J5’s Blog

We’ll I’m going to dive into the deep end (flames welcome) because I have been talking to people about the Qt “possibility” since Nokia bought Trolltech and GNOME was considering what to do for the future of its toolkit.  I can see the headlines of yet another GNOME developer advocating using Qt4 as the basis of future releases but this simply is not the case.  It is, in its basic form, an exercise in “what ifs?” and an iterative process of looking inward at our ecosystem and seeing the pros and cons of certain directions we could take.

Is this going to happen?

First off this is a highly unlikely scenario. The planets would have to align, Qt would have to go LGPL, Nokia would have to loosen controls on contributions to avoid a fork, the Qt team would have to accept a community which has slightly different goals and the GTK+ team would have to signal their willingness to move. We are not going to turn our back on the great work the GTK+ teams are doing and most certainly the base libraries we use such as GStreamer wouldn’t change.

What are the possible advantages?

• Less confusion for the non-insiders on what to learn and program for
• We can get rid of the whole Freedesktop common widgets talk (e.g. Print and File dialogs) which is nonsense and a distraction anyway
• Hopefully less bickering in the community meaning a more unified and focused front against larger threats
• Focus can move from the lower toolkit layers to the higher level desktop layer which really define the value differences between GNOME and KDE
• Easier technology sharing

Note that these are all only possible advantages and may not even happen even if there was a move.

 What are the possible disadvantages?

• More bickering on how to write applications (who’s approach to usability wins out?)
• Less focus and a return to writing applications without a shared guideline (just look at old XLib interfaces - almost like snowflakes)
• A loss of identity
• Loss of amazing GTK+ developers who may feel abandoned
• Splintering of the community so we have parallel GTK+ GNOME and Qt4 GNOME development
• Screwing ISV’s who bank on GTK+’s stable interface
• GTK+ isn’t just a license - we would be losing a lot by switching away from the codebase
• Falling into the growing pains GTK+ 2.0 brought GNOME and Qt4 is still bringing KDE
• A loss of activity at Freedesktop.org which is actually sometimes useful in producing dialogue and shared practices
• A loss of control over the direction of the toolkit effecting the quality and feel of the GNOME desktop
• Really a lot of development is moving to the web - will toolkits be important enough to warrant the pain of the move

What this wouldn’t be

This wouldn’t be a merging of GNOME and KDE.  Each community has a different idea of what constitutes a usable desktop and Qt would simply be an implementation detail bellow GNOME.

Conclusion

This is pretty much a pipe dream.  It solves some issues while creating a whole host of different ones.  I’m not going to advocate it other than seeing what peoples reactions are.  On the flip side if the work was put behind it, the planets aligned, and both communities came to an agreement I wouldn’t object to the arrangement.  Needless to say, I’m not holding my breath nor would I be elated or saddened if it did or did not happen. To me it is all what is best for Linux, GNOME, Free Software and the wider market. It is unclear what direction would be best (any claims to that knowledge would be suspect) but honestly and actively looking at the possibilities is a useful activity, however remote. People reading should not put their “hopes and dreams” on this or believe it to be more than it is.

That’s right, in order to support the upcomming release of GNOME 3.0 which is introducing a new tabbed interface, we’ve totally made D-Bus HIG compliant by adding tabs to the API.  No longer do you have to select a system or session bus while connecting.  Now all you have to do is select the correct tab and you are connected.  Now you might be saying, I can’t see these tabs.  Because of constraints of the D-Bus system, namely not having a GUI, we had to add virtual tabs.  Don’t worry, they are there, you just have to randomly click and eventually you will select the right bus.  Or you can simply use the new D-Bus Gtk+ bindings which exist to provide a GUI in which to display the tabs.  A word of warning though, because of Qt4’s abstraction layers when using the D-Bus Qt4 library they will show up as plasmoids.  We here at Freedesktop.org hopes this makes your D-Bus hacking a much more enjoyable experience.

