.. _configuration_customizing_user_session: Customizing the User's Session ------------------------------ In this section, we will describe how the session startup in ThinLinc can be customized. .. _configuration_session-startup-bigpicture: Session startup - the big picture ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The session setup is constructed to be easy to use and configure yet still easy to customize for advanced use cases. .. _configuration_vsm-server-session-setup: .. figure:: images/vsm-server-session-startup.svg Session Startup Procedure - on VSM Server In :numref:`configuration_vsm-server-session-setup`, shows a (simplified) description of what happens on the VSM Server when a client connects to login: - The VSM Server checks if the user has an existing session. - If a session exists, VSM Server contacts the VSM Agent running on the host where the session is running, and asks it to verify that the session is still alive. - If the session was alive, VSM Server runs any scripts placed in :file:`/opt/thinlinc/etc/sessionreconnect.d`. When all such scripts are completed, session information is returned to the client. The client proceeds by contacting the agent on which the session is running. - If the existing session was not alive, or if there were no existing session at all, VSM Server finds out which VSM Agent has the least load, and contacts this agent to request a new session. - When the agent responds that a new session has been created, VSM Server runs any scripts placed in :file:`/opt/thinlinc/etc/sessionstartup.d`. When all such scripts are completed, session information is sent back to the client. The client proceeds by contacting the agent on which the session was started. .. _configuration_scripts_startup_reconnect: Scripts run at session startup/reconnect ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Scripts in :file:`/opt/thinlinc/etc/sessionstartup.d` and :file:`/opt/thinlinc/etc/sessionreconnect.d` are run by the root user, on the VSM Server. Session information will not be sent back to the client until these scripts have completed. This makes it possible to ensure that commands have been run before the client connects to the VSM Agent. If background execution is desired, place the command to be run in the background and make sure all file descriptors are closed. Here's an example on how to execute a script in the background. .. code:: bash ${TLPREFIX}/sbin/tl-limit-printers < /dev/null > /dev/null 2>&1 & .. _configuration_session-startup-vsmagent: Session startup on VSM Agent ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. _configuration_session-startup-vsmagent-figure: .. figure:: images/session-startup.svg Session Startup Procedure - on VSM Agent :numref:`configuration_session-startup-vsmagent-figure` outlines what happens when an VSM Agent is contacted by VSM Server to request a new session. In detail, the following happens: 1. The VSM agent on the machine where the session will reside executes the script :file:`/opt/thinlinc/etc/xsession`. 2. The file :file:`/opt/thinlinc/etc/xsession` is a shell script that can be customized by advanced users. In its standard version, as delivered with ThinLinc, it will check if there is a file named :file:`~/.thinlinc/xstartup` in the user's home directory. If there is such a file, it will be executed. If no such file exists, the file :file:`/opt/thinlinc/etc/xstartup.default` is executed instead. See :ref:`configuration_profiles-xstartup` for a description of the standard behaviour of this file. This system allows for experienced users to customize how their session startup should work by editing the file :file:`~/.thinlinc/xstartup`. On the other hand, at sites where users should not be able to customize their system startup, :file:`/opt/thinlinc/etc/xsession` can be modified so that it doesn't try to execute user-specific xstartup-files. The standard setup should however suit the needs of the majority of installations. .. _configuration_profiles-xstartup: Profiles and the standard xstartup.default file ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ThinLinc allows for different "profiles" when starting up a user session. The users will be presented with a menu after logging in, where they can choose for example between a desktop suited for engineering users, a desktop suited for the marketing department or a Windows desktop. The example configuration files that are delivered with ThinLinc have several different alternatives, however only those sessions that are actually available on the system are displayed. This is just an example configuration, meant to be customized for each individual ThinLinc installation. .. _configuration_profile-setup-figure: .. figure:: images/profiles-xstartup.svg The ThinLinc profiles and xstartup.default As described in :ref:`configuration_session-startup-bigpicture`, :file:`/opt/thinlinc/etc/xstartup.default` is executed if there is no :file:`~/.thinlinc/xstartup` for the user. This file, in its unmodified version as delivered with ThinLinc, executes three steps, as outlined in :numref:`configuration_profile-setup-figure`. 