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Chapter 1. Configuration Overview: The GConf System

Tip

Readers might first wish to refer to the GConf section of the GNOME Desktop System

Administration Guide available through Applications (the main menu on the panel) => Help, and

by selecting the Desktop Category, selecting the System Administration Guide Document, and

reading the chapter titled Using GConf , and also the GConf project page located on the web at

http://www.gnome.org/projects/gconf/ before continuing. Specifically, the use of gconftool 2 to

load and dump preference settings is not discussed in depth in this document, but is detailed in the

GNOME Guide.

GConf stores preferences data in a set of configuration sources. The sources used, their properties,

and the order in which they are used by GConf is defined in the

/etc/gconf/2/path

file.

Each configuration source entry has three parts:

Storage Backend Identifier

The only commonly used configuration backend is the XML backend whose identifier is

xml

.

Configuration Source Flags

A comma separated list of flags which is interpreted by the storage backend. The XML backend

recognizes two flags  

readonly

and

readwrite

which determine whether the configuration

source is writable.

Storage Location

The location in which the storage backend should store the preferences data. The exact meaning

of this storage location depends on the storage backend in use. With the XML backend, the

location is the path to a filesystem directory.

By default there is a Mandatory Source, a User Source and a Defaults Source. They are:

xml:readonly:/etc/gconf/gconf.xml.mandatory

xml:readwrite:$(HOME)/.gconf

xml:readonly:/etc/gconf/gconf.xml.defaults

The order of the configuration sources is intentional. If a key is set in the Mandatory Source and the

Defaults Source, then the value in the Mandatory Source takes precedence. Therefore, by setting the

value of a key in the Mandatory Source, users will not be able to modify that key.

The default GConf path file also includes a number of other path files if they exist. The

/etc/gconf/2/path

file allows administrators to define new configuration sources and include

them in the set of configuration sources used by GConf. The configuration sources specified in the

path

file are included before the standard Defaults Source.

One final item of note is that the storage location specifier for a source may also reference

the value of environmental variables. For example, the standard User Source is defined as

xml:readwrite:$(HOME)/.gconf

. Environmental variables may be defined as follows:

$(HOME)

The user's home directory.

$(USER)

The user's username.