mirror of
git://git.yoctoproject.org/poky.git
synced 2025-07-19 21:09:03 +02:00
d4bdafa8df
(From yocto-docs rev: 955f08c8d49fabd6022570e4d0a7442f06f6049b) Signed-off-by: Scott Rifenbark <srifenbark@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
997 lines
49 KiB
XML
997 lines
49 KiB
XML
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"
|
|
[<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] >
|
|
|
|
<appendix id='sdk-appendix-customizing'>
|
|
|
|
<title>Customizing the SDK</title>
|
|
|
|
<para>
|
|
This appendix presents customizations you can apply to both the standard
|
|
and extensible SDK.
|
|
Each subsection identifies the type of SDK to which the section applies.
|
|
</para>
|
|
|
|
<section id='sdk-configuring-the-extensible-sdk'>
|
|
<title>Configuring the Extensible SDK</title>
|
|
|
|
<para>
|
|
The extensible SDK primarily consists of a pre-configured copy of
|
|
the OpenEmbedded build system from which it was produced.
|
|
Thus, the SDK's configuration is derived using that build system and
|
|
the following filters, which the OpenEmbedded build system applies
|
|
against <filename>local.conf</filename> and
|
|
<filename>auto.conf</filename> if they are present:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
Variables whose values start with "/" are excluded since the
|
|
assumption is that those values are paths that are likely to
|
|
be specific to the build host.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Variables listed in
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_LOCAL_CONF_BLACKLIST'><filename>SDK_LOCAL_CONF_BLACKLIST</filename></ulink>
|
|
are excluded.
|
|
The default value blacklists
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-CONF_VERSION'><filename>CONF_VERSION</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-BB_NUMBER_THREADS'><filename>BB_NUMBER_THREADS</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PARALLEL_MAKE'><filename>PARALLEL_MAKE</filename></ulink>,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PRSERV_HOST'><filename>PRSERV_HOST</filename></ulink>,
|
|
and
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></ulink>.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Variables listed in
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_LOCAL_CONF_WHITELIST'><filename>SDK_LOCAL_CONF_WHITELIST</filename></ulink>
|
|
are included.
|
|
Including a variable in the value of
|
|
<filename>SDK_LOCAL_CONF_WHITELIST</filename> overrides either
|
|
of the above two conditions.
|
|
The default value is blank.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Classes inherited globally with
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-INHERIT'><filename>INHERIT</filename></ulink>
|
|
that are listed in
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_INHERIT_BLACKLIST'><filename>SDK_INHERIT_BLACKLIST</filename></ulink>
|
|
are disabled.
|
|
Using <filename>SDK_INHERIT_BLACKLIST</filename> to disable
|
|
these classes is is the typical method to disable classes that
|
|
are problematic or unnecessary in the SDK context.
|
|
The default value blacklists the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-buildhistory'><filename>buildhistory</filename></ulink>
|
|
and
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#ref-classes-icecc'><filename>icecc</filename></ulink>
|
|
classes.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
Additionally, the contents of <filename>conf/sdk-extra.conf</filename>,
|
|
when present, are appended to the end of
|
|
<filename>conf/local.conf</filename> within the produced SDK, without
|
|
any filtering.
|
|
The <filename>sdk-extra.conf</filename> file is particularly useful
|
|
if you want to set a variable value just for the SDK and not the
|
|
OpenEmbedded build system used to create the SDK.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='adjusting-the-extensible-sdk-to-suit-your-build-system-setup'>
|
|
<title>Adjusting the Extensible SDK to Suit Your Build System Setup</title>
|
|
|
|
<para>
|
|
In most cases, the extensible SDK defaults should work.
|
|
However, some cases exist for which you might consider making
|
|
adjustments:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
If your SDK configuration inherits additional classes
|
|
using the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-INHERIT'><filename>INHERIT</filename></ulink>
|
|
variable and you do not need or want those classes enabled in
|
|
the SDK, you can blacklist them by adding them to the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_INHERIT_BLACKLIST'><filename>SDK_INHERIT_BLACKLIST</filename></ulink>
|
|
variable.
|
|
The default value of <filename>SDK_INHERIT_BLACKLIST</filename>
|
|
is set using the "?=" operator.
|
|
Consequently, you will need to either set the complete value
|
|
using "=" or append the value using "_append".
|
|
</para></listitem>
|
|
<listitem><para>
|
|
If you have classes or recipes that add additional tasks to
|
|
the standard build flow (i.e. that execute as part of building
|
|
the recipe as opposed to needing to be called explicitly), then
|
|
you need to do one of the following:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
Ensure the tasks are shared state tasks (i.e. their
|
|
output is saved to and can be restored from the shared
|
|
state cache), or that the tasks are able to be
|
|
produced quickly from a task that is a shared state
|
|
task and add the task name to the value of
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_RECRDEP_TASKS'><filename>SDK_RECRDEP_TASKS</filename></ulink>.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Disable the tasks if they are added by a class and
|
|
you do not need the functionality the class provides
|
|
in the extensible SDK.
