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1 | <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | ||
2 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" | ||
3 | [<!ENTITY % poky SYSTEM "../poky.ent"> %poky; ] > | ||
4 | |||
5 | <chapter id='faq'> | ||
6 | <title>FAQ</title> | ||
7 | <qandaset> | ||
8 | <qandaentry> | ||
9 | <question> | ||
10 | <para> | ||
11 | How does Poky differ from <ulink url='&OE_HOME_URL;'>OpenEmbedded</ulink>? | ||
12 | </para> | ||
13 | </question> | ||
14 | <answer> | ||
15 | <para> | ||
16 | The term "<ulink url='&YOCTO_DOCS_DEV_URL;#poky'>Poky</ulink>" | ||
17 | refers to the specific reference build system that | ||
18 | the Yocto Project provides. | ||
19 | Poky is based on <ulink url='&YOCTO_DOCS_DEV_URL;#oe-core'>OE-Core</ulink> | ||
20 | and <ulink url='&YOCTO_DOCS_DEV_URL;#bitbake-term'>BitBake</ulink>. | ||
21 | Thus, the generic term used here for the build system is | ||
22 | the "OpenEmbedded build system." | ||
23 | Development in the Yocto Project using Poky is closely tied to OpenEmbedded, with | ||
24 | changes always being merged to OE-Core or BitBake first before being pulled back | ||
25 | into Poky. | ||
26 | This practice benefits both projects immediately. | ||
27 | </para> | ||
28 | </answer> | ||
29 | </qandaentry> | ||
30 | |||
31 | <qandaentry> | ||
32 | <question> | ||
33 | <para id='faq-not-meeting-requirements'> | ||
34 | My development system does not meet the | ||
35 | required Git, tar, and Python versions. | ||
36 | In particular, I do not have Python 2.7.3 or greater, or | ||
37 | I do have Python 3.x, which is specifically not supported by | ||
38 | the Yocto Project. | ||
39 | Can I still use the Yocto Project? | ||
40 | </para> | ||
41 | </question> | ||
42 | <answer> | ||
43 | <para> | ||
44 | You can get the required tools on your host development | ||
45 | system a couple different ways (i.e. building a tarball or | ||
46 | downloading a tarball). | ||
47 | See the | ||
48 | "<link linkend='required-git-tar-and-python-versions'>Required Git, tar, and Python Versions</link>" | ||
49 | section for steps on how to update your build tools. | ||
50 | </para> | ||
51 | </answer> | ||
52 | </qandaentry> | ||
53 | |||
54 | <qandaentry> | ||
55 | <question> | ||
56 | <para> | ||
57 | How can you claim Poky / OpenEmbedded-Core is stable? | ||
58 | </para> | ||
59 | </question> | ||
60 | <answer> | ||
61 | <para> | ||
62 | There are three areas that help with stability; | ||
63 | <itemizedlist> | ||
64 | <listitem><para>The Yocto Project team keeps | ||
65 | <ulink url='&YOCTO_DOCS_DEV_URL;#oe-core'>OE-Core</ulink> small | ||
66 | and focused, containing around 830 recipes as opposed to the thousands | ||
67 | available in other OpenEmbedded community layers. | ||
68 | Keeping it small makes it easy to test and maintain.</para></listitem> | ||
69 | <listitem><para>The Yocto Project team runs manual and automated tests | ||
70 | using a small, fixed set of reference hardware as well as emulated | ||
71 | targets.</para></listitem> | ||
72 | <listitem><para>The Yocto Project uses an autobuilder, | ||
73 | which provides continuous build and integration tests.</para></listitem> | ||
74 | </itemizedlist> | ||
75 | </para> | ||
76 | </answer> | ||
77 | </qandaentry> | ||
78 | |||
79 | <qandaentry> | ||
80 | <question> | ||
81 | <para> | ||
82 | How do I get support for my board added to the Yocto Project? | ||
83 | </para> | ||
84 | </question> | ||
85 | <answer> | ||
86 | <para> | ||
87 | Support for an additional board is added by creating a | ||
88 | Board Support Package (BSP) layer for it. | ||
