/*      $NetBSD: regress_et.c,v 1.4 2021/04/07 03:36:48 christos Exp $  */

/*
* Copyright (c) 2009-2012 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 "../util-internal.h"
#include "event2/event-config.h"
#include <sys/cdefs.h>
__RCSID("$NetBSD: regress_et.c,v 1.4 2021/04/07 03:36:48 christos Exp $");

#ifdef _WIN32
#include <winsock2.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#ifdef EVENT__HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifndef _WIN32
#include <sys/time.h>
#include <unistd.h>
#endif
#include <errno.h>

#include "event2/event.h"
#include "event2/util.h"

#include "regress.h"

static int was_et = 0;

static int base_supports_et(struct event_base *base)
{
       return
               (!strcmp(event_base_get_method(base), "epoll") ||
               !strcmp(event_base_get_method(base), "epoll (with changelist)") ||
               !strcmp(event_base_get_method(base), "kqueue"));
}

static void
read_cb(evutil_socket_t fd, short event, void *arg)
{
       char buf;
       int len;

       len = recv(fd, &buf, sizeof(buf), 0);

       called++;
       if (event & EV_ET)
               was_et = 1;

       if (!len)
               event_del(arg);
}

static void
test_edgetriggered(void *data_)
{
       struct basic_test_data *data = data_;
       struct event_base *base = data->base;
       evutil_socket_t *xpair = data->pair;
       struct event *ev = NULL;
       const char *test = "test string";
       int supports_et;

       /* On Linux 3.2.1 (at least, as patched by Fedora and tested by Nick),
        * doing a "recv" on an AF_UNIX socket resets the readability of the
        * socket, even though there is no state change, so we don't actually
        * get edge-triggered behavior.  Yuck!  Linux 3.1.9 didn't have this
        * problem.
        */

       called = was_et = 0;

       tt_int_op(send(xpair[0], test, (int)strlen(test)+1, 0), >, 0);
       tt_int_op(shutdown(xpair[0], EVUTIL_SHUT_WR), ==, 0);

       supports_et = base_supports_et(base);
       TT_BLATHER(("Checking for edge-triggered events with %s, which should %s"
                               "support edge-triggering", event_base_get_method(base),
                               supports_et?"":"not "));

       /* Initialize one event */
       ev = event_new(base, xpair[1], EV_READ|EV_ET|EV_PERSIST, read_cb, &ev);
       tt_assert(ev != NULL);
       tt_int_op(event_add(ev, NULL), ==, 0);

       /* We're going to call the dispatch function twice.  The first invocation
        * will read a single byte from xpair[1] in either case.  If we're edge
        * triggered, we'll only see the event once (since we only see transitions
        * from no data to data), so the second invocation of event_base_loop will
        * do nothing.  If we're level triggered, the second invocation of
        * event_base_loop will also activate the event (because there's still
        * data to read). */
       tt_int_op(event_base_loop(base,EVLOOP_NONBLOCK|EVLOOP_ONCE), ==, 0);
       tt_int_op(event_base_loop(base,EVLOOP_NONBLOCK|EVLOOP_ONCE), ==, 0);

       if (supports_et) {
               tt_int_op(called, ==, 1);
               tt_assert(was_et);
       } else {
               tt_int_op(called, ==, 2);
               tt_assert(!was_et);
       }

end:
       if (ev) {
               event_del(ev);
               event_free(ev);
       }
}

static void
test_edgetriggered_mix_error(void *data_)
{
       struct basic_test_data *data = data_;
       struct event_base *base = NULL;
       struct event *ev_et=NULL, *ev_lt=NULL;

#ifdef EVENT__DISABLE_DEBUG_MODE
       if (1)
               tt_skip();
#endif

       if (!libevent_tests_running_in_debug_mode)
               event_enable_debug_mode();

       base = event_base_new();

       /* try mixing edge-triggered and level-triggered to make sure it fails*/
       ev_et = event_new(base, data->pair[0], EV_READ|EV_ET, read_cb, ev_et);
       tt_assert(ev_et);
       ev_lt = event_new(base, data->pair[0], EV_READ, read_cb, ev_lt);
       tt_assert(ev_lt);

