source: rtems/cpukit/librpc/src/rpc/rtime.c @ 5220ae2

/*
 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
 * unrestricted use provided that this legend is included on all tape
 * media and as a part of the software program in whole or part.  Users
 * may copy or modify Sun RPC without charge, but are not authorized
 * to license or distribute it to anyone else except as part of a product or
 * program developed by the user.
 * 
 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 * 
 * Sun RPC is provided with no support and without any obligation on the
 * part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 * 
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
 * OR ANY PART THEREOF.
 * 
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 * 
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */

/*
 * Copyright (c) 1988 by Sun Microsystems, Inc.

 */

/*
 * 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 <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <stdio.h>
#include <netdb.h>
#include <sys/select.h>

#if defined(LIBC_SCCS) && !defined(lint)
/* from: static char sccsid[] =         "@(#)rtime.c    2.2 88/08/10 4.0 RPCSRC; from 1.8 88/02/08 SMI"; */
static const char rcsid[] = "$FreeBSD: src/lib/libc/rpc/rtime.c,v 1.5 2000/01/27 23:06:41 jasone Exp $";
#endif

extern int _rpc_dtablesize __P(( void ));

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

static void do_close __P(( int ));

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

        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;

        /* TCP and UDP port are the same in this case */
        if ((serv = getservbyname("time", "tcp")) == NULL) {
                return(-1);
        }

        addrp->sin_port = serv->s_port;

        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_dtablesize(), &readfds,
                                     (fd_set *)NULL, (fd_set *)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 = _RPC_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);
        timep->tv_sec = thetime - TOFFSET;
        timep->tv_usec = 0;
        return(0);
}

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

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