trap signals for "-serial mon:stdio"
[qemu.git] / 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-common.h"
26 #include "qemu/timer.h"
27 #include "qemu/sockets.h" // struct in_addr needed for libslirp.h
28 #include "slirp/libslirp.h"
29 #include "qemu/main-loop.h"
30 #include "block/aio.h"
31
32 #ifndef _WIN32
33
34 #include "qemu/compatfd.h"
35
36 /* If we have signalfd, we mask out the signals we want to handle and then
37 * use signalfd to listen for them. We rely on whatever the current signal
38 * handler is to dispatch the signals when we receive them.
39 */
40 static void sigfd_handler(void *opaque)
41 {
42 int fd = (intptr_t)opaque;
43 struct qemu_signalfd_siginfo info;
44 struct sigaction action;
45 ssize_t len;
46
47 while (1) {
48 do {
49 len = read(fd, &info, sizeof(info));
50 } while (len == -1 && errno == EINTR);
51
52 if (len == -1 && errno == EAGAIN) {
53 break;
54 }
55
56 if (len != sizeof(info)) {
57 printf("read from sigfd returned %zd: %m\n", len);
58 return;
59 }
60
61 sigaction(info.ssi_signo, NULL, &action);
62 if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
63 action.sa_sigaction(info.ssi_signo,
64 (siginfo_t *)&info, NULL);
65 } else if (action.sa_handler) {
66 action.sa_handler(info.ssi_signo);
67 }
68 }
69 }
70
71 static int qemu_signal_init(void)
72 {
73 int sigfd;
74 sigset_t set;
75
76 /*
77 * SIG_IPI must be blocked in the main thread and must not be caught
78 * by sigwait() in the signal thread. Otherwise, the cpu thread will
79 * not catch it reliably.
80 */
81 sigemptyset(&set);
82 sigaddset(&set, SIG_IPI);
83 sigaddset(&set, SIGIO);
84 sigaddset(&set, SIGALRM);
85 sigaddset(&set, SIGBUS);
86 pthread_sigmask(SIG_BLOCK, &set, NULL);
87
88 sigdelset(&set, SIG_IPI);
89 sigfd = qemu_signalfd(&set);
90 if (sigfd == -1) {
91 fprintf(stderr, "failed to create signalfd\n");
92 return -errno;
93 }
94
95 fcntl_setfl(sigfd, O_NONBLOCK);
96
97 qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL,
98 (void *)(intptr_t)sigfd);
99
100 return 0;
101 }
102
103 #else /* _WIN32 */
104
105 static int qemu_signal_init(void)
106 {
107 return 0;
108 }
109 #endif
110
111 static AioContext *qemu_aio_context;
112
113 AioContext *qemu_get_aio_context(void)
114 {
115 return qemu_aio_context;
116 }
117
118 void qemu_notify_event(void)
119 {
120 if (!qemu_aio_context) {
121 return;
122 }
123 aio_notify(qemu_aio_context);
124 }
125
126 static GArray *gpollfds;
127
128 int qemu_init_main_loop(void)
129 {
130 int ret;
131 GSource *src;
132
133 init_clocks();
134 if (init_timer_alarm() < 0) {
135 fprintf(stderr, "could not initialize alarm timer\n");
136 exit(1);
137 }
138
139 ret = qemu_signal_init();
140 if (ret) {
141 return ret;
142 }
143
144 gpollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
145 qemu_aio_context = aio_context_new();
146 src = aio_get_g_source(qemu_aio_context);
147 g_source_attach(src, NULL);
148 g_source_unref(src);
149 return 0;
150 }
151
152 static int max_priority;
153
154 #ifndef _WIN32
155 static int glib_pollfds_idx;
156 static int glib_n_poll_fds;
157
158 static void glib_pollfds_fill(uint32_t *cur_timeout)
159 {
160 GMainContext *context = g_main_context_default();
161 int timeout = 0;
162 int n;
163
164 g_main_context_prepare(context, &max_priority);
165
166 glib_pollfds_idx = gpollfds->len;
167 n = glib_n_poll_fds;
168 do {
169 GPollFD *pfds;
170 glib_n_poll_fds = n;
171 g_array_set_size(gpollfds, glib_pollfds_idx + glib_n_poll_fds);
172 pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
173 n = g_main_context_query(context, max_priority, &timeout, pfds,
174 glib_n_poll_fds);
175 } while (n != glib_n_poll_fds);
176
177 if (timeout >= 0 && timeout < *cur_timeout) {
178 *cur_timeout = timeout;
179 }
180 }
181
182 static void glib_pollfds_poll(void)
183 {
184 GMainContext *context = g_main_context_default();
185 GPollFD *pfds = &g_array_index(gpollfds, GPollFD, glib_pollfds_idx);
186
187 if (g_main_context_check(context, max_priority, pfds, glib_n_poll_fds)) {
188 g_main_context_dispatch(context);
189 }
190 }
191
192 #define MAX_MAIN_LOOP_SPIN (1000)
193
194 static int os_host_main_loop_wait(uint32_t timeout)
195 {
196 int ret;
197 static int spin_counter;
198
199 glib_pollfds_fill(&timeout);
200
201 /* If the I/O thread is very busy or we are incorrectly busy waiting in
202 * the I/O thread, this can lead to starvation of the BQL such that the
203 * VCPU threads never run. To make sure we can detect the later case,
204 * print a message to the screen. If we run into this condition, create
205 * a fake timeout in order to give the VCPU threads a chance to run.
