Merge remote-tracking branch 'remotes/kraxel/tags/ui-20210219-pull-request' into...
[qemu/ar7.git] / util / main-loop.c
blob6bfc7c46f58e650f8f05fde24bbc154b0f4d3250
1 /*
2 * QEMU System Emulator
4 * Copyright (c) 2003-2008 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
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/cpu-timers.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 #include "qemu/compiler.h"
38 #ifndef _WIN32
39 #include <sys/wait.h>
40 #endif
42 #ifndef _WIN32
44 /* If we have signalfd, we mask out the signals we want to handle and then
45 * use signalfd to listen for them. We rely on whatever the current signal
46 * handler is to dispatch the signals when we receive them.
49 * Disable CFI checks.
50 * We are going to call a signal hander directly. Such handler may or may not
51 * have been defined in our binary, so there's no guarantee that the pointer
52 * used to set the handler is a cfi-valid pointer. Since the handlers are
53 * stored in kernel memory, changing the handler to an attacker-defined
54 * function requires being able to call a sigaction() syscall,
55 * which is not as easy as overwriting a pointer in memory.
57 QEMU_DISABLE_CFI
58 static void sigfd_handler(void *opaque)
60 int fd = (intptr_t)opaque;
61 struct qemu_signalfd_siginfo info;
62 struct sigaction action;
63 ssize_t len;
65 while (1) {
66 do {
67 len = read(fd, &info, sizeof(info));
68 } while (len == -1 && errno == EINTR);
70 if (len == -1 && errno == EAGAIN) {
71 break;
74 if (len != sizeof(info)) {
75 error_report("read from sigfd returned %zd: %s", len,
76 g_strerror(errno));
77 return;
80 sigaction(info.ssi_signo, NULL, &action);
81 if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
82 sigaction_invoke(&action, &info);
83 } else if (action.sa_handler) {
84 action.sa_handler(info.ssi_signo);
89 static int qemu_signal_init(Error **errp)
91 int sigfd;
92 sigset_t set;
95 * SIG_IPI must be blocked in the main thread and must not be caught
96 * by sigwait() in the signal thread. Otherwise, the cpu thread will
97 * not catch it reliably.
99 sigemptyset(&set);
100 sigaddset(&set, SIG_IPI);
101 sigaddset(&set, SIGIO);
102 sigaddset(&set, SIGALRM);
103 sigaddset(&set, SIGBUS);
104 /* SIGINT cannot be handled via signalfd, so that ^C can be used
105 * to interrupt QEMU when it is being run under gdb. SIGHUP and
106 * SIGTERM are also handled asynchronously, even though it is not
107 * strictly necessary, because they use the same handler as SIGINT.
109 pthread_sigmask(SIG_BLOCK, &set, NULL);
111 sigdelset(&set, SIG_IPI);
112 sigfd = qemu_signalfd(&set);
113 if (sigfd == -1) {
114 error_setg_errno(errp, errno, "failed to create signalfd");
115 return -errno;
118 fcntl_setfl(sigfd, O_NONBLOCK);
120 qemu_set_fd_handler(sigfd, sigfd_handler, NULL, (void *)(intptr_t)sigfd);
122 return 0;
125 #else /* _WIN32 */
127 static int qemu_signal_init(Error **errp)
129 return 0;
131 #endif
133 static AioContext *qemu_aio_context;
134 static QEMUBH *qemu_notify_bh;
136 static void notify_event_cb(void *opaque)
138 /* No need to do anything; this bottom half is only used to
139 * kick the kernel out of ppoll/poll/WaitForMultipleObjects.
