ROX-Session
A very simple session manager
by Thomas Leonard
Brief
ROX-Session is a simple and easy to use session manager. It is part of the ROX project, but can also be used on its own. ROX project home website:
ROX-Session sets up your desktop when you log in, and starts any applications you ask it to. It allows you to set various settings, such as the default font, cursor blinking and mouse behaviour.
It also allows you to choose a window manager, and change between window managers without logging out.
Conditions
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Please report any bugs to me, <tal197@users.sourceforge.net>.
The XSettings support code is taken from the XSettings sample implementation. The conditions for this code are:
Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Red Hat not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. Red Hat makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.
Instructions
Click on ROX-Session in a ROX-Filer window, or run the AppRun script manually:
$ ROX-Session/AppRun
ROX-Session will offer to manage your session in future. If you accept, it will create suitable .xsession and .xinitrc files for you and ask you to log out. When you log in again, ROX-Session will be running. You may need to choose 'Default' or 'Xsession' from your login screen's list of desktops. See below for instructions on adding ROX directly to this list.
** If ROX-Session fails to run (possibly with font errors), **
** try editing ROX-Session/AppRun and turn off XFT support. **
The first time you log in, ROX-Session asks you to choose a window manager. Select one from the list provided and click on 'Start window manager'. If the window mananger crashes, or you quit it, ROX-Session will ask you to choose again. If your preferred window manager isn't on the list then you can enter its name manually. Click on 'OK' to make the chosen window manager the default for future sessions. You can also adjust various other settings from this window.
When you want to logout, simply run ROX-Session a second time to display the logout box. This box also contains a 'Session Settings' button which takes you back to the options box, and the power management buttons (see below).
Halt/Reboot/Sleep
As well as logging out (which normally returns you to the login screen), you can get ROX-Session to perform other functions. These generally need to be configured before use, although the defaults may work for you.
Clicking on one of the buttons simple executes the corresponding command set in the Power section of the Options (Session Settings) box.
Halt
This should be a command which turns off the computer. On many systems
this can be simply 'halt', or 'shutdown -t now'. If normal users don't
have permission to run halt you can use sudo or xsu:
sudo halt
xsu -c '/sbin/halt' -u root
When using sudo, ensure that sudo allows the user to execute the
command without entering a password, since ROX-Session does not
provide a prompt.
Reboot
A command to reboot the computer. This can be simple 'reboot' or
'shutdown -t now -r'. sudo or xsu may need to be used, as above.
Suspend
A command to put the computer into power saving mode. The default
command 'xset dpms force off' simply turns the screen off.
APM users could try 'apm -s' to suspend, while users of the newer
ACPI could try 'echo 1 > /proc/acpi/sleep'.
Customising
To decide what programs to run when you login, ROX-Session tries to run the script <Choices>/ROX-Session/Login, where <Choices> is tried as:
~/Choices
/usr/local/share/Choices
/usr/share/Choices
until it finds the script. You can override this by setting the CHOICESPATH environment variable.
If no script is found then it runs the Login script inside the ROX-Session application directory instead. The default script will run all the programs in:
<Choices>/ROX-Session/AutoStart
If you want certain programs to be started automatically when you log in:
- Menu click on ROX-Session in a filer window and choose 'Auto Start...' from the menu.
- Symlink each application that you want to start into this directory (drag applications in with Control and Shift held down).
- You can also create script files in here if you want.
If you need even more control, copy the Login file from inside ROX-Session's application directory into Choices/ROX-Session and edit it there.
There is also a RunROX script which works in a similar way, but runs ROX-Filer with a panel and a pinboard set up. Unlike Login, this script should not exit. If it does, ROX-Session will offer to run it again. You can move this into Choices/ROX-Session to customise it, as with Login.
The SetupPanel script is used to create a default panel if none is set up. You shouldn't need to edit this, since for a single user it's easier to modify the panel directly, and for an admin or distribution you can put a suitable default in /usr/[local]/share/Choices/ROX-Filer/pan_Default.
Listing ROX in the login box
If you're using gdm (the GNOME display manager) then you can add ROX to the list of sessions like this:
- Go to /etc/gdm/Sessions.
- Copy the .xsession that ROX-Session created in your home directory into this directory, as 'ROX'.
- Run gdmconfig.
- Go to Expert -> Login sessions and check that 'ROX' is listed. Add it if not.
kdm users can use kcontrol to set things up in a similar way (but put the 'ROX' script in /usr/local/bin or similar).
