3 The guidelines in this file are the ideals; it's better to send a
4 not-fully-following-guidelines patch than no patch at all, though. We
5 can always polish it up.
7 ## Source code and issue tracking
9 Source code and issue tracking for the D-Bus specification and its
10 reference implementation 'dbus' are provided by freedesktop.org Gitlab:
11 <https://gitlab.freedesktop.org/dbus/dbus>.
13 ## Reporting security vulnerabilities
15 If you find a security vulnerability that is not known to the public,
16 please report it privately to dbus-security@lists.freedesktop.org
17 or by reporting a Gitlab issue at
18 https://gitlab.freedesktop.org/dbus/dbus/issues/new and marking it
23 The D-Bus mailing list is dbus@lists.freedesktop.org; discussion of
24 protocol enhancements, new implementations, etc. should go there.
28 As a freedesktop.org project, dbus follows the Contributor Covenant,
29 found at: https://www.freedesktop.org/wiki/CodeOfConduct
31 Please conduct yourself in a respectful and civilised manner when
32 interacting with community members on mailing lists, IRC, or bug
33 trackers. The community represents the project as a whole, and abusive
34 or bullying behaviour is not tolerated by the project.
38 D-Bus uses Git as its version control system. The main repository is
39 hosted on freedesktop.org Gitlab. To clone D-Bus, execute one of the
42 git clone https://gitlab.freedesktop.org/dbus/dbus.git
43 git clone git@gitlab.freedesktop.org:dbus/dbus.git
45 The second form is the one that allows pushing, but it also requires
46 an SSH account on the server. The first form allows anonymous
51 D-Bus development happens in multiple branches in parallel. The main
52 branches are the current stable branch, with an even minor number (like
53 1.0, 1.2 and 1.4), and the next development branch, with the next odd
54 number. At the time of writing, the stable branch is dbus 1.12.x and
55 the development branch is dbus 1.13.x, leading to a new 1.14.x stable
58 Stable branches are named after the version number itself (`dbus-1.2`,
59 `dbus-1.4`), whereas the development branch is simply known as
62 New features, enhancements, minor bug fixes, and bug fixes that are
63 unusually intrusive should always be based on the `master` branch.
65 Fixes for significant bugs should be developed on the `master` branch
66 and cherry-picked to the most recent stable branch.
68 Depending on the release cycles of various Linux distributions, some
69 older stable branches might continue to receive fixes for security
70 vulnerabilities (and sometimes major non-security bugs) for a time.
71 These are announced on the D-Bus mailing list.
73 Old development branches are not supported at all, and will not receive
74 any bug fixes - not even for security vulnerabilities. Please do not
75 use a development branch like 1.13.x in your OS distribution, unless
76 you can guarantee that you will upgrade to the next stable branch such
77 as 1.14.x when it becomes available.
81 If you are making changes that you wish to be incorporated upstream,
82 please do as small commits to your local git tree that are individually
83 correct, so there is a good history of your changes.
85 The first line of the commit message should be a single sentence that
86 describes the change, optionally with a prefix that identifies the
87 area of the code that is affected.
89 The body of the commit message should describe what the patch changes
90 and why, and also note any particular side effects. This shouldn't be
91 empty on most of the cases. It shouldn't take a lot of effort to write a
92 commit message for an obvious change, so an empty commit message body is
93 only acceptable if the questions "What?" and "Why?" are already answered
94 on the one-line summary.
96 The lines of the commit message should have at most 76 characters,
97 to cope with the way git log presents them.
99 See [notes on commit messages](https://who-t.blogspot.com/2009/12/on-commit-messages.html),
100 [A Note About Git Commit Messages](https://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
101 or [How to Write a Git Commit Message](https://chris.beams.io/posts/git-commit/)
102 for recommended reading on writing high-quality commit messages.
104 Your patches should also include a Signed-off-by line with your name and
105 email address, indicating that your contribution follows the [Developer's
106 Certificate of Origin](https://developercertificate.org/). If you're
107 not the patch's original author, you should also gather S-o-b's by
108 them (and/or whomever gave the patch to you.) The significance of this
109 is that it certifies that you created the patch, that it was created
110 under an appropriate open source license, or provided to you under those
111 terms. This lets us indicate a chain of responsibility for the copyright
114 We won't reject patches that lack S-o-b, but it is strongly recommended.
116 ### Sending a merge request
118 When you consider your changes to be ready for merging to mainline:
120 * create a personal fork of <https://gitlab.freedesktop.org/dbus/dbus>
121 on freedesktop.org Gitlab
122 * push your changes to your personal fork as a branch
123 * create a merge request at
124 <https://gitlab.freedesktop.org/dbus/dbus/merge_requests>
126 ### Security guidelines
128 Most of D-Bus is security sensitive. Guidelines related to that:
130 - avoid `memcpy()`, `sprintf()`, `strlen()`, `snprintf()`, `strlcat()`,
131 `strstr()`, `strtok()`, or any of this stuff. Use `DBusString`.
