minix/lib/libc/sys/poll.c

   1 /*      $NetBSD: poll.c,v 1.3 2008/04/29 05:46:08 martin Exp $  */
   2
   3 /*-
   4  * Copyright (c) 2003 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Charles Blundell.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #include "namespace.h"
  34 #include <lib.h>
  35
  36 #include <sys/types.h>
  37 #include <sys/time.h>
  38 #include <unistd.h>
  39 #include <sys/poll.h>
  40 #include <errno.h>
  41
  42 int
  43 poll(struct pollfd *p, nfds_t nfds, int timout)
  44 {
  45         fd_set rd, wr, except;
  46         struct timeval tv;
  47         nfds_t i;
  48         int highfd, rval;
  49
  50         /*
  51          * select cannot tell us much wrt POLL*BAND, POLLPRI, POLLHUP or
  52          * POLLNVAL.
  53          */
  54         FD_ZERO(&rd);
  55         FD_ZERO(&wr);
  56         FD_ZERO(&except);
  57
  58         highfd = -1;
  59         for (i = 0; i < nfds; i++) {
  60                 p[i].revents = 0;
  61                 if (p[i].fd < 0)
  62                         continue;
  63                 if (p[i].fd >= FD_SETSIZE) {
  64                         errno = EINVAL;
  65                         return -1;
  66                 }
  67                 if (p[i].fd > highfd)
  68                         highfd = p[i].fd;
  69
  70                 if (p[i].events & (POLLIN|POLLRDNORM))
  71                         FD_SET(p[i].fd, &rd);
  72                 if (p[i].events & (POLLOUT|POLLWRNORM|POLLWRBAND))
  73                         FD_SET(p[i].fd, &wr);
  74                 if (p[i].events & (POLLRDBAND|POLLPRI))
  75                         FD_SET(p[i].fd, &except);
  76         }
  77
  78         tv.tv_sec = timout / 1000;
  79         tv.tv_usec = (timout % 1000) * 1000;
  80
  81         rval = select(highfd + 1, &rd, &wr, &except,
  82                 timout == -1 ? NULL : &tv);
  83         if (rval <= 0)
  84                 return rval;
  85
  86         rval = 0;
  87         for (i = 0; i < nfds; i++) {
  88                 if (p[i].fd < 0)
  89                         continue;
  90                 if (FD_ISSET(p[i].fd, &rd))
  91                         p[i].revents |= p[i].events & (POLLIN|POLLRDNORM);
  92                 if (FD_ISSET(p[i].fd, &wr))
  93                         p[i].revents |=
  94                             p[i].events & (POLLOUT|POLLWRNORM|POLLWRBAND);
  95                 if (FD_ISSET(p[i].fd, &except))
  96                         p[i].revents |= p[i].events & (POLLRDBAND|POLLPRI);
  97                 /* XXX: POLLERR/POLLHUP/POLLNVAL? */
  98                 if (p[i].revents != 0)
  99                         rval++;
 100         }
 101         return rval;
 102 }