diff options
| -rw-r--r-- | src/random.cpp | 49 | ||||
| -rw-r--r-- | src/random.h | 28 |
2 files changed, 46 insertions, 31 deletions
diff --git a/src/random.cpp b/src/random.cpp index 3f2465b2ed..e4c23ceac6 100644 --- a/src/random.cpp +++ b/src/random.cpp @@ -55,7 +55,7 @@ std::abort(); } -static inline int64_t GetPerformanceCounter() +static inline int64_t GetPerformanceCounter() noexcept { // Read the hardware time stamp counter when available. // See https://en.wikipedia.org/wiki/Time_Stamp_Counter for more information. @@ -105,7 +105,7 @@ static void InitHardwareRand() {} static void ReportHardwareRand() {} #endif -static bool GetHardwareRand(unsigned char* ent32) { +static bool GetHardwareRand(unsigned char* ent32) noexcept { #if defined(__x86_64__) || defined(__amd64__) || defined(__i386__) if (rdrand_supported) { uint8_t ok; @@ -285,7 +285,7 @@ struct RNGState { bool m_strongly_seeded GUARDED_BY(m_mutex) = false; std::unique_ptr<Mutex[]> m_mutex_openssl; - RNGState() + RNGState() noexcept { InitHardwareRand(); @@ -313,7 +313,7 @@ struct RNGState { * * If this function has never been called with strong_seed = true, false is returned. */ - bool MixExtract(unsigned char* out, size_t num, CSHA512&& hasher, bool strong_seed) + bool MixExtract(unsigned char* out, size_t num, CSHA512&& hasher, bool strong_seed) noexcept { assert(num <= 32); unsigned char buf[64]; @@ -344,7 +344,7 @@ struct RNGState { } }; -RNGState& GetRNGState() +RNGState& GetRNGState() noexcept { // This C++11 idiom relies on the guarantee that static variable are initialized // on first call, even when multiple parallel calls are permitted. @@ -364,13 +364,28 @@ void LockingCallbackOpenSSL(int mode, int i, const char* file, int line) NO_THRE } } -static void SeedTimestamp(CSHA512& hasher) +/* A note on the use of noexcept in the seeding functions below: + * + * None of the RNG code should ever throw any exception, with the sole exception + * of MilliSleep in SeedSleep, which can (and does) support interruptions which + * cause a boost::thread_interrupted to be thrown. + * + * This means that SeedSleep, and all functions that invoke it are throwing. + * However, we know that GetRandBytes() and GetStrongRandBytes() never trigger + * this sleeping logic, so they are noexcept. The same is true for all the + * GetRand*() functions that use GetRandBytes() indirectly. + * + * TODO: After moving away from interruptible boost-based thread management, + * everything can become noexcept here. + */ + +static void SeedTimestamp(CSHA512& hasher) noexcept { int64_t perfcounter = GetPerformanceCounter(); hasher.Write((const unsigned char*)&perfcounter, sizeof(perfcounter)); } -static void SeedFast(CSHA512& hasher) +static void SeedFast(CSHA512& hasher) noexcept { unsigned char buffer[32]; @@ -386,7 +401,7 @@ static void SeedFast(CSHA512& hasher) SeedTimestamp(hasher); } -static void SeedSlow(CSHA512& hasher) +static void SeedSlow(CSHA512& hasher) noexcept { unsigned char buffer[32]; @@ -426,7 +441,7 @@ static void SeedSleep(CSHA512& hasher) RandAddSeedPerfmon(hasher); } -static void SeedStartup(CSHA512& hasher) +static void SeedStartup(CSHA512& hasher) noexcept { #ifdef WIN32 RAND_screen(); @@ -482,11 +497,11 @@ static void ProcRand(unsigned char* out, int num, RNGLevel level) } } -void GetRandBytes(unsigned char* buf, int num) { ProcRand(buf, num, RNGLevel::FAST); } -void GetStrongRandBytes(unsigned char* buf, int num) { ProcRand(buf, num, RNGLevel::SLOW); } +void GetRandBytes(unsigned char* buf, int num) noexcept { ProcRand(buf, num, RNGLevel::FAST); } +void GetStrongRandBytes(unsigned char* buf, int num) noexcept { ProcRand(buf, num, RNGLevel::SLOW); } void RandAddSeedSleep() { ProcRand(nullptr, 0, RNGLevel::SLEEP); } -uint64_t GetRand(uint64_t nMax) +uint64_t GetRand(uint64_t nMax) noexcept { if (nMax == 0) return 0; @@ -501,12 +516,12 @@ uint64_t GetRand(uint64_t nMax) return (nRand % nMax); } -int GetRandInt(int