/* receiver for unix domain datagram demo */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>

help_msg()
{
	printf("format: idgr\n");
}

main(argc, argv)
int argc;
char *argv[];
{
	int sock; 
	struct sockaddr_un to;
	struct sockaddr_un addr;
	int n, i;
	char toBuf[2048];
	char fromBuf[2048];
	int length;
	int flag = 1;

	/* create socket */
	sock = socket(AF_UNIX, SOCK_DGRAM, 0);
	if (sock < 0) {
		perror("opening datagram socket");
		exit(1);
	}
	addr.sun_family = AF_UNIX;
	sprintf(addr.sun_path, "/tmp/cs522.%s.server", getlogin());
	unlink(addr.sun_path); /* if previous incarnation of server still exists */
	if (bind(sock, &addr, sizeof(struct sockaddr_un))) {
		perror("binding name to datagram socket");
		exit(1);
	}
	/* ls -F /tmp  you will find a file with the same name there */
	printf("unix domain datagram server uses sun_path=%s\n", addr.sun_path);
	to.sun_family = AF_UNIX;
	/* sprintf(to.sun_path, "/tmp/cs522.%s.client", getlogin());*/

	/* receive message */
	while (flag) {
		n = recvfrom(sock, fromBuf, sizeof(fromBuf), 0, &to, &length);
		if (n < 0) perror("receiving datagram message");
		fromBuf[n] = 0; /* null terminate */
		printf("The no. of bytes received=%d\n", n);
		printf("lenght of to=%d\n", length);
		printf("sizeof(sun_path)=%d, sizeof(sun_family)=%d\n", 
			sizeof(to.sun_path), sizeof(to.sun_family));
		for (i=0; i<sizeof(to.sun_path); i++) {
			if ((i+1)%80 == 0) printf("\n");
			else printf("%c", to.sun_path[i]);
		}
		printf("\n");
		to.sun_path[length-sizeof(to.sun_family)] = '\0';
		printf("unix domain datagram client uses sun_path=%s\n", to.sun_path);
		printf("received msg=");
		sprintf(toBuf, "received message: %s\n", fromBuf);
		if (sendto(sock, toBuf, strlen(toBuf), 0, &to, length) < 0) 
			perror("sending datagram message");
	}
	unlink(addr.sun_path); /* clean up by removing the socket file descriptor */
	close(sock);
}