#include <stdio.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

main(int argc,char ** argv)
{
	int s;
	struct sockaddr_un sockaddr;
	char line[128];
	char reply[128];
	int socket_errno;
	int i, err;
	int flags;
	fd_set read_set, read_cur;
	int max_fd;
	int ret;
	struct  iovec vec;
	struct  msghdr msghdr;
	int	client_fd;
	struct  cmsghdr *cmsg;
	int	*pass_fd_ptr;
	char	cmsgbuf[CMSG_SPACE(sizeof (int))];
	
	if ((s=socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
		socket_errno = errno;
		fprintf(stdout,"can't create socket [%d]\n",socket_errno);
		exit(-1);
	}
	
	unlink("/tmp/unix_d_test");
	memset(&sockaddr, '\0', sizeof(sockaddr));
	sockaddr.sun_family      = AF_UNIX;
	strcpy(sockaddr.sun_path, "/tmp/unix_d_test");
	
	if (bind(s,(struct sockaddr *)&sockaddr, sizeof(sockaddr)) < 0) {
		socket_errno = errno;
		fprintf(stdout,"can't bind socket [%d]\n",errno);
		exit(-1);
	}
	
	if (listen(s, 10) < 0) {
		fprintf(stdout, "listen() error %d\n", socket_errno);
		exit(-1);
	}

	FD_ZERO(&read_set);
	FD_SET(s, &read_set);
	max_fd = s;
	client_fd = -1;

	for(;;) {
		for(i = 0 ; i < 128 ; i++) {
			line[i] = 0;
		}
		
		read_cur = read_set;
		ret = select(max_fd+1, &read_cur, NULL, NULL, NULL);
		if (ret == -1) {
			fprintf(stdout, "select() error %d\n", errno);
			continue;
		}
		for (i = 0; i <= max_fd; i++) {
			if (FD_ISSET(i, &read_cur)) {
				if (i == s) {
					struct sockaddr_un    address;
					int	len;

					if (client_fd != -1) {
						close(client_fd);
					}

					len = sizeof(struct sockaddr_un);
					client_fd = accept(s, (struct sockaddr *)&address, &len);
					if (client_fd == -1) {
						fprintf(stdout, "accept() error %d\n", errno);
						exit(-1);
					}
					if ( client_fd > max_fd ) max_fd = client_fd;
				} else if (i == client_fd) {
					fprintf(stdout, "read from client_fd\n");
				}
				
				msghdr.msg_name    = NULL;
				msghdr.msg_namelen = 0;
				msghdr.msg_iov     = &vec;
				msghdr.msg_iovlen  = 1;
				msghdr.msg_control    = cmsgbuf;
				msghdr.msg_controllen = sizeof(cmsgbuf);
				vec.iov_base  = line;
				vec.iov_len   = 128;
				if ((ret = recvmsg(client_fd, &msghdr, 0)) < 128) {
					fprintf(stdout, "recvmsg() error %d\n", errno);
					exit(-1);
				}
				for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg != NULL; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {
					if (cmsg->cmsg_level == SOL_SOCKET) {
						pass_fd_ptr = (int *)CMSG_DATA(cmsg);
						break;
					}
				}
				fprintf(stdout, "recvmsg() is done.\n");
				close(*pass_fd_ptr);

				msghdr.msg_name    = NULL;
				msghdr.msg_namelen = 0;
				msghdr.msg_iov     = &vec;
				msghdr.msg_iovlen  = 1;
				msghdr.msg_controllen = 0;
				msghdr.msg_control    = NULL;
				vec.iov_base  = reply;
				vec.iov_len   = 128;
				if ((ret = sendmsg(client_fd, &msghdr, 0 )) < 128) {
					fprintf(stdout, "sendmsg error %d\n", errno);
					exit(-1);
				}
				fprintf(stdout, "sendmsg() %d byte OK. \n", ret);
				
				FD_ZERO(&read_set);
				FD_SET(s, &read_set);
				break;
			}
		}
		
	}
	fprintf(stdout,"GOOD BY \n");
	exit (0);
}