89 | For more information on how to create a BSP layer, see the | ||
90 | "<ulink url='&YOCTO_DOCS_DEV_URL;#understanding-and-creating-layers'>Understanding and Creating Layers</ulink>" | ||
91 | section in the Yocto Project Development Manual and the | ||
92 | <ulink url='&YOCTO_DOCS_BSP_URL;'>Yocto Project Board Support Package (BSP) Developer's Guide</ulink>. | ||
93 | </para> | ||
94 | <para> | ||
95 | Usually, if the board is not completely exotic, adding support in | ||
96 | the Yocto Project is fairly straightforward. | ||
97 | </para> | ||
98 | </answer> | ||
99 | </qandaentry> | ||
100 | |||
101 | <qandaentry> | ||
102 | <question> | ||
103 | <para> | ||
104 | Are there any products built using the OpenEmbedded build system? | ||
105 | </para> | ||
106 | </question> | ||
107 | <answer> | ||
108 | <para> | ||
109 | The software running on the <ulink url='http://vernier.com/labquest/'>Vernier LabQuest</ulink> | ||
110 | is built using the OpenEmbedded build system. | ||
111 | See the <ulink url='http://www.vernier.com/products/interfaces/labq/'>Vernier LabQuest</ulink> | ||
112 | website for more information. | ||
113 | There are a number of pre-production devices using the OpenEmbedded build system | ||
114 | and the Yocto Project team | ||
115 | announces them as soon as they are released. | ||
116 | </para> | ||
117 | </answer> | ||
118 | </qandaentry> | ||
119 | |||
120 | <qandaentry> | ||
121 | <question> | ||
122 | <para> | ||
123 | What does the OpenEmbedded build system produce as output? | ||
124 | </para> | ||
125 | </question> | ||
126 | <answer> | ||
127 | <para> | ||
128 | Because you can use the same set of recipes to create output of | ||
129 | various formats, the output of an OpenEmbedded build depends on | ||
130 | how you start it. | ||
131 | Usually, the output is a flashable image ready for the target | ||
132 | device. | ||
133 | </para> | ||
134 | </answer> | ||
135 | </qandaentry> | ||
136 | |||
137 | <qandaentry> | ||
138 | <question> | ||
139 | <para> | ||
140 | How do I add my package to the Yocto Project? | ||
141 | </para> | ||
142 | </question> | ||
143 | <answer> | ||
144 | <para> | ||
145 | To add a package, you need to create a BitBake recipe. | ||
146 | For information on how to create a BitBake recipe, see the | ||
147 | "<ulink url='&YOCTO_DOCS_DEV_URL;#new-recipe-writing-a-new-recipe'>Writing a New Recipe</ulink>" | ||
148 | in the Yocto Project Development Manual. | ||
149 | </para> | ||
150 | </answer> | ||
151 | </qandaentry> | ||
152 | |||
153 | <qandaentry> | ||
154 | <question> | ||
155 | <para> | ||
156 | Do I have to reflash my entire board with a new Yocto Project image when recompiling | ||
157 | a package? | ||
158 | </para> | ||
159 | </question> | ||
160 | <answer> | ||
161 | <para> | ||
162 | The OpenEmbedded build system can build packages in various | ||
163 | formats such as IPK for OPKG, Debian package | ||
164 | (<filename>.deb</filename>), or RPM. | ||
165 | You can then upgrade the packages using the package tools on | ||
166 | the device, much like on a desktop distribution such as | ||
167 | Ubuntu or Fedora. | ||
168 | However, package management on the target is entirely optional. | ||
169 | </para> | ||
170 | </answer> | ||
171 | </qandaentry> | ||
172 | |||
173 | <qandaentry> | ||
174 | <question> | ||
175 | <para> | ||
176 | What is GNOME Mobile and what is the difference between GNOME Mobile and GNOME? | ||
177 | </para> | ||
178 | </question> | ||
179 | <answer> | ||
180 | <para> | ||
181 | GNOME Mobile is a subset of the <ulink url='http://www.gnome.org'>GNOME</ulink> | ||
