4. Debugging

4.1 Debugging with gdbserve.nlm

There is some rather limited debugging functionality available by using a serial cable between the Netware box and the Linux host.

On the Netware box you need to run a compiler stub called gdbserve.nlm. It will start the program to be compiled and open the serial port. On the Linux host you will run i386-netware-gdb and tell it to use the serial line to access the compilation target. However there are certain problems with gdbserve.nlm:

• It does not work reliable.
• It does not work in a protected memory space.
• The Netware machine needs to be rebooted after debugging using a reset.
• gdbserve.nlm stops anything else on the machine.
• It cannot be compiled using our cross-compiler, since the cross-compiler is based on the Netware libc package, but gdbsrv.nlm needs the older clib environment plus the aio package downloadable for free from Novell for compilation. I have developed a patch that makes it compile, however the resulting binary does not work. For that reason I've shipped gdbserve.nlm in binary form in the cross_nlm-1.2.0.tar.gz download.

4.1.1 Preparing the program

• The program needs to be created with debug infos. You need to use the -g compiler switch to gcc/g++, the -ggdb switch does not work (supposed to be a bug somewhere in the linker script).
• Do not use the -s or -strip command line option when linking the NLM.

The NLM on the Netware box does not need to include debug infos. Only the copy of the NLM used on the Linux box for debugging needs to include debug infos. Removing debug infos from an already created NLM with i386-netware-strip seems to result in a a broken NLM. Use the -s linker switch as a workaround if you need a stripped binary.

4.1.2 Preparing the Netware box

• Connect Linux box and Netware box using a serial cable.
• Copy both the gdbserve.nlm and the application to be debugged to the Netware box. Usually you'll use a ncpmount to do so.
• Start gdbserve on the Netware box using a command like:

           set Cpu Hog Amount = 0
           sys:\tmp\gdbserve sys:\tmp\hello.nlm
  

4.1.3 Using gdb

• Start i386-netware-gdb using the NLM-Filename as the command line parameter.

          i386-netware-gdb hello.nlm
  

• Tell gdb to connect to the remote side using a serial cable

          target remote /dev/ttyS0
  

• Instead of ``run''ing the program, use ``cont'' to continue the execution.

          break main
          cont
  

4.2 Using gdb2ndi

There is an alternative approach to debugging on Netware by Armin Diehl: http://home.arcor.de/armin.diehl/fpcnw/gdbnw.html . I have not tried that yet. The main advantage seems to be that it works with TCP/IP.

4.3 The Netware integrated debugger

http://developer.novell.com/ndk/doc/clib/index.html?page=/ndk/doc/clib/ndev_enu/data/hqelnt4z.html

There is also some parameter to server.exe that enables development features, no idea what that is good for yet.