backends/rng.c

   1 /*
   2  * QEMU Random Number Generator Backend
   3  *
   4  * Copyright IBM, Corp. 2012
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "sysemu/rng.h"
  15 #include "qapi/qmp/qerror.h"
  16 #include "qom/object_interfaces.h"
  17
  18 void rng_backend_request_entropy(RngBackend *s, size_t size,
  19                                  EntropyReceiveFunc *receive_entropy,
  20                                  void *opaque)
  21 {
  22     RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
  23     RngRequest *req;
  24
  25     if (k->request_entropy) {
  26         req = g_malloc(sizeof(*req));
  27
  28         req->offset = 0;
  29         req->size = size;
  30         req->receive_entropy = receive_entropy;
  31         req->opaque = opaque;
  32         req->data = g_malloc(req->size);
  33
  34         k->request_entropy(s, req);
  35
  36         QSIMPLEQ_INSERT_TAIL(&s->requests, req, next);
  37     }
  38 }
  39
  40 static bool rng_backend_prop_get_opened(Object *obj, Error **errp)
  41 {
  42     RngBackend *s = RNG_BACKEND(obj);
  43
  44     return s->opened;
  45 }
  46
  47 static void rng_backend_complete(UserCreatable *uc, Error **errp)
  48 {
  49     object_property_set_bool(OBJECT(uc), true, "opened", errp);
  50 }
  51
  52 static void rng_backend_prop_set_opened(Object *obj, bool value, Error **errp)
  53 {
  54     RngBackend *s = RNG_BACKEND(obj);
  55     RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
  56     Error *local_err = NULL;
  57
  58     if (value == s->opened) {
  59         return;
  60     }
  61
  62     if (!value && s->opened) {
  63         error_setg(errp, QERR_PERMISSION_DENIED);
  64         return;
  65     }
  66
  67     if (k->opened) {
  68         k->opened(s, &local_err);
  69         if (local_err) {
  70             error_propagate(errp, local_err);
  71             return;
  72         }
  73     }
  74
  75     s->opened = true;
  76 }
  77
  78 static void rng_backend_free_request(RngRequest *req)
  79 {
  80     g_free(req->data);
  81     g_free(req);
  82 }
  83
  84 static void rng_backend_free_requests(RngBackend *s)
  85 {
  86     RngRequest *req, *next;
  87
  88     QSIMPLEQ_FOREACH_SAFE(req, &s->requests, next, next) {
  89         rng_backend_free_request(req);
  90     }
  91
  92     QSIMPLEQ_INIT(&s->requests);
  93 }
  94
  95 void rng_backend_finalize_request(RngBackend *s, RngRequest *req)
  96 {
  97     QSIMPLEQ_REMOVE(&s->requests, req, RngRequest, next);
  98     rng_backend_free_request(req);
  99 }
 100
 101 static void rng_backend_init(Object *obj)
 102 {
 103     RngBackend *s = RNG_BACKEND(obj);
 104
 105     QSIMPLEQ_INIT(&s->requests);
 106
 107     object_property_add_bool(obj, "opened",
 108                              rng_backend_prop_get_opened,
 109                              rng_backend_prop_set_opened,
 110                              NULL);
 111 }
 112
 113 static void rng_backend_finalize(Object *obj)
 114 {
 115     RngBackend *s = RNG_BACKEND(obj);
 116
 117     rng_backend_free_requests(s);
 118 }
 119
 120 static void rng_backend_class_init(ObjectClass *oc, void *data)
 121 {
 122     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 123
 124     ucc->complete = rng_backend_complete;
 125 }
 126
 127 static const TypeInfo rng_backend_info = {
 128     .name = TYPE_RNG_BACKEND,
 129     .parent = TYPE_OBJECT,
 130     .instance_size = sizeof(RngBackend),
 131     .instance_init = rng_backend_init,
 132     .instance_finalize = rng_backend_finalize,
 133     .class_size = sizeof(RngBackendClass),
 134     .class_init = rng_backend_class_init,
 135     .abstract = true,
 136     .interfaces = (InterfaceInfo[]) {
 137         { TYPE_USER_CREATABLE },
 138         { }
 139     }
 140 };
 141
 142 static void register_types(void)
 143 {
 144     type_register_static(&rng_backend_info);
 145 }
 146
 147 type_init(register_types);