stubs: Move qemu_fd_register stub to util/main-loop.c
[qemu.git] / util / main-loop.c
1 /*
2 * QEMU System Emulator
3 *
4 * Copyright (c) 2003-2008 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu/cutils.h"
28 #include "qemu/timer.h"
29 #include "sysemu/qtest.h"
30 #include "sysemu/cpus.h"
31 #include "sysemu/replay.h"
32 #include "qemu/main-loop.h"
33 #include "block/aio.h"
34 #include "qemu/error-report.h"
35 #include "qemu/queue.h"
36
37 #ifndef _WIN32
38 #include <sys/wait.h>
39 #endif
40
41 #ifndef _WIN32
42
43 /* If we have signalfd, we mask out the signals we want to handle and then
44 * use signalfd to listen for them. We rely on whatever the current signal
45 * handler is to dispatch the signals when we receive them.
46 */
47 static void sigfd_handler(void *opaque)
48 {
49 int fd = (intptr_t)opaque;
50 struct qemu_signalfd_siginfo info;
51 struct sigaction action;
52 ssize_t len;
53
54 while (1) {
55 do {
56 len = read(fd, &info, sizeof(info));
57 } while (len == -1 && errno == EINTR);
58
59 if (len == -1 && errno == EAGAIN) {
60 break;
61 }
62
63 if (len != sizeof(info)) {
64 error_report("read from sigfd returned %zd: %s", len,
65 g_strerror(errno));
66 return;
67 }
68
69 sigaction(info.ssi_signo, NULL, &action);
70 if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
71 sigaction_invoke(&action, &info);
72 } else if (action.sa_handler) {
73 action.sa_handler(info.ssi_signo);
74 }
75 }
76 }
77
78 static int qemu_signal_init(Error **errp)
79 {
80 int sigfd;
81 sigset_t set;
82
83 /*
84 * SIG_IPI must be blocked in the main thread and must not be caught
85 * by sigwait() in the signal thread. Otherwise, the cpu thread will
86 * not catch it reliably.
87 */
88 sigemptyset(&set);
89 sigaddset(&set, SIG_IPI);
90 sigaddset(&set, SIGIO);
91 sigaddset(&set, SIGALRM);
92 sigaddset(&set, SIGBUS);
93 /* SIGINT cannot be handled via signalfd, so that ^C can be used
94 * to interrupt QEMU when it is being run under gdb. SIGHUP and
95 * SIGTERM are also handled asynchronously, even though it is not
96 * strictly necessary, because they use the same handler as SIGINT.
97 */
98 pthread_sigmask(SIG_BLOCK, &set, NULL);
99
100 sigdelset(&set, SIG_IPI);
101 sigfd = qemu_signalfd(&set);
102 if (sigfd == -1) {
103 error_setg_errno(errp, errno, "failed to create signalfd");
104 return -errno;
105 }
106
107 fcntl_setfl(sigfd, O_NONBLOCK);
108
109 qemu_set_fd_handler(sigfd, sigfd_handler, NULL, (void *)(intptr_t)sigfd);
110
111 return 0;
112 }
113
114 #else /* _WIN32 */
115
116 static int qemu_signal_init(Error **errp)
117 {
118 return 0;
119 }
120 #endif
121
122 static AioContext *qemu_aio_context;
123 static QEMUBH *qemu_notify_bh;
124
125 static void notify_event_cb(void *opaque)
126 {
127 /* No need to do anything; this bottom half is only used to
128 * kick the kernel out of ppoll/poll/WaitForMultipleObjects.
