dyn_load.cpp

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/*
* Dynamically Loaded Object
* (C) 2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#include <botan/dyn_load.h>
#include <botan/exceptn.h>
 
#if defined(BOTAN_TARGET_OS_HAS_POSIX1)
  #include <dlfcn.h>
#elif defined(BOTAN_TARGET_OS_HAS_WIN32)
  #define NOMINMAX 1
  #define _WINSOCKAPI_ // stop windows.h including winsock.h
  #include <windows.h>
#endif
 
namespace Botan {
 
namespace {
 
void raise_runtime_loader_exception(const std::string& lib_name,
                                    const char* msg)
   {
   const std::string ex_msg =
      "Failed to load " + lib_name + ": " +
      (msg ? msg : "Unknown error");
 
   throw System_Error(ex_msg, 0);
   }
 
}
 
Dynamically_Loaded_Library::Dynamically_Loaded_Library(
   const std::string& library) :
   m_lib_name(library), m_lib(nullptr)
   {
#if defined(BOTAN_TARGET_OS_HAS_POSIX1)
   m_lib = ::dlopen(m_lib_name.c_str(), RTLD_LAZY);
 
   if(!m_lib)
      raise_runtime_loader_exception(m_lib_name, ::dlerror());
 
#elif defined(BOTAN_TARGET_OS_HAS_WIN32)
   m_lib = ::LoadLibraryA(m_lib_name.c_str());
 
   if(!m_lib)
      raise_runtime_loader_exception(m_lib_name, "LoadLibrary failed");
#endif
 
   if(!m_lib)
      raise_runtime_loader_exception(m_lib_name, "Dynamic load not supported");
   }
 
Dynamically_Loaded_Library::~Dynamically_Loaded_Library()
   {
#if defined(BOTAN_TARGET_OS_HAS_POSIX1)
   ::dlclose(m_lib);
#elif defined(BOTAN_TARGET_OS_HAS_WIN32)
   ::FreeLibrary((HMODULE)m_lib);
#endif
   }
 
void* Dynamically_Loaded_Library::resolve_symbol(const std::string& symbol)
   {
   void* addr = nullptr;
 
#if defined(BOTAN_TARGET_OS_HAS_POSIX1)
   addr = ::dlsym(m_lib, symbol.c_str());
#elif defined(BOTAN_TARGET_OS_HAS_WIN32)
   addr = reinterpret_cast<void*>(::GetProcAddress((HMODULE)m_lib, symbol.c_str()));
#endif
 
   if(!addr)
      throw Invalid_Argument("Failed to resolve symbol " + symbol +
                             " in " + m_lib_name);
 
   return addr;
   }
 
}