Archipelago » qemu

/*

 * QEMU System Emulator

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "qemu-common.h"

#include "qemu-timer.h"

#include "slirp/slirp.h"

#include "main-loop.h"

#ifndef _WIN32

#include "compatfd.h"

static int io_thread_fd = -1;

void qemu_notify_event(void)

{

    /* Write 8 bytes to be compatible with eventfd.  */

    static const uint64_t val = 1;

    ssize_t ret;

    if (io_thread_fd == -1) {

        return;

    }

    do {

        ret = write(io_thread_fd, &val, sizeof(val));

    } while (ret < 0 && errno == EINTR);

    /* EAGAIN is fine, a read must be pending.  */

    if (ret < 0 && errno != EAGAIN) {

        fprintf(stderr, "qemu_notify_event: write() failed: %s\n",

                strerror(errno));

        exit(1);

    }

}

static void qemu_event_read(void *opaque)

{

    int fd = (intptr_t)opaque;

    ssize_t len;

    char buffer[512];

    /* Drain the notify pipe.  For eventfd, only 8 bytes will be read.  */

    do {

        len = read(fd, buffer, sizeof(buffer));

    } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));

}

static int qemu_event_init(void)

{

    int err;

    int fds[2];

    err = qemu_eventfd(fds);

    if (err == -1) {

        return -errno;

    }

    err = fcntl_setfl(fds[0], O_NONBLOCK);

    if (err < 0) {

        goto fail;

    }

    err = fcntl_setfl(fds[1], O_NONBLOCK);

    if (err < 0) {

        goto fail;

    }

    qemu_set_fd_handler2(fds[0], NULL, qemu_event_read, NULL,

                         (void *)(intptr_t)fds[0]);

    io_thread_fd = fds[1];

    return 0;

fail:

    close(fds[0]);

    close(fds[1]);

    return err;

}

/* If we have signalfd, we mask out the signals we want to handle and then

 * use signalfd to listen for them.  We rely on whatever the current signal

 * handler is to dispatch the signals when we receive them.

 */

static void sigfd_handler(void *opaque)

{

    int fd = (intptr_t)opaque;

    struct qemu_signalfd_siginfo info;

    struct sigaction action;

    ssize_t len;

    while (1) {

        do {

            len = read(fd, &info, sizeof(info));

        } while (len == -1 && errno == EINTR);

        if (len == -1 && errno == EAGAIN) {

            break;

        }

        if (len != sizeof(info)) {

            printf("read from sigfd returned %zd: %m\n", len);

            return;

        }

        sigaction(info.ssi_signo, NULL, &action);

        if ((action.sa_flags & SA_SIGINFO) && action.sa_sigaction) {

            action.sa_sigaction(info.ssi_signo,

                                (siginfo_t *)&info, NULL);

        } else if (action.sa_handler) {

            action.sa_handler(info.ssi_signo);

        }

    }

}

static int qemu_signal_init(void)

{

    int sigfd;

    sigset_t set;

    /*

     * SIG_IPI must be blocked in the main thread and must not be caught

     * by sigwait() in the signal thread. Otherwise, the cpu thread will

     * not catch it reliably.

     */

    sigemptyset(&set);

    sigaddset(&set, SIG_IPI);

    sigaddset(&set, SIGIO);

    sigaddset(&set, SIGALRM);

    sigaddset(&set, SIGBUS);

    pthread_sigmask(SIG_BLOCK, &set, NULL);

    sigdelset(&set, SIG_IPI);

    sigfd = qemu_signalfd(&set);

    if (sigfd == -1) {

        fprintf(stderr, "failed to create signalfd\n");

        return -errno;

    }

    fcntl_setfl(sigfd, O_NONBLOCK);

    qemu_set_fd_handler2(sigfd, NULL, sigfd_handler, NULL,

                         (void *)(intptr_t)sigfd);

    return 0;

}

#else /* _WIN32 */

static HANDLE qemu_event_handle = NULL;

static void dummy_event_handler(void *opaque)

{

}

static int qemu_event_init(void)

{

    qemu_event_handle = CreateEvent(NULL, FALSE, FALSE, NULL);

    if (!qemu_event_handle) {

        fprintf(stderr, "Failed CreateEvent: %ld\n", GetLastError());

        return -1;

    }

    qemu_add_wait_object(qemu_event_handle, dummy_event_handler, NULL);

    return 0;

