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 #ifdef HAVE_SYS_IOCTL_H
  39 #include <sys/ioctl.h>
  40 #endif
  41
  42 #include <errno.h>
  43 #include <fcntl.h>
  44
  45 #ifdef HAVE_SYS_SELECT_H
  46 #include <sys/select.h>
  47 #endif
  48
  49 #include <pulsecore/socket.h>
  50 #include <pulsecore/core-util.h>
  51 #include <pulse/util.h>
  52
  53 #include "poll.h"
  54
  55 /* Mac OSX fails to implement poll() in a working way since 10.4. IOW, for
  56  * several years. We need to enable a dirty workaround and emulate that call
  57  * with select(), just like for Windows. sic! */
  58
  59 #if !defined(HAVE_POLL_H) || defined(OS_IS_DARWIN)
  60
  61 int pa_poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
  62     struct timeval tv;
  63     fd_set rset, wset, xset;
  64     struct pollfd *f;
  65     int ready;
  66     int maxfd = 0;
  67 #ifdef OS_IS_WIN32
  68     char data[64];
  69 #endif
  70
  71     FD_ZERO (&rset);
  72     FD_ZERO (&wset);
  73     FD_ZERO (&xset);
  74
  75     if (nfds == 0) {
  76         if (timeout >= 0) {
  77             pa_msleep(timeout);
  78             return 0;
  79         }
  80
  81 #ifdef OS_IS_WIN32
  82         /*
  83          * Windows does not support signals properly so waiting for them would
  84          * mean a deadlock.
  85          */
  86         pa_msleep(100);
  87         return 0;
  88 #else
  89         return select(0, NULL, NULL, NULL, NULL);
  90 #endif
  91     }
  92
  93     for (f = fds; f < &fds[nfds]; ++f) {
  94         if (f->fd != -1) {
  95             if (f->events & POLLIN)
  96                 FD_SET (f->fd, &rset);
  97             if (f->events & POLLOUT)
  98                 FD_SET (f->fd, &wset);
  99             if (f->events & POLLPRI)
 100                 FD_SET (f->fd, &xset);
 101             if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 102                 maxfd = f->fd;
 103         }
 104     }
 105
 106     tv.tv_sec = timeout / 1000;
 107     tv.tv_usec = (timeout % 1000) * 1000;
 108
 109     ready = select(maxfd + 1, &rset, &wset, &xset, (timeout == -1 ? NULL : &tv));
 110
 111     if ((ready == -1) && (errno == EBADF)) {
 112         ready = 0;
 113         maxfd = -1;
 114
 115 #ifdef OS_IS_WIN32
 116         /*
 117          * Windows has no fcntl(), so we have to trick around with more
 118          * select() calls to find out what went wrong
 119          */
 120
 121         FD_ZERO (&rset);
 122         FD_ZERO (&wset);
 123         FD_ZERO (&xset);
 124
 125         for (f = fds; f < &fds[nfds]; ++f) {
 126             if (f->fd != -1) {
 127                 fd_set sngl_rset, sngl_wset, sngl_xset;
 128
 129                 FD_ZERO (&sngl_rset);
 130                 FD_ZERO (&sngl_wset);
 131                 FD_ZERO (&sngl_xset);
 132
 133                 if (f->events & POLLIN)
 134                     FD_SET (f->fd, &sngl_rset);
 135                 if (f->events & POLLOUT)
 136                     FD_SET (f->fd, &sngl_wset);
 137                 if (f->events & POLLPRI)
 138                     FD_SET (f->fd, &sngl_xset);
 139                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 140                     struct timeval singl_tv;
 141
 142                     singl_tv.tv_sec = 0;
 143                     singl_tv.tv_usec = 0;
 144
 145                     if (select(f->fd, &rset, &wset, &xset, &singl_tv) != -1) {
 146                         if (f->events & POLLIN)
 147                             FD_SET (f->fd, &rset);
 148                         if (f->events & POLLOUT)
 149                             FD_SET (f->fd, &wset);
 150                         if (f->events & POLLPRI)
 151                             FD_SET (f->fd, &xset);
 152                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 153                             maxfd = f->fd;
 154                         ++ready;
 155                     } else if (errno == EBADF)
 156                         f->revents |= POLLNVAL;
 157                 }
 158             }
 159         }
 160
 161 #else /* !OS_IS_WIN32 */
 162
 163         for (f = fds; f < &fds[nfds]; f++)
 164             if (f->fd != -1) {
 165                 /* use fcntl() to find out whether the descriptor is valid */
 166                 if (fcntl(f->fd, F_GETFL) != -1) {
 167                     if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI))) {
 168                         maxfd = f->fd;
 169                         ready++;
 170                     }
 171                 } else {
 172                     FD_CLR(f->fd, &rset);
 173                     FD_CLR(f->fd, &wset);
 174                     FD_CLR(f->fd, &xset);
 175                 }
 176             }
 177
 178 #endif
 179
 180         if (ready) {
 181         /* Linux alters the tv struct... but it shouldn't matter here ...
 182          * as we're going to be a little bit out anyway as we've just eaten
 183          * more than a couple of cpu cycles above */
 184             ready = select(maxfd + 1, &rset, &wset, &xset, (timeout == -1 ? NULL : &tv));
 185         }
 186     }
 187
 188 #ifdef OS_IS_WIN32
 189     errno = WSAGetLastError();
 190 #endif
 191
 192     if (ready > 0) {
 193         ready = 0;
 194         for (f = fds; f < &fds[nfds]; ++f) {
 195             f->revents = 0;
 196             if (f->fd != -1) {
 197                 if (FD_ISSET (f->fd, &rset)) {
 198                     /* support for POLLHUP.  An hung up descriptor does not
 199                        increase the return value! */
 200 #ifdef OS_IS_DARWIN
 201                     /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
 202                      * for some kinds of descriptors.  Detect if this descriptor is a
 203                      * connected socket, a server socket, or something else using a
 204                      * 0-byte recv, and use ioctl(2) to detect POLLHUP.  */
 205                     int r = recv(f->fd, NULL, 0, MSG_PEEK);
 206                     if (r == 0 || (r < 0 && errno == ENOTSOCK))
 207                         ioctl(f->fd, FIONREAD, &r);
 208
 209                     if (r == 0)
 210                         f->revents |= POLLHUP;
 211 #else /* !OS_IS_DARWIN */
 212                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 213                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 214                             errno == ECONNABORTED || errno == ENETRESET) {
 215                             fprintf(stderr, "Hangup\n");
 216                             f->revents |= POLLHUP;
 217                         }
 218                     }
 219 #endif
 220
 221                     if (f->revents == 0)
 222                         f->revents |= POLLIN;
 223                 }
 224                 if (FD_ISSET (f->fd, &wset))
 225                     f->revents |= POLLOUT;
 226                 if (FD_ISSET (f->fd, &xset))
 227                     f->revents |= POLLPRI;
 228             }
 229             if (f->revents)
 230                 ready++;
 231         }
 232     }
 233
 234     return ready;
 235 }
 236
 237 #endif /* HAVE_SYS_POLL_H */