Non-root execution via gksu requires -k to pass required environment

[javabrett]

$ dpkg-query -W mintdrivers
mintdrivers 1.1.6

Something may have changed in recent times to require environment to be passed to Python Gtk main, and such environment is not passed by-default when running as non-root via the script-initiated gksu, because it does not pass the -k flag. The result is that the above version now exits silently status 133.

Adding -k will fix this. As a workaround, you can run gksu manually:

$ gksu -k /usr/lib/linuxmint/mintDrivers/mintDrivers.py

[clefebvre]

Hi,

I can't reproduce this issue. What environment do you test this with?

Also, can you describe the issue from a user point of view? You mean the driver manager doesn't actually start? Or if it does, what is the impact of the missing environment?

[javabrett]

System:

$ lsb_release -a
No LSB modules are available.
Distributor ID: LinuxMint
Description:    Linux Mint 17.1 Rebecca
Release:    17.1
Codename:   rebecca

$ dpkg-query -W mintdrivers gksu
gksu    2.0.2-6ubuntu2
mintdrivers 1.1.6

Symptoms are that having selected Driver Manager from the menu, you get the gksu prompt, enter a valid password, then nothing. If you instead run mintdrivers from a terminal, same thing, the window never appears. If you instead run:

$ /usr/lib/linuxmint/mintDrivers/mintDrivers.py
$ echo $?
133

Running in a root shell gives a hint on what environment it might be missing:

# /usr/lib/linuxmint/mintDrivers/mintDrivers.py

(mintDrivers.py:690): Gdk-ERROR **: error: XDG_RUNTIME_DIR not set in the environment.

Trace/breakpoint trap

Finally, if you run xhost+ as the current user, then sudo su - for a root shell, to get a good launch you need to run (now as root) e.g.:

DISPLAY=:0 XDG_RUNTIME_DIR=/run/user/1000 /usr/lib/linuxmint/mintDrivers/mintDrivers.py

This might relate to my /etc/sudoers, although I thought it was more permissive on environment than the default, retaining proxies:

Defaults    env_keep = "http_proxy https_proxy"

Adding DISPLAY and XDG_RUNTIME_DIR there is also a workaround.

If you are unable to reproduce this problem for 1.1.6, then I guess it must be that somehow these environment variables are being passed through gksu, perhaps related to a permissive env_keep?

[clefebvre]

Hmm.. I think it might relate to mdm.. let me get back to you on this.

[javabrett]

I haven't mentioned all of the significant parts of my sudoers:

Defaults        env_keep = "http_proxy https_proxy"
Defaults        env_reset
Defaults        mail_badpass
Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

But it doesn't seem to make any difference if env_reset is removed ... something seems convinced it needs to scrub DISPLAY and XDG_RUNTIME_DIR.

Should we be running gksudo instead of gksu? They symlink to the same binary, but have arg0 logic as well as reading from gconf. I also read that they might be deprecated in favour of pkexec.

[javabrett]

As an alternative to adding -k, we could simply pass the known-required environment on the command-line.

[javabrett]

Exact cause still unknown, but this seems to be a fairly broad problem, and has started popping-up for me with other commands. As you suggest, likely related to X or window-manager.

E.g. https://forums.linuxmint.com/viewtopic.php?t=171159

[xenopeek]

While mintdrivers still uses gksu this issue doesn't appear to have been caused by the use of that. Indeed, running /usr/lib/linuxmint/mintdrivers/mintdrivers.py from a root shell does not give the XDG_RUNTIME_DIR not set in the environment it did above. The code has also seen some changes since this issue was reported.