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 #include "config-host.h"
  25 #include <unistd.h>
  26 #include <signal.h>
  27 #include <time.h>
  28 #include <errno.h>
  29 #include <sys/time.h>
  30 #include <stdbool.h>
  31
  32 #ifdef _WIN32
  33 #include <windows.h>
  34 #include <winsock2.h>
  35 #include <ws2tcpip.h>
  36 #else
  37 #include <sys/socket.h>
  38 #include <netinet/in.h>
  39 #include <net/if.h>
  40 #include <arpa/inet.h>
  41 #include <sys/select.h>
  42 #include <sys/stat.h>
  43 #include "compatfd.h"
  44 #endif
  45
  46 #include <glib.h>
  47
  48 #include "main-loop.h"
  49 #include "qemu-timer.h"
  50 #include "slirp/libslirp.h"
  51
  52 #ifndef _WIN32
  53
  54 static int io_thread_fd = -1;
  55
  56 void qemu_notify_event(void)
  57 {
  58     /* Write 8 bytes to be compatible with eventfd.  */
  59     static const uint64_t val = 1;
  60     ssize_t ret;
  61
  62     if (io_thread_fd == -1) {
  63         return;
  64     }
  65     do {
  66         ret = write(io_thread_fd, &val, sizeof(val));
  67     } while (ret < 0 && errno == EINTR);
  68
  69     /* EAGAIN is fine, a read must be pending.  */
  70     if (ret < 0 && errno != EAGAIN) {
  71         fprintf(stderr, "qemu_notify_event: write() failed: %s\n",
  72                 strerror(errno));
  73         exit(1);
  74     }
  75 }
  76
  77 static void qemu_event_read(void *opaque)
  78 {
  79     int fd = (intptr_t)opaque;
  80     ssize_t len;
  81     char buffer[512];
  82
  83     /* Drain the notify pipe.  For eventfd, only 8 bytes will be read.  */
  84     do {
  85         len = read(fd, buffer, sizeof(buffer));
  86     } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
  87 }
  88
  89 static int qemu_event_init(void)
  90 {
  91     int err;
  92     int fds[2];
  93
  94     err = qemu_eventfd(fds);
  95     if (err == -1) {
  96         return -errno;
  97     }
  98     err = fcntl_setfl(fds[0], O_NONBLOCK);
  99     if (err < 0) {
 100         goto fail;
 101     }
 102     err = fcntl_setfl(fds[1], O_NONBLOCK);
 103     if (err < 0) {
 104         goto fail;
 105     }
 106     qemu_set_fd_handler2(fds[0], NULL, qemu_event_read, NULL,
 107                          (void *)(intptr_t)fds[0]);
 108
 109     io_thread_fd = fds[1];
 110     return 0;
 111
 112 fail:
 113     close(fds[0]);
 114     close(fds[1]);
 115     return err;
 116 }
 117
 118 /* If we have signalfd, we mask out the signals we want to handle and then
 119  * use signalfd to listen for them.  We rely on whatever the current signal
 120  * handler is to dispatch the signals when we receive them.
 121  */
 122 static void sigfd_handler(void *opaque)
 123 {
 124     int fd = (intptr_t)opaque;
 125     struct qemu_signalfd_siginfo info;
 126     struct sigaction action;
 127     ssize_t len;
 128
 129     while (1) {
 130         do {
 131             len = read(fd, &info, sizeof(info));
 132         } while (len == -1 && errno == EINTR);
 133
 134         if (len == -1 && errno == EAGAIN) {
 135             break;
 136         }
 137
 138         if (len != sizeof(info)) {
 139             printf("read from sigfd returned %zd: %m\n", len);
 140             return;
 141         }
 142
 143         sigaction(info.ssi_signo, NULL, &action);
 144         if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {
 145             action.sa_sigaction(info.ssi_signo,
 146                                 (siginfo_t *)&info, NULL);
 147         } else if (action.sa_handler) {
 148             action.sa_handler(info.ssi_signo);
 149         }
 150     }
 151 }
 152
 153 static int qemu_signal_init(void)
 154 {
 155     int sigfd;
 156     sigset_t set;
 157
 158     /*
 159      * SIG_IPI must be blocked in the main thread and must not be caught
 160      * by sigwait() in the signal thread. Otherwise, the cpu thread will
 161      * not catch it reliably.
