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author | Avi Kivity <avi@redhat.com> | 2011-09-27 17:26:23 +0300 |
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committer | Anthony Liguori <aliguori@us.ibm.com> | 2011-11-01 16:52:08 -0500 |
commit | 2284451019a796eb2a37d70544e19d686de7f8c0 (patch) | |
tree | fed9234c5c05fa324053d3f6df0d7c2ab0b81cd2 /event_notifier.c | |
parent | 443916d1d9f1094a43d28c6b8cc60e3e7e27eb36 (diff) | |
download | qemu-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.c | 61 |
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); +} |