1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-mainloop.c Main loop utility
3 *
4 * Copyright © 2003, 2004 Red Hat, Inc.
5 * Copyright © 2011 Nokia Corporation
6 *
7 * Licensed under the Academic Free License version 2.1
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 *
23 */
24
25 #include <config.h>
26 #include "dbus-mainloop.h"
27
28 #ifndef DOXYGEN_SHOULD_SKIP_THIS
29
30 #include <dbus/dbus-hash.h>
31 #include <dbus/dbus-list.h>
32 #include <dbus/dbus-socket-set.h>
33 #include <dbus/dbus-watch.h>
34
35 #define MAINLOOP_SPEW 0
36
37 #if MAINLOOP_SPEW
38 #ifdef DBUS_ENABLE_VERBOSE_MODE
39 static const char*
watch_flags_to_string(int flags)40 watch_flags_to_string (int flags)
41 {
42 const char *watch_type;
43
44 if ((flags & DBUS_WATCH_READABLE) &&
45 (flags & DBUS_WATCH_WRITABLE))
46 watch_type = "readwrite";
47 else if (flags & DBUS_WATCH_READABLE)
48 watch_type = "read";
49 else if (flags & DBUS_WATCH_WRITABLE)
50 watch_type = "write";
51 else
52 watch_type = "not read or write";
53 return watch_type;
54 }
55 #endif /* DBUS_ENABLE_VERBOSE_MODE */
56 #endif /* MAINLOOP_SPEW */
57
58 struct DBusLoop
59 {
60 int refcount;
61 /** fd => dbus_malloc'd DBusList ** of references to DBusWatch */
62 DBusHashTable *watches;
63 DBusSocketSet *socket_set;
64 DBusList *timeouts;
65 int callback_list_serial;
66 int watch_count;
67 int timeout_count;
68 int depth; /**< number of recursive runs */
69 DBusList *need_dispatch;
70 /** TRUE if we will skip a watch next time because it was OOM; becomes
71 * FALSE between polling, and dealing with the results of the poll */
72 unsigned oom_watch_pending : 1;
73 };
74
75 typedef struct
76 {
77 DBusTimeout *timeout;
78 unsigned long last_tv_sec;
79 unsigned long last_tv_usec;
80 } TimeoutCallback;
81
82 #define TIMEOUT_CALLBACK(callback) ((TimeoutCallback*)callback)
83
84 static TimeoutCallback*
timeout_callback_new(DBusTimeout * timeout)85 timeout_callback_new (DBusTimeout *timeout)
86 {
87 TimeoutCallback *cb;
88
89 cb = dbus_new (TimeoutCallback, 1);
90 if (cb == NULL)
91 return NULL;
92
93 cb->timeout = timeout;
94 _dbus_get_monotonic_time (&cb->last_tv_sec,
95 &cb->last_tv_usec);
96 return cb;
97 }
98
99 static void
timeout_callback_free(TimeoutCallback * cb)100 timeout_callback_free (TimeoutCallback *cb)
101 {
102 dbus_free (cb);
103 }
104
105 static void
free_watch_table_entry(void * data)106 free_watch_table_entry (void *data)
107 {
108 DBusList **watches = data;
109 DBusWatch *watch;
110
111 /* DBusHashTable sometimes calls free_function(NULL) even if you never
112 * have NULL as a value */
113 if (watches == NULL)
114 return;
115
116 for (watch = _dbus_list_pop_first (watches);
117 watch != NULL;
118 watch = _dbus_list_pop_first (watches))
119 {
120 _dbus_watch_unref (watch);
121 }
122
123 _dbus_assert (*watches == NULL);
124 dbus_free (watches);
125 }
126
127 DBusLoop*
_dbus_loop_new(void)128 _dbus_loop_new (void)
129 {
130 DBusLoop *loop;
131
132 loop = dbus_new0 (DBusLoop, 1);
133 if (loop == NULL)
134 return NULL;
135
136 loop->watches = _dbus_hash_table_new (DBUS_HASH_INT, NULL,
137 free_watch_table_entry);
138
139 loop->socket_set = _dbus_socket_set_new (0);
140
141 if (loop->watches == NULL || loop->socket_set == NULL)
142 {
143 if (loop->watches != NULL)
144 _dbus_hash_table_unref (loop->watches);
145
146 if (loop->socket_set != NULL)
147 _dbus_socket_set_free (loop->socket_set);
148
149 dbus_free (loop);
150 return NULL;
151 }
152
153 loop->refcount = 1;
154
155 return loop;
156 }
157
158 DBusLoop *
