Merge pull request #5235

9eb5a5f build: pad header for osx libs (Cory Fields)
9ed8979 build: fix static dll link for mingw (Cory Fields)
19df238 build: shared lib build should work reasonably well now (Cory Fields)
269efa3 build: add quick consensus lib tests (Cory Fields)
cdd36c6 build: add --with-libs so that libs are optional (Cory Fields)
2cf5f16 build: add libbitcoinconsensus files and hook up the lib build (Cory Fields)
ee64c53 build: remove internal/protected build attribute checks (Cory Fields)
f36a40f build: check visibility attributes (Cory Fields)
811a765 build: mingw needs libssp for hardening with dlls (Cory Fields)
e0077de build: make a distinction between static app ldflags and static lib ldflags (Cory Fields)

10 files changed, 474 insertions, 16 deletions

diff --git a/.gitignore b/.gitignore
index c97432df92..7343e722d5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,6 +45,7 @@ src/qt/test/moc*.cpp
 
 .deps
 .dirstamp
+.libs
 .*.swp
 *.*~*
 *.bak
@@ -66,6 +67,10 @@ src/qt/test/moc*.cpp
 *.json.h
 *.raw.h
 
+#libtool object files
+*.lo
+*.la
+
 # Compilation and Qt preprocessor part
 *.qm
 Makefile
diff --git a/build-aux/m4/ax_gcc_func_attribute.m4 b/build-aux/m4/ax_gcc_func_attribute.m4
new file mode 100644
index 0000000000..275ca63a2c
--- /dev/null
+++ b/build-aux/m4/ax_gcc_func_attribute.m4
@@ -0,0 +1,217 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE)
+#
+# DESCRIPTION
+#
+#   This macro checks if the compiler supports one of GCC's function
+#   attributes; many other compilers also provide function attributes with
+#   the same syntax. Compiler warnings are used to detect supported
+#   attributes as unsupported ones are ignored by default so quieting
+#   warnings when using this macro will yield false positives.
+#
+#   The ATTRIBUTE parameter holds the name of the attribute to be checked.
+#
+#   If ATTRIBUTE is supported define HAVE_FUNC_ATTRIBUTE_<ATTRIBUTE>.
+#
+#   The macro caches its result in the ax_cv_have_func_attribute_<attribute>
+#   variable.
+#
+#   The macro currently supports the following function attributes:
+#
+#    alias
+#    aligned
+#    alloc_size
+#    always_inline
+#    artificial
+#    cold
+#    const
+#    constructor
+#    deprecated
+#    destructor
+#    dllexport
+#    dllimport
+#    error
+#    externally_visible
+#    flatten
+#    format
+#    format_arg
+#    gnu_inline
+#    hot
+#    ifunc
+#    leaf
+#    malloc
+#    noclone
+#    noinline
+#    nonnull
+#    noreturn
+#    nothrow
+#    optimize
+#    pure
+#    unused
+#    used
+#    visibility
+#    warning
+#    warn_unused_result
+#    weak
+#    weakref
+#
+#   Unsuppored function attributes will be tested with a prototype returning
+#   an int and not accepting any arguments and the result of the check might
+#   be wrong or meaningless so use with care.
+#
+# LICENSE
+#
+#   Copyright (c) 2013 Gabriele Svelto <gabriele.svelto@gmail.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.  This file is offered as-is, without any
+#   warranty.
+
+#serial 2
+
+AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [
+    AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1])
+
+    AC_CACHE_CHECK([for __attribute__(($1))], [ac_var], [
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([
+            m4_case([$1],
+                [alias], [
+                    int foo( void ) { return 0; }
+                    int bar( void ) __attribute__(($1("foo")));
+                ],
+                [aligned], [
+                    int foo( void ) __attribute__(($1(32)));
+                ],
+                [alloc_size], [
+                    void *foo(int a) __attribute__(($1(1)));
+                ],
+                [always_inline], [
+                    inline __attribute__(($1)) int foo( void ) { return 0; }
+                ],
+                [artificial], [
+                    inline __attribute__(($1)) int foo( void ) { return 0; }
+                ],
+                [cold], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [const], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [constructor], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [deprecated], [
+                    int foo( void ) __attribute__(($1("")));
