Session Manager is responsible for starting the desktop and automatically saving and restoring running applications, colors, fonts, mouse behavior, audio volume, and keyboard click.
Using Session Manager, you can:
Customize the initial session for all desktop users
Customize the environment and resources for all desktop users
Change the session startup message
Change parameters for session startup tools and daemons
Customize desktop color usage for all users
A session is the collection of applications, settings, and resources present on the user's desktop. Session management is a set of conventions and protocols that enables Session Manager to save and restore a user's session. A user is able to log in to the system and be presented with the same set of running applications, settings, and resources as were present when the user logged off. When a user logs in to the desktop for the first time, a default initial session is loaded. Afterward, Session Manager supports the notion of a current and a home session.
When a user logs in to the desktop for the first time, Session Manager will generate the user's initial session using system default values. By default, the File Manager and Introduction to the Desktop, a help volume, will start.
The user's running session is always considered the current session, whether restored upon login from a saved home session, a saved current session, or the system default initial session. Based on the user's Style Manager Startup settings, when the user exits the session, Session Manager automatically saves the current session. When the user next logs in to the desktop, Session Manager restarts the previously saved current session, meaning that the desktop will be restored to same state as when the user last logged out.
You can also have the desktop restored to the same state every time the user logs in, regardless of its state when the user logged out. The user can save the state of the current session and then, using the Style Manager Startup settings, have Session Manager start that session every time the user logs in.
To run a specific session for a specific display, a user can create a display-specific session. To do this, the user can copy the HomeDirectory/.dt/sessions directory to HomeDirectory/.dt/display, where display is the real, unqualified host name (for example, pablo:0 is valid, pablo.gato.com:0 or unix:0 is not). When the user logs in on display pablo:0, Session Manager will start that display-specific session.
Session Manager is started through /usr/dt/bin/Xsession. When the user logs in using the Login Manager, Xsession is started by default.
Optionally, the user can log in using the traditional character mode (getty) login, and start Session Manager manually using tools that start an X server, such as xinit. For example: xinit /usr/dt/bin/Xsession.
When Session Manager is started, it goes through the following steps to start the user's session:
Gathers available applications
Optionally sources HomeDirectory/.profile or HomeDirectory/.login
Starts the session applications
The following sections describe the steps listed above.
At session startup, the Xsession script sources the user's HomeDirectory/.dtprofile script. The HomeDirectory/.dtprofile script is a /bin/sh or /bin/ksh script that enables users to set up environment variables for their sessions. For more information on setting up environment variables, see "Additional Session Startup Customizations".
If the HomeDirectory/.dtprofile script does not exist, such as when a user is logging in to the desktop for the first time, Xsession will copy the desktop default sys.dtprofile to HomeDirectory/.dtprofile.
The desktop default is /usr/dt/config/sys.dtprofile. To customize the sys.dtprofile script, copy sys.dtprofile from /usr/dt/config to /etc/dt/config and edit the new file.
After sourcing the HomeDirectory/.dtprofile script, the Xsession script sources the Xsession.d scripts. These scripts are used to set up additional environment variables and start optional daemons for the user's session. The default Xsession.d scripts are:
0010.dtpaths--documents customizable desktop search paths
0020.dtims--starts optional input method server
0030.dttmpdir--creates per-user, per-session temporary directory
0040.xmbind--sets up $XMBINDDIR to desktop default
There may be additional vendor-specific scripts in Xsession.d.
Xsession first sources all files in the /etc/dt/config/Xsession.d directory, followed by those in the /usr/dt/config/Xsession.d directory.
The desktop default Xsession.d scripts are located in the /usr/dt/config/Xsession.d directory. To customize an Xsession.d script, copy the script from /usr/dt/config/Xsession.d to /etc/dt/config/Xsession.d and edit the new file. You must have execute permission to perform this task.
Also, to have Xsession automatically source a script of your own, copy it to /etc/dt/config/Xsession.d.
When you modify or create an Xsession.d script, make sure that any foreground commands you issue are of short duration, as the time taken by the command will directly affect session startup time. If a foreground command does not exit, the session startup will hang. Commands run in an Xsession.d script that you want to remain running for the duration of the session should be run in the background.
After sourcing HomeDirectory/.dtprofile and the Xsession.d scripts, Xsession displays a welcome message that covers the screen. You can customize the welcome message displayed, or turn off the message entirely. The dthello client is used to display the message.