132 If `DBusString` doesn't have the feature you need, add it
135 There are some exceptions, for example
136 if your strings are just used to index a hash table
137 and you don't do any parsing/modification of them, perhaps
138 `DBusString` is wasteful and wouldn't help much. But definitely
139 if you're doing any parsing, reallocation, etc. use `DBusString`.
141 - do not include system headers outside of `dbus-memory.c`,
142 `dbus-sysdeps.c`, and other places where they are already
143 included. This gives us one place to audit all external
144 dependencies on features in libc, etc.
146 - do not use libc features that are "complicated"
147 and may contain security holes. For example, you probably shouldn't
148 try to use `regcomp()` to compile an untrusted regular expression.
149 Regular expressions are just too complicated, and there are many
150 different libc implementations out there.
152 - we need to design the message bus daemon (and any similar features)
153 to use limited privileges, run in a chroot jail, and so on.
155 http://vsftpd.beasts.org/ has other good security suggestions.
159 - Please follow the coding style and indentation of nearby code.
161 - C code uses GNU coding conventions (approximately "gnu" style in
162 Emacs), with GLib-like extensions (e.g. lining up function arguments).
164 - Write docs for all non-static functions and structs and so on. try
165 `doxygen Doxyfile` prior to commit and try not to cause any new
168 - All external interfaces (network protocols, file formats, etc.)
169 should have documented specifications sufficient to allow an
170 alternative implementation to be written. Our implementation should
171 be strict about specification compliance (should not for example
172 heuristically parse a file and accept not-well-formed
173 data). Avoiding heuristics is also important for security reasons;
174 if it looks funny, ignore it (or exit, or disconnect).
178 Please match the existing licensing (a dual-license: AFL-2.1 or GPL-2+,
179 recipient's choice). Entirely new modules can be placed under a more
180 permissive license: to avoid license proliferation, our preferred
181 permissive license is the variant of the MIT/X11 license used by the
182 Expat XML library (for example see the top of tools/ci-build.sh).
186 The primary build system for dbus uses the GNU Autotools suite (Autoconf,
187 Automake and Libtool). This build system is strongly recommended for
188 Unix OS integrators. It can also be used to compile dbus for Windows
189 using the mingw-w64 compiler suite, either by cross-compiling on a Unix
190 system or by using an environment like MSYS2 on Windows.
192 There is also a CMake build system. This is primarily there to make it
193 easier to build dbus on Windows, using either a MSYS2/mingw environment
194 or the MSVC compiler from Microsoft Visual Studio. It can also be used
195 on a GNU/Linux system, but this is not recommended for OS integrators.
197 Changes contributed to dbus must not break the build for either of these
198 build systems. It is OK for the CMake build system to support fewer
199 options, support fewer operating systems, have less test coverage or
200 build fewer non-essential programs, but it must continue to work on at
201 least GNU/Linux and Windows.
203 ### Environment variables
205 These are some of the environment variables that are used by the D-Bus
210 Turns on printing verbose messages. This only works if D-Bus has been
211 compiled with `--enable-verbose-mode`.
213 * `DBUS_MALLOC_FAIL_NTH=n`
215 Can be set to a number, causing every *n*th call to `dbus_alloc` or
216 `dbus_realloc` to fail. This only works if D-Bus has been compiled with
217 `--enable-embedded-tests`.
219 * `DBUS_MALLOC_FAIL_GREATER_THAN=n`
221 Can be set to a number, causing every call to `dbus_alloc` or
222 `dbus_realloc` to fail if the number of bytes to be allocated is greater
223 than the specified number. This only works if D-Bus has been compiled with
224 `--enable-embedded-tests`.
226 * `DBUS_TEST_MALLOC_FAILURES=n`
228 Many of the D-Bus tests will run over and over, once for each `malloc`
229 involved in the test. Each run will fail a different `malloc`, plus some
230 number of `malloc`s following that malloc (because a fair number of bugs
231 only happen if two or more `malloc`s fail in a row, e.g. error recovery
232 that itself involves `malloc`). This environment variable sets the
233 number of consecutive `malloc`s to fail.
235 Here's why you care: If set to 0, then the `malloc` checking is skipped,
236 which makes the test suite a lot faster. Just run with this
237 environment variable unset before you commit.
241 Please try to write test coverage for all new functionality.
242 We have two broad categories of tests.
244 The *modular tests* are enabled by configuring with
245 `--enable-modular-tests`. These mostly use GLib's GTest framework,
246 and are standalone programs that do not affect the contents of the
247 production dbus library and programs. Most of them can be installed
248 alongside the library and programs by configuring with
249 `--enable-installed-tests`.
