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 
base_supports_et(struct event_base * base)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
read_cb(evutil_socket_t fd,short event,void * arg)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
test_edgetriggered(void * data_)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 	/* Initialize 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
test_edgetriggered_mix_error(void * data_)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
read_notification_cb(evutil_socket_t fd,short event,void * arg)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
write_notification_cb(evutil_socket_t fd,short event,void * arg)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
test_edge_triggered_multiple_events(void * data_)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 };
271