One has to do with the weird names the build system creates based on DESTDIR and other variables. The other has to do with -native recipes not buiding correctly. (From yocto-docs rev: 32a444a258e3c7c87fdc015475f54e5b34628246) Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
797 lines
35 KiB
XML
797 lines
35 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; ] >
|
||
|
||
<chapter id='faq'>
|
||
<title>FAQ</title>
|
||
<qandaset>
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How does Poky differ from <ulink url='&OE_HOME_URL;'>OpenEmbedded</ulink>?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The term "<ulink url='&YOCTO_DOCS_DEV_URL;#poky'>Poky</ulink>"
|
||
refers to the specific reference build system that
|
||
the Yocto Project provides.
|
||
Poky is based on <ulink url='&YOCTO_DOCS_DEV_URL;#oe-core'>OE-Core</ulink>
|
||
and <ulink url='&YOCTO_DOCS_DEV_URL;#bitbake-term'>BitBake</ulink>.
|
||
Thus, the generic term used here for the build system is
|
||
the "OpenEmbedded build system."
|
||
Development in the Yocto Project using Poky is closely tied to OpenEmbedded, with
|
||
changes always being merged to OE-Core or BitBake first before being pulled back
|
||
into Poky.
|
||
This practice benefits both projects immediately.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para id='faq-not-meeting-requirements'>
|
||
My development system does not meet the
|
||
required Git, tar, and Python versions.
|
||
In particular, I do not have Python 2.7.3 or greater, or
|
||
I do have Python 3.x, which is specifically not supported by
|
||
the Yocto Project.
|
||
Can I still use the Yocto Project?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
You can get the required tools on your host development
|
||
system a couple different ways (i.e. building a tarball or
|
||
downloading a tarball).
|
||
See the
|
||
"<link linkend='required-git-tar-and-python-versions'>Required Git, tar, and Python Versions</link>"
|
||
section for steps on how to update your build tools.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How can you claim Poky / OpenEmbedded-Core is stable?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
There are three areas that help with stability;
|
||
<itemizedlist>
|
||
<listitem><para>The Yocto Project team keeps
|
||
<ulink url='&YOCTO_DOCS_DEV_URL;#oe-core'>OE-Core</ulink> small
|
||
and focused, containing around 830 recipes as opposed to the thousands
|
||
available in other OpenEmbedded community layers.
|
||
Keeping it small makes it easy to test and maintain.</para></listitem>
|
||
<listitem><para>The Yocto Project team runs manual and automated tests
|
||
using a small, fixed set of reference hardware as well as emulated
|
||
targets.</para></listitem>
|
||
<listitem><para>The Yocto Project uses an autobuilder,
|
||
which provides continuous build and integration tests.</para></listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I get support for my board added to the Yocto Project?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Support for an additional board is added by creating a
|
||
Board Support Package (BSP) layer for it.
|
||
For more information on how to create a BSP layer, see the
|
||
"<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and Creating Layers</ulink>"
|
||
section in the Yocto Project Development Manual and the
|
||
<ulink url='&YOCTO_DOCS_BSP_URL;'>Yocto Project Board Support Package (BSP) Developer's Guide</ulink>.
|
||
</para>
|
||
<para>
|
||
Usually, if the board is not completely exotic, adding support in
|
||
the Yocto Project is fairly straightforward.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
Are there any products built using the OpenEmbedded build system?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The software running on the <ulink url='http://vernier.com/labquest/'>Vernier LabQuest</ulink>
|
||
is built using the OpenEmbedded build system.
|
||
See the <ulink url='http://www.vernier.com/products/interfaces/labq/'>Vernier LabQuest</ulink>
|
||
website for more information.
|
||
There are a number of pre-production devices using the OpenEmbedded build system
|
||
and the Yocto Project team
|
||
announces them as soon as they are released.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
What does the OpenEmbedded build system produce as output?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Because you can use the same set of recipes to create output of
|
||
various formats, the output of an OpenEmbedded build depends on
|
||
how you start it.
|
||
Usually, the output is a flashable image ready for the target
|
||
device.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I add my package to the Yocto Project?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
To add a package, you need to create a BitBake recipe.
|
||
For information on how to create a BitBake recipe, see the
|
||
"<ulink url='&YOCTO_DOCS_DEV_URL;#new-recipe-writing-a-new-recipe'>Writing a New Recipe</ulink>"
|
||
in the Yocto Project Development Manual.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
Do I have to reflash my entire board with a new Yocto Project image when recompiling
|
||
a package?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The OpenEmbedded build system can build packages in various
|
||
formats such as IPK for OPKG, Debian package
|
||
(<filename>.deb</filename>), or RPM.
