Merge remote-tracking branch 'remotes/dgilbert-gitlab/tags/pull-virtiofs-20210315...
[qemu/ar7.git] / util / main-loop.c
blob5188ff65407b3caba5216eb576c322a898b8b4d1
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/cpu-timers.h"
30 #include "sysemu/replay.h"
31 #include "qemu/main-loop.h"
32 #include "block/aio.h"
33 #include "qemu/error-report.h"
34 #include "qemu/queue.h"
35 #include "qemu/compiler.h"
37 #ifndef _WIN32
38 #include <sys/wait.h>
39 #endif
41 #ifndef _WIN32
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.
48 * Disable CFI checks.
49 * We are going to call a signal hander directly. Such handler may or may not
50 * have been defined in our binary, so there's no guarantee that the pointer
51 * used to set the handler is a cfi-valid pointer. Since the handlers are
52 * stored in kernel memory, changing the handler to an attacker-defined
53 * function requires being able to call a sigaction() syscall,
54 * which is not as easy as overwriting a pointer in memory.
56 QEMU_DISABLE_CFI
57 static void sigfd_handler(void *opaque)
59 int fd = (intptr_t)opaque;
60 struct qemu_signalfd_siginfo info;
61 struct sigaction action;
62 ssize_t len;
64 while (1) {
65 do {
66 len = read(fd, &info, sizeof(info));
67 } while (len == -1 && errno == EINTR);
69 if (len == -1 && errno == EAGAIN) {
70 break;
73 if (len != sizeof(info)) {
74 error_report("read from sigfd returned %zd: %s", len,
75 g_strerror(errno));
76 return;
79 sigaction(info.ssi_signo, NULL, &action);
80 if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
81 sigaction_invoke(&action, &info);
82 } else if (action.sa_handler) {
83 action.sa_handler(info.ssi_signo);
88 static int qemu_signal_init(Error **errp)
90 int sigfd;
91 sigset_t set;
94 * SIG_IPI must be blocked in the main thread and must not be caught
95 * by sigwait() in the signal thread. Otherwise, the cpu thread will
96 * not catch it reliably.
98 sigemptyset(&set);
99 sigaddset(&set, SIG_IPI);
100 sigaddset(&set, SIGIO);
101 sigaddset(&set, SIGALRM);
102 sigaddset(&set, SIGBUS);
103 /* SIGINT cannot be handled via signalfd, so that ^C can be used
104 * to interrupt QEMU when it is being run under gdb. SIGHUP and
105 * SIGTERM are also handled asynchronously, even though it is not
106 * strictly necessary, because they use the same handler as SIGINT.
108 pthread_sigmask(SIG_BLOCK, &set, NULL);
110 sigdelset(&set, SIG_IPI);
111 sigfd = qemu_signalfd(&set);
112 if (sigfd == -1) {
113 error_setg_errno(errp, errno, "failed to create signalfd");
114 return -errno;
117 fcntl_setfl(sigfd, O_NONBLOCK);
119 qemu_set_fd_handler(sigfd, sigfd_handler, NULL, (void *)(intptr_t)sigfd);
121 return 0;
124 #else /* _WIN32 */
126 static int qemu_signal_init(Error **errp)
128 return 0;
130 #endif
132 static AioContext *qemu_aio_context;
133 static QEMUBH *qemu_notify_bh;
135 static void notify_event_cb(void *opaque)
137 /* No need to do anything; this bottom half is only used to
138 * kick the kernel out of ppoll/poll/WaitForMultipleObjects.
