flowhdl-msg.c

通过消息队列让几个进程间支持通信

#include <unistd.h>
#include <fcntl.h>		// for O_RDWR,O_RDONLY,o_WRONLY
#include <sys/types.h>
#include <sys/msg.h>

#define JDEBUG
#include "jdebug.h"
#include "msghdr.h"
#define DSPFILE "/dev/dspHPI"

/* define buffer length */
#define	NLEN	2048
#define GLEN	2048
//#define DLEN (NLEN > GLEN?NLEN:GLEN)
#define DLEN	NLEN 
//extern int state;
int openfifo(char *file,mode_t mode)
{
	int retv;
	retv = open(file, mode);
	if (retv < 0)
	{
		printf("cant open fifo:%s\n",file);
		exit(0);
	}
	return retv;
}

int creatqueue(key_t key)
{
	int retv;
	retv = msgget(key, IPC_CREAT|0666);
	if (retv < 0)
	{
		printf("can not create queue:%d\n",key);
		exit(0);
	}
	return retv;
}
/* do packeting operation for arm<->dsp interface 
	if the packet format changes, here should be modified too.
*/
void packet(char *buf, int *length, int type)
{
/*  0   2    4     5
	|len|type|octet|...data...|pad|
	at least should add 5 octets
	if data_len is odd, add 5 octets, then become even
	if data_len is even, add 5 octets, then odd, should pad 1 octet

	consideration that dsp can just handle 16bit-based
*/
	int len = *length;
	if (len%2)	/* odd */
	{
		len += 1;
		buf[4] = 1;
		/* do padding at the end */
		buf[len-1] = 0; 
	}
	else
	{
		buf[4] = 0;
		/* no padding needed*/
	}
	
	buf[0] = len & 0xff;
	buf[1] = (len>>8) & 0xff;
	buf[2] = type & 0xff;
	buf[3] = (type>>8) & 0xff;
	
	*length = len;
	return;
}

int main()
{
	int qdni,qdno;
	int qdgi,qdgo;
	int fddsp;
	msg_t nimsg,gimsg;
	msg_t omsg;
	char dspbuf[DLEN];
	
	int nilen,nolen,gilen,golen;
	int dsplen, tmp, datalen,datatype;
	int retv;
/*	
	fdni = openfifo(NICINCOME,O_RDONLY); 
	fdno = openfifo(NICOUTPUT,O_WRONLY);
	fdgi = openfifo(GUIINCOME,O_RDONLY);
	fdgo = openfifo(GUIOUTPUT,O_WRONLY);
*/
	qdni = creatqueue(NICIKEY);	
	qdno = creatqueue(NICOKEY);	
	qdgi = creatqueue(GUIIKEY);	
	qdgo = creatqueue(GUIOKEY);	
	fddsp = open(DSPFILE,O_RDWR);
	if (fddsp < 0)
	{
		printf("cant open %s,pls check it. stop\n",DSPFILE);
		exit(0);
	}
	Jdebug("flowhdl:creat 4 msg queues and dsp finished!\n");
	
	/* Xibuf[0-1] reserved for length */
	/* Xibuf[2-3] reserved for types */
	/* Xibuf[4]   indicates pad or not */
	/* type=0x1111 for nic data(web service)
	   type=0x2222 for gui data(qt interface)
	   type=0x3333 for reconfig data(dsp reconfig)
	*/
	if (fork() == 0)	// child process, read dsp and write Xoutput fifo
	{
		Jdebug("flowhdl chd1: r dsp and w OUT msg queues\n");
		while(1)
		{
			dsplen = read(fddsp, dspbuf, DLEN);
			//Jdebug("flowhdl chd1: read dsp return %d\n",dsplen);
			if (dsplen)	// read dsp valid
			{
				datalen = dspbuf[0] + (dspbuf[1] << 8);
				if (dsplen != datalen)
					{	
						printf("dsplen != tmp. oddy!still continue,!!!dsplen-datalen=!!!%d\n",dsplen-datalen);
						continue;
					}
				datatype = dspbuf[2] + (dspbuf[3] << 8);
				if (dspbuf[4])	/* dspbuf[4]==1 pading */
					dsplen -= 1;
				memcpy(omsg.data, dspbuf, dsplen);
				//printf("!!!!!!state=%d!!!!!!!\n",state);
				switch(datatype)
				{
					case 0x1111: /* to nic */
					//	tmp = write(fdno, dspbuf+5, dsplen);
						omsg.type = 0x1111;
						retv = msgsnd(qdno, &omsg,dsplen+LONGSIZE,IPC_NOWAIT);
						if (!retv)
						Jdebug("flowhdl chd1:write NicOut Queue %d\n",dsplen+LONGSIZE);
						else
						Jdebug("####flowhdl chd1: write NicOUT queue failed\n");
						break;
					case 0x2222: /* to gui */
						omsg.type = 0x2222;
						msgsnd(qdgo, &omsg, dsplen+LONGSIZE,0);
						break;
					case 0x3333: /* reconfig return,to gui? */
						omsg.type = 0x3333;
						msgsnd(qdgo, &omsg, dsplen+LONGSIZE,0);
						break;
					default:
						printf("data type undefined!drop data\n");
						break;
				}
				
			}
		}
	}
	else
	{ 
	/* creat process or thread to read each incoming fifo */
		if (fork() == 0)	//another child process,read nic incoming data
		{	
			Jdebug("flowhdl child2: r nic and w dsp\n");
			while(1)
			{
				nilen = msgrcv(qdni, &nimsg, NLEN, 0,0);
				Jdebug("flowhdl child2: read NicInQueue %d\n",nilen);
				if (nilen > 0)		/* read valid */
				{
					nilen = nilen - LONGSIZE;
					/* nimsg len is including length+type+flag */
					packet(nimsg.data, &nilen, 0x1111);
					tmp = write(fddsp, nimsg.data, nilen);
					Jdebug("flowhdl child2:write dsp return %d\n",tmp);
				}		
			}
		}
		else
		{
			Jdebug("flowhdl parent: r gui and w dsp\n");
			while(1)		//parent read gui incoming data
			{
				gilen = msgrcv(qdgi, &gimsg, GLEN,0,0);
				Jdebug("flowhdl parent: read GuiIncome %d\n",gilen);
				if (gilen > 0)
				{
					gilen -= LONGSIZE;
					packet(gimsg.data, &gilen, 0x2222);
					tmp = write(fddsp, gimsg.data, gilen);
					Jdebug("flowhdl parent:write dsp return %d\n",tmp);
				}
			}
		}
	}
	
	msgctl(qdni,IPC_RMID, 0);
	msgctl(qdno,IPC_RMID, 0);
	msgctl(qdgi,IPC_RMID, 0);
	msgctl(qdgo,IPC_RMID, 0);
	close(fddsp);
}