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((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         maxfd = -1;
 116
 117 #ifdef OS_IS_WIN32
 118         /*
 119          * Windows has no fcntl(), so we have to trick around with more
 120          * select() calls to find out what went wrong
 121          */
 122
 123         FD_ZERO (&rset);
 124         FD_ZERO (&wset);
 125         FD_ZERO (&xset);
 126
 127         for (f = fds; f < &fds[nfds]; ++f) {
 128             if (f->fd != -1) {
 129                 fd_set sngl_rset, sngl_wset, sngl_xset;
 130
 131                 FD_ZERO (&sngl_rset);
 132                 FD_ZERO (&sngl_wset);
 133                 FD_ZERO (&sngl_xset);
 134
 135                 if (f->events & POLLIN)
 136                     FD_SET (f->fd, &sngl_rset);
 137                 if (f->events & POLLOUT)
 138                     FD_SET (f->fd, &sngl_wset);
 139                 if (f->events & POLLPRI)
 140                     FD_SET (f->fd, &sngl_xset);
 141                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 142                     struct timeval singl_tv;
 143
 144                     singl_tv.tv_sec = 0;
 145                     singl_tv.tv_usec = 0;
 146
 147                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 148                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 149                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 150                         if (f->events & POLLIN)
 151                             FD_SET (f->fd, &rset);
 152                         if (f->events & POLLOUT)
 153                             FD_SET (f->fd, &wset);
 154                         if (f->events & POLLPRI)
 155                             FD_SET (f->fd, &xset);
 156                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 157                             maxfd = f->fd;
 158                         ++ready;
 159                     } else if (errno == EBADF)
 160                         f->revents |= POLLNVAL;
 161                 }
 162             }
 163         }
 164
 165 #else /* !OS_IS_WIN32 */
 166
 167         for (f = fds; f < &fds[nfds]; f++)
 168             if (f->fd != -1) {
 169                 /* use fcntl() to find out whether the descriptor is valid */
 170                 if (fcntl(f->fd, F_GETFL) != -1) {
 171                     if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI))) {
 172                         maxfd = f->fd;
 173                         ready++;
 174                     }
 175                 } else {
 176                     FD_CLR(f->fd, &rset);
 177                     FD_CLR(f->fd, &wset);
 178                     FD_CLR(f->fd, &xset);
 179                 }
 180             }
 181
 182 #endif
 183
 184         if (ready) {
 185         /* Linux alters the tv struct... but it shouldn't matter here ...
 186          * as we're going to be a little bit out anyway as we've just eaten
 187          * more than a couple of cpu cycles above */
 188             ready = select((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 189                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 190                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 191         }
 192     }
 193
 194 #ifdef OS_IS_WIN32
 195     errno = WSAGetLastError();
 196 #endif
 197
 198     if (ready > 0) {
 199         int r;
 200
 201         ready = 0;
 202         for (f = fds; f < &fds[nfds]; ++f) {
 203             f->revents = 0;
 204             if (f->fd != -1) {
 205                 if (FD_ISSET (f->fd, &rset)) {
 206                     /* support for POLLHUP.  An hung up descriptor does not
 207                        increase the return value! */
 208 #ifdef OS_IS_DARWIN
 209                     /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
 210                      * for some kinds of descriptors.  Detect if this descriptor is a
 211                      * connected socket, a server socket, or something else using a
 212                      * 0-byte recv, and use ioctl(2) to detect POLLHUP.  */
 213                     r = recv(f->fd, NULL, 0, MSG_PEEK);
 214                     if (r == 0 || (r < 0 && errno == ENOTSOCK))
 215                         ioctl(f->fd, FIONREAD, &r);
 216
 217                     if (r == 0)
 218                         f->revents |= POLLHUP;
 219 #else /* !OS_IS_DARWIN */
 220                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 221                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 222                             errno == ECONNABORTED || errno == ENETRESET) {
 223                             fprintf(stderr, "Hangup\n");
 224                             f->revents |= POLLHUP;
 225                         }
 226                     }
 227 #endif
 228
 229                     if (f->revents == 0)
 230                         f->revents |= POLLIN;
 231                 }
 232                 if (FD_ISSET (f->fd, &wset))
 233                     f->revents |= POLLOUT;
 234                 if (FD_ISSET (f->fd, &xset))
 235                     f->revents |= POLLPRI;
 236             }
 237             if (f->revents)
 238                 ready++;
 239         }
 240     }
 241
 242     return ready;
 243 }
 244
 245 #endif /* HAVE_SYS_POLL_H */