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✏️ Editing: 850_save_sysfs_uefi_vars.sh

# Determine what to use as UEFI bootloader file (UEFI_BOOTLOADER).
# A simplified uefivars replacement.

# USING_UEFI_BOOTLOADER empty or no explicit 'true' value means NO UEFI:
is_true $USING_UEFI_BOOTLOADER || return 0

# Don't do any guess work for boot loader, we will use systemd-bootx64.efi.
is_true $EFI_STUB && return 0

# Artificial 'for' clause that is run only once
# to be able to 'continue' with the code after it
# as soon as an usable UEFI bootloader file is found
# (the 'for' loop is run only once so that 'continue' is the same as 'break')
# which avoids dowdy looking code with deeply nested 'if...else' conditions:
for dummy in "once" ; do
    if test -f "$SECURE_BOOT_BOOTLOADER" ; then
        UEFI_BOOTLOADER="$SECURE_BOOT_BOOTLOADER"
    fi

# When the user has specified UEFI_BOOTLOADER in /etc/rear/local.conf use it if exists and is a regular file.
    # Double quotes are mandatory here because 'test -f' without any (possibly empty) argument results true:
    test -f "$UEFI_BOOTLOADER" && continue

# Now fall back step by step to more and more complicated autodetection methods
    # until a usable UEFI bootloader file is found or error out if nothing is found.
    # Keep the user informed what kind of autodetection method is tried next:

LogPrint "Trying to find what to use as UEFI bootloader..."
    # When UEFI_BOOTLOADER is not a regular file the user may have specified it
    # as a single string or as an array of filename globbing patterns for 'find'.
    # Because what the user has specified must have precedence over automatisms
    # this user specified 'find' must run before the other autodetections.
    # Using UEFI_BOOTLOADER as a single string or as an array works because
    # normal single string variables and arrays work reasonably compatible
    # i.e. "$VAR[@]" works for a single string variable VAR (results the string)
    # and "$ARR" works for an array variable (results the first array member) and
    # also ARR="string" works for an array variable (sets the first array member)
    # cf. https://github.com/rear/rear/pull/1212#issuecomment-283333298
    # On older systems where 'find' does not support '-iname' this does not make
    # it really worse because there 'find' just fails. I <jsmeix@suse.de> have
    # tested that on SUSE systems 'find' supports '-iname' down to SLES 10 SP4
    # cf. https://github.com/rear/rear/pull/1204#issuecomment-283045547
    for find_name_pattern in "${UEFI_BOOTLOADER[@]}" ; do
        # No need to test if find_name_pattern is empty because 'find' does not find anything with empty '-iname':
        UEFI_BOOTLOADER=$( find /boot -iname "$find_name_pattern" | tail -1 )
        # Continue with the code after the outer 'for' loop:
        test -f "$UEFI_BOOTLOADER" && continue 2
    done

LogPrint "Trying to find a 'well known file' to be used as UEFI bootloader..."
    UEFI_BOOTLOADER=$( find /boot/efi -name 'grub*.efi' | tail -1 )
    test -f "$UEFI_BOOTLOADER" && continue
    # In case we have an elilo bootloader we might be lucky with next statement:
    UEFI_BOOTLOADER=$( find /boot/efi -name 'elilo.efi' | tail -1 )
    test -f "$UEFI_BOOTLOADER" && continue
    # In case we have a 64-bit systemd bootloader we might be lucky with next statement:
    UEFI_BOOTLOADER=$( find /boot/EFI -name 'BOOTX64.EFI' | tail -1 )
    test -f "$UEFI_BOOTLOADER" && continue
    # Try more generic finds in whole /boot with case insensitive filename matching.
    # On older systems where 'find' does not support '-iname' this does not make it really worse because there 'find' just fails.
    for find_name_pattern in 'grub*.efi' 'elilo.efi' 'BOOTX64.EFI' ; do
        # No need to test if find_name_pattern is empty because 'find' does not find anything with empty '-iname':
        UEFI_BOOTLOADER=$( find /boot -iname "$find_name_pattern" | tail -1 )
        # Continue with the code after the outer 'for' loop:
        test -f "$UEFI_BOOTLOADER" && continue 2
    done