+                ],
+                [destructor], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [dllexport], [
+                    __attribute__(($1)) int foo( void ) { return 0; }
+                ],
+                [dllimport], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [error], [
+                    int foo( void ) __attribute__(($1("")));
+                ],
+                [externally_visible], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [flatten], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [format], [
+                    int foo(const char *p, ...) __attribute__(($1(printf, 1, 2)));
+                ],
+                [format_arg], [
+                    char *foo(const char *p) __attribute__(($1(1)));
+                ],
+                [gnu_inline], [
+                    inline __attribute__(($1)) int foo( void ) { return 0; }
+                ],
+                [hot], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [ifunc], [
+                    int my_foo( void ) { return 0; }
+                    static int (*resolve_foo(void))(void) { return my_foo; }
+                    int foo( void ) __attribute__(($1("resolve_foo")));
+                ],
+                [leaf], [
+                    __attribute__(($1)) int foo( void ) { return 0; }
+                ],
+                [malloc], [
+                    void *foo( void ) __attribute__(($1));
+                ],
+                [noclone], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [noinline], [
+                    __attribute__(($1)) int foo( void ) { return 0; }
+                ],
+                [nonnull], [
+                    int foo(char *p) __attribute__(($1(1)));
+                ],
+                [noreturn], [
+                    void foo( void ) __attribute__(($1));
+                ],
+                [nothrow], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [optimize], [
+                    __attribute__(($1(3))) int foo( void ) { return 0; }
+                ],
+                [pure], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [unused], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [used], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [visibility], [
+                    int foo_def( void ) __attribute__(($1("default")));
+                    int foo_hid( void ) __attribute__(($1("hidden")));
+                ],
+                [warning], [
+                    int foo( void ) __attribute__(($1("")));
+                ],
+                [warn_unused_result], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [weak], [
+                    int foo( void ) __attribute__(($1));
+                ],
+                [weakref], [
+                    static int foo( void ) { return 0; }
+                    static int bar( void ) __attribute__(($1("foo")));
+                ],
+                [
+                 m4_warn([syntax], [Unsupported attribute $1, the test may fail])
+                 int foo( void ) __attribute__(($1));
+                ]
+            )], [])
+            ],
+            dnl GCC doesn't exit with an error if an unknown attribute is
+            dnl provided but only outputs a warning, so accept the attribute
+            dnl only if no warning were issued.
+            [AS_IF([test -s conftest.err],
+                [AS_VAR_SET([ac_var], [no])],
+                [AS_VAR_SET([ac_var], [yes])])],
+            [AS_VAR_SET([ac_var], [no])])
+    ])
+
+    AS_IF([test yes = AS_VAR_GET([ac_var])],
+        [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_FUNC_ATTRIBUTE_$1), 1,
+            [Define to 1 if the system has the `$1' function attribute])], [])
+
+    AS_VAR_POPDEF([ac_var])
+])
diff --git a/configure.ac b/configure.ac
index c0489f5be7..6784521d81 100644
--- a/configure.ac
+++ b/configure.ac
@@ -49,7 +49,7 @@ case $host in
   ;;
 esac
 dnl Libtool init checks.
-LT_INIT([disable-shared])
+LT_INIT([pic-only])
 
 dnl Check/return PATH for base programs.
 AC_PATH_TOOL(AR, ar)
@@ -201,12 +201,9 @@ case $host in
      AC_CHECK_LIB([iphlpapi],      [main],, AC_MSG_ERROR(lib missing))
      AC_CHECK_LIB([crypt32],      [main],, AC_MSG_ERROR(lib missing))
 
