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diff --git a/en/devices/architecture/vndk/enabling.html b/en/devices/architecture/vndk/enabling.html deleted file mode 100644 index a034135e..00000000 --- a/en/devices/architecture/vndk/enabling.html +++ /dev/null @@ -1,189 +0,0 @@ -<html devsite> - <head> - <title>Enabling the VNDK</title> - <meta name="project_path" value="/_project.yaml" /> - <meta name="book_path" value="/_book.yaml" /> - </head> - <body> - <!-- - Copyright 2018 The Android Open Source Project - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. - --> - -<p>The VNDK requires several changes to a codebase to separate concerns between -vendor and system. Use the following guide to enable VNDK in a vendor/OEM -codebase.</p> - -<h2 id=build-system-libraries>Build system libraries</h2> -<p>The build system contains several types of objects including libraries -(shared, static, or header) and binaries:</p> - -<img src="../images/treble_vndk_build_system_libraries.png"> -<figcaption><strong>Figure 1.</strong> Build system libraries.</figcaption> - -<ul> -<li><strong>core</strong>. Used by the system image, on the system image. These -libraries cannot be used by <code>vendor</code>, <code>vendor_available</code>, -<code>vndk</code>, or <code>vndk-sp</code> libraries. -<pre class="prettyprint"> -cc_library { - name: "libThatIsCore", - ... -} -</pre> -</li> - -<li><strong>vendor-only</strong> (or <code>proprietary</code>). Used by the -vendor image, on the vendor image. -<pre class="prettyprint"> -cc_library { - name: "libThatIsVendorOnly", - proprietary: true, - # or: vendor: true, # (for things in AOSP) - ... -} -</dpre> -</li> - -<li><strong>vendor_available</strong>. Used by the vendor image, on the vendor -image (may contain duplicates of <code>core</code>). -<pre class="prettyprint"> -cc_library { - name: "libThatIsVendorAvailable", - vendor_available: true, - ... -} -</pre> -</li> - -<li><strong>vndk</strong>. Used by the vendor image, on the system image (a -subset of <code>vendor_available</code>). -<pre class="prettyprint"> -cc_library { - name: "libThatIsVndk", - vendor_available: true, - vndk: { - enabled: true, - } - ... -} -</pre> -</li> - -<li><strong>vndk-sp</strong>. Used by the system image indirectly, on the -system image (subset of <code>core</code>). -<pre class="prettyprint"> -cc_library { - name: "libThatIsVndkSp", - vendor_available: true, - vndk: { - enabled: true, - support_system_process: true, - } - ... -} -</pre> -</li> - -<li><strong>llndk</strong>. Used by both the system and vendor images. -<pre class="prettyprint"> -llndk_library { - name: "libThasIsLlndk", -} -</pre> -</li> -</ul> - -<p>When a lib is marked as <code>vendor_available:true</code>, it is built -twice:</p> -<ul> -<li>Once for platform (and thus installed to <code>/system/lib</code>).</li> -<li>Once for vendor (and thus installed to <code>/vendor/lib</code>, -<code>/system/lib/vndk</code>, or <code>/system/lib/vndk-sp</code>).</li> -</ul> - -<p>The vendor versions of libs are built with <code>-D__ANDROID_VNDK__</code>. -Private system components that may change significantly in future versions of -Android are disabled with this flag. In addition, different libraries export a -different set of headers (such as <code>liblog</code>). Options specific to a -vendor variant of a target can be specified in an <code>Android.bp</code> file -in:</p> -<pre class="prettyprint">target: { vendor: { … } }</pre> - -<h2 id=enabling>Enabling VNDK for a codebase</h2> -<p>To enable the VNDK for a codebase:</p> -<ol> -<li>Determine eligibility by calculating the required sizes of -<code>vendor.img</code> and <code>system.img</code> partitions.</li> -<li>Enable <code>BOARD_VNDK_VERSION=current</code>. You can add to -<code>BoardConfig.mk</code> or build components with it directly (i.e. -<code>m -j BOARD_VNDK_VERSION=current <var>MY-LIB</var></code>).</li> -</ol> -<p>After enabling <code>BOARD_VNDK_VERSION=current</code>, the build system -enforces the following dependency and header requirements.</p> - -<h3 id=managing-dependencies>Managing dependencies</h3> -<p>A <code>vendor</code> object that depends on a <code>core</code> component -that doesn't exist in the <code>vndk</code> or as a <code>vendor</code> object -must be resolved using one of the following options:</p> -<ul> -<li>The dependency can be removed.</li> -<li>If the <code>core</code> component is owned by <code>vendor</code>, it can -be marked as <code>vendor_available</code> or <code>vendor</code>.</li> -<li>A change making the core object part of the <code>vndk</code> may be -upstreamed to Google.</li> -</ul> -<p>In addition, if a <code>core</code> component has dependencies on a -<code>vendor</code> component, the <code>vendor</code> component must be made -into a <code>core</code> component <strong>or</strong> the dependency must be -removed in another way (for example, by removing the dependency or by moving the -dependency into a <code>vendor</code> component).</p> - -<h3 id=managing-headers>Managing headers</h3> -<p>Global header dependencies must be removed to enable the build system to know -whether to build the headers with or without <code>-D__ANDROID_VNDK__</code>. -For example, libutils headers such as <code>utils/StrongPointer.h</code> can -still be accessed using the header library -<a href="https://android.googlesource.com/platform/system/core/+/master/libutils/include/utils" class="external"><code>libutils_headers</code></a>. -</p> - -<p>Some headers (such as <code>unistd.h</code>) can no longer be transitively -included but can be included locally.</p> - -<p>Finally, the public part of <code>private/android_filesystem_config.h</code> -has been moved to <code>cutils/android_filesystem_config.h</code>. To manage -these headers, do one of the following:</p> - -<ul> -<li>Remove the dependency to -<code>private/android_filesystem_config.h</code> by replacing all -<code>AID_*</code> macros with -<code><a href="http://man7.org/linux/man-pages/man3/getgrnam.3.html" class="external">getgrnam</code></a>/<code><a href="http://man7.org/linux/man-pages/man3/getpwnam.3.html" class="external">getpwnam</code></a> -calls if possible. For example: - -<ul> -<li><code>(uid_t)AID_WIFI</code> becomes -<code>getpwnam("wifi")->pw_uid</code>.</li> -<li><code>(gid_t)AID_SDCARD_R</code> becomes -<code>getgrnam("sdcard_r")->gr_gid</code>.</li> -</ul> -For details, refer to -<code><a href="https://android.googlesource.com/platform/system/core/+/master/libcutils/include/private/android_filesystem_config.h" class="external">private/android_filesystem_config.h</code></a>. -</li> -<li>For hard-coded AIS, include -<code>cutils/android_filesystem_config.h</code>.</li> -</ul> - - </body> - </html> |