first step of v2 final release

crypto/rand/rand_extra/forkunsafe.c

@@ -0,0 +1,44 @@
+/* Copyright (c) 2017, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#include <stdlib.h>
+
+#include "../fipsmodule/rand/internal.h"
+
+
+/* g_buffering_enabled is true if fork-unsafe buffering has been enabled. */
+static int g_buffering_enabled = 0;
+
+/* g_lock protects |g_buffering_enabled|. */
+static struct CRYPTO_STATIC_MUTEX g_lock = CRYPTO_STATIC_MUTEX_INIT;
+
+void RAND_enable_fork_unsafe_buffering(int fd) {
+  /* We no longer support setting the file-descriptor with this function. */
+  if (fd != -1) {
+    abort();
+  }
+
+  CRYPTO_STATIC_MUTEX_lock_write(&g_lock);
+  g_buffering_enabled = 1;
+  CRYPTO_STATIC_MUTEX_unlock_write(&g_lock);
+}
+
+int rand_fork_unsafe_buffering_enabled(void) {
+  CRYPTO_STATIC_MUTEX_lock_read(&g_lock);
+  const int ret = g_buffering_enabled;
+  CRYPTO_STATIC_MUTEX_unlock_read(&g_lock);
+  return ret;
+}