1 files changed, 56 insertions, 0 deletions
diff --git a/src/crypto/rand/hwrand.c b/src/crypto/rand/hwrand.c
new file mode 100644
index 0000000..73d3de7
--- /dev/null
+++ b/src/crypto/rand/hwrand.c
@@ -0,0 +1,56 @@
+/* Copyright (c) 2015, 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 <string.h>
+
+#include <openssl/cpu.h>
+
+
+#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM)
+
+int CRYPTO_have_hwrand(void) {
+  return (OPENSSL_ia32cap_P[1] & (1u << 30)) != 0;
+}
+
+/* CRYPTO_rdrand is defined in asm/rdrand-x86_64.pl */
+extern uint64_t CRYPTO_rdrand(void);
+
+void CRYPTO_hwrand(uint8_t *buf, size_t len) {
+  while (len >= 8) {
+    uint64_t rand = CRYPTO_rdrand();
+    memcpy(buf, &rand, sizeof(rand));
+    len -= sizeof(rand);
+    buf += sizeof(rand);
+  }
+
+  if (len > 0) {
+    uint64_t rand = CRYPTO_rdrand();
+    memcpy(buf, &rand, len);
+  }
+}
+
+#else
+
+int CRYPTO_have_hwrand(void) {
+  return 0;
+}
+
+void CRYPTO_hwrand(uint8_t *buf, size_t len) {
+  abort();
+}
+
+#endif