Subversion Repositories openrisc_2011-10-31

USING RPC/XDR ON RTEMS
======================
For the most part, programmers using RPC/XDR routines on RTEMS
can proceed as if they were to be using a POSIX/UNIX system.
The only significant changes are those to start the portmapper
and to allow use of RPC/XDR by multiple threads.

Starting the portmapper
=======================
The SUN portmapper program has been modified to run as an RTEMS
task.  Applications which need the portmapper can start this
task by calling:
        int rtems_rpc_start_portmapper (int priority);
The return value is an RTEMS status code.

Multi-threaded operation
========================
The RPC/XDR package has been modified to allow for multiple RTEMS
tasks to use RPC/XDR routines.  If more than one task is to call
an RPC/XDR routine, the additional tasks must call:
        int rtems_rpc_task_init(void);
before calling any RPC/XDR routines.  For example, the portmapper
calls this routine since the portmapper uses RPC/XDR routines in
a separate thread.
The return value is an RTEMS status code.


Porting Notes
=============
Most of the FreeBSD rpc library ports to RTEMS with little
or no modification beyond that required to provide for operation
in a multitasking environment.  Multitasking operation was
provided by moving all `static persistence' variables into
a single structure and using an RTEMS task variable to point
to that structure.  

Some of the library, however, has not made it into the RTEMS
implementation.  FreeBSD source files which have been left out include:
- Files which provide RPC to the AF_UNIX address family:
        clnt_unix.c
        svc_unix.c
  An `ifndef __rtems__' was added to clnt_generic.c because clnt_unix.c
  was omitted.
- Files which need NIS:
        auth_time.c
- Files which provide DES authentication:
        auth_des.c
        authdes_prot.c
        crypt_client.c
        des_crypt.c
        des_soft.c
        getpublickey.c
        key_call.c
        key_prot_xdr.c
        svc_auth_des.c

The FreeBSD xdr source compiles and runs on RTEMS without modification.

The original source was obtained from:
        ftp://ftp.FreeBSD.org/pub/FreeBSD/
                        branches/4.0-stable/src/lib/libc/rpc
                        branches/4.0-stable/src/lib/libc/xdr
                        branches/4.0-stable/src/include/rpc
                        branches/4.0-stable/src/include/rpcsvc