unsigned
random_device::operator()()
{
unsigned r;
size_t n = sizeof(r);
size_t bytes_written;
int error = nacl_secure_random(&r, n, &bytes_written);
if (error != 0)
__throw_system_error(error, "random_device failed getting bytes");
else if (bytes_written != n)
__throw_runtime_error("random_device failed to obtain enough bytes");
return r;
}
void GenRandomBytes(void* dest, size_t size)
{
#ifdef _WIN32
HCRYPTPROV prov;
if (!CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
Sys::Error("CryptAcquireContext failed: %s", Win32StrError(GetLastError()));
if (!CryptGenRandom(prov, size, (BYTE*)dest))
Sys::Error("CryptGenRandom failed: %s", Win32StrError(GetLastError()));
CryptReleaseContext(prov, 0);
#elif defined(__native_client__)
size_t bytes_written;
if (nacl_secure_random(dest, size, &bytes_written) != 0 || bytes_written != size)
Sys::Error("nacl_secure_random failed");
#else
int fd = open("/dev/urandom", O_RDONLY);
if (fd == -1)
Sys::Error("Failed to open /dev/urandom: %s", strerror(errno));
if (read(fd, dest, size) != (ssize_t) size)
Sys::Error("Failed to read from /dev/urandom: %s", strerror(errno));
close(fd);
#endif
}