GetProcAddress with all loaded libraries

Question

With dlopen you can provide NULL as the library name and get a handle that allows you to find a symbol in any of the loaded libraries:

If filename is a NULL pointer, then the returned handle is for the main program. When given to dlsym(), this handle causes a search for a symbol in the main program, followed by all shared libraries loaded at program startup, and then all shared libraries loaded by dlopen() with the flag RTLD_GLOBAL.

Can you do the same with GetProcAddress? I want to search for the presence of a Windows API but different libraries are loaded in Windows 8.

I know what libraries are loaded by looking in the COFF headers, I guess I could loop through the handles there...

This is the code I'm currently using:

.hpp

#include <string>
#include <stdexcept>

/**
 * @~english
 * Looks up a Windows API function. Make sure you set @c _WIN32_WINNT so that the definition is available at compile
 * time.
 * @par Example
 * @code
 * # undef _WIN32_WINNT
 * # define _WIN32_WINNT 0x600
 * # include <system/inc/nt/windows.h>
 * static const auto initialize_srw_lock_ptr = FunctionPtrLookup(InitializeSRWLock, "kernel32");
 * @endcode
 * @param function the function definition to lookup
 * @retval nullptr the function did not exist on this version of Windows
 * @returns a function pointer to invoke
 */
#define FunctionPtrLookup(function, library) \
  FunctionLookup<decltype(function)>(#function, library)

/**
 * @~english
 * The return type of FunctionLookup
 */
typedef void(*FunctionLookupPtr)();

/**
 * @~english
 * Looks up a Windows API function. 
 * @param name the name of the function to find in the library
 * @retval nullptr the function did not exist on this version of Windows
 * @returns a function pointer to invoke
 * @see FunctionPtrLookup
 */
FunctionLookupPtr FunctionLookup(const std::string& name, const std::string& library);

/// @copydoc FunctionLookup
template<typename Signature>
const Signature * FunctionLookup(const std::string& name, const std::string& library) {
  return reinterpret_cast<const Signature*>(FunctionLookup(name, library));
}

.cpp

FunctionLookupPtr FunctionLookup(const std::string& name, const std::string& library) {
  const auto wide_library = Utf8ToWide(library);
  const auto lib = LoadLibraryW(wide_library.c_str());
  if (!lib) {
    return nullptr;
  }
  return reinterpret_cast<FunctionLookupPtr>(GetProcAddress(lib, name.c_str()));
}

Ideally, I'd want to remove the library variable.

Answer 1

You can use EnumProcessModules to enumerate all loaded modules for current process, use example from here: http://msdn.microsoft.com/en-us/library/ms682621%28v=vs.85%29.aspx, if you call PrintModules with GetCurrentProcessId(), it will enumerate all HMODULE handles (value is in hMods[i]) for current process. You can use them with GetProcAddress to find your function.

You must be aware that its possible to find the same named functions in different dll-s, mostly you know dll name for WinAPI function.