lightdm: low dependency login/display manger #875

thomas · 2018-08-22T11:06:27Z

Home page:

Build and base setup is taken from:

http://linuxfromscratch.org/blfs/view/svn/x/lightdm.html

Notes:

lightdm must be installed to build greeters
gdm now means GraphicalDisplayManger

Final installation:

install a greeter (slick-greeter)

Tell the system to use lightdm instead of
gdm after the next reboot

#> systemctl disable gdm
#> systemctl enable lightdm

Test w/o reboot

#> systemctl disable gdm --now
#> systemctl enable lightdm --now

Play with the config under /etc/lightdm or not

Mind the usual commands

#> systemctl restart lightdm
#> systemctl daemon-reload
#> systemctl restart systemd-logind

Home page: https://github.com/CanonicalLtd/lightdm Build and base setup is taken from: http://linuxfromscratch.org/blfs/view/svn/x/lightdm.html Notes: - lightdm must be installed to build greeters - gdm now means GraphicalDisplayManger - Final installation: install a greeter (slick-greeter) Tell the system to use lightdm instead of gdm after the next reboot #> systemctl disable gdm #> systemctl enable lightdm - Test w/o reboot #> systemctl disable gdm --now #> systemctl enable lightdm --now Play with the config under /etc/lightdm or not Mind the usual commands #> systemctl restart lightdm #> systemctl daemon-reload #> systemctl restart systemd-logind

pmenzel

I’d put the commit from merge/pull request #876 in here too.

pmenzel · 2018-08-22T11:15:30Z

lightdm.be0

+    --sbindir=/usr/bin                              \
+    --sysconfdir=/etc                               \
+    --docdir=/usr/share/doc/lightdm-${PKGVERSION}   \
+    --disable-static                                \


I’d prefer not specifying the default, to make the resulting configure line shorter.

lightdm-1.26.0-0/source/configure --prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --libexecdir=/usr/libexec --sysconfdir=/etc --sharedstatedir=/var --localstatedir=/var --libdir=/usr/lib --includedir=/usr/include --datarootdir=/usr/share --datadir=/usr/share --infodir=/usr/share/info --localedir=/usr/share/locale --mandir=/usr/share/man --docdir=/usr/share/doc/lightdm --exec-prefix=/usr --prefix=/usr --libexecdir=/usr/lib/lightdm --localstatedir=/var --sbindir=/usr/bin --sysconfdir=/etc --docdir=/usr/share/doc/lightdm-1.26.0 --disable-static --disable-tests --enable-liblightdm-qt=no --with-greeter-user=gdm --with-greeter-session=slick-greeter

pmenzel · 2018-08-22T11:17:41Z

lightdm.be0

+  install -v -dm755 -o gdm -g gdm ${D}/var/lib/lightdm
+  install -v -dm755 -o gdm -g gdm ${D}/var/lib/lightdm-data
+  install -v -dm755 -o gdm -g gdm ${D}/var/cache/lightdm
+  install -v -dm770 -o gdm -g gdm ${D}/var/log/lightdm


This break building this bee file as a normal user.

[BEE] => entering mee_install_post() .. install: creating directory ‘/dev/shm/bee-pmenzel/lightdm/lightdm-1.26.0-0/image/var’ install: creating directory ‘/dev/shm/bee-pmenzel/lightdm/lightdm-1.26.0-0/image/var/lib’ install: creating directory ‘/dev/shm/bee-pmenzel/lightdm/lightdm-1.26.0-0/image/var/lib/lightdm’ install: cannot change owner and permissions of ‘/dev/shm/bee-pmenzel/lightdm/lightdm-1.26.0-0/image/var/lib/lightdm’: Operation not permitted

pmenzel · 2018-08-22T11:18:06Z

lightdm.be0

+mee_install_post() {
+
+  sed '/bin\/sh/ a \\n. /etc/profile' ${S}/tests/src/lightdm-session > ${D}/usr/bin/lightdm-session
+  chmod 755 ${D}/usr/bin/lightdm-session


What are the default permissions?