142 AioContext *qemu_get_aio_context(void)
144 return qemu_aio_context;
147 void qemu_notify_event(void)
149 if (!qemu_aio_context) {
150 return;
152 qemu_bh_schedule(qemu_notify_bh);
155 static GArray *gpollfds;
157 int qemu_init_main_loop(Error **errp)
159 int ret;
160 GSource *src;
162 init_clocks(qemu_timer_notify_cb);
164 ret = qemu_signal_init(errp);
165 if (ret) {
166 return ret;
169 qemu_aio_context = aio_context_new(errp);
170 if (!qemu_aio_context) {
171 return -EMFILE;
173 qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL);
174 gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
175 src = aio_get_g_source(qemu_aio_context);
176 g_source_set_name(src, "aio-context");
177 g_source_attach(src, NULL);
178 g_source_unref(src);
179 src = iohandler_get_g_source();
180 g_source_set_name(src, "io-handler");
181 g_source_attach(src, NULL);
182 g_source_unref(src);
183 return 0;
186 static int max_priority;
188 #ifndef _WIN32
189 static int glib_pollfds_idx;
190 static int glib_n_poll_fds;
192 void qemu_fd_register(int fd)
196 static void glib_pollfds_fill(int64_t *cur_timeout)
198 GMainContext *context = g_main_context_default();
199 int timeout = 0;
200 int64_t timeout_ns;
201 int n;
203 g_main_context_prepare(context, &max_priority);
205 glib_pollfds_idx = gpollfds->len;
206 n = glib_n_poll_fds;
207 do {
208 GPollFD *pfds;
209 glib_n_poll_fds = n;
210 g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
211 pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
212 n = g_main_context_query(context, max_priority, &timeout, pfds,
213 glib_n_poll_fds);
214 } while (n != glib_n_poll_fds);
216 if (timeout < 0) {
217 timeout_ns = -1;
218 } else {
219 timeout_ns = (int64_t)timeout * (int64_t)SCALE_MS;
222 *cur_timeout = qemu_soonest_timeout(timeout_ns, *cur_timeout);
225 static void glib_pollfds_poll(void)
227 GMainContext *context = g_main_context_default();
228 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
230 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
231 g_main_context_dispatch(context);
235 #define MAX_MAIN_LOOP_SPIN (1000)
237 static int os_host_main_loop_wait(int64_t timeout)
239 GMainContext *context = g_main_context_default();
240 int ret;
242 g_main_context_acquire(context);
244 glib_pollfds_fill(&timeout);
246 qemu_mutex_unlock_iothread();
247 replay_mutex_unlock();
249 ret = qemu_poll_ns((GPollFD *)gpollfds->data, gpollfds->len, timeout);
251 replay_mutex_lock();
252 qemu_mutex_lock_iothread();
254 glib_pollfds_poll();
256 g_main_context_release(context);
258 return ret;
260 #else
261 /***********************************************************/
262 /* Polling handling */
264 typedef struct PollingEntry {
265 PollingFunc *func;
266 void *opaque;
267 struct PollingEntry *next;
268 } PollingEntry;
270 static PollingEntry *first_polling_entry;
272 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
274 PollingEntry **ppe, *pe;
275 pe = g_malloc0(sizeof(PollingEntry));
276 pe->func = func;
277 pe->opaque = opaque;
278 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
279 *ppe = pe;
280 return 0;
283 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
285 PollingEntry **ppe, *pe;
286 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
287 pe = *ppe;
288 if (pe->func == func && pe->opaque == opaque) {
289 *ppe = pe->next;
290 g_free(pe);
291 break;
296 /***********************************************************/
297 /* Wait objects support */
298 typedef struct WaitObjects {
299 int num;
300 int revents[MAXIMUM_WAIT_OBJECTS + 1];
301 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
302 WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
303 void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
304 } WaitObjects;
306 static WaitObjects wait_objects = {0};
308 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
310 WaitObjects *w = &wait_objects;