}

void qemu_notify_event(void)

{

    if (!qemu_event_handle) {

        return;

    }

    if (!SetEvent(qemu_event_handle)) {

        fprintf(stderr, "qemu_notify_event: SetEvent failed: %ld\n",

                GetLastError());

        exit(1);

    }

}

static int qemu_signal_init(void)

{

    return 0;

}

#endif

int main_loop_init(void)

{

    int ret;

    qemu_mutex_lock_iothread();

    ret = qemu_signal_init();

    if (ret) {

        return ret;

    }

    /* Note eventfd must be drained before signalfd handlers run */

    ret = qemu_event_init();

    if (ret) {

        return ret;

    }

    return 0;

}

static fd_set rfds, wfds, xfds;

static int nfds;

static GPollFD poll_fds[1024 * 2]; /* this is probably overkill */

static int n_poll_fds;

static int max_priority;

#ifndef _WIN32

static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds,

                             fd_set *xfds, int *cur_timeout)

{

    GMainContext *context = g_main_context_default();

    int i;

    int timeout = 0;

    g_main_context_prepare(context, &max_priority);

    n_poll_fds = g_main_context_query(context, max_priority, &timeout,

                                      poll_fds, ARRAY_SIZE(poll_fds));

    g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));

    for (i = 0; i < n_poll_fds; i++) {

        GPollFD *p = &poll_fds[i];

        if ((p->events & G_IO_IN)) {

            FD_SET(p->fd, rfds);

            *max_fd = MAX(*max_fd, p->fd);

        }

        if ((p->events & G_IO_OUT)) {

            FD_SET(p->fd, wfds);

            *max_fd = MAX(*max_fd, p->fd);

        }

        if ((p->events & G_IO_ERR)) {

            FD_SET(p->fd, xfds);

            *max_fd = MAX(*max_fd, p->fd);

        }

    }

    if (timeout >= 0 && timeout < *cur_timeout) {

        *cur_timeout = timeout;

    }

}

static void glib_select_poll(fd_set *rfds, fd_set *wfds, fd_set *xfds,

                             bool err)

{

    GMainContext *context = g_main_context_default();

    if (!err) {

        int i;

        for (i = 0; i < n_poll_fds; i++) {

            GPollFD *p = &poll_fds[i];

            if ((p->events & G_IO_IN) && FD_ISSET(p->fd, rfds)) {

                p->revents |= G_IO_IN;

            }

            if ((p->events & G_IO_OUT) && FD_ISSET(p->fd, wfds)) {

                p->revents |= G_IO_OUT;

            }

            if ((p->events & G_IO_ERR) && FD_ISSET(p->fd, xfds)) {

                p->revents |= G_IO_ERR;

            }

        }

    }

    if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {

        g_main_context_dispatch(context);

    }

}

static int os_host_main_loop_wait(int timeout)

{

    struct timeval tv;

    int ret;

    glib_select_fill(&nfds, &rfds, &wfds, &xfds, &timeout);

    if (timeout > 0) {

        qemu_mutex_unlock_iothread();

    }

    tv.tv_sec = timeout / 1000;

    tv.tv_usec = (timeout % 1000) * 1000;

    ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);

    if (timeout > 0) {

        qemu_mutex_lock_iothread();

    }

    glib_select_poll(&rfds, &wfds, &xfds, (ret < 0));

    return ret;

}

#else

/***********************************************************/

/* Polling handling */

typedef struct PollingEntry {

    PollingFunc *func;

    void *opaque;

    struct PollingEntry *next;

} PollingEntry;

static PollingEntry *first_polling_entry;

int qemu_add_polling_cb(PollingFunc *func, void *opaque)

{

    PollingEntry **ppe, *pe;

    pe = g_malloc0(sizeof(PollingEntry));

    pe->func = func;

    pe->opaque = opaque;

    for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next);

    *ppe = pe;

    return 0;

}

void qemu_del_polling_cb(PollingFunc *func, void *opaque)

{

    PollingEntry **ppe, *pe;

    for(ppe = &first_polling_entry; *ppe != NULL; ppe = &(*ppe)->next) {

        pe = *ppe;

        if (pe->func == func && pe->opaque == opaque) {

            *ppe = pe->next;

            g_free(pe);

            break;

        }

    }

}

/***********************************************************/

/* Wait objects support */

typedef struct WaitObjects {

    int num;

    int revents[MAXIMUM_WAIT_OBJECTS + 1];