-     AX_CHECK_LINK_FLAG([[-static-libgcc]],[LDFLAGS="$LDFLAGS -static-libgcc"])
-     AX_CHECK_LINK_FLAG([[-static-libstdc++]],[LDFLAGS="$LDFLAGS -static-libstdc++"])
-
      # -static is interpreted by libtool, where it has a different meaning.
      # In libtool-speak, it's -all-static.
-     AX_CHECK_LINK_FLAG([[-static]],[LDFLAGS="$LDFLAGS -static"; LIBTOOL_LDFLAGS="$LIBTOOL_LDFLAGS -all-static"])
+     AX_CHECK_LINK_FLAG([[-static]],[LIBTOOL_APP_LDFLAGS="$LIBTOOL_APP_LDFLAGS -all-static"])
 
      AC_PATH_PROG([MAKENSIS], [makensis], none)
      if test x$MAKENSIS = xnone; then
@@ -229,6 +226,15 @@ case $host in
        *) AC_MSG_ERROR("Could not determine win32/win64 for installer") ;;
      esac
      AC_SUBST(WINDOWS_BITS)
+
+     dnl libtool insists upon adding -nostdlib and a list of objects/libs to link against.
+     dnl That breaks our ability to build dll's with static libgcc/libstdc++/libssp. Override
+     dnl its command here, with the predeps/postdeps removed, and -static inserted. Postdeps are
+     dnl also overridden to prevent their insertion later.
+     dnl This should only affect dll's.
+     archive_cmds_CXX="\$CC -shared \$libobjs \$deplibs \$compiler_flags -static -o \$output_objdir/\$soname \${wl}--enable-auto-image-base -Xlinker --out-implib -Xlinker \$lib"
+     postdeps_CXX=
+
      ;;
   *darwin*)
      TARGET_OS=darwin
@@ -279,6 +285,7 @@ case $host in
        esac
      fi
 
+     AX_CHECK_LINK_FLAG([[-Wl,-headerpad_max_install_names]], [LDFLAGS="$LDFLAGS -Wl,-headerpad_max_install_names"])
      CPPFLAGS="$CPPFLAGS -DMAC_OSX"
      ;;
    *linux*)
@@ -349,6 +356,10 @@ fi
 
 AX_CHECK_LINK_FLAG([[-Wl,--large-address-aware]], [LDFLAGS="$LDFLAGS -Wl,--large-address-aware"])
 
+AX_GCC_FUNC_ATTRIBUTE([visibility])
+AX_GCC_FUNC_ATTRIBUTE([dllexport])
+AX_GCC_FUNC_ATTRIBUTE([dllimport])
+
 if test x$use_glibc_compat != xno; then
 
   #__fdelt_chk's params and return type have changed from long unsigned int to long int.
@@ -389,6 +400,12 @@ if test x$use_hardening != xno; then
     AX_CHECK_LINK_FLAG([[-pie]], [HARDENED_LDFLAGS="$HARDENED_LDFLAGS -pie"])
   fi
 
+  case $host in
+    *mingw*)
+       AC_CHECK_LIB([ssp],      [main],, AC_MSG_ERROR(lib missing))
+    ;;
+  esac
+
   CXXFLAGS="$CXXFLAGS $HARDENED_CXXFLAGS"
   CPPFLAGS="$CPPFLAGS $HARDENED_CPPFLAGS"
   LDFLAGS="$LDFLAGS $HARDENED_LDFLAGS"
@@ -603,6 +620,12 @@ AC_ARG_WITH([utils],
   [build_bitcoin_utils=$withval],
   [build_bitcoin_utils=yes])
 
