test/regress_et.c

   1 /*
   2  * Copyright (c) 2009-2012 Niels Provos and Nick Mathewson
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. The name of the author may not be used to endorse or promote products
  13  *    derived from this software without specific prior written permission.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26 #include "../util-internal.h"
  27 #include "event2/event-config.h"
  28
  29 #ifdef _WIN32
  30 #include <winsock2.h>
  31 #endif
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #ifdef EVENT__HAVE_SYS_SOCKET_H
  35 #include <sys/socket.h>
  36 #endif
  37 #include <fcntl.h>
  38 #include <stdlib.h>
  39 #include <stdio.h>
  40 #include <string.h>
  41 #ifndef _WIN32
  42 #include <sys/time.h>
  43 #include <unistd.h>
  44 #endif
  45 #include <errno.h>
  46
  47 #include "event2/event.h"
  48 #include "event2/util.h"
  49
  50 #include "regress.h"
  51
  52 static int was_et = 0;
  53
  54 static int base_supports_et(struct event_base *base)
  55 {
  56         return
  57                 (!strcmp(event_base_get_method(base), "epoll") ||
  58                 !strcmp(event_base_get_method(base), "epoll (with changelist)") ||
  59                 !strcmp(event_base_get_method(base), "kqueue"));
  60 }
  61
  62 static void
  63 read_cb(evutil_socket_t fd, short event, void *arg)
  64 {
  65         char buf;
  66         int len;
  67
  68         len = recv(fd, &buf, sizeof(buf), 0);
  69
  70         called++;
  71         if (event & EV_ET)
  72                 was_et = 1;
  73
  74         if (!len)
  75                 event_del(arg);
  76 }
  77
  78 static void
  79 test_edgetriggered(void *data_)
  80 {
  81         struct basic_test_data *data = data_;
  82         struct event_base *base = data->base;
  83         evutil_socket_t *pair = data->pair;
  84         struct event *ev = NULL;
  85         const char *test = "test string";
  86         int supports_et;
  87
  88         /* On Linux 3.2.1 (at least, as patched by Fedora and tested by Nick),
  89          * doing a "recv" on an AF_UNIX socket resets the readability of the
  90          * socket, even though there is no state change, so we don't actually
  91          * get edge-triggered behavior.  Yuck!  Linux 3.1.9 didn't have this
  92          * problem.
  93          */
  94
  95         called = was_et = 0;
  96
  97         tt_int_op(send(pair[0], test, (int)strlen(test)+1, 0), >, 0);
  98         tt_int_op(shutdown(pair[0], EVUTIL_SHUT_WR), ==, 0);
  99
 100         supports_et = base_supports_et(base);
 101         TT_BLATHER(("Checking for edge-triggered events with %s, which should %s"
 102                                 "support edge-triggering", event_base_get_method(base),
 103                                 supports_et?"":"not "));
 104
 105         /* Initalize one event */
 106         ev = event_new(base, pair[1], EV_READ|EV_ET|EV_PERSIST, read_cb, &ev);
 107         tt_assert(ev != NULL);
 108         tt_int_op(event_add(ev, NULL), ==, 0);
 109
 110         /* We're going to call the dispatch function twice.  The first invocation
 111          * will read a single byte from pair[1] in either case.  If we're edge
 112          * triggered, we'll only see the event once (since we only see transitions
 113          * from no data to data), so the second invocation of event_base_loop will
 114          * do nothing.  If we're level triggered, the second invocation of
 115          * event_base_loop will also activate the event (because there's still
 116          * data to read). */
 117         tt_int_op(event_base_loop(base,EVLOOP_NONBLOCK|EVLOOP_ONCE), ==, 0);
 118         tt_int_op(event_base_loop(base,EVLOOP_NONBLOCK|EVLOOP_ONCE), ==, 0);
 119
 120         if (supports_et) {
 121                 tt_int_op(called, ==, 1);
 122                 tt_assert(was_et);
 123         } else {
 124                 tt_int_op(called, ==, 2);
 125                 tt_assert(!was_et);
 126         }
 127
 128 end:
 129         if (ev) {
 130                 event_del(ev);
 131                 event_free(ev);
 132         }
 133 }
 134
 135 static void
 136 test_edgetriggered_mix_error(void *data_)
 137 {
 138         struct basic_test_data *data = data_;
 139         struct event_base *base = NULL;
 140         struct event *ev_et=NULL, *ev_lt=NULL;
 141
 142 #ifdef EVENT__DISABLE_DEBUG_MODE
 143         if (1)
 144                 tt_skip();
 145 #endif
 146
 147         if (!libevent_tests_running_in_debug_mode)
 148                 event_enable_debug_mode();
 149
 150         base = event_base_new();
 151
 152         /* try mixing edge-triggered and level-triggered to make sure it fails*/