LogPrint "Trying to autodetect from EFI variables what to use as UEFI bootloader file..."
    # TODO: I <jsmeix@suse.de> cannot find a file named uefi-variables used elsewhere in the ReaR scripts
    # so that I wonder what the reason is why this file is stored in VAR_DIR and not in TMP_DIR?
    test -d "$VAR_DIR/recovery" || mkdir -p -m 755 $VAR_DIR/recovery
    local uefi_variables_file=$VAR_DIR/recovery/uefi-variables
    rm -f $uefi_variables_file
    local efibootmgr_output=$TMP_DIR/efibootmgr_output
    efibootmgr > "$efibootmgr_output"
    local uefi_dir=""
    local uefi_file=""
    local uefi_var=""
    local efi_data=""
    local efi_attr=""
    local boot_current=""
    local uefi_bootloader_DOS_path=""
    # Depending the directory ends on vars or efivars we need to treat it different.
    # See prep/default/320_include_uefi_env.sh how SYSFS_DIR_EFI_VARS is set:
    case "$SYSFS_DIR_EFI_VARS" in
        (/sys/firmware/efi/vars)
            for uefi_dir in $( ls $SYSFS_DIR_EFI_VARS ) ; do
                uefi_var=$( echo $uefi_dir | cut -d- -f 1 )
                [[ "$uefi_var" = "new_var" ]] && continue
                [[ "$uefi_var" = "del_var" ]] && continue
                efi_data="$( efibootmgr_read_var $uefi_var $efibootmgr_output )"
                [[ -z "$efi_data" ]] && efi_data="$( uefi_read_data $SYSFS_DIR_EFI_VARS/$uefi_dir/data )"
                efi_attr="$( uefi_read_attributes $SYSFS_DIR_EFI_VARS/$uefi_dir/attributes )"
                echo "$uefi_var $efi_attr: $efi_data" >> $uefi_variables_file
            done
            # Finding the correct EFI bootloader in use:
            boot_current=$( grep BootCurrent $uefi_variables_file | cut -d: -f2 | awk '{print $1}' ) # 0000
            uefi_bootloader_DOS_path=$( uefi_extract_bootloader $SYSFS_DIR_EFI_VARS/Boot${boot_current}-*/data )
            ;;
        (/sys/firmware/efi/efivars)
            for uefi_file in $( ls $SYSFS_DIR_EFI_VARS ) ; do
                uefi_var=$( echo $uefi_file | cut -d- -f 1 )
                efi_data="$( efibootmgr_read_var $uefi_var $efibootmgr_output )"
                [[ -z "$efi_data" ]] && efi_data="$( uefi_read_data $SYSFS_DIR_EFI_VARS/$uefi_file )"
                echo "$uefi_var $efi_attr: $efi_data" >> $uefi_variables_file
                #TODO: efi_attr how to extract??
            done
            # Finding the correct EFI bootloader in use:
            boot_current=$( grep BootCurrent $uefi_variables_file | cut -d: -f2 | awk '{print $1}' ) # 0000
            uefi_bootloader_DOS_path=$( uefi_extract_bootloader $SYSFS_DIR_EFI_VARS/Boot${boot_current}-* )
            ;;
        (*)
            BugError "EFI variables directory $SYSFS_DIR_EFI_VARS is neither /sys/firmware/efi/vars nor /sys/firmware/efi/efivars (ReaR supports only those)"
            ;;
    esac
    # Replace backslashes with slashes because uefi_bootloader_DOS_path contains path in DOS format:
    UEFI_BOOTLOADER="/boot/efi"$( echo "$uefi_bootloader_DOS_path" | sed -e 's;\\;/;g' )
    test -f "$UEFI_BOOTLOADER" && continue

# Error out when no usable UEFI bootloader file could be autodetected:
    Error "Cannot autodetect what to use as UEFI_BOOTLOADER, you have to manually specify it in $CONFIG_DIR/local.conf"

done

# Show to the user what will actually be used as UEFI bootloader file:
LogPrint "Using '$UEFI_BOOTLOADER' as UEFI bootloader file"

# Save the variables we need in recover mode into the rescue.conf file:
cat - <<EOF >> "$ROOTFS_DIR/etc/rear/rescue.conf"
USING_UEFI_BOOTLOADER=$USING_UEFI_BOOTLOADER
UEFI_BOOTLOADER="$UEFI_BOOTLOADER"
EOF

MR SKB