#include <modbus.h>#include <signal.h>int Mb_device;				/* device tu use */int Mbm_Pid_Child;		/* PID child used to read the slave answer */int Mbm_Pid_Sleep;		/* PID use to wait the end of the timeout */byte *Mbm_result;			/* byte readed on the serial port : answer of the slave *//************************************************************************************		Mbm_get_data : thread reading data on the serial port*************************************************************************************input :-------len	:	number of data to read;no output************************************************************************************/void Mbm_get_data(int *len ){   int i;   byte read_data;   Mbm_Pid_Child=getpid();      if (Mb_verbose)         fprintf(stderr,"starting receiving data, total length : %d \n",*len);   for(i=0;i<(*len);i++)   {      /* read data */      read(Mb_device,&read_data,1);      /* store data to the slave answer packet */      Mbm_result[i]=read_data;            /* call the pointer function if exist */      if(Mb_ptr_rcv_data!=NULL)         (*Mb_ptr_rcv_data)(read_data);      if (Mb_verbose)         fprintf(stderr,"receiving byte :0x%x %d (%d)\n",read_data,read_data,Mbm_result[i]);   }   if (Mb_verbose)      fprintf(stderr,"receiving data done\n");}/************************************************************************************		Mbm_sleep : thread wait timeout*************************************************************************************input :-------timeout : duduration of the timeout in msno output************************************************************************************/void Mbm_sleep(int *timeout){   Mbm_Pid_Sleep=getpid();	if (Mb_verbose)      fprintf(stderr,"sleeping %d ms\n",*timeout);   usleep(*timeout*1000);}/************************************************************************************		Mbm_send_and_get_result : send data, and wait the answer of the slave*************************************************************************************input :-------trame     : packet to sendtimeout   : duduration of the timeout in mslong_emit : length of the packet to sendlongueur  : length of the packet to readanswer :--------0         : timeout failure1         : answer ok************************************************************************************/int Mbm_send_and_get_result(byte trame[], int timeout, int long_emit, int longueur){   int i,stat1=-1,stat2=-1;	pthread_t thread1,thread2;   Mbm_result = (unsigned char *) malloc(longueur*sizeof(unsigned char));   /* clean port */   tcflush(Mb_device, TCIFLUSH);   /* create 2 threads for read data and to wait end of timeout*/   pthread_create(&thread2, NULL,(void*)&Mbm_sleep,&timeout);   pthread_create(&thread1, NULL,(void*)&Mbm_get_data,&longueur);	if (Mb_verbose)      fprintf(stderr,"start writing \n");   for(i=0;i<long_emit;i++)   {      /* send data */      write(Mb_device,&trame[i],1);      /* call pointer function if exist */      if(Mb_ptr_snd_data!=NULL)         (*Mb_ptr_snd_data)(trame[i]);   }  if (Mb_verbose)      fprintf(stderr,"write ok\n");   do {      if (Mbm_Pid_Child!=0)         /* kill return 0 if the pid is running or -1 if the pid don't exist */         stat1=kill(Mbm_Pid_Child,0);      else         stat1=0;      if (Mbm_Pid_Sleep!=0)         stat2=kill(Mbm_Pid_Sleep,0);      else         stat2=0;      /* answer of the slave terminate or and of the timeout */      if (stat1==-1 || stat2==-1)          break;   } while(1);    if (Mb_verbose)   {      fprintf(stderr,"pid reading %d return %d\n",Mbm_Pid_Child,stat1);      fprintf(stderr,"pid timeout %d return %d\n",Mbm_Pid_Sleep,stat2);   }   /* stop both childs */   Mbm_Pid_Child=0;   Mbm_Pid_Sleep=0;   pthread_cancel(thread1);   pthread_cancel(thread2);   /* error : timeout fealure */   if (stat1==0)   {      return 0;   }   /* ok : store the answer packet in the data trame */   for (i=0;i<=longueur;i++)      trame[i]=Mbm_result[i];   return 1;}      /************************************************************************************   				Mbm_master : comput and send a master packet*************************************************************************************input :-------Mb_trame	  : struct describing the packet to comput   					device		: device descriptor   					slave 		: slave number to call                  function 	: modbus function                  address		: address of the slave to read or write                  length		: lenght of data to senddata_in	  : data to send to the slavedata_out	  : data to read from the slavetimeout	  : timeout duration in msptrfoncsnd : function to call when master send data (can be NULL if you don't whant to use it)ptrfoncrcv : function to call when master receive data (can be NULL if you don't whant to use it)*************************************************************************************answer :--------0 : OK-1 : unknow modbus function-2 : CRC error in the slave answer-3 : timeout error-4 : answer come from an other