#include <stdio.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <signal.h>

#define SOCKNAME "sock_unix"

int main()
{
	int fd;
	struct sockaddr_un sunx;
	pid_t pid;
	ssize_t len;
	char buf[BUFSIZ];
	
	memset(&sunx, 0, sizeof(sunx));
	sunx.sun_family = AF_UNIX;
	strncpy (sunx.sun_path, SOCKNAME, sizeof(sunx.sun_path) -1 );

	pid = fork();
	if (pid) {
		int fd1;
		fd = socket(AF_UNIX, SOCK_STREAM, 0);
		if (fd < 0) {
			perror("socket");
			goto end_server;
		}
		if (bind(fd, (struct sockaddr *)&sunx, sizeof(sunx)) < 0) {
			perror("bind");
			goto end_server;
		}
		if (listen(fd, 1) < 0) {
			perror("listen");
			goto end_server;
		}
		fd1 = accept(fd, 0, 0);
		if (fd1 < 0) {
			perror("accept");
			goto end_server;
		}
		while ((len = read(fd1, buf, sizeof(buf))) > 0) {
			buf[len] = '\0';
			printf("%d: %s\n", len, buf);
		}
		close(fd1);
end_server:
		close(fd);
		kill(pid, SIGTERM);
		wait(NULL);
		if (unlink(SOCKNAME) < 0) {
			perror("unlink");
		}
	} else {
		usleep(100000);
		fd = socket(AF_UNIX, SOCK_STREAM, 0);
		if (fd < 0) {
			perror("socket");
			goto end_client;
		}
		if (connect(fd, (struct sockaddr *)&sunx, sizeof(sunx)) < 0) {
			perror("connect");
			goto end_client;
		}
		write(fd, "1234567890", 10);
end_client:
		close(fd);
	}
	
	return 0;
}