To alter the message text, change the dthello options by modifying the dtstart_hello[0] variable.
To change dtstart_hello[0], create an /etc/dt/config/Xsession.d script that sets the new value. To display the message of the day for all users, create an executable sh or ksh script, for example /etc/dt/config/Xsession.d/myvars, and set dtstart_hello[0] as follows:
dtstart_hello[0]="/usr/dt/bin/dthello -file /etc/motd &"
Similarly, users can change the welcome message for their sessions by setting dtstart_hello[0] in HomeDirectory/.dtprofile.
To turn off the welcome message, set dtstart_hello[0]=" ".
For more information about dthello, see the dthello man page.
The desktop search paths are created at login by dtsearchpath. There are two categories of environment variables used by dtsearchpath:
Input Variables--System-wide and personal environment variables whose values are set by the system administrator or end user.
Output Variables--Variables created and assigned values by dtsearchpath. The value of each variable is the search path for the desktop session.
To alter the command-line options of dtsearchpath, modify the dtstart_searchpath variable. To change the dtstart_searchpath variable for all users, create an executable sh or ksh script (for example /etc/dt/config/Xsession.d/myvars), and set dtstart_searchpath as follows:
dtstart_searchpath="/usr/dt/bin/dtsearchpath"
Users can similarly change the dtsearchpath options for only their own sessions by setting dtstart_searchpath in HomeDirectory/.dtprofile.
For more information about dtsearchpath, see Chapter 9, Desktop Search Paths. For more information about dtsearchpath options, see the dtsearchpath man page.
The next step after setting up the desktop search paths is to gather available applications using dtappgather. To alter the command-line options of dtappgather, modify the dtstart_appgather variable. To change the dtstart_appgather variable for all users, create an executable sh or ksh script (for example /etc/dt/config/Xsession.d/myvars), and set dtstart_appgather as follows:
dtstart_appgather="/usr/dt/bin/dtappgather &"
Users can similarly change the dtappgather options for only their own sessions by setting dtstart_appgather in HomeDirectory/.dtprofile.
For more information about dtappgather options, see the dtappgather(4) man page.
Xsession is able to source a user's traditional HomeDirectory/.profile or HomeDirectory/.login scripts. By default this capability is disabled. To tell Xsession to source the .profile or .login script, set DTSOURCEPROFILE
to true.
To change DTSOURCEPROFILE
for all users, create an /etc/dt/config/Xsession.d script that sets the new value. To set DTSOURCEPROFILE
to true for all users, create an executable sh or ksh script, for example /etc/dt/config/Xsession.d/myvars, and set DTSOURCEPROFILE
as follows:
DTSOURCEPROFILE=true
Users can similarly change DTSOURCEPROFILE
for their own sessions by setting DTSOURCEPROFILE
to true in HomeDirectory/.dtprofile.
The ToolTalk messaging daemon, ttsession, enables independent applications to communicate with each other without having direct knowledge of each other. Applications create and send ToolTalk messages to communicate with each other. ttsession communicates on the network to deliver messages.
To alter the command-line options of ttsession, modify the dtstart_ttsession variable. To change the dtstart_ttsession variable for all users, create an executable sh or ksh script (for example /etc/dt/config/Xsession.d/myvars), and set dtstart_ttsession as follows:
dtstart_ttsession="/usr/dt/bin/ttsession -s"
Users can similarly change the ttsession options for their own sessions by setting dtstart_ttsession in HomeDirectory/.dtprofile.
For more information about ttsession options, see the ttsession man page. For more information on ttsession, see Common Desktop Environment: ToolTalk Messaging Overview.
At this point, Xsession starts /usr/dt/bin/dtsession, which continues the session startup process.
Session Manager uses the X server RESOURCE_MANAGER
property to make desktop resources available to all applications. Session Manager loads the RESOURCE_MANAGER
by:
Loading the system default resources
Merging any system-wide resources specified by the system administrator
Merging any user-specified resources
The desktop default resources can be found in /usr/dt/config/language/sys.resources. These resources will be made available to each user's session via the RESOURCE_MANAGER
property. This
file should not be edited, as it is overwritten upon subsequent desktop installations.
