sunrpc/rtime.c

   1 /*
   2  * Copyright (c) 2010, Oracle America, Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  *       notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  *       copyright notice, this list of conditions and the following
  12  *       disclaimer in the documentation and/or other materials
  13  *       provided with the distribution.
  14  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  15  *       contributors may be used to endorse or promote products derived
  16  *       from this software without specific prior written permission.
  17  *
  18  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  21  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  22  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  23  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  25  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  27  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31 /*
  32  * rtime - get time from remote machine
  33  *
  34  * gets time, obtaining value from host
  35  * on the udp/time socket.  Since timeserver returns
  36  * with time of day in seconds since Jan 1, 1900,  must
  37  * subtract seconds before Jan 1, 1970 to get
  38  * what unix uses.
  39  */
  40 #include <stdio.h>
  41 #include <unistd.h>
  42 #include <rpc/rpc.h>
  43 #include <rpc/clnt.h>
  44 #include <sys/types.h>
  45 #include <sys/poll.h>
  46 #include <sys/socket.h>
  47 #include <sys/time.h>
  48 #include <rpc/auth_des.h>
  49 #include <errno.h>
  50 #include <netinet/in.h>
  51
  52 #define NYEARS  (u_long)(1970 - 1900)
  53 #define TOFFSET (u_long)(60*60*24*(365*NYEARS + (NYEARS/4)))
  54
  55 static void do_close (int);
  56
  57 static void
  58 do_close (int s)
  59 {
  60   int save;
  61
  62   save = errno;
  63   __close (s);
  64   __set_errno (save);
  65 }
  66
  67 int
  68 rtime (struct sockaddr_in *addrp, struct rpc_timeval *timep,
  69        struct rpc_timeval *timeout)
  70 {
  71   int s;
  72   struct pollfd fd;
  73   int milliseconds;
  74   int res;
  75   /* RFC 868 says the time is transmitted as a 32-bit value.  */
  76   uint32_t thetime;
  77   struct sockaddr_in from;
  78   socklen_t fromlen;
  79   int type;
  80
  81   if (timeout == NULL)
  82     type = SOCK_STREAM;
  83   else
  84     type = SOCK_DGRAM;
  85
  86   s = __socket (AF_INET, type, 0);
  87   if (s < 0)
  88     return (-1);
  89
  90   addrp->sin_family = AF_INET;
  91   addrp->sin_port = htons (IPPORT_TIMESERVER);
  92   if (type == SOCK_DGRAM)
  93     {
  94       res = __sendto (s, (char *) &thetime, sizeof (thetime), 0,
  95                       (struct sockaddr *) addrp, sizeof (*addrp));
  96       if (res < 0)
  97         {
  98           do_close (s);
  99           return -1;
 100         }
 101       milliseconds = (timeout->tv_sec * 1000) + (timeout->tv_usec / 1000);
 102       fd.fd = s;
 103       fd.events = POLLIN;
 104       do
 105         res = __poll (&fd, 1, milliseconds);
 106       while (res < 0 && errno == EINTR);
 107       if (res <= 0)
 108         {
 109           if (res == 0)
 110             __set_errno (ETIMEDOUT);
 111           do_close (s);
 112           return (-1);
 113         }
 114       fromlen = sizeof (from);
 115       res = __recvfrom (s, (char *) &thetime, sizeof (thetime), 0,
 116                         (struct sockaddr *) &from, &fromlen);
 117       do_close (s);
 118       if (res < 0)
 119         return -1;
 120     }
 121   else
 122     {
 123       if (__connect (s, (struct sockaddr *) addrp, sizeof (*addrp)) < 0)
 124         {
 125           do_close (s);
 126           return -1;
 127         }
 128       res = __read (s, (char *) &thetime, sizeof (thetime));
 129       do_close (s);
 130       if (res < 0)
 131         return (-1);
 132     }
 133   if (res != sizeof (thetime))
 134     {
 135       __set_errno (EIO);
 136       return -1;
 137     }
 138   thetime = ntohl (thetime);
 139   timep->tv_sec = thetime - TOFFSET;
 140   timep->tv_usec = 0;
 141   return 0;
 142 }
 143 libc_hidden_nolink (rtime, GLIBC_2_1)