+AC_ARG_WITH([libs],
+  [AS_HELP_STRING([--with-libs],
+  [build libraries (default=yes)])],
+  [build_bitcoin_libs=$withval],
+  [build_bitcoin_libs=yes])
+
 AC_ARG_WITH([daemon],
   [AS_HELP_STRING([--with-daemon],
   [build bitcoind daemon (default=yes)])],
@@ -653,6 +676,13 @@ AC_MSG_CHECKING([whether to build utils (bitcoin-cli bitcoin-tx)])
 AM_CONDITIONAL([BUILD_BITCOIN_UTILS], [test x$build_bitcoin_utils = xyes])
 AC_MSG_RESULT($build_bitcoin_utils)
 
+AC_MSG_CHECKING([whether to build libraries])
+AM_CONDITIONAL([BUILD_BITCOIN_LIBS], [test x$build_bitcoin_libs = xyes])
+if test x$build_bitcoin_libs = xyes; then
+  AC_DEFINE(HAVE_CONSENSUS_LIB, 1, [Define this symbol if the consensus lib has been built])
+fi
+AC_MSG_RESULT($build_bitcoin_libs)
+
 dnl sets $bitcoin_enable_qt, $bitcoin_enable_qt_test, $bitcoin_enable_qt_dbus
 BITCOIN_QT_CONFIGURE([$use_pkgconfig], [qt4])
 
@@ -769,8 +799,8 @@ else
   AC_MSG_RESULT([no])
 fi
 
-if test x$build_bitcoin_utils$build_bitcoind$bitcoin_enable_qt$use_tests = xnononono; then
-  AC_MSG_ERROR([No targets! Please specify at least one of: --with-utils --with-daemon --with-gui or --enable-tests])
+if test x$build_bitcoin_utils$build_bitcoin_libs$build_bitcoind$bitcoin_enable_qt$use_tests = xnononono; then
+  AC_MSG_ERROR([No targets! Please specify at least one of: --with-utils --with-libs --with-daemon --with-gui or --enable-tests])
 fi
 
 AM_CONDITIONAL([TARGET_DARWIN], [test x$TARGET_OS = xdarwin])
@@ -801,7 +831,7 @@ AC_SUBST(CLIENT_VERSION_IS_RELEASE, _CLIENT_VERSION_IS_RELEASE)
 AC_SUBST(COPYRIGHT_YEAR, _COPYRIGHT_YEAR)
 
 AC_SUBST(RELDFLAGS)
-AC_SUBST(LIBTOOL_LDFLAGS)
+AC_SUBST(LIBTOOL_APP_LDFLAGS)
 AC_SUBST(USE_UPNP)
 AC_SUBST(USE_QRCODE)
 AC_SUBST(BOOST_LIBS)
diff --git a/src/Makefile.am b/src/Makefile.am
index 556fd49c0b..0d45203c90 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -49,6 +49,13 @@ BITCOIN_INCLUDES += $(BDB_CPPFLAGS)
 noinst_LIBRARIES += libbitcoin_wallet.a
 endif
 
+if BUILD_BITCOIN_LIBS
+lib_LTLIBRARIES = libbitcoinconsensus.la
+LIBBITCOIN_CONSENSUS=libbitcoinconsensus.la
+else
+LIBBITCOIN_CONSENSUS=
+endif
+
 bin_PROGRAMS =
 TESTS =
 
