summaryrefslogtreecommitdiffstats
path: root/documentation/ref-manual/ref-structure.xml
blob: 13803f5a411c853352629ddf46ee30c0bd3ab156 (plain)
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
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
<!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='ref-structure'>

<title>Source Directory Structure</title>

<para>
    The <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink> consists of several components.
    Understanding them and knowing where they are located is key to using the Yocto Project well.
    This chapter describes the Source Directory and gives information about the various
    files and directories.
</para>

<para>
    For information on how to establish a local Source Directory on your development system, see the
    "<ulink url='&YOCTO_DOCS_DEV_URL;#getting-setup'>Getting Set Up</ulink>"
    section in the Yocto Project Development Manual.
</para>

<note>
    The OpenEmbedded build system does not support file or directory names that
    contain spaces.
    Be sure that the Source Directory you use does not contain these types
    of names.
</note>

<section id='structure-core'>
    <title>Top-Level Core Components</title>

    <para>
        This section describes the top-level components of the
        <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
    </para>

    <section id='structure-core-bitbake'>
        <title><filename>bitbake/</filename></title>

        <para>
            This directory includes a copy of BitBake for ease of use.
            The copy usually matches the current stable BitBake release from the BitBake project.
            BitBake, a
            <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink>
            interpreter, reads the Yocto Project metadata and runs the tasks
            defined by that data.
            Failures are usually from the metadata and not from BitBake itself.
            Consequently, most users do not need to worry about BitBake.
        </para>

        <para>
            When you run the <filename>bitbake</filename> command, the wrapper script in
            <filename>scripts/</filename> is executed to run the main BitBake executable,
            which resides in the <filename>bitbake/bin/</filename> directory.
            Sourcing the <link linkend="structure-core-script"><filename>&OE_INIT_FILE;</filename></link>
            script places the <filename>scripts</filename> and <filename>bitbake/bin</filename>
            directories (in that order) into the shell's <filename>PATH</filename> environment
            variable.
        </para>

        <para>
            For more information on BitBake, see the BitBake documentation
            included in the <filename>bitbake/doc/manual</filename> directory of the
            <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
        </para>
    </section>

    <section id='structure-core-build'>
        <title><filename>build/</filename></title>

        <para>
            This directory contains user configuration files and the output
            generated by the OpenEmbedded build system in its standard configuration where
            the source tree is combined with the output.
            The <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
            is created initially when you <filename>source</filename>
            the OpenEmbedded 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>).
        </para>

        <para>
            It is also possible to place output and configuration
            files in a directory separate from the
            <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>
            by providing a directory name when you <filename>source</filename>
            the setup script.
            For information on separating output from your local
            Source Directory files, see the
            "<link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>
            and
            "<link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>"
            sections.
        </para>
    </section>

    <section id='handbook'>
        <title><filename>documentation</filename></title>

        <para>
            This directory holds the source for the Yocto Project documentation
            as well as templates and tools that allow you to generate PDF and HTML
            versions of the manuals.
            Each manual is contained in a sub-folder.
            For example, the files for this manual reside in
            <filename>ref-manual</filename>.
        </para>
    </section>

    <section id='structure-core-meta'>
        <title><filename>meta/</filename></title>

        <para>
            This directory contains the OpenEmbedded Core metadata.
            The directory holds recipes, common classes, and machine
            configuration for emulated targets (<filename>qemux86</filename>,
            <filename>qemuarm</filename>, and so forth.)
        </para>
    </section>

    <section id='structure-core-meta-yocto'>
        <title><filename>meta-yocto/</filename></title>

        <para>
            This directory contains the configuration for the Poky
            reference distribution.
        </para>
    </section>

    <section id='structure-core-meta-yocto-bsp'>
        <title><filename>meta-yocto-bsp/</filename></title>

        <para>
            This directory contains the Yocto Project reference
            hardware Board Support Packages (BSPs).
            For more information on BSPs, see the
            <ulink url='&YOCTO_DOCS_BSP_URL;'>Yocto Project Board Support
            Package (BSP) Developer's Guide</ulink>.
        </para>
    </section>

    <section id='structure-meta-hob'>
        <title><filename>meta-hob/</filename></title>

        <para>
            This directory contains template recipes used by Hob,
            which is a Yocto Project build user interface.
            For more information on the Hob, see the
            <ulink url='&YOCTO_HOME_URL;/tools-resources/projects/hob'>Hob Project</ulink>
            web page.
        </para>
    </section>

