dbus/HACKING - nest-cam/4320010/dbus - Git at Google

 The guidelines in this file are the ideals; it's better to send a
 not-fully-following-guidelines patch than no patch at all, though.  We
 can always polish it up.

 Mailing list
 ===

 The D-Bus mailing list is dbus@lists.freedesktop.org; discussion
 of patches, etc. should go there.

 Security
 ===

 Most of D-Bus is security sensitive.  Guidelines related to that:

  - avoid memcpy(), sprintf(), strlen(), snprintf, strlcat(),
    strstr(), strtok(), or any of this stuff. Use DBusString.
    If DBusString doesn't have the feature you need, add it
    to DBusString.

    There are some exceptions, for example
    if your strings are just used to index a hash table
    and you don't do any parsing/modification of them, perhaps
    DBusString is wasteful and wouldn't help much. But definitely
    if you're doing any parsing, reallocation, etc. use DBusString.

  - do not include system headers outside of dbus-memory.c,
    dbus-sysdeps.c, and other places where they are already
    included. This gives us one place to audit all external
    dependencies on features in libc, etc.

  - do not use libc features that are "complicated"
    and may contain security holes. For example, you probably shouldn't
    try to use regcomp() to compile an untrusted regular expression.
    Regular expressions are just too complicated, and there are many
    different libc's out there.

  - we need to design the message bus daemon (and any similar features)
    to use limited privileges, run in a chroot jail, and so on.

 http://vsftpd.beasts.org/ has other good security suggestions.

 Coding Style
 ===

  - The C library uses GNU coding conventions, with GLib-like
    extensions (e.g. lining up function arguments). The
    Qt wrapper uses KDE coding conventions.

  - Write docs for all non-static functions and structs and so on. try
    "doxygen Doxyfile" prior to commit and be sure there are no
    warnings printed.

  - All external interfaces (network protocols, file formats, etc.)
    should have documented specifications sufficient to allow an
    alternative implementation to be written. Our implementation should
    be strict about specification compliance (should not for example
    heuristically parse a file and accept not-well-formed
    data). Avoiding heuristics is also important for security reasons;
    if it looks funny, ignore it (or exit, or disconnect).

 Development
 ===

 D-Bus uses Git as its version control system. The main repository is
 hosted at git.freedesktop.org/dbus/dbus. To clone D-Bus, execute the
 following command:

     git clone git://git.freedesktop.org/dbus/dbus
 OR
     git clone git.freedesktop.org:dbus/dbus

 The latter form is the one that allows pushing, but it also requires
 an SSH account on the server. The former form allows anonymous
 checkouts.

 D-Bus development happens in two branches in parallel: the current
 stable branch, with an even minor number (like 1.0, 1.2 and 1.4), and
 the next development branch, with the next odd number.

 The stable branch is named after the version number itself (dbus-1.2,
 dbus-1.4), whereas the development branch is simply known as "master".

 When making a change to D-Bus, do the following:

  - check out the earliest branch of D-Bus that makes sense to have
    your change in. If it's a bugfix, it's normally the current stable
    branch; if it's a feature, it's normally the "master" branch. If
    you have an important security fix, you may want to apply to older
    branches too.

  - for large changes:
      if you're developing a new, large feature, it's recommended
      to create a new branch and do your development there. Publish
      your branch at a suitable place and ask others to help you
      develop and test it. Once your feature is considered finalised,
      you may merge it into the "master" branch.

 - for small changes:
     . make your change to the source code
     . execute tests to guarantee that you're not introducing a
       regression. For that, execute: make check
       (if possible, add a new test to check the fix you're
       introducing)
     . commit your change using "git commit"
       in the commit message, write a short sentence describing what
       you did in the first line. Then write a longer description in
       the next paragraph(s).
     . repeat the previous steps if necessary to have multiple commits

  - extract your patches and send to the D-Bus mailing list for
    review or post them to the D-Bus Bugzilla, attaching them to a bug
    report. To extract the patches, execute:
      git format-patch origin/master

  - once your code has been reviewed, you may push it to the Git
    server:
      git push origin my-branch:remote
    OR
      git push origin dbus-X.Y
    OR
      git push origin master
    (consult the Git manual to know which command applies)

  - (Optional) if you've not worked on "master", merge your changes to
    that branch. If you've worked on an earlier branch than the current
    stable, merge your changes upwards towards the stable branch, then
    from there into "master".

