code.delx.au - pulseaudio/blob - src/polypcore/poll.c

   1 /* $Id$ */
   2
   3 /***
   4    Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
   5    Copyright (C) 2005, Cendio AB.
   6    This file is part of polypaudio.
   7    Based on work for the GNU C Library.
   8
   9    polypaudio is free software; you can redistribute it and/or modify it
  10    under the terms of the GNU Library General Public License as published
  11    by the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    polypaudio is distributed in the hope that it will be useful, but
  15    WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17    Library General Public License for more details.
  18
  19    You should have received a copy of the GNU Library General Public
  20    License along with polypaudio; If not, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  22    USA.
  23 ***/
  24
  25 /* Poll the file descriptors described by the NFDS structures starting at
  26    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  27    an event to occur; if TIMEOUT is -1, block until an event occurs.
  28    Returns the number of file descriptors with events, zero if timed out,
  29    or -1 for errors.  */
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include <config.h>
  33 #endif
  34
  35 #include <errno.h>
  36
  37 #ifdef HAVE_SYS_SELECT_H
  38 #include <sys/select.h>
  39 #endif
  40
  41 #include "winsock.h"
  42
  43 #ifndef HAVE_SYS_POLL_H
  44
  45 #include "util.h"
  46 #include "poll.h"
  47
  48 int poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
  49     struct timeval tv;
  50     fd_set rset, wset, xset;
  51     struct pollfd *f;
  52     int ready;
  53     int maxfd = 0;
  54     char data[64];
  55
  56     FD_ZERO (&rset);
  57     FD_ZERO (&wset);
  58     FD_ZERO (&xset);
  59
  60     if (nfds == 0) {
  61         if (timeout >= 0) {
  62             pa_msleep(timeout);
  63             return 0;
  64         }
  65
  66 #ifdef OS_IS_WIN32
  67         /*
  68          * Windows does not support signals properly so waiting for them would
  69          * mean a deadlock.
  70          */
  71         pa_msleep(100);
  72         return 0;
  73 #else
  74         return select(0, NULL, NULL, NULL, NULL);
  75 #endif
  76     }
  77
  78     for (f = fds; f < &fds[nfds]; ++f) {
  79         if (f->fd != -1) {
  80             if (f->events & POLLIN)
  81                 FD_SET (f->fd, &rset);
  82             if (f->events & POLLOUT)
  83                 FD_SET (f->fd, &wset);
  84             if (f->events & POLLPRI)
  85                 FD_SET (f->fd, &xset);
  86             if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
  87                 maxfd = f->fd;
  88         }
  89     }
  90
  91     tv.tv_sec = timeout / 1000;
  92     tv.tv_usec = (timeout % 1000) * 1000;
  93
  94     ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
  95                     SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
  96                     SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
  97     if ((ready == -1) && (errno == EBADF)) {
  98         ready = 0;
  99
 100         FD_ZERO (&rset);
 101         FD_ZERO (&wset);
 102         FD_ZERO (&xset);
 103
 104         maxfd = -1;
 105
 106         for (f = fds; f < &fds[nfds]; ++f) {
 107             if (f->fd != -1) {
 108                 fd_set sngl_rset, sngl_wset, sngl_xset;
 109
 110                 FD_ZERO (&sngl_rset);
 111                 FD_ZERO (&sngl_wset);
 112                 FD_ZERO (&sngl_xset);
 113
 114                 if (f->events & POLLIN)
 115                     FD_SET (f->fd, &sngl_rset);
 116                 if (f->events & POLLOUT)
 117                     FD_SET (f->fd, &sngl_wset);
 118                 if (f->events & POLLPRI)
 119                     FD_SET (f->fd, &sngl_xset);
 120                 if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
 121                     struct timeval singl_tv;
 122
 123                     singl_tv.tv_sec = 0;
 124                     singl_tv.tv_usec = 0;
 125
 126                     if (select((SELECT_TYPE_ARG1) f->fd, SELECT_TYPE_ARG234 &rset,
 127                                SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 128                                SELECT_TYPE_ARG5 &singl_tv) != -1) {
 129                         if (f->events & POLLIN)
 130                             FD_SET (f->fd, &rset);
 131                         if (f->events & POLLOUT)
 132                             FD_SET (f->fd, &wset);
 133                         if (f->events & POLLPRI)
 134                             FD_SET (f->fd, &xset);
 135                         if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
 136                             maxfd = f->fd;
 137                         ++ready;
 138                     } else if (errno == EBADF)
 139                         f->revents |= POLLNVAL;
 140                 }
 141             }
 142         }
 143
 144         if (ready) {
 145         /* Linux alters the tv struct... but it shouldn't matter here ...
 146          * as we're going to be a little bit out anyway as we've just eaten
 147          * more than a couple of cpu cycles above */
 148             ready = select ((SELECT_TYPE_ARG1) maxfd + 1, SELECT_TYPE_ARG234 &rset,
 149                             SELECT_TYPE_ARG234 &wset, SELECT_TYPE_ARG234 &xset,
 150                             SELECT_TYPE_ARG5 (timeout == -1 ? NULL : &tv));
 151         }
 152     }
 153
 154 #ifdef OS_IS_WIN32
 155     errno = WSAGetLastError();
 156 #endif
 157
 158     if (ready > 0) {
 159         ready = 0;
 160         for (f = fds; f < &fds[nfds]; ++f) {
 161             f->revents = 0;
 162             if (f->fd != -1) {
 163                 if (FD_ISSET (f->fd, &rset)) {
 164                     /* support for POLLHUP.  An hung up descriptor does not
 165                        increase the return value! */
 166                     if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
 167                         if (errno == ESHUTDOWN || errno == ECONNRESET ||
 168                             errno == ECONNABORTED || errno == ENETRESET) {
 169                             fprintf(stderr, "Hangup\n");
 170                             f->revents |= POLLHUP;
 171                         }
 172                     }
 173
 174                     if (f->revents == 0)
 175                         f->revents |= POLLIN;
 176                 }
 177                 if (FD_ISSET (f->fd, &wset))
 178                     f->revents |= POLLOUT;
 179                 if (FD_ISSET (f->fd, &xset))
 180                     f->revents |= POLLPRI;
 181             }
 182             if (f->revents)
 183                 ready++;
 184         }
 185     }
 186
 187     return ready;
 188 }
 189
 190 #endif /* HAVE_SYS_POLL_H */