OSF DCE Application Development Guide--Introduction and Style Guide

Security
This is done by calling the application’s registered resolver routine; the library finds the
right resolver routine by calling all the resolvers that have been registered with it until it
gets a successful return. It finds the ACL manager type in the same way, since it calls
each attempted resolver passing the manager type UUID that was registered with it. See
the sample_resolve_by_name() function in the sample_server.c file.
3.4.3.9 Backing Store Database Items and Headers
Note that although backing stores are necessary in implementing an ACL manager, their
use is not limited to ACL management. Backing stores are designed to be used for all
kinds of persistent storage of distibuted data. For more information, see the .
As mentioned earlier, backing store databases are necessary for storing any information
about the application’s objects that must be preserved between application server
sessions. The sample application uses three such databases, as described in Section
3.4.3.5.
From the point of view of the application that uses it, a database is characterized in the
following two ways:
• How it is indexed
• What kind of data item (record) can be stored in it
The former is specified by a flag passed to dce_db_open( ) when the database is first
created; the latter is determined by the declarations you make in an .idl file.
An example of defining a backing store database item can be seen in the sample_db.idl
and sample_db.acf files (note that the dce/database.idl file must be imported into the
.idl file). A server stub and a header file is generated from these files when the
application is compiled. The purpose of the .idl definitions is to establish the routine that
will handle the transmission of the data items across the wire. Note that we don’t
implement the conversion routine; we just declare it in the .idl file: IDL itself does the
rest, generating the necessary code in the client stub.
As has already been mentioned, the sample application uses three databases. The most
complex of these is the object-indexed store (its handle is db_object). The other two,
name-indexed (db_name) and ACL UUID-indexed (db_acl), are much simpler. Each of
the three is briefly described in the following sections.
3.4.3.10 Object-Indexed Store
The sample application maintains objects whose data consists of a simple text string;
however, the data type is also defined to contain a standard header. The standard header
is a structure defined in dce/database.idl. Mostly it contains fields for a set of UUIDs
that identify
• The object itself
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