|
||
You can then upgrade the packages using the package tools on
|
||
the device, much like on a desktop distribution such as
|
||
Ubuntu or Fedora.
|
||
However, package management on the target is entirely optional.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
What is GNOME Mobile and what is the difference between GNOME Mobile and GNOME?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
GNOME Mobile is a subset of the <ulink url='http://www.gnome.org'>GNOME</ulink>
|
||
platform targeted at mobile and embedded devices.
|
||
The main difference between GNOME Mobile and standard GNOME is that
|
||
desktop-orientated libraries have been removed, along with deprecated libraries,
|
||
creating a much smaller footprint.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
I see the error '<filename>chmod: XXXXX new permissions are r-xrwxrwx, not r-xr-xr-x</filename>'.
|
||
What is wrong?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
You are probably running the build on an NTFS filesystem.
|
||
Use <filename>ext2</filename>, <filename>ext3</filename>, or <filename>ext4</filename> instead.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<!-- <qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I make the Yocto Project work in RHEL/CentOS?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
To get the Yocto Project working under RHEL/CentOS 5.1 you need to first
|
||
install some required packages.
|
||
The standard CentOS packages needed are:
|
||
<itemizedlist>
|
||
<listitem><para>"Development tools" (selected during installation)</para></listitem>
|
||
<listitem><para><filename>texi2html</filename></para></listitem>
|
||
<listitem><para><filename>compat-gcc-34</filename></para></listitem>
|
||
</itemizedlist>
|
||
On top of these, you need the following external packages:
|
||
<itemizedlist>
|
||
<listitem><para><filename>python-sqlite2</filename> from
|
||
<ulink url='http://dag.wieers.com/rpm/packages/python-sqlite2/'>DAG repository</ulink>
|
||
</para></listitem>
|
||
<listitem><para><filename>help2man</filename> from
|
||
<ulink url='http://centos.karan.org/el4/extras/stable/x86_64/RPMS/repodata/repoview/help2man-0-1.33.1-2.html'>Karan repository</ulink></para></listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
|
||
<para>
|
||
Once these packages are installed, the OpenEmbedded build system will be able
|
||
to build standard images.
|
||
However, there might be a problem with the QEMU emulator segfaulting.
|
||
You can either disable the generation of binary locales by setting
|
||
<filename><link linkend='var-ENABLE_BINARY_LOCALE_GENERATION'>ENABLE_BINARY_LOCALE_GENERATION</link>
|
||
</filename> to "0" or by removing the <filename>linux-2.6-execshield.patch</filename>
|
||
from the kernel and rebuilding it since that is the patch that causes the problems with QEMU.
|
||
</para>
|
||
|
||
<note>
|
||
<para>For information on distributions that the Yocto Project
|
||
uses during validation, see the
|
||
<ulink url='&YOCTO_WIKI_URL;/wiki/Distribution_Support'>Distribution Support</ulink>
|
||
Wiki page.</para>
|
||
<para>For notes about using the Yocto Project on a RHEL 4-based
|
||
host, see the
|
||
<ulink url='&YOCTO_WIKI_URL;/wiki/BuildingOnRHEL4'>Building on RHEL4</ulink>
|
||
Wiki page.</para>
|
||
</note>
|
||
</answer>
|
||
</qandaentry> -->
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
I see lots of 404 responses for files on
|
||
<filename>&YOCTO_HOME_URL;/sources/*</filename>. Is something wrong?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Nothing is wrong.
|
||
The OpenEmbedded build system checks any configured source mirrors before downloading
|
||
from the upstream sources.
|
||
The build system does this searching for both source archives and
|
||
pre-checked out versions of SCM-managed software.
|
||
These checks help in large installations because it can reduce load on the SCM servers
|
||
themselves.
|
||
The address above is one of the default mirrors configured into the
|
||
build system.
|
||
Consequently, if an upstream source disappears, the team
|
||
can place sources there so builds continue to work.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
I have machine-specific data in a package for one machine only but the package is
|
||
being marked as machine-specific in all cases, how do I prevent this?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Set <filename><link linkend='var-SRC_URI_OVERRIDES_PACKAGE_ARCH'>SRC_URI_OVERRIDES_PACKAGE_ARCH</link>
|
||
</filename> = "0" in the <filename>.bb</filename> file but make sure the package is
|
||
manually marked as
|
||
machine-specific for the case that needs it.