|
|
To disable the tasks, add the class to
|
|
<filename>SDK_INHERIT_BLACKLIST</filename> as previously
|
|
described.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Generally, you want to have a shared state mirror set up so
|
|
users of the SDK can add additional items to the SDK after
|
|
installation without needing to build the items from source.
|
|
See the
|
|
"<link linkend='sdk-providing-additional-installable-extensible-sdk-content'>Providing Additional Installable Extensible SDK Content</link>"
|
|
section for information.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
If you want users of the SDK to be able to easily update the
|
|
SDK, you need to set the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_UPDATE_URL'><filename>SDK_UPDATE_URL</filename></ulink>
|
|
variable.
|
|
For more information, see the
|
|
"<link linkend='sdk-providing-updates-after-installing-the-extensible-sdk'>Providing Updates After Installing the Extensible SDK</link>"
|
|
section.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
If you have adjusted the list of files and directories that
|
|
appear in
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-COREBASE'><filename>COREBASE</filename></ulink>
|
|
(other than layers that are enabled through
|
|
<filename>bblayers.conf</filename>), then you must list these
|
|
files in
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-COREBASE_FILES'><filename>COREBASE_FILES</filename></ulink>
|
|
so that the files are copied into the SDK.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
If your OpenEmbedded build system setup uses a different
|
|
environment setup script other than
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#structure-core-script'><filename>&OE_INIT_FILE;</filename></ulink>
|
|
or
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#structure-memres-core-script'><filename>oe-init-build-env-memres</filename></ulink>,
|
|
then you must set
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-OE_INIT_ENV_SCRIPT'><filename>OE_INIT_ENV_SCRIPT</filename></ulink>
|
|
to point to the environment setup script you use.
|
|
<note>
|
|
You must also reflect this change in the value used for the
|
|
<filename>COREBASE_FILES</filename> variable as previously
|
|
described.
|
|
</note>
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-changing-the-appearance-of-the-extensible-sdk'>
|
|
<title>Changing the Appearance of the Extensible SDK</title>
|
|
|
|
<para>
|
|
You can change the title shown by the SDK installer by setting the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_TITLE'><filename>SDK_TITLE</filename></ulink>
|
|
variable.
|
|
By default, this title is derived from
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO_NAME'><filename>DISTRO_NAME</filename></ulink>
|
|
when it is set.
|
|
If the <filename>DISTRO_NAME</filename> variable is not set, the title
|
|
is derived from the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-DISTRO'><filename>DISTRO</filename></ulink>
|
|
variable.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-providing-updates-after-installing-the-extensible-sdk'>
|
|
<title>Providing Updates After Installing the Extensible SDK</title>
|
|
|
|
<para>
|
|
When you make changes to your configuration or to the metadata and
|
|
if you want those changes to be reflected in installed SDKs, you need
|
|
to perform additional steps to make it possible for those that use
|
|
the SDK to update their installations with the
|
|
<filename>devtool sdk-update</filename> command:
|
|
<orderedlist>
|
|
<listitem><para>
|
|
Arrange to be created a directory that can be shared over
|
|
HTTP or HTTPS.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Set the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_UPDATE_URL'><filename>SDK_UPDATE_URL</filename></ulink>
|
|
variable to point to the corresponding HTTP or HTTPS URL.
|
|
Setting this variable causes any SDK built to default to that
|
|
URL and thus, the user does not have to pass the URL to the
|
|
<filename>devtool sdk-update</filename> command.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Build the extensible SDK normally (i.e., use the
|
|
<filename>bitbake -c populate_sdk_ext</filename> <replaceable>imagename</replaceable>
|
|
command).
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Publish the SDK using the following command:
|
|
<literallayout class='monospaced'>
|
|
$ oe-publish-sdk <replaceable>some_path</replaceable>/sdk-installer.sh <replaceable>path_to_shared/http_directory</replaceable>
|
|
</literallayout>
|
|
You must repeat this step each time you rebuild the SDK
|
|
with changes that you want to make available through the
|
|
update mechanism.
|
|
</para></listitem>
|
|
</orderedlist>
|
|
</para>
|
|
|
|
<para>
|
|
Completing the above steps allows users of the existing SDKs to
|
|
simply run <filename>devtool sdk-update</filename> to retrieve the
|
|
latest updates.
|
|
See the
|
|
"<link linkend='sdk-updating-the-extensible-sdk'>Updating the Extensible SDK</link>"
|
|
section for further information.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-providing-additional-installable-extensible-sdk-content'>
|
|
<title>Providing Additional Installable Extensible SDK Content</title>
|
|
|
|
<para>
|
|
If you want the users of the extensible SDK you are building to be
|
|
able to add items to the SDK without needing to build the
|
|
items from source, you need to do a number of things:
|
|
<orderedlist>
|
|
<listitem><para>
|
|
Ensure the additional items you want the user to be able to
|
|
install are actually built.
