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Mark Whitley3b565cd2001-03-02 19:14:25 +00001Contributing To Busybox
2=======================
3
4This document describes what you need to do to contribute to Busybox, where
5you can help, guidelines on testing, and how to submit a well-formed patch
6that is more likely to be accepted.
7
8The Busybox home page is at: http://busybox.lineo.com
9
10
11
12Pre-Contribution Checklist
13--------------------------
14
15So you want to contribute to Busybox, eh? Great, wonderful, glad you want to
16help. However, before you dive in, headlong and hotfoot, there are some things
17you need to do:
18
19
20Checkout the Latest Code from CVS
21~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
22
23This is a necessary first step. Please do not try to work with the last
Mark Whitley0b4d73a2001-03-22 22:59:33 +000024released version, as there is a good chance that somebody has already fixed
25the bug you found. Somebody might have even added the feature you had in mind.
26Don't make your work obsolete before you start!
Mark Whitley3b565cd2001-03-02 19:14:25 +000027
28For information on how to check out Busybox from CVS, please look at the
29following links:
30
31 http://oss.lineo.com/cvs_anon.html
32 http://oss.lineo.com/cvs_howto.html
33
34
35Read the Mailing List
36~~~~~~~~~~~~~~~~~~~~~
37
38No one is required to read the entire archives of the mailing list, but you
39should at least read up on what people have been talking about lately. If
40you've recently discovered a problem, chances are somebody else has too. If
41you're the first to discover a problem, post a message and let the rest of us
42know.
43
44Archives can be found here:
45
46 http://opensource.lineo.com/lists/busybox/
47
Eric Andersen77d92682001-05-23 20:32:09 +000048If you have a serious interest in Busybox, i.e., you are using it day-to-day or
Mark Whitley0b4d73a2001-03-22 22:59:33 +000049as part of an embedded project, it would be a good idea to join the mailing
50list.
Mark Whitley3b565cd2001-03-02 19:14:25 +000051
52A web-based sign-up form can be found here:
53
54 http://opensource.lineo.com/mailman/listinfo/busybox
55
56
57Coordinate with the Applet Maintainer
58~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
59
60Some (not all) of the applets in Busybox are "owned" by a maintainer who has
61put significant effort into it and is probably more familiar with it than
62others. To find the maintainer of an applet, look at the top of the .c file
Mark Whitley0b4d73a2001-03-22 22:59:33 +000063for a name following the word 'Copyright' or 'Written by' or 'Maintainer'.
Mark Whitley3b565cd2001-03-02 19:14:25 +000064
65Before plunging ahead, it's a good idea to send a message to the mailing list
66that says: "Hey, I was thinking about adding the 'transmogrify' feature to the
67'foo' applet. Would this be useful? Is anyone else working on it?" You might
68want to CC the maintainer (if any) with your question.
69
70
71
72Areas Where You Can Help
73------------------------
74
75Busybox can always use improvement! If you're looking for ways to help, there
76there are a variety of areas where you could help.
77
78
79What Busybox Doesn't Need
80~~~~~~~~~~~~~~~~~~~~~~~~~
81
82Before listing the areas where you _can_ help, it's worthwhile to mention the
83areas where you shouldn't bother. While Busybox strives to be the "Swiss Army
84Knife" of embedded Linux, there are some applets that will not be accepted:
85
86 - Any filesystem manipulation tools: Busybox is filesystem independent and
87 we do not want to start adding mkfs/fsck tools for every (or any)
88 filesystem under the sun. (fsck_minix.c and mkfs_minix.c are living on
Mark Whitley0b4d73a2001-03-22 22:59:33 +000089 borrowed time.) There are far too many of these tools out there. Use
90 the upstream version. Not everything has to be part of Busybox.