     . execute: git checkout master
     . ensure that you have the latest "master" from the server, update
       if you don't
     . execute: git merge dbus-X.Y
     . if you have any conflicts, resolve them, git add the conflicted
       files and then git commit
     . push the "master" branch to the server as well

   Executing this merge is recommended, but not necessary for all
   changes. You should do this step if your bugfix is critical for the
   development in "master", or if you suspect that conflicts will arise
   (you're usually the best person to resolve conflicts introduced by
   your own code), or if it has been too long since the last merge.


 Making a release
 ===

 To make a release of D-Bus, do the following:

  - check out a fresh copy from Git

  - verify that the libtool versioning/library soname is
    changed if it needs to be, or not changed if not

  - update the file NEWS based on the git history

  - verify that the version number of dbus-specification.xml is
    changed if it needs to be; if changes have been made, update the
    release date in that file

  - update the AUTHORS file with "make update-authors" if necessary

  - the version number should have major.minor.micro, even
    if micro is 0, i.e. "1.0.0" and "1.2.0" not "1.0"/"1.2"; the micro
    version should be even for releases, and odd for intermediate snapshots

  - "make distcheck" (DO NOT just "make dist" - pass the check!)

  - if make distcheck fails, fix it.

  - once distcheck succeeds, "git commit -a".  This is the version
    of the tree that corresponds exactly to the released tarball.

  - tag the tree with "git tag -s -m 'Released X.Y.Z' dbus-X.Y.Z"
    where X.Y.Z is the version of the release.  If you can't sign
    then simply created an unsigned annotated tag:
    "git tag -a -m 'Released X.Y.Z' dbus-X.Y.Z".

  - bump the version number up in configure.ac (so the micro version is odd),
    and commit it.  Make sure you do this *after* tagging the previous
    release! The idea is that git has a newer version number
    than anything released. Similarly, bump the version number of
    dbus-specification.xml and set the release date to "(not finalized)".

  - merge the branch you've released to the chronologically-later
    branch (usually "master"). You'll probably have to fix a merge
    conflict in configure.ac (the version number).

  - push your changes and the tag to the central repository with
      git push origin master dbus-X.Y dbus-X.Y.Z

  - scp your tarball to freedesktop.org server and copy it to
    dbus.freedesktop.org:/srv/dbus.freedesktop.org/www/releases/dbus/dbus-X.Y.Z.tar.gz.
    This should be possible if you're in group "dbus"

  - Update the online documentation with `make -C doc maintainer-upload-docs`.

  - update the wiki page http://www.freedesktop.org/Software/dbus by
    adding the new release under the Download heading. Then, cut the
    link and changelog for the previous that was there.

  - update the wiki page
    http://www.freedesktop.org/Software/DbusReleaseArchive pasting the
    previous release. Note that bullet points for each of the changelog
    items must be indented three more spaces to conform to the
    formatting of the other releases there.

  - post to dbus@lists.freedesktop.org announcing the release.


 Making a ".0" stable release
 ===

 We create a branch for each stable release. The branch name should be
 dbus-X.Y which is a branch that has releases versioned X.Y.Z;
 changes on a stable branch should be limited to significant bug fixes.

 Because we won't make minor changes like keeping up with the latest
 deprecations on a stable branch, stable branches should turn off the
 gcc warning for deprecated declarations (e.g. see commit 4ebb275ab7).

 Be extra-careful not to merge master (or any branch based on master) into a
 stable branch.

