nwuser.DEBUG.txt

10/04/04

The NWUser preload library can be a problem to debug.  If there's a problem 
in it that causes it to crash during startup, you have no easy way to 
attach a debugger. 

In order to work around this, there's some #ifdef'd code inside of 
nwuser.c that will install signal handlers for SIGSEGV, SIGBUS, and 
(hopefully) dump stack traces on a crash. 

NOTE:  This debugging should only be used if NWUser crashes on startup. 
If you get into the game do not use this debugging. 

Generally, if NWUser crashes on startup, it _should_ crash for 
all programs, not just NWN, so you can use something as simple as
/bin/ls to debug NWUser issues. 

Note, it is preferrable to have GDB installed for this, as NWUser
spawns a copy of GDB to figure out what's going on. 

This code hasn't been extensively tested, but the general sequence is: 

$ cd somewhere
$ gzip -d -c nwuser-public.<release>.tar.gz | tar xvof -
$ cd nwuser
$ ./nwuser_install.pl crash
$ export LD_PRELOAD=`pwd`/nwuser.so
$ ls
$ 

If '/bin/ls' doesn't seem to crash NWUser, then try full NWN, however, I'd 
recommend changing NWN to run in windowed mode before trying, lest you leave
your windowing system in a bad state.    (See [Display Options] -> 
FullScreen/AllowWindowedMode in the NWN.INI file to change )  

In /tmp, you should now have three new files: 

/tmp/nwu_crash.log
/tmp/nwu_crash.cmd
/tmp/nwu_crash2.log

I will need the two *.log files.   The *.cmd file is just a temporary file
passed to GDB, to pull a stack trace, and may be deleted. 

nwu_crash.log is a stack trace generated by the backtrace() family of calls
in glibc.  Its not terribly useful, but it does give a place to start.  
It should be generated all the time.

nwu_crash2.log is a GDB generated stack trace.  Its also the 
most useful log file.   Unsurprisingly, if GDB is not installed, 
this files contents will not be useful. :-) 

Eitherway, email me what data you've collected, and I'll at least make
an attempt to look at it. 

David Holland
david.w.holland@gmail.com