move isaac RNG utility functions to new rust_rng.cpp file

1 files changed, 81 insertions, 0 deletions

diff --git a/src/rt/rust_rng.cpp b/src/rt/rust_rng.cpp
new file mode 100644
index 00000000000..5f4522c4978
--- /dev/null
+++ b/src/rt/rust_rng.cpp
@@ -0,0 +1,81 @@
+// 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"
+
+// Initialization helpers for ISAAC RNG
+
+void
+isaac_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
+}
+
+void
+isaac_init(rust_kernel *kernel, randctx *rctx, rust_vec_box* 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->body.fill < sizeof(rctx->randrsl)
+            ? user_seed->body.fill : sizeof(rctx->randrsl);
+        memcpy(&rctx->randrsl, user_seed->body.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(kernel, (uint8_t*) &rctx->randrsl, sizeof(rctx->randrsl));
+    }
+
+    randinit(rctx, 1);
+}
+
+//
+// Local Variables:
+// mode: C++
+// fill-column: 78;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// End:
+//