|
|
You can ensure these items are built a number of different
|
|
ways: 1) Build them explicitly, perhaps using one or more
|
|
"meta" recipes that depend on lists of other recipes to keep
|
|
things tidy, or 2) Build the "world" target and set
|
|
<filename>EXCLUDE_FROM_WORLD_pn-</filename><replaceable>recipename</replaceable>
|
|
for the recipes you do not want built.
|
|
See the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-EXCLUDE_FROM_WORLD'><filename>EXCLUDE_FROM_WORLD</filename></ulink>
|
|
variable for additional information.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Expose the <filename>sstate-cache</filename> directory
|
|
produced by the build.
|
|
Typically, you expose this directory over HTTP or HTTPS.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Set the appropriate configuration so that the produced SDK
|
|
knows how to find the configuration.
|
|
The variable you need to set is
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SSTATE_MIRRORS'><filename>SSTATE_MIRRORS</filename></ulink>:
|
|
<literallayout class='monospaced'>
|
|
SSTATE_MIRRORS = "file://.* http://<replaceable>example</replaceable>.com/<replaceable>some_path</replaceable>/sstate-cache/PATH"
|
|
</literallayout>
|
|
You can set the <filename>SSTATE_MIRRORS</filename> variable
|
|
in two different places:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
If the mirror value you are setting is appropriate to
|
|
be set for both the OpenEmbedded build system that is
|
|
actually building the SDK and the SDK itself (i.e. the
|
|
mirror is accessible in both places or it will fail
|
|
quickly on the OpenEmbedded build system side, and its
|
|
contents will not interfere with the build), then you
|
|
can set the variable in your
|
|
<filename>local.conf</filename> or custom distro
|
|
configuration file.
|
|
You can then "whitelist" the variable through
|
|
to the SDK by adding the following:
|
|
<literallayout class='monospaced'>
|
|
SDK_LOCAL_CONF_WHITELIST = "SSTATE_MIRRORS"
|
|
</literallayout>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Alternatively, if you just want to set the
|
|
<filename>SSTATE_MIRRORS</filename> variable's value
|
|
for the SDK alone, create a
|
|
<filename>conf/sdk-extra.conf</filename> either in
|
|
your
|
|
<ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
|
|
or within any layer and put your
|
|
<filename>SSTATE_MIRRORS</filename> setting within
|
|
that file.
|
|
<note>
|
|
This second option is the safest option should
|
|
you have any doubts as to which method to use when
|
|
setting <filename>SSTATE_MIRRORS</filename>.
|
|
</note>
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para></listitem>
|
|
</orderedlist>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-minimizing-the-size-of-the-extensible-sdk-installer-download'>
|
|
<title>Minimizing the Size of the Extensible SDK Installer Download</title>
|
|
|
|
<para>
|
|
By default, the extensible SDK bundles the shared state artifacts for
|
|
everything needed to reconstruct the image for which the SDK was built.
|
|
This bundling can lead to an SDK installer file that is a Gigabyte or
|
|
more in size.
|
|
If the size of this file causes a problem, you can build an SDK that
|
|
has just enough in it to install and provide access to the
|
|
<filename>devtool command</filename> by setting the following in your
|
|
configuration:
|
|
<literallayout class='monospaced'>
|
|
SDK_EXT_TYPE = "minimal"
|
|
</literallayout>
|
|
Setting
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_EXT_TYPE'><filename>SDK_EXT_TYPE</filename></ulink>
|
|
to "minimal" produces an SDK installer that is around 35 Mbytes in
|
|
size, which downloads and installs quickly.
|
|
You need to realize, though, that the minimal installer does not
|
|
install any libraries or tools out of the box.
|
|
These must be installed either "on the fly" or through actions you
|
|
perform using <filename>devtool</filename> or explicitly with the
|
|
<filename>devtool sdk-install</filename> command.
|
|
</para>
|
|
|
|
<para>
|
|
In most cases, when building a minimal SDK you will need to also enable
|
|
bringing in the information on a wider range of packages produced by
|
|
the system.
|
|
This is particularly true so that <filename>devtool add</filename>
|
|
is able to effectively map dependencies it discovers in a source tree
|
|
to the appropriate recipes.
|
|
Also so that the <filename>devtool search</filename> command
|
|
is able to return useful results.
|
|
</para>
|
|
|
|
<para>
|
|
To facilitate this wider range of information, you would additionally
|
|
set the following:
|
|
<literallayout class='monospaced'>
|
|
SDK_INCLUDE_PKGDATA = "1"
|
|
</literallayout>
|
|
See the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-SDK_INCLUDE_PKGDATA'><filename>SDK_INCLUDE_PKGDATA</filename></ulink>
|
|
variable for additional information.
