| // Copyright 2017 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include"base/rand_util.h" |
| |
| #include<zircon/syscalls.h> |
| |
| #include<atomic> |
| |
| #include"base/containers/span.h" |
| #include"base/feature_list.h" |
| #include"third_party/boringssl/src/include/openssl/rand.h" |
| |
| namespace base{ |
| |
| namespace internal{ |
| |
| namespace{ |
| |
| // The BoringSSl helpers are duplicated in rand_util_posix.cc and |
| // rand_util_win.cc. |
| std::atomic<bool> g_use_boringssl; |
| |
| BASE_FEATURE(kUseBoringSSLForRandBytes, |
| "UseBoringSSLForRandBytes", |
| FEATURE_DISABLED_BY_DEFAULT); |
| |
| }// namespace |
| |
| voidConfigureBoringSSLBackedRandBytesFieldTrial(){ |
| g_use_boringssl.store(FeatureList::IsEnabled(kUseBoringSSLForRandBytes), |
| std::memory_order_relaxed); |
| } |
| |
| boolUseBoringSSLForRandBytes(){ |
| return g_use_boringssl.load(std::memory_order_relaxed); |
| } |
| |
| }// namespace internal |
| |
| voidRandBytes(span<uint8_t> output){ |
| if(internal::UseBoringSSLForRandBytes()){ |
| // BoringSSL's RAND_bytes always returns 1. Any error aborts the program. |
| (void)RAND_bytes(output.data(), output.size()); |
| return; |
| } |
| |
| zx_cprng_draw(output.data(), output.size()); |
| } |
| |
| namespace internal{ |
| |
| doubleRandDoubleAvoidAllocation(){ |
| uint64_t number; |
| zx_cprng_draw(&number,sizeof(number)); |
| // This transformation is explained in rand_util.cc. |
| return(number>>11)*0x1.0p-53; |
| } |
| |
| }// namespace internal |
| |
| }// namespace base |
