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