|
|
</para>
|
|
|
|
<para>
|
|
Setting the <filename>SDK_INCLUDE_PKGDATA</filename> variable as
|
|
shown causes the "world" target to be built so that information
|
|
for all of the recipes included within it are available.
|
|
Having these recipes available increases build time significantly and
|
|
increases the size of the SDK installer by 30-80 Mbytes depending on
|
|
how many recipes are included in your configuration.
|
|
</para>
|
|
|
|
<para>
|
|
You can use
|
|
<filename>EXCLUDE_FROM_WORLD_pn-</filename><replaceable>recipename</replaceable>
|
|
for recipes you want to exclude.
|
|
However, it is assumed that you would need to be building the "world"
|
|
target if you want to provide additional items to the SDK.
|
|
Consequently, building for "world" should not represent undue
|
|
overhead in most cases.
|
|
<note>
|
|
If you set <filename>SDK_EXT_TYPE</filename> to "minimal",
|
|
then providing a shared state mirror is mandatory so that items
|
|
can be installed as needed.
|
|
See the
|
|
"<link linkend='sdk-providing-additional-installable-extensible-sdk-content'>Providing Additional Installable Extensible SDK Content</link>"
|
|
section for more information.
|
|
</note>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-a-closer-look-at-devtool-add'>
|
|
<title>A Closer Look at <filename>devtool add</filename></title>
|
|
|
|
<para>
|
|
The <filename>devtool add</filename> command automatically creates a
|
|
recipe based on the source tree with which you provide it.
|
|
Currently, the command has support for the following:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
Autotools (<filename>autoconf</filename> and
|
|
<filename>automake</filename>)
|
|
</para></listitem>
|
|
<listitem><para>
|
|
<filename>CMake</filename>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
<filename>Scons</filename>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
<filename>qmake</filename>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Plain <filename>Makefile</filename>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Out-of-tree kernel module
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Binary package (i.e. "-b" option)
|
|
</para></listitem>
|
|
<listitem><para>
|
|
<filename>Node.js</filename> module through
|
|
<filename>npm</filename>
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Python modules that use <filename>setuptools</filename>
|
|
or <filename>distutils</filename>
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
|
|
<para>
|
|
Apart from binary packages, the determination of how a source tree
|
|
should be treated is automatic based on the files present within
|
|
that source tree.
|
|
For example, if a <filename>CMakeLists.txt</filename> file is found,
|
|
then the source tree is assumed to be using
|
|
<filename>CMake</filename> and is treated accordingly.
|
|
<note>
|
|
In most cases, you need to edit the automatically generated
|
|
recipe in order to make it build properly.
|
|
Typically, you would go through several edit and build cycles
|
|
until you can build the recipe.
|
|
Once the recipe can be built, you could use possible further
|
|
iterations to test the recipe on the target device.
|
|
</note>
|
|
</para>
|
|
|
|
<para>
|
|
The remainder of this section covers specifics regarding how parts
|
|
of the recipe are generated.
|
|
</para>
|
|
|
|
<section id='sdk-name-and-version'>
|
|
<title>Name and Version</title>
|
|
|
|
<para>
|
|
If you do not specify a name and version on the command
|
|
line, <filename>devtool add</filename> attempts to determine
|
|
the name and version of the software being built from
|
|
various metadata within the source tree.
|
|
Furthermore, the command sets the name of the created recipe
|
|
file accordingly.
|
|
If the name or version cannot be determined, the
|
|
<filename>devtool add</filename> command prints an error and
|
|
you must re-run the command with both the name and version
|
|
or just the name or version specified.
|
|
</para>
|
|
|
|
<para>
|
|
Sometimes the name or version determined from the source tree
|
|
might be incorrect.
|
|
For such a case, you must run the following commands:
|
|
<literallayout class='monospaced'>
|
|
$ devtool reset -n <replaceable>recipename</replaceable>
|
|
</literallayout>
|
|
After running the <filename>devtool reset</filename> command,
|
|
you need to run <filename>devtool add</filename> again and
|
|
provide the name or the version.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-dependency-detection-and-mapping'>
|
|
<title>Dependency Detection and Mapping</title>
|
|
|
|
<para>
|
|
The <filename>devtool add</filename> command attempts to
|
|
detect build-time dependencies and map them to other recipes
|
|
in the system.
|
|
During this mapping, the command fills in the names of those
|
|
recipes in the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
|
|
value within the recipe.
|
|
If a dependency cannot be mapped, then a comment is placed in
|
|
the recipe indicating such.
|
|
The inability to map a dependency might be caused because the
|
|
naming is not recognized or because the dependency simply is
|
|
not available.
