source: rtems/doc/networking/servers.t @ f3482e3

@c
@c  Text Written by Jake Janovetz
@c
@c  COPYRIGHT (c) 1988-1998.
@c  On-Line Applications Research Corporation (OAR).
@c  All rights reserved.
@c
@c  $Id$
@c


@chapter Network Servers

@section RTEMS FTP Daemon

The RTEMS FTPD is a complete file transfer protocol (FTP) daemon
which can store, retrieve, and manipulate files on the local 
filesystem.  In addition, the RTEMS FTPD provides ``hooks'' 
which are actions performed on received data.  Hooks are useful
in situations where a destination file is not necessarily
appropriate or in cases when a formal device driver has not yet
been implemented.

This server was implemented and documented by Jake Janovetz
(janovetz@@tempest.ece.uiuc.edu).

@subsection Configuration Parameters

The configuration structure for FTPD is as follows:

@example
struct rtems_ftpd_configuration
@{
   rtems_task_priority     priority;           /* FTPD task priority  */
   unsigned long           max_hook_filesize;  /* Maximum buffersize  */
                                               /*    for hooks        */
   int                     port;               /* Well-known port     */
   struct rtems_ftpd_hook  *hooks;             /* List of hooks       */
@};
@end example

The FTPD task priority is specified with @code{priority}.  Because
hooks are not saved as files, the received data is placed in an
allocated buffer.  @code{max_hook_filesize} specifies the maximum
size of this buffer.  Finally, @code{hooks} is a pointer to the 
configured hooks structure.

@subsection Initializing FTPD (Starting the daemon)

Starting FTPD is done with a call to @code{rtems_initialize_ftpd()}.
The configuration structure must be provided in the application 
source code.  Example hooks structure and configuration structure
folllow.

@example
struct rtems_ftpd_hook ftp_hooks[] =
   @{
      @{"untar", Untar_FromMemory@},
      @{NULL, NULL@}
   @};

struct rtems_ftpd_configuration rtems_ftpd_configuration =
   @{
      40,                     /* FTPD task priority */
      512*1024,               /* Maximum hook 'file' size */
      0,                      /* Use default port */
      ftp_hooks               /* Local ftp hooks */
   @};
@end example

Specifying 0 for the well-known port causes FTPD to use the
UNIX standard FTPD port (21).

@subsection Using Hooks

In the example above, one hook was installed.  The hook causes
FTPD to call the function @code{Untar_FromMemory} when the 
user sends data to the file @code{untar}.  The prototype for
the @code{untar} hook (and hooks, in general) is:

@example
   int Untar_FromMemory(unsigned char *tar_buf, unsigned long size);
@end example

An example FTP transcript which exercises this hook is:

@example
220 RTEMS FTP server (Version 1.0-JWJ) ready.
Name (dcomm0:janovetz): John Galt
230 User logged in.
Remote system type is RTEMS.
ftp> bin
200 Type set to I.
ftp> dir 
200 PORT command successful.
150 ASCII data connection for LIST.
drwxrwx--x      0     0         268  dev
drwxrwx--x      0     0           0  TFTP
226 Transfer complete.
ftp> put html.tar untar
local: html.tar remote: untar
200 PORT command successful.
150 BINARY data connection.
210 File transferred successfully.
471040 bytes sent in 0.48 secs (9.6e+02 Kbytes/sec)
ftp> dir
200 PORT command successful.
150 ASCII data connection for LIST.
drwxrwx--x      0     0         268  dev
drwxrwx--x      0     0           0  TFTP
drwxrwx--x      0     0        3484  public_html
226 Transfer complete.
ftp> quit     
221 Goodbye.
@end example