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 "qemu/module.h"
  18 #include "qom/object_interfaces.h"
  19
  20 void rng_backend_request_entropy(RngBackend *s, size_t size,
  21                                  EntropyReceiveFunc *receive_entropy,
  22                                  void *opaque)
  23 {
  24     RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
  25     RngRequest *req;
  26
  27     if (k->request_entropy) {
  28         req = g_malloc(sizeof(*req));
  29
  30         req->offset = 0;
  31         req->size = size;
  32         req->receive_entropy = receive_entropy;
  33         req->opaque = opaque;
  34         req->data = g_malloc(req->size);
  35
  36         k->request_entropy(s, req);
  37
  38         QSIMPLEQ_INSERT_TAIL(&s->requests, req, next);
  39     }
  40 }
  41
  42 static bool rng_backend_prop_get_opened(Object *obj, Error **errp)
  43 {
  44     RngBackend *s = RNG_BACKEND(obj);
  45
  46     return s->opened;
  47 }
  48
  49 static void rng_backend_complete(UserCreatable *uc, Error **errp)
  50 {
  51     object_property_set_bool(OBJECT(uc), "opened", true, errp);
  52 }
  53
  54 static void rng_backend_prop_set_opened(Object *obj, bool value, Error **errp)
  55 {
  56     RngBackend *s = RNG_BACKEND(obj);
  57     RngBackendClass *k = RNG_BACKEND_GET_CLASS(s);
  58     Error *local_err = NULL;
  59
  60     if (value == s->opened) {
  61         return;
  62     }
  63
  64     if (!value && s->opened) {
  65         error_setg(errp, QERR_PERMISSION_DENIED);
  66         return;
  67     }
  68
  69     if (k->opened) {
  70         k->opened(s, &local_err);
  71         if (local_err) {
  72             error_propagate(errp, local_err);
  73             return;
  74         }
  75     }
  76
  77     s->opened = true;
  78 }
  79
  80 static void rng_backend_free_request(RngRequest *req)
  81 {
  82     g_free(req->data);
  83     g_free(req);
  84 }
  85
  86 static void rng_backend_free_requests(RngBackend *s)
  87 {
  88     RngRequest *req, *next;
  89
  90     QSIMPLEQ_FOREACH_SAFE(req, &s->requests, next, next) {
  91         rng_backend_free_request(req);
  92     }
  93
  94     QSIMPLEQ_INIT(&s->requests);
  95 }
  96
  97 void rng_backend_finalize_request(RngBackend *s, RngRequest *req)
  98 {
  99     QSIMPLEQ_REMOVE(&s->requests, req, RngRequest, next);
 100     rng_backend_free_request(req);
 101 }
 102
 103 static void rng_backend_init(Object *obj)
 104 {
 105     RngBackend *s = RNG_BACKEND(obj);
 106
 107     QSIMPLEQ_INIT(&s->requests);
 108
 109     object_property_add_bool(obj, "opened",
 110                              rng_backend_prop_get_opened,
 111                              rng_backend_prop_set_opened);
 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);