Mini Shell

#!/usr/bin/sh
# -*- 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-or-later
#
# This file is part of systemd.
#
# 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 <https://www.gnu.org/licenses/>.

set -e

COMMAND="${1:?}"
KERNEL_VERSION="${2:?}"
ENTRY_DIR_ABS="${3:?}"
KERNEL_IMAGE="$4"
INITRD_OPTIONS_SHIFT=4

[ "$KERNEL_INSTALL_LAYOUT" = "bls" ] || exit 0

MACHINE_ID="$KERNEL_INSTALL_MACHINE_ID"
ENTRY_TOKEN="$KERNEL_INSTALL_ENTRY_TOKEN"
BOOT_ROOT="$KERNEL_INSTALL_BOOT_ROOT"

BOOT_MNT="$(stat -c %m "$BOOT_ROOT")"
if [ "$BOOT_MNT" = '/' ]; then
    ENTRY_DIR="$ENTRY_DIR_ABS"
else
    ENTRY_DIR="${ENTRY_DIR_ABS#"$BOOT_MNT"}"
fi

case "$COMMAND" in
    remove)
        [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && \
            echo "Removing $BOOT_ROOT/loader/entries/$ENTRY_TOKEN-$KERNEL_VERSION*.conf"
        exec rm -f \
            "$BOOT_ROOT/loader/entries/$ENTRY_TOKEN-$KERNEL_VERSION.conf" \
            "$BOOT_ROOT/loader/entries/$ENTRY_TOKEN-$KERNEL_VERSION+"*".conf"
        ;;
    add)
        ;;
    *)
        exit 0
        ;;
esac

if [ -f /etc/os-release ]; then
    # shellcheck source=/dev/null
    . /etc/os-release
elif [ -f /usr/lib/os-release ]; then
    # shellcheck source=/dev/null
    . /usr/lib/os-release
fi

[ -n "$PRETTY_NAME" ] || PRETTY_NAME="Linux $KERNEL_VERSION"

SORT_KEY="$IMAGE_ID"
[ -z "$SORT_KEY" ] && SORT_KEY="$ID"

if [ -n "$KERNEL_INSTALL_CONF_ROOT" ]; then
    if [ -f "$KERNEL_INSTALL_CONF_ROOT/cmdline" ]; then
        BOOT_OPTIONS="$(tr -s "$IFS" ' ' <"$KERNEL_INSTALL_CONF_ROOT/cmdline")"
    fi
elif [ -f /etc/kernel/cmdline ]; then
    BOOT_OPTIONS="$(tr -s "$IFS" ' ' </etc/kernel/cmdline)"
elif [ -f /usr/lib/kernel/cmdline ]; then
    BOOT_OPTIONS="$(tr -s "$IFS" ' ' </usr/lib/kernel/cmdline)"
else
    BOOT_OPTIONS="$(tr -s "$IFS" '\n' </proc/cmdline | grep -ve '^BOOT_IMAGE=' -e '^initrd=' | tr '\n' ' ')"
fi

BOOT_OPTIONS="${BOOT_OPTIONS% }"

# If the boot entries are named after the machine ID, then suffix the kernel
# command line with the machine ID we use, so that the machine ID remains
# stable, even during factory reset, in the initrd (where the system's machine
# ID is not directly accessible yet), and if the root file system is volatile.
if [ "$ENTRY_TOKEN" = "$MACHINE_ID" ] && ! echo "$BOOT_OPTIONS" | grep -q "systemd.machine_id="; then
    BOOT_OPTIONS="$BOOT_OPTIONS systemd.machine_id=$MACHINE_ID"
fi

TRIES_FILE="${KERNEL_INSTALL_CONF_ROOT:-/etc/kernel}/tries"

if [ -f "$TRIES_FILE" ]; then
    read -r TRIES <"$TRIES_FILE"
    if ! echo "$TRIES" | grep -q '^[0-9][0-9]*$'; then
        echo "$TRIES_FILE does not contain an integer." >&2
        exit 1
    fi
    LOADER_ENTRY="$BOOT_ROOT/loader/entries/$ENTRY_TOKEN-$KERNEL_VERSION+$TRIES.conf"
else
    LOADER_ENTRY="$BOOT_ROOT/loader/entries/$ENTRY_TOKEN-$KERNEL_VERSION.conf"
fi

if ! [ -d "$ENTRY_DIR_ABS" ]; then
    echo "Error: entry directory '$ENTRY_DIR_ABS' does not exist" >&2
    exit 1
fi

install -m 0644 "$KERNEL_IMAGE" "$ENTRY_DIR_ABS/linux" || {
    echo "Error: could not copy '$KERNEL_IMAGE' to '$ENTRY_DIR_ABS/linux'." >&2
    exit 1
}
chown root:root "$ENTRY_DIR_ABS/linux" || :

shift "$INITRD_OPTIONS_SHIFT"
# All files listed as arguments, and staged files starting with "initrd" are installed as initrds.
for initrd in "$@" "${KERNEL_INSTALL_STAGING_AREA}"/initrd*; do
    [ -f "$initrd" ] || {
        [ "$initrd" = "${KERNEL_INSTALL_STAGING_AREA}/initrd*" ] && continue
        echo "Error: initrd '$initrd' not a file." >&2
        exit 1
    }

    initrd_basename="${initrd##*/}"
    [ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Installing $ENTRY_DIR_ABS/$initrd_basename"
    install -m 0644 "$initrd" "$ENTRY_DIR_ABS/$initrd_basename" || {
        echo "Error: could not copy '$initrd' to '$ENTRY_DIR_ABS/$initrd_basename'." >&2
        exit 1
    }
    chown root:root "$ENTRY_DIR_ABS/$initrd_basename" || :
done

mkdir -p "${LOADER_ENTRY%/*}" || {
    echo "Error: could not create loader entry directory '${LOADER_ENTRY%/*}'." >&2
    exit 1
}

[ "$KERNEL_INSTALL_VERBOSE" -gt 0 ] && echo "Creating $LOADER_ENTRY"
{
    echo "title      $PRETTY_NAME"
    echo "version    $KERNEL_VERSION"
    if [ "$ENTRY_TOKEN" = "$MACHINE_ID" ]; then
        # See similar logic above for the systemd.machine_id= kernel command line option
        echo "machine-id $MACHINE_ID"
    fi
    [ -n "$SORT_KEY" ] && echo "sort-key   $SORT_KEY"
    echo "options    $BOOT_OPTIONS"
    echo "linux      $ENTRY_DIR/linux"

    have_initrd=
    for initrd in "${@}" "${KERNEL_INSTALL_STAGING_AREA}"/initrd*; do
        [ -f "$initrd" ] || continue
        echo "initrd     $ENTRY_DIR/${initrd##*/}"
        have_initrd=yes
    done

    # Try "initrd", generated by dracut in its kernel-install hook, if no initrds were supplied
    [ -z "$have_initrd" ] && [ -f "$ENTRY_DIR_ABS/initrd" ] && echo "initrd     $ENTRY_DIR/initrd"
    :
} >"$LOADER_ENTRY" || {
    echo "Error: could not create loader entry '$LOADER_ENTRY'." >&2
    exit 1
}
exit 0