kc3-lang/dlfcn-win32/testdll2.c

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• Hash : 63d7bda4
  Author :
  Date : 2019-01-29T22:57:04
  

  Implement support for dlsym() with RTLD_DEFAULT and RTLD_NEXT
  
  dlsym() with RTLD_DEFAULT handle behaves in same way like with global handle
  returned by dlopen() with NULL file name.
  
  dlsym() with RTLD_NEXT handle search for next loaded module which provides
  specified symbol. "Next" means module which in EnumProcessModules() result
  after the module which called dlsym().
  
  To get caller function of dlsym() use _ReturnAddress() intrinsic. To get
  module where is caller function use the fact that HMODULE is the same value
  as the module's base address.
  
  When compiling under gcc, defines _ReturnAddress() macro via gcc's builtin
  as it does not provide MSC's specific _ReturnAddress() intrinsic.
  
  Added tests demonstrate that both RTLD_DEFAULT and RTLD_NEXT are working as
  expected.
  

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• testdll2.c

• /*
   * dlfcn-win32
   * Copyright (c) 2007 Ramiro Polla
   * Copyright (c) 2019 Pali Rohár <pali.rohar@gmail.com>
   *
   * dlfcn-win32 is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * dlfcn-win32 is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with dlfcn-win32; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  #ifdef _DEBUG
  #define _CRTDBG_MAP_ALLOC
  #include <stdlib.h>
  #include <crtdbg.h>
  #endif
  #include <stdio.h>
  
  #include "dlfcn.h"
  
  #if defined(_WIN32)
  #define EXPORT __declspec(dllexport)
  #else
  #define EXPORT
  #endif
  
  EXPORT int function2( void )
  {
      char *error;
      int (*function2_orig)(void);
      printf( "Hello, world! from wrapper library\n" );
      function2_orig = dlsym(RTLD_NEXT, "function2");
      if (!function2_orig)
      {
          error = dlerror( );
          printf( "ERROR\tCould not get symbol from RTLD_NEXT handle: %s\n",
                  error ? error : "" );
          return 1;
      }
      if (function2_orig() != 0)
      {
          printf( "ERROR\tOriginal function from RTLD_NEXT handle did not return correct value\n" );
          return 1;
      }
      return 2;
  }
  

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