182 | platform targeted at mobile and embedded devices. | ||
183 | The main difference between GNOME Mobile and standard GNOME is that | ||
184 | desktop-orientated libraries have been removed, along with deprecated libraries, | ||
185 | creating a much smaller footprint. | ||
186 | </para> | ||
187 | </answer> | ||
188 | </qandaentry> | ||
189 | |||
190 | <qandaentry> | ||
191 | <question> | ||
192 | <para> | ||
193 | I see the error '<filename>chmod: XXXXX new permissions are r-xrwxrwx, not r-xr-xr-x</filename>'. | ||
194 | What is wrong? | ||
195 | </para> | ||
196 | </question> | ||
197 | <answer> | ||
198 | <para> | ||
199 | You are probably running the build on an NTFS filesystem. | ||
200 | Use <filename>ext2</filename>, <filename>ext3</filename>, or <filename>ext4</filename> instead. | ||
201 | </para> | ||
202 | </answer> | ||
203 | </qandaentry> | ||
204 | |||
205 | <!-- <qandaentry> | ||
206 | <question> | ||
207 | <para> | ||
208 | How do I make the Yocto Project work in RHEL/CentOS? | ||
209 | </para> | ||
210 | </question> | ||
211 | <answer> | ||
212 | <para> | ||
213 | To get the Yocto Project working under RHEL/CentOS 5.1 you need to first | ||
214 | install some required packages. | ||
215 | The standard CentOS packages needed are: | ||
216 | <itemizedlist> | ||
217 | <listitem><para>"Development tools" (selected during installation)</para></listitem> | ||
218 | <listitem><para><filename>texi2html</filename></para></listitem> | ||
219 | <listitem><para><filename>compat-gcc-34</filename></para></listitem> | ||
220 | </itemizedlist> | ||
221 | On top of these, you need the following external packages: | ||
222 | <itemizedlist> | ||
223 | <listitem><para><filename>python-sqlite2</filename> from | ||
224 | <ulink url='http://dag.wieers.com/rpm/packages/python-sqlite2/'>DAG repository</ulink> | ||
225 | </para></listitem> | ||
226 | <listitem><para><filename>help2man</filename> from | ||
227 | <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> | ||
228 | </itemizedlist> | ||
229 | </para> | ||
230 | |||
231 | <para> | ||
232 | Once these packages are installed, the OpenEmbedded build system will be able | ||
233 | to build standard images. | ||
234 | However, there might be a problem with the QEMU emulator segfaulting. | ||
235 | You can either disable the generation of binary locales by setting | ||
236 | <filename><link linkend='var-ENABLE_BINARY_LOCALE_GENERATION'>ENABLE_BINARY_LOCALE_GENERATION</link> | ||
237 | </filename> to "0" or by removing the <filename>linux-2.6-execshield.patch</filename> | ||
238 | from the kernel and rebuilding it since that is the patch that causes the problems with QEMU. | ||
239 | </para> | ||
240 | |||
241 | <note> | ||
242 | <para>For information on distributions that the Yocto Project | ||
243 | uses during validation, see the | ||
244 | <ulink url='&YOCTO_WIKI_URL;/wiki/Distribution_Support'>Distribution Support</ulink> | ||
245 | Wiki page.</para> | ||
246 | <para>For notes about using the Yocto Project on a RHEL 4-based | ||
247 | host, see the | ||
248 | <ulink url='&YOCTO_WIKI_URL;/wiki/BuildingOnRHEL4'>Building on RHEL4</ulink> | ||
249 | Wiki page.</para> | ||
250 | </note> | ||
251 | </answer> | ||
252 | </qandaentry> --> | ||
253 | |||
254 | <qandaentry> | ||
255 | <question> | ||
256 | <para> | ||
257 | I see lots of 404 responses for files on | ||
258 | <filename>&YOCTO_HOME_URL;/sources/*</filename>. Is something wrong? | ||
259 | </para> | ||
260 | </question> | ||
261 | <answer> | ||
262 | <para> | ||
263 | Nothing is wrong. | ||
264 | The OpenEmbedded build system checks any configured source mirrors before downloading | ||