$ ls -l /dev/shm/bee-pmenzel/lightdm/lightdm-1.26.0-0/image/usr/bin/ total 1400 -rwxr-xr-x 1 pmenzel pmenzel 54128 Aug 22 13:19 dm-tool -rwxr-xr-x 1 pmenzel pmenzel 1370176 Aug 22 13:19 lightdm -rw-r--r-- 1 pmenzel pmenzel 201 Aug 22 13:19 lightdm-session

Upstream bug https://github.com/CanonicalLtd/lightdm/issues/37 reported.

pmenzel · 2018-08-22T11:19:35Z

lightdm.be0

+
+	[Service]
+	ExecStart=/usr/bin/lightdm
+	StandardOutput=syslog


You probably copied that from the GDM service unit, but I think it’s not needed.

pmenzel · 2018-08-22T11:52:44Z

I tested this on keineahnung, and logging into my Xfce session, the Xfce panel is not scaled anymore (Settings → Appearance → Settings → Window scaling 2x).

thomas · 2018-08-22T12:42:37Z

I can confirm this for thehawk, have you checked this with the xfce4_hidpi session or the default one?
From the logs I can't tell what's happening (also its not really possible to test this on a small monitor).
Can the panel height be set manually?

pmenzel · 2018-08-22T12:50:46Z

On 08/22/18 14:42, Thomas Kreitler wrote: I can confirm this for thehawk, have you checked this with the xfce4_hidpi session or the default one?

I used the default one. xfce4_hidpi is not needed anymore.

From the logs I can't tell what's happening (also its not really possible to test this on a small monitor). Can the panel height be set manually?

Yes, but it’s not feasible, as we can log into systems with different monitors.

thomas · 2018-08-22T13:25:07Z

I used the default one. xfce4_hidpi is not needed anymore.

Then, what are the differences between xfce4_hidpi and xfce?

Could it be, that this is an issue with xfce 4.13, which is a developer release?

pmenzel · 2018-08-22T13:38:48Z

On 08/22/18 15:25, Thomas Kreitler wrote: > I used the default one. xfce4_hidpi is not needed anymore. Then, what are the differences between xfce4_hidpi and xfce?

The session xfce4_hidpi is a relict (outside of bee packages) from Xfce 4.12. ``` $ sudo bee query /usr/share/xsessions/xfce4_hidpi.desktop $ more /usr/share/xsessions/xfce4_hidpi.desktop [Desktop Entry] Version=1.0 Name=Xfce4 Desktop (HiDPI) Comment=Use this session to run Xfce as your desktop environment on a HiDPI mon itor Exec=startxfce4_hidpi Icon= Type=Application ``` `startxfce4_hidpi` was a wrapper setting environment variables and was removed from the Xfce packages with the update to 4.13. So currently, it does not even start anymore. and I’ll remove the file from the distmaster.

Could it be, that this is an issue with xfce 4.13, which is a developer release?

Sure, it could be, but I do not know.

thomas · 2018-08-22T13:43:58Z

I've just stumbled over the nonexistant startxfce4_hidpi, I've written extra code for this case in the greeter -- Hmmmm.

Are the pool-PC's ok for scale testing? The small eizo at thehawk isn't.

pmenzel · 2018-08-22T13:48:53Z

On 08/22/18 15:43, Thomas Kreitler wrote: I've just stumbled over the nonexistant `startxfce4_hidpi`, I've written extra code for this case in the greeter -- Hmmmm.

Sorry, I forgot about it. Luckily it’s a generic for loop.

Are the pool-PC's ok for scale testing? The small eizo at thehawk isn't.

Good question. I do not think you can select the 2x, but logging in you should see if the panel is scaled or not.

thomas · 2018-10-01T08:35:51Z

I' ve checked the panel issues a little bit.
Machines where sigchld: gdm, sigusr2: lightdm.

Both failed to correctly apply 'window scaling' (Settings>Appearance>Settings>'Window scaling'), it looks like only one outof three subwidgets is scaled properly, also backswitching failes with layout errors.
So one might apply a killall -HUP xfce4-panel to get the panel back into a working state.

