update-kernel.in

#!/bin/sh -e

# update-kernel
#
# Kernel and firmware update script for Alpine installations set up
# with setup-bootable
#
# Copyright (c) 2014 Timo Teräs
# Copyright (c) 2014 Kaarle Ritvanen


SCRIPT=update-kernel
VIRTUAL=.tmp-$SCRIPT

BUILDDIR=
FLAVOR=
MNTDIR=
PACKAGES=
SIGNALS="HUP INT TERM"
TMPDIR=
features=

OPTS=$(getopt -l build-dir:,flavor:,feature:,package: -n $SCRIPT -o b:f:F:p: \
    -- "$@")
eval set -- "$OPTS"
while :; do
    case "$1" in
	-b|--build-dir)
	    BUILDDIR=$2
	    ;;
	-f|--flavor)
	    FLAVOR=$2
	    ;;
	-F|--feature)
	    features="$features $2"
	    ;;
	-p|--package)
	    PACKAGES="$PACKAGES $2"
	    ;;
	--)
	    break
	    ;;
    esac
    shift 2
done

DESTDIR=$2


error() {
    echo "$1" >&2
    exit 1
}

[ "$BUILDDIR" -a "$FLAVOR" ] && \
    error "Cannot specify both build directory and flavor"

if [ -z "$DESTDIR" ]; then
    [ "$FLAVOR" ] && error "Cannot specify flavor when updating the current kernel"

    while read MOUNT; do
	set -- $MOUNT
	[ $2 = /.modloop ] || continue
	DESTDIR=$(dirname $(losetup $1 | cut -d " " -f 3))
	MNTDIR=$(dirname "$DESTDIR")
	break
    done < /proc/mounts

    [ "$MNTDIR" ] || error "Module loopback device not mounted"
fi

remount() {
    mount $1 -o remount "$MNTDIR"
}


ignore_sigs() {
    trap "" $SIGNALS
}

clean_up() {
    set +e
    ignore_sigs

    apk del -q $VIRTUAL
    rm -fr "$TMPDIR"
}

trap clean_up EXIT $SIGNALS


apk add -qU -t $VIRTUAL mkinitfs squashfs-tools

if [ -z "$features" ]; then
    . /etc/mkinitfs/mkinitfs.conf
fi

if [ -z "$FLAVOR" ]; then
    FLAVOR=$(uname -r | cut -d - -f 3-)
    [ "$FLAVOR" ] || FLAVOR=vanilla
fi

TMPDIR=$(mktemp -dt $SCRIPT.XXXXXX)
ROOT=$TMPDIR/root
BOOT=$ROOT/boot

_apk() {
    local cmd=$1
    shift
    apk $cmd -p "$ROOT" --keys-dir /etc/apk/keys \
	--repositories-file /etc/apk/repositories $*
}

add_pkgs() {
    _apk add -q --no-scripts $*
}

extra_pkgs() {
    local res=$(_apk search -x $1)
    if [ "$res" ]; then
	add_pkgs $*
    fi
}

add_pkgs -U --initdb alpine-base $PACKAGES
if [ "$BUILDDIR" ]; then
    mkdir -p "$BOOT"
    make -C "$BUILDDIR" firmware_install install modules_install \
	INSTALL_MOD_PATH="$ROOT" INSTALL_PATH="$BOOT"
else
    add_pkgs "linux-$FLAVOR" linux-firmware
    if [ -z "$PACKAGES" ]; then
	extra_pkgs "dahdi-linux-$FLAVOR" dahdi-linux
	extra_pkgs "xtables-addons-$FLAVOR"
    fi
fi


KVER_FLAVOR=
[ "$FLAVOR" = vanilla ] || KVER_FLAVOR=-$FLAVOR
KVER=$(basename $(ls -d "$ROOT"/lib/modules/*"$KVER_FLAVOR"))
depmod -b "$ROOT" "$KVER"


STAGING=$TMPDIR/boot
MODLOOP=$TMPDIR/modloop
MODIMG=$FLAVOR.modloop.squashfs

mkdir "$MODLOOP" "$STAGING"
cp -a "$ROOT/lib/modules" "$MODLOOP"
cp -a "$ROOT/lib/firmware" "$MODLOOP/modules"
mksquashfs "$MODLOOP" "$STAGING/$MODIMG" -comp xz

mkinitfs -q -b "$ROOT" -F "$features base squashfs" -o "$STAGING/$FLAVOR.gz" \
    "$KVER"
cp "$BOOT/vmlinuz$KVER_FLAVOR" "$STAGING/$FLAVOR"


if [ "$MNTDIR" ]; then
    ignore_sigs
    remount -w
    rm -f "$DESTDIR/$MODIMG"
fi

mv "$STAGING"/* "$DESTDIR"

if [ "$MNTDIR" ]; then
    set +e
    sync
    remount -r
fi

exit 0