|
|
For cases where the dependency is not available, you must use
|
|
the <filename>devtool add</filename> command to add an
|
|
additional recipe to satisfy the dependency and then come
|
|
back to the first recipe and add its name to
|
|
<filename>DEPENDS</filename>.
|
|
</para>
|
|
|
|
<para>
|
|
If you need to add runtime dependencies, you can do so by
|
|
adding the following to your recipe:
|
|
<literallayout class='monospaced'>
|
|
RDEPENDS_${PN} += "dependency1 dependency2 ..."
|
|
</literallayout>
|
|
<note>
|
|
The <filename>devtool add</filename> command often cannot
|
|
distinguish between mandatory and optional dependencies.
|
|
Consequently, some of the detected dependencies might
|
|
in fact be optional.
|
|
When in doubt, consult the documentation or the configure
|
|
script for the software the recipe is building for further
|
|
details.
|
|
In some cases, you might find you can substitute the
|
|
dependency for an option to disable the associated
|
|
functionality passed to the configure script.
|
|
</note>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-license-detection'>
|
|
<title>License Detection</title>
|
|
|
|
<para>
|
|
The <filename>devtool add</filename> command attempts to
|
|
determine if the software you are adding is able to be
|
|
distributed under a common open-source license and sets the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-LICENSE'><filename>LICENSE</filename></ulink>
|
|
value accordingly.
|
|
You should double-check this value against the documentation
|
|
or source files for the software you are building and update
|
|
that <filename>LICENSE</filename> value if necessary.
|
|
</para>
|
|
|
|
<para>
|
|
The <filename>devtool add</filename> command also sets the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-LIC_FILES_CHKSUM'><filename>LIC_FILES_CHKSUM</filename></ulink>
|
|
value to point to all files that appear to be license-related.
|
|
However, license statements often appear in comments at the top
|
|
of source files or within documentation.
|
|
Consequently, you might need to amend the
|
|
<filename>LIC_FILES_CHKSUM</filename> variable to point to one
|
|
or more of those comments if present.
|
|
Setting <filename>LIC_FILES_CHKSUM</filename> is particularly
|
|
important for third-party software.
|
|
The command attempts to ensure correct licensing should you
|
|
upgrade the recipe to a newer upstream version in future.
|
|
Any change in licensing is detected and you receive an error
|
|
prompting you to check the license text again.
|
|
</para>
|
|
|
|
<para>
|
|
If the <filename>devtool add</filename> command cannot
|
|
determine licensing information, the
|
|
<filename>LICENSE</filename> value is set to "CLOSED" and the
|
|
<filename>LIC_FILES_CHKSUM</filename> vaule remains unset.
|
|
This behavior allows you to continue with development but is
|
|
unlikely to be correct in all cases.
|
|
Consequently, you should check the documentation or source
|
|
files for the software you are building to determine the actual
|
|
license.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-adding-makefile-only-software'>
|
|
<title>Adding Makefile-Only Software</title>
|
|
|
|
<para>
|
|
The use of <filename>make</filename> by itself is very common
|
|
in both proprietary and open source software.
|
|
Unfortunately, Makefiles are often not written with
|
|
cross-compilation in mind.
|
|
Thus, <filename>devtool add</filename> often cannot do very
|
|
much to ensure that these Makefiles build correctly.
|
|
It is very common, for example, to explicitly call
|
|
<filename>gcc</filename> instead of using the
|
|
<filename>CC</filename> variable.
|
|
Usually, in a cross-compilation environment,
|
|
<filename>gcc</filename> is the compiler for the build host
|
|
and the cross-compiler is named something similar to
|
|
<filename>arm-poky-linux-gnueabi-gcc</filename> and might
|
|
require some arguments (e.g. to point to the associated sysroot
|
|
for the target machine).
|
|
</para>
|
|
|
|
<para>
|
|
When writing a recipe for Makefile-only software, keep the
|
|
following in mind:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
You probably need to patch the Makefile to use
|
|
variables instead of hardcoding tools within the
|
|
toolchain such as <filename>gcc</filename> and
|
|
<filename>g++</filename>.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
The environment in which <filename>make</filename> runs
|
|
is set up with various standard variables for
|
|
compilation (e.g. <filename>CC</filename>,
|
|
<filename>CXX</filename>, and so forth) in a similar
|
|
manner to the environment set up by the SDK's
|
|
environment setup script.
|
|
One easy way to see these variables is to run the
|
|
<filename>devtool build</filename> command on the
|
|
recipe and then look in
|
|
<filename>oe-logs/run.do_compile</filename>.
|
|
Towards the top of this file you will see a list of
|
|
environment variables that are being set.
|
|
You can take advantage of these variables within the
|
|
Makefile.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
If the Makefile sets a default for a variable, that
|
|
default overrides the value set in the environment,
|
|
which is usually not desirable.