    <section id='structure-meta-skeleton'>
        <title><filename>meta-skeleton/</filename></title>

        <para>
            This directory contains template recipes for BSP and kernel development.
        </para>
    </section>

    <section id='structure-core-scripts'>
        <title><filename>scripts/</filename></title>

        <para>
            This directory contains various integration scripts that implement
            extra functionality in the Yocto Project environment (e.g. QEMU scripts).
            The <link linkend="structure-core-script"><filename>&OE_INIT_FILE;</filename></link>
            and
            <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>
            scripts append this directory to the shell's
            <filename>PATH</filename> environment variable.
        </para>

        <para>
            The <filename>scripts</filename> directory has useful scripts that assist contributing
            back to the Yocto Project, such as <filename>create_pull_request</filename> and
            <filename>send_pull_request</filename>.
        </para>
    </section>

    <section id='structure-core-script'>
        <title><filename>&OE_INIT_FILE;</filename></title>

        <para>
            This script is one of two scripts that set up the OpenEmbedded build 
            environment.
            For information on the other script, see the 
            "<link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>"
            section.
        </para>

        <para>
            Running this script with the <filename>source</filename> command in
            a shell makes changes to <filename>PATH</filename> and sets other
            core BitBake variables based on the current working directory.
            You need to run an environment setup script before running BitBake 
            commands.
            The script uses other scripts within the
            <filename>scripts</filename> directory to do the bulk of the work.
        </para>

        <para>
            By default, running this script without a
            <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
            argument creates the <filename>build</filename> directory.
            If you provide a Build Directory argument when you
            <filename>source</filename> the script, you direct the OpenEmbedded
            build system to create a Build Directory of your choice.
            For example, the following command creates a Build Directory named
            <filename>mybuilds</filename> that is outside of the
            <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>:
            <literallayout class='monospaced'>
     $ source &OE_INIT_FILE; ~/mybuilds
            </literallayout>
            <note>
                The OpenEmbedded build system does not support file or directory names that
                contain spaces.
                If you attempt to run the <filename>&OE_INIT_FILE;</filename> script
                from a Source Directory that contains spaces in either the filenames
                or directory names, the script returns an error indicating no such
                file or directory.
                Be sure to use a Source Directory free of names containing spaces.
            </note>
        </para>
    </section>

    <section id='structure-memres-core-script'>
        <title><filename>oe-init-build-env-memres</filename></title>

        <para>
            This script is one of two scripts that set up the OpenEmbedded build 
            environment.
            Setting up the environment with this script uses a 
            memory-resident BitBake.
            For information on the other setup script, see the 
            "<link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link>"
            section.
        </para>

        <para>
            Memory-resident BitBake resides in memory until you specifically
            remove it using the following BitBake command:
            <literallayout class='monospaced'>
     $ bitbake -m
            </literallayout>
        </para>

        <para>
            Running this script with the <filename>source</filename> command in
            a shell makes changes to <filename>PATH</filename> and sets other
            core BitBake variables based on the current working directory.
            One of these variables is the 
            <link linkend='var-BBSERVER'><filename>BBSERVER</filename></link>
            variable, which allows the OpenEmbedded build system to locate 
            the server that is running BitBake.
        </para>

        <para>
            You need to run an environment setup script before running BitBake 
            commands.
            Following is the script syntax:
            <literallayout class='monospaced'>
     $ source oe-init-build-env-memres &lt;port_number&gt; &lt;build_dir&gt;
            </literallayout>
            The script uses other scripts within the
            <filename>scripts</filename> directory to do the bulk of the work.
        </para>

        <para>
            If you do not provide a port number with the script, the default
            port "12345" is used.
        </para>

        <para>
            By default, running this script without a
            <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
            argument creates the <filename>build</filename> directory.
            If you provide a Build Directory argument when you
            <filename>source</filename> the script, you direct the OpenEmbedded
            build system to create a Build Directory of your choice.
            For example, the following command uses the default port number
            "12345" and creates a Build Directory named
            <filename>mybuilds</filename> that is outside of the
            <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>:
            <literallayout class='monospaced'>
     $ source oe-init-build-env-memres ~/mybuilds
            </literallayout>
            <note>
                The OpenEmbedded build system does not support file or 
                directory names that contain spaces.
                If you attempt to run the 
                <filename>oe-init-build-env-memres</filename> script
                from a Source Directory that contains spaces in either the 
                filenames or directory names, the script returns an error 
                indicating no such file or directory.
                Be sure to use a Source Directory free of names containing 
                spaces.
            </note>
        </para>
    </section>

