1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
|
<html devsite>
<head>
<title>Generating VNDK Snapshots</title>
<meta name="project_path" value="/_project.yaml" />
<meta name="book_path" value="/_book.yaml" />
</head>
{% include "_versions.html" %}
<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>
A VNDK snapshot is a set of VNDK-core and VNDK-SP libs for an Android release.
You can upgrade only the system partition if the system.img includes the
corresponding VNDK snapshot needed by the vendor.img.
</p>
<aside class="note"><strong>Note:</strong> This page provides design details for
building and updating a VNDK snapshot. For details on the background,
definition, and use cases of VNDK snapshots, refer to
<a href="/devices/architecture/vndk/snapshot-design">VNDK Snapshot Design</a>.
</aside>
<p>
Official VNDK snapshots are built automatically on the Android build server
and checked into <code>/prebuilts/vndk</code> of the Android source tree. For
development purposes, you can build VNDK snapshots locally. VNDK snapshots are
supported for arm, arm64, x86, and x86_64 TARGET_ARCH flavors.
</p>
<h2 id="snapshot-build-artifacts">Snapshot build artifacts</h2>
<p>
The Android build server generates build artifacts for VNDK snapshots using
the following build parameters and build commands.
</p>
<h3 id="build-parameters">Build parameters</h3>
<p>
The build target name is <code>vndk</code> and the build target configuration
is as follows:
</p>
<ul>
<li>TARGET_PRODUCT=aosp_{TARGET_ARCH}_ab</li>
<li>TARGET_BUILD_VARIANT=user</li>
<li>TARGET_ARCH. Same as Generic System Image (GSI) target archs (arm, arm64,
x86, x86_64).</li>
<li>TARGET_ARCH_VARIANT. For snapshot v27 (Android 8.1), includes popular
configurations (listed below); future releases may include other arch/cpu
variants.</li>
</ul>
<table>
<thead>
<tr>
<th>TARGET_PRODUCT</th>
<th>TARGET_ARCH</th>
<th>TARGET_ARCH_VARIANT</th>
</tr>
</thead>
<tbody>
<tr>
<td>aosp_arm_ab</td>
<td>arm</td>
<td>armv7-a-neon</td>
</tr>
<tr>
<td>aosp_arm64_ab</td>
<td>arm64</td>
<td>armv8-a</td>
</tr>
<tr>
<td>aosp_x86_ab</td>
<td>x86</td>
<td>x86</td>
</tr>
<tr>
<td>aosp_x86_64_ab</td>
<td>x86_64</td>
<td>x86_64</td>
</tr>
</tbody>
</table>
<h3 id="build-commands">Build commands</h3>
<p>
For official snapshots, Android {{ androidPVersionNumber }} includes a new
dummy target (<code>vndk</code>) in
<a href="https://android.googlesource.com/platform/build/+/master/core/tasks/vndk.mk">vndk.mk</a>
that builds and outputs a VNDK snapshot to <code>$DIST_DIR</code>. The
snapshot zip file uses the format <code>android-vndk-{TARGET_ARCH}.zip</code>.
For example:
</p>
<pre class="prettyprint">
$ lunch aosp_<ARCH>_ab-user
$ make -j vndk dist [BOARD_VNDK_VERSION=current]
</pre>
<p>
The Android build server uses the
<a href="https://android.googlesource.com/platform/development/+/master/vndk/snapshot/build.sh">build.sh</a>
script to build all supported arch flavors with the following command:
</p>
<pre class="prettyprint">
$ DIST_DIR=%dist_dir% development/vndk/snapshot/build.sh
</pre>
<p>
VNDK snapshots for an Android Version are generated from the
<code><Android Version>-release</code> branch.
</p>
<h3 id="build-locally">Building locally</h3>
<p>
During development, you can build VNDK snapshots from a local source tree with
the following commands:
</p>
<ul>
<li>To build all supported archs at once, execute the build script
(<code>build.sh</code>):
<pre class="prettyprint">
$ cd $ANDROID_BUILD_TOP
$ development/vndk/snapshot/build.sh
</pre>
</li>
<li>To build one specific TARGET_ARCH:
<pre class="prettyprint">
$ lunch aosp_<ARCH>_ab-user
$ m -j vndk dist
</pre>
</li>
</ul>
<p>
The corresponding <code>android-vndk-<ARCH>.zip</code> file is created
under <code>$DIST_DIR</code>.
