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