Due to issues putting the re-licensing effort on hold indefinitely, it has been decided to move to 1.2.x versioning scheme. Being that 1.1.20 is considered to also be 1.2.0 and this being the second release in the 1.2.x stable series we have versioned this release 1.2.1. This release contains a number of bug fixes identified after 1.1.20:

• compiles under some older versions of glibc
• compiles without X support once again
• fix stuck server grab if dbus-launch is run in an existing D-Bus X session
• various Mac OSX build fixes added
• don’t use the broken poll call on Mac OSX
• better checks for linker flag support should allow D-Bus to link under various linkers
• exit_on_disconnect is set after the connection registers with a bus so we don’t exit if we get a disconnect during the handshake
• dicts now work correctly with dbus-send
• inotify backend is now less aggressive
• pending calls expire correctly
• memleak of uuid when the bus is autolaunched fixed

D-Bus is a message bus system, a simple way for applications to talk to one another. In addition to interprocess communication, D-Bus helps coordinate process lifecycle; it makes it simple and reliable to code a “single instance” application or daemon, and to launch applications and daemons on demand when their services are needed.

Get it now at:

http://dbus.freedesktop.org/releases/dbus/dbus-1.2.1.tar.gz

All stable development will now happen on the “dbus-1.2-branch” branch and all unstable development should happen on the “master” branch.

I got back from the BOSSA conference last week. It still is my favorite conference for just talking to people and getting things rolling. The organizers keep it small and limit the number of talks so that people can get to what they do best and just talk to each other. While I am no longer directly involved in embedded development I still feel this should be the target of most developers. A win on current generation embedded devices means improvements across the board from those devices to the desktop and even the server room. Most of my debugging and optimization techniques for D-Bus, the focus of my BOSSA talk, were gained from working with it on embedded devices. I continue to gear my work with the idea that in the near future a large portion of the people consuming those technologies will be doing so on devices that are considered to be “embedded”.

I’m currently in the miami airport having a Boston Lager to celebrate St. Patrick’s day while waiting for my flight to San Paulo, Brazil. BOSSA will be a blast but I do regret not being able to celebrate with my friends back in Boston.

A little over a year after releasing D-Bus 1.0.0 I am proud to announce the beginning of a new series of stable releases. This is effectively the 1.2.x stable series though the version does not reflect that yet due to non-technical reasons discussed in the release notes bellow. This replaces the 1.0.x series while still staying ABI compatible. What this means is that applications written for the 1.0.x versions of D-Bus should still run unmodified using the 1.2.x library and bus.

D-Bus is a message bus system, a simple way for applications to talk to one another. In addition to interprocess communication, D-Bus helps coordinate process lifecycle; it makes it simple and reliable to code a “single instance” application or daemon, and to launch applications and daemons on demand when their services are needed.

Major Version Feature List

• Features
  • The system bus now supports starting services on demand. This uses a setuid helper program because system bus daemon runs as a nobody user, while services it launches may need to run as a different user.
    • A design doc is available in doc/system-activation.txt
  • The TCP address format has been enhanced, such that TCP may be actually usable.
    • The dbus-daemon man page describes the new elements in the address format.
  • Support ANONYMOUS mechanism for authentication, which allows a client to authenticate as nobody in particular
    • The ANONYMOUS support means you can now use D-Bus (without a bus daemon) as a protocol for a network service provided to anonymous Internet or LAN clients.
  • Autolaunched busses now save their parameters in X11 if possible making them behave closer to busses launched through the normal mechanisms
  • inotify is now the default backend for watching configuration file changes
  • Better thread support.
  • The bus daemon now generates a globally-unique ID for itself.
    • Use this as a unique ID for a user’s session, for example.
  • Support for message serialization added for use with external transports like TUBES!!!
  • Better eavesdropping support now picks up reply messages for debugging
• Library API additions
  • dbus_connection_set_allow_anonymous() - allow the message stream to begin if the client auths as anonymous (otherwise, the client will be dropped unless they auth as a user).
  • dbus_watch_get_unix_fd() - replaces dbus_watch_get_fd
  • dbus_watch_get_socket() - replaces dbus_watch_get_fd
  • dbus_server_get_id() - available to access the unique ID of a particular address
  • dbus_connection_get_server_id() - available to access the unique ID of a particular address
  • dbus_message_marshal() - serializes a message into a byte array
  • dbus_message_demarshal() - de-serializes a byte array into a message
• Library API deprecations
  • dbus_watch_get_fd() - had unclear cross-platform semantics
• Protocol additions
  • Argument path matching of the type arg0path=’/aa/bb/’ is now supported
  • New error org.freedesktop.DBus.Error.ObjectPathInUse added
  • ANONYMOUS auth support added
  • GetAll call added to the properties interface for getting a list of properties an object exports