</p>
<h2 id="snapshot-files">Snapshot files</h2>
<p>
A VNDK snapshot includes the following files:
</p>
<ul>
<li>Vendor variant of VNDK-core and VNDK-SP shared libraries.
<ul>
<li>LL-NDK shared libs are not needed as they are backward compatible.</li>
<li>For 64bit targets, both TARGET_ARCH and TARGET_2ND_ARCH libraries are
built and included.</li>
</ul>
</li>
<li>List of VNDK-core, VNDK-SP, LL-NDK, and VNDK-private libraries is at
<code>[vndkcore|vndksp|llndk|vndkprivate].libraries.txt</code>.</li>
<li>Linker config file is <code>ld.config.txt</code>.</li>
<li>License files. </li>
<li><code>module_paths.txt</code>. Records the module paths for all VNDK
libraries, which is needed for checking that GPL projects have sources
released in a given Android source tree.</li>
</ul>
<p>
For a given VNDK snapshot zip file,
<code>android-vndk-{TARGET_ARCH}.zip</code>, the VNDK prebuilt libraries are
grouped in separate directories named
<code>arch-{TARGET_ARCH}-{TARGET_ARCH_VARIANT}</code> according to ABI
bitness. For example, for <code>android-vndk-arm64.zip</code>, the 64-bit libs
are placed under <code>arch-arm64-armv8-a</code> and the 32-bit libs are
placed under <code>arch-arm-armv8-a</code>.
</p>
<h3 id="example-snapshot-dir-structure">Example: VNDK snapshot directory
structure</h3>
<p>
The example below shows the directory structure for an arm64
(<code>TARGET_ARCH=arm64</code>) VNDK snapshot zip file
(<code>android-vndk-arm64.zip</code>).
</p>
<img src="/devices/architecture/images/vndk_snapshot_directory.png">
<figcaption><strong>Figure 1. </strong>VNDK snapshot directory structure
(example)</figcaption>
<h2 id='upload-vndk-snapshots'>Uploading VNDK snapshots</h2>
<p>
VNDK snapshots are checked in the source tree under
<code>/prebuilts/vndk/v<VER></code>, where <code><VER></code> is
equal to the version of the VNDK snapshot (which follows the SDK version of
the corresponding Android release). For example, the O MR1 VNDK snapshot has
version 27.
</p>
<h3 id="using-update-py">Using the update.py script</h3>
<p>
The <code>update.py</code> script
(<code>/development/vndk/snapshot/update.py)</code> automates the process of
adding a pre-built VNDK snapshot to the source tree. This script performs the
following tasks:
</p>
<ol>
<li>In <code>/prebuilts/vndk/v<VER></code>, uses <code>repo start</code>
to create new git branch.</li>
<li>Fetches and unzips VNDK snapshot build artifacts.</li>
<li>Runs <code>gen_buildfiles.py</code> to auto generate the build files
(<code>Android.mk</code>, <code>Android.bp</code>).</li>
<li>Runs <code>check_gpl_license.py</code> to verify the prebuilt libraries
licensed under the General Public License (GPL) have sources released in
current source tree.</li>
<li>Uses <code>git commit</code> to commit new changes.</li>
</ol>
<h3 id="using-local-snapshots">Using locally-built VNDK snapshots</h3>
<p>
During development, you can use locally-built VNDK snapshots for testing. When
the <code>--local</code> option is specified, <code>update.py</code> fetches
VNDK snapshot build artifacts from local <code>$DIST_DIR</code> instead of the
Android build server. Usage:
</p>
<pre class="prettyprint">
$ python update.py <VER> --local
</pre>
<p>
For example, to update the O MR1 VNDK snapshot with local build artifacts,
run:
</p>
<pre class="prettyprint">
$ python update.py 27 --local
</pre>
<p>
Because local mode is designed for testing only, the script skips the GPL
license checking and git commit steps.
