code.delx.au - pulseaudio/blob - src/polypcore/poll.c

   1 /* $Id$ */
   2
   3 /***
   4    Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
   5    Copyright (C) 2005, Cendio AB.
   6    This file is part of polypaudio.
   7    Based on work for the GNU C Library.
   8
   9    polypaudio is free software; you can redistribute it and/or modify it
  10    under the terms of the GNU Library General Public License as published
  11    by the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    polypaudio is distributed in the hope that it will be useful, but
  15    WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17    Library General Public License for more details.
  18
  19    You should have received a copy of the GNU Library General Public
  20    License along with polypaudio; If not, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  22    USA.
  23 ***/
  24
  25 /* Poll the file descriptors described by the NFDS structures starting at
  26    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  27    an event to occur; if TIMEOUT is -1, block until an event occurs.
  28    Returns the number of file descriptors with events, zero if timed out,
  29    or -1 for errors.  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include <config.h>
  33 #endif
  34
  35 #include <errno.h>
  36
  37 #ifdef HAVE_SYS_SELECT_H
  38 #include <sys/select.h>
  39 #endif
  40
  41 #include "winsock.h"
  42
  43 #ifndef HAVE_SYS_POLL_H
  44
  45 #include <polypcore/core-util.h>
  46
  47 #include "poll.h"
  48
  49 int poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
  50     struct timeval tv;
  51     fd_set rset, wset, xset;
  52     struct pollfd *f;
  53     int ready;
  54     int maxfd = 0;
  55     char data[64];
  56
  57     FD_ZERO (&rset);
  58     FD_ZERO (&wset);
  59     FD_ZERO (&xset);
  60
  61     if (nfds == 0) {
  62         if (timeout >= 0) {
  63             pa_msleep(timeout);
  64             return 0;
  65         }
  66
  67 #ifdef OS_IS_WIN32
  68         /*
  69          * Windows does not support signals properly so waiting for them would
  70          * mean a deadlock.
  71          */
  72         pa_msleep(100);
  73         return 0;
  74 #else
  75         return select(0, NULL, NULL, NULL, NULL);
  76 #endif
  77     }
  78
  79     for (f = fds; f < &fds[nfds]; ++f) {
  80         if (f->fd != -1) {
  81             if (f->events & POLLIN)
  82                 FD_SET (f->fd, &rset);
  83             if (f->events & POLLOUT)
  84                 FD_SET (f->fd, &wset);
  85             if (f->events & POLLPRI)
  86                 FD_SET (f->fd, &xset);
  87             if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
  88                 maxfd = f->fd;
  89         }
  90     }
  91
  92     tv.tv_sec = timeout / 1000;
  93     tv.tv_usec = (timeout % 1000) * 1000;
  94
  95     ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
  96                     SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
  97                     SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
  98     if ((ready == -1) && (errno == EBADF)) {
  99         ready = 0;
 100
 101         FD_ZERO (&rset);
 102         FD_ZERO (&wset);
 103         FD_ZERO (&xset);
 104
 105         maxfd = -1;
 106
 107         for (f = fds; f < &fds[nfds]; ++f) {
 108             if (f->fd != -1) {
 109                 fd_set sngl_rset, sngl_wset, sngl_xset;
 110
 111                 FD_ZERO (&sngl_rset);
 112                 FD_ZERO (&sngl_wset);
 113                 FD_ZERO (&sngl_xset);
 114
 115                 if (f->events & POLLIN)
 116                     FD_SET (f->fd, &sngl_rset);
 117                 if (f->events & POLLOUT)
 118                     FD_SET (f->fd, &sngl_wset);
 119                 if (f->events & POLLPRI)
 120                     FD_SET (f->fd, &sngl_xset);
 121                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 122                     struct timeval singl_tv;
 123
 124                     singl_tv.tv_sec = 0;
 125                     singl_tv.tv_usec = 0;
 126
 127                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 128                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 129                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 130                         if (f->events & POLLIN)
 131                             FD_SET (f->fd, &rset);
 132                         if (f->events & POLLOUT)
 133                             FD_SET (f->fd, &wset);
 134                         if (f->events & POLLPRI)
 135                             FD_SET (f->fd, &xset);
 136                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 137                             maxfd = f->fd;
 138                         ++ready;
 139                     } else if (errno == EBADF)
 140                         f->revents |= POLLNVAL;
 141                 }
 142             }
 143         }
 144
 145         if (ready) {
 146         /* Linux alters the tv struct... but it shouldn't matter here ...
 147          * as we're going to be a little bit out anyway as we've just eaten
 148          * more than a couple of cpu cycles above */
 149             ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 150                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 151                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 152         }
 153     }
 154
 155 #ifdef OS_IS_WIN32
 156     errno = WSAGetLastError();
 157 #endif
 158
 159     if (ready > 0) {
 160         ready = 0;
 161         for (f = fds; f < &fds[nfds]; ++f) {
 162             f->revents = 0;
 163             if (f->fd != -1) {
 164                 if (FD_ISSET (f->fd, &rset)) {
 165                     /* support for POLLHUP.  An hung up descriptor does not
 166                        increase the return value! */
 167                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 168                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 169                             errno == ECONNABORTED || errno == ENETRESET) {
 170                             fprintf(stderr, "Hangup\n");
 171                             f->revents |= POLLHUP;
 172                         }
 173                     }
 174
 175                     if (f->revents == 0)
 176                         f->revents |= POLLIN;
 177                 }
 178                 if (FD_ISSET (f->fd, &wset))
 179                     f->revents |= POLLOUT;
 180                 if (FD_ISSET (f->fd, &xset))
 181                     f->revents |= POLLPRI;
 182             }
 183             if (f->revents)
 184                 ready++;
 185         }
 186     }
 187
 188     return ready;
 189 }
 190
 191 #endif /* HAVE_SYS_POLL_H */