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# 100_create_efiboot.sh
# USB device needs to be formatted with command `rear format -- --efi /dev/<device_name>'

is_true $USING_UEFI_BOOTLOADER || return 0

Log "Configuring device for EFI boot"

# $BUILD_DIR is not present at this stage, temp dir will be used instead.
# Slackware version of mktemp requires 6 Xs in template and
# plain 'mktemp' uses XXXXXXXXXX by default (at least on SLES11 and openSUSE Leap 15.0)
# so that we comply with the 'mktemp' default to avoid 'mktemp' errors "too few X's in template":
EFI_MPT=$( mktemp -d /tmp/rear-efi.XXXXXXXXXX ) || Error "mktemp failed to create mount point '/tmp/rear-efi.XXXXXXXXXX' for EFI partition"

uefi_bootloader_basename=$( basename "$UEFI_BOOTLOADER" )
EFI_LABEL="REAR-EFI"
EFI_PART="/dev/disk/by-label/${EFI_LABEL}"
EFI_DIR="/EFI/BOOT"
EFI_DST="${EFI_MPT}/${EFI_DIR}"

# Fail if EFI partition is not present
if [[ ! -b ${EFI_PART} ]]; then
    Error "${EFI_PART} is not block device. Use \`rear format -- --efi <USB_device_file>' for correct format"
fi

# Mount EFI partition
mount $EFI_PART $EFI_MPT || Error "Failed to mount EFI partition '$EFI_PART' at '$EFI_MPT'"

# Create EFI friendly dir structure
mkdir -p $EFI_DST || Error "Failed to create directory '$EFI_DST'"

# Copy boot loader
# The SECURE_BOOT_BOOTLOADER related code below is based on the code in output/ISO/Linux-i386/250_populate_efibootimg.sh
# because I <jsmeix@suse.de> noticed that Secure Boot works with ISO at least for me, cf.
# https://github.com/rear/rear/pull/3025#issuecomment-1635876186
# but not with USB, cf.
# https://github.com/rear/rear/pull/3025#issuecomment-1643774477
# so I tried to re-use the ISO Secure Boot code for USB
# which made Secure Boot "just work" for me with USB
# but I had to do some (minor) adaptions to make it work
# within the existing USB code, cf.
# https://github.com/rear/rear/pull/3031#issuecomment-1653443454
# Copy UEFI bootloader:
if test -f "$SECURE_BOOT_BOOTLOADER" ; then
    # For a technical description of Shim see https://mjg59.dreamwidth.org/19448.html
    # Shim is a signed EFI binary that is a first stage bootloader
    # that loads and executes another (signed) EFI binary
    # which normally is a second stage bootloader
    # which normally is a GRUB EFI binary
    # which normally is available as a file named grub*.efi
    # so when SECURE_BOOT_BOOTLOADER is used as UEFI_BOOTLOADER
    # (cf. rescue/default/850_save_sysfs_uefi_vars.sh)
    # then Shim (usually shim.efi) must be copied as EFI/BOOT/BOOTX64.efi
    # and Shim's second stage bootloader must be also copied where Shim already is.
    DebugPrint "Using '$SECURE_BOOT_BOOTLOADER' as first stage Secure Boot bootloader BOOTX64.efi"
    cp -L $v "$SECURE_BOOT_BOOTLOADER" "$EFI_DST/BOOTX64.efi" || Error "Failed to copy SECURE_BOOT_BOOTLOADER '$SECURE_BOOT_BOOTLOADER' to $EFI_DST/BOOTX64.efi"
    # When Shim is used, its second stage bootloader can be actually anything
    # named grub*.efi (second stage bootloader is Shim compile time option), see
    # http://www.rodsbooks.com/efi-bootloaders/secureboot.html#initial_shim
    local uefi_bootloader_dirname="$( dirname $SECURE_BOOT_BOOTLOADER )"
    local second_stage_UEFI_bootloader_files="$( echo $uefi_bootloader_dirname/grub*.efi )"
    # Avoid 'nullglob' pitfall when nothing matches .../grub*.efi which would result
    # an invalid "cp -v /var/tmp/.../EFI/BOOT/" command that fails
    # cf. https://github.com/rear/rear/issues/1921
    test "$second_stage_UEFI_bootloader_files" || Error "Could not find second stage Secure Boot bootloader $uefi_bootloader_dirname/grub*.efi"
    DebugPrint "Using second stage Secure Boot bootloader files: $second_stage_UEFI_bootloader_files"
    cp -L $v $second_stage_UEFI_bootloader_files $EFI_DST/ || Error "Failed to copy second stage Secure Boot bootloader files"
else
    cp -L $v "$UEFI_BOOTLOADER" "$EFI_DST/BOOTX64.efi" || Error "Failed to copy UEFI_BOOTLOADER '$UEFI_BOOTLOADER' to $EFI_DST/BOOTX64.efi"
fi
cp $v $UEFI_BOOTLOADER "$EFI_DST/BOOTX64.efi" || Error "Failed to copy UEFI_BOOTLOADER '$UEFI_BOOTLOADER' to $EFI_DST/BOOTX64.efi"

