On 07/18/2016 04:36 PM, Rick Moen wrote:
> Quoting Hendrik Boom (hendrik@???):
>> On Mon, Jul 18, 2016 at 08:54:44AM -0400, fsmithred wrote:
>
>>> Pretty cool trick. I tried it and got mixed results. I'm running without
>>> libsystemd0 here, so I can't have gvfs-daemons. That means there's no
>>> trash icon on the desktop and removable drives don't show up on the
>>> desktop when they're plugged it.
>>>
>>> With a dummy equivs libsystemd0, I get a trash icon that works, but the
>>> removable drives don't show up on the desktop. When I remove the dummy
>>> package and install the real libsystemd0, removables show up and
>>> mount/eject work as expected.
>>
>> So it does look as if libsystemd0 does do something.
>
> That doesn't logically follow. My guesstimate is that some GNOME
> plumbing is checking for some library function before it offers
> the user 'removable drives [...] on the desktop'. For libsystemd0
> library functions to _do_ anything reportedly requires systemd be
> present to be reached below the library, i.e., the lib is just interface
> glue.
>
> If you really want to know for certain, read the calling and answering
> source code. (I won't bother, because I really have no interest at all
> in GNOME, and prefer to avoid it.)
>
> GNOME is a brittle dependency hairball. Surely that fact is clear, if
> nothing else is.
>

Rick, I don't understand your reasoning here. What I see is that gvfs can
do something when the real libsystemd0 is installed that it can't do
without libsystemd0 - that is, it shows removable drives on the desktop.
The presence of systemd itself is not required for this - it's not installed.

Gnome probably has nothing at all to do with this. The only gnome packages
installed here are gnome-accessibility-themes, gnome-icons,
libgnome-keyring and libsoup-gnome. I'm running xfce desktop.

The next experiment I did was to chmod -R 000 /lib/systemd/. I'm running
this on a live-usb, so I can't reboot without losing changes. I tried
restarting udev and dbus one at a time, and additional usb drives still
show up on the desktop. Tried logging out of the desktop and back in, and
the drives still show up. Then I dropped to runlevel 1 and then went back
to 2 and got to the desktop. The removalble drives stopped showing up on
the desktop. I don't know what had to restart to make the permission
changes take effect.

One odd thing: Fixed drives that are not in fstab show up on the desktop.
This was not affected by the change in permissions on /lib/systemd, but it
did depend on the presence of the real libsystemd0. Those drives don't
show up on the desktop with the dummy libsystemd0 package.

I tried reading the source code for libsystemd0, but I don't read C, so I
got nothing out of it.

-fsr