summaryrefslogtreecommitdiff
path: root/libevent/select.c
diff options
context:
space:
mode:
Diffstat (limited to 'libevent/select.c')
-rw-r--r--libevent/select.c356
1 files changed, 356 insertions, 0 deletions
diff --git a/libevent/select.c b/libevent/select.c
new file mode 100644
index 00000000000..ca6639fd829
--- /dev/null
+++ b/libevent/select.c
@@ -0,0 +1,356 @@
+/* $OpenBSD: select.c,v 1.2 2002/06/25 15:50:15 mickey Exp $ */
+
+/*
+ * Copyright 2000-2002 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * 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.
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/types.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#else
+#include <sys/_time.h>
+#endif
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+#include <sys/queue.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#ifdef CHECK_INVARIANTS
+#include <assert.h>
+#endif
+
+#include "event.h"
+#include "event-internal.h"
+#include "evsignal.h"
+#include "log.h"
+
+#ifndef howmany
+#define howmany(x, y) (((x)+((y)-1))/(y))
+#endif
+
+struct selectop {
+ int event_fds; /* Highest fd in fd set */
+ int event_fdsz;
+ fd_set *event_readset_in;
+ fd_set *event_writeset_in;
+ fd_set *event_readset_out;
+ fd_set *event_writeset_out;
+ struct event **event_r_by_fd;
+ struct event **event_w_by_fd;
+};
+
+static void *select_init (struct event_base *);
+static int select_add (void *, struct event *);
+static int select_del (void *, struct event *);
+static int select_dispatch (struct event_base *, void *, struct timeval *);
+static void select_dealloc (struct event_base *, void *);
+
+const struct eventop selectops = {
+ "select",
+ select_init,
+ select_add,
+ select_del,
+ select_dispatch,
+ select_dealloc,
+ 0
+};
+
+static int select_resize(struct selectop *sop, int fdsz);
+
+static void *
+select_init(struct event_base *base)
+{
+ struct selectop *sop;
+
+ /* Disable select when this environment variable is set */
+ if (getenv("EVENT_NOSELECT"))
+ return (NULL);
+
+ if (!(sop = calloc(1, sizeof(struct selectop))))
+ return (NULL);
+
+ select_resize(sop, howmany(32 + 1, NFDBITS)*sizeof(fd_mask));
+
+ evsignal_init(base);
+
+ return (sop);
+}
+
+#ifdef CHECK_INVARIANTS
+static void
+check_selectop(struct selectop *sop)
+{
+ int i;
+ for (i = 0; i <= sop->event_fds; ++i) {
+ if (FD_ISSET(i, sop->event_readset_in)) {
+ assert(sop->event_r_by_fd[i]);
+ assert(sop->event_r_by_fd[i]->ev_events & EV_READ);
+ assert(sop->event_r_by_fd[i]->ev_fd == i);
+ } else {
+ assert(! sop->event_r_by_fd[i]);
+ }
+ if (FD_ISSET(i, sop->event_writeset_in)) {
+ assert(sop->event_w_by_fd[i]);
+ assert(sop->event_w_by_fd[i]->ev_events & EV_WRITE);
+ assert(sop->event_w_by_fd[i]->ev_fd == i);
+ } else {
+ assert(! sop->event_w_by_fd[i]);
+ }
+ }
+
+}
+#else
+#define check_selectop(sop) do { (void) sop; } while (0)
+#endif
+
+static int
+select_dispatch(struct event_base *base, void *arg, struct timeval *tv)
+{
+ int res, i, j;
+ struct selectop *sop = arg;
+
+ check_selectop(sop);
+
+ memcpy(sop->event_readset_out, sop->event_readset_in,
+ sop->event_fdsz);
+ memcpy(sop->event_writeset_out, sop->event_writeset_in,
+ sop->event_fdsz);
+
+ res = select(sop->event_fds + 1, sop->event_readset_out,
+ sop->event_writeset_out, NULL, tv);
+
+ check_selectop(sop);
+
+ if (res == -1) {
+ if (errno != EINTR) {
+ event_warn("select");
+ return (-1);
+ }
+
+ evsignal_process(base);
+ return (0);
+ } else if (base->sig.evsignal_caught) {
+ evsignal_process(base);
+ }
+
+ event_debug(("%s: select reports %d", __func__, res));
+
+ check_selectop(sop);
+ i = random() % (sop->event_fds+1);
+ for (j = 0; j <= sop->event_fds; ++j) {
+ struct event *r_ev = NULL, *w_ev = NULL;
+ if (++i >= sop->event_fds+1)
+ i = 0;
+
+ res = 0;
+ if (FD_ISSET(i, sop->event_readset_out)) {
+ r_ev = sop->event_r_by_fd[i];
+ res |= EV_READ;
+ }
+ if (FD_ISSET(i, sop->event_writeset_out)) {
+ w_ev = sop->event_w_by_fd[i];
+ res |= EV_WRITE;
+ }
+ if (r_ev && (res & r_ev->ev_events)) {
