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, see <http://www.gnu.org/licenses/>.
19***/
20
21/***
22   Based on work for the GNU C Library.
23   Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
24***/
25
26/* Poll the file descriptors described by the NFDS structures starting at
27   FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
28   an event to occur; if TIMEOUT is -1, block until an event occurs.
29   Returns the number of file descriptors with events, zero if timed out,
30   or -1 for errors.  */
31
32#ifdef HAVE_CONFIG_H
33#include <config.h>
34#endif
35
36#ifdef HAVE_SYS_IOCTL_H
37#include <sys/ioctl.h>
38#endif
39
40#include <errno.h>
41#include <fcntl.h>
42
43#ifdef HAVE_SYS_SELECT_H
44#include <sys/select.h>
45#endif
46
47#include <pulsecore/socket.h>
48#include <pulsecore/core-util.h>
49#include <pulse/util.h>
50
51#include "poll.h"
52
53/* Mac OSX fails to implement poll() in a working way since 10.4. IOW, for
54 * several years. We need to enable a dirty workaround and emulate that call
55 * with select(), just like for Windows. sic! */
56
57#if !defined(HAVE_POLL_H) || defined(OS_IS_DARWIN)
58
59int pa_poll (struct pollfd *fds, unsigned long int nfds, int timeout) {
60    struct timeval tv;
61    fd_set rset, wset, xset;
62    struct pollfd *f;
63    int ready;
64    int maxfd = 0;
65#ifdef OS_IS_WIN32
66    char data[64];
67#endif
68
69    FD_ZERO (&rset);
70    FD_ZERO (&wset);
71    FD_ZERO (&xset);
72
73    if (nfds == 0) {
74        if (timeout >= 0) {
75            pa_msleep(timeout);
76            return 0;
77        }
78
79#ifdef OS_IS_WIN32
80        /*
81         * Windows does not support signals properly so waiting for them would
82         * mean a deadlock.
83         */
84        pa_msleep(100);
85        return 0;
86#else
87        return select(0, NULL, NULL, NULL, NULL);
88#endif
89    }
90
91    for (f = fds; f < &fds[nfds]; ++f) {
92        if (f->fd != -1) {
93            if (f->events & POLLIN)
94                FD_SET (f->fd, &rset);
95            if (f->events & POLLOUT)
96                FD_SET (f->fd, &wset);
97            if (f->events & POLLPRI)
98                FD_SET (f->fd, &xset);
99            if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
100                maxfd = f->fd;
101        }
102    }
103
104    tv.tv_sec = timeout / 1000;
105    tv.tv_usec = (timeout % 1000) * 1000;
106
107    ready = select(maxfd + 1, &rset, &wset, &xset, (timeout == -1 ? NULL : &tv));
108
109    if ((ready == -1) && (errno == EBADF)) {
110        ready = 0;
111        maxfd = -1;
112
113#ifdef OS_IS_WIN32
114        /*
115         * Windows has no fcntl(), so we have to trick around with more
116         * select() calls to find out what went wrong
117         */
118
119        FD_ZERO (&rset);
120        FD_ZERO (&wset);
121        FD_ZERO (&xset);
122
123        for (f = fds; f < &fds[nfds]; ++f) {
124            if (f->fd != -1) {
125                fd_set sngl_rset, sngl_wset, sngl_xset;
126
127                FD_ZERO (&sngl_rset);
128                FD_ZERO (&sngl_wset);
129                FD_ZERO (&sngl_xset);
130
131                if (f->events & POLLIN)
132                    FD_SET (f->fd, &sngl_rset);
133                if (f->events & POLLOUT)
134                    FD_SET (f->fd, &sngl_wset);
135                if (f->events & POLLPRI)
136                    FD_SET (f->fd, &sngl_xset);
137                if (f->events & (POLLIN|POLLOUT|POLLPRI)) {
138                    struct timeval singl_tv;
139
140                    singl_tv.tv_sec = 0;
141                    singl_tv.tv_usec = 0;
142
143                    if (select(f->fd, &rset, &wset, &xset, &singl_tv) != -1) {
144                        if (f->events & POLLIN)
145                            FD_SET (f->fd, &rset);
146                        if (f->events & POLLOUT)
147                            FD_SET (f->fd, &wset);
148                        if (f->events & POLLPRI)
149                            FD_SET (f->fd, &xset);
150                        if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI)))
151                            maxfd = f->fd;
152                        ++ready;
153                    } else if (errno == EBADF)
154                        f->revents |= POLLNVAL;
155                }
156            }
157        }
158
159#else /* !OS_IS_WIN32 */
160
161        for (f = fds; f < &fds[nfds]; f++)
162            if (f->fd != -1) {
163                /* use fcntl() to find out whether the descriptor is valid */
164                if (fcntl(f->fd, F_GETFL) != -1) {
165                    if (f->fd > maxfd && (f->events & (POLLIN|POLLOUT|POLLPRI))) {
166                        maxfd = f->fd;
167                        ready++;
168                    }
169                } else {
170                    FD_CLR(f->fd, &rset);
171                    FD_CLR(f->fd, &wset);
172                    FD_CLR(f->fd, &xset);
173                }
174            }
175
176#endif
177
178        if (ready) {
179        /* Linux alters the tv struct... but it shouldn't matter here ...
180         * as we're going to be a little bit out anyway as we've just eaten
181         * more than a couple of cpu cycles above */
182            ready = select(maxfd + 1, &rset, &wset, &xset, (timeout == -1 ? NULL : &tv));
183        }
184    }
185
186#ifdef OS_IS_WIN32
187    errno = WSAGetLastError();
188#endif
189
190    if (ready > 0) {
191        ready = 0;
192        for (f = fds; f < &fds[nfds]; ++f) {
193            f->revents = 0;
194            if (f->fd != -1) {
195                if (FD_ISSET (f->fd, &rset)) {
196                    /* support for POLLHUP.  An hung up descriptor does not
197                       increase the return value! */
198#ifdef OS_IS_DARWIN
199                    /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK
200                     * for some kinds of descriptors.  Detect if this descriptor is a
201                     * connected socket, a server socket, or something else using a
202                     * 0-byte recv, and use ioctl(2) to detect POLLHUP.  */
203                    int r = recv(f->fd, NULL, 0, MSG_PEEK);
204                    if (r == 0 || (r < 0 && errno == ENOTSOCK))
205                        ioctl(f->fd, FIONREAD, &r);
206
207                    if (r == 0)
208                        f->revents |= POLLHUP;
209#else /* !OS_IS_DARWIN */
210                    if (recv (f->fd, data, 64, MSG_PEEK) == -1) {
211                        if (errno == ESHUTDOWN || errno == ECONNRESET ||
212                            errno == ECONNABORTED || errno == ENETRESET) {
213                            fprintf(stderr, "Hangup\n");
214                            f->revents |= POLLHUP;
215                        }
216                    }
217#endif
218
219                    if (f->revents == 0)
220                        f->revents |= POLLIN;
221                }
222                if (FD_ISSET (f->fd, &wset))
223                    f->revents |= POLLOUT;
224                if (FD_ISSET (f->fd, &xset))
225                    f->revents |= POLLPRI;
226            }
227            if (f->revents)
228                ready++;
229        }
230    }
231
232    return ready;
233}
234
235#endif /* HAVE_SYS_POLL_H */
236