--- /dev/null
+/* $OpenBSD: poll.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
+
+/*
+ * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
+ * Copyright 2007-2012 Niels Provos and Nick Mathewson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "event2/event-config.h"
+
+#include <sys/types.h>
+#ifdef _EVENT_HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#include <sys/queue.h>
+#include <poll.h>
+#include <signal.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "event-internal.h"
+#include "evsignal-internal.h"
+#include "log-internal.h"
+#include "evmap-internal.h"
+#include "event2/thread.h"
+#include "evthread-internal.h"
+
+struct pollidx {
+ int idxplus1;
+};
+
+struct pollop {
+ int event_count; /* Highest number alloc */
+ int nfds; /* Highest number used */
+ int realloc_copy; /* True iff we must realloc
+ * event_set_copy */
+ struct pollfd *event_set;
+ struct pollfd *event_set_copy;
+};
+
+static void *poll_init(struct event_base *);
+static int poll_add(struct event_base *, int, short old, short events, void *_idx);
+static int poll_del(struct event_base *, int, short old, short events, void *_idx);
+static int poll_dispatch(struct event_base *, struct timeval *);
+static void poll_dealloc(struct event_base *);
+
+const struct eventop pollops = {
+ "poll",
+ poll_init,
+ poll_add,
+ poll_del,
+ poll_dispatch,
+ poll_dealloc,
+ 0, /* doesn't need_reinit */
+ EV_FEATURE_FDS,
+ sizeof(struct pollidx),
+};
+
+static void *
+poll_init(struct event_base *base)
+{
+ struct pollop *pollop;
+
+ if (!(pollop = mm_calloc(1, sizeof(struct pollop))))
+ return (NULL);
+
+ evsig_init(base);
+
+ return (pollop);
+}
+
+#ifdef CHECK_INVARIANTS
+static void
+poll_check_ok(struct pollop *pop)
+{
+ int i, idx;
+ struct event *ev;
+
+ for (i = 0; i < pop->fd_count; ++i) {
+ idx = pop->idxplus1_by_fd[i]-1;
+ if (idx < 0)
+ continue;
+ EVUTIL_ASSERT(pop->event_set[idx].fd == i);
+ }
+ for (i = 0; i < pop->nfds; ++i) {
+ struct pollfd *pfd = &pop->event_set[i];
+ EVUTIL_ASSERT(pop->idxplus1_by_fd[pfd->fd] == i+1);
+ }
+}
+#else
+#define poll_check_ok(pop)
+#endif
+
+static int
+poll_dispatch(struct event_base *base, struct timeval *tv)
+{
+ int res, i, j, nfds;
+ long msec = -1;
+ struct pollop *pop = base->evbase;
+ struct pollfd *event_set;
+
+ poll_check_ok(pop);
+
+ nfds = pop->nfds;
+
+#ifndef _EVENT_DISABLE_THREAD_SUPPORT
+ if (base->th_base_lock) {
+ /* If we're using this backend in a multithreaded setting,
+ * then we need to work on a copy of event_set, so that we can
+ * let other threads modify the main event_set while we're
+ * polling. If we're not multithreaded, then we'll skip the
+ * copy step here to save memory and time. */
+ if (pop->realloc_copy) {
+ struct pollfd *tmp = mm_realloc(pop->event_set_copy,
+ pop->event_count * sizeof(struct pollfd));
+ if (tmp == NULL) {
+ event_warn("realloc");
+ return -1;
+ }
+ pop->event_set_copy = tmp;
+ pop->realloc_copy = 0;
+ }
+ memcpy(pop->event_set_copy, pop->event_set,
+ sizeof(struct pollfd)*nfds);
+ event_set = pop->event_set_copy;
+ } else {
+ event_set = pop->event_set;
+ }
+#else
+ event_set = pop->event_set;
+#endif
+
+ if (tv != NULL) {
+ msec = evutil_tv_to_msec(tv);
+ if (msec < 0 || msec > INT_MAX)
+ msec = INT_MAX;
+ }
+
+ EVBASE_RELEASE_LOCK(base, th_base_lock);
+
+ res = poll(event_set, nfds, msec);
+
+ EVBASE_ACQUIRE_LOCK(base, th_base_lock);