Mark Whitley3b565cd2001-03-02 19:14:25 +000091
92 - Any partitioning tools: Partitioning a device is typically done once and
93 only once, and tools which do this generally do not need to reside on the
94 target device (esp a flash device). If you need a partitioning tool, grab
95 one (such as fdisk, sfdisk, or cfdisk from util-linux) and use that, but
96 don't try to merge it into busybox. These are nasty and complex and we
97 don't want to maintain them.
98
99 - Any disk, device, or media-specific tools: Use the -utils or -tools package
100 that was designed for your device; don't try to shoehorn them into Busybox.
101
102 - Any architecture specific tools: Busybox is (or should be) architecture
103 independent. Do not send us tools that cannot be used across multiple
104 platforms / arches.
105
Mark Whitley0b4d73a2001-03-22 22:59:33 +0000106 - Any daemons that are not essential to basic system operation. To date, only
107 syslogd and klogd meet this requirement. We do not need a web server, an
108 ftp daemon, a dhcp server, a mail transport agent or a dns resolver. If you
109 need one of those, you are welcome to ask the folks on the mailing list for
110 recommendations, but please don't bloat up Busybox with any of these.
111
Mark Whitley3b565cd2001-03-02 19:14:25 +0000112
113Bug Reporting
114~~~~~~~~~~~~~
115
116If you find a bug in Busybox, you can send a bug report to our bug tracking
117system (homepage: http://bugs.lineo.com). Instructions on how to send a bug
118report to the tracking system can be found at:
119
120 http://bugs.lineo.com/Reporting.html
121
122The README file that comes with Busybox also describes how to submit a bug.
123
Mark Whitley0b4d73a2001-03-22 22:59:33 +0000124A well-written bug report should include a transcript of a shell session that
Mark Whitley3b565cd2001-03-02 19:14:25 +0000125demonstrates the bad behavior and enables anyone else to duplicate the bug on
Mark Whitley0b4d73a2001-03-22 22:59:33 +0000126their own machine. The following is such an example:
127
128 When I execute Busybox 'date' it produces unexpected results.
129
130 This is using GNU date:
131 $ date
132 Wed Mar 21 14:19:41 MST 2001
133
134 This is using Busybox date:
135 $ date
136 codswaddle
Mark Whitley3b565cd2001-03-02 19:14:25 +0000137
138
139Bug Triage
140~~~~~~~~~~
141
142Validating and confirming bugs is nearly as important as reporting them in the
143first place. It is valuable to know if a bug can be duplicated on a different
144machine, on a different filesystem, on a different architecture, with a
145different C library, and so forth.
146
147To see a listing of all the bugs currently filed against Busybox, look here:
148
149 http://bugs.lineo.com/db/pa/lbusybox.html
150
151If you have comments to add to a bug (can / can't duplicate, think a bug
152should be closed / reopened), please send it to [bugnumber]@bugs.lineo.com.
153The message you send will automatically be forwarded to the mailing list for
154all to see.
155
156
157Write Documentation
158~~~~~~~~~~~~~~~~~~~
159
160Chances are, documentation in Busybox is either missing or needs improvement.
161Either way, help is welcome.
162
163Work is being done to automatically generate documentation from sources,
164especially from the usage.h file. If you want to correct the documentation,
165please make changes to the pre-generation parts, rather than the generated
166documentation. [More to come on this later...]
167
168It is preferred that modifications to documentation be submitted in patch
169format (more on this below), but we're a little more lenient when it comes to
170docs. You could, for example, just say "after the listing of the mount
171options, the following example would be helpful..."
172
173
174Consult Existing Sources
175~~~~~~~~~~~~~~~~~~~~~~~~
176
177For a quick listing of "needs work" spots in the sources, cd into the Busybox
178directory and run the following:
179
180 for i in TODO FIXME XXX; do grep $i *.[ch]; done
181
182This will show all of the trouble spots or 'questionable' code. Pick a spot,
183any spot, these are all invitations for you to contribute.
