Annotation of qemu/main-loop.c, revision 1.1.1.1

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

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