|
|
In this situation, you can either patch the Makefile
|
|
so it sets the default using the "?=" operator, or
|
|
you can alternatively force the value on the
|
|
<filename>make</filename> command line.
|
|
To force the value on the command line, add the
|
|
variable setting to
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OEMAKE'><filename>EXTRA_OEMAKE</filename></ulink>
|
|
within the recipe as follows:
|
|
<literallayout class='monospaced'>
|
|
EXTRA_OEMAKE += "'CC=${CC}' 'CXX=${CXX}'"
|
|
</literallayout>
|
|
In the above example, single quotes are used around the
|
|
variable settings as the values are likely to contain
|
|
spaces because required default options are passed to
|
|
the compiler.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Hardcoding paths inside Makefiles is often problematic
|
|
in a cross-compilation environment.
|
|
This is particularly true because those hardcoded paths
|
|
often point to locations on the build host and thus
|
|
will either be read-only or will introduce
|
|
contamination into the cross-compilation by virtue of
|
|
being specific to the build host rather than the target.
|
|
Patching the Makefile to use prefix variables or other
|
|
path variables is usually the way to handle this.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Sometimes a Makefile runs target-specific commands such
|
|
as <filename>ldconfig</filename>.
|
|
For such cases, you might be able to simply apply
|
|
patches that remove these commands from the Makefile.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-adding-native-tools'>
|
|
<title>Adding Native Tools</title>
|
|
|
|
<para>
|
|
Often, you need to build additional tools that run on the
|
|
build host system as opposed to the target.
|
|
You should indicate this using one of the following methods
|
|
when you run <filename>devtool add</filename>:
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
Specify the name of the recipe such that it ends
|
|
with "-native".
|
|
Specifying the name like this produces a recipe that
|
|
only builds for the build host.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Specify the "‐‐also-native" option with the
|
|
<filename>devtool add</filename> command.
|
|
Specifying this option creates a recipe file that still
|
|
builds for the target but also creates a variant with
|
|
a "-native" suffix that builds for the build host.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
<note>
|
|
If you need to add a tool that is shipped as part of a
|
|
source tree that builds code for the target, you can
|
|
typically accomplish this by building the native and target
|
|
parts separately rather than within the same compilation
|
|
process.
|
|
Realize though that with the "‐‐also-native" option, you
|
|
can add the tool using just one recipe file.
|
|
</note>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-adding-node-js-modules'>
|
|
<title>Adding <filename>Node.js</filename> Modules</title>
|
|
|
|
<para>
|
|
You can use the <filename>devtool add</filename> command in the
|
|
following form to add <filename>Node.js</filename> modules:
|
|
<literallayout class='monospaced'>
|
|
$ devtool add "npm://registry.npmjs.org;name=forever;version=0.15.1"
|
|
</literallayout>
|
|
The name and version parameters are mandatory.
|
|
Lockdown and shrinkwrap files are generated and pointed to by
|
|
the recipe in order to freeze the version that is fetched for
|
|
the dependencies according to the first time.
|
|
This also saves checksums that are verified on future fetches.
|
|
Together, these behaviors ensure the reproducibility and
|
|
integrity of the build.
|
|
<note><title>Notes</title>
|
|
<itemizedlist>
|
|
<listitem><para>
|
|
You must use quotes around the URL.
|
|
The <filename>devtool add</filename> does not require
|
|
the quotes, but the shell considers ";" as a splitter
|
|
between multiple commands.
|
|
Thus, <filename>devtool add</filename> does not receive
|
|
the other parts resulting in several "command not found"
|
|
errors.
|
|
</para></listitem>
|
|
<listitem><para>
|
|
In order to support adding
|
|
<filename>Node.js</filename> modules, a
|
|
<filename>nodejs</filename> recipe must be part of your
|
|
SDK in order to provide <filename>Node.js</filename>
|
|
itself.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</note>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
<section id='sdk-working-with-recipes'>
|
|
<title>Working With Recipes</title>
|
|
|
|
<para>
|
|
When building a recipe with <filename>devtool build</filename> the
|
|
typical workflow is as follows:
|
|
<orderedlist>
|
|
<listitem><para>
|
|
Fetch the source
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Unpack the source
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Configure the source
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Compiling the source
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Install the build output
|
|
</para></listitem>
|
|
<listitem><para>
|
|
Package the installed output
|
|
</para></listitem>
|
|
</orderedlist>
|
|
For recipes in the workspace, fetching and unpacking is disabled
|
|
as the source tree has already been prepared and is persistent.
|
|
Each of these build steps is defined as a function, usually with a
|
|
"do_" prefix.
|
|
These functions are typically shell scripts but can instead be written
|
|
in Python.