 153         ev_et = event_new(base, data->pair[0], EV_READ|EV_ET, read_cb, ev_et);
 154         tt_assert(ev_et);
 155         ev_lt = event_new(base, data->pair[0], EV_READ, read_cb, ev_lt);
 156         tt_assert(ev_lt);
 157
 158         /* Add edge-triggered, then level-triggered.  Get an error. */
 159         tt_int_op(0, ==, event_add(ev_et, NULL));
 160         tt_int_op(-1, ==, event_add(ev_lt, NULL));
 161         tt_int_op(EV_READ, ==, event_pending(ev_et, EV_READ, NULL));
 162         tt_int_op(0, ==, event_pending(ev_lt, EV_READ, NULL));
 163
 164         tt_int_op(0, ==, event_del(ev_et));
 165         /* Add level-triggered, then edge-triggered.  Get an error. */
 166         tt_int_op(0, ==, event_add(ev_lt, NULL));
 167         tt_int_op(-1, ==, event_add(ev_et, NULL));
 168         tt_int_op(EV_READ, ==, event_pending(ev_lt, EV_READ, NULL));
 169         tt_int_op(0, ==, event_pending(ev_et, EV_READ, NULL));
 170
 171 end:
 172         if (ev_et)
 173                 event_free(ev_et);
 174         if (ev_lt)
 175                 event_free(ev_lt);
 176         if (base)
 177                 event_base_free(base);
 178 }
 179
 180 static int read_notification_count;
 181 static int last_read_notification_was_et;
 182 static void
 183 read_notification_cb(evutil_socket_t fd, short event, void *arg)
 184 {
 185         read_notification_count++;
 186         last_read_notification_was_et = (event & EV_ET);
 187 }
 188
 189 static int write_notification_count;
 190 static int last_write_notification_was_et;
 191 static void
 192 write_notification_cb(evutil_socket_t fd, short event, void *arg)
 193 {
 194         write_notification_count++;
 195         last_write_notification_was_et = (event & EV_ET);
 196 }
 197
 198 /* After two or more events have been registered for the same
 199  * file descriptor using EV_ET, if one of the events is
 200  * deleted, then the epoll_ctl() call issued by libevent drops
 201  * the EPOLLET flag resulting in level triggered
 202  * notifications.
 203  */
 204 static void
 205 test_edge_triggered_multiple_events(void *data_)
 206 {
 207         struct basic_test_data *data = data_;
 208         struct event *read_ev = NULL;
 209         struct event *write_ev = NULL;
 210         const char c = 'A';
 211         struct event_base *base = data->base;
 212         evutil_socket_t *pair = data->pair;
 213
 214         if (!base_supports_et(base)) {
 215                 tt_skip();
 216                 return;
 217         }
 218
 219         read_notification_count = 0;
 220         last_read_notification_was_et = 0;
 221         write_notification_count = 0;
 222         last_write_notification_was_et = 0;
 223
 224         /* Make pair[1] readable */
 225         tt_int_op(send(pair[0], &c, 1, 0), >, 0);
 226
 227         read_ev = event_new(base, pair[1], EV_READ|EV_ET|EV_PERSIST,
 228                 read_notification_cb, NULL);
 229         write_ev = event_new(base, pair[1], EV_WRITE|EV_ET|EV_PERSIST,
 230                 write_notification_cb, NULL);
 231
 232         event_add(read_ev, NULL);
 233         event_add(write_ev, NULL);
 234         event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
 235         event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
 236
 237         tt_assert(last_read_notification_was_et);
 238         tt_int_op(read_notification_count, ==, 1);
 239         tt_assert(last_write_notification_was_et);
 240         tt_int_op(write_notification_count, ==, 1);
 241
 242         event_del(read_ev);
 243
 244         /* trigger acitivity second time for the backend that can have multiple
 245          * events for one fd (like kqueue) */
 246         close(pair[0]);
 247         pair[0] = -1;
 248
 249         /* Verify that we are still edge-triggered for write notifications */
 250         event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
 251         event_base_loop(base, EVLOOP_NONBLOCK|EVLOOP_ONCE);
 252         tt_assert(last_write_notification_was_et);
 253         tt_int_op(write_notification_count, ==, 2);
 254
 255 end:
 256         if (read_ev)
 257                 event_free(read_ev);
 258         if (write_ev)
 259                 event_free(write_ev);
 260 }
 261
 262 struct testcase_t edgetriggered_testcases[] = {
 263         { "et", test_edgetriggered,
 264           TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR, &basic_setup, NULL },
 265         { "et_mix_error", test_edgetriggered_mix_error,
 266           TT_FORK|TT_NEED_SOCKETPAIR|TT_NO_LOGS, &basic_setup, NULL },
 267         { "et_multiple_events", test_edge_triggered_multiple_events,
 268           TT_FORK|TT_NEED_BASE|TT_NEED_SOCKETPAIR, &basic_setup, NULL },
 269         END_OF_TESTCASES
 270 };