265 | from the upstream sources. | ||
266 | The build system does this searching for both source archives and | ||
267 | pre-checked out versions of SCM-managed software. | ||
268 | These checks help in large installations because it can reduce load on the SCM servers | ||
269 | themselves. | ||
270 | The address above is one of the default mirrors configured into the | ||
271 | build system. | ||
272 | Consequently, if an upstream source disappears, the team | ||
273 | can place sources there so builds continue to work. | ||
274 | </para> | ||
275 | </answer> | ||
276 | </qandaentry> | ||
277 | |||
278 | <qandaentry> | ||
279 | <question> | ||
280 | <para> | ||
281 | I have machine-specific data in a package for one machine only but the package is | ||
282 | being marked as machine-specific in all cases, how do I prevent this? | ||
283 | </para> | ||
284 | </question> | ||
285 | <answer> | ||
286 | <para> | ||
287 | Set <filename><link linkend='var-SRC_URI_OVERRIDES_PACKAGE_ARCH'>SRC_URI_OVERRIDES_PACKAGE_ARCH</link> | ||
288 | </filename> = "0" in the <filename>.bb</filename> file but make sure the package is | ||
289 | manually marked as | ||
290 | machine-specific for the case that needs it. | ||
291 | The code that handles | ||
292 | <filename>SRC_URI_OVERRIDES_PACKAGE_ARCH</filename> is in | ||
293 | the <filename>meta/classes/base.bbclass</filename> file. | ||
294 | </para> | ||
295 | </answer> | ||
296 | </qandaentry> | ||
297 | |||
298 | <qandaentry> | ||
299 | <question> | ||
300 | <para> | ||
301 | I'm behind a firewall and need to use a proxy server. How do I do that? | ||
302 | </para> | ||
303 | </question> | ||
304 | <answer> | ||
305 | <para> | ||
306 | Most source fetching by the OpenEmbedded build system is done by <filename>wget</filename> | ||
307 | and you therefore need to specify the proxy settings in a | ||
308 | <filename>.wgetrc</filename> file in your home directory. | ||
309 | Here are some example settings: | ||
310 | <literallayout class='monospaced'> | ||
311 | http_proxy = http://proxy.yoyodyne.com:18023/ | ||
312 | ftp_proxy = http://proxy.yoyodyne.com:18023/ | ||
313 | </literallayout> | ||
314 | The Yocto Project also includes a | ||
315 | <filename>site.conf.sample</filename> file that shows how to | ||
316 | configure CVS and Git proxy servers if needed. | ||
317 | </para> | ||
318 | </answer> | ||
319 | </qandaentry> | ||
320 | |||
321 | <qandaentry> | ||
322 | <question> | ||
323 | <para> | ||
324 | What’s the difference between <filename>foo</filename> and <filename>foo-native</filename>? | ||
325 | </para> | ||
326 | </question> | ||
327 | <answer> | ||
328 | <para> | ||
329 | The <filename>*-native</filename> targets are designed to run on the system | ||
330 | being used for the build. | ||
331 | These are usually tools that are needed to assist the build in some way such as | ||
332 | <filename>quilt-native</filename>, which is used to apply patches. | ||
333 | The non-native version is the one that runs on the target device. | ||
334 | </para> | ||
335 | </answer> | ||
336 | </qandaentry> | ||
337 | |||
338 | <qandaentry> | ||
339 | <question> | ||
340 | <para> | ||
341 | I'm seeing random build failures. Help?! | ||
342 | </para> | ||
343 | </question> | ||
344 | <answer> | ||
345 | <para> | ||
346 | If the same build is failing in totally different and random | ||
347 | ways, the most likely explanation is: | ||
348 | <itemizedlist> | ||
349 | <listitem><para>The hardware you are running the build on | ||
350 | has some problem.</para></listitem> | ||
351 | <listitem><para>You are running the build under | ||