As for possible DBus issues, both machines allow connections to the panel, so no difference between the two setups (qdbus | grep -i panel shows the presence).

One way I found to get a neatly scaled panel is to start it under the Gtk-Debugger (GTK_DEBUG=interactive xfce4-panel), and scale the thing manually. NB this seems to apply for other parts of Xfce too, but I haven't checked it very deeply.

thomas · 2018-11-12T15:49:34Z

Latest observations concering gdm vs. lightdm:
Testing Xfce on sigchld / sigusr2 show no difference in the awkward scaling behaviour (not all widgets do resize, missing redraws when switching back to 1x)

thomas · 2018-11-14T13:13:55Z

Observations continued ...

Procedere: Toggle scaling 1x->2x->1x

This how the areas are named:
[app-buttons][pager][user]

user is the button showing the name and that provides 'logout', etc.
pager, obvious, the tiny windows
app-buttons, the things that represent the apps

Lightdm installed after dist:

[app-buttons] scales, rest not, layout messed up after reset to 1x

There was an interesting commit (Fix default size of new panels (Bug #14417), https://git.xfce.org/xfce/xfce4-panel/commit/?id=77e579478473d923fcf6c05a50a403f046dcea99).
Running the patched one:

Now [user] scales, but not the rest, layout restored after reset to 1x

Now rolling dice once more, running the latest panel from git:

[app-buttons] scales, rest not, layout messed up after reset to 1x, see above.

My conclusion, the panel code is still buggy, and seems to suffer from uninitialized portions.

thomas · 2018-11-30T07:17:58Z

How to proceed...
A new tag will be introduced: 'lightdm'. Via systemds' (!) ConditionPathExists /node/tags/lightdm either gdm or lightdm will handle graphical logins. This allows testing/improving lightdm without 'fighting' against the distmaster. One subproject is lightdms promised ability of handling VNC connects, what might be pretty useful (At least IMHO:).

wwwutz · 2018-11-30T07:22:33Z

A new tag will be introduced: 'lightdm'.
LGTM!

donald · 2018-11-30T09:42:08Z

Please say, when this solution (coexisting DMs with tag switch) is integrated into this pull request, so that we can test and merge it.

/etc/systemd/system/gdm.service is managed by mxtools, so !ConditionPathExists /node/tags/lightdm can (after a test) be added there. Should do no harm and should be done first.

thomas · 2018-11-30T10:13:26Z

Will start on this next week.

pmenzel · 2018-12-03T16:06:39Z

One subproject is lightdms promised ability of handling VNC connects, what might be pretty useful (At
least IMHO:).

By the way, GDM also supports XDMCP.

For our version 3.4.1 change /etc/gdm/custom.conf like below.

[security]
DisallowTCP=false

[xdmcp]
Enable=true

Restart GDM, and the command below works.

Xnest -query localhost -geometry 1280x1024 :1

See also: mariux64/bee-files#875 (comment)

Lightdm is enabled per host by providing the 'lightdm' tag in our hostconfig. Installation steps on distmaster: - install updated gdm.service (see mariux64/mxtools) - bee install lightdm-1.26.0-0.x86_64 (surprise:) - systemctl enable lightdm Conditions and installation tested on sigstkflt, sigill & sigint.

pmenzel reviewed Aug 22, 2018

View reviewed changes

thomas mentioned this pull request Sep 14, 2018

slick-greeter: a 'user interface' for lightdm #876

Merged

thomas added a commit to mariux64/mxtools that referenced this pull request Dec 11, 2018

gdm.service: Retreat if host is taged 'lightdm'

10c8715

See also: mariux64/bee-files#875 (comment)

thomas mentioned this pull request Dec 11, 2018

gdm.service: Retreat if host is taged 'lightdm' mariux64/mxtools#60

Merged

donald merged commit ec9dad8 into master Dec 11, 2018

lightdm: low dependency login/display manger #875

lightdm: low dependency login/display manger #875

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lightdm: low dependency login/display manger #875

lightdm: low dependency login/display manger #875

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