_dbus_loop_ref(DBusLoop * loop)159 _dbus_loop_ref (DBusLoop *loop)
160 {
161 _dbus_assert (loop != NULL);
162 _dbus_assert (loop->refcount > 0);
163
164 loop->refcount += 1;
165
166 return loop;
167 }
168
169 void
_dbus_loop_unref(DBusLoop * loop)170 _dbus_loop_unref (DBusLoop *loop)
171 {
172 _dbus_assert (loop != NULL);
173 _dbus_assert (loop->refcount > 0);
174
175 loop->refcount -= 1;
176 if (loop->refcount == 0)
177 {
178 while (loop->need_dispatch)
179 {
180 DBusConnection *connection = _dbus_list_pop_first (&loop->need_dispatch);
181
182 dbus_connection_unref (connection);
183 }
184
185 _dbus_hash_table_unref (loop->watches);
186 _dbus_socket_set_free (loop->socket_set);
187 dbus_free (loop);
188 }
189 }
190
191 static DBusList **
ensure_watch_table_entry(DBusLoop * loop,int fd)192 ensure_watch_table_entry (DBusLoop *loop,
193 int fd)
194 {
195 DBusList **watches;
196
197 watches = _dbus_hash_table_lookup_int (loop->watches, fd);
198
199 if (watches == NULL)
200 {
201 watches = dbus_new0 (DBusList *, 1);
202
203 if (watches == NULL)
204 return watches;
205
206 if (!_dbus_hash_table_insert_int (loop->watches, fd, watches))
207 {
208 dbus_free (watches);
209 watches = NULL;
210 }
211 }
212
213 return watches;
214 }
215
216 static void
cull_watches_for_invalid_fd(DBusLoop * loop,int fd)217 cull_watches_for_invalid_fd (DBusLoop *loop,
218 int fd)
219 {
220 DBusList *link;
221 DBusList **watches;
222
223 _dbus_warn ("invalid request, socket fd %d not open\n", fd);
224 watches = _dbus_hash_table_lookup_int (loop->watches, fd);
225
226 if (watches != NULL)
227 {
228 for (link = _dbus_list_get_first_link (watches);
229 link != NULL;
230 link = _dbus_list_get_next_link (watches, link))
231 _dbus_watch_invalidate (link->data);
232 }
233
234 _dbus_hash_table_remove_int (loop->watches, fd);
235 }
236
237 static dbus_bool_t
gc_watch_table_entry(DBusLoop * loop,DBusList ** watches,int fd)238 gc_watch_table_entry (DBusLoop *loop,
239 DBusList **watches,
240 int fd)
241 {
242 /* If watches is already NULL we have nothing to do */
243 if (watches == NULL)
244 return FALSE;
245
246 /* We can't GC hash table entries if they're non-empty lists */
247 if (*watches != NULL)
248 return FALSE;
249
250 _dbus_hash_table_remove_int (loop->watches, fd);
251 return TRUE;
252 }
253
254 static void
refresh_watches_for_fd(DBusLoop * loop,DBusList ** watches,int fd)255 refresh_watches_for_fd (DBusLoop *loop,
256 DBusList **watches,
257 int fd)
258 {
259 DBusList *link;
260 unsigned int flags = 0;
261 dbus_bool_t interested = FALSE;
262
263 _dbus_assert (fd != -1);
264
265 if (watches == NULL)
266 watches = _dbus_hash_table_lookup_int (loop->watches, fd);
267
268 /* we allocated this in the first _dbus_loop_add_watch for the fd, and keep
269 * it until there are none left */
270 _dbus_assert (watches != NULL);
271
272 for (link = _dbus_list_get_first_link (watches);
273 link != NULL;
274 link = _dbus_list_get_next_link (watches, link))
275 {
276 if (dbus_watch_get_enabled (link->data) &&
277 !_dbus_watch_get_oom_last_time (link->data))
278 {
279 flags |= dbus_watch_get_flags (link->data);
280 interested = TRUE;
281 }
282 }
283
284 if (interested)
285 _dbus_socket_set_enable (loop->socket_set, fd, flags);
286 else
287 _dbus_socket_set_disable (loop->socket_set, fd);
288 }
289
290 dbus_bool_t
_dbus_loop_add_watch(DBusLoop * loop,DBusWatch * watch)291 _dbus_loop_add_watch (DBusLoop *loop,
292 DBusWatch *watch)
293 {
294 int fd;
295 DBusList **watches;
296
297 fd = dbus_watch_get_socket (watch);
298 _dbus_assert (fd != -1);
299