You can augment the system default resources by creating /etc/dt/config/language/sys.resources. In this file, you can override default resources or specify additional resources for all desktop users. Since this file is merged into
the desktop default resources during session startup, only new or updated resource specifications should be placed in this file. Resources specified in this file will be made available to each user's session through the RESOURCE_MANAGER
property. Resources
specified in this file take precedence over those specified in the desktop default resource file.
Users can augment the desktop default and system-wide resources using their HomeDirectory/.Xdefaults file. Resources specified in this file will be made available to that user's session through the RESOURCE_MANAGER
property. Resources specified in this file take precedence over those specified in the desktop default or system administrator resource files.
The X Toolkit Intrinsics utility specifies that it will load resources for an application from either RESOURCE_MANAGER
or from HomeDirectory/.Xdefaults, but not both. Ordinarily, this would mean that the
user's HomeDirectory/.Xdefaults file would be ignored. However, Session Manager accommodates HomeDirectory/.Xdefaults by merging it into the RESOURCE_MANAGER
at session
startup as described above. If a user changes HomeDirectory/.Xdefaults, the changes will not be visible to new applications until the user invokes the Reload Resources action. The Reload Resources action will instruct Session Manager to reload the RESOURCE_MANAGER
with the default, system-wide, and user-specified resources. This makes changes to the system-wide and personal resource files available to applications.
For more information see:
The dtresourcesfile(4) man page
Session Manager serves as the color server for the desktop and provides the following set of dtsession resources that can be used to configure it.
foregroundColor--controls whether a pixel is allocated for the foreground color
dynamicColor--specifies whether read-only colors are allocated
shadowPixmaps--specifies whether colors are allocated for top shadow or bottom shadow
colorUse--limits color allocation
writeXrdbColors--specifies whether the *background and *foreground resources are placed in the resource database
You can set color server resources for all users by creating /etc/dt/config/language/sys.resources and specifying the color server resources in that file.
Users can similarly set color server resources for their own sessions by specifying color server resources in HomeDirectory/.Xdefaults.
For more information about setting color server resources, see "Administering Colors".
Session Manager is responsible for starting Workspace Manager. By default /usr/dt/bin/dtwm is started. An alternate window manager can be specified with the wmStartupCommand resource.
You can specify an alternate window manager for all users by creating /etc/dt/config/language/sys.resources and specifying the full path name and options for the window manager with the Dtsession*wmStartupCommand resource in that file.
Users can similarly specify an alternate window manager for their own sessions only by specifying the Dtsession*wmStartupCommand resource in HomeDirectory/.Xdefaults.
For more information about the Window Manager, see Chapter 16, Customizing the Workspace Manager.
At session startup, Session Manager will restart any applications that were saved as part of the session. The system default set of applications to be restored as part of the user's initial session can be found in /usr/dt/config/language/sys.session. This file should not be edited as it will be unconditionally overwritten upon subsequent desktop installations.
For more information, see the dtsessionfile(4) man page.
A system administrator can replace the set of applications that are started as part of the user's initial session by copying /usr/dt/config/language/sys.session to /etc/dt/config/language/sys.session and modifying the latter file. Unlike the resource files, this file will be used as a complete replacement for the desktop default file, so you can make a copy of the system default file and make any necessary modifications.
This section covers:
Setting environment variables
Setting resources
Using display-dependent sessions
Running scripts at login
Recovering a back-up session
To set system-wide environment variables, create a file in the /etc/dt/config/Xsession.d directory that sets and exports the variable.
For example, if you create an executable ksh script, /etc/dt/config/Xsession.d/myvars, containing:
export MYVARIABLE="value"
then the variable MYVARIABLE
will be set in each user's environment at the next login.
For example:
export MYVARIABLE="value"
sets the variable MYVARIABLE
in each user's environment at the next login.
Session Manager does not automatically read the .profile or .login file. However, it can be configured to use these files; see "Optionally Sourcing the .profile or .login Script".
To set system-wide resources, add the resources to the file /etc/dt/config/language/sys.resources. (You may have to create the file.)
.dtprofile only supports /bin/sh or /bin/ksh syntax.
For example, if in /etc/dt/config/C/sys.resources you specify:
AnApplication*resource: value
then the resource AnApplication*resource will be set in each user's RESOURCE_MANAGER
property at the next login.
To set personal resources, add the resources to the file HomeDirectory/.Xdefaults.
