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 typedef struct RngBuiltin RngBuiltin;
  15 DECLARE_INSTANCE_CHECKER(RngBuiltin, RNG_BUILTIN,
  16                          TYPE_RNG_BUILTIN)
  17
  18 struct RngBuiltin {
  19     RngBackend parent;
  20     QEMUBH *bh;
  21 };
  22
  23 static void rng_builtin_receive_entropy_bh(void *opaque)
  24 {
  25     RngBuiltin *s = opaque;
  26
  27     while (!QSIMPLEQ_EMPTY(&s->parent.requests)) {
  28         RngRequest *req = QSIMPLEQ_FIRST(&s->parent.requests);
  29
  30         qemu_guest_getrandom_nofail(req->data, req->size);
  31
  32         req->receive_entropy(req->opaque, req->data, req->size);
  33
  34         rng_backend_finalize_request(&s->parent, req);
  35     }
  36 }
  37
  38 static void rng_builtin_request_entropy(RngBackend *b, RngRequest *req)
  39 {
  40     RngBuiltin *s = RNG_BUILTIN(b);
  41
  42     qemu_bh_schedule(s->bh);
  43 }
  44
  45 static void rng_builtin_init(Object *obj)
  46 {
  47     RngBuiltin *s = RNG_BUILTIN(obj);
  48
  49     s->bh = qemu_bh_new(rng_builtin_receive_entropy_bh, s);
  50 }
  51
  52 static void rng_builtin_finalize(Object *obj)
  53 {
  54     RngBuiltin *s = RNG_BUILTIN(obj);
  55
  56     qemu_bh_delete(s->bh);
  57 }
  58
  59 static void rng_builtin_class_init(ObjectClass *klass, void *data)
  60 {
  61     RngBackendClass *rbc = RNG_BACKEND_CLASS(klass);
  62
  63     rbc->request_entropy = rng_builtin_request_entropy;
  64 }
  65
  66 static const TypeInfo rng_builtin_info = {
  67     .name = TYPE_RNG_BUILTIN,
  68     .parent = TYPE_RNG_BACKEND,
  69     .instance_size = sizeof(RngBuiltin),
  70     .instance_init = rng_builtin_init,
  71     .instance_finalize = rng_builtin_finalize,
  72     .class_init = rng_builtin_class_init,
  73 };
  74
  75 static void register_types(void)
  76 {
  77     type_register_static(&rng_builtin_info);
  78 }
  79
  80 type_init(register_types);