300 watches = ensure_watch_table_entry (loop, fd);
301
302 if (watches == NULL)
303 return FALSE;
304
305 if (!_dbus_list_append (watches, _dbus_watch_ref (watch)))
306 {
307 _dbus_watch_unref (watch);
308 gc_watch_table_entry (loop, watches, fd);
309
310 return FALSE;
311 }
312
313 if (_dbus_list_length_is_one (watches))
314 {
315 if (!_dbus_socket_set_add (loop->socket_set, fd,
316 dbus_watch_get_flags (watch),
317 dbus_watch_get_enabled (watch)))
318 {
319 _dbus_hash_table_remove_int (loop->watches, fd);
320 return FALSE;
321 }
322 }
323 else
324 {
325 /* we're modifying, not adding, which can't fail with OOM */
326 refresh_watches_for_fd (loop, watches, fd);
327 }
328
329 loop->callback_list_serial += 1;
330 loop->watch_count += 1;
331 return TRUE;
332 }
333
334 void
_dbus_loop_toggle_watch(DBusLoop * loop,DBusWatch * watch)335 _dbus_loop_toggle_watch (DBusLoop *loop,
336 DBusWatch *watch)
337 {
338 refresh_watches_for_fd (loop, NULL, dbus_watch_get_socket (watch));
339 }
340
341 void
_dbus_loop_remove_watch(DBusLoop * loop,DBusWatch * watch)342 _dbus_loop_remove_watch (DBusLoop *loop,
343 DBusWatch *watch)
344 {
345 DBusList **watches;
346 DBusList *link;
347 int fd;
348
349 /* This relies on people removing watches before they invalidate them,
350 * which has been safe since fd.o #33336 was fixed. Assert about it
351 * so we don't regress. */
352 fd = dbus_watch_get_socket (watch);
353 _dbus_assert (fd != -1);
354
355 watches = _dbus_hash_table_lookup_int (loop->watches, fd);
356
357 if (watches != NULL)
358 {
359 link = _dbus_list_get_first_link (watches);
360 while (link != NULL)
361 {
362 DBusList *next = _dbus_list_get_next_link (watches, link);
363 DBusWatch *this = link->data;
364
365 if (this == watch)
366 {
367 _dbus_list_remove_link (watches, link);
368 loop->callback_list_serial += 1;
369 loop->watch_count -= 1;
370 _dbus_watch_unref (this);
371
372 /* if that was the last watch for that fd, drop the hash table
373 * entry, and stop reserving space for it in the socket set */
374 if (gc_watch_table_entry (loop, watches, fd))
375 {
376 _dbus_socket_set_remove (loop->socket_set, fd);
377 }
378
379 return;
380 }
381
382 link = next;
383 }
384 }
385
386 _dbus_warn ("could not find watch %p to remove\n", watch);
387 }
388
389 dbus_bool_t
_dbus_loop_add_timeout(DBusLoop * loop,DBusTimeout * timeout)390 _dbus_loop_add_timeout (DBusLoop *loop,
391 DBusTimeout *timeout)
392 {
393 TimeoutCallback *tcb;
394
395 tcb = timeout_callback_new (timeout);
396 if (tcb == NULL)
397 return FALSE;
398
399 if (_dbus_list_append (&loop->timeouts, tcb))
400 {
401 loop->callback_list_serial += 1;
402 loop->timeout_count += 1;
403 }
404 else
405 {
406 timeout_callback_free (tcb);
407 return FALSE;
408 }
409
410 return TRUE;
411 }
412
413 void
_dbus_loop_remove_timeout(DBusLoop * loop,DBusTimeout * timeout)414 _dbus_loop_remove_timeout (DBusLoop *loop,
415 DBusTimeout *timeout)
416 {
417 DBusList *link;
418
419 link = _dbus_list_get_first_link (&loop->timeouts);
420 while (link != NULL)
421 {
422 DBusList *next = _dbus_list_get_next_link (&loop->timeouts, link);
423 TimeoutCallback *this = link->data;
424
425 if (this->timeout == timeout)
426 {
427 _dbus_list_remove_link (&loop->timeouts, link);
428 loop->callback_list_serial += 1;
429 loop->timeout_count -= 1;
430 timeout_callback_free (this);
431
432 return;
433 }
434
435 link = next;
436 }
437
438 _dbus_warn ("could not find timeout %p to remove\n", timeout);
439 }
440
441 /* Convolutions from GLib, there really must be a better way
442 * to do this.
