/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*
 * rtime - get time from remote machine
 *
 * gets time, obtaining value from host
 * on the udp/time socket.  Since timeserver returns
 * with time of day in seconds since Jan 1, 1900,  must
 * subtract seconds before Jan 1, 1970 to get
 * what unix uses.
 */

#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <errno.h>
#include <netinet/in.h>
#include <malloc.h>

#define NYEARS  (1970 - 1900)
#define TOFFSET ((uint_t)60*60*24*(365*NYEARS + (NYEARS/4)))

extern int _socket(int, int, int);
extern int _sendto(int, const char *, int, int,
        const struct sockaddr *, int);
extern int _recvfrom(int, char *, int, int,
        struct sockaddr *, int *);
extern int _connect(int, struct sockaddr *, int);
extern int __rpc_dtbsize();
extern ssize_t read(int, void *, size_t);
extern int close(int);
static void do_close();

int
rtime(addrp, timep, timeout)
        struct sockaddr_in *addrp;
        struct timeval *timep;
        struct timeval *timeout;
{
        int s;
        fd_set readfds;
        int res;
        uint_t thetime;
        struct sockaddr_in from;
        int fromlen;
        int type;

        if (timeout == NULL) {
                type = SOCK_STREAM;
        } else {
                type = SOCK_DGRAM;
        }
        s = _socket(AF_INET, type, 0);
        if (s < 0) {
                return (-1);
        }
        addrp->sin_family = AF_INET;
        addrp->sin_port = htons(IPPORT_TIMESERVER);
        if (type == SOCK_DGRAM) {
                res = _sendto(s, (char *)&thetime, sizeof (thetime), 0,
                    (struct sockaddr *)addrp, sizeof (*addrp));
                if (res < 0) {
                        do_close(s);
                        return (-1);
                }
                do {
                        FD_ZERO(&readfds);
                        FD_SET(s, &readfds);
                        res = select(__rpc_dtbsize(), &readfds, NULL,
                            NULL, timeout);
                } while (res < 0 && errno == EINTR);
                if (res <= 0) {
                        if (res == 0) {
                                errno = ETIMEDOUT;
                        }
                        do_close(s);
                        return (-1);
                }
                fromlen = sizeof (from);
                res = _recvfrom(s, (char *)&thetime, sizeof (thetime), 0,
                    (struct sockaddr *)&from, &fromlen);
                do_close(s);
                if (res < 0) {
                        return (-1);
                }
        } else {
                if (_connect(s, (struct sockaddr *)addrp,
                        sizeof (*addrp)) < 0) {
                        do_close(s);
                        return (-1);
                }
                res = read(s, (char *)&thetime, sizeof (thetime));
                do_close(s);
                if (res < 0) {
                        return (-1);
                }
        }
        if (res != sizeof (thetime)) {
                errno = EIO;
                return (-1);
        }
        thetime = ntohl(thetime);

        thetime = thetime - TOFFSET;
#ifdef _ILP32
        if (thetime > INT32_MAX)
                thetime = INT32_MAX;
#endif
        timep->tv_sec = thetime;
        timep->tv_usec = 0;
        return (0);
}

static void
do_close(s)
        int s;
{
        int save;

        save = errno;
        (void) close(s);
        errno = save;
}