@@ -295,7 +302,7 @@ endif
 
 bitcoind_LDADD += $(BOOST_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS)
 bitcoind_CPPFLAGS = $(BITCOIN_INCLUDES)
-bitcoind_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS)
+bitcoind_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 
 # bitcoin-cli binary #
 bitcoin_cli_LDADD = \
@@ -324,12 +331,42 @@ bitcoin_tx_LDADD = \
 bitcoin_tx_SOURCES = bitcoin-tx.cpp
 bitcoin_tx_CPPFLAGS = $(BITCOIN_INCLUDES)
 #
-bitcoin_tx_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS)
+bitcoin_tx_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 
 if TARGET_WINDOWS
 bitcoin_cli_SOURCES += bitcoin-cli-res.rc
 endif
-bitcoin_cli_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS)
+bitcoin_cli_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+
+if BUILD_BITCOIN_LIBS
+include_HEADERS = script/bitcoinconsensus.h
+libbitcoinconsensus_la_SOURCES = \
+  core/transaction.cpp \
+  crypto/sha1.cpp \
+  crypto/sha2.cpp \
+  crypto/ripemd160.cpp \
+  eccryptoverify.cpp \
+  ecwrapper.cpp \
+  hash.cpp \
+  pubkey.cpp \
+  script/script.cpp \
+  script/interpreter.cpp \
+  script/bitcoinconsensus.cpp \
+  uint256.cpp \
+  utilstrencodings.cpp
+
+if GLIBC_BACK_COMPAT
+  libbitcoinconsensus_la_SOURCES += compat/glibc_compat.cpp
+  libbitcoinconsensus_la_SOURCES += compat/glibcxx_compat.cpp
+endif
+
+libbitcoinconsensus_la_LDFLAGS = -no-undefined $(RELDFLAGS)
+libbitcoinconsensus_la_LIBADD = $(CRYPTO_LIBS)
+libbitcoinconsensus_la_CPPFLAGS = $(CRYPTO_CFLAGS) -I$(builddir)/obj -DBUILD_BITCOIN_INTERNAL
+if USE_LIBSECP256K1
+libbitcoinconsensus_la_LIBADD += secp256k1/libsecp256k1.la
+endif
+endif
 
 CLEANFILES = leveldb/libleveldb.a leveldb/libmemenv.a *.gcda *.gcno
 
diff --git a/src/Makefile.qt.include b/src/Makefile.qt.include
index fac214bdca..898337ad6f 100644
--- a/src/Makefile.qt.include
+++ b/src/Makefile.qt.include
@@ -361,7 +361,7 @@ qt_bitcoin_qt_LDADD += $(LIBBITCOIN_WALLET)
 endif
 qt_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CRYPTO) $(LIBBITCOIN_UNIVALUE) $(LIBLEVELDB) $(LIBMEMENV) \
   $(BOOST_LIBS) $(QT_LIBS) $(QT_DBUS_LIBS) $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1)
-qt_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS)
+qt_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 qt_bitcoin_qt_LIBTOOLFLAGS = --tag CXX
 
 #locale/foo.ts -> locale/foo.qm
diff --git a/src/Makefile.qttest.include b/src/Makefile.qttest.include
index 622411ca68..c5392cf307 100644
--- a/src/Makefile.qttest.include
+++ b/src/Makefile.qttest.include
@@ -33,7 +33,7 @@ endif
 qt_test_test_bitcoin_qt_LDADD += $(LIBBITCOIN_CLI) $(LIBBITCOIN_COMMON) $(LIBBITCOIN_UTIL) $(LIBBITCOIN_CRYPTO) $(LIBBITCOIN_UNIVALUE) $(LIBLEVELDB) \
   $(LIBMEMENV) $(BOOST_LIBS) $(QT_DBUS_LIBS) $(QT_TEST_LIBS) $(QT_LIBS) \
   $(QR_LIBS) $(PROTOBUF_LIBS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS) $(LIBSECP256K1)
-qt_test_test_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS)
+qt_test_test_bitcoin_qt_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(QT_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 
 CLEAN_BITCOIN_QT_TEST = $(TEST_QT_MOC_CPP) qt/test/*.gcda qt/test/*.gcno
 
diff --git a/src/Makefile.test.include b/src/Makefile.test.include
index 79509c9a3e..5fd2afe50d 100644
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -85,8 +85,8 @@ if ENABLE_WALLET
 test_test_bitcoin_LDADD += $(LIBBITCOIN_WALLET)
 endif
 