       /* Add edge-triggered, then level-triggered.  Get an error. */
       tt_int_op(0, ==, event_add(ev_et, NULL));
       tt_int_op(-1, ==, event_add(ev_lt, NULL));
       tt_int_op(EV_READ, ==, event_pending(ev_et, EV_READ, NULL));
       tt_int_op(0, ==, event_pending(ev_lt, EV_READ, NULL));

       tt_int_op(0, ==, event_del(ev_et));
       /* Add level-triggered, then edge-triggered.  Get an error. */
       tt_int_op(0, ==, event_add(ev_lt, NULL));
       tt_int_op(-1, ==, event_add(ev_et, NULL));
       tt_int_op(EV_READ, ==, event_pending(ev_lt, EV_READ, NULL));
       tt_int_op(0, ==, event_pending(ev_et, EV_READ, NULL));

end:
       if (ev_et)
               event_free(ev_et);
       if (ev_lt)
               event_free(ev_lt);
       if (base)
               event_base_free(base);
}

static int read_notification_count;
static int last_read_notification_was_et;
static void
read_notification_cb(evutil_socket_t fd, short event, void *arg)
{
       read_notification_count++;
       last_read_notification_was_et = (event & EV_ET);
}

static int write_notification_count;
static int last_write_notification_was_et;
static void
write_notification_cb(evutil_socket_t fd, short event, void *arg)
{
       write_notification_count++;
       last_write_notification_was_et = (event & EV_ET);
}

/* After two or more events have been registered for the same
* file descriptor using EV_ET, if one of the events is
* deleted, then the epoll_ctl() call issued by libevent drops
* the EPOLLET flag resulting in level triggered
* notifications.
*/
static void
test_edge_triggered_multiple_events(void *data_)
{
       struct basic_test_data *data = data_;
       struct event *read_ev = NULL;
       struct event *write_ev = NULL;
       const char c = 'A';
       struct event_base *base = data->base;
       evutil_socket_t *xpair = data->pair;

       if (!base_supports_et(base)) {
               tt_skip();
               return;
       }

       read_notification_count = 0;
       last_read_notification_was_et = 0;
       write_notification_count = 0;
       last_write_notification_was_et = 0;

       /* Make xpair[1] readable */
       tt_int_op(send(xpair[0], &c, 1, 0), >, 0);

       read_ev = event_new(base, xpair[1], EV_READ|EV_ET|EV_PERSIST,
               read_notification_cb, NULL);
       write_ev = event_new(base, xpair[1], EV_WRITE|EV_ET|EV_PERSIST,
               write_notification_cb, NULL);

       event_add(read_ev, NULL);
       event_add(write_ev, NULL);
       event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
       event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);

       tt_assert(last_read_notification_was_et);
       tt_int_op(read_notification_count, ==, 1);
       tt_assert(last_write_notification_was_et);
       tt_int_op(write_notification_count, ==, 1);

       event_del(read_ev);

       /* trigger acitivity second time for the backend that can have multiple
        * events for one fd (like kqueue) */
       close(xpair[0]);
       xpair[0] = -1;

       /* Verify that we are still edge-triggered for write notifications */
       event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
       event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
       tt_assert(last_write_notification_was_et);
       tt_int_op(write_notification_count, ==, 2);

end:
       if (read_ev)
               event_free(read_ev);
       if (write_ev)
               event_free(write_ev);
}

struct testcase_t edgetriggered_testcases[] = {
       { "et", test_edgetriggered,
         TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR, &basic_setup, NULL },
       { "et_mix_error", test_edgetriggered_mix_error,
         TT_FORK|TT_NEED_SOCKETPAIR|TT_NO_LOGS, &basic_setup, NULL },
       { "et_multiple_events", test_edge_triggered_multiple_events,
         TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR, &basic_setup, NULL },
       END_OF_TESTCASES
};

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.