slave*************************************************************************************/int Mb_master(Mbm_trame Mbtrame,int data_in[], int data_out[],void *ptrfoncsnd, void *ptrfoncrcv){   int i,longueur,long_emit;   int slave, function, adresse, nbre;   byte trame[256];   Mb_device=Mbtrame.device;   slave=Mbtrame.slave;   function=Mbtrame.function;   adresse=Mbtrame.address;   nbre=Mbtrame.length;   Mb_ptr_snd_data=ptrfoncsnd;   Mb_ptr_rcv_data=ptrfoncrcv;         switch (function)   {      case 0x03:      case 0x04:         /* read n byte */         trame[0]=slave;         trame[1]=function;         trame[2]=adresse>>8;         trame[3]=adresse&0xFF;         trame[4]=nbre>>8;         trame[5]=nbre&0xFF;         /* comput crc */         Mb_calcul_crc(trame,6);         /* comput length of the packet to send */         long_emit=8;         break;               case 0x06:         /* write one byte */         trame[0]=slave;         trame[1]=function;         trame[2]=adresse>>8;         trame[3]=adresse&0xFF;         trame[4]=data_in[0]>>8;         trame[5]=data_in[0]&0xFF;         /* comput crc */         Mb_calcul_crc(trame,6);         /* comput length of the packet to send */         long_emit=8;         break;      case 0x07:         /* read status */         trame[0]=slave;         trame[1]=function;         /* comput crc */         Mb_calcul_crc(trame,2);         /* comput length of the packet to send */         long_emit=4;         break;               case 0x08:         /* line test */         trame[0]=slave;         trame[1]=0x08;         trame[2]=0;         trame[3]=0;         trame[4]=0;         trame[5]=0;         Mb_calcul_crc(trame,6);         /* comput length of the packet to send */         long_emit=8;         break;               case 0x10:         /* write n byte  */         trame[0]=slave;         trame[1]=0x10;         trame[2]=adresse>>8;         trame[3]=adresse&0xFF;         trame[4]=nbre>>8;         trame[5]=nbre&0xFF;         trame[6]=nbre*2;         for (i=0;i<nbre;i++)         {            trame[7+i*2]=data_in[i]>>8;            trame[8+i*2]=data_in[i]&0xFF;         }         /* comput crc */         Mb_calcul_crc(trame,7+nbre*2);         /* comput length of the packet to send */         long_emit=(nbre*2)+9;         break;      default:         return -1;   }	if (Mb_verbose)    {   	fprintf(stderr,"send packet length %d\n",long_emit);      for(i=0;i<long_emit;i++)         fprintf(stderr,"send packet[%d] = %0x\n",i,trame[i]);   }      /* comput length of the slave answer */   switch (function)   {      case 0x03:      case 0x04:         longueur=5+(nbre*2);         break;            case 0x06:      case 0x08:      case 0x10:      longueur=8;         break;      case 0x07:      longueur=5;         break;      default:         return -1;         break;   }   /* send packet & read answer of the slave      answer is stored in trame[] */	if(!Mbm_send_and_get_result(trame,Mbtrame.timeout,long_emit,longueur))      return -3;	/* timeout error */  	if (Mb_verbose)   {      fprintf(stderr,"answer :\n");      for(i=0;i<longueur;i++)         fprintf(stderr,"answer packet[%d] = %0x\n",i,trame[i]);   }      if (trame[0]!=slave)      return -4;	/* this is not the right slave */   switch (function)   {      case 0x03:      case 0x04:         /* test received data */         if (trame[1]!=0x03 && trame[1]!=0x04)            return -2;         if (Mb_test_crc(trame,3+(nbre*2)))            return -2;         /* data are ok */         if (Mb_verbose)            fprintf(stderr,"Reader data \n");         for (i=0;i<nbre;i++)         {            data_out[i]=(trame[3+(i*2)]<<8)+trame[4+i*2];            if (Mb_verbose)               fprintf(stderr,"data %d = %0x\n",i,data_out[i]);         }         break;            case 0x06:         /* test received data */         if (trame[1]!=0x06)            return -2;         if (Mb_test_crc(trame,6))            return -2;         /* data are ok */         if (Mb_verbose)            fprintf(stderr,"data stored succesfull !\n");         break;      case 0x07:         /* test received data */         if (trame[1]!=0x07)            return -2;         if (Mb_test_crc(trame,3))            return -2;         /* data are ok */         data_out[0]=trame[2];	/* store status in data_out[0] */         if (Mb_verbose)            fprintf(stderr,"data  = %0x\n",data_out[0]);         break;      case 0x08:         /* test received data */         if (trame[1]!=0x08)            return -2;         if (Mb_test_crc(trame,6))            return -2;         /* data are ok */         if (Mb_verbose)            fprintf(stderr,"Loopback test ok \n");         break;      case 0x10:         /* test received data */         if (trame[1]!=0x10)            return -2;         if (Mb_test_crc(trame,6))            return -2;         /* data are ok */         if (Mb_verbose)            fprintf(stderr,"%d setpoint stored succesfull\n",(trame[4]<<8)+trame[5]);         break;      default:         return -1;         break;   }   return 0;}