</p>
<h3 id="dir-structure-prebuilts">Directory structure for prebuilts/vndk</h3>
<img src="/devices/architecture/images/vndk_snapshot_prebuilt.png">
<figcaption><strong>Figure 2. </strong>Prebuilts/vndk directory
structure</figcaption>
<h2 id="install-vndk-snapshot">Installing VNDK snapshots</h2>
<p>
The system image installs VNDK snapshot libraries at build time using the
information in <code>BOARD_VNDK_VERSION</code>,
<code>PRODUCT_EXTRA_VNDK_VERSIONS</code>, and <code>ro.vndk.version</code>.
You can control which VNDK snapshots get installed from
<code>/prebuilts/vndk/v<VER></code> using one of the following options:
</p>
<ul>
<li><strong>Option 1:</strong> <code>BOARD_VNDK_VERSION</code>. Use the
snapshot modules for building the current vendor modules and install only the
snapshot modules that are required for the vendor modules.</li>
<li><strong>Option 2:</strong> <code>PRODUCT_EXTRA_VNDK_VERSIONS</code>.
Install the VNDK snapshot modules regardless of the current vendor modules.
This installs the prebuilt VNDK snapshots listed in
<code>PRODUCT_EXTRA_VNDK_VERSIONS</code> without linking them to any other
modules at build time.</li>
</ul>
<h3 id="set-board-vndk">Setting BOARD_VNDK_VERSION</h3>
<p>
<code>BOARD_VNDK_VERSION</code> shows the VNDK version that current vendor
modules are required to build. If <code>BOARD_VNDK_VERSION</code> has an
available VNDK snapshot version in <code>/prebuilts/vndk</code> directory, the
VNDK snapshot indicated in <code>BOARD_VNDK_VERSION</code> is installed. If
the VNDK snapshot is not available in the directory, a build error occurs.
</p>
<p>
Defining <code>BOARD_VNDK_VERSION</code> also enables the VNDK modules to be
installed. Vendor modules link with the VNDK snapshot version defined in
<code>BOARD_VNDK_VERSION</code> at build time (this does not build current
VNDK modules in the system source). When downloading the full source tree from
a repository, both system and vendor sources are based on the same Android
release.
</p>
<aside class="note"><strong>Note:</strong> Vendor modules use the current VNDK
version of the system source tree, so you must set
<code>BOARD_VNDK_VERSION</code> to <code>current</code>.
</aside>
<h3 id="set-product-extra">Setting PRODUCT_EXTRA_VNDK_VERSIONS</h3>
<p>
<code>PRODUCT_EXTRA_VNDK_VERSIONS</code> lists the extra VNDK versions to be
installed. Normally it is enough to have one VNDK snapshot for the current
vendor partition. However, in some cases you might need to include multiple
snapshots in one system image. For example, Generic System Image (GSI) has
multiple snapshots to support multiple vendor versions with one system image.
By setting <code>PRODUCT_EXTRA_VNDK_VERSIONS</code>, you can install the VNDK
snapshot modules in addition to the VNDK version in
<code>BOARD_VNDK_VERSION</code>.
</p>
<p>
If <code>PRODUCT_EXTRA_VNDK_VERSIONS</code> has a specific list of versions,
the build system looks for pre-built snapshots of the version list in the
<code>prebuilts/vndk</code> directory. If the build system locates all listed
snapshots, it installs those snapshot files to each
<code>out/target/product/<board>/system/lib[64]/vndk[-sp]-${VER}</code>.
Missing versions generate a build error.
