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authorAnthony Liguori <aliguori@us.ibm.com>2012-06-25 10:03:47 -0500
committerAnthony Liguori <aliguori@us.ibm.com>2012-11-16 08:36:12 -0600
commita9b7b2ad7b075dba5495271706670e5c6b1304bc (patch)
treeafb6265b0527f4c88aae906c69e079d97303d052
parent0e5588438d921b8686bbf455f400f727b2ff7b62 (diff)
downloadqemu-arm-a9b7b2ad7b075dba5495271706670e5c6b1304bc.tar.gz
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>
-rw-r--r--Makefile.objs2
-rw-r--r--backends/Makefile.objs1
-rw-r--r--backends/rng.c93
-rw-r--r--include/qemu/rng.h93
4 files changed, 189 insertions, 0 deletions
diff --git a/Makefile.objs b/Makefile.objs
index 37be7e26f7..dc1e699914 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -100,6 +100,8 @@ common-obj-y += vl.o
common-obj-$(CONFIG_SLIRP) += slirp/
+common-obj-y += backends/
+
######################################################################
# libseccomp
ifeq ($(CONFIG_SECCOMP),y)
diff --git a/backends/Makefile.objs b/backends/Makefile.objs
new file mode 100644
index 0000000000..06e08c782d
--- /dev/null
+++ b/backends/Makefile.objs
@@ -0,0 +1 @@
+common-obj-y += rng.o
diff --git a/backends/rng.c b/backends/rng.c
new file mode 100644
index 0000000000..06f261180c
--- /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);
diff --git a/include/qemu/rng.h b/include/qemu/rng.h
new file mode 100644
index 0000000000..7e9d6723ff
--- /dev/null
+++ b/include/qemu/rng.h
@@ -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.
+ */
+
+#ifndef QEMU_RNG_H
+#define QEMU_RNG_H
+
+#include "qemu/object.h"
+#include "qemu-common.h"
+#include "error.h"
+
+#define TYPE_RNG_BACKEND "rng-backend"
+#define RNG_BACKEND(obj) \
+ OBJECT_CHECK(RngBackend, (obj), TYPE_RNG_BACKEND)
+#define RNG_BACKEND_GET_CLASS(obj) \
+ OBJECT_GET_CLASS(RngBackendClass, (obj), TYPE_RNG_BACKEND)
+#define RNG_BACKEND_CLASS(klass) \
+ OBJECT_CLASS_CHECK(RngBackendClass, (klass), TYPE_RNG_BACKEND)
+
+typedef struct RngBackendClass RngBackendClass;
+typedef struct RngBackend RngBackend;
+
+typedef void (EntropyReceiveFunc)(void *opaque,
+ const void *data,
+ size_t size);
+
+struct RngBackendClass
+{
+ ObjectClass parent_class;
+
+ void (*request_entropy)(RngBackend *s, size_t size,
+ EntropyReceiveFunc *recieve_entropy, void *opaque);
+ void (*cancel_requests)(RngBackend *s);
+
+ void (*opened)(RngBackend *s, Error **errp);
+};
+
+struct RngBackend
+{
+ Object parent;
+
+ /*< protected >*/
+ bool opened;
+};
+
+/**
+ * rng_backend_request_entropy:
+ * @s: the backend to request entropy from
+ * @size: the number of bytes of data to request
+ * @receive_entropy: a function to be invoked when entropy is available
+ * @opaque: data that should be passed to @receive_entropy
+ *
+ * This function is used by the front-end to request entropy from an entropy
+ * source. This function can be called multiple times before @receive_entropy
+ * is invoked with different values of @receive_entropy and @opaque. The
+ * backend will queue each request and handle appropriate.
+ *
+ * The backend does not need to pass the full amount of data to @receive_entropy
+ * but will pass at a value greater than 0.
+ */
+void rng_backend_request_entropy(RngBackend *s, size_t size,
+ EntropyReceiveFunc *receive_entropy,
+ void *opaque);
+
+/**
+ * rng_backend_cancel_requests:
+ * @s: the backend to cancel all pending requests in
+ *
+ * Cancels all pending requests submitted by @rng_backend_request_entropy. This
+ * should be used by a device during reset or in preparation for live migration
+ * to stop tracking any request.
+ */
+void rng_backend_cancel_requests(RngBackend *s);
+
+/**
+ * rng_backend_open:
+ * @s: the backend to open
+ * @errp: a pointer to return the #Error object if an error occurs.
+ *
+ * This function will open the backend if it is not already open. Calling this
+ * function on an already opened backend will not result in an error.
+ */
+void rng_backend_open(RngBackend *s, Error **errp);
+
+#endif