Bug 69877

Summary:	dbus-launch will refuse start a dbus-daemon though the previous started was terminated
Product:	dbus	Reporter:	Chengwei Yang <chengwei.yang.cn>
Component:	core	Assignee:	D-Bus Maintainers <dbus>
Status:	RESOLVED MOVED	QA Contact:	D-Bus Maintainers <dbus>
Severity:	normal
Priority:	medium	CC:	chengwei.yang.cn, msniko14, thiago
Version:	1.5
Hardware:	All
OS:	All
Whiteboard:
i915 platform:		i915 features:

Description Chengwei Yang 2013-09-27 10:27:56 UTC

dbus-launch which used to start a dbus-daemon mainly used in autolaunch:, in this situation, dbus-launch will save related infomations into X window system, for example, the bus daemon address. And will decide whether a dbus-daemon is already running according to if an address can get from X window system.

So here comes the problem: if the previously started dbus-daemon was terminated but the dbus-launch is still running, then the next connection request will always fail because dbus-launch refused to start a dbus-daemon.

This behaviour somehow like #bug25841, I'm not quite sure.

Comment 1 Simon McVittie 2013-09-27 11:30:28 UTC

I think the solution is probably to have dbus-launch connect to its own dbus-daemon (without turning off exit-on-disconnect), so that it will automatically exit if the dbus-daemon goes away.

That would require dbus-launch to link to either libdbus-1 (shared library) or libdbus-internal (murky static library), preferably the former, but I think that'd be fine.

Comment 2 Simon McVittie 2013-09-27 11:34:42 UTC

If people like dbus-launch, review/testing of the new --exit-with-x11 option on Bug #39197 would also be useful. It addresses the dbus-launch misfeature that "--exit-with-session" tries to work in a non-X11 environment, and tries to poll a terminal on its stdin to detect the end of a tty session (even though it's not clear whether that actually works).

One day, I would like dbus-launch to be an X11-specific historical curiosity that nobody actually uses any more - it shouldn't be used in Wayland, for instance.

Comment 3 Chengwei Yang 2013-11-20 13:08:14 UTC

(In reply to comment #1)
> I think the solution is probably to have dbus-launch connect to its own
> dbus-daemon (without turning off exit-on-disconnect), so that it will
> automatically exit if the dbus-daemon goes away.

Just investigated this solution, seems it doesn't work. exit-on-disconnect means the program will call _exit() after handled disconnected signal.

However, if dbus-daemon was killed, it didn't send disconnected signal before exit.

> 
> That would require dbus-launch to link to either libdbus-1 (shared library)
> or libdbus-internal (murky static library), preferably the former, but I
> think that'd be fine.

Comment 4 Simon McVittie 2013-11-20 13:25:33 UTC

(In reply to comment #3)
> However, if dbus-daemon was killed, it didn't send disconnected signal
> before exit.

Really? I thought the Disconnected signal was synthesized client-side by libdbus when the kernel notifies it that the socket has been closed?

After all, clients that send invalid UTF-8 normally get an unceremonious close() from the dbus-daemon, and then _exit() when that happens (indeed, plenty of people, including me, have complained about that behaviour).

Comment 5 Chengwei Yang 2013-12-10 13:47:40 UTC

*** Bug 8294 has been marked as a duplicate of this bug. ***

Comment 6 GitLab Migration User 2018-10-12 21:16:59 UTC

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

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