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