251 The *embedded tests* are enabled by configuring with
252 `--enable-embedded-tests`. Unlike the modular tests, enabling the
253 embedded tests adds special code to libdbus and dbus-daemon, some of
254 which may harm performance or security. A production version of dbus
255 that will be included in an operating system should never have the
256 embedded tests enabled.
258 If possible, new test coverage should be provided via modular tests,
259 preferably using GLib's GTest framework. `test/dbus-daemon.c` is a good
262 ## Information for maintainers
264 This section is not directly relevant to infrequent contributors.
268 To make a release of D-Bus, do the following:
270 - check out a fresh copy from Git
272 - verify that the libtool versioning/library soname is
273 changed if it needs to be, or not changed if not
275 - update the file NEWS based on the git history
277 - verify that the version number of dbus-specification.xml is
278 changed if it needs to be; if changes have been made, update the
279 release date in that file
281 - update the AUTHORS file with "make update-authors" if necessary
283 - the version number should have major.minor.micro, even
284 if micro is 0, i.e. "1.0.0" and "1.2.0" not "1.0"/"1.2"; the micro
285 version should be even for releases, and odd for intermediate snapshots
287 - "make distcheck" (DO NOT just "make dist" - pass the check!)
289 - if make distcheck fails, fix it.
291 - once distcheck succeeds, "git commit -a". This is the version
292 of the tree that corresponds exactly to the released tarball.
294 - tag the tree with "git tag -s -m 'Released X.Y.Z' dbus-X.Y.Z"
295 where X.Y.Z is the version of the release. If you can't sign
296 then simply created an unsigned annotated tag:
297 "git tag -a -m 'Released X.Y.Z' dbus-X.Y.Z".
299 - bump the version number up in configure.ac (so the micro version is odd),
300 and commit it. Make sure you do this *after* tagging the previous
301 release! The idea is that git has a newer version number
302 than anything released. Similarly, bump the version number of
303 dbus-specification.xml and set the release date to "(not finalized)".
305 - merge the branch you've released to the chronologically-later
306 branch (usually "master"). You'll probably have to fix a merge
307 conflict in configure.ac (the version number).
309 - push your changes and the tag to the central repository with
310 git push origin master dbus-X.Y dbus-X.Y.Z
312 - scp your tarball to freedesktop.org server and copy it to
313 dbus.freedesktop.org:/srv/dbus.freedesktop.org/www/releases/dbus/dbus-X.Y.Z.tar.gz.
314 This should be possible if you're in group "dbus"
316 - Update the online documentation with `make -C doc maintainer-upload-docs`.
318 - update the wiki page http://www.freedesktop.org/Software/dbus by
319 adding the new release under the Download heading. Then, cut the
320 link and changelog for the previous that was there.
322 - post to dbus@lists.freedesktop.org announcing the release.
324 ### Making a ".0" stable release
326 We create a branch for each stable release. The branch name should be
327 dbus-X.Y which is a branch that has releases versioned X.Y.Z;
328 changes on a stable branch should be limited to significant bug fixes.
330 Because we won't make minor changes like keeping up with the latest
331 deprecations on a stable branch, stable branches should turn off the
332 gcc warning for deprecated declarations (e.g. see commit 4ebb275ab7).
334 Be extra-careful not to merge master (or any branch based on master) into a
341 and upload the branch tag to the server:
343 git push origin dbus-X.Y
345 To develop in this branch:
347 git checkout dbus-X.Y
351 The commit rules are approximately these:
353 - Fixes that don't affect API or protocol can be committed
354 if any one qualified reviewer other than patch author
357 - For fixes that do affect API or protocol, two people
358 in the reviewer group have to review and approve the commit.
360 - If there's a live unresolved controversy about a change,
361 don't commit it while the argument is still raging.
363 - At their discretion, members of the reviewer group may also commit
364 branches/patches under these conditions:
366 - the branch does not add or change API, ABI or wire-protocol
368 - the branch solves a known problem and is covered by the regression tests
370 - there are no objections from the rest of the review group within
371 a week of the merge request being opened
373 - the committer gets a positive review on the merge request from someone
374 they consider qualified to review the change (e.g. a colleague with D-Bus
375 experience; not necessarily a member of the reviewer group)
377 - Regardless of reviews, to commit a patch:
379 - `make check` must pass
380 - the test suite must be extended to cover the new code
381 as much as reasonably feasible (see Tests above)
382 - the patch has to follow the portability, security, and
384 - the patch should as much as reasonable do one thing,
385 not many unrelated changes
387 No reviewer should approve a patch without these attributes, and
388 failure on these points is grounds for reverting the patch.
390 The reviewer group that can approve patches consists of the members
391 of <https://gitlab.freedesktop.org/dbus/dbus/project_members> with
392 "Maintainer" or "Owner" status.