Split up ffi.cpp into several files

It was getting pretty big and would get worse over time, eg whenver
I get around to adding TLS support.

1 files changed, 197 insertions, 0 deletions

diff --git a/src/lib/ffi/ffi_util.h b/src/lib/ffi/ffi_util.h
new file mode 100644
index 000000000..919efdd75
--- /dev/null
+++ b/src/lib/ffi/ffi_util.h
@@ -0,0 +1,197 @@
+/*
+* (C) 2015,2017 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_FFI_UTILS_H__
+#define BOTAN_FFI_UTILS_H__
+
+#include <cstdint>
+#include <memory>
+#include <stdexcept>
+#include <botan/exceptn.h>
+#include <botan/mem_ops.h>
+
+namespace Botan_FFI {
+
+#define BOTAN_ASSERT_ARG_NON_NULL(p) \
+   do { if(!p) throw Botan::Invalid_Argument("Argument " #p " is null"); } while(0)
+
+class FFI_Error : public Botan::Exception
+   {
+   public:
+      explicit FFI_Error(const std::string& what) : Exception("FFI error", what) {}
+   };
+
+template<typename T, uint32_t MAGIC>
+struct botan_struct
+   {
+   public:
+      botan_struct(T* obj) : m_magic(MAGIC), m_obj(obj) {}
+      ~botan_struct() { m_magic = 0; m_obj.reset(); }
+
+      bool magic_ok() const { return (m_magic == MAGIC); }
+
+      T* get() const
+         {
+         if(magic_ok() == false)
+            throw FFI_Error("Bad magic " + std::to_string(m_magic) +
+                            " in ffi object expected " + std::to_string(MAGIC));
+         return m_obj.get();
+         }
+   private:
+      uint32_t m_magic = 0;
+      std::unique_ptr<T> m_obj;
+   };
+
+#define BOTAN_FFI_DECLARE_STRUCT(NAME, TYPE, MAGIC) \
+   struct NAME : public botan_struct<TYPE, MAGIC> { explicit NAME(TYPE* x) : botan_struct(x) {} }
+
+// Declared in ffi.cpp
+int ffi_error_exception_thrown(const char* func_name, const char* exn);
+
+template<typename T, uint32_t M>
+T& safe_get(botan_struct<T,M>* p)
+   {
+   if(!p)
+      throw FFI_Error("Null pointer argument");
+   if(T* t = p->get())
+      return *t;
+   throw FFI_Error("Invalid object pointer");
+   }
+
+template<typename T, uint32_t M>
+const T& safe_get(const botan_struct<T,M>* p)
+   {
+   if(!p)
+      throw FFI_Error("Null pointer argument");
+   if(const T* t = p->get())
+      return *t;
+   throw FFI_Error("Invalid object pointer");
+   }
+
+template<typename Thunk>
+int ffi_guard_thunk(const char* func_name, Thunk thunk)
+   {
+   try
+      {
+      return thunk();
+      }
+   catch(std::bad_alloc)
+      {
+      return ffi_error_exception_thrown(func_name, "bad_alloc");
+      }
+   catch(std::exception& e)
+      {
+      return ffi_error_exception_thrown(func_name, e.what());
+      }
+   catch(...)
+      {
+      return ffi_error_exception_thrown(func_name, "unknown exception");
+      }
+
+   return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
+   }
+
+template<typename T, uint32_t M, typename F>
+int apply_fn(botan_struct<T, M>* o, const char* func_name, F func)
+   {
+   try
+      {
+      if(!o)
+         throw FFI_Error("Null object to " + std::string(func_name));
+      if(T* t = o->get())
+         return func(*t);
+      }
+   catch(std::bad_alloc)
+      {
+      return ffi_error_exception_thrown(func_name, "bad_alloc");
+      }
+   catch(std::exception& e)
+      {
+      return ffi_error_exception_thrown(func_name, e.what());
+      }
+   catch(...)
+      {
+      return ffi_error_exception_thrown(func_name, "unknown exception");
+      }
+
+   return BOTAN_FFI_ERROR_UNKNOWN_ERROR;
+   }
+
+#define BOTAN_FFI_DO(T, obj, param, block)                              \
+   apply_fn(obj, BOTAN_CURRENT_FUNCTION,                                \
+            [=](T& param) -> int { do { block } while(0); return BOTAN_FFI_SUCCESS; })
+
+template<typename T, uint32_t M>
+int ffi_delete_object(botan_struct<T, M>* obj, const char* func_name)
+   {
+   try
+      {
+      if(obj == nullptr)
+         return BOTAN_FFI_SUCCESS; // ignore delete of null objects
+
+      if(obj->magic_ok() == false)
+         return BOTAN_FFI_ERROR_INVALID_INPUT;
+
+      delete obj;
+      return BOTAN_FFI_SUCCESS;
+      }
+   catch(std::exception& e)
+      {
+      return ffi_error_exception_thrown(func_name, e.what());
+      }
+   catch(...)
+      {
+      return ffi_error_exception_thrown(func_name, "unknown exception");
+      }
+   }
+
+#define BOTAN_FFI_CHECKED_DELETE(o) ffi_delete_object(o, BOTAN_CURRENT_FUNCTION)
+
+inline int write_output(uint8_t out[], size_t* out_len, const uint8_t buf[], size_t buf_len)
+   {
+   const size_t avail = *out_len;
+   *out_len = buf_len;
+
+   if(avail >= buf_len)
+      {
+      Botan::copy_mem(out, buf, buf_len);
+      return BOTAN_FFI_SUCCESS;
+      }
+   else
+      {
+      Botan::clear_mem(out, avail);
+      return BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE;
+      }
+   }
+
+template<typename Alloc>
+int write_vec_output(uint8_t out[], size_t* out_len, const std::vector<uint8_t, Alloc>& buf)
+   {
+   return write_output(out, out_len, buf.data(), buf.size());
+   }
+
+inline int write_str_output(uint8_t out[], size_t* out_len, const std::string& str)
+   {
+   return write_output(out, out_len,
+                       reinterpret_cast<const uint8_t*>(str.c_str()),
+                       str.size() + 1);
+   }
+
+inline int write_str_output(char out[], size_t* out_len, const std::string& str)
+   {
+   return write_str_output(reinterpret_cast<uint8_t*>(out), out_len, str);
+   }
+
+inline int write_str_output(char out[], size_t* out_len, const std::vector<uint8_t>& str_vec)
+   {
+   return write_output(reinterpret_cast<uint8_t*>(out), out_len,
+                       reinterpret_cast<const uint8_t*>(str_vec.data()),
+                       str_vec.size());
+   }
+
+}
+
+#endif