129 */
130 }
131
132 AioContext *qemu_get_aio_context(void)
133 {
134 return qemu_aio_context;
135 }
136
137 void qemu_notify_event(void)
138 {
139 if (!qemu_aio_context) {
140 return;
141 }
142 qemu_bh_schedule(qemu_notify_bh);
143 }
144
145 static GArray *gpollfds;
146
147 int qemu_init_main_loop(Error **errp)
148 {
149 int ret;
150 GSource *src;
151
152 init_clocks(qemu_timer_notify_cb);
153
154 ret = qemu_signal_init(errp);
155 if (ret) {
156 return ret;
157 }
158
159 qemu_aio_context = aio_context_new(errp);
160 if (!qemu_aio_context) {
161 return -EMFILE;
162 }
163 qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL);
164 gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
165 src = aio_get_g_source(qemu_aio_context);
166 g_source_set_name(src, "aio-context");
167 g_source_attach(src, NULL);
168 g_source_unref(src);
169 src = iohandler_get_g_source();
170 g_source_set_name(src, "io-handler");
171 g_source_attach(src, NULL);
172 g_source_unref(src);
173 return 0;
174 }
175
176 static int max_priority;
177
178 #ifndef _WIN32
179 static int glib_pollfds_idx;
180 static int glib_n_poll_fds;
181
182 void qemu_fd_register(int fd)
183 {
184 }
185
186 static void glib_pollfds_fill(int64_t *cur_timeout)
187 {
188 GMainContext *context = g_main_context_default();
189 int timeout = 0;
190 int64_t timeout_ns;
191 int n;
192
193 g_main_context_prepare(context, &max_priority);
194
195 glib_pollfds_idx = gpollfds->len;
196 n = glib_n_poll_fds;
197 do {
198 GPollFD *pfds;
199 glib_n_poll_fds = n;
200 g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
201 pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
202 n = g_main_context_query(context, max_priority, &timeout, pfds,
203 glib_n_poll_fds);
204 } while (n != glib_n_poll_fds);
205
206 if (timeout < 0) {
207 timeout_ns = -1;
208 } else {
209 timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
210 }
211
212 *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
213 }
214
215 static void glib_pollfds_poll(void)
216 {
217 GMainContext *context = g_main_context_default();
218 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
219
220 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
221 g_main_context_dispatch(context);
222 }
223 }
224
225 #define MAX_MAIN_LOOP_SPIN (1000)
226
227 static int os_host_main_loop_wait(int64_t timeout)
228 {
229 GMainContext *context = g_main_context_default();
230 int ret;
231
232 g_main_context_acquire(context);
233
234 glib_pollfds_fill(&timeout);
235
236 qemu_mutex_unlock_iothread();
237 replay_mutex_unlock();
238
239 ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
240
241 replay_mutex_lock();
242 qemu_mutex_lock_iothread();
243
244 glib_pollfds_poll();
245
246 g_main_context_release(context);
247
248 return ret;
249 }
250 #else
251 /***********************************************************/
252 /* Polling handling */
253
254 typedef struct PollingEntry {
255 PollingFunc *func;
256 void *opaque;
257 struct PollingEntry *next;
258 } PollingEntry;
259
260 static PollingEntry *first_polling_entry;
261
262 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
263 {
264 PollingEntry **ppe, *pe;
265 pe = g_malloc0(sizeof(PollingEntry));
266 pe->func = func;
267 pe->opaque = opaque;
268 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
269 *ppe = pe;
270 return 0;
271 }
272
273 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
274 {
275 PollingEntry **ppe, *pe;
276 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
277 pe = *ppe;
278 if (pe->func == func && pe->opaque == opaque) {
279 *ppe = pe->next;
280 g_free(pe);
281 break;
282 }
283 }
284 }
285
286 /***********************************************************/
287 /* Wait objects support */
288 typedef struct WaitObjects {
289 int num;
290 int revents[MAXIMUM_WAIT_OBJECTS + 1];
291 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
292 WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
293 void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
294 } WaitObjects;
295
296 static WaitObjects wait_objects = {0};
297
298 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
299 {
300 WaitObjects *w = &wait_objects;