352 | virtualization, in which case the virtualization | ||
353 | probably has bugs.</para></listitem> | ||
354 | </itemizedlist> | ||
355 | The OpenEmbedded build system processes a massive amount of | ||
356 | data that causes lots of network, disk and CPU activity and | ||
357 | is sensitive to even single-bit failures in any of these areas. | ||
358 | True random failures have always been traced back to hardware | ||
359 | or virtualization issues. | ||
360 | </para> | ||
361 | </answer> | ||
362 | </qandaentry> | ||
363 | |||
364 | <qandaentry> | ||
365 | <question> | ||
366 | <para> | ||
367 | What do we need to ship for license compliance? | ||
368 | </para> | ||
369 | </question> | ||
370 | <answer> | ||
371 | <para> | ||
372 | This is a difficult question and you need to consult your lawyer | ||
373 | for the answer for your specific case. | ||
374 | It is worth bearing in mind that for GPL compliance, there needs | ||
375 | to be enough information shipped to allow someone else to | ||
376 | rebuild and produce the same end result you are shipping. | ||
377 | This means sharing the source code, any patches applied to it, | ||
378 | and also any configuration information about how that package | ||
379 | was configured and built. | ||
380 | </para> | ||
381 | |||
382 | <para> | ||
383 | You can find more information on licensing in the | ||
384 | "<ulink url='&YOCTO_DOCS_DEV_URL;#licensing'>Licensing</ulink>" | ||
385 | 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>" | ||
386 | sections, both of which are in the Yocto Project Development | ||
387 | Manual. | ||
388 | </para> | ||
389 | </answer> | ||
390 | </qandaentry> | ||
391 | |||
392 | <qandaentry> | ||
393 | <question> | ||
394 | <para> | ||
395 | How do I disable the cursor on my touchscreen device? | ||
396 | </para> | ||
397 | </question> | ||
398 | <answer> | ||
399 | <para> | ||
400 | You need to create a form factor file as described in the | ||
401 | "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout-misc-recipes'>Miscellaneous BSP-Specific Recipe Files</ulink>" | ||
402 | section in the Yocto Project Board Support Packages (BSP) | ||
403 | Developer's Guide. | ||
404 | Set the <filename>HAVE_TOUCHSCREEN</filename> variable equal to | ||
405 | one as follows: | ||
406 | <literallayout class='monospaced'> | ||
407 | HAVE_TOUCHSCREEN=1 | ||
408 | </literallayout> | ||
409 | </para> | ||
410 | </answer> | ||
411 | </qandaentry> | ||
412 | |||
413 | <qandaentry> | ||
414 | <question> | ||
415 | <para> | ||
416 | How do I make sure connected network interfaces are brought up by default? | ||
417 | </para> | ||
418 | </question> | ||
419 | <answer> | ||
420 | <para> | ||
421 | The default interfaces file provided by the netbase recipe does not | ||
422 | automatically bring up network interfaces. | ||
423 | Therefore, you will need to add a BSP-specific netbase that includes an interfaces | ||
424 | file. | ||
425 | See the "<ulink url='&YOCTO_DOCS_BSP_URL;#bsp-filelayout-misc-recipes'>Miscellaneous BSP-Specific Recipe Files</ulink>" | ||
426 | section in the Yocto Project Board Support Packages (BSP) | ||
427 | Developer's Guide for information on creating these types of | ||
428 | miscellaneous recipe files. | ||
429 | </para> | ||
430 | <para> | ||
431 | For example, add the following files to your layer: | ||
432 | <literallayout class='monospaced'> | ||
433 | meta-MACHINE/recipes-bsp/netbase/netbase/MACHINE/interfaces | ||
434 | meta-MACHINE/recipes-bsp/netbase/netbase_5.0.bbappend | ||
435 | </literallayout> | ||
436 | </para> | ||
437 | </answer> | ||
438 | </qandaentry> | ||
439 | |||
