.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
Release 2.4 (rocko)
===================
This section provides migration information for moving to the Yocto
Project 2.4 Release (codename "rocko") from the prior release.
.. _migration-2.4-memory-resident-mode:
Memory Resident Mode
--------------------
A persistent mode is now available in BitBake's default operation,
replacing its previous "memory resident mode" (i.e.
``oe-init-build-env-memres``). Now you only need to set
:term:`BB_SERVER_TIMEOUT` to a timeout (in
seconds) and BitBake's server stays resident for that amount of time
between invocations. The ``oe-init-build-env-memres`` script has been
removed since a separate environment setup script is no longer needed.
.. _migration-2.4-packaging-changes:
Packaging Changes
-----------------
This section provides information about packaging changes that have
occurred:
- ``python3`` Changes:
- The main "python3" package now brings in all of the standard
Python 3 distribution rather than a subset. This behavior matches
what is expected based on traditional Linux distributions. If you
wish to install a subset of Python 3, specify ``python-core`` plus
one or more of the individual packages that are still produced.
- ``python3``: The ``bz2.py``, ``lzma.py``, and
``_compression.py`` scripts have been moved from the
``python3-misc`` package to the ``python3-compression`` package.
- ``binutils``: The ``libbfd`` library is now packaged in a separate
"libbfd" package. This packaging saves space when certain tools (e.g.
``perf``) are installed. In such cases, the tools only need
``libbfd`` rather than all the packages in ``binutils``.
- ``util-linux`` Changes:
- The ``su`` program is now packaged in a separate "util-linux-su"
package, which is only built when "pam" is listed in the
:term:`DISTRO_FEATURES` variable.
``util-linux`` should not be installed unless it is needed because
``su`` is normally provided through the shadow file format. The
main ``util-linux`` package has runtime dependencies (i.e.
:term:`RDEPENDS`) on the ``util-linux-su`` package
when "pam" is in :term:`DISTRO_FEATURES`.
- The ``switch_root`` program is now packaged in a separate
"util-linux-switch-root" package for small :term:`Initramfs` images that
do not need the whole ``util-linux`` package or the busybox
binary, which are both much larger than ``switch_root``. The main
``util-linux`` package has a recommended runtime dependency (i.e.
:term:`RRECOMMENDS`) on the
``util-linux-switch-root`` package.
- The ``ionice`` program is now packaged in a separate
"util-linux-ionice" package. The main ``util-linux`` package has a
recommended runtime dependency (i.e. :term:`RRECOMMENDS`) on the
``util-linux-ionice`` package.
- ``initscripts``: The ``sushell`` program is now packaged in a
separate "initscripts-sushell" package. This packaging change allows
systems to pull ``sushell`` in when ``selinux`` is enabled. The
change also eliminates needing to pull in the entire ``initscripts``
package. The main ``initscripts`` package has a runtime dependency
(i.e. :term:`RDEPENDS`) on the ``sushell`` package when "selinux" is in
:term:`DISTRO_FEATURES`.
- ``glib-2.0``: The ``glib-2.0`` package now has a recommended
runtime dependency (i.e. :term:`RRECOMMENDS`) on the ``shared-mime-info``
package, since large portions of GIO are not useful without the MIME
database. You can remove the dependency by using the
:term:`BAD_RECOMMENDATIONS` variable if
``shared-mime-info`` is too large and is not required.
- *Go Standard Runtime:* The Go standard runtime has been split out
from the main ``go`` recipe into a separate ``go-runtime`` recipe.
.. _migration-2.4-removed-recipes:
Removed Recipes
---------------
- ``acpitests``: This recipe is not maintained.
- ``autogen-native``: No longer required by Grub, oe-core, or
meta-oe.
- ``bdwgc``: Nothing in OpenEmbedded-Core requires this recipe. It
has moved to meta-oe.
- ``byacc``: This recipe was only needed by rpm 5.x and has moved to
meta-oe.