206 */
207 if (spin_counter > MAX_MAIN_LOOP_SPIN) {
208 static bool notified;
209
210 if (!notified) {
211 fprintf(stderr,
212 "main-loop: WARNING: I/O thread spun for %d iterations\n",
213 MAX_MAIN_LOOP_SPIN);
214 notified = true;
215 }
216
217 timeout = 1;
218 }
219
220 if (timeout > 0) {
221 spin_counter = 0;
222 qemu_mutex_unlock_iothread();
223 } else {
224 spin_counter++;
225 }
226
227 ret = g_poll((GPollFD *)gpollfds->data, gpollfds->len, timeout);
228
229 if (timeout > 0) {
230 qemu_mutex_lock_iothread();
231 }
232
233 glib_pollfds_poll();
234 return ret;
235 }
236 #else
237 /***********************************************************/
238 /* Polling handling */
239
240 typedef struct PollingEntry {
241 PollingFunc *func;
242 void *opaque;
243 struct PollingEntry *next;
244 } PollingEntry;
245
246 static PollingEntry *first_polling_entry;
247
248 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
249 {
250 PollingEntry **ppe, *pe;
251 pe = g_malloc0(sizeof(PollingEntry));
252 pe->func = func;
253 pe->opaque = opaque;
254 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
255 *ppe = pe;
256 return 0;
257 }
258
259 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
260 {
261 PollingEntry **ppe, *pe;
262 for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
263 pe = *ppe;
264 if (pe->func == func && pe->opaque == opaque) {
265 *ppe = pe->next;
266 g_free(pe);
267 break;
268 }
269 }
270 }
271
272 /***********************************************************/
273 /* Wait objects support */
274 typedef struct WaitObjects {
275 int num;
276 int revents[MAXIMUM_WAIT_OBJECTS + 1];
277 HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
278 WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
279 void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
280 } WaitObjects;
281
282 static WaitObjects wait_objects = {0};
283
284 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
285 {
286 WaitObjects *w = &wait_objects;
287 if (w->num >= MAXIMUM_WAIT_OBJECTS) {
288 return -1;
289 }
290 w->events[w->num] = handle;
291 w->func[w->num] = func;
292 w->opaque[w->num] = opaque;
293 w->revents[w->num] = 0;
294 w->num++;
295 return 0;
296 }
297
298 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
299 {
300 int i, found;
301 WaitObjects *w = &wait_objects;
302
303 found = 0;
304 for (i = 0; i < w->num; i++) {
305 if (w->events[i] == handle) {
306 found = 1;
307 }
308 if (found) {
309 w->events[i] = w->events[i + 1];
310 w->func[i] = w->func[i + 1];
311 w->opaque[i] = w->opaque[i + 1];
312 w->revents[i] = w->revents[i + 1];
313 }
314 }
315 if (found) {
316 w->num--;
317 }
318 }
319
320 void qemu_fd_register(int fd)
321 {
322 WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
323 FD_READ | FD_ACCEPT | FD_CLOSE |
324 FD_CONNECT | FD_WRITE | FD_OOB);
325 }
326
327 static int pollfds_fill(GArray *pollfds, fd_set *rfds, fd_set *wfds,
328 fd_set *xfds)
329 {
330 int nfds = -1;
331 int i;
332
333 for (i = 0; i < pollfds->len; i++) {
334 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
335 int fd = pfd->fd;
336 int events = pfd->events;
337 if (events & G_IO_IN) {
338 FD_SET(fd, rfds);
339 nfds = MAX(nfds, fd);
340 }
341 if (events & G_IO_OUT) {
342 FD_SET(fd, wfds);
343 nfds = MAX(nfds, fd);
344 }
345 if (events & G_IO_PRI) {
346 FD_SET(fd, xfds);
347 nfds = MAX(nfds, fd);
348 }
349 }
350 return nfds;
351 }
352
353 static void pollfds_poll(GArray *pollfds, int nfds, fd_set *rfds,
354 fd_set *wfds, fd_set *xfds)
355 {
356 int i;
357
358 for (i = 0; i < pollfds->len; i++) {
359 GPollFD *pfd = &g_array_index(pollfds, GPollFD, i);
360 int fd = pfd->fd;
361 int revents = 0;
362
