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
  14 OBJECT_DECLARE_SIMPLE_TYPE(RngBuiltin, RNG_BUILTIN)
  15
  16 struct RngBuiltin {
  17     RngBackend parent;
  18     QEMUBH *bh;
  19 };
  20
  21 static void rng_builtin_receive_entropy_bh(void *opaque)
  22 {
  23     RngBuiltin *s = opaque;
  24
  25     while (!QSIMPLEQ_EMPTY(&s->parent.requests)) {
  26         RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
  27
  28         qemu_guest_getrandom_nofail(req->data, req->size);
  29
  30         req->receive_entropy(req->opaque, req->data, req->size);
  31
  32         rng_backend_finalize_request(&s->parent, req);
  33     }
  34 }
  35
  36 static void rng_builtin_request_entropy(RngBackend *b, RngRequest *req)
  37 {
  38     RngBuiltin *s = RNG_BUILTIN(b);
  39
  40     qemu_bh_schedule(s->bh);
  41 }
  42
  43 static void rng_builtin_init(Object *obj)
  44 {
  45     RngBuiltin *s = RNG_BUILTIN(obj);
  46
  47     s->bh = qemu_bh_new(rng_builtin_receive_entropy_bh, s);
  48 }
  49
  50 static void rng_builtin_finalize(Object *obj)
  51 {
  52     RngBuiltin *s = RNG_BUILTIN(obj);
  53
  54     qemu_bh_delete(s->bh);
  55 }
  56
  57 static void rng_builtin_class_init(ObjectClass *klass, void *data)
  58 {
  59     RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
  60
  61     rbc->request_entropy = rng_builtin_request_entropy;
  62 }
  63
  64 static const TypeInfo rng_builtin_info = {
  65     .name = TYPE_RNG_BUILTIN,
  66     .parent = TYPE_RNG_BACKEND,
  67     .instance_size = sizeof(RngBuiltin),
  68     .instance_init = rng_builtin_init,
  69     .instance_finalize = rng_builtin_finalize,
  70     .class_init = rng_builtin_class_init,
  71 };
  72
  73 static void register_types(void)
  74 {
  75     type_register_static(&rng_builtin_info);
  76 }
  77
  78 type_init(register_types);