Environment
In the .xsession script, before ROX-Session is started, ~/bin is added to the front of your PATH (if the ~/bin directory exists).
There are also a couple of lines in ROX-Session/AppRun to turn on anti-aliased font support. You may need to edit these lines to turn support off (if it doesn't work on your system, or you want the nasty old font system back).
Note: In GTK+-2.2, the new font system became the default. In GTK-2.4 it is likely that the old font system will no longer be available. Therefore, it would be better to fix any problems with the new font system now rather than just use the old one.
Errors
Because an error in the session system can stop you from logging in, ROX-Session has a number of safety measures:
- If the .xsession script can't find ROX-Session then it will look for a window manager on its own, and will also try to give you an xterm. It will also use xmessage to explain what has happened.
- If ROX-Session hasn't been compiled when you try to run it, it will try to compile itself first.
- If the Login script returns an error code then ROX-Session will run an xterm and display a suitable message. Run ROX-Session a second time to logout, as usual (quitting the xterm won't do it in this case).
Message display
Every process has an error stream that it can write to. All processes run by the Login script have their standard error output connected to ROX-Session's logging system.
These messages are displayed directly on the screen for five seconds, as well as being copied to ROX-Session's own standard error (where it often ends up in the file ~/.xsession-errors).
Click the left mouse button on the messages to hide them (until the next message is produced). Click the right mouse button to open a window showing recent messages (new messages appear here instead of being shown directly on the screen). You can also open this window by running ROX-Session again and using 'Session Settings' to show the Options window. There is a 'Show message log' button in the Messages section.
As well as using this for displaying error messages, you can write other things to it too, eg...
- Put
echo Loading Netscape... >&2 in Netscape's AppRun file to get a message letting you know it's loading, etc.
If you don't want to see errors from a program, you can redirect them elsewhere:
prog 2>/dev/null
sends stream 2 ('standard error') to the big bit-bucket in the sky. Complaining to the program's author is also a good move, as redirecting errors could make you miss something important.
Window manager list
You can edit the list of window managers that ROX-Session offers by copying the ROX-Session/WindowMans file as <Choices>/ROX-Session/WindowMans and editing it there.
This is mainly useful if you're a system administrator and you want to set the list for all your users. Only window managers found in $PATH will actually be displayed to the user.
What's a session manager?
The following is some background information about
session managers in general. This is provided for
interest only...
Most people use a program such as xdm (X Display Manager) to control their X server. xdm displays a graphical login prompt, logs you in, starts your X session and then, afterwards, resets the X server and does it again.
How does xdm know when you've finished?
Well, after xdm has verified your user name and password it runs a system-wide Xsession script as you. Try 'locate xdm/Xsession' to find the file on your system. When this script exits, xdm resets the X server and restarts the login process.
What does the Xsession script do?
It depends on your system, but usually it looks for an executable file called '.xsession' in your home directory (note - as the name starts with a dot it is hidden by default). If it finds one it runs it, otherwise it does some default stuff. Your '.xsession' script runs all the programs you want running on startup (such as a window manager, filer, xterm, etc). It runs all of these programs in the background except the last one, which it execs. Here's a simple example script (remember to make it executable!):
#!/bin/sh
twm &
xclock &
exec xterm
This runs the (ugly!) twm window manager and xclock in the background. It then replaces itself with the xterm process. You can now kill twm and xclock as you please, but when xterm quits your session is over. In this example, xterm is your session manager. Using xterm as a session manager isn't very smart...
Many people use a window manager as a session manager. However, this has a
couple of drawbacks:
1) You can't change your window manager without restarting your X session.
2) Window managers are quite complex programs and can crash from time-to-time.
If your session manager crashes then your X session is over!
What does ROX-Session do?
Very little. When you run it from your '.xsession' file it just loads, runs the Login script (as described above) and waits.
When you want to log out you simply run it a second time. The new copy sees that the first one is running and sends it a message. The first copy displays a box confirming that you want to log out and, if you say yes, quits. This causes your X session to be terminated. Save your data before logging out!!
!!!WARNING!!!
An incorrect .xsession file can prevent you from logging in!
Make sure you test it first, or are able to get a textual login
if needed (Ctrl-Alt-F1 on Linux, or try pressing F1 instead of
Return at the xdm prompt for a 'failsafe' xsession script).