update-grub

#!/bin/sh
# SPDX-License-Identifier: MIT

set -e

[ -e /etc/default/update-grub ] && . /etc/default/update-grub

if [ -e "$(dirname "$0")"/functions.sh ]; then
    . "$(dirname "$0")"/functions.sh
else
    . /usr/share/asahi-scripts/functions.sh
fi

: ${BOOT_PART:="/boot"}
: ${EFI_PART:=}
: ${GRUB_DIR:="$BOOT_PART/grub"}
: ${CONFIG:="$GRUB_DIR/grub.cfg"}
: ${MODULES:="ext2 fat part_gpt search"}

umount=false

if [ -z "$EFI_PART" ] && [ -z "$TARGET" ]; then
    EFI_PART=/run/.boot-efi
    mount_boot_esp "$EFI_PART"
    umount=true
fi

: ${TARGET:="$EFI_PART/EFI/BOOT/BOOTAA64.EFI"}

fs="$(grub-probe "$BOOT_PART" -t fs)"
uuid="$(grub-probe "$BOOT_PART" -t fs_uuid)"
part="$(grub-probe "$BOOT_PART" -t drive | sed -e 's/(.*,/hd0,/' | tr -d ')')"
grub_path="$(grub-mkrelpath "$GRUB_DIR")"

if [ -z "$uuid" ]; then
    echo "Error: Unable to determine root filesystem UUID"
    exit 1
fi

echo "Filesystem: $fs"
echo "UUID: $uuid"
echo "Partition: $part"
echo "Relative path: $grub_path"

cat > /tmp/grub-core.cfg <<EOF
search.fs_uuid $uuid root $part
set prefix=(\$root)'$grub_path'
EOF

echo "Installing GRUB files..."
mkdir -p "$GRUB_DIR"
touch "$GRUB_DIR"/device.map
dd if=/dev/zero of="$GRUB_DIR"/grubenv bs=1024 count=1 2>/dev/null
cp -r /usr/share/grub/themes "$GRUB_DIR"
cp -r /usr/lib/grub/arm64-efi "$GRUB_DIR"
rm -f "$GRUB_DIR"/arm64-efi/*.module
mkdir -p "$GRUB_DIR"/{fonts,locale}
cp /usr/share/grub/unicode.pf2 "$GRUB_DIR"/fonts
for i in /usr/share/locale/*/LC_MESSAGES/grub.mo; do
    lc="$(echo "$i" | cut -d/ -f5)"
    cp "$i" "$GRUB_DIR"/locale/"$lc".mo
done

[[ $MODULES != *$fs* ]] && MODULES="$MODULES $fs"
echo "Core image modules: $MODULES"

echo "Generating GRUB image..."
grub-mkimage \
    --directory '/usr/lib/grub/arm64-efi' \
    -c /tmp/grub-core.cfg \
    --prefix "$part/boot/grub" \
    --output "$GRUB_DIR"/arm64-efi/core.efi \
    --format arm64-efi \
    --compression auto \
    $MODULES

cp "$GRUB_DIR"/arm64-efi/core.efi "$TARGET"

grub-mkconfig -o "$CONFIG"

$umount && umount "$EFI_PART"
true