311 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
312 return -1;
314 w->events[w->num] = handle;
315 w->func[w->num] = func;
316 w->opaque[w->num] = opaque;
317 w->revents[w->num] = 0;
318 w->num++;
319 return 0;
322 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
324 int i, found;
325 WaitObjects *w = &wait_objects;
327 found = 0;
328 for (i = 0; i < w->num; i++) {
329 if (w->events[i] == handle) {
330 found = 1;
332 if (found) {
333 w->events[i] = w->events[i + 1];
334 w->func[i] = w->func[i + 1];
335 w->opaque[i] = w->opaque[i + 1];
336 w->revents[i] = w->revents[i + 1];
339 if (found) {
340 w->num--;
344 void qemu_fd_register(int fd)
346 WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
347 FD_READ | FD_ACCEPT | FD_CLOSE |
348 FD_CONNECT | FD_WRITE | FD_OOB);
351 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
352 fd_set *xfds)
354 int nfds = -1;
355 int i;
357 for (i = 0; i < pollfds->len; i++) {
358 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
359 int fd = pfd->fd;
360 int events = pfd->events;
361 if (events & G_IO_IN) {
362 FD_SET(fd, rfds);
363 nfds = MAX(nfds, fd);
365 if (events & G_IO_OUT) {
366 FD_SET(fd, wfds);
367 nfds = MAX(nfds, fd);
369 if (events & G_IO_PRI) {
370 FD_SET(fd, xfds);
371 nfds = MAX(nfds, fd);
374 return nfds;
377 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
378 fd_set *wfds, fd_set *xfds)
380 int i;
382 for (i = 0; i < pollfds->len; i++) {
383 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
384 int fd = pfd->fd;
385 int revents = 0;
387 if (FD_ISSET(fd, rfds)) {
388 revents |= G_IO_IN;
390 if (FD_ISSET(fd, wfds)) {
391 revents |= G_IO_OUT;
393 if (FD_ISSET(fd, xfds)) {
394 revents |= G_IO_PRI;
396 pfd->revents = revents & pfd->events;
400 static int os_host_main_loop_wait(int64_t timeout)
402 GMainContext *context = g_main_context_default();
403 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
404 int select_ret = 0;
405 int g_poll_ret, ret, i, n_poll_fds;
406 PollingEntry *pe;
407 WaitObjects *w = &wait_objects;
408 gint poll_timeout;
409 int64_t poll_timeout_ns;
410 static struct timeval tv0;
411 fd_set rfds, wfds, xfds;
412 int nfds;
414 g_main_context_acquire(context);
416 /* XXX: need to suppress polling by better using win32 events */
417 ret = 0;
418 for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
419 ret |= pe->func(pe->opaque);
421 if (ret != 0) {
422 g_main_context_release(context);
423 return ret;
426 FD_ZERO(&rfds);
427 FD_ZERO(&wfds);
428 FD_ZERO(&xfds);
429 nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
430 if (nfds >= 0) {
431 select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
432 if (select_ret != 0) {
433 timeout = 0;
435 if (select_ret > 0) {
436 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
440 g_main_context_prepare(context, &max_priority);
441 n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
442 poll_fds, ARRAY_SIZE(poll_fds));
443 g_assert(n_poll_fds + w->num <= ARRAY_SIZE(poll_fds));
445 for (i = 0; i < w->num; i++) {
446 poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
447 poll_fds[n_poll_fds + i].events = G_IO_IN;
450 if (poll_timeout < 0) {
451 poll_timeout_ns = -1;
452 } else {
453 poll_timeout_ns = (int64_t)poll_timeout * (int64_t)SCALE_MS;
456 poll_timeout_ns = qemu_soonest_timeout(poll_timeout_ns, timeout);
458 qemu_mutex_unlock_iothread();
460 replay_mutex_unlock();
462 g_poll_ret = qemu_poll_ns(poll_fds, n_poll_fds + w->num, poll_timeout_ns);
464 replay_mutex_lock();
466 qemu_mutex_lock_iothread();
467 if (g_poll_ret > 0) {
468 for (i = 0; i < w->num; i++) {
469 w->revents[i] = poll_fds[n_poll_fds + i].revents;
471 for (i = 0; i < w->num; i++) {
472 if (w->revents[i] && w->func[i]) {
473 w->func[i](w->opaque[i]);
478 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
479 g_main_context_dispatch(context);
482 g_main_context_release(context);