184
185
186Consult The Bug-Tracking System
187~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
188
189Head to: http://bugs.lineo.com/db/pa/lBusybox.html and look at the bugs on
190there. Pick one you think you can fix, and fix it. If it's a wishlist item and
191someone's requesting a new feature, take a stab at adding it. Everything
192previously said about "reading the mailing list" and "coordinating with the
193applet maintainer" still applies.
194
195
196Add a New Applet
197~~~~~~~~~~~~~~~~
198
199If you want to add a new applet to Busybox, we'd love to see it. However,
200before you write any code, please ask beforehand on the mailing list something
201like "Do you think applet 'foo' would be useful in Busybox?" or "Would you
202guys accept applet 'foo' into Busybox if I were to write it?" If the answer is
203"no" by the folks on the mailing list, then you've saved yourself some time.
204Conversely, you could get some positive responses from folks who might be
205interested in helping you implement it, or can recommend the best approach.
206Perhaps most importantly, this is your way of calling "dibs" on something and
207avoiding duplication of effort.
208
209Also, before you write a line of code, please read the 'new-applet-HOWTO.txt'
210file in the docs/ directory.
211
212
213Janitorial Work
214~~~~~~~~~~~~~~~
215
216These are dirty jobs, but somebody's gotta do 'em.
217
Mark Whitley9ead6892001-03-03 00:44:55 +0000218 - Converting applets to use getopt() for option processing. Type 'grep -L
219 getopt *.c' to get a listing of the applets that currently don't use
220 getopt. If a .c file processes no options, it should have a line that
221 reads: /* no options, no getopt */ somewhere in the file.
222
Mark Whitley6c563bc2001-03-06 23:16:13 +0000223 - Replace any "naked" calls to malloc, calloc, realloc, str[n]dup, fopen with
224 the x* equivalents found in utility.c.
225
Mark Whitley3b565cd2001-03-02 19:14:25 +0000226 - Security audits:
227 http://www.securityfocus.com/frames/?content=/forums/secprog/secure-programming.html
228
229 - Synthetic code removal: http://www.perl.com/pub/2000/06/commify.html - This
230 is very Perl-specific, but the advice given in here applies equally well to
231 C.
232
233 - C library funciton use audits: Verifying that functions are being used
234 properly (called with the right args), replacing unsafe library functions
235 with safer versions, making sure return codes are being checked, etc.
236
237 - Where appropriate, replace preprocessor defined macros and values with
238 compile-time equivalents.
239
Mark Whitley0b4d73a2001-03-22 22:59:33 +0000240 - Style guide compliance. See: docs/style-guide.txt
241
242 - Add testcases to tests/testcases.
243
Mark Whitley3b565cd2001-03-02 19:14:25 +0000244 - Makefile improvements:
245 http://www.canb.auug.org.au/~millerp/rmch/recu-make-cons-harm.html
246 (I think the recursive problems are pretty much taken care of at this point, non?)
247
248 - "Ten Commandments" compliance: (this is a "maybe", certainly not as
249 important as any of the previous items.)
250 http://web.onetelnet.ch/~twolf/tw/c/ten_commandments.html
251
252Other useful links:
253
254 - the comp.lang.c FAQ: http://web.onetelnet.ch/~twolf/tw/c/index.html#Sources
255
256
257
258Submitting Patches To Busybox
259-----------------------------
260
261Here are some guidelines on how to submit a patch to Busybox.
262
263
264Making A Patch
265~~~~~~~~~~~~~~
266
267If you've got anonymous CVS access set up, making a patch is simple. Just make
268sure you're in the busybox/ directory and type 'cvs diff -bwu > mychanges.patch'.
269You can send the resulting .patch file to the mailing list with a description
270of what it does. (But not before you test it! See the next section for some
271guidelines.) It is preferred that patches be sent as attachments, but it is
272not required.
273
274Also, feel free to help test other people's patches and reply to them with
275comments. You can apply a patch by saving it into your busybox/ directory and
276typing 'patch < mychanges.patch'. Then you can recompile, see if it runs, test
277if it works as advertised, and post your findings to the mailing list.