440 | <qandaentry> | ||
441 | <question> | ||
442 | <para> | ||
443 | How do I create images with more free space? | ||
444 | </para> | ||
445 | </question> | ||
446 | <answer> | ||
447 | <para> | ||
448 | By default, the OpenEmbedded build system creates images | ||
449 | that are 1.3 times the size of the populated root filesystem. | ||
450 | To affect the image size, you need to set various | ||
451 | configurations: | ||
452 | <itemizedlist> | ||
453 | <listitem><para><emphasis>Image Size:</emphasis> | ||
454 | The OpenEmbedded build system uses the | ||
455 | <link linkend='var-IMAGE_ROOTFS_SIZE'><filename>IMAGE_ROOTFS_SIZE</filename></link> | ||
456 | variable to define the size of the image in Kbytes. | ||
457 | The build system determines the size by taking into | ||
458 | account the initial root filesystem size before any | ||
459 | modifications such as requested size for the image and | ||
460 | any requested additional free disk space to be | ||
461 | added to the image.</para></listitem> | ||
462 | <listitem><para><emphasis>Overhead:</emphasis> | ||
463 | Use the | ||
464 | <link linkend='var-IMAGE_OVERHEAD_FACTOR'><filename>IMAGE_OVERHEAD_FACTOR</filename></link> | ||
465 | variable to define the multiplier that the build system | ||
466 | applies to the initial image size, which is 1.3 by | ||
467 | default.</para></listitem> | ||
468 | <listitem><para><emphasis>Additional Free Space:</emphasis> | ||
469 | Use the | ||
470 | <link linkend='var-IMAGE_ROOTFS_EXTRA_SPACE'><filename>IMAGE_ROOTFS_EXTRA_SPACE</filename></link> | ||
471 | variable to add additional free space to the image. | ||
472 | The build system adds this space to the image after | ||
473 | it determines its | ||
474 | <filename>IMAGE_ROOTFS_SIZE</filename>. | ||
475 | </para></listitem> | ||
476 | </itemizedlist> | ||
477 | </para> | ||
478 | </answer> | ||
479 | </qandaentry> | ||
480 | |||
481 | <qandaentry> | ||
482 | <question> | ||
483 | <para> | ||
484 | Why don't you support directories with spaces in the pathnames? | ||
485 | </para> | ||
486 | </question> | ||
487 | <answer> | ||
488 | <para> | ||
489 | The Yocto Project team has tried to do this before but too | ||
490 | many of the tools the OpenEmbedded build system depends on, | ||
491 | such as <filename>autoconf</filename>, break when they find | ||
492 | spaces in pathnames. | ||
493 | Until that situation changes, the team will not support spaces | ||
494 | in pathnames. | ||
495 | </para> | ||
496 | </answer> | ||
497 | </qandaentry> | ||
498 | |||
499 | <qandaentry> | ||
500 | <question> | ||
501 | <para> | ||
502 | How do I use an external toolchain? | ||
503 | </para> | ||
504 | </question> | ||
505 | <answer> | ||
506 | <para> | ||
507 | The toolchain configuration is very flexible and customizable. | ||
508 | It is primarily controlled with the | ||
509 | <filename><link linkend='var-TCMODE'>TCMODE</link></filename> | ||
510 | variable. | ||
511 | This variable controls which <filename>tcmode-*.inc</filename> | ||
512 | file to include from the | ||
513 | <filename>meta/conf/distro/include</filename> directory within | ||
514 | the | ||
515 | <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>. | ||
516 | </para> | ||
517 | |||
518 | <para> | ||
519 | The default value of <filename>TCMODE</filename> is "default", | ||
520 | which tells the OpenEmbedded build system to use its internally | ||
521 | built toolchain (i.e. <filename>tcmode-default.inc</filename>). | ||
522 | However, other patterns are accepted. | ||
523 | In particular, "external-*" refers to external toolchains. | ||
524 | One example is the Sourcery G++ Toolchain. | ||
