OSF DCE Application Development Guide--Core Components

OSF DCE Application Development Guide—Core Components
Since the dced_binding_from_rpc_binding( ) routine already knows which host to bind
to from an RPC binding input parameter, it uses one of the global variables defined for
each service (instead of a string) to specify which dced service to use.
2.4.2 The dced Programs Maintains Entry Lists
One dced service’s data is very different from another’s (for example, server
configuration data versus key table data), but you manipulate the data in a similar way.
This is because it is a simpler and more efficient design to implement a few API routines
that can handle more than one kind of data rather than many routines that do essentially
the same thing but on a different service’s data. An added benefit is a flexible API that
can handle your own application’s data and new kinds of DCE data in the future.
To separate the actual data from the API implementation, a dced service maintains a list
of all data items in an entry list. Entry lists contain entries that describe the name and
location of each item of data, but they do not contain the actual data. With this
mechanism, dced can obtain and manipulate data very efficiently, without concern for
the implementation and location of the actual data. It also supports well the model that
administrators commonly need when accessing data: scan a list, select an item, and use
the data.
The dced program maintains entry lists for the hostdata, srvrconf, srvrexec, and keytab
services. The secval service does not need an entry list because it does not maintain any
data, but functions are performed to set its state.
There is a special relationship between srvrconf and srvrexec entries. In order for dced
to control the start of a server, the server must have a srvrconf entry associated with
server configuration data. When dced starts a server, it generates from the srvrconf entry
and data a srvrexec entry and associates the new entry with the running server’s state.
Figure 2-1 shows the entry lists maintained by dced.
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