A profile file is a generic way of storing program configuration

information for applications.  An application may choose to consult

multiple configuration files; for example, a Kerberos application

might look first in ~/.krb5rc, and then in /etc/krb5.conf.  So

/etc/krb5.conf would contain the side-wide default configuration for

Kerberos, and ~/.krb5rc would contain the user's specific

configuration overrides.

Configuration information is stored in relations, which have a name

and a value.  There may be multiple relations with the same name.

Relations are always contained inside named sections.  Sections can

contain relations and other named child sections.

Top-level sections are defined by enclosing the section name in square

braces.  Child sections are defined by enclosing the contents of the

child section in curly braces.  Relations are defined by using the

format "name = value".  

An example profile file might look like this:

[libdefaults]

	default_realm = ATHENA.MIT.EDU

[realms]

	ATHENA.MIT.EDU = {

		kdc = kerberos.mit.edu

		kdc = kerberos-1.mit.edu

		kdc = kerberos-2.mit.edu

		master_kdc = kerberos.mit.edu

		admin_server = kerberos.mit.edu

	}

	CYGNUS.COM = {

		kdc = KERBEROS-1.CYGNUS.COM

		kdc = KERBEROS.CYGNUS.COM

		admin_server = KERBEROS.MIT.EDU

	}

In this example, the profile file has two top-level sections,

"libdefaults" and "realms".  The libdefaults section has a single

relation which is named "default_realm" and has the value

"ATHENA.MIT.EDU".  The realms section has two child sections,

"ATHENA.MIT.EDU" and "CYGNUS.MIT.EDU".  Each of these child has a

number of relations, "kdc", "admin_server", and (in the case of

"ATHENA.MIT.EDU"), "default_domain".  Note that there are multiple

relations with the name "kdc" in both sections; if a

profile_get_values() is called querying the "kdc" relation, both

values will be returned.

Sections may be marked as "final".  If they are marked as final, then

the contents of that section override all subsequent profile files (if

the application is searching multiple profile files for its

configuration information).  Normally, all of the profiles are

searched for a matching relation, and all of the values found in all

of the various profile files will be returned.  

Top-level sections are marked as final by adding an '*' character

following the closing square brace.  Child sections are marked as

final by adding a '*' character after the closing curly brace.  So for

example, in this example both the "libdefaults" and "ATHENA.MIT.EDU"

sections have been marked as final:

[libdefaults]*

	default_realm = ATHENA.MIT.EDU

[realms]

	ATHENA.MIT.EDU = {

		kdc = kerberos.mit.edu

		master_kdc = kerberos.mit.edu

		admin_server = kerberos.mit.edu

	}*