Function system_crypt_random

src/unique_path.cpp:210–278

#endif // defined(BOOST_FILESYSTEM_POSIX_API) && !defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)

void system_crypt_random(void* buf, std::size_t len, boost::system::error_code* ec)
{
#if defined(BOOST_FILESYSTEM_POSIX_API)

#if defined(BOOST_FILESYSTEM_HAS_GETRANDOM) || defined(BOOST_FILESYSTEM_HAS_GETRANDOM_SYSCALL)

    int err = filesystem::detail::atomic_load_relaxed(fill_random)(buf, len);
    if (BOOST_UNLIKELY(err != 0))
        emit_error(err, ec, "boost::filesystem::unique_path");

#elif defined(BOOST_FILESYSTEM_HAS_ARC4RANDOM)

    arc4random_buf(buf, len);

#else

    int err = fill_random_dev_random(buf, len);
    if (BOOST_UNLIKELY(err != 0))
        emit_error(err, ec, "boost::filesystem::unique_path");

#endif

#else // defined(BOOST_FILESYSTEM_POSIX_API)

#if defined(BOOST_FILESYSTEM_HAS_BCRYPT)

    boost::winapi::BCRYPT_ALG_HANDLE_ handle;
    boost::winapi::NTSTATUS_ status = boost::winapi::BCryptOpenAlgorithmProvider(&handle, boost::winapi::BCRYPT_RNG_ALGORITHM_, nullptr, 0);
    if (BOOST_UNLIKELY(status != 0))
    {
    fail:
        emit_error(translate_ntstatus(status), ec, "boost::filesystem::unique_path");
        return;
    }

    status = boost::winapi::BCryptGenRandom(handle, static_cast< boost::winapi::PUCHAR_ >(buf), static_cast< boost::winapi::ULONG_ >(len), 0);

    boost::winapi::BCryptCloseAlgorithmProvider(handle, 0);

    if (BOOST_UNLIKELY(status != 0))
        goto fail;

#else // defined(BOOST_FILESYSTEM_HAS_BCRYPT)

    boost::winapi::HCRYPTPROV_ handle;
    boost::winapi::DWORD_ err = 0u;
    if (BOOST_UNLIKELY(!boost::winapi::CryptAcquireContextW(&handle, nullptr, nullptr, boost::winapi::PROV_RSA_FULL_, boost::winapi::CRYPT_VERIFYCONTEXT_ | boost::winapi::CRYPT_SILENT_)))
    {
        err = boost::winapi::GetLastError();

    fail:
        emit_error(err, ec, "boost::filesystem::unique_path");
        return;
    }

    boost::winapi::BOOL_ gen_ok = boost::winapi::CryptGenRandom(handle, static_cast< boost::winapi::DWORD_ >(len), static_cast< boost::winapi::BYTE_* >(buf));

    if (BOOST_UNLIKELY(!gen_ok))