|
||
The code that handles
|
||
<filename>SRC_URI_OVERRIDES_PACKAGE_ARCH</filename> is in
|
||
the <filename>meta/classes/base.bbclass</filename> file.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
I'm behind a firewall and need to use a proxy server. How do I do that?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Most source fetching by the OpenEmbedded build system is done by <filename>wget</filename>
|
||
and you therefore need to specify the proxy settings in a
|
||
<filename>.wgetrc</filename> file in your home directory.
|
||
Here are some example settings:
|
||
<literallayout class='monospaced'>
|
||
http_proxy = http://proxy.yoyodyne.com:18023/
|
||
ftp_proxy = http://proxy.yoyodyne.com:18023/
|
||
</literallayout>
|
||
The Yocto Project also includes a
|
||
<filename>site.conf.sample</filename> file that shows how to
|
||
configure CVS and Git proxy servers if needed.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
What’s the difference between <filename>foo</filename> and <filename>foo-native</filename>?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The <filename>*-native</filename> targets are designed to run on the system
|
||
being used for the build.
|
||
These are usually tools that are needed to assist the build in some way such as
|
||
<filename>quilt-native</filename>, which is used to apply patches.
|
||
The non-native version is the one that runs on the target device.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
I'm seeing random build failures. Help?!
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
If the same build is failing in totally different and random
|
||
ways, the most likely explanation is:
|
||
<itemizedlist>
|
||
<listitem><para>The hardware you are running the build on
|
||
has some problem.</para></listitem>
|
||
<listitem><para>You are running the build under
|
||
virtualization, in which case the virtualization
|
||
probably has bugs.</para></listitem>
|
||
</itemizedlist>
|
||
The OpenEmbedded build system processes a massive amount of
|
||
data that causes lots of network, disk and CPU activity and
|
||
is sensitive to even single-bit failures in any of these areas.
|
||
True random failures have always been traced back to hardware
|
||
or virtualization issues.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
What do we need to ship for license compliance?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
This is a difficult question and you need to consult your lawyer
|
||
for the answer for your specific case.
|
||
It is worth bearing in mind that for GPL compliance, there needs
|
||
to be enough information shipped to allow someone else to
|
||
rebuild and produce the same end result you are shipping.
|
||
This means sharing the source code, any patches applied to it,
|
||
and also any configuration information about how that package
|
||
was configured and built.
|
||
</para>
|
||
|
||
<para>
|
||
You can find more information on licensing in the
|
||
"<ulink url='&YOCTO_DOCS_DEV_URL;#licensing'>Licensing</ulink>"
|
||
and "<ulink url='&YOCTO_DOCS_DEV_URL;#maintaining-open-source-license-compliance-during-your-products-lifecycle'>Maintaining Open Source License Compliance During Your Product's Lifecycle</ulink>"
|
||
sections, both of which are in the Yocto Project Development
|
||
Manual.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I disable the cursor on my touchscreen device?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
You need to create a form factor file as described in the
|
||
"<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout-misc-recipes'>Miscellaneous BSP-Specific Recipe Files</ulink>"
|
||
section in the Yocto Project Board Support Packages (BSP)
|
||
Developer's Guide.
|
||
Set the <filename>HAVE_TOUCHSCREEN</filename> variable equal to
|
||
one as follows:
|
||
<literallayout class='monospaced'>
|
||
HAVE_TOUCHSCREEN=1
|
||
</literallayout>
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I make sure connected network interfaces are brought up by default?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The default interfaces file provided by the netbase recipe does not
|
||
automatically bring up network interfaces.
|
||
Therefore, you will need to add a BSP-specific netbase that includes an interfaces
|
||
file.
|
||
See the "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout-misc-recipes'>Miscellaneous BSP-Specific Recipe Files</ulink>"
|
||
section in the Yocto Project Board Support Packages (BSP)
|
||
Developer's Guide for information on creating these types of
|
||
miscellaneous recipe files.
|
||
</para>
|
||
<para>
|
||
For example, add the following files to your layer:
|
||
<literallayout class='monospaced'>
|
||
meta-MACHINE/recipes-bsp/netbase/netbase/MACHINE/interfaces
|
||
meta-MACHINE/recipes-bsp/netbase/netbase_5.0.bbappend
|
||
</literallayout>
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I create images with more free space?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
By default, the OpenEmbedded build system creates images
|
||
that are 1.3 times the size of the populated root filesystem.