443 */
444 static dbus_bool_t
check_timeout(unsigned long tv_sec,unsigned long tv_usec,TimeoutCallback * tcb,int * timeout)445 check_timeout (unsigned long tv_sec,
446 unsigned long tv_usec,
447 TimeoutCallback *tcb,
448 int *timeout)
449 {
450 long sec_remaining;
451 long msec_remaining;
452 unsigned long expiration_tv_sec;
453 unsigned long expiration_tv_usec;
454 long interval_seconds;
455 long interval_milliseconds;
456 int interval;
457
458 /* I'm pretty sure this function could suck (a lot) less */
459
460 interval = dbus_timeout_get_interval (tcb->timeout);
461
462 interval_seconds = interval / 1000L;
463 interval_milliseconds = interval % 1000L;
464
465 expiration_tv_sec = tcb->last_tv_sec + interval_seconds;
466 expiration_tv_usec = tcb->last_tv_usec + interval_milliseconds * 1000;
467 if (expiration_tv_usec >= 1000000)
468 {
469 expiration_tv_usec -= 1000000;
470 expiration_tv_sec += 1;
471 }
472
473 sec_remaining = expiration_tv_sec - tv_sec;
474 /* need to force this to be signed, as it is intended to sometimes
475 * produce a negative result
476 */
477 msec_remaining = ((long) expiration_tv_usec - (long) tv_usec) / 1000L;
478
479 #if MAINLOOP_SPEW
480 _dbus_verbose ("Interval is %ld seconds %ld msecs\n",
481 interval_seconds,
482 interval_milliseconds);
483 _dbus_verbose ("Now is %lu seconds %lu usecs\n",
484 tv_sec, tv_usec);
485 _dbus_verbose ("Last is %lu seconds %lu usecs\n",
486 tcb->last_tv_sec, tcb->last_tv_usec);
487 _dbus_verbose ("Exp is %lu seconds %lu usecs\n",
488 expiration_tv_sec, expiration_tv_usec);
489 _dbus_verbose ("Pre-correction, sec_remaining %ld msec_remaining %ld\n",
490 sec_remaining, msec_remaining);
491 #endif
492
493 /* We do the following in a rather convoluted fashion to deal with
494 * the fact that we don't have an integral type big enough to hold
495 * the difference of two timevals in milliseconds.
