1 files changed, 149 insertions, 0 deletions
diff --git a/cryptography/hazmat/bindings/openssl/binding.py b/cryptography/hazmat/bindings/openssl/binding.py
new file mode 100644
index 00000000..8b5e3449
--- /dev/null
+++ b/cryptography/hazmat/bindings/openssl/binding.py
@@ -0,0 +1,149 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import, division, print_function
+
+import sys
+
+import cffi
+
+_OSX_PRE_INCLUDE = """
+#ifdef __APPLE__
+#include <AvailabilityMacros.h>
+#define __ORIG_DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER \
+    DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+#undef DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+#define DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+#endif
+"""
+
+_OSX_POST_INCLUDE = """
+#ifdef __APPLE__
+#undef DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+#define DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER \
+    __ORIG_DEPRECATED_IN_MAC_OS_X_VERSION_10_7_AND_LATER
+#endif
+"""
+
+
+class Binding(object):
+    """
+    OpenSSL API wrapper.
+
+    Modules listed in the ``_modules`` listed should have the following
+    attributes:
+
+    * ``INCLUDES``: A string containg C includes.
+    * ``TYPES``: A string containing C declarations for types.
+    * ``FUNCTIONS``: A string containing C declarations for functions.
+    * ``MACROS``: A string containing C declarations for any macros.
+    * ``CUSTOMIZATIONS``: A string containing arbitrary top-level C code, this
+        can be used to do things like test for a define and provide an
+        alternate implementation based on that.
+    * ``CONDITIONAL_NAMES``: A dict mapping strings of condition names from the
+        library to a list of names which will not be present without the
+        condition.
+    """
+    _module_prefix = "cryptography.hazmat.bindings.openssl."
+    _modules = [
+        "asn1",
+        "bignum",
+        "bio",
+        "conf",
+        "crypto",
+        "dh",
+        "dsa",
+        "engine",
+        "err",
+        "evp",
+        "hmac",
+        "nid",
+        "objects",
+        "opensslv",
+        "pem",
+        "pkcs7",
+        "pkcs12",
+        "rand",
+        "rsa",
+        "ssl",
+        "x509",
+        "x509name",
+        "x509v3",
+    ]
+
+    ffi = None
+    lib = None
+
+    def __init__(self):
+        self._ensure_ffi_initialized()
+
+    @classmethod
+    def _ensure_ffi_initialized(cls):
+        if cls.ffi is not None and cls.lib is not None:
+            return
+
+        ffi = cffi.FFI()
+        includes = []
+        functions = []
+        macros = []
+        customizations = []
+        for name in cls._modules:
+            module_name = cls._module_prefix + name
+            __import__(module_name)
+            module = sys.modules[module_name]
+
+            ffi.cdef(module.TYPES)
+
+            macros.append(module.MACROS)
+            functions.append(module.FUNCTIONS)
+            includes.append(module.INCLUDES)
+            customizations.append(module.CUSTOMIZATIONS)
+
+        # loop over the functions & macros after declaring all the types
+        # so we can set interdependent types in different files and still
+        # have them all defined before we parse the funcs & macros
+        for func in functions:
+            ffi.cdef(func)
+        for macro in macros:
+            ffi.cdef(macro)
+
+        # We include functions here so that if we got any of their definitions
+        # wrong, the underlying C compiler will explode. In C you are allowed
+        # to re-declare a function if it has the same signature. That is:
+        #   int foo(int);
+        #   int foo(int);
+        # is legal, but the following will fail to compile:
+        #   int foo(int);
+        #   int foo(short);
+
+        lib = ffi.verify(
+            source="\n".join(
+                [_OSX_PRE_INCLUDE] +
+                includes +
+                [_OSX_POST_INCLUDE] +
+                functions +
+                customizations
+            ),
+            libraries=["crypto", "ssl"],
+        )
+
+        for name in cls._modules:
+            module_name = cls._module_prefix + name
+            module = sys.modules[module_name]
+            for condition, names in module.CONDITIONAL_NAMES.items():
+                if not getattr(lib, condition):
+                    for name in names:
+                        delattr(lib, name)
+
+        cls.ffi = ffi
+        cls.lib = lib