Shairport-sync: Problem with D-Bus interface [Resolved]

[thk4711]

Hi,

today I built shairport-sync with D-Bus inerface enabled. When I start shairport I get the following error:

Could not acquire a Shairport Sync native D-Bus interface "org.gnome.ShairportSync.i790" on the system bus.

On a different system with an older version of shairport-sync it is working.

Thomas

[mikebrady]

Hi Thomas. I presume you followed the normal sequence ending with make and sudo make install. Apart from installing Shairport Sync, a set of permissions is installed to allow Shairport Sync to provide the D-Bus service on the system bus, but only if it is running under the user and group shairport-sync. It doesn't need any permission to start a service on the session bus of the logged-in user, but many Linuxes (e.g. Raspbian Lite) do not provide a session bus.

[thk4711]

Hi,

thank you for your hint. After I did the following:

# cp /usr/local/etc/dbus-1/system.d/shairport-sync-dbus.conf /etc/dbus-1/system.d/

it is working now.

Regards
Thomas

[mikebrady]

Thanks. What OS are you running on, please?

[thk4711]

I am running the latest version of Raspbian.

$ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)"
NAME="Raspbian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"

[mikebrady]

Many thanks. I must look into that oddness.

[mikebrady]

Is is possible that you did not set the sysconfdir to /etc in the ./configure step?

[thk4711]

I checked my history and you are right I did not set the sysconfigdir. Because of that I also had to create the /usr/local/etc/dbus-1/system.d/ dir in order to run make install without errors.

[mikebrady]

That's great thanks -- mystery solved.

[icpenguins]

@mikebrady I didn't do the build locally; I pulled down the package on my Ubuntu raspberry pi install. I am receiving this message. Any thoughts on where to go from here? I don't have any content under the /usr/local/etc/... folder.

shairport-sync.service - ShairportSync AirTunes receiver
     Loaded: loaded (/lib/systemd/system/shairport-sync.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2020-10-21 20:33:07 UTC; 5min ago
       Docs: man:shairport-sync(7)
             file:///usr/share/doc/shairport-sync/README.md.gz
             https://github.com/mikebrady/shairport-sync
   Main PID: 5005 (shairport-sync)
      Tasks: 16 (limit: 4436)
     CGroup: /system.slice/shairport-sync.service
             └─5005 /usr/bin/shairport-sync

Oct 21 20:33:07 audio-server systemd[1]: Started ShairportSync AirTunes receiver.
Oct 21 20:33:07 audio-server shairport-sync[5005]: Could not acquire a Shairport Sync native D-Bus interface "org.gnome.ShairportSync.i5005" on the system >
Oct 21 20:33:07 audio-server shairport-sync[5005]: Could not acquire an MPRIS interface named "org.mpris.MediaPlayer2.ShairportSync.i5005" on the system bu

[mikebrady]

Thanks for the post. Can I ask if you tried restarting the device? The D-Bus system needs to read the security policy for Shairport Sync before it is allowed to provide the service and the only way I know to force it is to restart.

[icpenguins]

@mikebrady I just did a restart and get the same message. It doesn't, outwardly, appear to affect operations. Is this something that is impacting functionality?

[mikebradytcd]

Thanks for the update. It does not affect functionality at all, unless you wish to use some of the remote control facilities, so I wouldn't worry about it. It might be worth checking back through some of the closed issues -- it rings a faint bell -- but it is harmless.

[mikebradytcd]

Just by the way, does the file /etc/dbus-1/system.d/shairport-sync-dbus.conf exist? And if so, could you post its contents here, please?

[mikebradytcd]

...and maybe the output from $ ps aux | grep shair, please?

[icpenguins]

That file does not exist. Here is the output from the above request.

shairpo+    1762  0.6  0.2 638772 11128 ?        Ssl  07:59   0:18 /usr/bin/shairport-sync
<redact>       4936  0.0  0.0   7684   648 pts/0    S+   08:46   0:00 grep --color=auto shair

[mikebradytcd]

Thanks. If you felt like it, you could try creating the file /etc/dbus-1/system.d/shairport-sync-dbus.conf with the following contents in it -- it's the security policy, and it should have been installed:

<!-- initial version, based on /etc/dbus-1/system.d/avahi-dbus.conf, with thanks -->
<!DOCTYPE busconfig PUBLIC
          "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
          "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <!-- Allow users "root" and "shairport-sync" to own the Shairport Sync service -->
  <policy user="root">
    <allow own="org.gnome.ShairportSync"/>
  </policy>
  <policy user="shairport-sync">
    <allow own="org.gnome.ShairportSync"/>
  </policy>


  <!-- Allow anyone to invoke methods on Shairport Sync server -->
  <policy context="default">
    <allow send_destination="org.gnome.ShairportSync"/>
    <allow receive_sender="org.gnome.ShairportSync"/>
  </policy>

</busconfig>

You'll have to have supervisor privileges, and its permissions and ownership should look like this:

-rw-r--r-- 1 root root 747 Sep 30 14:55 shairport-sync-dbus.conf

As I mentioned previously, the fault is harmless, but this might just make it work properly.

[icpenguins]

That fixed one of the two issues! 👍 Thank you! Here is the output from systemctl.

● shairport-sync.service - ShairportSync AirTunes receiver
     Loaded: loaded (/lib/systemd/system/shairport-sync.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2020-10-22 09:05:01 PDT; 5s ago
       Docs: man:shairport-sync(7)
             file:///usr/share/doc/shairport-sync/README.md.gz
             https://github.com/mikebrady/shairport-sync
   Main PID: 6033 (shairport-sync)
      Tasks: 10 (limit: 4436)
     CGroup: /system.slice/shairport-sync.service
             └─6033 /usr/bin/shairport-sync

Oct 22 09:05:01 audio-server systemd[1]: Started ShairportSync AirTunes receiver.
Oct 22 09:05:01 audio-server shairport-sync[6033]: Could not acquire an MPRIS interface named "org.mpris.MediaPlayer2.ShairportSync.i6033" on the system bu

[mikebradytcd]

Excellent. The other problem is very similar -- the MPRIS service policy document is missing for some reason.
If you create another, similar, file at /etc/dbus-1/system.d/shairport-sync-mpris.conf with the following contents:

<!-- initial version, based on /etc/dbus-1/system.d/avahi-dbus.conf, with thanks -->
<!DOCTYPE busconfig PUBLIC
          "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
          "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <!-- Allow users "root" and "shairport-sync" to own the Shairport Sync MPRIS service -->
  <policy user="shairport-sync">
    <allow own="org.mpris.MediaPlayer2.ShairportSync"/>
  </policy>
  <policy user="root">
    <allow own="org.mpris.MediaPlayer2.ShairportSync"/>
  </policy>

  <!-- Allow anyone to invoke methods on Shairport Sync MPRIS server -->
  <policy context="default">
     <allow send_destination="org.mpris.MediaPlayer2.ShairportSync"/>
    <allow receive_sender="org.mpris.MediaPlayer2.ShairportSync"/>
  </policy>

</busconfig>

With luck, that will resolve the second issue.

[icpenguins]

Done! :) All working! Thanks for the quick response and resolve 💯