MemoryModule — loading DLL from memory (Delphi adaptation)

This code is Delphi translation of MemoryModule.c file by Joachim Bauch with addition of two helper units that enable using MM engine completely transparently.

Resource loading and exe loading, custom functions, user data not implemented yet.

Tested under RAD Studio XE2 and XE6 32/64-bit, Lazarus 32-bit. Demo project included.

Features in brief

With the MemoryModule engine you can store all required DLLs inside your binary to keep it standalone. Additional hook units allow transparent using of MM engine thus allowing switching MM/WinAPI loading as well as enabling 3rd party dynamic-load DLL interfaces that are unaware of MM (tested with Interbase Express components and Firebird client library).

In other words, you can do things like this

try
  ms := TMemoryStream.Create;
  ms.LoadFromFile(ParamStr(1));
  ms.Position := 0;
  lib := MemoryLoadLibary(ms.Memory);
  ms.Free;
  if lib = nil then Exit;

  func := TNativeUIntFunc(MemoryGetProcAddress(lib, PAnsiChar(AnsiString(ParamStr(2)))));
  if @func = nil then Exit;
  
  WriteLn(func);
finally
  MemoryFreeLibrary(lib);
end;

or even like this

if not InstallHook(@GetLibPtrProc) then
begin
  Writeln('Error installing hook');
  Exit;
end;

try
  ms := TMemoryStream.Create;
  ms.LoadFromFile(ParamStr(1));
  ms.Position := 0;
  lib := Pointer(LoadLibrary(PChar(ParamStr(1))));
  ms.Free;
  if lib = nil then Exit;

  func := TNativeUIntFunc(GetProcAddress(HMODULE(lib), PAnsiChar(AnsiString(ParamStr(2)))));
  if @func = nil then Exit;
  
  WriteLn(func);
finally
  FreeLibrary(HMODULE(lib));
  UninstallHook;
end;

See demo project for samples. Good testing sample of parameters is %WinDir%\System32\KernelBase.dll and GetCurrentThread. Note that kernel32.dll and some of the other Windows libraries couldn't be loaded with MM.

References

• Joahim's article
• TLS Callbacks
• PE description