example10_1.c

LinuxNetProgramming Linux网络编程基础实例

/* example10_1.c */
#include <stdio.h>
#include <sys/types.h> 
#include <sys/socket.h> 
#include <sys/un.h>
#include <string.h>
#include <stdlib.h>
#include <sys/time.h>
#define SOCKETNAME  "/faculty/rossa/system/mysocket"

int
main(void){
	char buf[1024];			/* Buffer for messages to others. */
	int s;					/* Listen socket */	
int ns;					/* Socket for first connection. */
	int ns2;					/* Socket for second connection. */
	int len;					/* len of sockaddr */	
	int maxfd;				/* descriptors up to maxfd-1 polled*/
	int nread;				/* # chars on read()*/	
int nready;				/* # descriptors ready. */
	struct sockaddr_un name;	
fd_set fds;				/* Set of file descriptors to poll*/
		/* Remove any previous socket.*/	
unlink(SOCKETNAME);	
/* Create the socket. */
	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)	{	
perror("socket");	
exit(1);
    }	
/* Create the address of the server.*/
	memset(&name, 0, sizeof(struct sockaddr_un));	
name.sun_family = AF_UNIX;
	strcpy(name.sun_path, SOCKETNAME);
	len = sizeof(name.sun_family) + strlen(name.sun_path);
		/*Bind the socket to the address.*/
	if (bind(s, (struct sockaddr *) &name, len) < 0) {	
perror("bind");
exit(1);
}
		/* Listen for connections. */	
if (listen(s, 5) < 0){	
perror( "listen");
		exit(1);	
}        
/*Accept a connection.*/
	if ((ns = accept(s, (struct sockaddr *) &name, &len)) < 0) {	
perror("accept");
		exit(1);	
}	
/* Accept another connection. */
	if ((ns2 = accept(s, (struct sockaddr *) &name, &len)) < 0) {	
perror("accept");
		exit(1);	
}		
maxfd = (ns > ns2 ? ns : ns2) + 1;
while(1){
			/* Set up polling using select. */
FD_ZERO(&fds);
		FD_SET(ns,&fds);
		FD_SET(ns2,&fds);
/* Wait for some input. */
nready = select(maxfd, &fds, (fd_set *) 0, (fd_set *) 0, (struct timeval *) 0);
		/* If either descriptor has some input, 
read it and copy it to the other. */
if( FD_ISSET(ns, &fds))	 {
			nread = recv(ns, buf, sizeof(buf), 0);
/* If error or eof, terminate. */
			if(nread < 1){	
close(ns);
close(ns2);
exit(0);
}
			send( ns2, buf, nread, 0);
		}
		if( FD_ISSET(ns2, &fds)) {
			nread = recv(ns2, buf, sizeof(buf), 0);
				/* If error or eof, terminate. */
			if(nread < 1) {
				close(ns);	
				close(ns2);
				exit(0);
			}
			send( ns, buf, nread, 0);
		}
}
}