nMax) +int GetRandInt(int nMax) noexcept { return GetRand(nMax); } -uint256 GetRandHash() +uint256 GetRandHash() noexcept { uint256 hash; GetRandBytes((unsigned char*)&hash, sizeof(hash)); @@ -520,7 +535,7 @@ void FastRandomContext::RandomSeed() requires_seed = false; } -uint256 FastRandomContext::rand256() +uint256 FastRandomContext::rand256() noexcept { if (bytebuf_size < 32) { FillByteBuffer(); @@ -541,7 +556,7 @@ std::vector<unsigned char> FastRandomContext::randbytes(size_t len) return ret; } -FastRandomContext::FastRandomContext(const uint256& seed) : requires_seed(false), bytebuf_size(0), bitbuf_size(0) +FastRandomContext::FastRandomContext(const uint256& seed) noexcept : requires_seed(false), bytebuf_size(0), bitbuf_size(0) { rng.SetKey(seed.begin(), 32); } @@ -592,7 +607,7 @@ bool Random_SanityCheck() return true; } -FastRandomContext::FastRandomContext(bool fDeterministic) : requires_seed(!fDeterministic), bytebuf_size(0), bitbuf_size(0) +FastRandomContext::FastRandomContext(bool fDeterministic) noexcept : requires_seed(!fDeterministic), bytebuf_size(0), bitbuf_size(0) { if (!fDeterministic) { return; diff --git a/src/random.h b/src/random.h index 592f36a406..038e3ecd78 100644 --- a/src/random.h +++ b/src/random.h @@ -21,10 +21,10 @@ * * Thread-safe. */ -void GetRandBytes(unsigned char* buf, int num); -uint64_t GetRand(uint64_t nMax); -int GetRandInt(int nMax); -uint256 GetRandHash(); +void GetRandBytes(unsigned char* buf, int num) noexcept; +uint64_t GetRand(uint64_t nMax) noexcept; +int GetRandInt(int nMax) noexcept; +uint256 GetRandHash() noexcept; /** * Gather entropy from various sources, feed it into the internal PRNG, and @@ -34,7 +34,7 @@ uint256 GetRandHash(); * * Thread-safe. */ -void GetStrongRandBytes(unsigned char* buf, int num); +void GetStrongRandBytes(unsigned char* buf, int num) noexcept; /** * Sleep for 1ms, gather entropy from various sources, and feed them to the PRNG state. @@ -78,10 +78,10 @@ private: } public: - explicit FastRandomContext(bool fDeterministic = false); + explicit FastRandomContext(bool fDeterministic = false) noexcept; /** Initialize with explicit seed (only for testing) */ - explicit FastRandomContext(const uint256& seed); + explicit FastRandomContext(const uint256& seed) noexcept; // Do not permit copying a FastRandomContext (move it, or create a new one to get reseeded). FastRandomContext(const FastRandomContext&) = delete; @@ -92,7 +92,7 @@ public: FastRandomContext& operator=(FastRandomContext&& from) noexcept; /** Generate a random 64-bit integer. */ - uint64_t rand64() + uint64_t rand64() noexcept { if (bytebuf_size < 8) FillByteBuffer(); uint64_t ret = ReadLE64(bytebuf + 64 - bytebuf_size); @@ -101,7 +101,7 @@ public: } /** Generate a random (bits)-bit integer. */ - uint64_t randbits(int bits) { + uint64_t randbits(int bits) noexcept { if (bits == 0) { return 0; } else if (bits > 32) { @@ -116,7 +116,7 @@ public: } /** Generate a random integer in the range [0..range). */ - uint64_t randrange(uint64_t range) + uint64_t randrange(uint64_t range) noexcept { --range; int bits = CountBits(range); @@ -130,19 +130,19 @@ public: std::vector<unsigned char> randbytes(size_t len); /** Generate a random 32-bit integer. */ - uint32_t rand32() { return randbits(32); } + uint32_t rand32() noexcept { return randbits(32); } /** generate a random uint256. */ - uint256 rand256(); + uint256 rand256() noexcept; /** Generate a random boolean. */ - bool randbool() { return randbits(1); } + bool randbool() noexcept { return randbits(1); } // Compatibility with the C++11 UniformRandomBitGenerator concept typedef uint64_t result_type; static constexpr uint64_t min() { return 0; } static constexpr uint64_t max() { return std::numeric_limits<uint64_t>::max(); } - inline uint64_t operator()() { return rand64(); } + inline uint64_t operator()() noexcept { return rand64(); } }; /** More efficient than using std::shuffle on a FastRandomContext. |