|
||
To affect the image size, you need to set various
|
||
configurations:
|
||
<itemizedlist>
|
||
<listitem><para><emphasis>Image Size:</emphasis>
|
||
The OpenEmbedded build system uses the
|
||
<link linkend='var-IMAGE_ROOTFS_SIZE'><filename>IMAGE_ROOTFS_SIZE</filename></link>
|
||
variable to define the size of the image in Kbytes.
|
||
The build system determines the size by taking into
|
||
account the initial root filesystem size before any
|
||
modifications such as requested size for the image and
|
||
any requested additional free disk space to be
|
||
added to the image.</para></listitem>
|
||
<listitem><para><emphasis>Overhead:</emphasis>
|
||
Use the
|
||
<link linkend='var-IMAGE_OVERHEAD_FACTOR'><filename>IMAGE_OVERHEAD_FACTOR</filename></link>
|
||
variable to define the multiplier that the build system
|
||
applies to the initial image size, which is 1.3 by
|
||
default.</para></listitem>
|
||
<listitem><para><emphasis>Additional Free Space:</emphasis>
|
||
Use the
|
||
<link linkend='var-IMAGE_ROOTFS_EXTRA_SPACE'><filename>IMAGE_ROOTFS_EXTRA_SPACE</filename></link>
|
||
variable to add additional free space to the image.
|
||
The build system adds this space to the image after
|
||
it determines its
|
||
<filename>IMAGE_ROOTFS_SIZE</filename>.
|
||
</para></listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
Why don't you support directories with spaces in the pathnames?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The Yocto Project team has tried to do this before but too
|
||
many of the tools the OpenEmbedded build system depends on,
|
||
such as <filename>autoconf</filename>, break when they find
|
||
spaces in pathnames.
|
||
Until that situation changes, the team will not support spaces
|
||
in pathnames.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
How do I use an external toolchain?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The toolchain configuration is very flexible and customizable.
|
||
It is primarily controlled with the
|
||
<filename><link linkend='var-TCMODE'>TCMODE</link></filename>
|
||
variable.
|
||
This variable controls which <filename>tcmode-*.inc</filename>
|
||
file to include from the
|
||
<filename>meta/conf/distro/include</filename> directory within
|
||
the
|
||
<ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
|
||
</para>
|
||
|
||
<para>
|
||
The default value of <filename>TCMODE</filename> is "default",
|
||
which tells the OpenEmbedded build system to use its internally
|
||
built toolchain (i.e. <filename>tcmode-default.inc</filename>).
|
||
However, other patterns are accepted.
|
||
In particular, "external-*" refers to external toolchains.
|
||
One example is the Sourcery G++ Toolchain.
|
||
The support for this toolchain resides in the separate
|
||
<filename>meta-sourcery</filename> layer at
|
||
<ulink url='http://github.com/MentorEmbedded/meta-sourcery/'></ulink>.
|
||
</para>
|
||
|
||
<para>
|
||
In addition to the toolchain configuration, you also need a
|
||
corresponding toolchain recipe file.
|
||
This recipe file needs to package up any pre-built objects in
|
||
the toolchain such as <filename>libgcc</filename>,
|
||
<filename>libstdcc++</filename>, any locales, and
|
||
<filename>libc</filename>.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para id='how-does-the-yocto-project-obtain-source-code-and-will-it-work-behind-my-firewall-or-proxy-server'>
|
||
How does the OpenEmbedded build system obtain source code and
|
||
will it work behind my firewall or proxy server?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
The way the build system obtains source code is highly
|
||
configurable.
|
||
You can setup the build system to get source code in most
|
||
environments if HTTP transport is available.
|
||
</para>
|
||
<para>
|
||
When the build system searches for source code, it first
|
||
tries the local download directory.
|
||
If that location fails, Poky tries
|
||
<link linkend='var-PREMIRRORS'><filename>PREMIRRORS</filename></link>,
|
||
the upstream source, and then
|
||
<link linkend='var-MIRRORS'><filename>MIRRORS</filename></link>
|
||
in that order.
|
||
</para>
|
||
<para>
|
||
Assuming your distribution is "poky", the OpenEmbedded build
|
||
system uses the Yocto Project source
|
||
<filename>PREMIRRORS</filename> by default for SCM-based
|
||
sources, upstreams for normal tarballs, and then falls back
|
||
to a number of other mirrors including the Yocto Project
|
||
source mirror if those fail.