496 */
497 if (sec_remaining < 0 || (sec_remaining == 0 && msec_remaining < 0))
498 {
499 *timeout = 0;
500 }
501 else
502 {
503 if (msec_remaining < 0)
504 {
505 msec_remaining += 1000;
506 sec_remaining -= 1;
507 }
508
509 if (sec_remaining > (_DBUS_INT_MAX / 1000) ||
510 msec_remaining > _DBUS_INT_MAX)
511 *timeout = _DBUS_INT_MAX;
512 else
513 *timeout = sec_remaining * 1000 + msec_remaining;
514 }
515
516 if (*timeout > interval)
517 {
518 /* This indicates that the system clock probably moved backward */
519 _dbus_verbose ("System clock set backward! Resetting timeout.\n");
520
521 tcb->last_tv_sec = tv_sec;
522 tcb->last_tv_usec = tv_usec;
523
524 *timeout = interval;
525 }
526
527 #if MAINLOOP_SPEW
528 _dbus_verbose (" timeout expires in %d milliseconds\n", *timeout);
529 #endif
530
531 return *timeout == 0;
532 }
533
534 dbus_bool_t
_dbus_loop_dispatch(DBusLoop * loop)535 _dbus_loop_dispatch (DBusLoop *loop)
536 {
537
538 #if MAINLOOP_SPEW
539 _dbus_verbose (" %d connections to dispatch\n", _dbus_list_get_length (&loop->need_dispatch));
540 #endif
541
542 if (loop->need_dispatch == NULL)
543 return FALSE;
544
545 next:
546 while (loop->need_dispatch != NULL)
547 {
548 DBusConnection *connection = _dbus_list_pop_first (&loop->need_dispatch);
549
550 while (TRUE)
551 {
552 DBusDispatchStatus status;
553
554 status = dbus_connection_dispatch (connection);
555
556 if (status == DBUS_DISPATCH_COMPLETE)
557 {
558 dbus_connection_unref (connection);
559 goto next;
560 }
561 else
562 {
563 if (status == DBUS_DISPATCH_NEED_MEMORY)
564 _dbus_wait_for_memory ();
565 }
566 }
567 }
568
569 return TRUE;
570 }
571
572 dbus_bool_t
_dbus_loop_queue_dispatch(DBusLoop * loop,DBusConnection * connection)573 _dbus_loop_queue_dispatch (DBusLoop *loop,
574 DBusConnection *connection)
575 {
576 if (_dbus_list_append (&loop->need_dispatch, connection))
577 {
578 dbus_connection_ref (connection);
579 return TRUE;
580 }
581 else
582 return FALSE;
583 }
584
585 /* Returns TRUE if we invoked any timeouts or have ready file
586 * descriptors, which is just used in test code as a debug hack
587 */
588
589 dbus_bool_t
_dbus_loop_iterate(DBusLoop * loop,dbus_bool_t block)590 _dbus_loop_iterate (DBusLoop *loop,
591 dbus_bool_t block)
592 {
593 #define N_STACK_DESCRIPTORS 64
594 dbus_bool_t retval;
595 DBusSocketEvent ready_fds[N_STACK_DESCRIPTORS];
596 int i;
597 DBusList *link;
598 int n_ready;
599 int initial_serial;
600 long timeout;
601 int orig_depth;
602
603 retval = FALSE;
604
605 orig_depth = loop->depth;
606
607 #if MAINLOOP_SPEW
608 _dbus_verbose ("Iteration block=%d depth=%d timeout_count=%d watch_count=%d\n",
609 block, loop->depth, loop->timeout_count, loop->watch_count);
610 #endif
611
612 if (_dbus_hash_table_get_n_entries (loop->watches) == 0 &&
613 loop->timeouts == NULL)
614 goto next_iteration;
615
616 timeout = -1;
617 if (loop->timeout_count > 0)
618 {
619 unsigned long tv_sec;
620 unsigned long tv_usec;
621
622 _dbus_get_monotonic_time (&tv_sec, &tv_usec);
623
624 link = _dbus_list_get_first_link (&loop->timeouts);
625 while (link != NULL)
626 {
627 DBusList *next = _dbus_list_get_next_link (&loop->timeouts, link);
628 TimeoutCallback *tcb = link->data;
629
630 if (dbus_timeout_get_enabled (tcb->timeout))
631 {
632 int msecs_remaining;
633
634 check_timeout (tv_sec, tv_usec, tcb, &msecs_remaining);
635
636 if (timeout < 0)
637 timeout = msecs_remaining;
638 else
639 timeout = MIN (msecs_remaining, timeout);
640
641 #if MAINLOOP_SPEW
642 _dbus_verbose (" timeout added, %d remaining, aggregate timeout %ld\n",
643 msecs_remaining, timeout);
644 #endif
645
646 _dbus_assert (timeout >= 0);
