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

   1 /* $Id$ */
   2
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   8
   9   PulseAudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as published
  11   by the Free Software Foundation; either version 2 of the License,
  12   or (at your option) any later version.
  13
  14   PulseAudio 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   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with PulseAudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 /***
  26    Based on work for the GNU C Library.
  27    Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
  28 ***/
  29
  30 /* Poll the file descriptors described by the NFDS structures starting at
  31    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  32    an event to occur; if TIMEOUT is -1, block until an event occurs.
  33    Returns the number of file descriptors with events, zero if timed out,
  34    or -1 for errors.  */
  35
  36 #ifdef HAVE_CONFIG_H
  37 #include <config.h>
  38 #endif
  39
  40 #include <errno.h>
  41
  42 #ifdef HAVE_SYS_SELECT_H
  43 #include <sys/select.h>
  44 #endif
  45
  46 #include "winsock.h"
  47
  48 #ifndef HAVE_SYS_POLL_H
  49
  50 #include <pulsecore/core-util.h>
  51
  52 #include "poll.h"
  53
  54 int poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
  55     struct timeval tv;
  56     fd_set rset, wset, xset;
  57     struct pollfd *f;
  58     int ready;
  59     int maxfd = 0;
  60     char data[64];
  61
  62     FD_ZERO (&rset);
  63     FD_ZERO (&wset);
  64     FD_ZERO (&xset);
  65
  66     if (nfds == 0) {
  67         if (timeout >= 0) {
  68             pa_msleep(timeout);
  69             return 0;
  70         }
  71
  72 #ifdef OS_IS_WIN32
  73         /*
  74          * Windows does not support signals properly so waiting for them would
  75          * mean a deadlock.
  76          */
  77         pa_msleep(100);
  78         return 0;
  79 #else
  80         return select(0, NULL, NULL, NULL, NULL);
  81 #endif
  82     }
  83
  84     for (f = fds; f < &fds[nfds]; ++f) {
  85         if (f->fd != -1) {
  86             if (f->events & POLLIN)
  87                 FD_SET (f->fd, &rset);
  88             if (f->events & POLLOUT)
  89                 FD_SET (f->fd, &wset);
  90             if (f->events & POLLPRI)
  91                 FD_SET (f->fd, &xset);
  92             if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
  93                 maxfd = f->fd;
  94         }
  95     }
  96
  97     tv.tv_sec = timeout / 1000;
  98     tv.tv_usec = (timeout % 1000) * 1000;
  99
 100     ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 101                     SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 102                     SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 103     if ((ready == -1) && (errno == EBADF)) {
 104         ready = 0;
 105
 106         FD_ZERO (&rset);
 107         FD_ZERO (&wset);
 108         FD_ZERO (&xset);
 109
 110         maxfd = -1;
 111
 112         for (f = fds; f < &fds[nfds]; ++f) {
 113             if (f->fd != -1) {
 114                 fd_set sngl_rset, sngl_wset, sngl_xset;
 115
 116                 FD_ZERO (&sngl_rset);
 117                 FD_ZERO (&sngl_wset);
 118                 FD_ZERO (&sngl_xset);
 119
 120                 if (f->events & POLLIN)
 121                     FD_SET (f->fd, &sngl_rset);
 122                 if (f->events & POLLOUT)
 123                     FD_SET (f->fd, &sngl_wset);
 124                 if (f->events & POLLPRI)
 125                     FD_SET (f->fd, &sngl_xset);
 126                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 127                     struct timeval singl_tv;
 128
 129                     singl_tv.tv_sec = 0;
 130                     singl_tv.tv_usec = 0;
 131
 132                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 133                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 134                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 135                         if (f->events & POLLIN)
 136                             FD_SET (f->fd, &rset);
 137                         if (f->events & POLLOUT)
 138                             FD_SET (f->fd, &wset);
 139                         if (f->events & POLLPRI)
 140                             FD_SET (f->fd, &xset);
 141                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 142                             maxfd = f->fd;
 143                         ++ready;
 144                     } else if (errno == EBADF)
 145                         f->revents |= POLLNVAL;
 146                 }
 147             }
 148         }
 149
 150         if (ready) {
 151         /* Linux alters the tv struct... but it shouldn't matter here ...
 152          * as we're going to be a little bit out anyway as we've just eaten
 153          * more than a couple of cpu cycles above */
 154             ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 155                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 156                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 157         }
 158     }
 159
 160 #ifdef OS_IS_WIN32
 161     errno = WSAGetLastError();
 162 #endif
 163
 164     if (ready > 0) {
 165         ready = 0;
 166         for (f = fds; f < &fds[nfds]; ++f) {
 167             f->revents = 0;
 168             if (f->fd != -1) {
 169                 if (FD_ISSET (f->fd, &rset)) {
 170                     /* support for POLLHUP.  An hung up descriptor does not
 171                        increase the return value! */
 172                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 173                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 174                             errno == ECONNABORTED || errno == ENETRESET) {
 175                             fprintf(stderr, "Hangup\n");
 176                             f->revents |= POLLHUP;
 177                         }
 178                     }
 179
 180                     if (f->revents == 0)
 181                         f->revents |= POLLIN;
 182                 }
 183                 if (FD_ISSET (f->fd, &wset))
 184                     f->revents |= POLLOUT;
 185                 if (FD_ISSET (f->fd, &xset))
 186                     f->revents |= POLLPRI;
 187             }
 188             if (f->revents)
 189                 ready++;
 190         }
 191     }
 192
 193     return ready;
 194 }
 195
 196 #endif /* HAVE_SYS_POLL_H */