aboutsummaryrefslogtreecommitdiff
path: root/event_notifier.c
diff options
context:
space:
mode:
authorAvi Kivity <avi@redhat.com>2011-09-27 17:26:23 +0300
committerAnthony Liguori <aliguori@us.ibm.com>2011-11-01 16:52:08 -0500
commit2284451019a796eb2a37d70544e19d686de7f8c0 (patch)
treefed9234c5c05fa324053d3f6df0d7c2ab0b81cd2 /event_notifier.c
parent443916d1d9f1094a43d28c6b8cc60e3e7e27eb36 (diff)
downloadqemu-2284451019a796eb2a37d70544e19d686de7f8c0.zip
qemu-2284451019a796eb2a37d70544e19d686de7f8c0.tar.gz
qemu-2284451019a796eb2a37d70544e19d686de7f8c0.tar.bz2
event_notifier: move to top-level directory
Has no business in hw/. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'event_notifier.c')
-rw-r--r--event_notifier.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/event_notifier.c b/event_notifier.c
new file mode 100644
index 0000000..2c73555
--- /dev/null
+++ b/event_notifier.c
@@ -0,0 +1,61 @@
+/*
+ * 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. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include "event_notifier.h"
+#ifdef CONFIG_EVENTFD
+#include <sys/eventfd.h>
+#endif
+
+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_test_and_clear(EventNotifier *e)
+{
+ uint64_t value;
+ int r = read(e->fd, &value, sizeof(value));
+ return r == sizeof(value);
+}
+
+int event_notifier_test(EventNotifier *e)
+{
+ uint64_t value;
+ int r = read(e->fd, &value, sizeof(value));
+ if (r == sizeof(value)) {
+ /* restore previous value. */
+ int s = write(e->fd, &value, sizeof(value));
+ /* never blocks because we use EFD_SEMAPHORE.
+ * If we didn't we'd get EAGAIN on overflow
+ * and we'd have to write code to ignore it. */
+ assert(s == sizeof(value));
+ }
+ return r == sizeof(value);
+}