 To branch:
   git branch dbus-X.Y
 and upload the branch tag to the server:
   git push origin dbus-X.Y

 To develop in this branch:
   git checkout dbus-X.Y

 Environment variables
 ===

 These are the environment variables that are used by the D-Bus client library

 DBUS_VERBOSE=1
 Turns on printing verbose messages. This only works if D-Bus has been
 compiled with --enable-verbose-mode

 DBUS_MALLOC_FAIL_NTH=n
 Can be set to a number, causing every nth call to dbus_alloc or
 dbus_realloc to fail. This only works if D-Bus has been compiled with
 --enable-tests.

 DBUS_MALLOC_FAIL_GREATER_THAN=n
 Can be set to a number, causing every call to dbus_alloc or
 dbus_realloc to fail if the number of bytes to be allocated is greater
 than the specified number. This only works if D-Bus has been compiled with
 --enable-tests.

 DBUS_TEST_MALLOC_FAILURES=n
 Many of the D-Bus tests will run over and over, once for each malloc
 involved in the test. Each run will fail a different malloc, plus some
 number of mallocs following that malloc (because a fair number of bugs
 only happen if two or more mallocs fail in a row, e.g. error recovery
 that itself involves malloc).  This env variable sets the number of
 mallocs to fail.
 Here's why you care: If set to 0, then the malloc checking is skipped,
 which makes the test suite a heck of a lot faster. Just run with this
 env variable unset before you commit.

 Tests
 ===

 These are the test programs that are built if dbus is compiled using
 --enable-tests.

 dbus/dbus-test
 This is the main unit test program that tests all aspects of the D-Bus
 client library.

 dbus/bus-test
 This it the unit test program for the message bus.

 test/break-loader
 A test that tries to break the message loader by passing it randomly
 created invalid messages.

 test/name-test/*
 This is a suite of programs which are run with a temporary session bus.
 If your test involves multiple processes communicating, your best bet
 is to add a test in here.

 "make check" runs all the deterministic test programs (i.e. not break-loader).

 "make lcov-check" is available if you configure with --enable-compiler-coverage
 and gives a complete report on test suite coverage.

 Patches
 ===

 Please file them at http://bugzilla.freedesktop.org under component
 dbus, and also post to the mailing list for discussion.  The commit
 rules are:

  - for fixes that don't affect API or protocol, they can be committed
    if any one qualified reviewer other than patch author
    reviews and approves

  - for fixes that do affect API or protocol, two people
    in the reviewer group have to review and approve the commit, and
    posting to the list is definitely mandatory

  - if there's a live unresolved controversy about a change,
    don't commit it while the argument is still raging.

  - at their discretion, members of the reviewer group may also commit
    branches/patches under these conditions:

    - the branch does not add or change API, ABI or wire-protocol

    - the branch solves a known problem and is covered by the regression tests

    - there are no objections from the rest of the review group within
      a week of the patches being attached to Bugzilla

    - the committer gets a positive review on Bugzilla from someone they
      consider qualified to review the change (e.g. a colleague with D-Bus
      experience; not necessarily a member of the reviewer group)

  - regardless of reviews, to commit a patch:
     - make check must pass
     - the test suite must be extended to cover the new code
       as much as reasonably feasible (see Tests above)
     - the patch has to follow the portability, security, and
       style guidelines
     - the patch should as much as reasonable do one thing,
       not many unrelated changes
    No reviewer should approve a patch without these attributes, and
    failure on these points is grounds for reverting the patch.

 The reviewer group that can approve patches:

 Havoc Pennington <hp@pobox.net>
 Michael Meeks <michael.meeks@novell.com>
 Alexander Larsson  <alexl@redhat.com>
 Zack Rusin <zack@kde.org>
 Joe Shaw <joe@assbarn.com>
 Mikael Hallendal <micke@imendio.com>
 Richard Hult <richard@imendio.com>
 Owen Fraser-Green <owen@discobabe.net>
 Olivier Andrieu <oliv__a@users.sourceforge.net>
 Colin Walters <walters@verbum.org>
 Thiago Macieira <thiago@kde.org>
 John Palmieri <johnp@redhat.com>
 Scott James Remnant <scott@netsplit.com>
 Will Thompson <will.thompson@collabora.co.uk>
 Simon McVittie <simon.mcvittie@collabora.co.uk>
 David Zeuthen <davidz@redhat.com>
	The guidelines in this file are the ideals; it's better to send a
	not-fully-following-guidelines patch than no patch at all, though. We
	can always polish it up.