    <section id='structure-basic-top-level'>
        <title><filename>LICENSE, README, and README.hardware</filename></title>

        <para>
            These files are standard top-level files.
        </para>
    </section>
</section>

<section id='structure-build'>
    <title>The Build Directory - <filename>build/</filename></title>

    <para>
        The OpenEmbedded build system creates the
        <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink>
        during the build.
        By default, this directory is named <filename>build</filename>.
    </para>

    <section id='structure-build-pseudodone'>
        <title><filename>build/pseudodone</filename></title>

        <para>
            This tag file indicates that the initial pseudo binary was created.
            The file is built the first time BitBake is invoked.
        </para>
    </section>

    <section id='structure-build-conf-local.conf'>
        <title><filename>build/conf/local.conf</filename></title>

        <para>
            This configuration file contains all the local user configurations 
            for your build environment.
            The <filename>local.conf</filename> file contains documentation on 
            the various configuration options.
            Any variable set here overrides any variable set elsewhere within 
            the environment unless that variable is hard-coded within a file 
            (e.g. by using '=' instead of '?=').
            Some variables are hard-coded for various reasons but these 
            variables are relatively rare.
        </para>

        <para>
            Edit this file to set the 
            <filename><link linkend='var-MACHINE'>MACHINE</link></filename>
            for which you want to build, which package types you wish to use
            (<link linkend='var-PACKAGE_CLASSES'><filename>PACKAGE_CLASSES</filename></link>),
            the location from which you want to downloaded files
            (<filename><link linkend='var-DL_DIR'>DL_DIR</link></filename>),
            and how you want your host machine to use resources
            (<link linkend='var-BB_NUMBER_THREADS'><filename>BB_NUMBER_THREADS</filename></link> 
            and
            <link linkend='var-PARALLEL_MAKE'><filename>PARALLEL_MAKE</filename></link>).
        </para>

        <para>
            If <filename>local.conf</filename> is not present when you 
            start the build, the OpenEmbedded build system creates it from 
            <filename>local.conf.sample</filename> when
            you <filename>source</filename> the top-level 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>).
        </para>

        <para>
            The source <filename>local.conf.sample</filename> file used 
            depends on the <filename>$TEMPLATECONF</filename> script variable,
            which defaults to <filename>/meta-yocto/conf</filename>
            when you are building from the Yocto Project development 
            environment and defaults to <filename>/meta/conf</filename> when 
            you are building from the OpenEmbedded Core environment.
            Because the script variable points to the source of the 
            <filename>local.conf.sample</filename> file, this implies that 
            you can configure your build environment from any layer by setting     
            the variable in the top-level build environment setup script as 
            follows:
            <literallayout class='monospaced'>
     TEMPLATECONF=&lt;your_layer&gt;/conf
            </literallayout>
            Once the build process gets the sample file, it uses 
            <filename>sed</filename> to substitute final 
            <filename>${</filename><link linkend='var-OEROOT'><filename>OEROOT</filename></link><filename>}</filename> 
            values for all <filename>##OEROOT##</filename> values.
            <note>
                You can see how the <filename>TEMPLATECONF</filename> variable
                is used by looking at the       
                <filename>/scripts/oe-setup-builddir</filename> script in the 
                <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
                You can find the Yocto Project version of the 
                <filename>local.conf.sample</filename> file in the 
                <filename>/meta-yocto/conf</filename> directory.                
            </note>
        </para>
    </section>

    <section id='structure-build-conf-bblayers.conf'>
        <title><filename>build/conf/bblayers.conf</filename></title>

        <para>
            This configuration file defines
            <ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>layers</ulink>,
            which are directory trees, traversed (or walked) by BitBake.
            The <filename>bblayers.conf</filename> file uses the
            <link linkend='var-BBLAYERS'><filename>BBLAYERS</filename></link> 
            variable to list the layers BitBake tries to find, and uses the
            <link linkend='var-BBLAYERS_NON_REMOVABLE'><filename>BBLAYERS_NON_REMOVABLE</filename></link>
            variable to list layers that must not be removed.
        </para>