647
648 if (timeout == 0)
649 break; /* it's not going to get shorter... */
650 }
651 #if MAINLOOP_SPEW
652 else
653 {
654 _dbus_verbose (" skipping disabled timeout\n");
655 }
656 #endif
657
658 link = next;
659 }
660 }
661
662 /* Never block if we have stuff to dispatch */
663 if (!block || loop->need_dispatch != NULL)
664 {
665 timeout = 0;
666 #if MAINLOOP_SPEW
667 _dbus_verbose (" timeout is 0 as we aren't blocking\n");
668 #endif
669 }
670
671 /* if a watch was OOM last time, don't wait longer than the OOM
672 * wait to re-enable it
673 */
674 if (loop->oom_watch_pending)
675 timeout = MIN (timeout, _dbus_get_oom_wait ());
676
677 #if MAINLOOP_SPEW
678 _dbus_verbose (" polling on %d descriptors timeout %ld\n", n_fds, timeout);
679 #endif
680
681 n_ready = _dbus_socket_set_poll (loop->socket_set, ready_fds,
682 _DBUS_N_ELEMENTS (ready_fds), timeout);
683
684 /* re-enable any watches we skipped this time */
685 if (loop->oom_watch_pending)
686 {
687 DBusHashIter hash_iter;
688
689 loop->oom_watch_pending = FALSE;
690
691 _dbus_hash_iter_init (loop->watches, &hash_iter);
692
693 while (_dbus_hash_iter_next (&hash_iter))
694 {
695 DBusList **watches;
696 int fd;
697 dbus_bool_t changed;
698
699 changed = FALSE;
700 fd = _dbus_hash_iter_get_int_key (&hash_iter);
701 watches = _dbus_hash_iter_get_value (&hash_iter);
702
703 for (link = _dbus_list_get_first_link (watches);
704 link != NULL;
705 link = _dbus_list_get_next_link (watches, link))
706 {
707 DBusWatch *watch = link->data;
708
709 if (_dbus_watch_get_oom_last_time (watch))
710 {
711 _dbus_watch_set_oom_last_time (watch, FALSE);
712 changed = TRUE;
713 }
714 }
715
716 if (changed)
717 refresh_watches_for_fd (loop, watches, fd);
718 }
719
720 retval = TRUE; /* return TRUE here to keep the loop going,
721 * since we don't know the watch was inactive */
722 }
723
724 initial_serial = loop->callback_list_serial;
725
726 if (loop->timeout_count > 0)
727 {
728 unsigned long tv_sec;
729 unsigned long tv_usec;
730
731 _dbus_get_monotonic_time (&tv_sec, &tv_usec);
732
733 /* It'd be nice to avoid this O(n) thingy here */
734 link = _dbus_list_get_first_link (&loop->timeouts);
735 while (link != NULL)
736 {
737 DBusList *next = _dbus_list_get_next_link (&loop->timeouts, link);
738 TimeoutCallback *tcb = link->data;
739
740 if (initial_serial != loop->callback_list_serial)
741 goto next_iteration;
742
743 if (loop->depth != orig_depth)
744 goto next_iteration;
745
746 if (dbus_timeout_get_enabled (tcb->timeout))
747 {
748 int msecs_remaining;
749
750 if (check_timeout (tv_sec, tv_usec,
751 tcb, &msecs_remaining))
752 {
753 /* Save last callback time and fire this timeout */
754 tcb->last_tv_sec = tv_sec;
755 tcb->last_tv_usec = tv_usec;
756
757 #if MAINLOOP_SPEW
758 _dbus_verbose (" invoking timeout\n");
759 #endif
760
761 /* can theoretically return FALSE on OOM, but we just
762 * let it fire again later - in practice that's what
763 * every wrapper callback in dbus-daemon used to do */
764 dbus_timeout_handle (tcb->timeout);
765
766 retval = TRUE;
767 }
768 else
769 {
770 #if MAINLOOP_SPEW
771 _dbus_verbose (" timeout has not expired\n");
772 #endif
773 }
774 }
775 #if MAINLOOP_SPEW
776 else
777 {
778 _dbus_verbose (" skipping invocation of disabled timeout\n");
779 }
780 #endif
781
782 link = next;
783 }
784 }
785
786 if (n_ready > 0)
787 {
788 for (i = 0; i < n_ready; i++)
789 {
790 DBusList **watches;
791 DBusList *next;
792 unsigned int condition;
793 dbus_bool_t any_oom;
794
795 /* FIXME I think this "restart if we change the watches"
796 * approach could result in starving watches
797 * toward the end of the list.