143 AioContext *qemu_get_aio_context(void)
145 return qemu_aio_context;
148 void qemu_notify_event(void)
150 if (!qemu_aio_context) {
151 return;
153 qemu_bh_schedule(qemu_notify_bh);
156 static GArray *gpollfds;
158 int qemu_init_main_loop(Error **errp)
160 int ret;
161 GSource *src;
163 init_clocks(qemu_timer_notify_cb);
165 ret = qemu_signal_init(errp);
166 if (ret) {
167 return ret;
170 qemu_aio_context = aio_context_new(errp);
171 if (!qemu_aio_context) {
172 return -EMFILE;
174 qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL);
175 gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
176 src = aio_get_g_source(qemu_aio_context);
177 g_source_set_name(src, "aio-context");
178 g_source_attach(src, NULL);
179 g_source_unref(src);
180 src = iohandler_get_g_source();
181 g_source_set_name(src, "io-handler");
182 g_source_attach(src, NULL);
183 g_source_unref(src);
184 return 0;
187 static int max_priority;
189 #ifndef _WIN32
190 static int glib_pollfds_idx;
191 static int glib_n_poll_fds;
193 void qemu_fd_register(int fd)
197 static void glib_pollfds_fill(int64_t *cur_timeout)
199 GMainContext *context = g_main_context_default();
200 int timeout = 0;
201 int64_t timeout_ns;
202 int n;
204 g_main_context_prepare(context, &max_priority);
206 glib_pollfds_idx = gpollfds->len;
207 n = glib_n_poll_fds;
208 do {
209 GPollFD *pfds;
210 glib_n_poll_fds = n;
211 g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
212 pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
213 n = g_main_context_query(context, max_priority, &timeout, pfds,
214 glib_n_poll_fds);
215 } while (n != glib_n_poll_fds);
217 if (timeout < 0) {
218 timeout_ns = -1;
219 } else {
220 timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
223 *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
226 static void glib_pollfds_poll(void)
228 GMainContext *context = g_main_context_default();
229 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
231 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
232 g_main_context_dispatch(context);
236 #define MAX_MAIN_LOOP_SPIN (1000)
238 static int os_host_main_loop_wait(int64_t timeout)
240 GMainContext *context = g_main_context_default();
241 int ret;
243 g_main_context_acquire(context);
245 glib_pollfds_fill(&timeout);
247 qemu_mutex_unlock_iothread();
248 replay_mutex_unlock();
250 ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
252 replay_mutex_lock();
253 qemu_mutex_lock_iothread();
255 glib_pollfds_poll();
257 g_main_context_release(context);
259 return ret;
261 #else
262 /***********************************************************/
263 /* Polling handling */
265 typedef struct PollingEntry {
266 PollingFunc *func;
267 void *opaque;
268 struct PollingEntry *next;
269 } PollingEntry;
271 static PollingEntry *first_polling_entry;
273 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
275 PollingEntry **ppe, *pe;
276 pe = g_malloc0(sizeof(PollingEntry));
277 pe->func = func;
278 pe->opaque = opaque;
279 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
280 *ppe = pe;
281 return 0;
284 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
286 PollingEntry **ppe, *pe;
287 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
288 pe = *ppe;
289 if (pe->func == func && pe->opaque == opaque) {
290 *ppe = pe->next;
291 g_free(pe);
292 break;
297 /***********************************************************/
298 /* Wait objects support */
299 typedef struct WaitObjects {
300 int num;
301 int revents[MAXIMUM_WAIT_OBJECTS + 1];
302 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
303 WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
304 void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
305 } WaitObjects;
307 static WaitObjects wait_objects = {0};
309 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
311 WaitObjects *w = &wait_objects;