    HANDLE events[MAXIMUM_WAIT_OBJECTS + 1];

    WaitObjectFunc *func[MAXIMUM_WAIT_OBJECTS + 1];

    void *opaque[MAXIMUM_WAIT_OBJECTS + 1];

} WaitObjects;

static WaitObjects wait_objects = {0};

int qemu_add_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)

{

    WaitObjects *w = &wait_objects;

    if (w->num >= MAXIMUM_WAIT_OBJECTS) {

        return -1;

    }

    w->events[w->num] = handle;

    w->func[w->num] = func;

    w->opaque[w->num] = opaque;

    w->revents[w->num] = 0;

    w->num++;

    return 0;

}

void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)

{

    int i, found;

    WaitObjects *w = &wait_objects;

    found = 0;

    for (i = 0; i < w->num; i++) {

        if (w->events[i] == handle) {

            found = 1;

        }

        if (found) {

            w->events[i] = w->events[i + 1];

            w->func[i] = w->func[i + 1];

            w->opaque[i] = w->opaque[i + 1];

            w->revents[i] = w->revents[i + 1];

        }

    }

    if (found) {

        w->num--;

    }

}

void qemu_fd_register(int fd)

{

    WSAEventSelect(fd, qemu_event_handle, FD_READ | FD_ACCEPT | FD_CLOSE |

                   FD_CONNECT | FD_WRITE | FD_OOB);

}

static int os_host_main_loop_wait(int timeout)

{

    GMainContext *context = g_main_context_default();

    int ret, i;

    PollingEntry *pe;

    WaitObjects *w = &wait_objects;

    static struct timeval tv0;

    /* XXX: need to suppress polling by better using win32 events */

    ret = 0;

    for (pe = first_polling_entry; pe != NULL; pe = pe->next) {

        ret |= pe->func(pe->opaque);

    }

    if (ret != 0) {

        return ret;

    }

    if (nfds >= 0) {

        ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);

        if (ret != 0) {

            timeout = 0;

        }

    }

    g_main_context_prepare(context, &max_priority);

    n_poll_fds = g_main_context_query(context, max_priority, &timeout,

                                      poll_fds, ARRAY_SIZE(poll_fds));

    g_assert(n_poll_fds <= ARRAY_SIZE(poll_fds));

    for (i = 0; i < w->num; i++) {

        poll_fds[n_poll_fds + i].fd = (DWORD_PTR)w->events[i];

        poll_fds[n_poll_fds + i].events = G_IO_IN;

    }

    qemu_mutex_unlock_iothread();

    ret = g_poll(poll_fds, n_poll_fds + w->num, timeout);

    qemu_mutex_lock_iothread();

    if (ret > 0) {

        for (i = 0; i < w->num; i++) {

            w->revents[i] = poll_fds[n_poll_fds + i].revents;

        }

        for (i = 0; i < w->num; i++) {

            if (w->revents[i] && w->func[i]) {

                w->func[i](w->opaque[i]);

            }

        }

    }

    if (g_main_context_check(context, max_priority, poll_fds, n_poll_fds)) {

        g_main_context_dispatch(context);

    }

    /* If an edge-triggered socket event occurred, select will return a

     * positive result on the next iteration.  We do not need to do anything

     * here.

     */

    return ret;

}

#endif

int main_loop_wait(int nonblocking)

{

    int ret, timeout;

    if (nonblocking) {

        timeout = 0;

    } else {

        timeout = qemu_calculate_timeout();

        qemu_bh_update_timeout(&timeout);

    }

    /* poll any events */

    /* XXX: separate device handlers from system ones */

    nfds = -1;

    FD_ZERO(&rfds);

    FD_ZERO(&wfds);

    FD_ZERO(&xfds);

#ifdef CONFIG_SLIRP

    slirp_select_fill(&nfds, &rfds, &wfds, &xfds);

#endif

    qemu_iohandler_fill(&nfds, &rfds, &wfds, &xfds);

    ret = os_host_main_loop_wait(timeout);

    qemu_iohandler_poll(&rfds, &wfds, &xfds, ret);

#ifdef CONFIG_SLIRP

    slirp_select_poll(&rfds, &wfds, &xfds, (ret < 0));

#endif

    qemu_run_all_timers();

    /* Check bottom-halves last in case any of the earlier events triggered

       them.  */

    qemu_bh_poll();

    return ret;

}