	Mailing list
	===

	The D-Bus mailing list is dbus@lists.freedesktop.org; discussion
	of patches, etc. should go there.

	Security
	===

	Most of D-Bus is security sensitive. Guidelines related to that:

	- avoid memcpy(), sprintf(), strlen(), snprintf, strlcat(),
	strstr(), strtok(), or any of this stuff. Use DBusString.
	If DBusString doesn't have the feature you need, add it
	to DBusString.

	There are some exceptions, for example
	if your strings are just used to index a hash table
	and you don't do any parsing/modification of them, perhaps
	DBusString is wasteful and wouldn't help much. But definitely
	if you're doing any parsing, reallocation, etc. use DBusString.

	- do not include system headers outside of dbus-memory.c,
	dbus-sysdeps.c, and other places where they are already
	included. This gives us one place to audit all external
	dependencies on features in libc, etc.

	- do not use libc features that are "complicated"
	and may contain security holes. For example, you probably shouldn't
	try to use regcomp() to compile an untrusted regular expression.
	Regular expressions are just too complicated, and there are many
	different libc's out there.

	- we need to design the message bus daemon (and any similar features)
	to use limited privileges, run in a chroot jail, and so on.

	http://vsftpd.beasts.org/ has other good security suggestions.

	Coding Style
	===

	- The C library uses GNU coding conventions, with GLib-like
	extensions (e.g. lining up function arguments). The
	Qt wrapper uses KDE coding conventions.

	- Write docs for all non-static functions and structs and so on. try
	"doxygen Doxyfile" prior to commit and be sure there are no
	warnings printed.

	- All external interfaces (network protocols, file formats, etc.)
	should have documented specifications sufficient to allow an
	alternative implementation to be written. Our implementation should
	be strict about specification compliance (should not for example
	heuristically parse a file and accept not-well-formed
	data). Avoiding heuristics is also important for security reasons;
	if it looks funny, ignore it (or exit, or disconnect).

	Development
	===

	D-Bus uses Git as its version control system. The main repository is
	hosted at git.freedesktop.org/dbus/dbus. To clone D-Bus, execute the
	following command:

	git clone git://git.freedesktop.org/dbus/dbus
	OR
	git clone git.freedesktop.org:dbus/dbus

	The latter form is the one that allows pushing, but it also requires
	an SSH account on the server. The former form allows anonymous
	checkouts.

	D-Bus development happens in two branches in parallel: the current
	stable branch, with an even minor number (like 1.0, 1.2 and 1.4), and
	the next development branch, with the next odd number.

	The stable branch is named after the version number itself (dbus-1.2,
	dbus-1.4), whereas the development branch is simply known as "master".

	When making a change to D-Bus, do the following:

	- check out the earliest branch of D-Bus that makes sense to have
	your change in. If it's a bugfix, it's normally the current stable
	branch; if it's a feature, it's normally the "master" branch. If
	you have an important security fix, you may want to apply to older
	branches too.

	- for large changes:
	if you're developing a new, large feature, it's recommended
	to create a new branch and do your development there. Publish
	your branch at a suitable place and ask others to help you
	develop and test it. Once your feature is considered finalised,
	you may merge it into the "master" branch.

	- for small changes:
	. make your change to the source code
	. execute tests to guarantee that you're not introducing a
	regression. For that, execute: make check
	(if possible, add a new test to check the fix you're
	introducing)
	. commit your change using "git commit"
	in the commit message, write a short sentence describing what
	you did in the first line. Then write a longer description in
	the next paragraph(s).
	. repeat the previous steps if necessary to have multiple commits

	- extract your patches and send to the D-Bus mailing list for
	review or post them to the D-Bus Bugzilla, attaching them to a bug
	report. To extract the patches, execute:
	git format-patch origin/master

	- once your code has been reviewed, you may push it to the Git
	server:
	git push origin my-branch:remote
	OR
	git push origin dbus-X.Y
	OR
	git push origin master
	(consult the Git manual to know which command applies)

	- (Optional) if you've not worked on "master", merge your changes to
	that branch. If you've worked on an earlier branch than the current
	stable, merge your changes upwards towards the stable branch, then
	from there into "master".

