tor/src/common/fakepoll.c

/*
 * fakepoll.c
 *
 * On systems where 'poll' doesn't exist, fake it with 'select'.
 *
 * Nick Mathewson <nickm@freehaven.net>
 */

#include "orconfig.h"
#include "fakepoll.h"

#ifdef USE_FAKE_POLL
#include <sys/types.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#if _MSC_VER > 1300
#include <winsock2.h>
#include <ws2tcpip.h>
#elif defined(_MSC_VER)
#include <winsock.h>
#endif

#include "util.h"

int
poll(struct pollfd *ufds, unsigned int nfds, int timeout)
{
	unsigned int idx, maxfd, fd;
	int r;
#ifdef MS_WINDOWS
        int any_fds_set = 0;
#endif
	fd_set readfds, writefds, exceptfds;
#ifdef USING_FAKE_TIMEVAL
#undef timeval
#undef tv_sec
#undef tv_usec
#endif
	struct timeval _timeout;
	_timeout.tv_sec = timeout/1000;
	_timeout.tv_usec = (timeout%1000)*1000;
	FD_ZERO(&readfds);
	FD_ZERO(&writefds);
	FD_ZERO(&exceptfds);

	maxfd = -1;
	for (idx = 0; idx < nfds; ++idx) {
		fd = ufds[idx].fd;
                if (ufds[idx].events) {
                        if (fd > maxfd) 
                                maxfd = fd;
#ifdef MS_WINDOWS
                        any_fds_set = 1;
#endif
                }
		if (ufds[idx].events & POLLIN)
			FD_SET(fd, &readfds);
		if (ufds[idx].events & POLLOUT)
			FD_SET(fd, &writefds);
		if (ufds[idx].events & POLLERR)
			FD_SET(fd, &exceptfds);
	}
#ifdef MS_WINDOWS
        if (!any_fds_set) {
                Sleep(timeout);
                return 0;
        }
#endif
	r = select(maxfd+1, &readfds, &writefds, &exceptfds, 
		   timeout == -1 ? NULL : &_timeout);
	if (r <= 0)
		return r;
	r = 0;
	for (idx = 0; idx < nfds; ++idx) {
		fd = ufds[idx].fd;
		ufds[idx].revents = 0;
		if (FD_ISSET(fd, &readfds))
			ufds[idx].revents |= POLLIN;
		if (FD_ISSET(fd, &writefds))
			ufds[idx].revents |= POLLOUT;
		if (FD_ISSET(fd, &exceptfds))
			ufds[idx].revents |= POLLERR;
		if (ufds[idx].revents)
			++r;
	}
	return r;
}
#endif