1. The command :program:`tl-run-xstartup.d` is executed, which causes all files in :file:`/opt/thinlinc/etc/xstartup.d/` to be executed. Files that have filenames ending with :file:`.sh` will be **sourced** as shell scripts. Other files are executed normally. This way, environment variables that persist down to the session command can be set in :file:`*.sh` files. If a specific execution order is needed for the scripts in the :file:`xstartup.d/` directory, let the names of the scripts begin with numbers, where a script with a lower number will be executed before one with a higher number. For example :file:`10setuphomedir` will be executed before :file:`20copyfiles`. By default, the script :file:`/opt/thinlinc/etc/xstartup.d/20-tl-select-profile.sh` will invoke :program:`tl-select-profile`, to let the user choose among the possible profiles. See :ref:`configuration_config-profiles` for documentation on how to setup profiles. If only one profile is available, :program:`tl-select-profile` will select it without asking the user. The environment variable :environ:`TLPROFILE` is set to the name of the selected profile. Worth noting is that the environment variable :environ:`TLPROFILE` is available when running the scripts in :file:`xstartup.d`, for decisions based on what profile will be run. 2. The command :program:`tl-run-profile` is run. This runs the commands associated with the selected profile, for example :command:`startkde` to start a KDE session. 3. When the commands run by :program:`tl-run-profile` exits, :file:`xstartup.default` runs the command :program:`tl-run-xlogout.d` which runs scripts and commands located in the directory :file:`/opt/thinlinc/etc/xlogout.d`. The same information that applies to files in :file:`xstartup.d` (as documented in step 1. above) applies to files in this directory. .. note:: Scripts in :file:`/opt/thinlinc/etc/xstartup.d` and :file:`/opt/thinlinc/etc/xlogout.d` are run **on the agent**, with the same rights as the user owning the session. .. _configuration_start_program: Session Startup with a Client Supplied Start Program ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If the client has requested that the session should be started with a command supplied by the client, VSM agent will set the environment variable :environ:`TLCOMMAND` to this command. In this case, the profile selection dialog will be disabled and :program:`tl-run-profile` will execute the command specified by the client, instead of a profile command. To disable client supplied start programs, create the file :file:`/opt/thinlinc/etc/xstartup.d/00-no-startprog.sh`, containing: .. code:: sh unset TLCOMMAND .. _configuration_config-profiles: Configuring available profiles ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The profiles choosable via the :program:`tl-select-profile` command are configured via Hiveconf, under the :servconf:`/profiles` path. The default configuration includes a number of examples. If the |default| parameter is present, it specifies the default profile. The profile chooser will have this entry selected when it starts, and it may also be used automatically for some error conditions. .. |default| replace:: :servconf:`default ` The |order| parameter selects which profiles should be available for selection, and the order in which they are displayed. This is a space-separated list. .. |order| replace:: :servconf:`order ` If the |show_intro| parameter is true, a configurable introduction text will be displayed and requires user input to proceed with the logon process. The |introduction| parameter is a text that will be displayed if introduction is shown. This text block also supports `Pango Markup`_ format styling for a fancier text layout. .. |show_intro| replace:: :servconf:`show_intro ` .. |introduction| replace:: :servconf:`introduction ` Each profile is defined under a section named :servconf:`/profiles/\`. For most desktop environments only the |xdg_session| parameter needs to be configured. For custom profiles more values need to be specified, mainly |cmdline|. Please see :ref:`configuration_profiles` for more details on the available options. .. |xdg_session| replace:: :servconf:`xdg_session /xdg_session>` .. |cmdline| replace:: :servconf:`cmdline /cmdline>` .. _Pango Markup: https://docs.gtk.org/Pango/pango_markup.html#pango-markup Configuring different Linux Desktops based on the selected profile ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Please read :ref:`tldc` for documentation on how to configure different desktops with for example different menu and desktop icons depending on what profile were selected. Speeding up Session Startup ~~~~~~~~~~~~~~~~~~~~~~~~~~~ If a user has a complicated session startup with many time-consuming operations, it can take quite a while before the user's desktop environment (for example KDE or Gnome) begins to start. Prime examples of when this happens is when mounting local drives, or when mounting some shared directories from a Netware server. One way of speeding up this process is to execute some of the operations in the background. Most often, there is no need to mount the local drives before starting KDE, because it takes longer time to start KDE than it takes to mount the local drives. The two operations can easily run in parallel. The same goes for the example of mounting shared directories. The easiest way to accomplish this is to add an & sign after commands run by scripts in :file:`/opt/thinlinc/etc/xstartup.d`. Make sure that commands that must be run before starting the window environment are run sequentially. For example, configuring desktops via TLDC must be done before starting KDE. Configuring the language environment on the server based on the client language ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ThinLinc client reports the language settings on the client side when requesting a session. This can be used to configure the language on the server side. The idea is that in an environment where several languages are in use, a user could automatically get their preferred language based on what their client computer is configured for. To activate this, a symlink needs to be created: .. code:: console $ sudo ln -s /opt/thinlinc/libexec/tl-set-clientlang.sh \ /opt/thinlinc/etc/xstartup.d/00-tl-set-clientlang.sh Also, make sure no other parts of the startup environment are trying to set the :environ:`LANG` variable. For example, on Fedora, the files :file:`/etc/profile.d/lang.sh` and :file:`/etc/profile/lang.csh` will override the :environ:`LANG` variable set by :program:`tl-set-clientlang.sh`.