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

   1
   2 /***
   3   This file is part of PulseAudio.
   4
   5   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   6
   7   PulseAudio is free software; you can redistribute it and/or modify
   8   it under the terms of the GNU Lesser General Public License as published
   9   by the Free Software Foundation; either version 2 of the License,
  10   or (at your option) any later version.
  11
  12   PulseAudio is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with PulseAudio; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  20   USA.
  21 ***/
  22
  23 /***
  24    Based on work for the GNU C Library.
  25    Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
  26 ***/
  27
  28 /* Poll the file descriptors described by the NFDS structures starting at
  29    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  30    an event to occur; if TIMEOUT is -1, block until an event occurs.
  31    Returns the number of file descriptors with events, zero if timed out,
  32    or -1 for errors.  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 #include <errno.h>
  39
  40 #ifdef HAVE_SYS_SELECT_H
  41 #include <sys/select.h>
  42 #endif
  43
  44 #include "winsock.h"
  45
  46 #ifndef HAVE_POLL_H
  47
  48 #include <pulsecore/core-util.h>
  49
  50 #include "poll.h"
  51
  52 int poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
  53     struct timeval tv;
  54     fd_set rset, wset, xset;
  55     struct pollfd *f;
  56     int ready;
  57     int maxfd = 0;
  58     char data[64];
  59
  60     FD_ZERO (&rset);
  61     FD_ZERO (&wset);
  62     FD_ZERO (&xset);
  63
  64     if (nfds == 0) {
  65         if (timeout >= 0) {
  66             pa_msleep(timeout);
  67             return 0;
  68         }
  69
  70 #ifdef OS_IS_WIN32
  71         /*
  72          * Windows does not support signals properly so waiting for them would
  73          * mean a deadlock.
  74          */
  75         pa_msleep(100);
  76         return 0;
  77 #else
  78         return select(0, NULL, NULL, NULL, NULL);
  79 #endif
  80     }
  81
  82     for (f = fds; f < &fds[nfds]; ++f) {
  83         if (f->fd != -1) {
  84             if (f->events & POLLIN)
  85                 FD_SET (f->fd, &rset);
  86             if (f->events & POLLOUT)
  87                 FD_SET (f->fd, &wset);
  88             if (f->events & POLLPRI)
  89                 FD_SET (f->fd, &xset);
  90             if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
  91                 maxfd = f->fd;
  92         }
  93     }
  94
  95     tv.tv_sec = timeout / 1000;
  96     tv.tv_usec = (timeout % 1000) * 1000;
  97
  98     ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
  99                     SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 100                     SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 101     if ((ready == -1) && (errno == EBADF)) {
 102         ready = 0;
 103
 104         FD_ZERO (&rset);
 105         FD_ZERO (&wset);
 106         FD_ZERO (&xset);
 107
 108         maxfd = -1;
 109
 110         for (f = fds; f < &fds[nfds]; ++f) {
 111             if (f->fd != -1) {
 112                 fd_set sngl_rset, sngl_wset, sngl_xset;
 113
 114                 FD_ZERO (&sngl_rset);
 115                 FD_ZERO (&sngl_wset);
 116                 FD_ZERO (&sngl_xset);
 117
 118                 if (f->events & POLLIN)
 119                     FD_SET (f->fd, &sngl_rset);
 120                 if (f->events & POLLOUT)
 121                     FD_SET (f->fd, &sngl_wset);
 122                 if (f->events & POLLPRI)
 123                     FD_SET (f->fd, &sngl_xset);
 124                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 125                     struct timeval singl_tv;
 126
 127                     singl_tv.tv_sec = 0;
 128                     singl_tv.tv_usec = 0;
 129
 130                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 131                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 132                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 133                         if (f->events & POLLIN)
 134                             FD_SET (f->fd, &rset);
 135                         if (f->events & POLLOUT)
 136                             FD_SET (f->fd, &wset);
 137                         if (f->events & POLLPRI)
 138                             FD_SET (f->fd, &xset);
 139                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 140                             maxfd = f->fd;
 141                         ++ready;
 142                     } else if (errno == EBADF)
 143                         f->revents |= POLLNVAL;
 144                 }
 145             }
 146         }
 147
 148         if (ready) {
 149         /* Linux alters the tv struct... but it shouldn't matter here ...
 150          * as we're going to be a little bit out anyway as we've just eaten
 151          * more than a couple of cpu cycles above */
 152             ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 153                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 154                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 155         }
 156     }
 157
 158 #ifdef OS_IS_WIN32
 159     errno = WSAGetLastError();
 160 #endif
 161
 162     if (ready > 0) {
 163         ready = 0;
 164         for (f = fds; f < &fds[nfds]; ++f) {
 165             f->revents = 0;
 166             if (f->fd != -1) {
 167                 if (FD_ISSET (f->fd, &rset)) {
 168                     /* support for POLLHUP.  An hung up descriptor does not
 169                        increase the return value! */
 170                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 171                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 172                             errno == ECONNABORTED || errno == ENETRESET) {
 173                             fprintf(stderr, "Hangup\n");
 174                             f->revents |= POLLHUP;
 175                         }
 176                     }
 177
 178                     if (f->revents == 0)
 179                         f->revents |= POLLIN;
 180                 }
 181                 if (FD_ISSET (f->fd, &wset))
 182                     f->revents |= POLLOUT;
 183                 if (FD_ISSET (f->fd, &xset))
 184                     f->revents |= POLLPRI;
 185             }
 186             if (f->revents)
 187                 ready++;
 188         }
 189     }
 190
 191     return ready;
 192 }
 193
 194 #endif /* HAVE_SYS_POLL_H */