pipeserver.c

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/* pipeServer.c - reads requests over pipe */

#include "vxWorks.h"
#include "pipeDrv.h"
#include "taskLib.h"
#include "ioLib.h"


typedef struct
	{
	VOIDFUNCPTR routine;
	int arg;
	} MSG_REQUEST;


#define TASK_PRI						254		 /* server priority */
#define TASK_STACK 20000  /* server stack space */
#define PIPE_NAME						"/pipe/server"
#define NUM_MSGS						10

int pipeFd;

LOCAL void pipeServer ();

/**************************************************
* serverStart -- Initializes a server task to
* execute functons at a low priority. Uses pipes as
* the communication mechanism.
*
* RETURNS: OK or ERROR on failure.
*/

STATUS serverStart (void)
	{

	/* Create the pipe device */

	if (pipeDevCreate (PIPE_NAME, NUM_MSGS, 
			sizeof (MSG_REQUEST)) == ERROR)
		return (ERROR);
	
	/* Open the pipe */

	if ((pipeFd = open (PIPE_NAME, UPDATE, 0))
			== ERROR)
		return (ERROR);
	
	/* Spawn the server task */

	if (taskSpawn ("tServer", TASK_PRI, 0,
						TASK_STACK, (FUNCPTR)pipeServer,
						0,0,0,0,0,0,0,0,0,0) == ERROR)
		{
		close (pipeFd);
		return (ERROR);
		}
	
	return (OK);
	}

/**************************************************
* serverSend -- Sends a request to the server to
* execute a function at the server's priority.
*
* RETURNS: OK or ERROR on failure.
*/

STATUS serverSend 
	(
	VOIDFUNCPTR routine,
	int arg
	)
	{
	MSG_REQUEST msgRequest;
	int status;

	/* Initialize the message structure */

	msgRequest.routine = routine;
	msgRequest.arg = arg;

	/* Send the message and return the results */

	status = write (pipeFd, (char *)&msgRequest,
						sizeof (MSG_REQUEST));

	return ((status == sizeof (MSG_REQUEST)) ?
				OK : ERROR);
	}

/**************************************************
* pipeServer -- Server task which reads from a pipe
* and executes the function passed in the
* MSG_REQUEST data structure.
*
*/

LOCAL void pipeServer (void)
	{
	MSG_REQUEST msgRequest;

	while (read (pipeFd, (char *)&msgRequest, 
					 sizeof (MSG_REQUEST)) > 0)
		(*msgRequest.routine) (msgRequest.arg);
	}