|
|
</para>
|
|
|
|
<para>
|
|
If you look at the contents of a recipe, you will see that the
|
|
recipe does not include complete instructions for building the
|
|
software.
|
|
Instead, common functionality is encapsulated in classes inherited
|
|
with the <filename>inherit</filename> directive, leaving the recipe
|
|
to describe just the things that are specific to the software to be
|
|
built.
|
|
A <ulink url='ref-classes-base'><filename>base</filename></ulink>
|
|
class exists that is implicitly inherited by all recipes and provides
|
|
the functionality that most typical recipes need.
|
|
</para>
|
|
|
|
<para>
|
|
The remainder of this section presents information useful when
|
|
working with recipes.
|
|
</para>
|
|
|
|
<section id='sdk-finding-logs-and-work-files'>
|
|
<title>Finding Logs and Work Files</title>
|
|
|
|
<para>
|
|
When you are debugging a recipe that you previously created using
|
|
<filename>devtool add</filename> or whose source you are modifying
|
|
by using the <filename>devtool modify</filename> command, after
|
|
the first run of <filename>devtool build</filename>, you will
|
|
find some symbolic links created within the source tree:
|
|
<filename>oe-logs</filename>, which points to the directory in
|
|
which log files and run scripts for each build step are created
|
|
and <filename>oe-workdir</filename>, which points to the temporary
|
|
work area for the recipe.
|
|
You can use these links to get more information on what is
|
|
happening at each build step.
|
|
</para>
|
|
|
|
<para>
|
|
These locations under <filename>oe-workdir</filename> are
|
|
particularly useful:
|
|
<itemizedlist>
|
|
<listitem><para><filename>image/</filename>:
|
|
Contains all of the files installed at the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;ref-tasks-install'><filename>do_install</filename></ulink>
|
|
stage.
|
|
Within a recipe, this directory is referred to by the
|
|
expression
|
|
<filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>.
|
|
</para></listitem>
|
|
<listitem><para><filename>sysroot-destdir/</filename>:
|
|
Contains a subset of files installed within
|
|
<filename>do_install</filename> that have been put into the
|
|
shared sysroot.
|
|
For more information, see the
|
|
"<link linkend='sdk-sharing-files-between-recipes'>Sharing Files Between Recipes</link>"
|
|
section.
|
|
</para></listitem>
|
|
<listitem><para><filename>packages-split/</filename>:
|
|
Contains subdirectories for each package produced by the
|
|
recipe. (more on "Packaging" below)
|
|
For more information, see the
|
|
"<link linkend='sdk-packaging'>Packaging</link>" section.
|
|
</para></listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-setting-configure-arguments'>
|
|
<title>Setting Configure Arguments</title>
|
|
|
|
<para>
|
|
If the software your recipe is building uses GNU autoconf,
|
|
then a fixed set of arguments is passed to it to enable
|
|
cross-compilation plus any extras specified by
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OECONF'><filename>EXTRA_OECONF</filename></ulink>
|
|
set within the recipe.
|
|
If you wish to pass additional options, add them to
|
|
<filename>EXTRA_OECONF</filename>.
|
|
Other supported build tools have similar variables
|
|
(e.g.
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OECMAKE'><filename>EXTRA_OECMAKE</filename></ulink>
|
|
for CMake,
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-EXTRA_OESCONS'><filename>EXTRA_OESCONS</filename></ulink>
|
|
for <filename>Scons</filename>, and so forth).
|
|
If you need to pass anything on the <filename>make</filename>
|
|
command line, you can use <filename>EXTRA_OEMAKE</filename> to do
|
|
so.
|
|
</para>
|
|
|
|
<para>
|
|
You can use the <filename>devtool configure-help</filename> command
|
|
to help you set the arguments listed in the previous paragraph.
|
|
The command determines the exact options being passed, and shows
|
|
them to you along with any custom arguments specified through
|
|
<filename>EXTRA_OECONF</filename>.
|
|
If applicable, the command also shows you the output of the
|
|
configure script's "‐‐help" option as a reference.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-sharing-files-between-recipes'>
|
|
<title>Sharing Files Between Recipes</title>
|
|
|
|
<para>
|
|
Recipes often need to use files provided by other recipes on
|
|
the build host.
|
|
For example, an application linking to a common library needs
|
|
access to the library itself and its associated headers.
|
|
The way this access is accomplished within the extensible SDK is
|
|
through the sysroot.
|
|
One sysroot exists per "machine" for which the SDK is being built.
|
|
In practical terms, this means a sysroot exists for the target
|
|
machine, and a sysroot exists for the build host.
|
|
</para>
|
|
|
|
<para>
|
|
Recipes should never write files directly into the sysroot.
|
|
Instead, files should be installed into standard locations
|
|
during the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
|
|
task within the
|
|
<filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-D'><filename>D</filename></ulink><filename>}</filename>
|
|
directory.