-test_test_bitcoin_LDADD += $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS)
-test_test_bitcoin_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS)
+test_test_bitcoin_LDADD += $(LIBBITCOIN_CONSENSUS) $(BDB_LIBS) $(SSL_LIBS) $(CRYPTO_LIBS) $(MINIUPNPC_LIBS)
+test_test_bitcoin_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS) -static-libtool-libs
 
 nodist_test_test_bitcoin_SOURCES = $(GENERATED_TEST_FILES)
 
diff --git a/src/script/bitcoinconsensus.cpp b/src/script/bitcoinconsensus.cpp
new file mode 100644
index 0000000000..4faa760ad7
--- /dev/null
+++ b/src/script/bitcoinconsensus.cpp
@@ -0,0 +1,91 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "bitcoinconsensus.h"
+
+#include "core/transaction.h"
+#include "script/interpreter.h"
+#include "version.h"
+
+namespace {
+
+/** A class that deserializes a single CTransaction one time. */
+class TxInputStream
+{
+public:
+    TxInputStream(int nTypeIn, int nVersionIn, const unsigned char *txTo, size_t txToLen) :
+    m_type(nTypeIn),
+    m_version(nVersionIn),
+    m_data(txTo),
+    m_remaining(txToLen)
+    {}
+
+    TxInputStream& read(char* pch, size_t nSize)
+    {
+        if (nSize > m_remaining)
+            throw std::ios_base::failure(std::string(__func__) + ": end of data");
+
+        if (pch == NULL)
+            throw std::ios_base::failure(std::string(__func__) + ": bad destination buffer");
+
+        if (m_data == NULL)
+            throw std::ios_base::failure(std::string(__func__) + ": bad source buffer");
+
+        memcpy(pch, m_data, nSize);
+        m_remaining -= nSize;
+        m_data += nSize;
+        return *this;
+    }
+
+    template<typename T>
+    TxInputStream& operator>>(T& obj)
+    {
+        ::Unserialize(*this, obj, m_type, m_version);
+        return *this;
+    }
+
+private:
+    const int m_type;
+    const int m_version;
+    const unsigned char* m_data;
+    size_t m_remaining;
+};
+
+inline int set_error(bitcoinconsensus_error* ret, bitcoinconsensus_error serror)
+{
+    if (ret)
+        *ret = serror;
+    return 0;
+}
+
+} // anon namespace
+
+int bitcoinconsensus_verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
+                                    const unsigned char *txTo        , unsigned int txToLen,
+                                    unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err)
+{
+    try {
+        TxInputStream stream(SER_NETWORK, PROTOCOL_VERSION, txTo, txToLen);
+        CTransaction tx;
+        stream >> tx;
+        if (nIn >= tx.vin.size())
+            return set_error(err, bitcoinconsensus_ERR_TX_INDEX);
+        if (tx.GetSerializeSize(SER_NETWORK, PROTOCOL_VERSION) != txToLen)
+            return set_error(err, bitcoinconsensus_ERR_TX_SIZE_MISMATCH);
+
+         // Regardless of the verification result, the tx did not error.
+         set_error(err, bitcoinconsensus_ERR_OK);
+
+        return VerifyScript(tx.vin[nIn].scriptSig, CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen), flags, SignatureChecker(tx, nIn), NULL);
+    } catch (std::exception &e) {
+        return set_error(err, bitcoinconsensus_ERR_TX_DESERIALIZE); // Error deserializing
+    }
+}
+
+unsigned int bitcoinconsensus_version()
+{
+    // Just use the API version for now
+    return BITCOINCONSENSUS_API_VER;
+}
diff --git a/src/script/bitcoinconsensus.h b/src/script/bitcoinconsensus.h
new file mode 100644
index 0000000000..15e3337a8d
--- /dev/null
+++ b/src/script/bitcoinconsensus.h
@@ -0,0 +1,67 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_BITCOINCONSENSUS_H
+#define BITCOIN_BITCOINCONSENSUS_H
+
+#if defined(BUILD_BITCOIN_INTERNAL) && defined(HAVE_CONFIG_H)
+#include "config/bitcoin-config.h"
+  #if defined(_WIN32)
+    #if defined(DLL_EXPORT)
+      #if defined(HAVE_FUNC_ATTRIBUTE_DLLEXPORT)
+        #define EXPORT_SYMBOL __declspec(dllexport)
+      #else
+        #define EXPORT_SYMBOL
+      #endif
+    #endif
+  #elif defined(HAVE_FUNC_ATTRIBUTE_VISIBILITY)
+    #define EXPORT_SYMBOL __attribute__ ((visibility ("default")))
+  #endif
+#elif defined(MSC_VER) && !defined(STATIC_LIBBITCOINCONSENSUS)
+  #define EXPORT_SYMBOL __declspec(dllimport)
+#endif
+
+#ifndef EXPORT_SYMBOL
+  #define EXPORT_SYMBOL
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define BITCOINCONSENSUS_API_VER 0
+
+typedef enum bitcoinconsensus_error_t
+{
+    bitcoinconsensus_ERR_OK = 0,
+    bitcoinconsensus_ERR_TX_INDEX,
+    bitcoinconsensus_ERR_TX_SIZE_MISMATCH,
+    bitcoinconsensus_ERR_TX_DESERIALIZE,
+} bitcoinconsensus_error;
+
+/** Script verification flags */
+enum
+{
+    bitcoinconsensus_SCRIPT_FLAGS_VERIFY_NONE      = 0,
+    bitcoinconsensus_SCRIPT_FLAGS_VERIFY_P2SH      = (1U << 0), // evaluate P2SH (BIP16) subscripts
+};
+
+/// Returns 1 if the input nIn of the serialized transaction pointed to by
+/// txTo correctly spends the scriptPubKey pointed to by scriptPubKey under
+/// the additional constraints specified by flags.
+/// If not NULL, err will contain an error/success code for the operation
+EXPORT_SYMBOL int bitcoinconsensus_verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
+                                    const unsigned char *txTo        , unsigned int txToLen,
+                                    unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err);
+
+EXPORT_SYMBOL unsigned int bitcoinconsensus_version();
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#undef EXPORT_SYMBOL
+
+#endif // BITCOIN_BITCOINCONSENSUS_H
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index d98154571b..36aaa6903f 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -14,6 +14,10 @@
 #include "script/sign.h"
 #include "util.h"
 