+
+ if (res == -1) {
+ if (errno != EINTR) {
+ event_warn("poll");
+ return (-1);
+ }
+
+ return (0);
+ }
+
+ event_debug(("%s: poll reports %d", __func__, res));
+
+ if (res == 0 || nfds == 0)
+ return (0);
+
+ i = random() % nfds;
+ for (j = 0; j < nfds; j++) {
+ int what;
+ if (++i == nfds)
+ i = 0;
+ what = event_set[i].revents;
+ if (!what)
+ continue;
+
+ res = 0;
+
+ /* If the file gets closed notify */
+ if (what & (POLLHUP|POLLERR))
+ what |= POLLIN|POLLOUT;
+ if (what & POLLIN)
+ res |= EV_READ;
+ if (what & POLLOUT)
+ res |= EV_WRITE;
+ if (res == 0)
+ continue;
+
+ evmap_io_active(base, event_set[i].fd, res);
+ }
+
+ return (0);
+}
+
+static int
+poll_add(struct event_base *base, int fd, short old, short events, void *_idx)
+{
+ struct pollop *pop = base->evbase;
+ struct pollfd *pfd = NULL;
+ struct pollidx *idx = _idx;
+ int i;
+
+ EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
+ if (!(events & (EV_READ|EV_WRITE)))
+ return (0);
+
+ poll_check_ok(pop);
+ if (pop->nfds + 1 >= pop->event_count) {
+ struct pollfd *tmp_event_set;
+ int tmp_event_count;
+
+ if (pop->event_count < 32)
+ tmp_event_count = 32;
+ else
+ tmp_event_count = pop->event_count * 2;
+
+ /* We need more file descriptors */
+ tmp_event_set = mm_realloc(pop->event_set,
+ tmp_event_count * sizeof(struct pollfd));
+ if (tmp_event_set == NULL) {
+ event_warn("realloc");
+ return (-1);
+ }
+ pop->event_set = tmp_event_set;
+
+ pop->event_count = tmp_event_count;
+ pop->realloc_copy = 1;
+ }
+
+ i = idx->idxplus1 - 1;
+
+ if (i >= 0) {
+ pfd = &pop->event_set[i];
+ } else {
+ i = pop->nfds++;
+ pfd = &pop->event_set[i];
+ pfd->events = 0;
+ pfd->fd = fd;
+ idx->idxplus1 = i + 1;
+ }
+
+ pfd->revents = 0;
+ if (events & EV_WRITE)
+ pfd->events |= POLLOUT;
+ if (events & EV_READ)
+ pfd->events |= POLLIN;
+ poll_check_ok(pop);
+
+ return (0);
+}
+
+/*
+ * Nothing to be done here.
+ */
+
+static int
+poll_del(struct event_base *base, int fd, short old, short events, void *_idx)
+{
+ struct pollop *pop = base->evbase;
+ struct pollfd *pfd = NULL;
+ struct pollidx *idx = _idx;
+ int i;
+
+ EVUTIL_ASSERT((events & EV_SIGNAL) == 0);
+ if (!(events & (EV_READ|EV_WRITE)))
+ return (0);
+
+ poll_check_ok(pop);
+ i = idx->idxplus1 - 1;
+ if (i < 0)
+ return (-1);
+
+ /* Do we still want to read or write? */
+ pfd = &pop->event_set[i];
+ if (events & EV_READ)
+ pfd->events &= ~POLLIN;
+ if (events & EV_WRITE)
+ pfd->events &= ~POLLOUT;
+ poll_check_ok(pop);
+ if (pfd->events)
+ /* Another event cares about that fd. */
+ return (0);
+
+ /* Okay, so we aren't interested in that fd anymore. */
+ idx->idxplus1 = 0;
+
+ --pop->nfds;
+ if (i != pop->nfds) {
+ /*
+ * Shift the last pollfd down into the now-unoccupied
+ * position.
+ */
+ memcpy(&pop->event_set[i], &pop->event_set[pop->nfds],
+ sizeof(struct pollfd));
+ idx = evmap_io_get_fdinfo(&base->io, pop->event_set[i].fd);
+ EVUTIL_ASSERT(idx);
+ EVUTIL_ASSERT(idx->idxplus1 == pop->nfds + 1);
+ idx->idxplus1 = i + 1;
+ }
+
+ poll_check_ok(pop);
+ return (0);
+}
+
+static void
+poll_dealloc(struct event_base *base)
+{
+ struct pollop *pop = base->evbase;
+
+ evsig_dealloc(base);
+ if (pop->event_set)
+ mm_free(pop->event_set);
+ if (pop->event_set_copy)
+ mm_free(pop->event_set_copy);
+
+ memset(pop, 0, sizeof(struct pollop));
+ mm_free(pop);
+}
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