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 2.1 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 */