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overview-manual, ref-manual: Moved auto added runtime deps section
Fixes [YOCTO #12370] The "Automatically Added Runtime Dependencies" section moved from the ref-manual to the overview-manual. This topic is concepts and needs to live in the new overview-manual's concepts chapter. Fixed some links in the ref-manual and one in the dev-manual. (From yocto-docs rev: fa3e12030ce867cb81feed453d35c3a3643decd2) Signed-off-by: Scott Rifenbark <srifenbark@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
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Scott Rifenbark
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Richard Purdie
Richard Purdie
parent
00f87f8416
commit
a60d9e2917
@@ -1106,6 +1106,153 @@
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</section>
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</section>
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<section id='automatically-added-runtime-dependencies'>
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<title>Automatically Added Runtime Dependencies</title>
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<para>
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The OpenEmbedded build system automatically adds common types of
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runtime dependencies between packages, which means that you do not
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need to explicitly declare the packages using
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<ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>.
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Three automatic mechanisms exist (<filename>shlibdeps</filename>,
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<filename>pcdeps</filename>, and <filename>depchains</filename>)
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that handle shared libraries, package configuration (pkg-config)
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modules, and <filename>-dev</filename> and
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<filename>-dbg</filename> packages, respectively.
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For other types of runtime dependencies, you must manually declare
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the dependencies.
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<itemizedlist>
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<listitem><para>
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<filename>shlibdeps</filename>:
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During the
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<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>
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task of each recipe, all shared libraries installed by the
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recipe are located.
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For each shared library, the package that contains the
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shared library is registered as providing the shared
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library.
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More specifically, the package is registered as providing
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the
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<ulink url='https://en.wikipedia.org/wiki/Soname'>soname</ulink>
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of the library.
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The resulting shared-library-to-package mapping
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is saved globally in
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<ulink url='&YOCTO_DOCS_REF_URL;#var-PKGDATA_DIR'><filename>PKGDATA_DIR</filename></ulink>
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by the
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<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-packagedata'><filename>do_packagedata</filename></ulink>
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task.</para>
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<para>Simultaneously, all executables and shared libraries
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installed by the recipe are inspected to see what shared
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libraries they link against.
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For each shared library dependency that is found,
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<filename>PKGDATA_DIR</filename> is queried to
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see if some package (likely from a different recipe)
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contains the shared library.
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If such a package is found, a runtime dependency is added
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from the package that depends on the shared library to the
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package that contains the library.</para>
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<para>The automatically added runtime dependency also
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includes a version restriction.
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This version restriction specifies that at least the
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current version of the package that provides the shared
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library must be used, as if
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"<replaceable>package</replaceable> (>= <replaceable>version</replaceable>)"
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had been added to
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<ulink url='&YOCTO_DOCS_REF_URL;#var-RDEPENDS'><filename>RDEPENDS</filename></ulink>.
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This forces an upgrade of the package containing the shared
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library when installing the package that depends on the
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library, if needed.</para>
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<para>If you want to avoid a package being registered as
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providing a particular shared library (e.g. because the library
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is for internal use only), then add the library to
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<ulink url='&YOCTO_DOCS_REF_URL;#var-PRIVATE_LIBS'><filename>PRIVATE_LIBS</filename></ulink>
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inside the package's recipe.
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</para></listitem>
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<listitem><para>
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<filename>pcdeps</filename>:
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During the
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<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-package'><filename>do_package</filename></ulink>
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task of each recipe, all pkg-config modules
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(<filename>*.pc</filename> files) installed by the recipe
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are located.
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For each module, the package that contains the module is
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registered as providing the module.
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The resulting module-to-package mapping is saved globally in
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<ulink url='&YOCTO_DOCS_REF_URL;#var-PKGDATA_DIR'><filename>PKGDATA_DIR</filename></ulink>
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by the
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<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-packagedata'><filename>do_packagedata</filename></ulink>
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task.</para>
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<para>Simultaneously, all pkg-config modules installed by
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the recipe are inspected to see what other pkg-config
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modules they depend on.
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A module is seen as depending on another module if it
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contains a "Requires:" line that specifies the other module.
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For each module dependency,
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<filename>PKGDATA_DIR</filename> is queried to see if some
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package contains the module.
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If such a package is found, a runtime dependency is added
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from the package that depends on the module to the package
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that contains the module.
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<note>
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The <filename>pcdeps</filename> mechanism most often
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infers dependencies between <filename>-dev</filename>
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packages.
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</note>
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</para></listitem>
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<listitem><para>
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<filename>depchains</filename>:
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If a package <filename>foo</filename> depends on a package
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<filename>bar</filename>, then <filename>foo-dev</filename>
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and <filename>foo-dbg</filename> are also made to depend on
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<filename>bar-dev</filename> and
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<filename>bar-dbg</filename>, respectively.
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Taking the <filename>-dev</filename> packages as an
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example, the <filename>bar-dev</filename> package might
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provide headers and shared library symlinks needed by
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<filename>foo-dev</filename>, which shows the need
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for a dependency between the packages.</para>
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<para>The dependencies added by
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<filename>depchains</filename> are in the form of
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<ulink url='&YOCTO_DOCS_REF_URL;#var-RRECOMMENDS'><filename>RRECOMMENDS</filename></ulink>.
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<note>
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By default, <filename>foo-dev</filename> also has an
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<filename>RDEPENDS</filename>-style dependency on
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<filename>foo</filename>, because the default value of
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<filename>RDEPENDS_${PN}-dev</filename> (set in
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<filename>bitbake.conf</filename>) includes
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"${PN}".
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</note></para>
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<para>To ensure that the dependency chain is never broken,
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<filename>-dev</filename> and <filename>-dbg</filename>
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packages are always generated by default, even if the
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packages turn out to be empty.
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See the
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<ulink url='&YOCTO_DOCS_REF_URL;#var-ALLOW_EMPTY'><filename>ALLOW_EMPTY</filename></ulink>
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variable for more information.
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</para></listitem>
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</itemizedlist>
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</para>
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<para>
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The <filename>do_package</filename> task depends on the
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<ulink url='&YOCTO_DOCS_REF_URL;#ref-tasks-packagedata'><filename>do_packagedata</filename></ulink>
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task of each recipe in
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<ulink url='&YOCTO_DOCS_REF_URL;#var-DEPENDS'><filename>DEPENDS</filename></ulink>
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through use of a
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<filename>[</filename><ulink url='&YOCTO_DOCS_BB_URL;#variable-flags'><filename>deptask</filename></ulink><filename>]</filename>
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declaration, which guarantees that the required
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shared-library/module-to-package mapping information will be available
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when needed as long as <filename>DEPENDS</filename> has been
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correctly set.
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</para>
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</section>
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<section id='x32'>
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<title>x32 psABI</title>
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