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  NetWare Loadable Module Programming HOWTO
  Martin Hinner, <>
  Version 0.3, 04 January 2007

  This document describes how to develop NetWare Loadable Modules under
  Linux, using GNU CC and nlmconv(1) from GNU binutils. This is not an
  official Novell document; I wrote it without any help or cooperation
  from Novell, Inc.. Please note that Novell Netware is becoming quite
  obsolete nowadays. In fact I have not updated this howto for more than
  five years till now (2007).

  Table of Contents

  1. Introduction
     1.1 C++ Development
     1.2 Related Documentation
     1.3 Copying
     1.4 Contacting the author

  2. Setting Up Your Linux Box and NetWare Server
     2.1 Novell NetWare Server
     2.2 Linux Box With IPX/NCPFS
     2.3 GNU C Compiler
     2.4 nlmconv(1) from GNU binutils
     2.5 The nlm-kit Package
     2.6 Include Files and Documentation from the NDK
     2.7 Access to the NetWare Server (Xconsole or rconsole)

  3. First Step: Hello world
     3.1 hello.c - Source File
     3.2 hello.def - NLM header file
     3.3 Makefile
     3.4 GCC problems
     3.5 Testing the Module

  4. NLM Header file
     4.2 CHECK
     4.3 CODESTART
     4.4 COPYRIGHT
     4.5 CUSTOM
     4.6 DATASTART
     4.7 DATE
     4.8 DEBUG
     4.10 EXIT
     4.11 EXPORT
     4.12 FLAG_OFF
     4.13 FLAG_ON
     4.14 HELP
     4.15 IMPORT
     4.16 INPUT
     4.17 MAP
     4.18 MESSAGES
     4.19 MODULE
     4.20 MULTIPLE
     4.21 NAMELEN
     4.22 OS_DOMAIN
     4.23 OUTPUT
     4.24 PATH
     4.26 REENTRANT
     4.27 SCREENNAME
     4.28 SHARELIB
     4.29 STACK
     4.30 STACKSIZE
     4.32 START
     4.34 THREADNAME
     4.35 TYPE
     4.36 VERSION
     4.37 XDCDATA

  5. Message files
  6. Help Files
  7. XDC Data Files
  8. Header Files (.h)
  9. Import Files (.imp)
     9.1 Generating Import Files Using nlmimp(1)


  1.  Introduction

  NetWare Loadable Modules (NLMs) are programs which run on Novell
  NetWare server. NLMs become part of the NetWare OS. You can load and
  unload NLMs while the server is running.

  "Official" compilers for NLMs are:

  �  Watcom C/C++

  �  Metrowerks Codewarrior for NetWare (see

  �  EPC C/C++ (see  <>)

  �  Novell NLMLINK.EXE

  (On a side note, NetWare 5 can also load 32bit DLLs, which can be
  built using Microsoft Visual C++, Borland C++ and other Windows
  compilers. For more information see

  This document describes how to get started with NLM development under
  Linux (and possibly other Unixes). Please note that this project is in
  very early stages of development, so a lot of things may not work as
  you'd expect.

  This document assumes that you are familiar with Novell NetWare, and
  that you have at least basic knowledge of writing NLMs. For more
  information about writing NLMs, see Novell's developer site,
  <>. You should also have experience with
  Unix and C/C++ programming with GNU CC. You can find a lot of
  information about this topic at  <>.

  1.1.  C++ Development

  As far as I know, C++ development with gcc is currently impossible,
  till somebody ports at least the libstdc++ and libgcc libraries from
  the gcc package.

  1.2.  Related Documentation

  Other documents that might be useful are:

  �  The IPX-HOWTO, which describes the details of configuring IPX
     protocol on Linux.

  �  The Linux GCC HOWTO, which covers how to set up the GNU C compiler
     and development libraries under Linux, and gives an overview of
     compiling, linking, running and debugging programs under it.

  �  The Assembly HOWTO, which describes how to program in assembly
     language using FREE programming tools, focusing on development for
     or from the Linux Operating System on the i386 platforms.

