Add implementation

1 files changed, 41 insertions, 0 deletions

diff --git a/openssl/utility.cxx b/openssl/utility.cxx
new file mode 100644
index 0000000..b9c974d
--- /dev/null
+++ b/openssl/utility.cxx
@@ -0,0 +1,41 @@
+// file      : openssl/utility.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2018 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <openssl/utility.hxx>
+
+#include <strings.h> // explicit_bzero()
+
+#include <cstdlib> // exit()
+#include <cstring> // memset()
+
+namespace openssl
+{
+  using namespace std;
+
+  void
+  mem_clear (void* p, size_t n)
+  {
+    // Note that explicit_bzero() is only available in glibc starting 2.25.
+    //
+#if defined (__GLIBC__)       && \
+    defined (__GLIBC_MINOR__) && \
+    (__GLIBC__ > 2 || __GLIBC__ == 2 && __GLIBC_MINOR__ >= 25)
+
+    explicit_bzero (p, n);
+
+#else
+
+    memset (p, 0, n);
+
+    // Make sure the function is not optimized out.
+    //
+    for (char *i (reinterpret_cast<char*> (p)), *e (i + n); i != e; ++i)
+    {
+      if (*i != '\0')
+        exit (*i);
+    }
+
+#endif
+  }
+}