You can set display-specific resources for all desktop users on the system. Also, users can set display-specific resources limited to their own session. This enables you to specify resources depending upon which display the user uses to log in to the desktop.
To set display-specific resources for all desktop users on the system, create the file /etc/dt/config/language/sys.resources that specifies the display-specific resources.
To set personal display-specific resources, specify the resource in HomeDirectory/.Xdefaults.
You delimit these resources by enclosing them in cpp conditional statements. A DISPLAY_
displayname macro is defined depending upon the value of the $DISPLAY
variable. This is done by converting
all . (period) and : (colon) characters to _ (underscores), stripping off any screen specification, and finally prefixing DISPLAY_
to the result.
For example, a $DISPLAY
of :0 would be DISPLAY_0
, and a $DISPLAY
of blanco.gato.com:0.0 would be DISPLAY_blanco_gato_com_0.
The resulting value can be used as part of a cpp test in a session resource file. For example, if in /etc/dt/config/C/sys.resources you specify:
Myapp*resource: value
#ifdef DISPLAY_blanco_gato_com_0 Myapp*resource: specialvalue1 #endif
#ifdef DISPLAY_pablo_gato_com_0 Myapp*resource: specialvalue2 #endif
the resource MyApp*resource will be set in RESOURCE_MANAGER
to specialvalue1 when the user logs in on display blanco.gato.com:0; specialvalue2 when the user logs in on pablo.gato.com:0; and value when the user logs in on another display.
You can specify alternate applications to start as part of a user's initial session.
Copy /usr/dt/config/language/sys.session to /etc/dt/config/language/sys.session.
Modify the new sys.session file.
Each entry in sys.session appears as:
dtsmcmd -cmd command_and_options
To start an additional application as part of a user's initial session, specify a new sys.session entry with a full path name. For example, to start /usr/bin/X11/xclock as part of a user's initial session, add an xclock entry to /etc/dt/config/C/sys.session:
# # Start up xclock... # dtsmcmd -cmd "/usr/bin/X11/xclock -digital"
A user can set up a display-specific session to tune a session to a particular display.
Copy the HomeDirectory/.dt/sessions directory to HomeDirectory/.dt/display where display is the real, unqualified host name (pablo:0 is valid, pablo.gato.com:0 or unix:0 is not).
For example, to create a display-specific session for display pablo.gato.com:0:
cp -r HomeDirectory/.dt/sessions HomeDirectory/.dt/pablo:0
When the user next logs in on display pablo.gato.com:0, the Session Manager will start that display-specific session.
Users can specify that additional commands be started when they log in to their desktop sessions. This is useful for setting up X settings that are not saved by Session Manager. For example, the user can use xsetroot to customize the root (workspace) pointer. Another use would be to start applications that are unable to be saved and restored by Session Manager. If an application will not restart when the session is restored, the user can start the client using this method.
Generally this file is a script and must have execute permission. Processes started in sessionetc should be run in the background.
Do not use sessionetc to start clients that are automatically restored by Session Manager. Doing so can cause multiple copies of the application to be started. You may not be able to see the copies immediately because the windows may be stacked on top of one another.
A companion file to sessionetc is sessionexit. Use sessionexit to perform some operation at session exit that is not handled by Session Manager.
Create the file HomeDirectory/.dt/sessions/sessionexit containing the commands.
Like sessionetc, this file is usually a script with execute permission.
When Session Manager saves a session, the session information is stored in the HomeDirectory/.dt/sessions directory or in the HomeDirectory/.dt/display directory if using a display-specific session. In these directories, Session Manager creates a subdirectory named current or home to store information for the respective current or home session. Before the session information is stored, Session Manager makes a backup of the prior session with that name and stores it in current.old or home.old.
Log in using the Failsafe Session or Command Line Login from the login screen.
Copy the backup session directory to the active name. For example, to recover the backup home session:
cp -r HomeDirectory/.dt/sessions/home.old \ HomeDirectory/.dt/sessions/home
Display-specific sessions can be recovered in the same manner.
Session Manager logs each user's session startup progress in this file.
/usr/dt/bin/Xsession
/usr/dt/config/Xsession.d/*
/usr/dt/bin/dtsession
/usr/dt/bin/dtsession_res
HomeDirectory/.dt/sessions/current
HomeDirectory/.dt/sessions/home
HomeDirectory/.dt/display/current
HomeDirectory/.dt/display/home