 162      */
 163     sigemptyset(&set);
 164     sigaddset(&set, SIG_IPI);
 165     pthread_sigmask(SIG_BLOCK, &set, NULL);
 166
 167     sigemptyset(&set);
 168     sigaddset(&set, SIGIO);
 169     sigaddset(&set, SIGALRM);
 170     sigaddset(&set, SIGBUS);
 171     pthread_sigmask(SIG_BLOCK, &set, NULL);
 172
 173     sigfd = qemu_signalfd(&set);
 174     if (sigfd == -1) {
 175         fprintf(stderr, "failed to create signalfd\n");
 176         return -errno;
 177     }
 178
 179     fcntl_setfl(sigfd, O_NONBLOCK);
 180
 181     qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL,
 182                          (void *)(intptr_t)sigfd);
 183
 184     return 0;
 185 }
 186
 187 #else /* _WIN32 */
 188
 189 HANDLE qemu_event_handle;
 190
 191 static void dummy_event_handler(void *opaque)
 192 {
 193 }
 194
 195 static int qemu_event_init(void)
 196 {
 197     qemu_event_handle = CreateEvent(NULL, FALSE, FALSE, NULL);
 198     if (!qemu_event_handle) {
 199         fprintf(stderr, "Failed CreateEvent: %ld\n", GetLastError());
 200         return -1;
 201     }
 202     qemu_add_wait_object(qemu_event_handle, dummy_event_handler, NULL);
 203     return 0;
 204 }
 205
 206 void qemu_notify_event(void)
 207 {
 208     if (!SetEvent(qemu_event_handle)) {
 209         fprintf(stderr, "qemu_notify_event: SetEvent failed: %ld\n",
 210                 GetLastError());
 211         exit(1);
 212     }
 213 }
 214
 215 static int qemu_signal_init(void)
 216 {
 217     return 0;
 218 }
 219 #endif
 220
 221 int qemu_init_main_loop(void)
 222 {
 223     int ret;
 224
 225     qemu_mutex_lock_iothread();
 226     ret = qemu_signal_init();
 227     if (ret) {
 228         return ret;
 229     }
 230
 231     /* Note eventfd must be drained before signalfd handlers run */
 232     ret = qemu_event_init();
 233     if (ret) {
 234         return ret;
 235     }
 236
 237     return 0;
 238 }
 239
 240
 241 static GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
 242 static int n_poll_fds;
 243 static int max_priority;
 244
 245 static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds,
 246                              fd_set *xfds, struct timeval *tv)
 247 {
 248     GMainContext *context = g_main_context_default();
 249     int i;
 250     int timeout = 0, cur_timeout;
 251
 252     g_main_context_prepare(context, &max_priority);
 253
 254     n_poll_fds = g_main_context_query(context, max_priority, &timeout,
 255                                       poll_fds, ARRAY_SIZE(poll_fds));
 256     g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));
 257
 258     for (i = 0; i < n_poll_fds; i++) {
 259         GPollFD *p = &poll_fds[i];
 260
 261         if ((p->events & G_IO_IN)) {
 262             FD_SET(p->fd, rfds);
 263             *max_fd = MAX(*max_fd, p->fd);
 264         }
 265         if ((p->events & G_IO_OUT)) {
 266             FD_SET(p->fd, wfds);
 267             *max_fd = MAX(*max_fd, p->fd);
 268         }
 269         if ((p->events & G_IO_ERR)) {
 270             FD_SET(p->fd, xfds);
 271             *max_fd = MAX(*max_fd, p->fd);
 272         }
 273     }
 274
 275     cur_timeout = (tv->tv_sec * 1000) + ((tv->tv_usec + 500) / 1000);
 276     if (timeout >= 0 && timeout < cur_timeout) {
 277         tv->tv_sec = timeout / 1000;
