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 2.1 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 #include <pulsecore/core-util.h>
  47 #include <pulse/util.h>
  48
  49 #include "poll.h"
  50
  51 /* Mac OSX fails to implement poll() in a working way since 10.4. IOW, for
  52  * several years. We need to enable a dirty workaround and emulate that call
  53  * with select(), just like for Windows. sic! */
  54
  55 #if !defined(HAVE_POLL_H) || defined(OS_IS_DARWIN)
  56
  57 int pa_poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
  58     struct timeval tv;
  59     fd_set rset, wset, xset;
  60     struct pollfd *f;
  61     int ready;
  62     int maxfd = 0;
  63     char data[64];
  64
  65     FD_ZERO (&rset);
  66     FD_ZERO (&wset);
  67     FD_ZERO (&xset);
  68
  69     if (nfds == 0) {
  70         if (timeout >= 0) {
  71             pa_msleep(timeout);
  72             return 0;
  73         }
  74
  75 #ifdef OS_IS_WIN32
  76         /*
  77          * Windows does not support signals properly so waiting for them would
  78          * mean a deadlock.
  79          */
  80         pa_msleep(100);
  81         return 0;
  82 #else
  83         return select(0, NULL, NULL, NULL, NULL);
  84 #endif
  85     }
  86
  87     for (f = fds; f < &fds[nfds]; ++f) {
  88         if (f->fd != -1) {
  89             if (f->events & POLLIN)
  90                 FD_SET (f->fd, &rset);
  91             if (f->events & POLLOUT)
  92                 FD_SET (f->fd, &wset);
  93             if (f->events & POLLPRI)
  94                 FD_SET (f->fd, &xset);
  95             if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
  96                 maxfd = f->fd;
  97         }
  98     }
  99
 100     tv.tv_sec = timeout / 1000;
 101     tv.tv_usec = (timeout % 1000) * 1000;
 102
 103     ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 104                     SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 105                     SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 106     if ((ready == -1) && (errno == EBADF)) {
 107         ready = 0;
 108
 109         FD_ZERO (&rset);
 110         FD_ZERO (&wset);
 111         FD_ZERO (&xset);
 112
 113         maxfd = -1;
 114
 115         for (f = fds; f < &fds[nfds]; ++f) {
 116             if (f->fd != -1) {
 117                 fd_set sngl_rset, sngl_wset, sngl_xset;
 118
 119                 FD_ZERO (&sngl_rset);
 120                 FD_ZERO (&sngl_wset);
 121                 FD_ZERO (&sngl_xset);
 122
 123                 if (f->events & POLLIN)
 124                     FD_SET (f->fd, &sngl_rset);
 125                 if (f->events & POLLOUT)
 126                     FD_SET (f->fd, &sngl_wset);
 127                 if (f->events & POLLPRI)
 128                     FD_SET (f->fd, &sngl_xset);
 129                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 130                     struct timeval singl_tv;
 131
 132                     singl_tv.tv_sec = 0;
 133                     singl_tv.tv_usec = 0;
 134
 135                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 136                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 137                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 138                         if (f->events & POLLIN)
 139                             FD_SET (f->fd, &rset);
 140                         if (f->events & POLLOUT)
 141                             FD_SET (f->fd, &wset);
 142                         if (f->events & POLLPRI)
 143                             FD_SET (f->fd, &xset);
 144                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 145                             maxfd = f->fd;
 146                         ++ready;
 147                     } else if (errno == EBADF)
 148                         f->revents |= POLLNVAL;
 149                 }
 150             }
 151         }
 152
 153         if (ready) {
 154         /* Linux alters the tv struct... but it shouldn't matter here ...
 155          * as we're going to be a little bit out anyway as we've just eaten
 156          * more than a couple of cpu cycles above */
 157             ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 158                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 159                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 160         }
 161     }
 162
 163 #ifdef OS_IS_WIN32
 164     errno = WSAGetLastError();
 165 #endif
 166
 167     if (ready > 0) {
 168         ready = 0;
 169         for (f = fds; f < &fds[nfds]; ++f) {
 170             f->revents = 0;
 171             if (f->fd != -1) {
 172                 if (FD_ISSET (f->fd, &rset)) {
 173                     /* support for POLLHUP.  An hung up descriptor does not
 174                        increase the return value! */
 175                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 176                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 177                             errno == ECONNABORTED || errno == ENETRESET) {
 178                             fprintf(stderr, "Hangup\n");
 179                             f->revents |= POLLHUP;
 180                         }
 181                     }
 182
 183                     if (f->revents == 0)
 184                         f->revents |= POLLIN;
 185                 }
 186                 if (FD_ISSET (f->fd, &wset))
 187                     f->revents |= POLLOUT;
 188                 if (FD_ISSET (f->fd, &xset))
 189                     f->revents |= POLLPRI;
 190             }
 191             if (f->revents)
 192                 ready++;
 193         }
 194     }
 195
 196     return ready;
 197 }
 198
 199 #endif /* HAVE_SYS_POLL_H */