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
  44 #ifdef HAVE_SYS_SELECT_H
  45 #include <sys/select.h>
  46 #endif
  47
  48 #include "winsock.h"
  49
  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 ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 110                     SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 111                     SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 112
 113     if ((ready == -1) && (errno == EBADF)) {
 114         ready = 0;
 115
 116         FD_ZERO (&rset);
 117         FD_ZERO (&wset);
 118         FD_ZERO (&xset);
 119
 120         maxfd = -1;
 121
 122         for (f = fds; f < &fds[nfds]; ++f) {
 123             if (f->fd != -1) {
 124                 fd_set sngl_rset, sngl_wset, sngl_xset;
 125
 126                 FD_ZERO (&sngl_rset);
 127                 FD_ZERO (&sngl_wset);
 128                 FD_ZERO (&sngl_xset);
 129
 130                 if (f->events & POLLIN)
 131                     FD_SET (f->fd, &sngl_rset);
 132                 if (f->events & POLLOUT)
 133                     FD_SET (f->fd, &sngl_wset);
 134                 if (f->events & POLLPRI)
 135                     FD_SET (f->fd, &sngl_xset);
 136                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 137                     struct timeval singl_tv;
 138
 139                     singl_tv.tv_sec = 0;
 140                     singl_tv.tv_usec = 0;
 141
 142                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 143                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 144                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 145                         if (f->events & POLLIN)
 146                             FD_SET (f->fd, &rset);
 147                         if (f->events & POLLOUT)
 148                             FD_SET (f->fd, &wset);
 149                         if (f->events & POLLPRI)
 150                             FD_SET (f->fd, &xset);
 151                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 152                             maxfd = f->fd;
 153                         ++ready;
 154                     } else if (errno == EBADF)
 155                         f->revents |= POLLNVAL;
 156                 }
 157             }
 158         }
 159
 160         if (ready) {
 161         /* Linux alters the tv struct... but it shouldn't matter here ...
 162          * as we're going to be a little bit out anyway as we've just eaten
 163          * more than a couple of cpu cycles above */
 164             ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 165                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 166                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 167         }
 168     }
 169
 170 #ifdef OS_IS_WIN32
 171     errno = WSAGetLastError();
 172 #endif
 173
 174     if (ready > 0) {
 175         int r;
 176
 177         ready = 0;
 178         for (f = fds; f < &fds[nfds]; ++f) {
 179             f->revents = 0;
 180             if (f->fd != -1) {
 181                 if (FD_ISSET (f->fd, &rset)) {
 182                     /* support for POLLHUP.  An hung up descriptor does not
 183                        increase the return value! */
 184 #ifdef OS_IS_DARWIN
 185                     /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
 186                      * for some kinds of descriptors.  Detect if this descriptor is a
 187                      * connected socket, a server socket, or something else using a
 188                      * 0-byte recv, and use ioctl(2) to detect POLLHUP.  */
 189                     r = recv(f->fd, NULL, 0, MSG_PEEK);
 190                     if (r == 0 || (r < 0 && errno == ENOTSOCK))
 191                         ioctl(f->fd, FIONREAD, &r);
 192
 193                     if (r == 0)
 194                         f->revents |= POLLHUP;
 195 #else /* !OS_IS_DARWIN */
 196                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 197                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 198                             errno == ECONNABORTED || errno == ENETRESET) {
 199                             fprintf(stderr, "Hangup\n");
 200                             f->revents |= POLLHUP;
 201                         }
 202                     }
 203 #endif
 204
 205                     if (f->revents == 0)
 206                         f->revents |= POLLIN;
 207                 }
 208                 if (FD_ISSET (f->fd, &wset))
 209                     f->revents |= POLLOUT;
 210                 if (FD_ISSET (f->fd, &xset))
 211                     f->revents |= POLLPRI;
 212             }
 213             if (f->revents)
 214                 ready++;
 215         }
 216     }
 217
 218     return ready;
 219 }
 220
 221 #endif /* HAVE_SYS_POLL_H */