        <para>
            If <filename>bblayers.conf</filename> is not present when you 
            start the build, the OpenEmbedded build system creates it from 
            <filename>bblayers.conf.sample</filename> when
            you <filename>source</filename> the top-level 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>).
        </para>

        <para>
            The source <filename>bblayers.conf.sample</filename> file used 
            depends on the <filename>$TEMPLATECONF</filename> script variable,
            which defaults to <filename>/meta-yocto/conf</filename>
            when you are building from the Yocto Project development 
            environment and defaults to <filename>/meta/conf</filename> when 
            you are building from the OpenEmbedded Core environment.
            Because the script variable points to the source of the 
            <filename>bblayers.conf.sample</filename> file, this implies that 
            you can base your build from any layer by setting the variable in
            the top-level build environment setup script as follows:
            <literallayout class='monospaced'>
     TEMPLATECONF=&lt;your_layer&gt;/conf
            </literallayout>
            Once the build process gets the sample file, it uses 
            <filename>sed</filename> to substitute final 
            <filename>${</filename><link linkend='var-OEROOT'><filename>OEROOT</filename></link><filename>}</filename> 
            values for all <filename>##OEROOT##</filename> values.
            <note>
                You can see how the <filename>TEMPLATECONF</filename> variable
                <filename>/scripts/oe-setup-builddir</filename> script in the 
                <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
                You can find the Yocto Project version of the 
                <filename>bblayers.conf.sample</filename> file in the 
                <filename>/meta-yocto/conf</filename> directory.                
            </note>
        </para>
    </section>

    <section id='structure-build-conf-sanity_info'>
        <title><filename>build/conf/sanity_info</filename></title>

        <para>
            This file indicates the state of the sanity checks and is created
            during the build.
        </para>
    </section>

    <section id='structure-build-downloads'>
        <title><filename>build/downloads/</filename></title>

        <para>
            This directory contains downloaded upstream source tarballs.
            You can reuse the directory for multiple builds or move
            the directory to another location.
            You can control the location of this directory through the
            <filename><link linkend='var-DL_DIR'>DL_DIR</link></filename> variable.
        </para>
    </section>

    <section id='structure-build-sstate-cache'>
        <title><filename>build/sstate-cache/</filename></title>

        <para>
            This directory contains the shared state cache.
            You can reuse the directory for multiple builds or move
            the directory to another location.
            You can control the location of this directory through the
            <filename><link linkend='var-SSTATE_DIR'>SSTATE_DIR</link></filename> variable.
        </para>
    </section>

    <section id='structure-build-tmp'>
        <title><filename>build/tmp/</filename></title>

        <para>
            This directory receives all the OpenEmbedded build system's output.
            BitBake creates this directory if it does not exist.
            As a last resort, to clean up a build and start it from scratch (other than the downloads),
            you can remove everything in the <filename>tmp</filename> directory or get rid of the
            directory completely.
            If you do, you should also completely remove the
            <filename>build/sstate-cache</filename> directory.
        </para>
    </section>

    <section id='structure-build-tmp-buildstats'>
        <title><filename>build/tmp/buildstats/</filename></title>

        <para>
            This directory stores the build statistics.
        </para>
    </section>

    <section id='structure-build-tmp-cache'>
        <title><filename>build/tmp/cache/</filename></title>

        <para>
            When BitBake parses the metadata, it creates a cache file of the result that can
            be used when subsequently running commands.
            BitBake stores these results here on a per-machine basis.
        </para>
    </section>

    <section id='structure-build-tmp-deploy'>
        <title><filename>build/tmp/deploy/</filename></title>

        <para>
            This directory contains any "end result" output from the
            OpenEmbedded build process.
            The <link linkend='var-DEPLOY_DIR'><filename>DEPLOY_DIR</filename></link>
            variable points to this directory.
            For more detail on the contents of the <filename>deploy</filename>
            directory, see the
            "<link linkend='images-dev-environment'>Images</link>" and
            "<link linkend='sdk-dev-environment'>Application Development SDK</link>"
            sections.
        </para>
    </section>

    <section id='structure-build-tmp-deploy-deb'>
        <title><filename>build/tmp/deploy/deb/</filename></title>

        <para>
            This directory receives any <filename>.deb</filename> packages produced by
            the build process.
            The packages are sorted into feeds for different architecture types.
        </para>
    </section>