  �  The Creating NLMs on Linux x86,
     HOWTO.html>, by Gabor Keresztvalvi <>. His page
     describes the same thing as my HOWTO.  I found Gabor's page ten
     days after releasing version 0.1 of this document :( .

  1.3.  Copying

  Copyright (c) 2000 Martin Hinner, <>,

  This HOWTO is Free documentation; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of the
  License, or (at your option) any later version.

  This document 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
  General Public License for more details.

  You can obtain a copy of the GNU General Public License by writing to
  the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,

  1.4.  Contacting the author

  You can contact me at I welcome any suggestions
  and corrections, but please before you ask a question, try searching
  the internet first.  You should also check my homepage (
  <>) for any updates or additional
  information.  Please note that I am very busy with my other projects
  (like automotive diagnostics, ARM-based microprocessors development
  tools) and I have a full time job (I am working for SECONS Ltd. and
  Fintera Ltd.).

  2.  Setting Up Your Linux Box and NetWare Server

  You need to install and configure these things for NLM development:

  �  Linux box with configured IPX and NCPFS

  �  GNU C compiler (gcc) for elf-i386 (nearly all i386 Linux
     Distributions include it)

  �  GNU binutils with nlmconv(1) program

  �  My nlm-kit package

  �  Novell Developer Kit - NDK (include files and documentation)

  �  DOSemu (with rconsole) or X11 server for running NetWare Xconsole.


  You might also want to download the nlm-examples package from my FTP
  site: <> or
  2.1.  Novell NetWare Server

  Let's start with the NetWare server. You can use NetWare versions 3.X,
  4.X or 5.X.  NetWare 5 (or 5.1) three user "demo" version can be
  ordered from Novell Inc. for a few dollars. Don't be confused with
  word "demo", it's fully functional NetWare, except that it is limited
  to three users. By the way, this license can be upgraded online, at no
  cost, to five users. You might also try asking your local Novell
  partner for demo CDs (they may be free).

  2.2.  Linux Box With IPX/NCPFS

  You need to recompile your kernel with "The IPX protocol" and "NCP
  file system support" options enabled. Don't forget to say YES to "NDS
  authentication support" if you are using the NDS. Then you must
  configure the IPX protocol and mount your NetWare server volumes.
  Make sure that you have installed the ncpfs package! I use this


  ipx_interface delall
  ipx_interface add -p eth0 802.2 120 # Frame Ethernet_802.2, ipx net num 120
  insmod ncpfs                        # I have NCPfs compiled as module
  ncpmount -U admin -S elf -P XYZ /nw # mount all ELF's volumes as /nw

  For more information about configuring IPX and NCPFS, see the IPX-

  2.3.  GNU C Compiler

  I think that all modern Linuxes for the Intel x86 include gcc, which
  generates ELF32/i386 object files. If you have an older Linux
  distribution, it may use the a.out format instead of ELF. If your
  Linux doesn't use ELF, get and install a newer gcc.

  2.4.  nlmconv(1) from GNU binutils

  The nlmconv(1) utility links object files to the NLM format. It is a
  standard part of GNU binutils, but unfortunately it is not included in
  current distributions (RedHat, SuSE, Debian, ...). Get the binutils
  sources from, and compile them, or simply use the pre-
  compiled nlmconv from my nlm-kit package.

  2.5.  The nlm-kit Package

  My nlm-kit package is avaliable from
  <>. It contains necessary files
  for NLM development. Extract it and run "make all" and "make install".
  It will create the directory /usr/nwsdk/ and install all import files,
  object files and the nlmimp(1) utility.

  2.6.  Include Files and Documentation from the NDK

  Getting the NDK is easy:

  �  Download it from  <>.

  �  Order two NDK CDs from Novell.

  �  Get these CDs at no cost at BrainShare, Novell Developer Workshop
     or at other Novell Developer events.

  You need these files from the NDK (all are available online at

  �  C language header and import files (cdrom:\files\download\clib.exe)

  �  C language API documentation (cdrom:\files\download\clib_doc.exe)

  �  C language samples (optional)

  It's a pity that all the files mentioned above are InstallShield Win32
  executables.  You must find some Windows machine to extract them and
  then copy the include files to /usr/nwsdk/include/ and
  documentation/samples to anywhere you want.  The Novell License
  doesn't allow me to distribute include files or documentation with the

  Because the NDK include files don't work under Linux, you need to
  patch them manually by typing "make install-include" in the nlm-kit-
  X.Y/ directory.

