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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#include "rust_globals.h"
#include "rust_rng.h"
#include "rust_util.h"
size_t
rng_seed_size() {
randctx rctx;
return sizeof(rctx.randrsl);
}
// Initialization helpers for ISAAC RNG
void
rng_gen_seed(rust_kernel* kernel, uint8_t* dest, size_t size) {
#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);
if (fd == -1)
kernel->fatal("error opening /dev/urandom: %s", strerror(errno));
size_t amount = 0;
do {
ssize_t ret = read(fd, dest+amount, size-amount);
if (ret < 0)
kernel->fatal("error reading /dev/urandom: %s", strerror(errno));
else if (ret == 0)
kernel->fatal("somehow hit eof reading from /dev/urandom");
amount += (size_t)ret;
} while (amount < size);
int ret = close(fd);
// FIXME #3697: Why does this fail sometimes?
if (ret != 0)
kernel->log(log_warn, "error closing /dev/urandom: %s",
strerror(errno));
#endif
}
static void
isaac_init(rust_kernel *kernel, randctx *rctx,
uint8_t* user_seed, size_t seed_len) {
memset(rctx, 0, sizeof(randctx));
char *env_seed = kernel->env->rust_seed;
if (user_seed != NULL) {
// ignore bytes after the required length
if (seed_len > sizeof(rctx->randrsl)) {
seed_len = sizeof(rctx->randrsl);
}
memcpy(&rctx->randrsl, user_seed, 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 {
rng_gen_seed(kernel,
(uint8_t*)&rctx->randrsl,
sizeof(rctx->randrsl));
}
randinit(rctx, 1);
}
void
rng_init(rust_kernel* kernel, rust_rng* rng,
uint8_t *user_seed, size_t seed_len) {
isaac_init(kernel, &rng->rctx, user_seed, seed_len);
rng->reseedable = !user_seed && !kernel->env->rust_seed;
}
static void
rng_maybe_reseed(rust_kernel* kernel, rust_rng* rng) {
// If this RNG has generated more than 32KB of random data and was not
// seeded by the user or RUST_SEED, then we should reseed now.
const size_t RESEED_THRESHOLD = 32 * 1024;
size_t bytes_generated = rng->rctx.randc * sizeof(ub4);
if (bytes_generated < RESEED_THRESHOLD || !rng->reseedable) {
return;
}
rng_gen_seed(kernel,
(uint8_t*)rng->rctx.randrsl,
sizeof(rng->rctx.randrsl));
randinit(&rng->rctx, 1);
}
uint32_t
rng_gen_u32(rust_kernel* kernel, rust_rng* rng) {
uint32_t x = isaac_rand(&rng->rctx);
rng_maybe_reseed(kernel, rng);
return x;
}
//
// Local Variables:
// mode: C++
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//
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