312 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
313 return -1;
315 w->events[w->num] = handle;
316 w->func[w->num] = func;
317 w->opaque[w->num] = opaque;
318 w->revents[w->num] = 0;
319 w->num++;
320 return 0;
323 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
325 int i, found;
326 WaitObjects *w = &wait_objects;
328 found = 0;
329 for (i = 0; i < w->num; i++) {
330 if (w->events[i] == handle) {
331 found = 1;
333 if (found) {
334 w->events[i] = w->events[i + 1];
335 w->func[i] = w->func[i + 1];
336 w->opaque[i] = w->opaque[i + 1];
337 w->revents[i] = w->revents[i + 1];
340 if (found) {
341 w->num--;
345 void qemu_fd_register(int fd)
347 WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
348 FD_READ | FD_ACCEPT | FD_CLOSE |
349 FD_CONNECT | FD_WRITE | FD_OOB);
352 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
353 fd_set *xfds)
355 int nfds = -1;
356 int i;
358 for (i = 0; i < pollfds->len; i++) {
359 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
360 int fd = pfd->fd;
361 int events = pfd->events;
362 if (events & G_IO_IN) {
363 FD_SET(fd, rfds);
364 nfds = MAX(nfds, fd);
366 if (events & G_IO_OUT) {
367 FD_SET(fd, wfds);
368 nfds = MAX(nfds, fd);
370 if (events & G_IO_PRI) {
371 FD_SET(fd, xfds);
372 nfds = MAX(nfds, fd);
375 return nfds;
378 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
379 fd_set *wfds, fd_set *xfds)
381 int i;
383 for (i = 0; i < pollfds->len; i++) {
384 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
385 int fd = pfd->fd;
386 int revents = 0;
388 if (FD_ISSET(fd, rfds)) {
389 revents |= G_IO_IN;
391 if (FD_ISSET(fd, wfds)) {
392 revents |= G_IO_OUT;
394 if (FD_ISSET(fd, xfds)) {
395 revents |= G_IO_PRI;
397 pfd->revents = revents & pfd->events;
401 static int os_host_main_loop_wait(int64_t timeout)
403 GMainContext *context = g_main_context_default();
404 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
405 int select_ret = 0;
406 int g_poll_ret, ret, i, n_poll_fds;
407 PollingEntry *pe;
408 WaitObjects *w = &wait_objects;
409 gint poll_timeout;
410 int64_t poll_timeout_ns;
411 static struct timeval tv0;
412 fd_set rfds, wfds, xfds;
413 int nfds;
415 g_main_context_acquire(context);
417 /* XXX: need to suppress polling by better using win32 events */
418 ret = 0;
419 for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
420 ret |= pe->func(pe->opaque);
422 if (ret != 0) {
423 g_main_context_release(context);
424 return ret;
427 FD_ZERO(&rfds);
428 FD_ZERO(&wfds);
429 FD_ZERO(&xfds);
430 nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
431 if (nfds >= 0) {
432 select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
433 if (select_ret != 0) {
434 timeout = 0;
436 if (select_ret > 0) {
437 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
441 g_main_context_prepare(context, &max_priority);
442 n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
443 poll_fds, ARRAY_SIZE(poll_fds));
444 g_assert(n_poll_fds + w->num <= ARRAY_SIZE(poll_fds));
446 for (i = 0; i < w->num; i++) {
447 poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
448 poll_fds[n_poll_fds + i].events = G_IO_IN;
451 if (poll_timeout < 0) {
452 poll_timeout_ns = -1;
453 } else {
454 poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
457 poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
459 qemu_mutex_unlock_iothread();
461 replay_mutex_unlock();
463 g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
465 replay_mutex_lock();
467 qemu_mutex_lock_iothread();
468 if (g_poll_ret > 0) {
469 for (i = 0; i < w->num; i++) {
470 w->revents[i] = poll_fds[n_poll_fds + i].revents;
472 for (i = 0; i < w->num; i++) {
473 if (w->revents[i] && w->func[i]) {
474 w->func[i](w->opaque[i]);
479 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
480 g_main_context_dispatch(context);
483 g_main_context_release(context);