</p>
<p>
The VNDK modules will not link with the vendor modules at build time but may
be used at runtime if the vendor modules in vendor partition require one of
the installed VNDK versions. <code>PRODUCT_EXTRA_VNDK_VERSIONS</code> is valid
only if <code>BOARD_VNDK_VERSION</code> is defined. For example, to install
the O MR1 VNDK snapshot to system.img:
</p>
<pre class="prettyprint">
$ m -j PRODUCT_EXTRA_VNDK_VERSIONS=27
</pre>
<h3 id="platform-vndk">PLATFORM_VNDK_VERSION</h3>
<p>
<code>PLATFORM_VNDK_VERSION</code> defines the VNDK version for current VNDK
modules in the system source. The value is set automatically:
</p>
<ul>
<li>Prior to release, the <code>PLATFORM_VNDK_VERSION</code> is set as
<code>PLATFORM_VERSION_CODENAME</code>.</li>
<li>At release, <code>PLATFORM_SDK_VERSION</code> is copied to
<code>PLATFORM_VNDK_VERSION</code>.</li>
</ul>
<p>
After the Android version is released, the current VNDK libraries are
installed to <code>/system/lib[64]/vndk-$SDK_VER</code> and
<code>/system/lib[64]/vndk-sp-$SDK_VER</code>, where <code>$SDK_VER</code> is
the version stored in <code>PLATFORM_VNDK_VERSION</code>.
</p>
<h3 id="namespace-config">Namespace configuration</h3>
<p>
The vendor modules search the required shared libraries using the namespace
configuration in <code>/etc/ld.config.${VER}.txt</code> (where
<code>${VER}</code> is obtained from the <code>ro.vndk.version</code>
property). The namespace configuration has a versioned VNDK directory that
uses the following syntax:
</p>
<ul>
<li><code>/system/${LIB}/vndk-%VNDK_VER%</code></li>
<li><code>/system/${LIB}/vndk-sp-%VNDK_VER%</code></li>
</ul>
<p>
<code>%VNDK_VER%</code> is replaced with <code>PLATFORM_VNDK_VERSION</code>
at build time, enabling a system image to provide multiple snapshots for each
VNDK version.
</p>
<p>
When <code>BOARD_VNDK_VERSION</code> is set to <code>current</code>, the
<code>PLATFORM_VNDK_VERSION</code> is stored in <code>ro.vndk.version</code>,
otherwise <code>BOARD_VNDK_VERSION </code>is stored in
<code>ro.vndk.version</code>. <code>PLATFORM_VNDK_VERSION</code> is set to the
SDK version when Android releases; prior to release, the alphanumeric Android
code name is used for <code>PLATFORM_VNDK_VERSION</code>.
</p>
<h3 id="summary-vndk-version-settings">Summary of VNDK version settings</h3>
<p>
The table below summarizes the VNDK version settings.
</p>
<table>
<thead>
<tr>
<th width="15%">Vendor<br>Build</th>
<th>Board<br>Version</th>
<th>SDK<br>Release</th>
<th>Platform<br>Version</th>
<th>Version<br>Property</th>
<th>Install Directory</th>
</tr>
</thead>
<tbody>
<tr>
<td rowspan=2>Current VNDK modules</td>
<td rowspan=2><code>current</code></td>
<td>Before</td>
<td><CODE_NAME></td>
<td><CODE_NAME></td>
<td>/system/lib[64]/vndk[-sp]-<CODE_NAME></td>
</tr>
<tr>
<td>After</td>
<td><SDK_ver></td>
<td><SDK_ver></td>
<td>/system/lib[64]/vndk[-sp]-<SDK_ver></td>
</tr>
<tr>
<td>Prebuilt snapshot modules</td>
<td><VNDK_ver><br>for snapshot</td>
<td>Before or After</td>
<td><CODE_NAME><br>or <SDK_ver></td>
<td><VNDK_ver></td>
<td>/system/lib[64]/vndk[-sp]-<VNDK_ver></td>
</tr>
</tbody>
</table>
<ul>
<li><strong>Board Version</strong> (<code>BOARD_VNDK_VERSION</code>). VNDK
version that vendor modules require to build. Set to <code>current</code> if
vendor modules can link with current system modules.</li>
<li><strong>Platform Version</strong> (<code>PLATFORM_VNDK_VERSION</code>).
VNDK version that current system modules are building. Built only when
<code>BOARD_VNDK_VERSION</code> equals current.</li>
<li><strong>Version Property</strong> (<code>ro.vndk.version</code>). Property
that specifies the VNDK version the binaries and libs in vendor.img require to
run. Stored in the vendor.img at<code> /vendor/default.prop</code>.</li>
</ul>
</body>
</html>
|