301 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
302 return -1;
303 }
304 w->events[w->num] = handle;
305 w->func[w->num] = func;
306 w->opaque[w->num] = opaque;
307 w->revents[w->num] = 0;
308 w->num++;
309 return 0;
310 }
311
312 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
313 {
314 int i, found;
315 WaitObjects *w = &wait_objects;
316
317 found = 0;
318 for (i = 0; i < w->num; i++) {
319 if (w->events[i] == handle) {
320 found = 1;
321 }
322 if (found) {
323 w->events[i] = w->events[i + 1];
324 w->func[i] = w->func[i + 1];
325 w->opaque[i] = w->opaque[i + 1];
326 w->revents[i] = w->revents[i + 1];
327 }
328 }
329 if (found) {
330 w->num--;
331 }
332 }
333
334 void qemu_fd_register(int fd)
335 {
336 WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
337 FD_READ | FD_ACCEPT | FD_CLOSE |
338 FD_CONNECT | FD_WRITE | FD_OOB);
339 }
340
341 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
342 fd_set *xfds)
343 {
344 int nfds = -1;
345 int i;
346
347 for (i = 0; i < pollfds->len; i++) {
348 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
349 int fd = pfd->fd;
350 int events = pfd->events;
351 if (events & G_IO_IN) {
352 FD_SET(fd, rfds);
353 nfds = MAX(nfds, fd);
354 }
355 if (events & G_IO_OUT) {
356 FD_SET(fd, wfds);
357 nfds = MAX(nfds, fd);
358 }
359 if (events & G_IO_PRI) {
360 FD_SET(fd, xfds);
361 nfds = MAX(nfds, fd);
362 }
363 }
364 return nfds;
365 }
366
367 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
368 fd_set *wfds, fd_set *xfds)
369 {
370 int i;
371
372 for (i = 0; i < pollfds->len; i++) {
373 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
374 int fd = pfd->fd;
375 int revents = 0;
376
377 if (FD_ISSET(fd, rfds)) {
378 revents |= G_IO_IN;
379 }
380 if (FD_ISSET(fd, wfds)) {
381 revents |= G_IO_OUT;
382 }
383 if (FD_ISSET(fd, xfds)) {
384 revents |= G_IO_PRI;
385 }
386 pfd->revents = revents & pfd->events;
387 }
388 }
389
390 static int os_host_main_loop_wait(int64_t timeout)
391 {
392 GMainContext *context = g_main_context_default();
393 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
394 int select_ret = 0;
395 int g_poll_ret, ret, i, n_poll_fds;
396 PollingEntry *pe;
397 WaitObjects *w = &wait_objects;
398 gint poll_timeout;
399 int64_t poll_timeout_ns;
400 static struct timeval tv0;
401 fd_set rfds, wfds, xfds;
402 int nfds;
403
404 g_main_context_acquire(context);
405
406 /* XXX: need to suppress polling by better using win32 events */
407 ret = 0;
408 for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
409 ret |= pe->func(pe->opaque);
410 }
411 if (ret != 0) {
412 g_main_context_release(context);
413 return ret;
414 }
415
416 FD_ZERO(&rfds);
417 FD_ZERO(&wfds);
418 FD_ZERO(&xfds);
419 nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
420 if (nfds >= 0) {
421 select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
422 if (select_ret != 0) {
423 timeout = 0;
424 }
425 if (select_ret > 0) {
426 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
427 }
428 }
429
430 g_main_context_prepare(context, &max_priority);
431 n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
432 poll_fds, ARRAY_SIZE(poll_fds));
433 g_assert(n_poll_fds + w->num <= ARRAY_SIZE(poll_fds));
434
435 for (i = 0; i < w->num; i++) {
436 poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
437 poll_fds[n_poll_fds + i].events = G_IO_IN;
438 }
439
440 if (poll_timeout < 0) {
441 poll_timeout_ns = -1;
442 } else {
443 poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
444 }
445
446 poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
447
448 qemu_mutex_unlock_iothread();
449
450 replay_mutex_unlock();
451
452 g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
453
454 replay_mutex_lock();
455
456 qemu_mutex_lock_iothread();
457 if (g_poll_ret > 0) {
458 for (i = 0; i < w->num; i++) {
459 w->revents[i] = poll_fds[n_poll_fds + i].revents;
460 }
461 for (i = 0; i < w->num; i++) {
462 if (w->revents[i] && w->func[i]) {
463 w->func[i](w->opaque[i]);
464 }
465 }
466 }
467
468 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
469 g_main_context_dispatch(context);
470 }
471
472 g_main_context_release(context);
473
474 return select_ret || g_poll_ret;