|
|
A subset of these files automatically go into the sysroot.
|
|
The reason for this limitation is that almost all files that go
|
|
into the sysroot are cataloged in manifests in order to ensure
|
|
they can be removed later when a a recipe is modified or removed.
|
|
Thus, the sysroot is able to remain free from stale files.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-packaging'>
|
|
<title>Packaging</title>
|
|
|
|
<para>
|
|
Packaging is not always particularly relevant within the
|
|
extensible SDK.
|
|
However, if you examine build output gets into the final image on
|
|
the target device, it is important to understand packaging
|
|
because the contents of the image are expressed in terms of
|
|
packages ... not recipes.
|
|
</para>
|
|
|
|
<para>
|
|
During the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>
|
|
task, files installed during the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-install'><filename>do_install</filename></ulink>
|
|
task are split into one main package, which is almost always named
|
|
the same as the recipe, and several other packages.
|
|
This separation is done because not all of those installed files
|
|
are always useful in every image.
|
|
For example, you probably do not need any of the documentation
|
|
installed in a production image.
|
|
Consequently, for each recipe the documentation files are separated
|
|
into a <filename>-doc</filename> package.
|
|
Recipes that package software that has optional modules or
|
|
plugins might do additional package splitting as well.
|
|
</para>
|
|
|
|
<para>
|
|
After building a recipe you can see where files have gone by
|
|
looking in the <filename>oe-workdir/packages-split</filename>
|
|
directory, which contains a subdirectory for each package.
|
|
Apart from some advanced cases, the
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-PACKAGES'><filename>PACKAGES</filename></ulink>
|
|
and
|
|
<ulink url='&YOCTO_DOCS_REF_URL;#var-FILES'><filename>FILES</filename></ulink>
|
|
variables controls splitting.
|
|
The <filename>PACKAGES</filename> variable lists all of the
|
|
packages to be produced, while the <filename>FILES</filename>
|
|
variable specifies which files to include in each package,
|
|
using an override to specify the package.
|
|
For example, <filename>FILES_${PN}</filename> specifies the files
|
|
to go into the main package (i.e. the main package is named the
|
|
same as the recipe and
|
|
<filename>${</filename><ulink url='&YOCTO_DOCS_REF_URL;#var-PN'><filename>PN</filename></ulink><filename>}</filename>
|
|
evaluates to the recipe name).
|
|
The order of the <filename>PACKAGES</filename> value is significant.
|
|
For each installed file, the first package whose
|
|
<filename>FILES</filename> value matches the file is the package
|
|
into which the file goes.
|
|
Defaults exist for both the <filename>PACKAGES</filename> and
|
|
<filename>FILES</filename> variables.
|
|
Consequently, you might find you do not even need to set these
|
|
variables in your recipe unless the software the recipe is
|
|
building installs files into non-standard locations.
|
|
</para>
|
|
</section>
|
|
|
|
<section id='sdk-restoring-the-target-device-to-its-original-state'>
|
|
<title>Restoring the Target Device to its Original State</title>
|
|
|
|
<para>
|
|
If you use the <filename>devtool deploy-target</filename>
|
|
command to write a recipe's build output to the target, and
|
|
you are working on an existing component of the system, then you
|
|
might find yourself in a situation where you need to restore the
|
|
original files that existed prior to running the
|
|
<filename>devtool deploy-target</filename> command.
|
|
Because the <filename>devtool deploy-target</filename> command
|
|
backs up any files it overwrites, you can use the
|
|
<filename>devtool undeploy-target</filename> to restore those files
|
|
and remove any other files the recipe deployed.
|
|
Consider the following example:
|
|
<literallayout class='monospaced'>
|
|
$ devtool undeploy-target lighttpd root@192.168.7.2
|
|
</literallayout>
|
|
If you have deployed multiple applications, you can remove them
|
|
all at once thus restoring the target device back to its
|
|
original state:
|
|
<literallayout class='monospaced'>
|
|
$ devtool undeploy-target -a root@192.168.7.2
|
|
</literallayout>
|
|
Information about files deployed to the target as well as any
|
|
backed up files are stored on the target itself.
|
|
This storage of course requires some additional space
|
|
on the target machine.
|
|
<note>
|
|
The <filename>devtool deploy-target</filename> and
|
|
<filename>devtool undeploy-target</filename> command do not
|
|
currently interact with any package management system on the
|
|
target device (e.g. RPM or OPKG).
|
|
Consequently, you should not intermingle operations
|
|
<filename>devtool deploy-target</filename> and the package
|
|
manager operations on the target device.
|
|
Doing so could result in a conflicting set of files.
|
|
</note>
|
|
</para>
|
|
</section>
|
|
</section>
|
|
|
|
</appendix>
|
|
<!--
|
|
vim: expandtab tw=80 ts=4
|
|
-->
|