+#if defined(HAVE_CONSENSUS_LIB)
+#include "script/bitcoinconsensus.h"
+#endif
+
 #include <fstream>
 #include <stdint.h>
 #include <string>
@@ -94,8 +98,15 @@ CMutableTransaction BuildSpendingTransaction(const CScript& scriptSig, const CMu
 void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, int flags, bool expect, const std::string& message)
 {
     ScriptError err;
-    BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, flags, SignatureChecker(BuildSpendingTransaction(scriptSig, BuildCreditingTransaction(scriptPubKey)), 0), &err) == expect, message);
+    CMutableTransaction tx = BuildSpendingTransaction(scriptSig, BuildCreditingTransaction(scriptPubKey));
+    CMutableTransaction tx2 = tx;
+    BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, flags, SignatureChecker(tx, 0), &err) == expect, message);
     BOOST_CHECK_MESSAGE(expect == (err == SCRIPT_ERR_OK), std::string(ScriptErrorString(err)) + ": " + message);
+#if defined(HAVE_CONSENSUS_LIB)
+    CDataStream stream(SER_NETWORK, PROTOCOL_VERSION);
+    stream << tx2;
+    BOOST_CHECK_MESSAGE(bitcoinconsensus_verify_script(begin_ptr(scriptPubKey), scriptPubKey.size(), (const unsigned char*)&stream[0], stream.size(), 0, flags, NULL) == expect,message);
+#endif
 }
 
 void static NegateSignatureS(std::vector<unsigned char>& vchSig) {