475 }
476 #endif
477
478 static NotifierList main_loop_poll_notifiers =
479 NOTIFIER_LIST_INITIALIZER(main_loop_poll_notifiers);
480
481 void main_loop_poll_add_notifier(Notifier *notify)
482 {
483 notifier_list_add(&main_loop_poll_notifiers, notify);
484 }
485
486 void main_loop_poll_remove_notifier(Notifier *notify)
487 {
488 notifier_remove(notify);
489 }
490
491 void main_loop_wait(int nonblocking)
492 {
493 MainLoopPoll mlpoll = {
494 .state = MAIN_LOOP_POLL_FILL,
495 .timeout = UINT32_MAX,
496 .pollfds = gpollfds,
497 };
498 int ret;
499 int64_t timeout_ns;
500
501 if (nonblocking) {
502 mlpoll.timeout = 0;
503 }
504
505 /* poll any events */
506 g_array_set_size(gpollfds, 0); /* reset for new iteration */
507 /* XXX: separate device handlers from system ones */
508 notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
509
510 if (mlpoll.timeout == UINT32_MAX) {
511 timeout_ns = -1;
512 } else {
513 timeout_ns = (uint64_t)mlpoll.timeout * (int64_t)(SCALE_MS);
514 }
515
516 timeout_ns = qemu_soonest_timeout(timeout_ns,
517 timerlistgroup_deadline_ns(
518 &main_loop_tlg));
519
520 ret = os_host_main_loop_wait(timeout_ns);
521 mlpoll.state = ret < 0 ? MAIN_LOOP_POLL_ERR : MAIN_LOOP_POLL_OK;
522 notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
523
524 /* CPU thread can infinitely wait for event after
525 missing the warp */
526 qemu_start_warp_timer();
527 qemu_clock_run_all_timers();
528 }
529
530 /* Functions to operate on the main QEMU AioContext. */
531
532 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
533 {
534 return aio_bh_new(qemu_aio_context, cb, opaque);
535 }
536
537 /*
538 * Functions to operate on the I/O handler AioContext.
539 * This context runs on top of main loop. We can't reuse qemu_aio_context
540 * because iohandlers mustn't be polled by aio_poll(qemu_aio_context).
541 */
542 static AioContext *iohandler_ctx;
543
544 static void iohandler_init(void)
545 {
546 if (!iohandler_ctx) {
547 iohandler_ctx = aio_context_new(&error_abort);
548 }
549 }
550
551 AioContext *iohandler_get_aio_context(void)
552 {
553 iohandler_init();
554 return iohandler_ctx;
555 }
556
557 GSource *iohandler_get_g_source(void)
558 {
559 iohandler_init();
560 return aio_get_g_source(iohandler_ctx);
561 }
562
563 void qemu_set_fd_handler(int fd,
564 IOHandler *fd_read,
565 IOHandler *fd_write,
566 void *opaque)
567 {
568 iohandler_init();
569 aio_set_fd_handler(iohandler_ctx, fd, false,
570 fd_read, fd_write, NULL, opaque);
571 }
572
573 void event_notifier_set_handler(EventNotifier *e,
574 EventNotifierHandler *handler)
575 {
576 iohandler_init();
577 aio_set_event_notifier(iohandler_ctx, e, false,
578 handler, NULL);
579 }
580
581 /* reaping of zombies. right now we're not passing the status to
582 anyone, but it would be possible to add a callback. */
583 #ifndef _WIN32
584 typedef struct ChildProcessRecord {
585 int pid;
586 QLIST_ENTRY(ChildProcessRecord) next;
587 } ChildProcessRecord;
588
589 static QLIST_HEAD(, ChildProcessRecord) child_watches =
590 QLIST_HEAD_INITIALIZER(child_watches);
591
592 static QEMUBH *sigchld_bh;
593
594 static void sigchld_handler(int signal)
595 {
596 qemu_bh_schedule(sigchld_bh);
597 }
598
599 static void sigchld_bh_handler(void *opaque)
600 {
601 ChildProcessRecord *rec, *next;
602
603 QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
604 if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
605 QLIST_REMOVE(rec, next);
606 g_free(rec);
607 }
608 }
609 }
610
611 static void qemu_init_child_watch(void)
612 {
613 struct sigaction act;
614 sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
615
616 memset(&act, 0, sizeof(act));
617 act.sa_handler = sigchld_handler;
618 act.sa_flags = SA_NOCLDSTOP;
619 sigaction(SIGCHLD, &act, NULL);
620 }
621
622 int qemu_add_child_watch(pid_t pid)
623 {
624 ChildProcessRecord *rec;
625
626 if (!sigchld_bh) {
627 qemu_init_child_watch();
628 }
629
630 QLIST_FOREACH(rec, &child_watches, next) {
631 if (rec->pid == pid) {
632 return 1;
633 }
634 }
635 rec = g_malloc0(sizeof(ChildProcessRecord));
636 rec->pid = pid;
637 QLIST_INSERT_HEAD(&child_watches, rec, next);
638 return 0;
639 }
640 #endif