485 return select_ret || g_poll_ret;
487 #endif
489 static NotifierList main_loop_poll_notifiers =
490 NOTIFIER_LIST_INITIALIZER(main_loop_poll_notifiers);
492 void main_loop_poll_add_notifier(Notifier *notify)
494 notifier_list_add(&main_loop_poll_notifiers, notify);
497 void main_loop_poll_remove_notifier(Notifier *notify)
499 notifier_remove(notify);
502 void main_loop_wait(int nonblocking)
504 MainLoopPoll mlpoll = {
505 .state = MAIN_LOOP_POLL_FILL,
506 .timeout = UINT32_MAX,
507 .pollfds = gpollfds,
509 int ret;
510 int64_t timeout_ns;
512 if (nonblocking) {
513 mlpoll.timeout = 0;
516 /* poll any events */
517 g_array_set_size(gpollfds, 0); /* reset for new iteration */
518 /* XXX: separate device handlers from system ones */
519 notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
521 if (mlpoll.timeout == UINT32_MAX) {
522 timeout_ns = -1;
523 } else {
524 timeout_ns = (uint64_t)mlpoll.timeout * (int64_t)(SCALE_MS);
527 timeout_ns = qemu_soonest_timeout(timeout_ns,
528 timerlistgroup_deadline_ns(
529 &main_loop_tlg));
531 ret = os_host_main_loop_wait(timeout_ns);
532 mlpoll.state = ret < 0 ? MAIN_LOOP_POLL_ERR : MAIN_LOOP_POLL_OK;
533 notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
535 if (icount_enabled()) {
537 * CPU thread can infinitely wait for event after
538 * missing the warp
540 icount_start_warp_timer();
542 qemu_clock_run_all_timers();
545 /* Functions to operate on the main QEMU AioContext. */
547 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
549 return aio_bh_new(qemu_aio_context, cb, opaque);
553 * Functions to operate on the I/O handler AioContext.
554 * This context runs on top of main loop. We can't reuse qemu_aio_context
555 * because iohandlers mustn't be polled by aio_poll(qemu_aio_context).
557 static AioContext *iohandler_ctx;
559 static void iohandler_init(void)
561 if (!iohandler_ctx) {
562 iohandler_ctx = aio_context_new(&error_abort);
566 AioContext *iohandler_get_aio_context(void)
568 iohandler_init();
569 return iohandler_ctx;
572 GSource *iohandler_get_g_source(void)
574 iohandler_init();
575 return aio_get_g_source(iohandler_ctx);
578 void qemu_set_fd_handler(int fd,
579 IOHandler *fd_read,
580 IOHandler *fd_write,
581 void *opaque)
583 iohandler_init();
584 aio_set_fd_handler(iohandler_ctx, fd, false,
585 fd_read, fd_write, NULL, opaque);
588 void event_notifier_set_handler(EventNotifier *e,
589 EventNotifierHandler *handler)
591 iohandler_init();
592 aio_set_event_notifier(iohandler_ctx, e, false,
593 handler, NULL);
596 /* reaping of zombies. right now we're not passing the status to
597 anyone, but it would be possible to add a callback. */
598 #ifndef _WIN32
599 typedef struct ChildProcessRecord {
600 int pid;
601 QLIST_ENTRY(ChildProcessRecord) next;
602 } ChildProcessRecord;
604 static QLIST_HEAD(, ChildProcessRecord) child_watches =
605 QLIST_HEAD_INITIALIZER(child_watches);
607 static QEMUBH *sigchld_bh;
609 static void sigchld_handler(int signal)
611 qemu_bh_schedule(sigchld_bh);
614 static void sigchld_bh_handler(void *opaque)
616 ChildProcessRecord *rec, *next;
618 QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
619 if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
620 QLIST_REMOVE(rec, next);
621 g_free(rec);
626 static void qemu_init_child_watch(void)
628 struct sigaction act;
629 sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
631 memset(&act, 0, sizeof(act));
632 act.sa_handler = sigchld_handler;
633 act.sa_flags = SA_NOCLDSTOP;
634 sigaction(SIGCHLD, &act, NULL);
637 int qemu_add_child_watch(pid_t pid)
639 ChildProcessRecord *rec;
641 if (!sigchld_bh) {
642 qemu_init_child_watch();
645 QLIST_FOREACH(rec, &child_watches, next) {
646 if (rec->pid == pid) {
647 return 1;
650 rec = g_malloc0(sizeof(ChildProcessRecord));
651 rec->pid = pid;
652 QLIST_INSERT_HEAD(&child_watches, rec, next);
653 return 0;
655 #endif