+ event_active(r_ev, res & r_ev->ev_events, 1);
+ }
+ if (w_ev && w_ev != r_ev && (res & w_ev->ev_events)) {
+ event_active(w_ev, res & w_ev->ev_events, 1);
+ }
+ }
+ check_selectop(sop);
+
+ return (0);
+}
+
+
+static int
+select_resize(struct selectop *sop, int fdsz)
+{
+ int n_events, n_events_old;
+
+ fd_set *readset_in = NULL;
+ fd_set *writeset_in = NULL;
+ fd_set *readset_out = NULL;
+ fd_set *writeset_out = NULL;
+ struct event **r_by_fd = NULL;
+ struct event **w_by_fd = NULL;
+
+ n_events = (fdsz/sizeof(fd_mask)) * NFDBITS;
+ n_events_old = (sop->event_fdsz/sizeof(fd_mask)) * NFDBITS;
+
+ if (sop->event_readset_in)
+ check_selectop(sop);
+
+ if ((readset_in = realloc(sop->event_readset_in, fdsz)) == NULL)
+ goto error;
+ sop->event_readset_in = readset_in;
+ if ((readset_out = realloc(sop->event_readset_out, fdsz)) == NULL)
+ goto error;
+ sop->event_readset_out = readset_out;
+ if ((writeset_in = realloc(sop->event_writeset_in, fdsz)) == NULL)
+ goto error;
+ sop->event_writeset_in = writeset_in;
+ if ((writeset_out = realloc(sop->event_writeset_out, fdsz)) == NULL)
+ goto error;
+ sop->event_writeset_out = writeset_out;
+ if ((r_by_fd = realloc(sop->event_r_by_fd,
+ n_events*sizeof(struct event*))) == NULL)
+ goto error;
+ sop->event_r_by_fd = r_by_fd;
+ if ((w_by_fd = realloc(sop->event_w_by_fd,
+ n_events * sizeof(struct event*))) == NULL)
+ goto error;
+ sop->event_w_by_fd = w_by_fd;
+
+ memset((char *)sop->event_readset_in + sop->event_fdsz, 0,
+ fdsz - sop->event_fdsz);
+ memset((char *)sop->event_writeset_in + sop->event_fdsz, 0,
+ fdsz - sop->event_fdsz);
+ memset(sop->event_r_by_fd + n_events_old, 0,
+ (n_events-n_events_old) * sizeof(struct event*));
+ memset(sop->event_w_by_fd + n_events_old, 0,
+ (n_events-n_events_old) * sizeof(struct event*));
+
+ sop->event_fdsz = fdsz;
+ check_selectop(sop);
+
+ return (0);
+
+ error:
+ event_warn("malloc");
+ return (-1);
+}
+
+
+static int
+select_add(void *arg, struct event *ev)
+{
+ struct selectop *sop = arg;
+
+ if (ev->ev_events & EV_SIGNAL)
+ return (evsignal_add(ev));
+
+ check_selectop(sop);
+ /*
+ * Keep track of the highest fd, so that we can calculate the size
+ * of the fd_sets for select(2)
+ */
+ if (sop->event_fds < ev->ev_fd) {
+ int fdsz = sop->event_fdsz;
+
+ if (fdsz < sizeof(fd_mask))
+ fdsz = sizeof(fd_mask);
+
+ while (fdsz <
+ (howmany(ev->ev_fd + 1, NFDBITS) * sizeof(fd_mask)))
+ fdsz *= 2;
+
+ if (fdsz != sop->event_fdsz) {
+ if (select_resize(sop, fdsz)) {
+ check_selectop(sop);
+ return (-1);
+ }
+ }
+
+ sop->event_fds = ev->ev_fd;
+ }
+
+ if (ev->ev_events & EV_READ) {
+ FD_SET(ev->ev_fd, sop->event_readset_in);
+ sop->event_r_by_fd[ev->ev_fd] = ev;
+ }
+ if (ev->ev_events & EV_WRITE) {
+ FD_SET(ev->ev_fd, sop->event_writeset_in);
+ sop->event_w_by_fd[ev->ev_fd] = ev;
+ }
+ check_selectop(sop);
+
+ return (0);
+}
+
+/*
+ * Nothing to be done here.
+ */
+
+static int
+select_del(void *arg, struct event *ev)
+{
+ struct selectop *sop = arg;
+
+ check_selectop(sop);
+ if (ev->ev_events & EV_SIGNAL)
+ return (evsignal_del(ev));
+
+ if (sop->event_fds < ev->ev_fd) {
+ check_selectop(sop);
+ return (0);
+ }
+
+ if (ev->ev_events & EV_READ) {
+ FD_CLR(ev->ev_fd, sop->event_readset_in);
+ sop->event_r_by_fd[ev->ev_fd] = NULL;
+ }
+
+ if (ev->ev_events & EV_WRITE) {
+ FD_CLR(ev->ev_fd, sop->event_writeset_in);
+ sop->event_w_by_fd[ev->ev_fd] = NULL;
+ }
+
+ check_selectop(sop);
+ return (0);
+}
+
+static void
+select_dealloc(struct event_base *base, void *arg)
+{
+ struct selectop *sop = arg;
+
+ evsignal_dealloc(base);
+ if (sop->event_readset_in)
+ free(sop->event_readset_in);
+ if (sop->event_writeset_in)
+ free(sop->event_writeset_in);
+ if (sop->event_readset_out)
+ free(sop->event_readset_out);
+ if (sop->event_writeset_out)
+ free(sop->event_writeset_out);
+ if (sop->event_r_by_fd)
+ free(sop->event_r_by_fd);
+ if (sop->event_w_by_fd)
+ free(sop->event_w_by_fd);
+
+ memset(sop, 0, sizeof(struct selectop));
+ free(sop);
+}