Question about file desriptors.
thiago at kde.org
Tue Sep 22 08:43:32 PDT 2009
Em Terça-feira 22 Setembro 2009, às 15:46:48, Stef Bon escreveu:
> > This is done completely independently of the system daemon.
> Ok, two questions: what's a X11 atom?
You don't need to care about that, unless you want to read the dbus-launch-
x11.c source code.
Suffice to say that dbus-launch stores the bus address and PID in the X11
server, under a well-defined name that is also keyed to your machine and to
your user name. That creates a perfect 1:1 tying of a session bus with the
machine, username and X11 display.
> And what's so special about it that the dbus-launch program wants info
> from it?
That's where the bus address is saved in the X11 server.
I can explain the technical details, but I fear they would go completely over
your head (if you're asking what an atom is, you probably have no experience
with the X11 low-level library), and would also be completely irrelevant to
> >> Is it really neccesary that the dbus-daemon for a session is started by
> >> dbus-launch?
> > No, you could run it manually, then set the environment variables on your
> > own.
> >> I've read that
> >> the filedescriptors are used by programs that launch the message bus.
> >> Is this mandatory??
> > Sorry, I did not understand the question.
> OK, the question is not clear when I reread it. Is it a must to use
Yes. The bus daemon prints the information in separate file descriptors, so
that the dbus-launch program can more easily read them.
> As I understand, the files (to store pid and the address) are created
> and opened
> by dbus-launch, and the dbus-daemon --session program writes to these
> files via
> the filedescriptor. It's also possible to let the dbus-daemon session
> let create the files,
> and the dbus-launch read it after it has started it?
I don't know if it can create the files.
That's simply a communication mechanism between dbus-daemon and dbus-launch.
You shouldn't need to care about them in your application. And you shouldn't
be using them to launch D-Bus. You should be using dbus-launch.
> Ok, to be clear, I'm looking for other ways to start the session dbus,
> like ConsoleKit and/or Upstart.
> ConsoleKit is the tool for sessionmanagment, and Upstart the tool to
> start programs/scripts
> (in order acoording to dependency). I think that these should somehow
> How do you look at this?
No need for any change. The official way to start a session bus is via dbus-
launch. That should be enough.
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
Senior Product Manager - Nokia, Qt Development Frameworks
PGP/GPG: 0x6EF45358; fingerprint:
E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358
Qt Developer Days 2009 | Registration Now Open!
Munich, Germany: Oct 12 - 14 San Francisco, California: Nov 2 - 4
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Size: 189 bytes
Desc: This is a digitally signed message part.
Url : http://lists.freedesktop.org/archives/dbus/attachments/20090922/9a15630d/attachment.pgp
More information about the dbus