 278         tv->tv_usec = (timeout % 1000) * 1000;
 279     }
 280 }
 281
 282 static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds,
 283                              bool err)
 284 {
 285     GMainContext *context = g_main_context_default();
 286
 287     if (!err) {
 288         int i;
 289
 290         for (i = 0; i < n_poll_fds; i++) {
 291             GPollFD *p = &poll_fds[i];
 292
 293             if ((p->events & G_IO_IN) && FD_ISSET(p->fd, rfds)) {
 294                 p->revents |= G_IO_IN;
 295             }
 296             if ((p->events & G_IO_OUT) && FD_ISSET(p->fd, wfds)) {
 297                 p->revents |= G_IO_OUT;
 298             }
 299             if ((p->events & G_IO_ERR) && FD_ISSET(p->fd, xfds)) {
 300                 p->revents |= G_IO_ERR;
 301             }
 302         }
 303     }
 304
 305     if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {
 306         g_main_context_dispatch(context);
 307     }
 308 }
 309
 310 #ifdef _WIN32
 311 /***********************************************************/
 312 /* Polling handling */
 313
 314 typedef struct PollingEntry {
 315     PollingFunc *func;
 316     void *opaque;
 317     struct PollingEntry *next;
 318 } PollingEntry;
 319
 320 static PollingEntry *first_polling_entry;
 321
 322 int qemu_add_polling_cb(PollingFunc *func, void *opaque)
 323 {
 324     PollingEntry **ppe, *pe;
 325     pe = g_malloc0(sizeof(PollingEntry));
 326     pe->func = func;
 327     pe->opaque = opaque;
 328     for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);
 329     *ppe = pe;
 330     return 0;
 331 }
 332
 333 void qemu_del_polling_cb(PollingFunc *func, void *opaque)
 334 {
 335     PollingEntry **ppe, *pe;
 336     for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {
 337         pe = *ppe;
 338         if (pe->func == func && pe->opaque == opaque) {
 339             *ppe = pe->next;
 340             g_free(pe);
 341             break;
 342         }
 343     }
 344 }
 345
 346 /***********************************************************/
 347 /* Wait objects support */
 348 typedef struct WaitObjects {
 349     int num;
 350     HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];
 351     WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];
 352     void *opaque[MAXIMUM_WAIT_OBJECTS + 1];
 353 } WaitObjects;
 354
 355 static WaitObjects wait_objects = {0};
 356
 357 int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 358 {
 359     WaitObjects *w = &wait_objects;
 360     if (w->num >= MAXIMUM_WAIT_OBJECTS) {
 361         return -1;
 362     }
 363     w->events[w->num] = handle;
 364     w->func[w->num] = func;
 365     w->opaque[w->num] = opaque;
 366     w->num++;
 367     return 0;
 368 }
 369
 370 void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 371 {
 372     int i, found;
 373     WaitObjects *w = &wait_objects;
 374
 375     found = 0;
 376     for (i = 0; i < w->num; i++) {
 377         if (w->events[i] == handle) {
 378             found = 1;
 379         }
 380         if (found) {
 381             w->events[i] = w->events[i + 1];
 382             w->func[i] = w->func[i + 1];
 383             w->opaque[i] = w->opaque[i + 1];
 384         }
 385     }
 386     if (found) {
 387         w->num--;
 388     }
 389 }
 390
 391 static void os_host_main_loop_wait(int *timeout)