    <section id='structure-build-tmp-deploy-rpm'>
        <title><filename>build/tmp/deploy/rpm/</filename></title>

        <para>
            This directory receives any <filename>.rpm</filename> packages produced by
            the build process.
            The packages are sorted into feeds for different architecture types.
        </para>
    </section>

    <section id='structure-build-tmp-deploy-licenses'>
        <title><filename>build/tmp/deploy/licenses/</filename></title>

        <para>
            This directory receives package licensing information.
            For example, the directory contains sub-directories for <filename>bash</filename>,
            <filename>busybox</filename>, and <filename>eglibc</filename> (among others) that in turn
            contain appropriate <filename>COPYING</filename> license files with other licensing information.
            For information on licensing, see the
            "<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>"
            section.
        </para>
    </section>

    <section id='structure-build-tmp-deploy-images'>
        <title><filename>build/tmp/deploy/images/</filename></title>

        <para>
            This directory receives complete filesystem images.
            If you want to flash the resulting image from a build onto a device, look here for the image.
        </para>

        <para>
            Be careful when deleting files in this directory.
            You can safely delete old images from this directory (e.g.
            <filename>core-image-*</filename>, <filename>hob-image-*</filename>,
            etc.).
            However, the kernel (<filename>*zImage*</filename>, <filename>*uImage*</filename>, etc.),
            bootloader and other supplementary files might be deployed here prior to building an
            image.
            Because these files are not directly produced from the image, if you
            delete them they will not be automatically re-created when you build the image again.
        </para>

        <para>
            If you do accidentally delete files here, you will need to force them to be
            re-created.
            In order to do that, you will need to know the target that produced them.
            For example, these commands rebuild and re-create the kernel files:
            <literallayout class='monospaced'>
     $ bitbake -c clean virtual/kernel
     $ bitbake virtual/kernel
            </literallayout>
        </para>
    </section>

    <section id='structure-build-tmp-deploy-ipk'>
        <title><filename>build/tmp/deploy/ipk/</filename></title>

        <para>
            This directory receives <filename>.ipk</filename> packages produced by
            the build process.</para>
    </section>

    <section id='structure-build-tmp-sysroots'>
        <title><filename>build/tmp/sysroots/</filename></title>

        <para>
            This directory contains shared header files and libraries as well as other shared
            data.
            Packages that need to share output with other packages do so within this directory.
            The directory is subdivided by architecture so multiple builds can run within
            the one Build Directory.
        </para>
    </section>

    <section id='structure-build-tmp-stamps'>
        <title><filename>build/tmp/stamps/</filename></title>

        <para>
            This directory holds information that BitBake uses for accounting purposes
            to track what tasks have run and when they have run.
            The directory is sub-divided by architecture, package name, and
            version.
            Following is an example:
            <literallayout class='monospaced'>
     stamps/all-poky-linux/distcc-config/1.0-r0.do_build-2fdd....2do
            </literallayout>
            Although the files in the directory are empty of data,
            BitBake uses the filenames and timestamps for tracking purposes.
        </para>
    </section>

    <section id='structure-build-tmp-log'>
        <title><filename>build/tmp/log/</filename></title>

        <para>
            This directory contains general logs that are not otherwise placed using the
            package's <filename><link linkend='var-WORKDIR'>WORKDIR</link></filename>.
            Examples of logs are the output from the <filename>check_pkg</filename> or
            <filename>distro_check</filename> tasks.
            Running a build does not necessarily mean this directory is created.
        </para>
    </section>

    <section id='structure-build-tmp-pkgdata'>
        <title><filename>build/tmp/pkgdata/</filename></title>

        <para>
            This directory contains intermediate packaging data that is used later in the packaging process.
            For more information, see the "<link linkend='ref-classes-package'>Packaging - package*.bbclass</link>" section.
        </para>
    </section>

    <section id='structure-build-tmp-work'>
        <title><filename>build/tmp/work/</filename></title>

        <para>
            This directory contains architecture-specific work sub-directories
            for packages built by BitBake.
            All tasks execute from the appropriate work directory.
            For example, the source for a particular package is unpacked,
            patched, configured and compiled all within its own work directory.
            Within the work directory, organization is based on the package group
            and version for which the source is being compiled
            as defined by the
            <link linkend='var-WORKDIR'><filename>WORKDIR</filename></link>.
        </para>

