diff --git a/event_notifier-posix.c b/event_notifier-posix.c index 2c207e1399..6f3239a3fc 100644 --- a/event_notifier-posix.c +++ b/event_notifier-posix.c @@ -20,48 +20,101 @@ void event_notifier_init_fd(EventNotifier *e, int fd) { - e->fd = fd; + e->rfd = fd; + e->wfd = fd; } int event_notifier_init(EventNotifier *e, int active) { + int fds[2]; + int ret; + #ifdef CONFIG_EVENTFD - int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC); - if (fd < 0) - return -errno; - e->fd = fd; - return 0; + ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC); #else - return -ENOSYS; + 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) { - close(e->fd); + if (e->rfd != e->wfd) { + close(e->rfd); + } + close(e->wfd); } int event_notifier_get_fd(EventNotifier *e) { - return e->fd; + return e->rfd; } int event_notifier_set_handler(EventNotifier *e, EventNotifierHandler *handler) { - return qemu_set_fd_handler(e->fd, (IOHandler *)handler, NULL, e); + return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e); } int event_notifier_set(EventNotifier *e) { - uint64_t value = 1; - int r = write(e->fd, &value, sizeof(value)); - return r == sizeof(value); + 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) { - uint64_t value; - int r = read(e->fd, &value, sizeof(value)); - return r == sizeof(value); + 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; } diff --git a/event_notifier.h b/event_notifier.h index b283a497ce..88b57af7ce 100644 --- a/event_notifier.h +++ b/event_notifier.h @@ -23,7 +23,8 @@ struct EventNotifier { #ifdef _WIN32 HANDLE event; #else - int fd; + int rfd; + int wfd; #endif };