 392 {
 393     int ret, ret2, i;
 394     PollingEntry *pe;
 395
 396     /* XXX: need to suppress polling by better using win32 events */
 397     ret = 0;
 398     for (pe = first_polling_entry; pe != NULL; pe = pe->next) {
 399         ret |= pe->func(pe->opaque);
 400     }
 401     if (ret == 0) {
 402         int err;
 403         WaitObjects *w = &wait_objects;
 404
 405         qemu_mutex_unlock_iothread();
 406         ret = WaitForMultipleObjects(w->num, w->events, FALSE, *timeout);
 407         qemu_mutex_lock_iothread();
 408         if (WAIT_OBJECT_0 + 0 <= ret && ret <= WAIT_OBJECT_0 + w->num - 1) {
 409             if (w->func[ret - WAIT_OBJECT_0]) {
 410                 w->func[ret - WAIT_OBJECT_0](w->opaque[ret - WAIT_OBJECT_0]);
 411             }
 412
 413             /* Check for additional signaled events */
 414             for (i = (ret - WAIT_OBJECT_0 + 1); i < w->num; i++) {
 415                 /* Check if event is signaled */
 416                 ret2 = WaitForSingleObject(w->events[i], 0);
 417                 if (ret2 == WAIT_OBJECT_0) {
 418                     if (w->func[i]) {
 419                         w->func[i](w->opaque[i]);
 420                     }
 421                 } else if (ret2 != WAIT_TIMEOUT) {
 422                     err = GetLastError();
 423                     fprintf(stderr, "WaitForSingleObject error %d %d\n", i, err);
 424                 }
 425             }
 426         } else if (ret != WAIT_TIMEOUT) {
 427             err = GetLastError();
 428             fprintf(stderr, "WaitForMultipleObjects error %d %d\n", ret, err);
 429         }
 430     }
 431
 432     *timeout = 0;
 433 }
 434 #else
 435 static inline void os_host_main_loop_wait(int *timeout)
 436 {
 437 }
 438 #endif
 439
 440 int main_loop_wait(int nonblocking)
 441 {
 442     fd_set rfds, wfds, xfds;
 443     int ret, nfds;
 444     struct timeval tv;
 445     int timeout;
 446
 447     if (nonblocking) {
 448         timeout = 0;
 449     } else {
 450         timeout = qemu_calculate_timeout();
 451         qemu_bh_update_timeout(&timeout);
 452     }
 453
 454     os_host_main_loop_wait(&timeout);
 455
 456     tv.tv_sec = timeout / 1000;
 457     tv.tv_usec = (timeout % 1000) * 1000;
 458
 459     /* poll any events */
 460     /* XXX: separate device handlers from system ones */
 461     nfds = -1;
 462     FD_ZERO(&rfds);
 463     FD_ZERO(&wfds);
 464     FD_ZERO(&xfds);
 465
 466 #ifdef CONFIG_SLIRP
 467     slirp_select_fill(&nfds, &rfds, &wfds, &xfds);
 468 #endif
 469     qemu_iohandler_fill(&nfds, &rfds, &wfds, &xfds);
 470     glib_select_fill(&nfds, &rfds, &wfds, &xfds, &tv);
 471
 472     if (timeout > 0) {
 473         qemu_mutex_unlock_iothread();
 474     }
 475
 476     ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);
 477
 478     if (timeout > 0) {
 479         qemu_mutex_lock_iothread();
 480     }
 481
 482     glib_select_poll(&rfds, &wfds, &xfds, (ret < 0));
 483     qemu_iohandler_poll(&rfds, &wfds, &xfds, ret);
 484 #ifdef CONFIG_SLIRP
 485     slirp_select_poll(&rfds, &wfds, &xfds, (ret < 0));
 486 #endif
 487
 488     qemu_run_all_timers();
 489
 490     /* Check bottom-halves last in case any of the earlier events triggered
 491        them.  */
 492     qemu_bh_poll();
 493
 494     return ret;
 495 }