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Diffstat (limited to 'util/event_notifier-posix.c')
-rw-r--r--util/event_notifier-posix.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/util/event_notifier-posix.c b/util/event_notifier-posix.c
new file mode 100644
index 0000000000..713d7560d0
--- /dev/null
+++ b/util/event_notifier-posix.c
@@ -0,0 +1,121 @@
+/*
+ * 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 "qemu/event_notifier.h"
+#include "char/char.h"
+#include "qemu/main-loop.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;
+}