363 if (FD_ISSET(fd, rfds)) {
364 revents |= G_IO_IN;
365 }
366 if (FD_ISSET(fd, wfds)) {
367 revents |= G_IO_OUT;
368 }
369 if (FD_ISSET(fd, xfds)) {
370 revents |= G_IO_PRI;
371 }
372 pfd->revents = revents & pfd->events;
373 }
374 }
375
376 static int os_host_main_loop_wait(uint32_t timeout)
377 {
378 GMainContext *context = g_main_context_default();
379 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
380 int select_ret = 0;
381 int g_poll_ret, ret, i, n_poll_fds;
382 PollingEntry *pe;
383 WaitObjects *w = &wait_objects;
384 gint poll_timeout;
385 static struct timeval tv0;
386 fd_set rfds, wfds, xfds;
387 int nfds;
388
389 /* XXX: need to suppress polling by better using win32 events */
390 ret = 0;
391 for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
392 ret |= pe->func(pe->opaque);
393 }
394 if (ret != 0) {
395 return ret;
396 }
397
398 FD_ZERO(&rfds);
399 FD_ZERO(&wfds);
400 FD_ZERO(&xfds);
401 nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
402 if (nfds >= 0) {
403 select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
404 if (select_ret != 0) {
405 timeout = 0;
406 }
407 if (select_ret > 0) {
408 pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
409 }
410 }
411
412 g_main_context_prepare(context, &max_priority);
413 n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
414 poll_fds, ARRAY_SIZE(poll_fds));
415 g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
416
417 for (i = 0; i < w->num; i++) {
418 poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
419 poll_fds[n_poll_fds + i].events = G_IO_IN;
420 }
421
422 if (poll_timeout < 0 || timeout < poll_timeout) {
423 poll_timeout = timeout;
424 }
425
426 qemu_mutex_unlock_iothread();
427 g_poll_ret = g_poll(poll_fds, n_poll_fds + w->num, poll_timeout);
428 qemu_mutex_lock_iothread();
429 if (g_poll_ret > 0) {
430 for (i = 0; i < w->num; i++) {
431 w->revents[i] = poll_fds[n_poll_fds + i].revents;
432 }
433 for (i = 0; i < w->num; i++) {
434 if (w->revents[i] && w->func[i]) {
435 w->func[i](w->opaque[i]);
436 }
437 }
438 }
439
440 if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
441 g_main_context_dispatch(context);
442 }
443
444 return select_ret || g_poll_ret;
445 }
446 #endif
447
448 int main_loop_wait(int nonblocking)
449 {
450 int ret;
451 uint32_t timeout = UINT32_MAX;
452
453 if (nonblocking) {
454 timeout = 0;
455 }
456
457 /* poll any events */
458 g_array_set_size(gpollfds, 0); /* reset for new iteration */
459 /* XXX: separate device handlers from system ones */
460 #ifdef CONFIG_SLIRP
461 slirp_update_timeout(&timeout);
462 slirp_pollfds_fill(gpollfds);
463 #endif
464 qemu_iohandler_fill(gpollfds);
465 ret = os_host_main_loop_wait(timeout);
466 qemu_iohandler_poll(gpollfds, ret);
467 #ifdef CONFIG_SLIRP
468 slirp_pollfds_poll(gpollfds, (ret < 0));
469 #endif
470
471 qemu_run_all_timers();
472
473 return ret;
474 }
475
476 /* Functions to operate on the main QEMU AioContext. */
477
478 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
479 {
480 return aio_bh_new(qemu_aio_context, cb, opaque);
481 }
482
483 bool qemu_aio_wait(void)
484 {
485 return aio_poll(qemu_aio_context, true);
486 }
487
488 #ifdef CONFIG_POSIX
489 void qemu_aio_set_fd_handler(int fd,
490 IOHandler *io_read,
491 IOHandler *io_write,
492 AioFlushHandler *io_flush,
493 void *opaque)
494 {
495 aio_set_fd_handler(qemu_aio_context, fd, io_read, io_write, io_flush,
496 opaque);
497 }
498 #endif
499
500 void qemu_aio_set_event_notifier(EventNotifier *notifier,
501 EventNotifierHandler *io_read,
502 AioFlushEventNotifierHandler *io_flush)
503 {
504 aio_set_event_notifier(qemu_aio_context, notifier, io_read, io_flush);
505 }