# Copy kernel
cp -pL $v "$KERNEL_FILE" "$EFI_DST/kernel" || Error "Failed to copy KERNEL_FILE '$KERNEL_FILE' to $EFI_DST/kernel"

# Copy initrd
cp -p $v "$TMP_DIR/$REAR_INITRD_FILENAME" "$EFI_DST/$REAR_INITRD_FILENAME" || Error "Failed to copy initrd to $EFI_DST/$REAR_INITRD_FILENAME"

Log "Copied kernel $KERNEL_FILE and initrd $REAR_INITRD_FILENAME to $EFI_DST"

# Configure elilo for EFI boot
if test "$uefi_bootloader_basename" = "elilo.efi" ; then
    Log "Configuring elilo for EFI boot"

    # Create config for elilo
    Log "Creating ${EFI_DST}/elilo.conf"

    create_ebiso_elilo_conf > ${EFI_DST}/elilo.conf

# Configure grub for EFI boot or die
else
    # Hope this assumption is not wrong ...
    if has_binary grub-install grub2-install; then

        # Choose right grub binary
        # Issue #849
        if has_binary grub2-install; then
            NUM=2
        fi

        GRUB_INSTALL=grub${NUM}-install

        # What version of grub are we using
        # substr() for awk did not work as expected for this reason cut was used
        # First charecter should be enough to identify grub version
        grub_version=$($GRUB_INSTALL --version | awk '{print $NF}' | cut -c1-1)

        case ${grub_version} in
            0)
                Log "Configuring grub 0.97 for EFI boot"

                # Create config for grub 0.97
                cat > ${EFI_DST}/BOOTX64.conf << EOF
default=0
timeout=5

title Relax-and-Recover (no Secure Boot)
    kernel ${EFI_DIR}/kernel $KERNEL_CMDLINE
    initrd ${EFI_DIR}/$REAR_INITRD_FILENAME
EOF
            ;;
            2)
                Log "Configuring grub 2.0 for EFI boot"
                # We need to explicitly set $root variable to $EFI_LABEL
                # (currently "REAR-EFI") in Grub because default $root would
                # point to memdisk, where kernel and initrd are NOT present.
                # Variable grub2_set_usb_root will be used in later call of
                # create_grub2_cfg().
                grub2_set_usb_root="search --no-floppy --set=root --label ${EFI_LABEL}"

                # Create config for grub 2.0
                create_grub2_cfg ${EFI_DIR}/kernel ${EFI_DIR}/$REAR_INITRD_FILENAME > ${EFI_DST}/grub.cfg

                # Create bootloader, this overwrite BOOTX64.efi copied in previous step ...
                # Create BOOTX86.efi but only if we are NOT secure booting.
                # We are not able to create signed boot loader
                # so we need to reuse existing one.
                # See issue #1374
                # build_bootx86_efi () can be safely used for other scenarios.
                if ! test -f "$SECURE_BOOT_BOOTLOADER" ; then
                    build_bootx86_efi ${EFI_DST}/BOOTX64.efi ${EFI_DST}/grub.cfg "/boot" "$UEFI_BOOTLOADER"
                fi
            ;;
            *)
                BugError "Neither grub 0.97 nor 2.0"
            ;;
        esac
    else
        BugIfError "Unknown EFI bootloader"
    fi
fi

# Do cleanup of EFI temporary mount point
Log "Doing cleanup of ${EFI_MPT}"

umount ${EFI_MPT}
if [[ $? -eq 0 ]]; then
    rmdir ${EFI_MPT}
    LogIfError "Could not remove temporary directory ${EFI_MPT}, please check manually"
else
    Log "Could not umount ${EFI_MPT}, please check manually"
fi

Log "Created EFI configuration for USB"