484 return select_ret || g_poll_ret;
486 #endif
488 static NotifierList main_loop_poll_notifiers =
489 NOTIFIER_LIST_INITIALIZER(main_loop_poll_notifiers);
491 void main_loop_poll_add_notifier(Notifier *notify)
493 notifier_list_add(&main_loop_poll_notifiers, notify);
496 void main_loop_poll_remove_notifier(Notifier *notify)
498 notifier_remove(notify);
501 void main_loop_wait(int nonblocking)
503 MainLoopPoll mlpoll = {
504 .state = MAIN_LOOP_POLL_FILL,
505 .timeout = UINT32_MAX,
506 .pollfds = gpollfds,
508 int ret;
509 int64_t timeout_ns;
511 if (nonblocking) {
512 mlpoll.timeout = 0;
515 /* poll any events */
516 g_array_set_size(gpollfds, 0); /* reset for new iteration */
517 /* XXX: separate device handlers from system ones */
518 notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
520 if (mlpoll.timeout == UINT32_MAX) {
521 timeout_ns = -1;
522 } else {
523 timeout_ns = (uint64_t)mlpoll.timeout * (int64_t)(SCALE_MS);
526 timeout_ns = qemu_soonest_timeout(timeout_ns,
527 timerlistgroup_deadline_ns(
528 &main_loop_tlg));
530 ret = os_host_main_loop_wait(timeout_ns);
531 mlpoll.state = ret < 0 ? MAIN_LOOP_POLL_ERR : MAIN_LOOP_POLL_OK;
532 notifier_list_notify(&main_loop_poll_notifiers, &mlpoll);
534 if (icount_enabled()) {
536 * CPU thread can infinitely wait for event after
537 * missing the warp
539 icount_start_warp_timer();
541 qemu_clock_run_all_timers();
544 /* Functions to operate on the main QEMU AioContext. */
546 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
548 return aio_bh_new(qemu_aio_context, cb, opaque);
552 * Functions to operate on the I/O handler AioContext.
553 * This context runs on top of main loop. We can't reuse qemu_aio_context
554 * because iohandlers mustn't be polled by aio_poll(qemu_aio_context).
556 static AioContext *iohandler_ctx;
558 static void iohandler_init(void)
560 if (!iohandler_ctx) {
561 iohandler_ctx = aio_context_new(&error_abort);
565 AioContext *iohandler_get_aio_context(void)
567 iohandler_init();
568 return iohandler_ctx;
571 GSource *iohandler_get_g_source(void)
573 iohandler_init();
574 return aio_get_g_source(iohandler_ctx);
577 void qemu_set_fd_handler(int fd,
578 IOHandler *fd_read,
579 IOHandler *fd_write,
580 void *opaque)
582 iohandler_init();
583 aio_set_fd_handler(iohandler_ctx, fd, false,
584 fd_read, fd_write, NULL, opaque);
587 void event_notifier_set_handler(EventNotifier *e,
588 EventNotifierHandler *handler)
590 iohandler_init();
591 aio_set_event_notifier(iohandler_ctx, e, false,
592 handler, NULL);
595 /* reaping of zombies. right now we're not passing the status to
596 anyone, but it would be possible to add a callback. */
597 #ifndef _WIN32
598 typedef struct ChildProcessRecord {
599 int pid;
600 QLIST_ENTRY(ChildProcessRecord) next;
601 } ChildProcessRecord;
603 static QLIST_HEAD(, ChildProcessRecord) child_watches =
604 QLIST_HEAD_INITIALIZER(child_watches);
606 static QEMUBH *sigchld_bh;
608 static void sigchld_handler(int signal)
610 qemu_bh_schedule(sigchld_bh);
613 static void sigchld_bh_handler(void *opaque)
615 ChildProcessRecord *rec, *next;
617 QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
618 if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
619 QLIST_REMOVE(rec, next);
620 g_free(rec);
625 static void qemu_init_child_watch(void)
627 struct sigaction act;
628 sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
630 memset(&act, 0, sizeof(act));
631 act.sa_handler = sigchld_handler;
632 act.sa_flags = SA_NOCLDSTOP;
633 sigaction(SIGCHLD, &act, NULL);
636 int qemu_add_child_watch(pid_t pid)
638 ChildProcessRecord *rec;
640 if (!sigchld_bh) {
641 qemu_init_child_watch();
644 QLIST_FOREACH(rec, &child_watches, next) {
645 if (rec->pid == pid) {
646 return 1;
649 rec = g_malloc0(sizeof(ChildProcessRecord));
650 rec->pid = pid;
651 QLIST_INSERT_HEAD(&child_watches, rec, next);
652 return 0;
654 #endif