Release Notes

• This is the next generation supported STABLE release of D-Bus. For all intents and purposes this is the 1.2.0 release WITHOUT the planned X11/MIT license change due to a couple of license holders who have yet to respond. For the most part this license change is being pursued to simplify licensing issues and fix a couple of licensing corner cases. When this happens D-Bus will be released under the 1.2.0 version.
• D-Bus 1.0.x effectively goes into security fix mode and will only be updated for major issues.
• Fixed CVE-2008-0595 - security policy of the type <allow send_interface= “some.interface.WithMethods“/> work as an implicit allow for messages sent without an interface bypassing the default deny rules and potentially allowing restricted methods exported on the bus to be executed by unauthorized users.
• Fixes dbus-launch so the session bus goes away so does D-Bus
• Builds against latest gcc/glibc changes
• Correctly unref connections without guids during shutdown
• About the name: Submitted by Greg K Nicholson, Coniston Water is a lake in Cumbria, England where several water speed records have been broken. Between 1956 and 1959 Sir Malcolm’s son Donald Campbell set four successive records on the lake in Bluebird K7, a hydroplane. Wikipedia

Get D-Bus 1.1.20 “Coniston Water”!!!

Go to the D-Bus web site for more information.

Well folks, D-Bus 1.1.3 has a little bug introduced via the inotify patch which would consume 100% of your memory, go into the OOM killer and subsequently consume 100% of your CPU. This is exactly why we have the Release Candidate series, to root out any last minute issues. Thanks to all who tested and sacrificed their productivity to get us to this next release. D-Bus 1.1.4 (1.2.0RC2) is now available for your perusal.

Download: http://dbus.freedesktop.org/releases/dbus/dbus-1.1.4.tar.gz
Homepage: http://www.freedesktop.org/wiki/Software/dbus

Who knew if you promise something you have to deliver. Well here you are, D-Bus 1.1.3 or as I like to refer to it 1.2.0RC1. That’s right, if everything goes well within a week we should have our second major D-Bus release. I’ll wait until then to get nostalgic about the great old days of 1.0.0 “Blue Bird”. Why when I was your age D-Bus wasn’t even at a major version and we didn’t even have a recursive type system…but I digress. Here is the info you have been waiting for:

• This release is intended to be Release Candidate 1 of major release D-Bus 1.2.0. If nothing is found to be wrong with this release it will become 1.2.0 within a week. If we need to make major changes we will release an RC2 and start the process over
  again. 
• This is a development release, so API’s may still change if problems are found (though this is extremely unlikely). 
• DTD for the introspection format is fixed and uploaded to the servers 
• Sources now reside in a git repository at http://gitweb.freedesktop.org/?p=dbus/dbus.git;a=summary 
• Argument path matching of the type arg0path=’/aa/bb/’ is now supported (see the specification for more information) 
• New error org.freedesktop.DBus.Error.ObjectPathInUse added 
• Autolaunched busses now save their parameters in X11 if possible making them behave closer to busses launched through the normal mechanisms 
• inotify is now the default backend for watching configuration file changes 
• More support for the AIX platform has been added 
• Numerous bug fixes and performance enhancements

Download: http://dbus.freedesktop.org/releases/dbus/dbus-1.1.3.tar.gz
Homepage: http://www.freedesktop.org/wiki/Software/dbus

P.S. Anyone want to suggest a name for 1.2.0? The rules are it needs to have some logical connection to the previous major release “Blue Bird”.

Just thought I would take “release early, release often” to heart. Hot on the heels of 0.1.7 is a major feature release 0.1.8. As of this version all complex and simple D-Bus types are displayed properly in the UI even if they are nested.

Please let me know if you ever see an Error(<some char>) in the parameter lists.

As usual:

Homepage: http://d-feet.fedorahosted.org

Tarball: http://johnp.fedorapeople.org/d-feet-0.1.8.tar.gz

Rawhide and Fedora 8: yum install d-feet

• update the license for _introspect_parser.py to permissive since dbus-python was relicensed (this just makes including this code easier since the GPL/AFL dual license confused some people)
• add placeholder icons to denote methods, properties and signals, does someone want to make a standard set of programmer tool icons?
• default service icon now added to the package for distributions that do not ship an icon called icon-service
• argument types now show the parameter name if given in the introspect data
• selecting a property now attempts to read the property and display a value
• prettier formatting for introspect output
• various bug fixes

Tarball:

http://johnp.fedorapeople.org/d-feet-0.1.7.tar.gz

Rawhide and Fedora 8:

yum install d-feet