278
279NOTE: Please do not include extraneous or irrelevant changes in your patches.
280Please do not try to "bundle" two patches together into one. Make single,
281discreet changes on a per-patch basis. Sometimes you need to make a patch that
282touches code in many places, but these kind of patches are rare and should be
283coordinated with a maintainer.
284
285
286Testing Guidelines
287~~~~~~~~~~~~~~~~~~
288
289It's considered good form to test your new feature before you submit a patch
290to the mailing list, and especially before you commit a change to CVS. Here
291are some guidelines on how to test your changes.
292
293 - Always test Busybox applets against GNU counterparts and make sure the
294 behavior / output is identical between the two.
295
296 - Try several different permutations and combinations of the features you're
Eric Andersen77d92682001-05-23 20:32:09 +0000297 adding (i.e., different combinations of command-line switches) and make sure
Mark Whitley3b565cd2001-03-02 19:14:25 +0000298 they all work; make sure one feature does not interfere with another.
299
300 - Make sure you test compiling against the source both with the feature
301 turned on and turned off in Config.h and make sure Busybox compiles cleanly
302 both ways.
303
304 - Run the multibuild.pl script in the tests directory and make sure
305 everything checks out OK. (Do this from within the busybox/ directory by
306 typing: 'tests/multibuild.pl'.)
307
308
309Making Sure Your Patch Doesn't Get Lost
310~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
311
312If you don't want your patch to be lost or forgotten, send it to the bug
313tracking system (http://bugs.lineo.com). You do this by emailing your patch in
314a message to submit@bugs.lineo.com with a subject line something like this:
315
316 [PATCH] - Adds "transmogrify" feature to "foo"
317
318In the body, you should have a pseudo-header that looks like the following:
319
320 Package: busybox
321 Version: v0.50pre (or whatever the current version is)
322 Severity: wishlist
323
324The remainder of the body should read along these lines:
325
326 This patch adds the "transmogrify" feature to the "foo" applet. I have
327 tested this on [arch] system(s) and it works. I have tested it against the
328 GNU counterparts and the outputs are identical. I have run the scripts in
329 the 'tests' directory and nothing breaks.
330
331Detailed instructions on how to submit a bug to the tracking system are at:
332
333 http://bugs.lineo.com/Reporting.html
334
Mark Whitley5b8939b2001-03-27 21:20:05 +0000335If you have a patch that will fix and close a reported bug, please send a
336message to [bugnumber]@bugs.lineo.com with your patch attached. It will catch
337people's attention if you have a subject line like the following:
338
339 [PATCH INCLUDED] - Fix attached, please apply and close this bug
340
Mark Whitley3b565cd2001-03-02 19:14:25 +0000341
342
343Improving Your Chances of Patch Acceptance
344------------------------------------------
345
346Even after you send a brilliant patch to the mailing list, sometimes it can go
347unnoticed, un-replied-to, and sometimes (sigh) even lost. This is an
348unfortunate fact of life, but there are steps you can take to help your patch
349get noticed and convince a maintainer that it should be added:
350
351
352Be Succinct
353~~~~~~~~~~~
354
355A patch that includes small, isolated, obvious changes is more likely to be
356accepted than a patch that touches code in lots of different places or makes
357sweeping, dubious changes.
358
359
360Back It Up
361~~~~~~~~~~
362
363Hard facts on why your patch is better than the existing code will go a long
364way toward convincing maintainers that your patch should be included.
365Specifically, patches are more likely to be accepted if they are provably more
366correct, smaller, faster, simpler, or more maintainable than the existing
367code.
368
369Conversely, any patch that is supported with nothing more than "I think this
370would be cool" or "this patch is good because I say it is and I've got a Phd
371in Computer Science" will likely be ignored.