- ``gcc (5.4)``: The 5.4 series dropped the recipe in favor of 6.3 /
7.2.
- ``gnome-common``: Deprecated upstream and no longer needed.
- ``go-bootstrap-native``: Go 1.9 does its own bootstrapping so this
recipe has been removed.
- ``guile``: This recipe was only needed by ``autogen-native`` and
``remake``. The recipe is no longer needed by either of these
programs.
- ``libclass-isa-perl``: This recipe was previously needed for LSB 4,
no longer needed.
- ``libdumpvalue-perl``: This recipe was previously needed for LSB 4,
no longer needed.
- ``libenv-perl``: This recipe was previously needed for LSB 4, no
longer needed.
- ``libfile-checktree-perl``: This recipe was previously needed for
LSB 4, no longer needed.
- ``libi18n-collate-perl``: This recipe was previously needed for LSB
4, no longer needed.
- ``libiconv``: This recipe was only needed for ``uclibc``, which was
removed in the previous release. ``glibc`` and ``musl`` have their
own implementations. ``meta-mingw`` still needs ``libiconv``, so it
has been moved to ``meta-mingw``.
- ``libpng12``: This recipe was previously needed for LSB. The
current ``libpng`` is 1.6.x.
- ``libpod-plainer-perl``: This recipe was previously needed for LSB
4, no longer needed.
- ``linux-yocto (4.1)``: This recipe was removed in favor of 4.4,
4.9, 4.10 and 4.12.
- ``mailx``: This recipe was previously only needed for LSB
compatibility, and upstream is defunct.
- ``mesa (git version only)``: The git version recipe was stale with
respect to the release version.
- ``ofono (git version only)``: The git version recipe was stale with
respect to the release version.
- ``portmap``: This recipe is obsolete and is superseded by
``rpcbind``.
- ``python3-pygpgme``: This recipe is old and unmaintained. It was
previously required by ``dnf``, which has switched to official
``gpgme`` Python bindings.
- ``python-async``: This recipe has been removed in favor of the
Python 3 version.
- ``python-gitdb``: This recipe has been removed in favor of the
Python 3 version.
- ``python-git``: This recipe was removed in favor of the Python 3
version.
- ``python-mako``: This recipe was removed in favor of the Python 3
version.
- ``python-pexpect``: This recipe was removed in favor of the Python
3 version.
- ``python-ptyprocess``: This recipe was removed in favor of Python
the 3 version.
- ``python-pycurl``: Nothing is using this recipe in
OpenEmbedded-Core (i.e. ``meta-oe``).
- ``python-six``: This recipe was removed in favor of the Python 3
version.
- ``python-smmap``: This recipe was removed in favor of the Python 3
version.
- ``remake``: Using ``remake`` as the provider of ``virtual/make`` is
broken. Consequently, this recipe is not needed in OpenEmbedded-Core.
.. _migration-2.4-kernel-device-tree-move:
Kernel Device Tree Move
-----------------------
Kernel Device Tree support is now easier to enable in a kernel recipe.
The Device Tree code has moved to a :ref:`ref-classes-kernel-devicetree` class.
Functionality is automatically enabled for any recipe that inherits the
:ref:`kernel <ref-classes-kernel>` class and sets the :term:`KERNEL_DEVICETREE`
variable. The previous mechanism for doing this,
``meta/recipes-kernel/linux/linux-dtb.inc``, is still available to avoid
breakage, but triggers a deprecation warning. Future releases of the
Yocto Project will remove ``meta/recipes-kernel/linux/linux-dtb.inc``.
It is advisable to remove any ``require`` statements that request
``meta/recipes-kernel/linux/linux-dtb.inc`` from any custom kernel
recipes you might have. This will avoid breakage in post 2.4 releases.
.. _migration-2.4-package-qa-changes:
Package QA Changes
------------------
- The "unsafe-references-in-scripts" QA check has been removed.
