diff options
Diffstat (limited to 'event_notifier-posix.c')
-rw-r--r-- | event_notifier-posix.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/event_notifier-posix.c b/event_notifier-posix.c new file mode 100644 index 0000000000..6f3239a3fc --- /dev/null +++ b/event_notifier-posix.c @@ -0,0 +1,120 @@ +/* + * 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->rfd = fd; + e->wfd = fd; +} + +int event_notifier_init(EventNotifier *e, int active) +{ + int fds[2]; + int ret; + +#ifdef CONFIG_EVENTFD + ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC); +#else + ret = -1; + errno = ENOSYS; +#endif + if (ret >= 0) { + e->rfd = e->wfd = ret; + } else { + if (errno != ENOSYS) { + return -errno; + } + if (qemu_pipe(fds) < 0) { + return -errno; + } + ret = fcntl_setfl(fds[0], O_NONBLOCK); + if (ret < 0) { + ret = -errno; + goto fail; + } + ret = fcntl_setfl(fds[1], O_NONBLOCK); + if (ret < 0) { + ret = -errno; + goto fail; + } + e->rfd = fds[0]; + e->wfd = fds[1]; + } + if (active) { + event_notifier_set(e); + } + return 0; + +fail: + close(fds[0]); + close(fds[1]); + return ret; +} + +void event_notifier_cleanup(EventNotifier *e) +{ + if (e->rfd != e->wfd) { + close(e->rfd); + } + close(e->wfd); +} + +int event_notifier_get_fd(EventNotifier *e) +{ + return e->rfd; +} + +int event_notifier_set_handler(EventNotifier *e, + EventNotifierHandler *handler) +{ + return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e); +} + +int event_notifier_set(EventNotifier *e) +{ + static const uint64_t value = 1; + ssize_t ret; + + do { + ret = write(e->wfd, &value, sizeof(value)); + } while (ret < 0 && errno == EINTR); + + /* EAGAIN is fine, a read must be pending. */ + if (ret < 0 && errno != EAGAIN) { + return -errno; + } + return 0; +} + +int event_notifier_test_and_clear(EventNotifier *e) +{ + int value; + ssize_t len; + char buffer[512]; + + /* Drain the notify pipe. For eventfd, only 8 bytes will be read. */ + value = 0; + do { + len = read(e->rfd, buffer, sizeof(buffer)); + value |= (len > 0); + } while ((len == -1 && errno == EINTR) || len == sizeof(buffer)); + + return value; +} |