The EFI shell is now packaged separately

[packages/efi-boot-update.git] / README

(U)EFI boot loaders updater
==========================

What is this for?
-----------------

(U)EFI systems boot using boot loaders on a special EFI System Partition.
Many different boot loaders may be present at a time. These are not only
traditional boot loaders like GRUB, but arbitrary 'EFI applications'.

Xen or Linux kernel can be built as an EFI application too and booted directly
from the EFI firmware. The problem is the kernels and data or config files
needed for boot must be stored on the EFI System Partition, but that is not
the place where they are installed on package upgrade. And it is hard to
install files from RPM packages there directly.

efi-boot-update script makes it easy to manage the files on the EFI system
partition. Those files are to be installed in the regular Linux system and
will be copied to the EFI system partition using rules defined in
/etc/efi-boot/update.d/*.conf files (efi-boot-update modules).

efi-boot-update will also manage EFI boot manager configuration, adding
the configured boot loaders to the platform boot menu, provided the
'efibootmgr' package is installed and functional.


What is this not?
-----------------

This is not another configuration interface for the boot loaders.
efi-boot-update can copy boot loader configuration files to the EFI system
partition, but it doesn't care about their contents or syntax. 

User Guide
----------

When efi-boot-update is installed it should be automatically called whenever
any package containing EFI boot loader/application (or data for such
application) is installed, upgraded or removed.

The administrator may alter efi-boot-update operation editing the
global /etc/efi-boot/update.conf file and the efi-boot-update modules
in /etc/efi-boot/update.d (these configure rules for a specific application).

The administrator is also responsible to edit any configuration files used by
the boot loaders (usually in /etc/efi-boot).

efi-boot-update should be manually called whenever any of these files
have been edited.

/etc/efi-boot/update.conf
.........................

This file provide global settings for the efi-boot-update script. The
file uses POSIX shell syntax to set shell variables. Values containing
spaces should be quoted with double quotes.

Following variables can be set there:

  * LABEL_PREFIX – the text to be prepended to every boot manager entry label
    created by efi-boot-update.
  * ORDER – preferred boot loader order. The value should contain
    space-separated names of efi-boot-update modules in /etc/efi/update.d
    (filenames there with '.conf' stripped).
  * PLATFORM_DIR – subdirectory of the 'EFI' directory in the EFI system
    partition where the EFI applications and data files will be stored.
    The value may contain '@ARCH@', which will be replaced with the
    architecture ('x64' or 'x32') for which the application was built (boot
    loaders may have both 32-bit and 64-bit versions and it may be different
    architecture that the one Linux is running).

modules in /etc/efi-boot/update.d
.................................

The *.conf files in the /etc/efi-boot/update.d directory provide rules for
installing a boot loader and creating the EFI boot manager label for it.

Following variables can be be set for each module:

  * ENABLED – when 'yes', then the files will be copied and a boot manager
    entry will be created for the application (provided BINARY is also set)
  * LABEL – label to use for the boot manager entry (defaults to the module
    name)
  * BINARY – name of the EFI binary installed in /boot/efi/EFI/$PLATFORM_DIR
    or a path to any EFI binary existing on the EFI system partition
  * ARGS – command line arguments for the EFI application
  * ARCH – architecture the binary is built for

The module may define more configurable variables, but should use own unique
prefix for them.

The module file should also contain a install_files() function definition
which defines what files are to be installed on the EFI system partition.

It can contain any shell code, but should not define any new global variables.
For convenience following are defined:

  * '$DESTDIR' variable – defines the directory where the files should be
    copied to that will be /boot/efi/EFI/$PLATFORM_DIR
  * 'update_file' function – copies a file to the EFI partition

    Usage:
       update_file [--missingok] SOURCE DEST

    Where:
        SOURCE      – absolute path to the file to be copied
        DEST        – destination file name. Absolute (but should be in
                      /boot/efi) or, preferably, Relative to $DESTDIR
	--missingok – when used, he command will not complain when the SOURCE
                      does not exist

    update_file behaviour depends on the '--verbose' and '--force' options
    passed to the efi-boot-update script.

Trouble shooting
----------------

> efi-boot-update: EFI system partition not mounted.

To boot from EFI you need a GUID Partition Table on your HDD containing the
EFI system partition. And efi-boot-update needs the partition mounted at
/boot/efi

When used with '--mount' option, efi-boot-update will try to find an mount the
partition, but for proper operation during package installation/upgrades the
partition should be always mounted.

> efi-boot-update: efibootmgr missing, won't update the boot manager
> configuration

efi-boot-update needs the 'efibootmgr' utility to update the EFI boot manager
configuration.

> efi-boot-update: efibootmgr does not work (efivars interface not available?)
> efi-boot-update: won't update boot manager configuration

The 'efibootmgr' does not always wark. It needs the 'efivars' kernel module
loaded (efi-boot-update takes care of that) and functioning correctly. This is
not always the case. The 'efivars' module works only when the kernel was
booted via EFI. If kernel has been started from from BIOS or is running
under Xen 'efibootmgr' won't work.

This causes a little boot strapping problem – you cannot use efi-boot-update
alone to configure system for the first UEFI boot.

efi-boot-update can still copy the files to the EFI partition, but one has
to manually select the boot loader via the EFI platform configuration
interface.