525 | The support for this toolchain resides in the separate | ||
526 | <filename>meta-sourcery</filename> layer at | ||
527 | <ulink url='http://github.com/MentorEmbedded/meta-sourcery/'></ulink>. | ||
528 | </para> | ||
529 | |||
530 | <para> | ||
531 | In addition to the toolchain configuration, you also need a | ||
532 | corresponding toolchain recipe file. | ||
533 | This recipe file needs to package up any pre-built objects in | ||
534 | the toolchain such as <filename>libgcc</filename>, | ||
535 | <filename>libstdcc++</filename>, any locales, and | ||
536 | <filename>libc</filename>. | ||
537 | </para> | ||
538 | </answer> | ||
539 | </qandaentry> | ||
540 | |||
541 | <qandaentry> | ||
542 | <question> | ||
543 | <para id='how-does-the-yocto-project-obtain-source-code-and-will-it-work-behind-my-firewall-or-proxy-server'> | ||
544 | How does the OpenEmbedded build system obtain source code and | ||
545 | will it work behind my firewall or proxy server? | ||
546 | </para> | ||
547 | </question> | ||
548 | <answer> | ||
549 | <para> | ||
550 | The way the build system obtains source code is highly | ||
551 | configurable. | ||
552 | You can setup the build system to get source code in most | ||
553 | environments if HTTP transport is available. | ||
554 | </para> | ||
555 | <para> | ||
556 | When the build system searches for source code, it first | ||
557 | tries the local download directory. | ||
558 | If that location fails, Poky tries | ||
559 | <link linkend='var-PREMIRRORS'><filename>PREMIRRORS</filename></link>, | ||
560 | the upstream source, and then | ||
561 | <link linkend='var-MIRRORS'><filename>MIRRORS</filename></link> | ||
562 | in that order. | ||
563 | </para> | ||
564 | <para> | ||
565 | Assuming your distribution is "poky", the OpenEmbedded build | ||
566 | system uses the Yocto Project source | ||
567 | <filename>PREMIRRORS</filename> by default for SCM-based | ||
568 | sources, upstreams for normal tarballs, and then falls back | ||
569 | to a number of other mirrors including the Yocto Project | ||
570 | source mirror if those fail. | ||
571 | </para> | ||
572 | <para> | ||
573 | As an example, you could add a specific server for the | ||
574 | build system to attempt before any others by adding something | ||
575 | like the following to the <filename>local.conf</filename> | ||
576 | configuration file: | ||
577 | <literallayout class='monospaced'> | ||
578 | PREMIRRORS_prepend = "\ | ||
579 | git://.*/.* http://www.yoctoproject.org/sources/ \n \ | ||
580 | ftp://.*/.* http://www.yoctoproject.org/sources/ \n \ | ||
581 | http://.*/.* http://www.yoctoproject.org/sources/ \n \ | ||
582 | https://.*/.* http://www.yoctoproject.org/sources/ \n" | ||
583 | </literallayout> | ||
584 | </para> | ||
585 | <para> | ||
586 | These changes cause the build system to intercept Git, FTP, | ||
587 | HTTP, and HTTPS requests and direct them to the | ||
588 | <filename>http://</filename> sources mirror. | ||
589 | You can use <filename>file://</filename> URLs to point to | ||
590 | local directories or network shares as well. | ||
591 | </para> | ||
592 | <para> | ||
593 | Aside from the previous technique, these options also exist: | ||
594 | <literallayout class='monospaced'> | ||
595 | BB_NO_NETWORK = "1" | ||
596 | </literallayout> | ||
597 | This statement tells BitBake to issue an error instead of | ||
598 | trying to access the Internet. | ||
599 | This technique is useful if you want to ensure code builds | ||
600 | only from local sources. | ||
601 | </para> | ||
602 | <para> | ||
603 | Here is another technique: | ||
