sics/genbinprot.c

/*
 * genbinprot.c
 *
 * This is a generic binary protocol handler for scriptcontext. It expects a
 * command of the form:
 *
 *   writepointer:writecount:readpointer:readcount
 *
 * And will writecount bytes from the data area writepointer and
 * read readcount bytes into the memory area under readpointer.
 * If writecount  is 0, the nothing will be written. This can
 * be used to read a binary message in parts. Both writepointer and
 * readpointer are memory addresses in hexadecimal.
 *
 *  This is a workaround for the essential weakness of devser not being
 *  able to work with binary protocols.
 *
 *  Created on: Jul 7, 2010
 *      Author: koennecke
 */
#include <errno.h>
#include <stdio.h>
#include <sics.h>
#include <ascon.h>
#include <ascon.i>
#include <stptok.h>

/*-----------------------------------------------------------------*/
typedef struct {
	char *writePointer;
	unsigned int toWrite;
	char *readPointer;
	unsigned int readCount;
	unsigned int toRead;
}GenBin, *pGenBin;
/*------------------------------------------------------------------*/
static void initGenBin(Ascon *a)
{
	pGenBin self = (pGenBin)a->private;
	char *pPtr = NULL, pToken[60];
	long lval;

	pPtr = GetCharArray(a->wrBuffer);

	pPtr = stptok(pPtr,pToken,60,":");
	sscanf(pToken,"%lx",&lval);
	self->writePointer = (char *)lval;

	pPtr = stptok(pPtr,pToken,60,":");
	sscanf(pToken,"%d",&self->toWrite);

	pPtr = stptok(pPtr,pToken,60,":");
	sscanf(pToken,"%lx",&lval);
	self->readPointer = (char *)lval;

	pPtr = stptok(pPtr,pToken,60,":");
	sscanf(pToken,"%d",&self->toRead);

	a->wrPos = 0;
	self->readCount = 0;
}
/*------------------------------------------------------------------*/
static int GenBinHandler(Ascon *a)
{
	pGenBin self = (pGenBin)a->private;
	unsigned int toWrite;
	int ret;
	char chr;

	switch(a->state){
	case AsconWriteStart:
		AsconReadGarbage(a->fd);
		initGenBin(a);
		a->state = AsconWriting;
		break;
	case AsconWriting:
		toWrite = self->toWrite - a->wrPos;
		if(toWrite == 0){
			a->state = AsconWriteDone;
		} else {
			ret = AsconWriteChars(a->fd, self->writePointer+a->wrPos, toWrite);
			if (ret < 0) {
				if (errno != EINTR && errno != EAGAIN) {
					AsconError(a, "send failed:", errno);
				}
			} else {
				a->wrPos += ret;
				if(a->wrPos  >= self->toWrite){
					a->state = AsconWriteDone;
				}
			}
		}
		break;
	case AsconReading:
		if(self->readCount >= self->toRead){
			a->state = AsconReadDone;
			DynStringCopy(a->rdBuffer,"OK");
		} else {
			ret = AsconReadChar(a->fd, &chr);
		    if (ret < 0) {
		      /* EINTR means we must retry */
		      if (errno != EINTR && errno != EAGAIN) {
		        AsconError(a, "AsconReadChar failed:", errno);
		      }
		      return 1;
		    } else if (ret > 0) {
		      a->start = DoubleTime();
		      self->readPointer[self->readCount] = chr;
		      self->readCount++;
		    } else if (ret == 0) {
		      if (a->timeout > 0) {
		        if (DoubleTime() - a->start > a->timeout) {
		          AsconError(a, "read timeout", 0);
		          a->state = AsconTimeout;
		        }
		      }
		      return 0;
		    }
		}
		break;
	default:
		return AsconStdHandler(a);
	}
	return 1;
}
/*------------------------------------------------------------------------*/
static int GenBinInit(Ascon * a, SConnection * con, int argc, char *argv[])
{
  pGenBin priv = NULL;

  priv = calloc(sizeof(GenBin), 1);
  a->fd = -1;
  a->state = AsconConnectStart;
  a->reconnectInterval = 10;
  a->hostport = strdup(argv[1]);
  if (argc > 2) {
    a->timeout = atof(argv[2]);
  } else {
    a->timeout = 2.0;           /* sec */
  }
  a->private = priv;
  a->killPrivate = free;
  return 1;
}
/*------------------------------------------------------------------------*/
void AddGenBinProtocoll()
{
  AsconProtocol *prot = NULL;

  prot = calloc(sizeof(AsconProtocol), 1);
  prot->name = strdup("genbin");
  prot->init = GenBinInit;
  prot->handler = GenBinHandler;
  AsconInsertProtocol(prot);
}