Mir cannot open a tty when started by lightdm
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Light Display Manager |
Fix Released
|
High
|
Robert Ancell | ||
1.18 |
Fix Released
|
High
|
Robert Ancell | ||
lightdm (Ubuntu) |
Fix Released
|
High
|
Robert Ancell | ||
Xenial |
Fix Released
|
High
|
Robert Ancell |
Bug Description
[Impact]
LightDM reports the system compositor socket to Mir clients using the MIR_SOCKET variable. This stopped working in Mir 0.21. The Mir team says the correct variable is MIR_SERVER_
[Test Case]
1. Start LightDM with a Mir greeter
Expected result:
Greeter starts
Observed result:
Mir greeter fails to start. It is attempting to access the video drivers directly (i.e. not through a compositor).
[Regression Potential]
Risk of using LightDM with older version of Mir that doesn't support MIR_SERVER_
From mir-greeter.log (and with minor instrumentation from RAOF)
ERROR: QMirServer - Mir failed to start
qtmir.screens: ScreenControlle
qtmir.mir: MirServer created
qtmir.mir: Command line arguments passed to Qt: ("/usr/bin/unity8", "--mode=greeter")
ERROR: /home/josh/
Dynamic exception type: boost::
std::exception:
ERROR: /home/josh/
Dynamic exception type: boost::
std::exception:
/dev/tty0:
Failed to open read-only: Permission denied
Failed to open write-only: Permission denied
/dev/tty:
Failed to open read-only: No such device or address
Failed to open write-only: No such device or address
This occurs when trying to start the unity8 greeter under unity system compositor
Related branches
- LightDM Development Team: Pending requested
-
Diff: 105 lines (+10/-10)4 files modifiedsrc/mir-server.c (+2/-2)
src/unity-system-compositor.c (+2/-2)
tests/src/test-gobject-greeter.c (+3/-3)
tests/src/test-session.c (+3/-3)
Changed in lightdm: | |
assignee: | nobody → Robert Ancell (robert-ancell) |
Changed in lightdm: | |
status: | In Progress → Fix Committed |
Changed in lightdm: | |
status: | Fix Committed → Fix Released |
Changed in lightdm (Ubuntu Xenial): | |
status: | Triaged → Fix Committed |
description: | updated |
According to my system:
$ ls -l /dev/tty0
crw--w---- 1 root tty 4, 0 May 20 14:08 /dev/tty0
That makes sense. The greeter is running as the lightdm user so it shouldn't be able to open it.
Why is it trying? It should be running inside unity-system- compositor right?