base/rand_util_nacl.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/rand_util.h"
   6 #include "base/rand_util_c.h"
   7
   8 #include "base/lazy_instance.h"
   9 #include "base/logging.h"
  10
  11 // TODO(bbudge) Replace this with a proper system header file when NaCl
  12 // provides one.
  13 #include "native_client/src/untrusted/irt/irt.h"
  14
  15 namespace {
  16
  17 // Create a wrapper class so we can cache the NaCl random number interface.
  18 class URandomInterface {
  19  public:
  20   URandomInterface() {
  21     size_t result = nacl_interface_query(NACL_IRT_RANDOM_v0_1,
  22                                          &interface_,
  23                                          sizeof(interface_));
  24     DCHECK_EQ(result, sizeof(interface_)) << "Can't get random interface.";
  25   }
  26
  27   uint64 get_random_bytes() const {
  28     size_t nbytes;
  29     uint64 result;
  30     int error = interface_.get_random_bytes(&result,
  31                                             sizeof(result),
  32                                             &nbytes);
  33     DCHECK_EQ(error, 0);
  34     DCHECK_EQ(nbytes, sizeof(result));
  35     return result;
  36   }
  37
  38  private:
  39   struct nacl_irt_random interface_;
  40 };
  41
  42 base::LazyInstance<URandomInterface> g_urandom_interface =
  43     LAZY_INSTANCE_INITIALIZER;
  44
  45 }  // namespace
  46
  47 namespace base {
  48
  49 uint64 RandUint64() {
  50   return g_urandom_interface.Pointer()->get_random_bytes();
  51 }
  52
  53 }  // namespace base
  54