backends/rng-builtin.c

   1 /*
   2  * QEMU Builtin Random Number Generator Backend
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  * See the COPYING file in the top-level directory.
   6  */
   7
   8 #include "qemu/osdep.h"
   9 #include "sysemu/rng.h"
  10 #include "qemu/main-loop.h"
  11 #include "qemu/guest-random.h"
  12 #include "qom/object.h"
  13 #include "sysemu/replay.h"
  14
  15 OBJECT_DECLARE_SIMPLE_TYPE(RngBuiltin, RNG_BUILTIN)
  16
  17 struct RngBuiltin {
  18     RngBackend parent;
  19     QEMUBH *bh;
  20 };
  21
  22 static void rng_builtin_receive_entropy_bh(void *opaque)
  23 {
  24     RngBuiltin *s = opaque;
  25
  26     while (!QSIMPLEQ_EMPTY(&s->parent.requests)) {
  27         RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
  28
  29         qemu_guest_getrandom_nofail(req->data, req->size);
  30
  31         req->receive_entropy(req->opaque, req->data, req->size);
  32
  33         rng_backend_finalize_request(&s->parent, req);
  34     }
  35 }
  36
  37 static void rng_builtin_request_entropy(RngBackend *b, RngRequest *req)
  38 {
  39     RngBuiltin *s = RNG_BUILTIN(b);
  40
  41     replay_bh_schedule_event(s->bh);
  42 }
  43
  44 static void rng_builtin_init(Object *obj)
  45 {
  46     RngBuiltin *s = RNG_BUILTIN(obj);
  47
  48     s->bh = qemu_bh_new(rng_builtin_receive_entropy_bh, s);
  49 }
  50
  51 static void rng_builtin_finalize(Object *obj)
  52 {
  53     RngBuiltin *s = RNG_BUILTIN(obj);
  54
  55     qemu_bh_delete(s->bh);
  56 }
  57
  58 static void rng_builtin_class_init(ObjectClass *klass, void *data)
  59 {
  60     RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
  61
  62     rbc->request_entropy = rng_builtin_request_entropy;
  63 }
  64
  65 static const TypeInfo rng_builtin_info = {
  66     .name = TYPE_RNG_BUILTIN,
  67     .parent = TYPE_RNG_BACKEND,
  68     .instance_size = sizeof(RngBuiltin),
  69     .instance_init = rng_builtin_init,
  70     .instance_finalize = rng_builtin_finalize,
  71     .class_init = rng_builtin_class_init,
  72 };
  73
  74 static void register_types(void)
  75 {
  76     type_register_static(&rng_builtin_info);
  77 }
  78
  79 type_init(register_types);