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    #1

    Cannot turn off the computer if more than one user is logged

    Hi all, just posting my first message on kubuntuforums and asking for help!

    I have a pretty fresh install of Kubuntu 13.04. The problem is the following:

    If more than one user is logged into the system, I cannot turn off the computer: it simply logout the user who has given the shutdown command and prompr a kdm window for the next login. All the existing X sessions remain active.
    To reproduce this behaviour, just log in and open the K menu ->leave -> switch user. Open a new session and log in with the same or another user, it is indifferent. Then K -> leave -> shut down. It simply exit from the X session. Moreover, on the next kdm screen that is presented, the shutdown and restart buttons don't work: you can click them a million times but nothing happens and no messages are displayed.

    I have compared this behaviour with that of a Arch Linux box, with the same version of KDE (4.10.5): here it works and, before shutting down, a popup asking to terminate the other active sessions is displayed, and the system shuts down correctly. So it is likely not to be a problem of KDE, but a kubuntu-related issue.

    Can someome verify this behaviour and confirm the problem?

    Thanks
    Stefano
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    #2
    I just tried this and found my self logged out (both sessions), but frozen at a blinking curser. I thought to try Ctrl+Alt+F1 to sudo reboot, but as soon as I hit the keys, the system proceeded to reboot for me.
    I do not personally use Kubuntu, but I'm the tech support for my daughter who does.
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      #3
      Originally posted by proffi View Post
      I have compared this behaviour with that of a Arch Linux box, with the same version of KDE (4.10.5): here it works and, before shutting down, a popup asking to terminate the other active sessions is displayed, and the system shuts down correctly. So it is likely not to be a problem of KDE, but a kubuntu-related issue.
      More likely, it's an implementation decision. The operating system really has no way to verify that you are the human behind both sessions. Therefore, both sessions need to be properly logged off.

      I'd say the Arch implementation presents a security risk. One standard user should not be able to force another standard user off the system -- that ought to be reserved for root only.
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        #4
        I'll bet it is s login manager thing. I do believe that the desired behavior is present using KDM, while the 'buntus are using lightdm. Luckily one can easily switch between different login mangers. If you install KDM, it will prompt you to choose which one you want to use .

        Sent from my HTC6435LVW using Tapatalk 4
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          #5
          Originally posted by claydoh View Post
          I'll bet it is s login manager thing. I do believe that the desired behavior is present using KDM, while the 'buntus are using lightdm. Luckily one can easily switch between different login mangers. If you install KDM, it will prompt you to choose which one you want to use .

          Sent from my HTC6435LVW using Tapatalk 4
          Thanks, it was an issue related to the login manager. I've installed KDM and now I've obtained the desired behaviour.


          Originally posted by SteveRiley
          More likely, it's an implementation decision. The operating system really has no way to verify that you are the human behind both sessions. Therefore, both sessions need to be properly logged off.

          I'd say the Arch implementation presents a security risk. One standard user should not be able to force another standard user off the system -- that ought to be reserved for root only.
          Your argument is valid, indeed.
          Anyway there is a strange behaviour in Lightdm: if only one user is logged, but other X sessions are left alive (for example because user have already logged off), the active user cannot turn off the computer: if he is logged in and tries to turn off he is prompted the login screen, and now, if he clicks on the turnoff button, it works.

          Thanks
          Stefano
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            #6
            Originally posted by proffi View Post
            Thanks, it was an issue related to the login manager. I've installed KDM and now I've obtained the desired behaviour.
            Huh, OK. Thanks for letting us know. I've never experimented with multiple users on any of my Linux computers. I'll go on record as saying that KDM's behavior is, IMHO, wrong. The system should never allow a non-privileged user to alter anything about another user's session. I may need to dig into the history and background of this some more.
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              #7
              KDM has many config options, both in system settings and its rc file. I do not remember for sure, but the admin user (the sudo user in our case) was the one who could have this power by default.
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                #8
                Originally posted by claydoh View Post
                KDM has many config options, both in system settings and its rc file. I do not remember for sure, but the admin user (the sudo user in our case) was the one who could have this power by default.
                Yep, the admin/root/$DEITY can certainly have this power. But J. Ordinary User shouldn't.
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