372
373
374Follow The Style Guide
375~~~~~~~~~~~~~~~~~~~~~~
376
377It's considered good form to abide by the established coding style used in a
378project; Busybox is no exception. We have gone so far as to delineate the
379"elements of Busybox style" in the file docs/style-guide.txt. Please follow
380them.
381
382
383Work With Someone Else
384~~~~~~~~~~~~~~~~~~~~~~
385
386Working on a patch in isolation is less effective than working with someone
387else for a variety of reasons. If another Busybox user is interested in what
388you're doing, then it's two (or more) voices instead of one that can petition
389for inclusion of the patch. You'll also have more people that can test your
390changes, or even offer suggestions on better approaches you could take.
391
392Getting other folks interested follows as a natural course if you've received
393responses from queries to applet maintainer or positive responses from folks
394on the mailing list.
395
396We've made strident efforts to put a useful "collaboration" infrastructure in
397place in the form of mailing lists, the bug tracking system, and CVS. Please
398use these resources.
399
400
Mark Whitley5b8939b2001-03-27 21:20:05 +0000401Send Patches to the Bug Tracking System
402~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
403
404This was mentioned above in the "Making Sure Your Patch Doesn't Get Lost"
405section, but it is worth mentioning again. A patch sent to the mailing list
406might be unnoticed and forgotten. A patch sent to the bug tracking system will
407be stored and closely connected to the bug it fixes.
408
409
Mark Whitley3b565cd2001-03-02 19:14:25 +0000410Be Polite
411~~~~~~~~~
412
413The old saying "You'll catch more flies with honey than you will with vinegar"
414applies when submitting patches to the mailing list for approval. The way you
415present your patch is sometimes just as important as the actual patch itself
416(if not more so). Being rude to the maintainers is not an effective way to
417convince them that your patch should be included; it will likely have the
418opposite effect.
419
420
421
Mark Whitley0b4d73a2001-03-22 22:59:33 +0000422Committing Changes to CVS
423-------------------------
424
425If you submit several patches that demonstrate that you are a skilled and wise
426coder, you may be invited to become a committer, thus enabling you to commit
427changes directly to CVS. This is nice because you don't have to wait for
428someone else to commit your change for you, you can just do it yourself.
429
430But note that this is a priviledge that comes with some responsibilities. You
431should test your changes before you commit them. You should also talk to an
432applet maintainer before you make any kind of sweeping changes to somebody
433else's code. Big changes should still go to the mailing list first. Remember,
434being wise, polite, and discreet is more important than being clever.
435
436
437When To Commit
438~~~~~~~~~~~~~~
439
440Generally, you should feel free to commit a change if:
441
442 - Your changes are small and don't touch many files
443 - You are fixing a bug
444 - Somebody has told you that it's okay
445 - It's obviously the Right Thing
446
447The more of the above are true, the better it is to just commit a change
448directly to CVS.
449
450
451When Not To Commit
452~~~~~~~~~~~~~~~~~~
453
454Even if you have commit rights, you should probably still post a patch to the
455mailing list if:
456
457 - Your changes are broad and touch many different files
458 - You are adding a feature
Eric Andersen77d92682001-05-23 20:32:09 +0000459 - Your changes are speculative or experimental (i.e., trying a new algorithm)
Mark Whitley0b4d73a2001-03-22 22:59:33 +0000460 - You are not the maintainer and your changes make the maintainer cringe
461
462The more of the above are true, the better it is to post a patch to the
463mailing list instead of committing.
464
465
466
Mark Whitley3b565cd2001-03-02 19:14:25 +0000467Final Words
468-----------
469
470If all of this seems complicated, don't panic, it's really not that tough. If
471you're having difficulty following some of the steps outlined in this
472document don't worry, the folks on the Busybox mailing list are a fairly
473good-natured bunch and will work with you to help get your patches into shape
474or help you make contributions.
475
Mark Whitley3b565cd2001-03-02 19:14:25 +0000476