|
||
</para>
|
||
<para>
|
||
As an example, you could add a specific server for the
|
||
build system to attempt before any others by adding something
|
||
like the following to the <filename>local.conf</filename>
|
||
configuration file:
|
||
<literallayout class='monospaced'>
|
||
PREMIRRORS_prepend = "\
|
||
git://.*/.* http://www.yoctoproject.org/sources/ \n \
|
||
ftp://.*/.* http://www.yoctoproject.org/sources/ \n \
|
||
http://.*/.* http://www.yoctoproject.org/sources/ \n \
|
||
https://.*/.* http://www.yoctoproject.org/sources/ \n"
|
||
</literallayout>
|
||
</para>
|
||
<para>
|
||
These changes cause the build system to intercept Git, FTP,
|
||
HTTP, and HTTPS requests and direct them to the
|
||
<filename>http://</filename> sources mirror.
|
||
You can use <filename>file://</filename> URLs to point to
|
||
local directories or network shares as well.
|
||
</para>
|
||
<para>
|
||
Aside from the previous technique, these options also exist:
|
||
<literallayout class='monospaced'>
|
||
BB_NO_NETWORK = "1"
|
||
</literallayout>
|
||
This statement tells BitBake to issue an error instead of
|
||
trying to access the Internet.
|
||
This technique is useful if you want to ensure code builds
|
||
only from local sources.
|
||
</para>
|
||
<para>
|
||
Here is another technique:
|
||
<literallayout class='monospaced'>
|
||
BB_FETCH_PREMIRRORONLY = "1"
|
||
</literallayout>
|
||
This statement limits the build system to pulling source
|
||
from the <filename>PREMIRRORS</filename> only.
|
||
Again, this technique is useful for reproducing builds.
|
||
</para>
|
||
<para>
|
||
Here is another technique:
|
||
<literallayout class='monospaced'>
|
||
BB_GENERATE_MIRROR_TARBALLS = "1"
|
||
</literallayout>
|
||
This statement tells the build system to generate mirror
|
||
tarballs.
|
||
This technique is useful if you want to create a mirror server.
|
||
If not, however, the technique can simply waste time during
|
||
the build.
|
||
</para>
|
||
<para>
|
||
Finally, consider an example where you are behind an
|
||
HTTP-only firewall.
|
||
You could make the following changes to the
|
||
<filename>local.conf</filename> configuration file as long as
|
||
the <filename>PREMIRRORS</filename> server is current:
|
||
<literallayout class='monospaced'>
|
||
PREMIRRORS_prepend = "\
|
||
ftp://.*/.* http://www.yoctoproject.org/sources/ \n \
|
||
http://.*/.* http://www.yoctoproject.org/sources/ \n \
|
||
https://.*/.* http://www.yoctoproject.org/sources/ \n"
|
||
BB_FETCH_PREMIRRORONLY = "1"
|
||
</literallayout>
|
||
These changes would cause the build system to successfully
|
||
fetch source over HTTP and any network accesses to anything
|
||
other than the <filename>PREMIRRORS</filename> would fail.
|
||
</para>
|
||
<para>
|
||
The build system also honors the standard shell environment
|
||
variables <filename>http_proxy</filename>,
|
||
<filename>ftp_proxy</filename>,
|
||
<filename>https_proxy</filename>, and
|
||
<filename>all_proxy</filename> to redirect requests through
|
||
proxy servers.
|
||
</para>
|
||
<note>
|
||
You can find more information on the
|
||
"<ulink url='&YOCTO_WIKI_URL;/wiki/Working_Behind_a_Network_Proxy'>Working Behind a Network Proxy</ulink>"
|
||
Wiki page.
|
||
</note>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
Can I get rid of build output so I can start over?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Yes - you can easily do this.
|
||
When you use BitBake to build an image, all the build output
|
||
goes into the directory created when you run the
|
||
build environment setup script (i.e.
|
||
<link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>
|
||
or
|
||
<link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>).
|
||
By default, this <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
|
||
is named <filename>build</filename> but can be named
|
||
anything you want.
|
||
</para>
|
||
|
||
<para>
|
||
Within the Build Directory, is the <filename>tmp</filename>
|
||
directory.
|
||
To remove all the build output yet preserve any source code or
|
||
downloaded files from previous builds, simply remove the
|
||
<filename>tmp</filename> directory.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
Why do <filename>${bindir}</filename> and <filename>${libdir}</filename> have strange values for <filename>-native</filename> recipes?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
Executables and libraries might need to be used from a
|
||
directory other than the directory into which they were
|
||
initially installed.
