remove dependency on serialize.h and util.h for SecureString

[novacoin.git] / src / allocators.h

diff --git a/src/allocators.h b/src/allocators.h
new file mode 100644 (file)
index 0000000..85d9cfb
--- /dev/null
+++ b/src/allocators.h
@@ -0,0 +1,119 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2012 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file license.txt or http://www.opensource.org/licenses/mit-license.php.
+#ifndef BITCOIN_ALLOCATORS_H
+#define BITCOIN_ALLOCATORS_H
+
+#include <string>
+
+#ifdef WIN32
+#define _WIN32_WINNT 0x0501
+#define WIN32_LEAN_AND_MEAN 1
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif
+#include <windows.h>
+// This is used to attempt to keep keying material out of swap
+// Note that VirtualLock does not provide this as a guarantee on Windows,
+// but, in practice, memory that has been VirtualLock'd almost never gets written to
+// the pagefile except in rare circumstances where memory is extremely low.
+#define mlock(p, n) VirtualLock((p), (n));
+#define munlock(p, n) VirtualUnlock((p), (n));
+#else
+#include <sys/mman.h>
+#include <limits.h>
+/* This comes from limits.h if it's not defined there set a sane default */
+#ifndef PAGESIZE
+#include <unistd.h>
+#define PAGESIZE sysconf(_SC_PAGESIZE)
+#endif
+#define mlock(a,b) \
+  mlock(((void *)(((size_t)(a)) & (~((PAGESIZE)-1)))),\
+  (((((size_t)(a)) + (b) - 1) | ((PAGESIZE) - 1)) + 1) - (((size_t)(a)) & (~((PAGESIZE) - 1))))
+#define munlock(a,b) \
+  munlock(((void *)(((size_t)(a)) & (~((PAGESIZE)-1)))),\
+  (((((size_t)(a)) + (b) - 1) | ((PAGESIZE) - 1)) + 1) - (((size_t)(a)) & (~((PAGESIZE) - 1))))
+#endif
+
+//
+// Allocator that locks its contents from being paged
+// out of memory and clears its contents before deletion.
+//
+template<typename T>
+struct secure_allocator : public std::allocator<T>
+{
+    // MSVC8 default copy constructor is broken
+    typedef std::allocator<T> base;
+    typedef typename base::size_type size_type;
+    typedef typename base::difference_type  difference_type;
+    typedef typename base::pointer pointer;
+    typedef typename base::const_pointer const_pointer;
+    typedef typename base::reference reference;
+    typedef typename base::const_reference const_reference;
+    typedef typename base::value_type value_type;
+    secure_allocator() throw() {}
+    secure_allocator(const secure_allocator& a) throw() : base(a) {}
+    template <typename U>
+    secure_allocator(const secure_allocator<U>& a) throw() : base(a) {}
+    ~secure_allocator() throw() {}
+    template<typename _Other> struct rebind
+    { typedef secure_allocator<_Other> other; };
+
+    T* allocate(std::size_t n, const void *hint = 0)
+    {
+        T *p;
+        p = std::allocator<T>::allocate(n, hint);
+        if (p != NULL)
+            mlock(p, sizeof(T) * n);
+        return p;
+    }
+
+    void deallocate(T* p, std::size_t n)
+    {
+        if (p != NULL)
+        {
+            memset(p, 0, sizeof(T) * n);
+            munlock(p, sizeof(T) * n);
+        }
+        std::allocator<T>::deallocate(p, n);
+    }
+};
+
+
+//
+// Allocator that clears its contents before deletion.
+//
+template<typename T>
+struct zero_after_free_allocator : public std::allocator<T>
+{
+    // MSVC8 default copy constructor is broken
+    typedef std::allocator<T> base;
+    typedef typename base::size_type size_type;
+    typedef typename base::difference_type  difference_type;
+    typedef typename base::pointer pointer;
+    typedef typename base::const_pointer const_pointer;
+    typedef typename base::reference reference;
+    typedef typename base::const_reference const_reference;
+    typedef typename base::value_type value_type;
+    zero_after_free_allocator() throw() {}
+    zero_after_free_allocator(const zero_after_free_allocator& a) throw() : base(a) {}
+    template <typename U>
+    zero_after_free_allocator(const zero_after_free_allocator<U>& a) throw() : base(a) {}
+    ~zero_after_free_allocator() throw() {}
+    template<typename _Other> struct rebind
+    { typedef zero_after_free_allocator<_Other> other; };
+
+    void deallocate(T* p, std::size_t n)
+    {
+        if (p != NULL)
+            memset(p, 0, sizeof(T) * n);
+        std::allocator<T>::deallocate(p, n);
+    }
+};
+
+// This is exactly like std::string, but with a custom allocator.
+// (secure_allocator<> is defined in serialize.h)
+typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;
+
+#endif