  2.7.  Access to the NetWare Server (Xconsole or rconsole)

  You can access the NetWare server console directly (keyboard and
  monitor), using rconsole.exe (from dosemu), or using
  telnetd.nlm/Xconsole (you need X server for this).

  3.  First Step: Hello world

  As usual, we will start with the famous "Hello world" program. The
  source code for hello.nlm is available in the nlm-samples package. You
  can download it from  <>.

  3.1.  hello.c - Source File

  #define N_PLAT_NLM                                /* Define dest. platform */

  #include <nwconio.h>                              /* ConsolePrintf */

  main (int argc, char **argv)
    int i;

    ConsolePrintf ("\rHello world!\n\n");           /* print on system console */

    ConsolePrintf("Arguments:\n");                  /* all arguments */
    for (i=0;i<argc;i++)
     ConsolePrintf("argv[%u]=\"%s\"\n",i, argv[i]);

    return 0;                                       /* exit NLM */

  3.2.  hello.def - NLM header file

  # hello.def - NLM Header definition file for nlmconv(1)
  # Copyright (c) 2000 Martin Hinner <>

  # define startup object files
  INPUT   hello.o
  INPUT   /usr/nwsdk/lib/prelude.o            # clib startup code

  # all imported functions and import lists
  IMPORT @/usr/nwsdk/imports/clib.imp         # Functions in CLIB.NLM
  IMPORT @/usr/nwsdk/imports/threads.imp      # Functions in THREADS.NLM

  # NLM header...
  OUTPUT  hello.nlm                           # output file
  TYPE 0                                      # Ordinary NLM
  VERSION 1,0,0                               # Version 1.0
  COPYRIGHT "Copyright (c) 2000 Martin Hinner <>" # (c) ...
  DESCRIPTION "Simple 'Hello world' NLM module." # title of nlm
  SCREENNAME "System Console"                 # Default screen name

  MODULE CLIB,THREADS                         # req'd modules

  3.3.  Makefile

  # makefile for "hello world" NLM

  CC = gcc
  CFLAGS = -Wall -O2 -g -I/usr/nwsdk/include/ -nostdinc -fno-builtin -fpack-struct

  hello.nlm:      hello.o hello.def
          nlmconv --output-target=nlm32-i386 -T hello.def

  hello.o:        hello.c
          $(CC) $(CFLAGS) -c hello.c

  3.4.  GCC problems

  You must pass these arguments to the gcc:

  �  -fno-builtin: GCC's fast builtin functions sometimes cause server
     to abend, so we don't want to use them.

  �  -nostdinc: Only include files in /usr/nwsdk/include are valid for
     NLMs (don't forget to use also -I/usr/nwsdk/include).

  �  -fpack-struct: GCC's struct packing method is not valid for Novell
     NetWare, so we won't use it. Thanks to Gabor Keresztvalvi for this

  �  -fno-canary-all-functions: If you have Immunix StackGuard GCC, we
     don't want to use it. StackGuard doesn't work under NetWare.

  3.5.  Testing the Module

  Copy hello.nlm to the SYS:\SYSTEM directory on your NetWare server.
  Then, on the system console, type "load hello.nlm". If everything went
  fine, you should see NLM version information, a copyright message and
  "Hello world".

  4.  NLM Header file

  The NLM header file contains information for nlmconv(1). Each line
  contains one option or directive; everything after "#" is comment.
  This chapter describes all options and directives.

  This chapter is not yet finished, sorry.




  4.2.  CHECK


  CHECK <check procedure name>

  This directive specifies the function to be executed when the NLM is
  unloaded using the UNLOAD Server console command. If this function
  returns zero, the NLM can be unloaded, else the NLM is not ready to be


  CHECK CheckUnload



  CODESTART <map file code start offset>

  Map file start offset may be decimal or Xhex.



