vasilito
cf12defd28
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
97 lines
3.4 KiB
Markdown
97 lines
3.4 KiB
Markdown
KConfig Entry Options {#options}
|
|
=====================
|
|
|
|
KConfig provides various options that can alter how it interprets configuration
|
|
entries on a per-entry, per-group or per-file basis. Note that these are not
|
|
supported by other configuration frameworks, and so should not be used in files
|
|
that are intended to be used by applications that do not use KConfig (such as
|
|
application desktop files).
|
|
|
|
|
|
Immutable Entries
|
|
-----------------
|
|
|
|
KConfig's cascading configuration mechanism usually causes values from earlier,
|
|
"global" configuration files to be overridden by later, "local" ones.
|
|
Typically, the system administrator might set global defaults, and a user might
|
|
override them in their local configuration files.
|
|
|
|
However, KConfig provides a way to lock down configuration values, so that the
|
|
global settings override the local ones. This allows system administrators to
|
|
restrict the values a user can set for an entry, group of entries or an entire
|
|
configuration file.
|
|
|
|
This is important for Kiosk authorization (see the KAuthorized namespace),
|
|
which allows parts of the user interface to be locked down.
|
|
|
|
Configuration entries can be marked as immutable with the `$i` option. This can
|
|
be done on a per-entry basis:
|
|
|
|
[MyGroup]
|
|
someKey[$i]=42
|
|
|
|
on a per-group basis (which will prevent any attempts to modify entries in the
|
|
group at all in later files):
|
|
|
|
[MyGroup][$i]
|
|
someKey=42
|
|
|
|
or for an entire file by putting `[$i]` at the start of the file:
|
|
|
|
[$i]
|
|
[MyGroup]
|
|
someKey=42
|
|
[MyOtherGroup]
|
|
someOtherKey=11
|
|
|
|
Once this is done, the immutable entries or groups cannot be overridden by later
|
|
files of the same name (and, if the file is immutable, later files will be
|
|
ignored entirely).
|
|
|
|
Note that a similar effect to file immutability can be achieved by using file
|
|
system permissions to prevent the user from writing to their local versions of
|
|
the configuration file, although (since this is normally a setup error), the
|
|
user will be warned that the configuration file is not writable. This warning
|
|
can be suppressed by adding the following setting to either the relevant
|
|
configuration file or the `kdeglobals` file:
|
|
|
|
[General]
|
|
warn_unwritable_config=true
|
|
|
|
However, using file system permissions like this can potentially be circumvented
|
|
by the user if they have write access to the containing directory or can modify
|
|
environment variables (and `XDG_CONFIG_HOME` in particular).
|
|
|
|
|
|
|
|
Shell Expansion
|
|
---------------
|
|
|
|
If an entry is marked with `$e`, environment variables will be expanded.
|
|
|
|
Name[$e]=$USER
|
|
|
|
When the "Name" entry is read `$USER` will be replaced with the value of the
|
|
`$USER` environment variable.
|
|
|
|
Note that the application will replace `$USER` with its
|
|
expanded value after saving. To prevent this combine the `$e` option
|
|
with `$i` (immmutable) option. For example:
|
|
|
|
Name[$ei]=$USER
|
|
|
|
This will make that the "Name" entry will always return the value of the `$USER`
|
|
environment variable. The user will not be able to change this entry.
|
|
|
|
The following syntax for environment variables is also supported:
|
|
|
|
Name[$ei]=${USER}
|
|
|
|
There are three environment variables that have a fallback strategy if the
|
|
environment variable is not set. They instead map to a location from QStandardPaths.
|
|
They are:
|
|
|
|
* `$QT_CACHE_HOME` - QStandardPaths::GenericCacheLocation
|
|
* `$QT_CONFIG_HOME` - QStandardPaths::GenericConfigLocation
|
|
* `$QT_DATA_HOME` - QStandardPaths::GenericDataLocation
|