	. execute: git checkout master
	. ensure that you have the latest "master" from the server, update
	if you don't
	. execute: git merge dbus-X.Y
	. if you have any conflicts, resolve them, git add the conflicted
	files and then git commit
	. push the "master" branch to the server as well

	Executing this merge is recommended, but not necessary for all
	changes. You should do this step if your bugfix is critical for the
	development in "master", or if you suspect that conflicts will arise
	(you're usually the best person to resolve conflicts introduced by
	your own code), or if it has been too long since the last merge.


	Making a release
	===

	To make a release of D-Bus, do the following:

	- check out a fresh copy from Git

	- verify that the libtool versioning/library soname is
	changed if it needs to be, or not changed if not

	- update the file NEWS based on the git history

	- verify that the version number of dbus-specification.xml is
	changed if it needs to be; if changes have been made, update the
	release date in that file

	- update the AUTHORS file with "make update-authors" if necessary

	- the version number should have major.minor.micro, even
	if micro is 0, i.e. "1.0.0" and "1.2.0" not "1.0"/"1.2"; the micro
	version should be even for releases, and odd for intermediate snapshots

	- "make distcheck" (DO NOT just "make dist" - pass the check!)

	- if make distcheck fails, fix it.

	- once distcheck succeeds, "git commit -a". This is the version
	of the tree that corresponds exactly to the released tarball.

	- tag the tree with "git tag -s -m 'Released X.Y.Z' dbus-X.Y.Z"
	where X.Y.Z is the version of the release. If you can't sign
	then simply created an unsigned annotated tag:
	"git tag -a -m 'Released X.Y.Z' dbus-X.Y.Z".

	- bump the version number up in configure.ac (so the micro version is odd),
	and commit it. Make sure you do this after tagging the previous
	release! The idea is that git has a newer version number
	than anything released. Similarly, bump the version number of
	dbus-specification.xml and set the release date to "(not finalized)".

	- merge the branch you've released to the chronologically-later
	branch (usually "master"). You'll probably have to fix a merge
	conflict in configure.ac (the version number).

	- push your changes and the tag to the central repository with
	git push origin master dbus-X.Y dbus-X.Y.Z

	- scp your tarball to freedesktop.org server and copy it to
	dbus.freedesktop.org:/srv/dbus.freedesktop.org/www/releases/dbus/dbus-X.Y.Z.tar.gz.
	This should be possible if you're in group "dbus"

	- Update the online documentation with `make -C doc maintainer-upload-docs`.

	- update the wiki page http://www.freedesktop.org/Software/dbus by
	adding the new release under the Download heading. Then, cut the
	link and changelog for the previous that was there.

	- update the wiki page
	http://www.freedesktop.org/Software/DbusReleaseArchive pasting the
	previous release. Note that bullet points for each of the changelog
	items must be indented three more spaces to conform to the
	formatting of the other releases there.

	- post to dbus@lists.freedesktop.org announcing the release.


	Making a ".0" stable release
	===

	We create a branch for each stable release. The branch name should be
	dbus-X.Y which is a branch that has releases versioned X.Y.Z;
	changes on a stable branch should be limited to significant bug fixes.

	Because we won't make minor changes like keeping up with the latest
	deprecations on a stable branch, stable branches should turn off the
	gcc warning for deprecated declarations (e.g. see commit 4ebb275ab7).

	Be extra-careful not to merge master (or any branch based on master) into a
	stable branch.

	To branch:
	git branch dbus-X.Y
	and upload the branch tag to the server:
	git push origin dbus-X.Y

	To develop in this branch:
	git checkout dbus-X.Y

	Environment variables
	===

	These are the environment variables that are used by the D-Bus client library

	DBUS_VERBOSE=1
	Turns on printing verbose messages. This only works if D-Bus has been
	compiled with --enable-verbose-mode

	DBUS_MALLOC_FAIL_NTH=n
	Can be set to a number, causing every nth call to dbus_alloc or
	dbus_realloc to fail. This only works if D-Bus has been compiled with
	--enable-tests.

	DBUS_MALLOC_FAIL_GREATER_THAN=n
	Can be set to a number, causing every call to dbus_alloc or
	dbus_realloc to fail if the number of bytes to be allocated is greater
	than the specified number. This only works if D-Bus has been compiled with
	--enable-tests.

	DBUS_TEST_MALLOC_FAILURES=n
	Many of the D-Bus tests will run over and over, once for each malloc
	involved in the test. Each run will fail a different malloc, plus some
	number of mallocs following that malloc (because a fair number of bugs
	only happen if two or more mallocs fail in a row, e.g. error recovery
	that itself involves malloc). This env variable sets the number of
	mallocs to fail.
	Here's why you care: If set to 0, then the malloc checking is skipped,
	which makes the test suite a heck of a lot faster. Just run with this
	env variable unset before you commit.

	Tests
	===

	These are the test programs that are built if dbus is compiled using
	--enable-tests.

	dbus/dbus-test
	This is the main unit test program that tests all aspects of the D-Bus
	client library.

	dbus/bus-test
	This it the unit test program for the message bus.

	test/break-loader
	A test that tries to break the message loader by passing it randomly
	created invalid messages.

	test/name-test/*
	This is a suite of programs which are run with a temporary session bus.
	If your test involves multiple processes communicating, your best bet
	is to add a test in here.

	"make check" runs all the deterministic test programs (i.e. not break-loader).

	"make lcov-check" is available if you configure with --enable-compiler-coverage
	and gives a complete report on test suite coverage.

	Patches
	===

	Please file them at http://bugzilla.freedesktop.org under component
	dbus, and also post to the mailing list for discussion. The commit
	rules are:

	- for fixes that don't affect API or protocol, they can be committed
	if any one qualified reviewer other than patch author
	reviews and approves

	- for fixes that do affect API or protocol, two people
	in the reviewer group have to review and approve the commit, and
	posting to the list is definitely mandatory

	- if there's a live unresolved controversy about a change,
	don't commit it while the argument is still raging.

	- at their discretion, members of the reviewer group may also commit
	branches/patches under these conditions:

	- the branch does not add or change API, ABI or wire-protocol

	- the branch solves a known problem and is covered by the regression tests

	- there are no objections from the rest of the review group within
	a week of the patches being attached to Bugzilla

	- the committer gets a positive review on Bugzilla from someone they
	consider qualified to review the change (e.g. a colleague with D-Bus
	experience; not necessarily a member of the reviewer group)

	- regardless of reviews, to commit a patch:
	- make check must pass
	- the test suite must be extended to cover the new code
	as much as reasonably feasible (see Tests above)
	- the patch has to follow the portability, security, and
	style guidelines
	- the patch should as much as reasonable do one thing,
	not many unrelated changes
	No reviewer should approve a patch without these attributes, and
	failure on these points is grounds for reverting the patch.

	The reviewer group that can approve patches:

	Havoc Pennington <hp@pobox.net>
	Michael Meeks <michael.meeks@novell.com>
	Alexander Larsson <alexl@redhat.com>
	Zack Rusin <zack@kde.org>
	Joe Shaw <joe@assbarn.com>
	Mikael Hallendal <micke@imendio.com>
	Richard Hult <richard@imendio.com>
	Owen Fraser-Green <owen@discobabe.net>
	Olivier Andrieu <oliv__a@users.sourceforge.net>
	Colin Walters <walters@verbum.org>
	Thiago Macieira <thiago@kde.org>
	John Palmieri <johnp@redhat.com>
	Scott James Remnant <scott@netsplit.com>
	Will Thompson <will.thompson@collabora.co.uk>
	Simon McVittie <simon.mcvittie@collabora.co.uk>
	David Zeuthen <davidz@redhat.com>