- If you refer to ``${COREBASE}/LICENSE`` within
:term:`LIC_FILES_CHKSUM` you receive a
warning because this file is a description of the license for
OE-Core. Use ``${COMMON_LICENSE_DIR}/MIT`` if your recipe is
MIT-licensed and you cannot use the preferred method of referring to
a file within the source tree.
.. _migration-2.4-readme-changes:
``README`` File Changes
-----------------------
- The main Poky ``README`` file has been moved to the ``meta-poky``
layer and has been renamed ``README.poky``. A symlink has been
created so that references to the old location work.
- The ``README.hardware`` file has been moved to ``meta-yocto-bsp``. A
symlink has been created so that references to the old location work.
- A ``README.qemu`` file has been created with coverage of the
``qemu*`` machines.
.. _migration-2.4-miscellaneous-changes:
Miscellaneous Changes
---------------------
- The ``ROOTFS_PKGMANAGE_BOOTSTRAP`` variable and any references to it
have been removed. You should remove this variable from any custom
recipes.
- The ``meta-yocto`` directory has been removed.
.. note::
In the Yocto Project 2.1 release
meta-yocto
was renamed to
meta-poky
and the
meta-yocto
subdirectory remained to avoid breaking existing configurations.
- The ``maintainers.inc`` file, which tracks maintainers by listing a
primary person responsible for each recipe in OE-Core, has been moved
from ``meta-poky`` to OE-Core (i.e. from
``meta-poky/conf/distro/include`` to ``meta/conf/distro/include``).
- The :ref:`ref-classes-buildhistory` class now makes
a single commit per build rather than one commit per subdirectory in
the repository. This behavior assumes the commits are enabled with
:term:`BUILDHISTORY_COMMIT` = "1", which
is typical. Previously, the :ref:`ref-classes-buildhistory` class made one commit
per subdirectory in the repository in order to make it easier to see
the changes for a particular subdirectory. To view a particular
change, specify that subdirectory as the last parameter on the
``git show`` or ``git diff`` commands.
- The ``x86-base.inc`` file, which is included by all x86-based machine
configurations, now sets :term:`IMAGE_FSTYPES`
using ``?=`` to "live" rather than appending with ``+=``. This change
makes the default easier to override.
- BitBake fires multiple "BuildStarted" events when multiconfig is
enabled (one per configuration). For more information, see the
":ref:`bitbake-user-manual/bitbake-user-manual-metadata:events`"
section in the BitBake User Manual.
- By default, the ``security_flags.inc`` file sets a
:term:`GCCPIE` variable with an option to enable
Position Independent Executables (PIE) within ``gcc``. Enabling PIE
in the GNU C Compiler (GCC), makes Return Oriented Programming (ROP)
attacks much more difficult to execute.
- OE-Core now provides a ``bitbake-layers`` plugin that implements a
"create-layer" subcommand. The implementation of this subcommand has
resulted in the ``yocto-layer`` script being deprecated and will
likely be removed in the next Yocto Project release.
- The ``vmdk``, ``vdi``, and ``qcow2`` image file types are now used in
conjunction with the "wic" image type through :term:`CONVERSION_CMD`.
Consequently, the equivalent image types are now ``wic.vmdk``,
``wic.vdi``, and ``wic.qcow2``, respectively.
- ``do_image_<type>[depends]`` has replaced ``IMAGE_DEPENDS_<type>``.
If you have your own classes that implement custom image types, then
you need to update them.
- OpenSSL 1.1 has been introduced. However, the default is still 1.0.x
through the :term:`PREFERRED_VERSION`
variable. This preference is set is due to the remaining
compatibility issues with other software. The
:term:`PROVIDES` variable in the openssl 1.0 recipe
now includes "openssl10" as a marker that can be used in
:term:`DEPENDS` within recipes that build software
that still depend on OpenSSL 1.0.
- To ensure consistent behavior, BitBake's "-r" and "-R" options (i.e.
prefile and postfile), which are used to read or post-read additional
configuration files from the command line, now only affect the
current BitBake command. Before these BitBake changes, these options
would "stick" for future executions.