#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>

#define SOCK_PATH 	"/tmp/echo_socket"
#define BUF_SIZE	1024

int main(void)
{
	int s, s2;
	socklen_t len;
	socklen_t t;
	struct sockaddr_un local, remote;
	char str[BUF_SIZE];

	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
		perror("socket");
		exit(1);
	}

	local.sun_family = AF_UNIX;
	strcpy(local.sun_path, SOCK_PATH);
	unlink(local.sun_path);
	len = strlen(local.sun_path) + sizeof(local.sun_family);
	if (bind(s, (struct sockaddr *)&local, len) == -1) {
		perror("bind");
		exit(1);
	}

	if (listen(s, 5) == -1) {
		perror("listen");
		exit(1);
	}

	while(1) {
		int done, n;
		printf("Waiting for a connection...\n");
		t = sizeof(remote);
		if ((s2 = accept(s, (struct sockaddr *)&remote, &t)) == -1) {
			perror("accept");
			exit(1);
		}

		printf("Connected.\n");

		done = 0;
		do {
			n = recv(s2, str, BUF_SIZE, 0);
			if (n <= 0) {
				if (n < 0) perror("recv");
				done = 1;
			}

			if (!done) 
				if (send(s2, str, n, 0) < 0) {
					perror("send");
					done = 1;
				}
		} while (!done);

		close(s2);
	}

	return 0;
}