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add a seeded random number generator so that sequences of random numbers can be easily reproduced (for https://github.com/mozilla/rust/issues/2379)

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This commit is contained in:
Gareth Daniel Smith
2012-05-20 14:06:54 +01:00
committed by Brian Anderson
parent 64130f1589
commit c9f8ae02bc
5 changed files with 117 additions and 51 deletions
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87
src/rt/rust_util.h
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@@ -32,46 +32,6 @@ align_to(T size, size_t alignment) {
return x;
}
// Initialization helper for ISAAC RNG
inline void
isaac_init(rust_kernel *kernel, randctx *rctx)
{
memset(rctx, 0, sizeof(randctx));
char *rust_seed = kernel->env->rust_seed;
if (rust_seed != NULL) {
ub4 seed = (ub4) atoi(rust_seed);
for (size_t i = 0; i < RANDSIZ; i ++) {
memcpy(&rctx->randrsl[i], &seed, sizeof(ub4));
seed = (seed + 0x7ed55d16) + (seed << 12);
}
} else {
#ifdef __WIN32__
HCRYPTPROV hProv;
kernel->win32_require
(_T("CryptAcquireContext"),
CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT|CRYPT_SILENT));
kernel->win32_require
(_T("CryptGenRandom"),
CryptGenRandom(hProv, sizeof(rctx->randrsl),
(BYTE*)(&rctx->randrsl)));
kernel->win32_require
(_T("CryptReleaseContext"),
CryptReleaseContext(hProv, 0));
#else
int fd = open("/dev/urandom", O_RDONLY);
assert(fd > 0);
assert(read(fd, (void*) &rctx->randrsl, sizeof(rctx->randrsl))
== sizeof(rctx->randrsl));
assert(close(fd) == 0);
#endif
}
randinit(rctx, 1);
}
// Interior vectors (rust-user-code level).
struct
@@ -136,6 +96,53 @@ make_str_vec(rust_kernel* kernel, size_t nstrs, char **strs) {
return v;
}
// Initialization helpers for ISAAC RNG
inline void isaac_seed(uint8_t* dest)
{
size_t size = sizeof(ub4) * RANDSIZ;
#ifdef __WIN32__
HCRYPTPROV hProv;
kernel->win32_require
(_T("CryptAcquireContext"),
CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT|CRYPT_SILENT));
kernel->win32_require
(_T("CryptGenRandom"), CryptGenRandom(hProv, size, (BYTE*) dest));
kernel->win32_require
(_T("CryptReleaseContext"), CryptReleaseContext(hProv, 0));
#else
int fd = open("/dev/urandom", O_RDONLY);
assert(fd > 0);
assert(read(fd, dest, size) == (int) size);
assert(close(fd) == 0);
#endif
}
inline void
isaac_init(rust_kernel *kernel, randctx *rctx, rust_vec* user_seed)
{
memset(rctx, 0, sizeof(randctx));
char *env_seed = kernel->env->rust_seed;
if (user_seed != NULL) {
// ignore bytes after the required length
size_t seed_len = user_seed->fill < sizeof(rctx->randrsl)
? user_seed->fill : sizeof(rctx->randrsl);
memcpy(&rctx->randrsl, user_seed->data, seed_len);
} else if (env_seed != NULL) {
ub4 seed = (ub4) atoi(env_seed);
for (size_t i = 0; i < RANDSIZ; i ++) {
memcpy(&rctx->randrsl[i], &seed, sizeof(ub4));
seed = (seed + 0x7ed55d16) + (seed << 12);
}
} else {
isaac_seed((uint8_t*) &rctx->randrsl);
}
randinit(rctx, 1);
}
//
// Local Variables:
// mode: C++