event_notifier: add event_notifier_set_handler

Win32 event notifiers are not file descriptors, so they will not be able
to use qemu_set_fd_handler.  But even if for now we only have a POSIX
version of EventNotifier, we can add a specific function that wraps
the call.

The wrapper passes the EventNotifier as the opaque value so that it will
be used with container_of.

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

event_notifier.c

@@ -12,6 +12,7 @@
 
 #include "qemu-common.h"
 #include "event_notifier.h"
+#include "qemu-char.h"
 
 #ifdef CONFIG_EVENTFD
 #include <sys/eventfd.h>
@@ -45,6 +46,12 @@ 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;

event_notifier.h

@@ -19,11 +19,14 @@ struct EventNotifier {
     int fd;
 };
 
+typedef void EventNotifierHandler(EventNotifier *);
+
 void event_notifier_init_fd(EventNotifier *, int fd);
 int event_notifier_init(EventNotifier *, int active);
 void event_notifier_cleanup(EventNotifier *);
 int event_notifier_get_fd(EventNotifier *);
 int event_notifier_set(EventNotifier *);
 int event_notifier_test_and_clear(EventNotifier *);
+int event_notifier_set_handler(EventNotifier *, EventNotifierHandler *);
 
 #endif