798 */
799 if (initial_serial != loop->callback_list_serial)
800 goto next_iteration;
801
802 if (loop->depth != orig_depth)
803 goto next_iteration;
804
805 _dbus_assert (ready_fds[i].flags != 0);
806
807 if (_DBUS_UNLIKELY (ready_fds[i].flags & _DBUS_WATCH_NVAL))
808 {
809 cull_watches_for_invalid_fd (loop, ready_fds[i].fd);
810 goto next_iteration;
811 }
812
813 condition = ready_fds[i].flags;
814 _dbus_assert ((condition & _DBUS_WATCH_NVAL) == 0);
815
816 /* condition may still be 0 if we got some
817 * weird POLLFOO thing like POLLWRBAND
818 */
819 if (condition == 0)
820 continue;
821
822 watches = _dbus_hash_table_lookup_int (loop->watches,
823 ready_fds[i].fd);
824
825 if (watches == NULL)
826 continue;
827
828 any_oom = FALSE;
829
830 for (link = _dbus_list_get_first_link (watches);
831 link != NULL;
832 link = next)
833 {
834 DBusWatch *watch = link->data;
835
836 next = _dbus_list_get_next_link (watches, link);
837
838 if (dbus_watch_get_enabled (watch))
839 {
840 dbus_bool_t oom;
841
842 oom = !dbus_watch_handle (watch, condition);
843
844 if (oom)
845 {
846 _dbus_watch_set_oom_last_time (watch, TRUE);
847 loop->oom_watch_pending = TRUE;
848 any_oom = TRUE;
849 }
850
851 #if MAINLOOP_SPEW
852 _dbus_verbose (" Invoked watch, oom = %d\n", oom);
853 #endif
854 retval = TRUE;
855
856 /* We re-check this every time, in case the callback
857 * added/removed watches, which might make our position in
858 * the linked list invalid. See the FIXME above. */
859 if (initial_serial != loop->callback_list_serial ||
860 loop->depth != orig_depth)
861 {
862 if (any_oom)
863 refresh_watches_for_fd (loop, NULL, ready_fds[i].fd);
864
865 goto next_iteration;
866 }
867 }
868 }
869
870 if (any_oom)
871 refresh_watches_for_fd (loop, watches, ready_fds[i].fd);
872 }
873 }
874
875 next_iteration:
876 #if MAINLOOP_SPEW
877 _dbus_verbose (" moving to next iteration\n");
878 #endif
879
880 if (_dbus_loop_dispatch (loop))
881 retval = TRUE;
882
883 #if MAINLOOP_SPEW
884 _dbus_verbose ("Returning %d\n", retval);
885 #endif
886
887 return retval;
888 }
889
890 void
_dbus_loop_run(DBusLoop * loop)891 _dbus_loop_run (DBusLoop *loop)
892 {
893 int our_exit_depth;
894
895 _dbus_assert (loop->depth >= 0);
896
897 _dbus_loop_ref (loop);
898
899 our_exit_depth = loop->depth;
900 loop->depth += 1;
901
902 _dbus_verbose ("Running main loop, depth %d -> %d\n",
903 loop->depth - 1, loop->depth);
904
905 while (loop->depth != our_exit_depth)
906 _dbus_loop_iterate (loop, TRUE);
907
908 _dbus_loop_unref (loop);
909 }
910
911 void
_dbus_loop_quit(DBusLoop * loop)912 _dbus_loop_quit (DBusLoop *loop)
913 {
914 _dbus_assert (loop->depth > 0);
915
916 loop->depth -= 1;
917
918 _dbus_verbose ("Quit main loop, depth %d -> %d\n",
919 loop->depth + 1, loop->depth);
920 }
921
922 int
_dbus_get_oom_wait(void)923 _dbus_get_oom_wait (void)
924 {
925 #ifdef DBUS_BUILD_TESTS
926 /* make tests go fast */
927 return 0;
928 #else
929 return 500;
930 #endif
931 }
932
933 void
_dbus_wait_for_memory(void)934 _dbus_wait_for_memory (void)
935 {
936 _dbus_verbose ("Waiting for more memory\n");
937 _dbus_sleep_milliseconds (_dbus_get_oom_wait ());
938 }
939
940 #endif /* !DOXYGEN_SHOULD_SKIP_THIS */
941