|
||
Complicating this situation is the fact that sometimes these
|
||
executables and libraries are compiled with the expectation
|
||
of being run from that initial installation target directory.
|
||
If this is the case, moving them causes problems.
|
||
</para>
|
||
|
||
<para>
|
||
This scenario is a fundamental problem for package maintainers
|
||
of mainstream Linux distributions as well as for the
|
||
OpenEmbedded build system.
|
||
As such, a well-established solution exists.
|
||
Makefiles, Autotools configuration scripts, and other build
|
||
systems are expected to respect environment variables such as
|
||
<filename>bindir</filename>, <filename>libdir</filename>,
|
||
and <filename>sysconfdir</filename> that indicate where
|
||
executables, libraries, and data reside when a program is
|
||
actually run.
|
||
And, they are also expected to respect a
|
||
<filename>DESTDIR</filename> environment variable, which is
|
||
prepended to all the other variables when the build system
|
||
actually installs the files.
|
||
It is understood that the program does not actually run from
|
||
within <filename>DESTDIR</filename>.
|
||
</para>
|
||
|
||
<para>
|
||
When the OpenEmbedded build system uses a recipe to build a
|
||
target-architecture program (i.e. one that is intended for
|
||
inclusion on the image being built), that program eventually
|
||
runs from the root file system of that image.
|
||
Thus, the build system provides a value of "/usr/bin" for
|
||
<filename>bindir</filename>, a value of "/usr/lib" for
|
||
<filename>libdir</filename>, and so forth.
|
||
</para>
|
||
|
||
<para>
|
||
Meanwhile, <filename>DESTDIR</filename> is a path within the
|
||
<ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>.
|
||
However, when the recipe builds a native program (i.e. one
|
||
that is intended to run on the build machine), that program
|
||
is never installed directly to the build machine's root
|
||
file system.
|
||
Consequently, the build system uses paths within the Build
|
||
Directory for <filename>DESTDIR</filename>,
|
||
<filename>bindir</filename> and related variables.
|
||
To better understand this, consider the following two paths
|
||
where the first is relatively normal and the second is not:
|
||
<note>
|
||
Due to these lengthy examples, the paths are artificially
|
||
broke across lines for readability.
|
||
</note>
|
||
<literallayout class='monospaced'>
|
||
/home/maxtothemax/poky-bootchart2/build/tmp/work/i586-poky-linux/zlib/
|
||
1.2.8-r0/sysroot-destdir/usr/bin
|
||
|
||
/home/maxtothemax/poky-bootchart2/build/tmp/work/x86_64-linux/
|
||
zlib-native/1.2.8-r0/sysroot-destdir/home/maxtothemax/poky-bootchart2/
|
||
build/tmp/sysroots/x86_64-linux/usr/bin
|
||
</literallayout>
|
||
The standard <filename>DESTDIR</filename> mechanism leaves no
|
||
other choice.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
<qandaentry>
|
||
<question>
|
||
<para>
|
||
The files provided by my <filename>-native</filename> recipe do
|
||
not appear to be available to other recipes.
|
||
Files are missing from the native sysroot, my recipe is
|
||
installing to the wrong place, or I am getting permissions
|
||
errors during the do_install task in my recipe! What is wrong?
|
||
</para>
|
||
</question>
|
||
<answer>
|
||
<para>
|
||
This situation results when the OpenEmbedded build system does
|
||
not recognize the environment variables supplied to it by
|
||
<ulink url='&YOCTO_DOCS_DEV_URL;#bitbake-term'>BitBake</ulink>.
|
||
The incident that prompted this FAQ entry involved a Makefile
|
||
that used an environment variable named
|
||
<filename>BINDIR</filename> instead of the more standard
|
||
variable <filename>bindir</filename>.
|
||
The makefile's hardcoded default value of "/usr/bin" worked
|
||
most of the time, but not for the recipe's
|
||
<filename>-native</filename> variant.
|
||
Consequently, permissions errors might be caused by a Makefile
|
||
that ignores <filename>DESTDIR</filename> or uses a different
|
||
name for that environment variable.
|
||
Check the OpenEmbedded build system to see if these kinds of
|
||
issues exist.
|
||
</para>
|
||
</answer>
|
||
</qandaentry>
|
||
|
||
</qandaset>
|
||
</chapter>
|
||
<!--
|
||
vim: expandtab tw=80 ts=4
|
||
-->
|