From 2284451019a796eb2a37d70544e19d686de7f8c0 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 27 Sep 2011 17:26:23 +0300 Subject: event_notifier: move to top-level directory Has no business in hw/. Signed-off-by: Avi Kivity Signed-off-by: Anthony Liguori --- event_notifier.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 event_notifier.c (limited to 'event_notifier.c') diff --git a/event_notifier.c b/event_notifier.c new file mode 100644 index 0000000000..2c735556a1 --- /dev/null +++ b/event_notifier.c @@ -0,0 +1,61 @@ +/* + * event notifier support + * + * Copyright Red Hat, Inc. 2010 + * + * Authors: + * Michael S. Tsirkin + * + * 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 +#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); +} -- cgit v1.2.3