
    BOOT_DIR_ABS="/boot/$MACHINE_ID/$KERNEL_VERSION"
fi

export KERNEL_INSTALL_MACHINE_ID=$MACHINE_ID

ret=0

readarray -t PLUGINS <<<"$(
    dropindirs_sort ".install" \
        "/etc/kernel/install.d" \
        "/usr/lib/kernel/install.d"
)"

case $COMMAND in
    add)
        if [[ ! "$KERNEL_IMAGE" ]]; then
            echo "Command 'add' requires an argument" >&2
            exit 1
        fi

        mkdir -p "$BOOT_DIR_ABS" || {
            echo "Could not create boot directory '$BOOT_DIR_ABS'." >&2
            exit 1
        }

        for f in "${PLUGINS[@]}"; do
            if [[ -x $f ]]; then
                "$f" add "$KERNEL_VERSION" "$BOOT_DIR_ABS" "$KERNEL_IMAGE"
                x=$?
                if [[ $x == $SKIP_REMAINING ]]; then
                    ret=0
                    break
                fi
                ((ret+=$x))
            fi
        done

        if ! [[ $MACHINE_ID ]] && ! rmdir "$BOOT_DIR_ABS"; then
            echo "Warning: In kernel-install plugins, requiring BOOT_DIR_ABS to be preset is deprecated." >&2
            echo "         All plugins should not put anything in BOOT_DIR_ABS if the environment" >&2
            echo "         variable KERNEL_INSTALL_MACHINE_ID is empty." >&2
            rm -rf "$BOOT_DIR_ABS"
            ((ret+=$?))
        fi
        ;;

    remove)
        for f in "${PLUGINS[@]}"; do
            if [[ -x $f ]]; then
                "$f" remove "$KERNEL_VERSION" "$BOOT_DIR_ABS"
                x=$?
                if [[ $x == $SKIP_REMAINING ]]; then
                    ret=0
                    break
                fi
                ((ret+=$x))
            fi
        done

        rm -rf "$BOOT_DIR_ABS"
        ((ret+=$?))
        ;;

    *)
        echo "Unknown command '$COMMAND'" >&2
        exit 1
        ;;
esac

exit $ret