kc3-lang/dlfcn-win32/CMakeLists.txt

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• Hash : 29c46a54
  Author :
  Date : 2019-01-29T22:38:42
  

  Fix resolving global symbols when LoadLibrary() is called after dlopen() Usage of first_automatic_object cache is wrong. This cache is filled by all loaded DLL files (either implicitly or explicitly with LoadLibrary() call) by EnumProcessModules() call at first usage of dlopen(). So dlsym() can resolve global symbols only if they were loaded prior to dlopen() call. Any future usage of LoadLibrary() does not include newly loaded DLLs into first_automatic_object cache. To fix this problem, first_automatic_object cache is fully removed and EnumProcessModules() call is issued directly in dlsym() call. As EnumProcessModules() returns all DLLs, included those which were loaded by dlopen() with RTLD_LOCAL, it may break RTLD_LOCAL support. To address this problem switch linked-list of all loaded DLLs with RTLD_GLOBAL to linked-list of all loaded DLLs with RTLD_LOCAL flag. And then skip modules from EnumProcessModules() which are in linked-list. Also in WinAPI all DLLs loaded by LoadLibrary() behaves like RTLD_GLOBAL. So above change is compatible with this behavior. There may be another problem. Before retrieving HMODULE for DLL filename (which is done by LoadLibrary()), it is not possible to detect if DLL was already loaded by RTLD_LOCAL or not. And after calling LoadLibrary() it is not possible to know if DLL was loaded either by dlsym() with RTLD_LOCAL or by LoadLibrary() (which is equivalent to RTLD_GLOBAL). To address this problem, compare number of loaded modules (counted by EnumProcessModules()) before and after LoadLibrary() called from dlsym(). If number does not change it means that DLL was already loaded. So based on this result either add or remove HMODULE from linked-list of RTLD_LOCAL modules. Added test demonstrate usage of: global = dlopen(NULL, RTLD_GLOBAL); /* global handle */ LoadLibrary("library.dll"); /* this provides function */ function = dlsym(global, "function"); /* resolve function from library.dll */

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• CMakeLists.txt

• cmake_minimum_required(VERSION 2.8)
  
  if (NOT DEFINED CMAKE_BUILD_TYPE)
    set (CMAKE_BUILD_TYPE Release CACHE STRING "Build type")
  endif ()
  
  project (dlfcn-win32 C)
  
  option(BUILD_SHARED_LIBS "shared/static libs" ON) 
  option(BUILD_TESTS "tests?" OFF)
  
  set(headers dlfcn.h)
  set(sources dlfcn.c)
  
  if (BUILD_SHARED_LIBS)
    add_definitions(-DSHARED)
  endif (BUILD_SHARED_LIBS)
  
  add_library(dl ${sources})
  target_link_libraries(dl psapi)
  
  install (TARGETS dl EXPORT dlfcn-win32-targets
                      RUNTIME DESTINATION bin
                      LIBRARY DESTINATION lib${LIB_SUFFIX}
                      ARCHIVE DESTINATION lib${LIB_SUFFIX})
  
  install (FILES ${headers} DESTINATION include)
  
  # If CMake version is greater than or equal to 2.8.11
  # also install the cmake configuration files to simplify
  # the use of dlfcn-win32 in CMake
  if(NOT ${CMAKE_VERSION} VERSION_LESS "2.8.11")
      # Correctly export the location of installed includes in the target 
      target_include_directories(dl INTERFACE $<INSTALL_INTERFACE:include>)
  
      # Export the targets  (build tree)
      export(EXPORT dlfcn-win32-targets
             FILE "${CMAKE_CURRENT_BINARY_DIR}/dlfcn-win32-targets.cmake"
             NAMESPACE dlfcn-win32::
      )
      
      # Write the CMake config file
      set(CMAKE_CONF_INSTALL_DIR share/dlfcn-win32)
      set(INCLUDE_INSTALL_DIR include)
      include(CMakePackageConfigHelpers)
      configure_package_config_file(dlfcn-win32-config.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/dlfcn-win32-config.cmake
                                    INSTALL_DESTINATION ${CMAKE_CONF_INSTALL_DIR}
                                    PATH_VARS INCLUDE_INSTALL_DIR
                                    NO_CHECK_REQUIRED_COMPONENTS_MACRO)
  
      # Install the targets (install)
      install(EXPORT dlfcn-win32-targets
              FILE dlfcn-win32-targets.cmake
              NAMESPACE dlfcn-win32::
              DESTINATION ${CMAKE_CONF_INSTALL_DIR})
  
      # Install the CMake config file
      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/dlfcn-win32-config.cmake
              DESTINATION ${CMAKE_CONF_INSTALL_DIR})
  endif()
  
  if (BUILD_TESTS)
    enable_testing()
    add_library(testdll SHARED testdll.c)
    set_target_properties(testdll PROPERTIES PREFIX "")
    add_library(testdll3 SHARED testdll3.c)
    set_target_properties(testdll3 PROPERTIES PREFIX "")
    add_executable(t_dlfcn test.c)
    target_link_libraries(t_dlfcn dl)
    add_test (NAME t_dlfcn COMMAND t_dlfcn)
  endif ()
  

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