event_notifier: add Win32 implementation

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

event_notifier-posix.c

@@ -0,0 +1,67 @@
+/*
+ * event notifier support
+ *
+ * Copyright Red Hat, Inc. 2010
+ *
+ * Authors:
+ *  Michael S. Tsirkin <mst@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu-common.h"
+#include "event_notifier.h"
+#include "qemu-char.h"
+
+#ifdef CONFIG_EVENTFD
+#include <sys/eventfd.h>
+#endif
+
+void event_notifier_init_fd(EventNotifier *e, int fd)
+{
+    e->fd = fd;
+}
+
+int event_notifier_init(EventNotifier *e, int active)
+{
+#ifdef CONFIG_EVENTFD
+    int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC);
+    if (fd < 0)
+        return -errno;
+    e->fd = fd;
+    return 0;
+#else
+    return -ENOSYS;
+#endif
+}
+
+void event_notifier_cleanup(EventNotifier *e)
+{
+    close(e->fd);
+}
+
+int event_notifier_get_fd(EventNotifier *e)
+{
+    return e->fd;
+}
+
+int event_notifier_set_handler(EventNotifier *e,
+                               EventNotifierHandler *handler)
+{
+    return qemu_set_fd_handler(e->fd, (IOHandler *)handler, NULL, e);
+}
+
+int event_notifier_set(EventNotifier *e)
+{
+    uint64_t value = 1;
+    int r = write(e->fd, &value, sizeof(value));
+    return r == sizeof(value);
+}
+
+int event_notifier_test_and_clear(EventNotifier *e)
+{
+    uint64_t value;
+    int r = read(e->fd, &value, sizeof(value));
+    return r == sizeof(value);
+}