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     if (init_timer_alarm() < 0) {
 127         fprintf(stderr, "could not initialize alarm timer\n");
 128         exit(1);
 129     }
 130
 131     qemu_mutex_lock_iothread();
 132     ret = qemu_signal_init();
 133     if (ret) {
 134         return ret;
 135     }
 136
 137     qemu_aio_context = aio_context_new();
 138     src = aio_get_g_source(qemu_aio_context);
 139     g_source_attach(src, NULL);
 140     g_source_unref(src);
 141     return 0;
 142 }
 143
 144 static fd_set rfds, wfds, xfds;
 145 static int nfds;
 146 static GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
 147 static int n_poll_fds;
 148 static int max_priority;
 149
 150 #ifndef _WIN32
 151 static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds,
 152                              fd_set *xfds, uint32_t *cur_timeout)
 153 {
 154     GMainContext *context = g_main_context_default();
 155     int i;
 156     int timeout = 0;
 157
 158     g_main_context_prepare(context, &max_priority);
 159
 160     n_poll_fds = g_main_context_query(context, max_priority, &timeout,
 161                                       poll_fds, ARRAY_SIZE(poll_fds));
 162     g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
 163
 164     for (i = 0; i < n_poll_fds; i++) {
 165         GPollFD *p = &poll_fds[i];
 166
 167         if ((p->events & G_IO_IN)) {
 168             FD_SET(p->fd, rfds);
 169             *max_fd = MAX(*max_fd, p->fd);
 170         }
 171         if ((p->events & G_IO_OUT)) {
 172             FD_SET(p->fd, wfds);
 173             *max_fd = MAX(*max_fd, p->fd);
 174         }
 175         if ((p->events & G_IO_ERR)) {
 176             FD_SET(p->fd, xfds);
 177             *max_fd = MAX(*max_fd, p->fd);
 178         }
 179     }
 180
 181     if (timeout >= 0 && timeout < *cur_timeout) {
 182         *cur_timeout = timeout;
 183     }
 184 }
 185
 186 static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds,
 187                              bool err)
 188 {
 189     GMainContext *context = g_main_context_default();
 190
 191     if (!err) {
 192         int i;
 193
 194         for (i = 0; i < n_poll_fds; i++) {
 195             GPollFD *p = &poll_fds[i];
 196
 197             if ((p->events & G_IO_IN) && FD_ISSET(p->fd, rfds)) {
 198                 p->revents |= G_IO_IN;
 199             }
 200             if ((p->events & G_IO_OUT) && FD_ISSET(p->fd, wfds)) {
 201                 p->revents |= G_IO_OUT;
 202             }
 203             if ((p->events & G_IO_ERR) && FD_ISSET(p->fd, xfds)) {
 204                 p->revents |= G_IO_ERR;
 205             }
 206         }
 207     }
 208
 209     if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
 210         g_main_context_dispatch(context);
 211     }
 212 }
 213
 214 static int os_host_main_loop_wait(uint32_t timeout)
 215 {
 216     struct timeval tv, *tvarg = NULL;
 217     int ret;
 218
 219     glib_select_fill(&nfds, &rfds, &wfds, &xfds, &timeout);
 220
 221     if (timeout < UINT32_MAX) {
 222         tvarg = &tv;
 223         tv.tv_sec = timeout / 1000;
 224         tv.tv_usec = (timeout % 1000) * 1000;
 225     }
 226
 227     if (timeout > 0) {
 228         qemu_mutex_unlock_iothread();
 229     }
 230
 231     ret = select(nfds + 1, &rfds, &wfds, &xfds, tvarg);
 232
 233     if (timeout > 0) {
 234         qemu_mutex_lock_iothread();
 235     }
 236
 237     glib_select_poll(&rfds, &wfds, &xfds, (ret < 0));
 238     return ret;
 239 }
 240 #else
 241 /***********************************************************/
 242 /* Polling handling */
 243
 244 typedef struct PollingEntry {
 245     PollingFunc *func;
 246     void *opaque;
 247     struct PollingEntry *next;
 248 } PollingEntry;
 249
 250 static PollingEntry *first_polling_entry;
 251
 252 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
 253 {
 254     PollingEntry **ppe, *pe;
 255     pe = g_malloc0(sizeof(PollingEntry));
 256     pe->func = func;
 257     pe->opaque = opaque;
 258     for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
 259     *ppe = pe;
 260     return 0;
 261 }
 262
 263 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
 264 {
 265     PollingEntry **ppe, *pe;
 266     for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
 267         pe = *ppe;
 268         if (pe->func == func && pe->opaque == opaque) {
 269             *ppe = pe->next;
 270             g_free(pe);
 271             break;
 272         }
 273     }
 274 }
 275
 276 /***********************************************************/
 277 /* Wait objects support */
 278 typedef struct WaitObjects {
 279     int num;
 280     int revents[MAXIMUM_WAIT_OBJECTS + 1];
 281     HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
 282     WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
 283     void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
 284 } WaitObjects;
 285
 286 static WaitObjects wait_objects = {0};
 287
 288 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 289 {
 290     WaitObjects *w = &wait_objects;
 291     if (w->num >= MAXIMUM_WAIT_OBJECTS) {
 292         return -1;
