1 /*****************************************************************************
2 * poll.c: I/O event multiplexing
3 *****************************************************************************
4 * Copyright © 2007 Rémi Denis-Courmont
7 * Author: Rémi Denis-Courmont
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
22 *****************************************************************************/
28 #include <vlc_common.h>
30 #include <vlc_network.h>
38 int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
40 struct timespec tsbuf, *ts;
46 div_t d = div (timeout, 1000);
47 tsbuf.tv_sec = d.quot;
48 tsbuf.tv_nsec = d.rem * 1000000;
54 pthread_sigmask (SIG_BLOCK, NULL, &set);
55 sigdelset (&set, SIGRTMIN);
57 canc = vlc_savecancel ();
58 ret = ppoll (fds, nfds, ts, &set);
59 vlc_restorecancel (canc);
65 #elif defined (HAVE_POLL)
68 int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
70 (void)fds; (void)nfds; (void)timeout;
79 int vlc_poll (struct pollfd *fds, unsigned nfds, int timeout)
81 size_t setsize = sizeof (fd_set) + (nfds - FD_SETSIZE) * sizeof (SOCKET);
82 fd_set *rdset = malloc (setsize);
83 fd_set *wrset = malloc (setsize);
84 fd_set *exset = malloc (setsize);
85 struct timeval tv = { 0, 0 };
88 if (unlikely(rdset == NULL || wrset == NULL || exset == NULL))
104 for (unsigned i = 0; i < nfds; i++)
110 /* With POSIX, FD_SET & FD_ISSET are not defined if fd is negative or
111 * bigger or equal than FD_SETSIZE. That is one of the reasons why VLC
112 * uses poll() rather than select(). Most POSIX systems implement
113 * fd_set has a bit field with no sanity checks. This is especially bad
114 * on systems (such as BSD) that have no process open files limit by
115 * default, such that it is quite feasible to get fd >= FD_SETSIZE.
116 * The next instructions will result in a buffer overflow if run on
117 * a POSIX system, and the later FD_ISSET would perform an undefined
120 * With Winsock, fd_set is a table of integers. This is awfully slow.
121 * However, FD_SET and FD_ISSET silently and safely discard excess
122 * entries. Here, overflow cannot happen anyway: fd_set of adequate
123 * size are allocated.
124 * Note that Vista has a much nicer WSAPoll(), but Mingw does not
127 if (fds[i].events & POLLIN)
128 FD_SET ((SOCKET)fd, rdset);
129 if (fds[i].events & POLLOUT)
130 FD_SET ((SOCKET)fd, wrset);
131 if (fds[i].events & POLLPRI)
132 FD_SET ((SOCKET)fd, exset);
135 #ifndef HAVE_ALERTABLE_SELECT
136 # warning FIXME! Fix cancellation and remove this crap.
137 if ((timeout < 0) || (timeout > 50))
146 div_t d = div (timeout, 1000);
148 tv.tv_usec = d.rem * 1000;
151 val = select (val + 1, rdset, wrset, exset,
152 /*(timeout >= 0) ?*/ &tv /*: NULL*/);
154 #ifndef HAVE_ALERTABLE_SELECT
158 timeout -= (timeout > 50) ? 50 : timeout;
167 for (unsigned i = 0; i < nfds; i++)
170 fds[i].revents = (FD_ISSET (fd, rdset) ? POLLIN : 0)
171 | (FD_ISSET (fd, wrset) ? POLLOUT : 0)
172 | (FD_ISSET (fd, exset) ? POLLPRI : 0);
181 # error poll() not implemented!