  COPYRIGHT ["Copyright string"]

  The copyright string is displayed on the server console screen when
  the NLM is loaded. If this option is not used, no copyright
  information is displayed.


  COPYRIGHT "Copyright (c) 1998 ABC Inc."

  4.5.  CUSTOM


  CUSTOM <custom data file path>



  DATASTART <map file data start offset>

  Map file data start offset may be decimal or Xhex.

  4.7.  DATE


  DATE <month, day, year>

  4.8.  DEBUG



  This directive tells the nlmconv(1) to include debugging information
  in the NLM file.





  DESCRIPTION "NLM Description String"

  4.10.  EXIT


  EXIT <exit procedure name>

  4.11.  EXPORT


  EXPORT <symbol list>

  EXPORT @<symbol list file>

  4.12.  FLAG_OFF


  FLAG_OFF <decimal number>

  4.13.  FLAG_ON


  FLAG_ON <decimal number>

  4.14.  HELP


  HELP <help file path>

  4.15.  IMPORT


  IMPORT <symbol list>

  IMPORT @<symbol list file>

  4.16.  INPUT


  INPUT <object file> [, <object file> [, ...] ]

  INPUT @<object list file>

  This directive lists the input ELF (.o) object files that are to be
  linked.  You can also list the object files in the list file, each
  object file on one line.


  INPUT @objectfiles.txt
  INPUT main.o
  INPUT /usr/nwsdk/lib/prelude.o

  4.17.  MAP


  MAP [map file name]

  4.18.  MESSAGES


  MESSAGES <message file path>

  4.19.  MODULE


  MODULE <autoload NLM list>

  4.20.  MULTIPLE



  4.21.  NAMELEN


  NAMELEN <decimal number>

  Default is 31. Zero is no limit.

  4.22.  OS_DOMAIN



  4.23.  OUTPUT


  OUTPUT <target file name>

  4.24.  PATH


  PATH  [search path;...]





  4.26.  REENTRANT





  SCREENNAME "Initial Screen Name (CLIB)"

  4.28.  SHARELIB


  SHARELIB <shared library path>

  4.29.  STACK


  STACK <stack size>

  4.30.  STACKSIZE


  STACKSIZE <stack size>



  STAMPEDDATA "Stamp" <data file path>

  Stamp is 8 char max.

  4.32.  START


  START <start procedure name>

  Default is _Prelude.






  THREADNAME "Initial Process Name (CLIB)"

  4.35.  TYPE


   TYPE <version>

  This directive specifies the format (NLM, LAN, DSK, NAM) of the NLM
  file to be generated. Valid values are:

  �  0 - NLM

  �  1 - LAN

  �  2 - DSK

  �  3 - NAM


  TYPE 0

  4.36.  VERSION


  VERSION <major version>, <minor version> [, <revision>]

  The version information is displayed on the server system console when
  the NLM loads. The major and minor version numbers can be 0 - 99. The
  revision can be 0 - 26 ("a" - "z") and is optional. The version
  directive is required.



  4.37.  XDCDATA


  XDCDATA <XDC data file path>

  5.  Message files

  A message file contains (as you guess) text messages generated by the
  NLM. You can create it using DOS programs MSGLIB.EXE and MSGMAKE.EXE.
  I don't know any similar utility for Unix. Sorry, you'll have to use
  dosemu or DOS machine :-(

  6.  Help Files

  Help files contain help for use with the NWSNUT user interface
  library.  There is no known Linux utility for creating help files. You
  must use the DOS program HELPLIB.EXE, which is available from Novell
  developer site.

  7.  XDC Data Files

  XDC files are used by NetWare 5 (or SMP NetWare 4.x), and store
  information about symmetric multiprocessing (SMP). You will probably
  not need them. At least not now :-) Again, there is no Unix utility
  for creating XDC files, you will have to use the MPKXDC.EXE program
  (also available on the Novell developer site).

  8.  Header Files (.h)


  9.  Import Files (.imp)


  9.1.  Generating Import Files Using nlmimp(1)

  Program nlmimp(1) is part of my nlm-kit package. (todo)

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