mhi@penguin.cz>Version 0.2, 04 August 2000
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.
server. NLMs become part of the !NetWare OS. You can load and unload NLMs while the server is running.
"Official" compilers for NLMs are:
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(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
http://developer.novell.com/ndk/dllcomp.htm)
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,
http://developer.novell.com/. 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
http://www.linuxdoc.org/.
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.
Other documents that might be useful are:
protocol on Linux. *
development libraries under Linux, and gives an overview of compiling, linking, running and debugging programs under it. *
program in assembly language using FREE programming tools, focusing on development for or from the Linux Operating System on the i386 platforms. *
http://home.sch.bme.hu/keresztg/novell/howto/NLM-Linux-HOWTO.html, by Gabor Keresztvalvi
<keresztg@mail.com>. His page describes the same thing as my HOWTO.
I found Gabor's page ten days after releasing version 0.1 of this document :( .
*
Copyright (c) 2000 Martin Hinner, < mhi@penguin.cz>.
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, USA.
You need to install and configure these things for NLM development:
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(nearly all i386 Linux Distributions include it) *
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You might also want to download the nlm-examples package from my FTP site:
ftp://ftp.penguin.cz/pub/users/mhi/nlm/ or
ftp://ftp.funet.fi/pub/mirrors/ftp.penguin.cz/pub/users/mhi/nlm/.
Let's start with the !NetWare server. You can use !NetWare versions 3.X, 4.X or 5.X.
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).
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 script:
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-HOWTO.
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.
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 ftp.gnu.org, and compile them, or simply use the pre-compiled nlmconv from my nlm-kit package.
My nlm-kit package is avaliable from
ftp://ftp.penguin.cz/pub/users/mhi/nlm/. 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.
Getting the NDK is easy:
http://developer.novell.com/ndk/.
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or at other Novell Developer events. *
You need these files from the NDK (all are available online at
http://developer.novell.com/ndk/clib.htm:
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*
*
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 nlm-kit.
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.
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).
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
ftp://ftp.penguin.cz/pub/users/mhi/nlm/.
int main (int argc, char **argv) { int i;
for (i=0;i<argc;i++)
return 0; /* exit NLM */ }
#
#
INPUT hello.o INPUT /usr/nwsdk/lib/prelude.o # clib startup code
IMPORT @/usr/nwsdk/imports/clib.imp # Functions in CLIB.NLM IMPORT @/usr/nwsdk/imports/threads.imp # Functions in THREADS.NLM
OUTPUT hello.nlm # output file TYPE 0 # Ordinary NLM VERSION 1,0,0 # Version 1.0 COPYRIGHT "Copyright (c) 2000 Martin Hinner <mhi@penguin.cz>" # (c) ... DESCRIPTION "Simple 'Hello world' NLM module." # title of nlm SCREENNAME "System Console" # Default screen name MODULE CLIB,THREADS # req'd modules
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
You must pass these arguments to the gcc:
GCC's fast builtin functions sometimes cause server to abend, so we don't want to use them. *
Only include files in /usr/nwsdk/include are valid for NLMs (don't forget to use also -I/usr/nwsdk/include). *
GCC's struct packing method is not valid for Novell !NetWare, so we won't use it. Thanks to Gabor Keresztvalvi for this information. *
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".
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.
Syntax:
AUTOUNLOAD
Syntax:
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 unloaded.
Example:
CHECK !CheckUnload?
Syntax:
CODESTART <map file code start offset>
Map file start offset may be decimal or Xhex.
Syntax:
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.
Example:
COPYRIGHT "Copyright (c) 1998 ABC Inc."
Syntax:
CUSTOM <custom data file path>
Syntax:
DATASTART <map file data start offset>
Map file data start offset may be decimal or Xhex.
Syntax:
DATE <month, day, year>
Syntax:
DEBUG
This directive tells the nlmconv(1) to include debugging information in the NLM file.
Example:
DEBUG
Syntax:
DESCRIPTION "NLM Description String"
Syntax:
EXIT <exit procedure name>
Syntax:
EXPORT <symbol list>
EXPORT @<symbol list file>
Syntax:
FLAG_OFF <decimal number>
Syntax:
FLAG_ON <decimal number>
Syntax:
HELP <help file path>
Syntax:
IMPORT <symbol list>
IMPORT @<symbol list file>
Syntax:
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.
Example:
INPUT @objectfiles.txt INPUT main.o INPUT /usr/nwsdk/lib/prelude.o
Syntax:
MAP [map file name?
Syntax:
MESSAGES <message file path>
Syntax:
MODULE <autoload NLM list>
Syntax:
MULTIPLE
Syntax:
NAMELEN <decimal number>
Default is 31. Zero is no limit.
Syntax:
OS_DOMAIN
Syntax:
OUTPUT <target file name>
Syntax:
PATH [search path;...?
for following CUSTOM, HELP, INPUT, MESSAGES, SHARELIB, STAMPEDDATA and XDCDATA.
Syntax:
PSEUDOPREEMPTION
Syntax:
REENTRANT
Syntax:
SCREENNAME "Initial Screen Name (CLIB)"
Syntax:
SHARELIB <shared library path>
Syntax:
STACK <stack size>
Syntax:
STACKSIZE <stack size>
Syntax:
STAMPEDDATA "Stamp" <data file path>
Stamp is 8 char max.
Syntax:
START <start procedure name>
Default is _Prelude.
Syntax:
SYNCHRONIZE
Syntax:
THREADNAME "Initial Process Name (CLIB)"
Syntax:
TYPE <version>
This directive specifies the format (NLM, LAN, DSK, NAM) of the NLM file to be generated. Valid values are:
*
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Example:
TYPE 0
Syntax:
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.
Example:
VERSION 1,5
Syntax:
XDCDATA <XDC data file path>
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 :-(
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.
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).
(todo)
(todo)
Program nlmimp(1)? is part of my nlm-kit package. (todo)
No other page links to HowToNLMHOWTO yet.
