Commit a9b7b2ad authored by Anthony Liguori's avatar Anthony Liguori

rng: add RndBackend abstract object class

This is the backend used by devices that need to request entropy.
Signed-off-by: 's avatarAnthony Liguori <aliguori@us.ibm.com>
parent 0e558843
......@@ -100,6 +100,8 @@ common-obj-y += vl.o
common-obj-$(CONFIG_SLIRP) += slirp/
common-obj-y += backends/
######################################################################
# libseccomp
ifeq ($(CONFIG_SECCOMP),y)
......
common-obj-y += rng.o
/*
* 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);
/*
* 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
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