main-loop: create main-loop.c

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 495 insertions, 0 deletions

diff --git a/main-loop.c b/main-loop.c
new file mode 100644
index 0000000000..bfecdb7769
--- /dev/null
+++ b/main-loop.c
@@ -0,0 +1,495 @@
+/*
+ * 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 "config-host.h"
+#include <unistd.h>
+#include <signal.h>
+#include <time.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <stdbool.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#else
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+#include <sys/select.h>
+#include <sys/stat.h>
+#include "compatfd.h"
+#endif
+
+#include <glib.h>
+
+#include "main-loop.h"
+#include "qemu-timer.h"
+#include "slirp/libslirp.h"
+
+#ifndef _WIN32
+
+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);
+    pthread_sigmask(SIG_BLOCK, &set, NULL);
+
+    sigemptyset(&set);
+    sigaddset(&set, SIGIO);
+    sigaddset(&set, SIGALRM);
+    sigaddset(&set, SIGBUS);
+    pthread_sigmask(SIG_BLOCK, &set, NULL);
+
+    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 */
+
+HANDLE qemu_event_handle;
+
+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 (!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 qemu_init_main_loop(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 GPollFD poll_fds[1024 * 2]; /* this is probably overkill */
+static int n_poll_fds;
+static int max_priority;
+
+static void glib_select_fill(int *max_fd, fd_set *rfds, fd_set *wfds,
+                             fd_set *xfds, struct timeval *tv)
+{
+    GMainContext *context = g_main_context_default();
+    int i;
+    int timeout = 0, cur_timeout;
+
+    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);
+        }
+    }
+
+    cur_timeout = (tv->tv_sec * 1000) + ((tv->tv_usec + 500) / 1000);
+    if (timeout >= 0 && timeout < cur_timeout) {
+        tv->tv_sec = timeout / 1000;
+        tv->tv_usec = (timeout % 1000) * 1000;
+    }
+}
+
+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);
+    }
+}
+
+#ifdef _WIN32
+/***********************************************************/
+/* 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;
+    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->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];
+        }
+    }
+    if (found) {
+        w->num--;
+    }
+}
+
+static void os_host_main_loop_wait(int *timeout)
+{
+    int ret, ret2, i;
+    PollingEntry *pe;
+
+    /* 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) {
+        int err;
+        WaitObjects *w = &wait_objects;
+
+        qemu_mutex_unlock_iothread();
+        ret = WaitForMultipleObjects(w->num, w->events, FALSE, *timeout);
+        qemu_mutex_lock_iothread();
+        if (WAIT_OBJECT_0 + 0 <= ret && ret <= WAIT_OBJECT_0 + w->num - 1) {
+            if (w->func[ret - WAIT_OBJECT_0]) {
+                w->func[ret - WAIT_OBJECT_0](w->opaque[ret - WAIT_OBJECT_0]);
+            }
+
+            /* Check for additional signaled events */
+            for (i = (ret - WAIT_OBJECT_0 + 1); i < w->num; i++) {
+                /* Check if event is signaled */
+                ret2 = WaitForSingleObject(w->events[i], 0);
+                if (ret2 == WAIT_OBJECT_0) {
+                    if (w->func[i]) {
+                        w->func[i](w->opaque[i]);
+                    }
+                } else if (ret2 != WAIT_TIMEOUT) {
+                    err = GetLastError();
+                    fprintf(stderr, "WaitForSingleObject error %d %d\n", i, err);
+                }
+            }
+        } else if (ret != WAIT_TIMEOUT) {
+            err = GetLastError();
+            fprintf(stderr, "WaitForMultipleObjects error %d %d\n", ret, err);
+        }
+    }
+
+    *timeout = 0;
+}
+#else
+static inline void os_host_main_loop_wait(int *timeout)
+{
+}
+#endif
+
+int main_loop_wait(int nonblocking)
+{
+    fd_set rfds, wfds, xfds;
+    int ret, nfds;
+    struct timeval tv;
+    int timeout;
+
+    if (nonblocking) {
+        timeout = 0;
+    } else {
+        timeout = qemu_calculate_timeout();
+        qemu_bh_update_timeout(&timeout);
+    }
+
+    os_host_main_loop_wait(&timeout);
+
+    tv.tv_sec = timeout / 1000;
+    tv.tv_usec = (timeout % 1000) * 1000;
+
+    /* 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);
+    glib_select_fill(&nfds, &rfds, &wfds, &xfds, &tv);
+
+    if (timeout > 0) {
+        qemu_mutex_unlock_iothread();
+    }
+
+    ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);
+
+    if (timeout > 0) {
+        qemu_mutex_lock_iothread();
+    }
+
+    glib_select_poll(&rfds, &wfds, &xfds, (ret < 0));
+    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;
+}