        <para>
            It is worth considering the structure of a typical work directory.
            As an example, consider <filename>linux-yocto-kernel-3.0</filename>
            on the machine <filename>qemux86</filename>
            built within the Yocto Project.
            For this package, a work directory of
            <filename>tmp/work/qemux86-poky-linux/linux-yocto/3.0+git1+&lt;.....&gt;</filename>,
            referred to as the
            <filename><link linkend='var-WORKDIR'>WORKDIR</link></filename>, is created.
            Within this directory, the source is unpacked to
            <filename>linux-qemux86-standard-build</filename> and then patched by Quilt.
            (See the
            "<ulink url='&YOCTO_DOCS_DEV_URL;#using-a-quilt-workflow'>Using a Quilt Flow</ulink>"
            section in the Yocto Project Development Manual for more information.)
            Within the <filename>linux-qemux86-standard-build</filename> directory,
            standard Quilt directories <filename>linux-3.0/patches</filename>
            and <filename>linux-3.0/.pc</filename> are created,
            and standard Quilt commands can be used.
        </para>

        <para>
            There are other directories generated within <filename>WORKDIR</filename>.
            The most important directory is <filename>WORKDIR/temp/</filename>,
            which has log files for each task (<filename>log.do_*.pid</filename>)
            and contains the scripts BitBake runs for each task
            (<filename>run.do_*.pid</filename>).
            The <filename>WORKDIR/image/</filename> directory is where "make
            install" places its output that is then split into sub-packages
            within <filename>WORKDIR/packages-split/</filename>.
        </para>
    </section>
</section>

<section id='structure-meta'>
    <title>The Metadata - <filename>meta/</filename></title>

    <para>
        As mentioned previously,
        <ulink url='&YOCTO_DOCS_DEV_URL;#metadata'>Metadata</ulink> is the core
        of the Yocto Project.
        Metadata has several important subdivisions:
    </para>

    <section id='structure-meta-classes'>
        <title><filename>meta/classes/</filename></title>

        <para>
            This directory contains the <filename>*.bbclass</filename> files.
            Class files are used to abstract common code so it can be reused by multiple
            packages.
            Every package inherits the <filename>base.bbclass</filename> file.
            Examples of other important classes are <filename>autotools.bbclass</filename>, which
            in theory allows any Autotool-enabled package to work with the Yocto Project with minimal effort.
            Another example is <filename>kernel.bbclass</filename> that contains common code and functions
            for working with the Linux kernel.
            Functions like image generation or packaging also have their specific class files
            such as <filename>image.bbclass</filename>, <filename>rootfs_*.bbclass</filename> and
            <filename>package*.bbclass</filename>.
        </para>

        <para>
            For reference information on classes, see the
            "<link linkend='ref-classes'>Classes</link>" chapter.
        </para>
    </section>

    <section id='structure-meta-conf'>
        <title><filename>meta/conf/</filename></title>

        <para>
            This directory contains the core set of configuration files that start from
            <filename>bitbake.conf</filename> and from which all other configuration
            files are included.
            See the include statements at the end of the
            <filename>bitbake.conf</filename> file and you will note that even
            <filename>local.conf</filename> is loaded from there.
            While <filename>bitbake.conf</filename> sets up the defaults, you can often override
            these by using the (<filename>local.conf</filename>) file, machine file or
            the distribution configuration file.
        </para>
    </section>

    <section id='structure-meta-conf-machine'>
        <title><filename>meta/conf/machine/</filename></title>

        <para>
            This directory contains all the machine configuration files.
            If you set <filename>MACHINE = "qemux86"</filename>,
            the OpenEmbedded build system looks for a <filename>qemux86.conf</filename> file in this
            directory.
            The <filename>include</filename> directory contains various data common to multiple machines.
            If you want to add support for a new machine to the Yocto Project, look in this directory.
        </para>
    </section>

    <section id='structure-meta-conf-distro'>
        <title><filename>meta/conf/distro/</filename></title>

        <para>
            The contents of this directory controls any distribution-specific
            configurations.
            For the Yocto Project, the <filename>defaultsetup.conf</filename> is the main file here.
            This directory includes the versions and the
            <filename>SRCDATE</filename> definitions for applications that are configured here.
            An example of an alternative configuration might be <filename>poky-bleeding.conf</filename>.
            Although this file mainly inherits its configuration from Poky.
        </para>
    </section>

