Executable source code (see in the file for compile command)

test_dlopen.c (text/plain), 1.57 KB, created by Andreas Fink on 2011-01-08 12:59:29 UTC

// g++ -ldl -o test_dlopen test_dlopen.c && ./test_dlopen ./libtest.so

#include <dlfcn.h>
#include <link.h>
#include <cstdio>
#include <iostream>

int cb(struct dl_phdr_info* info, size_t size, void* data)
{
  std::cout << info->dlpi_name << std::endl;
  return 0;
}

typedef void (*test_fct)();

int main(int argc, char** argv)
{
  const char* szLibPath = "./libtest.so";
  if ( argc > 1 ) {
    szLibPath = argv[1];
  }

  // dlopen the library and list all loaded libraries in memory
  void* pLibHandle = dlopen(szLibPath, RTLD_LAZY|RTLD_GLOBAL);
  std::cout << "-----------------------------------------------------------------------------------" << std::endl;
  std::cout << "Loaded libraries, after " << szLibPath << " has been loaded" << std::endl;
  dl_iterate_phdr(cb, 0);
  
  // dlclose the library and list again all closed libraries
  std::cout << "-----------------------------------------------------------------------------------" << std::endl;
  std::cout << "dlclose(pLibHandle) return value: " << dlclose(pLibHandle) << " (should return 0)" <<  std::endl;  // should return 0
  std::cout << "Loaded libraries after " << szLibPath << " has been closed..." << std::endl;
  dl_iterate_phdr(cb, 0);

  // the bug is here really visible, since a second dlcolse(pLibHandle) returns 0 although the library has been closed already
  std::cout << "-----------------------------------------------------------------------------------" << std::endl;
  std::cout << "dlclose(pLibHandle) return value: " << dlclose(pLibHandle) << " (should return -1)" << std::endl;  // should return -1

  return 0;
}