src/protocols/zephyr/ZWait4Not.c

   1 /* This file is part of the Project Athena Zephyr Notification System.
   2  * It contains the ZCheckIfNotice/select loop used for waiting for
   3  * a notice, with a timeout.
   4  *
   5  *      Created by:     <Joe Random Hacker>
   6  *
   7  *      $Source$
   8  *      $Author: warmenhoven $
   9  *
  10  *      Copyright (c) 1991 by the Massachusetts Institute of Technology.
  11  *      For copying and distribution information, see the file
  12  *      "mit-copyright.h".
  13  */
  14
  15 #include "mit-copyright.h"
  16
  17 #ifndef lint
  18 static char rcsid_ZWaitForNotice_c[] = "$Zephyr$";
  19 #endif
  20
  21 #include <internal.h>
  22 #include <sys/socket.h>
  23
  24 Code_t Z_WaitForNotice (notice, pred, arg, timeout)
  25      ZNotice_t *notice;
  26      int (*pred) __P((ZNotice_t *, void *));
  27      void *arg;
  28      int timeout;
  29 {
  30   Code_t retval;
  31   struct timeval tv, t0;
  32   fd_set fdmask;
  33   int i, fd;
  34
  35   retval = ZCheckIfNotice (notice, (struct sockaddr_in *) 0, pred,
  36                            (char *) arg);
  37   if (retval == ZERR_NONE)
  38     return ZERR_NONE;
  39   if (retval != ZERR_NONOTICE)
  40     return retval;
  41
  42   fd = ZGetFD ();
  43   FD_ZERO (&fdmask);
  44   tv.tv_sec = timeout;
  45   tv.tv_usec = 0;
  46   gettimeofday (&t0, (struct timezone *) 0);
  47   t0.tv_sec += timeout;
  48   while (1) {
  49     FD_SET (fd, &fdmask);
  50     i = select (fd + 1, &fdmask, (fd_set *) 0, (fd_set *) 0, &tv);
  51     if (i == 0)
  52       return ETIMEDOUT;
  53     if (i < 0 && errno != EINTR)
  54       return errno;
  55     if (i > 0) {
  56       retval = ZCheckIfNotice (notice, (struct sockaddr_in *) 0, pred,
  57                                (char *) arg);
  58       if (retval != ZERR_NONOTICE) /* includes ZERR_NONE */
  59         return retval;
  60     }
  61     gettimeofday (&tv, (struct timezone *) 0);
  62     tv.tv_usec = t0.tv_usec - tv.tv_usec;
  63     if (tv.tv_usec < 0) {
  64       tv.tv_usec += 1000000;
  65       tv.tv_sec = t0.tv_sec - tv.tv_sec - 1;
  66     }
  67     else
  68       tv.tv_sec = t0.tv_sec - tv.tv_sec;
  69   }
  70   /*NOTREACHED*/
  71 }