    <section id='structure-meta-files'>
        <title><filename>meta/files/</filename></title>

        <para>
            This directory contains common license files and several text files
            used by the build system.
            The text files contain minimal device information and
            lists of files and directories with knows permissions.
        </para>
    </section>

    <section id='structure-meta-lib'>
        <title><filename>meta/lib/</filename></title>

        <para>
            This directory contains OpenEmbedded Python library code
            used during the build process.
        </para>
    </section>

    <section id='structure-meta-recipes-bsp'>
        <title><filename>meta/recipes-bsp/</filename></title>

        <para>
            This directory contains anything linking to specific hardware or hardware
            configuration information such as "u-boot" and "grub".
        </para>
    </section>

    <section id='structure-meta-recipes-connectivity'>
        <title><filename>meta/recipes-connectivity/</filename></title>

        <para>
            This directory contains libraries and applications related to communication with other devices.
        </para>
    </section>

    <section id='structure-meta-recipes-core'>
        <title><filename>meta/recipes-core/</filename></title>

        <para>
            This directory contains what is needed to build a basic working Linux image
            including commonly used dependencies.
        </para>
    </section>

    <section id='structure-meta-recipes-devtools'>
        <title><filename>meta/recipes-devtools/</filename></title>

        <para>
            This directory contains tools that are primarily used by the build system.
            The tools, however, can also be used on targets.
        </para>
    </section>

    <section id='structure-meta-recipes-extended'>
        <title><filename>meta/recipes-extended/</filename></title>

        <para>
            This directory contains non-essential applications that add features compared to the
            alternatives in core.
            You might need this directory for full tool functionality or for Linux Standard Base (LSB)
            compliance.
        </para>
    </section>

    <section id='structure-meta-recipes-gnome'>
        <title><filename>meta/recipes-gnome/</filename></title>

        <para>
            This directory contains all things related to the GTK+ application framework.
        </para>
    </section>

    <section id='structure-meta-recipes-graphics'>
        <title><filename>meta/recipes-graphics/</filename></title>

        <para>
            This directory contains X and other graphically related system libraries
        </para>
    </section>

    <section id='structure-meta-recipes-kernel'>
        <title><filename>meta/recipes-kernel/</filename></title>

        <para>
            This directory contains the kernel and generic applications and libraries that
            have strong kernel dependencies.
        </para>
    </section>

    <section id='structure-meta-recipes-lsb4'>
        <title><filename>meta/recipes-lsb4/</filename></title>

        <para>
            This directory contains recipes specifically added to support
            the Linux Standard Base (LSB) version 4.x.
        </para>
    </section>

    <section id='structure-meta-recipes-multimedia'>
        <title><filename>meta/recipes-multimedia/</filename></title>

        <para>
            This directory contains codecs and support utilities for audio, images and video.
        </para>
    </section>

    <section id='structure-meta-recipes-qt'>
        <title><filename>meta/recipes-qt/</filename></title>

        <para>
            This directory contains all things related to the Qt application framework.
        </para>
    </section>

    <section id='structure-meta-recipes-rt'>
        <title><filename>meta/recipes-rt/</filename></title>

        <para>
            This directory contains package and image recipes for using and testing
            the <filename>PREEMPT_RT</filename> kernel.
        </para>
    </section>

    <section id='structure-meta-recipes-sato'>
        <title><filename>meta/recipes-sato/</filename></title>

        <para>
            This directory contains the Sato demo/reference UI/UX and its associated applications
            and configuration data.
        </para>
    </section>

    <section id='structure-meta-recipes-support'>
        <title><filename>meta/recipes-support/</filename></title>

        <para>
            This directory contains recipes used by other recipes, but that are
            not directly included in images (i.e. dependencies of other
            recipes).
        </para>
    </section>

    <section id='structure-meta-site'>
        <title><filename>meta/site/</filename></title>

        <para>
            This directory contains a list of cached results for various architectures.
            Because certain "autoconf" test results cannot be determined when cross-compiling due to
            the tests not able to run on a live system, the information in this directory is
            passed to "autoconf" for the various architectures.
        </para>
    </section>

    <section id='structure-meta-recipes-txt'>
        <title><filename>meta/recipes.txt</filename></title>

        <para>
            This file is a description of the contents of <filename>recipes-*</filename>.
        </para>
    </section>
</section>

</chapter>
<!--
vim: expandtab tw=80 ts=4
-->