 293     }
 294     w->events[w->num] = handle;
 295     w->func[w->num] = func;
 296     w->opaque[w->num] = opaque;
 297     w->revents[w->num] = 0;
 298     w->num++;
 299     return 0;
 300 }
 301
 302 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 303 {
 304     int i, found;
 305     WaitObjects *w = &wait_objects;
 306
 307     found = 0;
 308     for (i = 0; i < w->num; i++) {
 309         if (w->events[i] == handle) {
 310             found = 1;
 311         }
 312         if (found) {
 313             w->events[i] = w->events[i + 1];
 314             w->func[i] = w->func[i + 1];
 315             w->opaque[i] = w->opaque[i + 1];
 316             w->revents[i] = w->revents[i + 1];
 317         }
 318     }
 319     if (found) {
 320         w->num--;
 321     }
 322 }
 323
 324 void qemu_fd_register(int fd)
 325 {
 326     WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
 327                    FD_READ | FD_ACCEPT | FD_CLOSE |
 328                    FD_CONNECT | FD_WRITE | FD_OOB);
 329 }
 330
 331 static int os_host_main_loop_wait(uint32_t timeout)
 332 {
 333     GMainContext *context = g_main_context_default();
 334     int ret, i;
 335     PollingEntry *pe;
 336     WaitObjects *w = &wait_objects;
 337     gint poll_timeout;
 338     static struct timeval tv0;
 339
 340     /* XXX: need to suppress polling by better using win32 events */
 341     ret = 0;
 342     for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
 343         ret |= pe->func(pe->opaque);
 344     }
 345     if (ret != 0) {
 346         return ret;
 347     }
 348
 349     if (nfds >= 0) {
 350         ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
 351         if (ret != 0) {
 352             timeout = 0;
 353         }
 354     }
 355
 356     g_main_context_prepare(context, &max_priority);
 357     n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
 358                                       poll_fds, ARRAY_SIZE(poll_fds));
 359     g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
 360
 361     for (i = 0; i < w->num; i++) {
 362         poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];
 363         poll_fds[n_poll_fds + i].events = G_IO_IN;
 364     }
 365
 366     if (poll_timeout < 0 || timeout < poll_timeout) {
 367         poll_timeout = timeout;
 368     }
 369
 370     qemu_mutex_unlock_iothread();
 371     ret = g_poll(poll_fds, n_poll_fds + w->num, poll_timeout);
 372     qemu_mutex_lock_iothread();
 373     if (ret > 0) {
 374         for (i = 0; i < w->num; i++) {
 375             w->revents[i] = poll_fds[n_poll_fds + i].revents;
 376         }
 377         for (i = 0; i < w->num; i++) {
 378             if (w->revents[i] && w->func[i]) {
 379                 w->func[i](w->opaque[i]);
 380             }
 381         }
 382     }
 383
 384     if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
 385         g_main_context_dispatch(context);
 386     }
 387
 388     /* If an edge-triggered socket event occurred, select will return a
 389      * positive result on the next iteration.  We do not need to do anything
 390      * here.
 391      */
 392
 393     return ret;
 394 }
 395 #endif
 396
 397 int main_loop_wait(int nonblocking)
 398 {
 399     int ret;
 400     uint32_t timeout = UINT32_MAX;
 401
 402     if (nonblocking) {
 403         timeout = 0;
 404     }
 405
 406     /* poll any events */
 407     /* XXX: separate device handlers from system ones */
 408     nfds = -1;
 409     FD_ZERO(&rfds);
 410     FD_ZERO(&wfds);
 411     FD_ZERO(&xfds);
 412
 413 #ifdef CONFIG_SLIRP
 414     slirp_update_timeout(&timeout);
 415     slirp_select_fill(&nfds, &rfds, &wfds, &xfds);
 416 #endif
 417     qemu_iohandler_fill(&nfds, &rfds, &wfds, &xfds);
 418     ret = os_host_main_loop_wait(timeout);
 419     qemu_iohandler_poll(&rfds, &wfds, &xfds, ret);
 420 #ifdef CONFIG_SLIRP
 421     slirp_select_poll(&rfds, &wfds, &xfds, (ret < 0));
 422 #endif
 423
 424     qemu_run_all_timers();
 425
 426     return ret;
 427 }
 428
 429 /* Functions to operate on the main QEMU AioContext.  */
 430
 431 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
 432 {
 433     return aio_bh_new(qemu_aio_context, cb, opaque);
 434 }
 435
 436 void qemu_aio_flush(void)
 437 {
 438     aio_flush(qemu_aio_context);
 439 }
 440
 441 bool qemu_aio_wait(void)
 442 {
 443     return aio_poll(qemu_aio_context, true);
 444 }
 445
 446 #ifdef CONFIG_POSIX
 447 void qemu_aio_set_fd_handler(int fd,
 448                              IOHandler *io_read,
 449                              IOHandler *io_write,
 450                              AioFlushHandler *io_flush,
 451                              void *opaque)
 452 {
 453     aio_set_fd_handler(qemu_aio_context, fd, io_read, io_write, io_flush,
 454                        opaque);
 455 }
 456 #endif
 457
 458 void qemu_aio_set_event_notifier(EventNotifier *notifier,
 459                                  EventNotifierHandler *io_read,
 460                                  AioFlushEventNotifierHandler *io_flush)
 461 {
 462     aio_set_event_notifier(qemu_aio_context, notifier, io_read, io_flush);
 463 }