rng: add RndBackend abstract object class
This is the backend used by devices that need to request entropy.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/backends/rng.c b/backends/rng.c
new file mode 100644
index 0000000..06f2611
--- /dev/null
+++ b/backends/rng.c
@@ -0,0 +1,93 @@
+/*
+ * QEMU Random Number Generator Backend
+ *
+ * Copyright IBM, Corp. 2012
+ *
+ * Authors:
+ * Anthony Liguori <aliguori@us.ibm.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/rng.h"
+#include "qerror.h"
+
+void rng_backend_request_entropy(RngBackend *s, size_t size,
+ EntropyReceiveFunc *receive_entropy,
+ void *opaque)
+{
+ RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
+
+ if (k->request_entropy) {
+ k->request_entropy(s, size, receive_entropy, opaque);
+ }
+}
+
+void rng_backend_cancel_requests(RngBackend *s)
+{
+ RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
+
+ if (k->cancel_requests) {
+ k->cancel_requests(s);
+ }
+}
+
+static bool rng_backend_prop_get_opened(Object *obj, Error **errp)
+{
+ RngBackend *s = RNG_BACKEND(obj);
+
+ return s->opened;
+}
+
+void rng_backend_open(RngBackend *s, Error **errp)
+{
+ object_property_set_bool(OBJECT(s), true, "opened", errp);
+}
+
+static void rng_backend_prop_set_opened(Object *obj, bool value, Error **errp)
+{
+ RngBackend *s = RNG_BACKEND(obj);
+ RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
+
+ if (value == s->opened) {
+ return;
+ }
+
+ if (!value && s->opened) {
+ error_set(errp, QERR_PERMISSION_DENIED);
+ return;
+ }
+
+ if (k->opened) {
+ k->opened(s, errp);
+ }
+
+ if (!error_is_set(errp)) {
+ s->opened = value;
+ }
+}
+
+static void rng_backend_init(Object *obj)
+{
+ object_property_add_bool(obj, "opened",
+ rng_backend_prop_get_opened,
+ rng_backend_prop_set_opened,
+ NULL);
+}
+
+static TypeInfo rng_backend_info = {
+ .name = TYPE_RNG_BACKEND,
+ .parent = TYPE_OBJECT,
+ .instance_size = sizeof(RngBackend),
+ .instance_init = rng_backend_init,
+ .class_size = sizeof(RngBackendClass),
+ .abstract = true,
+};
+
+static void register_types(void)
+{
+ type_register_static(&rng_backend_info);
+}
+
+type_init(register_types);