604 | <literallayout class='monospaced'> | ||
605 | BB_FETCH_PREMIRRORONLY = "1" | ||
606 | </literallayout> | ||
607 | This statement limits the build system to pulling source | ||
608 | from the <filename>PREMIRRORS</filename> only. | ||
609 | Again, this technique is useful for reproducing builds. | ||
610 | </para> | ||
611 | <para> | ||
612 | Here is another technique: | ||
613 | <literallayout class='monospaced'> | ||
614 | BB_GENERATE_MIRROR_TARBALLS = "1" | ||
615 | </literallayout> | ||
616 | This statement tells the build system to generate mirror | ||
617 | tarballs. | ||
618 | This technique is useful if you want to create a mirror server. | ||
619 | If not, however, the technique can simply waste time during | ||
620 | the build. | ||
621 | </para> | ||
622 | <para> | ||
623 | Finally, consider an example where you are behind an | ||
624 | HTTP-only firewall. | ||
625 | You could make the following changes to the | ||
626 | <filename>local.conf</filename> configuration file as long as | ||
627 | the <filename>PREMIRRORS</filename> server is current: | ||
628 | <literallayout class='monospaced'> | ||
629 | PREMIRRORS_prepend = "\ | ||
630 | ftp://.*/.* http://www.yoctoproject.org/sources/ \n \ | ||
631 | http://.*/.* http://www.yoctoproject.org/sources/ \n \ | ||
632 | https://.*/.* http://www.yoctoproject.org/sources/ \n" | ||
633 | BB_FETCH_PREMIRRORONLY = "1" | ||
634 | </literallayout> | ||
635 | These changes would cause the build system to successfully | ||
636 | fetch source over HTTP and any network accesses to anything | ||
637 | other than the <filename>PREMIRRORS</filename> would fail. | ||
638 | </para> | ||
639 | <para> | ||
640 | The build system also honors the standard shell environment | ||
641 | variables <filename>http_proxy</filename>, | ||
642 | <filename>ftp_proxy</filename>, | ||
643 | <filename>https_proxy</filename>, and | ||
644 | <filename>all_proxy</filename> to redirect requests through | ||
645 | proxy servers. | ||
646 | </para> | ||
647 | <note> | ||
648 | You can find more information on the | ||
649 | "<ulink url='&YOCTO_WIKI_URL;/wiki/Working_Behind_a_Network_Proxy'>Working Behind a Network Proxy</ulink>" | ||
650 | Wiki page. | ||
651 | </note> | ||
652 | </answer> | ||
653 | </qandaentry> | ||
654 | |||
655 | <qandaentry> | ||
656 | <question> | ||
657 | <para> | ||
658 | Can I get rid of build output so I can start over? | ||
659 | </para> | ||
660 | </question> | ||
661 | <answer> | ||
662 | <para> | ||
663 | Yes - you can easily do this. | ||
664 | When you use BitBake to build an image, all the build output | ||
665 | goes into the directory created when you run the | ||
666 | build environment setup script (i.e. | ||
667 | <link linkend='structure-core-script'><filename>&OE_INIT_FILE;</filename></link> | ||
668 | or | ||
669 | <link linkend='structure-memres-core-script'><filename>oe-init-build-env-memres</filename></link>). | ||
670 | By default, this <ulink url='&YOCTO_DOCS_DEV_URL;#build-directory'>Build Directory</ulink> | ||
671 | is named <filename>build</filename> but can be named | ||
672 | anything you want. | ||
673 | </para> | ||
674 | |||
675 | <para> | ||
676 | Within the Build Directory, is the <filename>tmp</filename> | ||
677 | directory. | ||
678 | To remove all the build output yet preserve any source code or | ||
679 | downloaded files from previous builds, simply remove the | ||
680 | <filename>tmp</filename> directory. | ||
681 | </para> | ||
682 | </answer> | ||
683 | </qandaentry> | ||
684 | |||
685 | |||
686 | </qandaset> | ||
687 | </chapter> | ||
688 | <!-- | ||
689 | vim: expandtab tw=80 ts=4 | ||
690 | --> | ||