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