On 07/19/2016 07:30 AM, fsmithred wrote:
> 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
>
>

One more test - instead of 'chmod -R 000 /lib/systemd' I tried 'chmod -x
/lib/systemd/systemd-udevd' thus disabling an executable binary file that
libsystemd0 provides. Dropped to runlevel 1, ctrl-d to return to desktop,
and removable drives no longer appear on the desktop.

-fsr