/* server for inet stream demo */
/* cmd format: istr <receive-sockect-name> */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>

#define TRUE 1
#define MAXLINE 256

/* this program creates a socket and then begin an infinite loop.  Each time
 * through the loop, it accepts a connection, prints out messages from it,
 * and then ask for reply message from the user.
 * When the connection breaks, or a termination messgage come through, the
 * program accepts a new connection. 
 */

getline(s, lim)
char s[];
int lim;
{
        int c, i;

        for (i=0; i<lim-1 && (c=getchar()) != EOF && c != '\n' ; ++i)
                s[i] = c;
        if (c == '\n') {
                s[i]= c;
                i++;
        }
        s[i]= '\0';
        return(i);
}

main()
{
	int sock;
	int length;
	struct sockaddr_in server;
	int msgsock;
	char buf[1024];
	char fromBuf[1024];
	int rval;
	int i;

	/* create socket from which to read */
	sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock < 0) {
		perror("opening stream socket");
		exit(1);
	}
	/* create name structure with wildcard using INADDR_ANY */

	server.sin_family = AF_INET;
	server.sin_addr.s_addr = INADDR_ANY;
	server.sin_port = 0;  

	/* port no. < 1024 IPPORT_RESERVED is for privillege process */
	/* here just initialized it, it will be assigned value after call */
	/* getsockname() */

	if (bind(sock, &server, sizeof(server))) {
		perror("binding server to datagram socket");
		exit(1);
	}
	/* Find assigned port value and print out. */
	printf("before getsockname socket has port #%d\n", ntohs(server.sin_port));
	length = sizeof(server);
	if (getsockname(sock, &server, &length)) {
		perror("getting socket name");
		exit(1);
	}
	printf("socket has port #%d\n", ntohs(server.sin_port));

	/* start accepting connections */
	listen(sock, 1);
	do {
		msgsock = accept(sock, 0, 0);
		if (msgsock == -1)
			perror("accept");
		else do {
			bzero(buf, sizeof(buf));
			if ((rval = read(msgsock, buf, 1024)) < 0)
				perror("reading stream message");
			i = 0;
			if (rval == 0) {
				printf("Ending connection\n");
				break;
			} else
				printf("rcvd msg-->%s\n", buf);
			printf("What is your reply (\"$\" to break connection)?");
			if ((rval=getline(fromBuf, 1024)) <= 0) 
				break; 
			if (fromBuf[0] == '$') {
				rval = 0;
				break;
			}
			/* send back reply */
			if (write(msgsock, fromBuf, strlen(fromBuf)) < 0)
				perror("writing on stream socket");
		} 
		while (rval != 0);
		close(msgsock);
	} 
	while (TRUE);
}