

  1. About PEStub

   PEStub may be used to replace the stub file of a PE executable.
  The replacement is done by typing:

   PESTUB <name of executable to modify> <name of new stub>

   Main purpose of PEStub is to replace the current stub of
  Win32 console applications by stub DPMIST32.BIN. This stub
  is part of HX runtime and will, in conjunction with PE file
  loader DPMILD32 and its Win32 emulation dlls, enable this app
  to run in plain DOS provided that all Win32 functions used by 
  the app are properly emulated.

   A backup copy of the modified executable with extension .BAK
  will be written when PEStub modifies the file.

  ----------------------------------------------------------------
  PLEASE NOTE: It may be more conveniant now to use tool HXLDR32
  instead of PEStub to run Win32 console applications in plain dos.
  HXLDR32 is loaded resident, does the same job as stub DPMIST32
  and does NOT require to modify existing PE executables.
  ----------------------------------------------------------------

  2. PE Loader Compatibility Test
  
   The HX PE loader has some restrictions which may prevent it
   from successfully loading a PE binary. PEStub knows (some of) these
   restrictions and can be used to check if 
   
   -  the binary has a chance to run with DPMILD32
   -  can successfully be modified by PEStub
   
   To start a check, run PEStub with option -r (and possibly option
   -v). If warnings are displayed the binary cannot be loaded with
   the current loader. If no warnings are displayed, there is still
   no guarantee that the binary will be loaded, it's just that the
   loader most likely won't get in the way. The binary may 
   use an API not emulated (yet) or only partly emulated or many
   other reasons. To be sure you will have to launch the loader.
   
  
  3. Verifying a PE executable can run in plain DOS

   To verify the application can be loaded in plain DOS enter:

   DPMILD32 <name of PE executable>

   This should be done in plain DOS as well, because the built-in
  windows DPMI server has some severe restrictions (this is valid
  for both win9x and winnt platforms). So it is not possible to
  load a PE executable without relocation info in this environment,
  because the loader cannot allocate memory with a specific base
  address (0x400000 in this case).

  If the console app was able to run one may enter:

   PEStub.exe <name of PE-executable>

   This will exchange the stub of the executable by default stub
  DPMIST32.BIN. The modified binary remains a valid Win32 executable,
  so nothing will change while running it in a Win32 environment.
   When running in native DOS it has to be ensured that the HX runtime
  binaries are located in a directory being included in your PATH
  environment variable.


  4. Known Problems
  
   If the new stub written to a binary is larger than the old one,
  the binary may become unloadable by the Windows NT/XP loader. On
  these systems the header may not become larger than the lowest RVA
  in the section table (error message is "access denied"). This should
  be no issue with DPMIST32.BIN, which just is 200h bytes long, but
  may be a problem if the new stub is to be DPMILD32.BIN.
   
  
  5. History
  
  2009/01/20: V2.9
  
  þ source assembled with JWasm.

  2007/03/18: V2.8
  
  þ bugfix: V2.7 didn't work.
  
  2007/03/15: V2.7
  
  þ additional infos displayed with option -v.
  þ remainings of a section cleared with zeroes.
  þ -q and -w options added.
  
  2006/07/18: V2.6
  
  þ now linked with POLINK. Some sections merged to reduce size.
  
  2006/03/19: V2.5
  
  þ bugfix: final binary had a bug in its malloc function.
  
  2006/03/13: V2.4
  
  þ small size reduction
  þ now using WriteFile, not WriteConsole for displays
  
  2005/12/27: V2.3
  
  þ additional check if RVA of a section is beyond image size. This works
    with windows, but does not with HX.
    
  2005/11/24: V2.2  
  
  þ bugfix: warning "relocs stripped" was ignored and the binary patched
    nevertheless.
    
  2005/07/12: V2.1  
  
  þ bugfix: don't tell the binary is compatible if it isn't found.
  
  2005/06/28: V2.0  
  
  þ OptionalHeader.SizeOfHeader doesn't tell the truth in any case (UPX
    packed binaries for example). This caused invalid binaries being created
    by PEStub.
  þ new command line options -v, -r, and -s.
  þ warning displayed if cmdline switch -x was set and relocation infos
    are missing.
                     
  2004/11/13: V1.9  
  
  þ name of new stub is optional, default is DPMIST32.BIN.
  
  2004/10/13: V1.8  
  
  þ new command line switch -x.

  
  6. Licence

  PEStub is part of HX DOS extender. This extender is freeware.
  View HXRT.TXT for licence details.

  Japheth
