KDE Kiosk Mode
starting kcalc with the Precision group set as immutable makes changing these values impossible. Figures 3 and 4 show the difference between the locked and unlocked kcalc Precision settings.
Finally, the whole configuration file for the application can be made immutable by placing a [$i] at the very top of the file. This immutable mark cascades to all group and key/value pairs contained within the file. Setting the configuration file to immutable in this fashion completely disallows any changes made to an application's configuration.
Alternatively, if the KDE application does not have write access to the configuration file, it also is considered to be an immutable configuration file. This file permission restriction can be set directly on configuration files in the KDEHOME directory to prevent a user from editing the configuration.
For example, saving a non-writable kickerrc file restricts users from making any changes to the kicker panel. Many other KDE applications follow a similar procedure, though a restart of the application may be required in order for it to re-read its new configuration.
On top of being able to lock configuration items for users, administrators also can remove the functionality of certain actions users can perform. An action is simply something the user can perform, such as File→New. Because most KDE applications provide common actions, predefined standard action restrictions are easy to lock down. Program action restrictions are configured in the kdeglobals file, located in the same configuration directory structure noted above.
The following code snippet disables the standard Help menu available from the main toolbar of KDE applications:
... [KDE Action Restrictions][$i] action/help=false ...
Another option is disabling the Bookmarks feature of Konqueror. This can be accomplished like this:
... [KDE Action Restrictions][$i] action/bookmarks=false ...
Not all action restrictions have to be menu items. For example, the following snippet disables any options that require root access:
... [KDE Action Restrictions][$i] user/root=false ...
Many more actions can be set. A more complete list can be found in the kiosk documentation. Many of the actions are standard across KDE applications. Some applications, however, provide their own local actions, which can be restricted as well. Some of the more interesting actions are:
print/system: disables the ability to select the printing system.
shell_access: disables ability to start up a shell.
logout: disables user logouts.
run_command: disables Alt-F2 run command.
lineedit_text_completion: disables lineedits from remembering previous entries for partial text completion.
On top of configuration files, KDE applications utilize other types of resources in the KDEDIRS directories. Similar to the configuration file examples above, these resources are extended by resource files installed in KDEHOME. KDE provides the ability to restrict access to these types of files as well. This configuration information is stored in the kdeglobals configuration file. For example, the following kdeglobals snippet limits users' ability to add and utilize custom icon sets other than the ones already existing in an upper-level resource directory:
... [KDE Resource Restrictions][$i] icon=false ...
A list of resource types defined by KDE is shown in Table 1.
Table 1. Resource Types
Practical Task Scheduling Deployment
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
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|The Firebird Project's Firebird Relational Database||Jul 29, 2016|
|Stunnel Security for Oracle||Jul 28, 2016|
|SUSE LLC's SUSE Manager||Jul 21, 2016|
|My +1 Sword of Productivity||Jul 20, 2016|
|Non-Linux FOSS: Caffeine!||Jul 19, 2016|
|Murat Yener and Onur Dundar's Expert Android Studio (Wrox)||Jul 18, 2016|
- The Firebird Project's Firebird Relational Database
- Stunnel Security for Oracle
- My +1 Sword of Productivity
- SUSE LLC's SUSE Manager
- Non-Linux FOSS: Caffeine!
- Managing Linux Using Puppet
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- Parsing an RSS News Feed with a Bash Script
- Google's SwiftShader Released
- Doing for User Space What We Did for Kernel Space
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This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide