summaryrefslogtreecommitdiff
path: root/source3/lib/events.c
blob: 77589f8e7e2060d83d1ffca952e7c1c599ac9c65 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
/*
   Unix SMB/CIFS implementation.
   Timed event library.
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Volker Lendecke 2005-2007

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "lib/tevent/tevent_internal.h"
#include "../lib/util/select.h"
#include "system/select.h"

struct tevent_poll_private {
	/*
	 * Index from file descriptor into the pollfd array
	 */
	int *pollfd_idx;

	/*
	 * Cache for s3_event_loop_once to avoid reallocs
	 */
	struct pollfd *pfds;
};

static struct tevent_poll_private *tevent_get_poll_private(
	struct tevent_context *ev)
{
	struct tevent_poll_private *state;

	state = (struct tevent_poll_private *)ev->additional_data;
	if (state == NULL) {
		state = talloc_zero(ev, struct tevent_poll_private);
		ev->additional_data = (void *)state;
		if (state == NULL) {
			DEBUG(10, ("talloc failed\n"));
		}
	}
	return state;
}

static void count_fds(struct tevent_context *ev,
		      int *pnum_fds, int *pmax_fd)
{
	struct tevent_fd *fde;
	int num_fds = 0;
	int max_fd = 0;

	for (fde = ev->fd_events; fde != NULL; fde = fde->next) {
		if (fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE)) {
			num_fds += 1;
			if (fde->fd > max_fd) {
				max_fd = fde->fd;
			}
		}
	}
	*pnum_fds = num_fds;
	*pmax_fd = max_fd;
}

bool event_add_to_poll_args(struct tevent_context *ev, TALLOC_CTX *mem_ctx,
			    struct pollfd **pfds, int *pnum_pfds,
			    int *ptimeout)
{
	struct tevent_poll_private *state;
	struct tevent_fd *fde;
	int i, num_fds, max_fd, num_pollfds, idx_len;
	struct pollfd *fds;
	struct timeval now, diff;
	int timeout;

	state = tevent_get_poll_private(ev);
	if (state == NULL) {
		return false;
	}
	count_fds(ev, &num_fds, &max_fd);

	idx_len = max_fd+1;

	if (talloc_array_length(state->pollfd_idx) < idx_len) {
		state->pollfd_idx = talloc_realloc(
			state, state->pollfd_idx, int, idx_len);
		if (state->pollfd_idx == NULL) {
			DEBUG(10, ("talloc_realloc failed\n"));
			return false;
		}
	}

	fds = *pfds;
	num_pollfds = *pnum_pfds;

	/*
	 * The +1 is for the sys_poll calling convention. It expects
	 * an array 1 longer for the signal pipe
	 */

	if (talloc_array_length(fds) < num_pollfds + num_fds + 1) {
		fds = talloc_realloc(mem_ctx, fds, struct pollfd,
					   num_pollfds + num_fds + 1);
		if (fds == NULL) {
			DEBUG(10, ("talloc_realloc failed\n"));
			return false;
		}
	}

	memset(&fds[num_pollfds], 0, sizeof(struct pollfd) * num_fds);

	/*
	 * This needs tuning. We need to cope with multiple fde's for a file
	 * descriptor. The problem is that we need to re-use pollfd_idx across
	 * calls for efficiency. One way would be a direct bitmask that might
	 * be initialized quicker, but our bitmap_init implementation is
	 * pretty heavy-weight as well.
	 */
	for (i=0; i<idx_len; i++) {
		state->pollfd_idx[i] = -1;
	}

	for (fde = ev->fd_events; fde; fde = fde->next) {
		struct pollfd *pfd;

		if ((fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE)) == 0) {
			continue;
		}

		if (state->pollfd_idx[fde->fd] == -1) {
			/*
			 * We haven't seen this fd yet. Allocate a new pollfd.
			 */
			state->pollfd_idx[fde->fd] = num_pollfds;
			pfd = &fds[num_pollfds];
			num_pollfds += 1;
		} else {
			/*
			 * We have already seen this fd. OR in the flags.
			 */
			pfd = &fds[state->pollfd_idx[fde->fd]];
		}

		pfd->fd = fde->fd;

		if (fde->flags & EVENT_FD_READ) {
			pfd->events |= (POLLIN|POLLHUP);
		}
		if (fde->flags & EVENT_FD_WRITE) {
			pfd->events |= POLLOUT;
		}
	}
	*pfds = fds;
	*pnum_pfds = num_pollfds;

	if (ev->immediate_events != NULL) {
		*ptimeout = 0;
		return true;
	}
	if (ev->timer_events == NULL) {
		*ptimeout = MIN(*ptimeout, INT_MAX);
		return true;
	}

	now = timeval_current();
	diff = timeval_until(&now, &ev->timer_events->next_event);
	timeout = timeval_to_msec(diff);

	if (timeout < *ptimeout) {
		*ptimeout = timeout;
	}

	return true;
}

bool run_events_poll(struct tevent_context *ev, int pollrtn,
		     struct pollfd *pfds, int num_pfds)
{
	struct tevent_poll_private *state;
	int *pollfd_idx;
	struct tevent_fd *fde;
	struct timeval now;

	if (ev->signal_events &&
	    tevent_common_check_signal(ev)) {
		return true;
	}

	if (ev->immediate_events &&
	    tevent_common_loop_immediate(ev)) {
		return true;
	}

	GetTimeOfDay(&now);

	if ((ev->timer_events != NULL)
	    && (timeval_compare(&now, &ev->timer_events->next_event) >= 0)) {
		/* this older events system did not auto-free timed
		   events on running them, and had a race condition
		   where the event could be called twice if the
		   talloc_free of the te happened after the callback
		   made a call which invoked the event loop. To avoid
		   this while still allowing old code which frees the
		   te, we need to create a temporary context which
		   will be used to ensure the te is freed. We also
		   remove the te from the timed event list before we
		   call the handler, to ensure we can't loop */

		struct tevent_timer *te = ev->timer_events;
		TALLOC_CTX *tmp_ctx = talloc_new(ev);

		DEBUG(10, ("Running timed event \"%s\" %p\n",
			   ev->timer_events->handler_name, ev->timer_events));

		DLIST_REMOVE(ev->timer_events, te);
		talloc_steal(tmp_ctx, te);

		te->handler(ev, te, now, te->private_data);

		talloc_free(tmp_ctx);
		return true;
	}

	if (pollrtn <= 0) {
		/*
		 * No fd ready
		 */
		return false;
	}

	state = (struct tevent_poll_private *)ev->additional_data;
	pollfd_idx = state->pollfd_idx;

	for (fde = ev->fd_events; fde; fde = fde->next) {
		struct pollfd *pfd;
		uint16 flags = 0;

		if ((fde->flags & (EVENT_FD_READ|EVENT_FD_WRITE)) == 0) {
			continue;
		}

		if (pollfd_idx[fde->fd] >= num_pfds) {
			DEBUG(1, ("internal error: pollfd_idx[fde->fd] (%d) "
				  ">= num_pfds (%d)\n", pollfd_idx[fde->fd],
				  num_pfds));
			return false;
		}
		pfd = &pfds[pollfd_idx[fde->fd]];

		if (pfd->fd != fde->fd) {
			DEBUG(1, ("internal error: pfd->fd (%d) "
				  "!= fde->fd (%d)\n", pollfd_idx[fde->fd],
                                  num_pfds));
			return false;
		}

		if (pfd->revents & (POLLHUP|POLLERR)) {
			/* If we only wait for EVENT_FD_WRITE, we
			   should not tell the event handler about it,
			   and remove the writable flag, as we only
			   report errors when waiting for read events
			   to match the select behavior. */
			if (!(fde->flags & EVENT_FD_READ)) {
				EVENT_FD_NOT_WRITEABLE(fde);
				continue;
			}
			flags |= EVENT_FD_READ;
		}

		if (pfd->revents & POLLIN) {
			flags |= EVENT_FD_READ;
		}
		if (pfd->revents & POLLOUT) {
			flags |= EVENT_FD_WRITE;
		}
		if (flags & fde->flags) {
			DLIST_DEMOTE(ev->fd_events, fde, struct tevent_fd);
			fde->handler(ev, fde, flags, fde->private_data);
			return true;
		}
	}

	return false;
}

struct timeval *get_timed_events_timeout(struct tevent_context *ev,
					 struct timeval *to_ret)
{
	struct timeval now;

	if ((ev->timer_events == NULL) && (ev->immediate_events == NULL)) {
		return NULL;
	}
	if (ev->immediate_events != NULL) {
		*to_ret = timeval_zero();
		return to_ret;
	}

	now = timeval_current();
	*to_ret = timeval_until(&now, &ev->timer_events->next_event);

	DEBUG(10, ("timed_events_timeout: %d/%d\n", (int)to_ret->tv_sec,
		(int)to_ret->tv_usec));

	return to_ret;
}

static int s3_event_loop_once(struct tevent_context *ev, const char *location)
{
	struct tevent_poll_private *state;
	int timeout;
	int num_pfds;
	int ret;

	timeout = INT_MAX;

	state = tevent_get_poll_private(ev);
	if (state == NULL) {
		errno = ENOMEM;
		return -1;
	}

	if (run_events_poll(ev, 0, NULL, 0)) {
		return 0;
	}

	num_pfds = 0;
	if (!event_add_to_poll_args(ev, state,
				    &state->pfds, &num_pfds, &timeout)) {
		return -1;
	}

	ret = sys_poll(state->pfds, num_pfds, timeout);
	if (ret == -1 && errno != EINTR) {
		tevent_debug(ev, TEVENT_DEBUG_FATAL,
			     "poll() failed: %d:%s\n",
			     errno, strerror(errno));
		return -1;
	}

	run_events_poll(ev, ret, state->pfds, num_pfds);
	return 0;
}

static int s3_event_context_init(struct tevent_context *ev)
{
	return 0;
}

void dump_event_list(struct tevent_context *ev)
{
	struct tevent_timer *te;
	struct tevent_fd *fe;
	struct timeval evt, now;

	if (!ev) {
		return;
	}

	now = timeval_current();

	DEBUG(10,("dump_event_list:\n"));

	for (te = ev->timer_events; te; te = te->next) {

		evt = timeval_until(&now, &te->next_event);

		DEBUGADD(10,("Timed Event \"%s\" %p handled in %d seconds (at %s)\n",
			   te->handler_name,
			   te,
			   (int)evt.tv_sec,
			   http_timestring(talloc_tos(), te->next_event.tv_sec)));
	}

	for (fe = ev->fd_events; fe; fe = fe->next) {

		DEBUGADD(10,("FD Event %d %p, flags: 0x%04x\n",
			   fe->fd,
			   fe,
			   fe->flags));
	}
}

static const struct tevent_ops s3_event_ops = {
	.context_init		= s3_event_context_init,
	.add_fd			= tevent_common_add_fd,
	.set_fd_close_fn	= tevent_common_fd_set_close_fn,
	.get_fd_flags		= tevent_common_fd_get_flags,
	.set_fd_flags		= tevent_common_fd_set_flags,
	.add_timer		= tevent_common_add_timer,
	.schedule_immediate	= tevent_common_schedule_immediate,
	.add_signal		= tevent_common_add_signal,
	.loop_once		= s3_event_loop_once,
	.loop_wait		= tevent_common_loop_wait,
};

static bool s3_tevent_init(void)
{
	static bool initialized;
	if (initialized) {
		return true;
	}
	initialized = tevent_register_backend("s3", &s3_event_ops);
	tevent_set_default_backend("s3");
	return initialized;
}

/*
  this is used to catch debug messages from events
*/
static void s3_event_debug(void *context, enum tevent_debug_level level,
			   const char *fmt, va_list ap)  PRINTF_ATTRIBUTE(3,0);

static void s3_event_debug(void *context, enum tevent_debug_level level,
			   const char *fmt, va_list ap)
{
	int samba_level = -1;
	char *s = NULL;
	switch (level) {
	case TEVENT_DEBUG_FATAL:
		samba_level = 0;
		break;
	case TEVENT_DEBUG_ERROR:
		samba_level = 1;
		break;
	case TEVENT_DEBUG_WARNING:
		samba_level = 2;
		break;
	case TEVENT_DEBUG_TRACE:
		samba_level = 11;
		break;

	};
	if (vasprintf(&s, fmt, ap) == -1) {
		return;
	}
	DEBUG(samba_level, ("s3_event: %s", s));
	free(s);
}

struct tevent_context *s3_tevent_context_init(TALLOC_CTX *mem_ctx)
{
	struct tevent_context *ev;

	s3_tevent_init();

	ev = tevent_context_init_byname(mem_ctx, "s3");
	if (ev) {
		tevent_set_debug(ev, s3_event_debug, NULL);
	}

	return ev;
}

struct idle_event {
	struct timed_event *te;
	struct timeval interval;
	char *name;
	bool (*handler)(const struct timeval *now, void *private_data);
	void *private_data;
};

static void smbd_idle_event_handler(struct event_context *ctx,
				    struct timed_event *te,
				    struct timeval now,
				    void *private_data)
{
	struct idle_event *event =
		talloc_get_type_abort(private_data, struct idle_event);

	TALLOC_FREE(event->te);

	DEBUG(10,("smbd_idle_event_handler: %s %p called\n",
		  event->name, event->te));

	if (!event->handler(&now, event->private_data)) {
		DEBUG(10,("smbd_idle_event_handler: %s %p stopped\n",
			  event->name, event->te));
		/* Don't repeat, delete ourselves */
		TALLOC_FREE(event);
		return;
	}

	DEBUG(10,("smbd_idle_event_handler: %s %p rescheduled\n",
		  event->name, event->te));

	event->te = event_add_timed(ctx, event,
				    timeval_sum(&now, &event->interval),
				    smbd_idle_event_handler, event);

	/* We can't do much but fail here. */
	SMB_ASSERT(event->te != NULL);
}

struct idle_event *event_add_idle(struct event_context *event_ctx,
				  TALLOC_CTX *mem_ctx,
				  struct timeval interval,
				  const char *name,
				  bool (*handler)(const struct timeval *now,
						  void *private_data),
				  void *private_data)
{
	struct idle_event *result;
	struct timeval now = timeval_current();

	result = talloc(mem_ctx, struct idle_event);
	if (result == NULL) {
		DEBUG(0, ("talloc failed\n"));
		return NULL;
	}

	result->interval = interval;
	result->handler = handler;
	result->private_data = private_data;

	if (!(result->name = talloc_asprintf(result, "idle_evt(%s)", name))) {
		DEBUG(0, ("talloc failed\n"));
		TALLOC_FREE(result);
		return NULL;
	}

	result->te = event_add_timed(event_ctx, result,
				     timeval_sum(&now, &interval),
				     smbd_idle_event_handler, result);
	if (result->te == NULL) {
		DEBUG(0, ("event_add_timed failed\n"));
		TALLOC_FREE(result);
		return NULL;
	}

	DEBUG(10,("event_add_idle: %s %p\n", result->name, result->te));
	return result;
}