newscache: Thread: Backtrace child process - was: Newscache on Freebsd

Steve Ames wrote:

>Done and done. I'm still not sure how to get a backtrace. Adding
>--enable-debug didn't seem to add any extra debugging.
>
>
>  
>
***### Backtrace: i have tried the following sequenz to debug a child 
process under linux.

1) start the newscache server process with newscache
2) less /var/log/news.log (see /etc/syslog.conf for this settings)
3) simulate a client access with telnet localhost 119
4) you can obtain the PID in the news.log file
5) run gdb and attach to the client process with gdb newscache PID and 
type cont
6) type in the telnet session: list active
7) the segmenation fault should be seen in the gdb session. type bt and 
send the whole output to the newscache mailing list

I tested this sequenz on a RedHat 9 system and got with the standard 
settings (newscache.conf) user news group news the following error:

Attaching to program: /usr/sbin/newscache, process 2470
Couldn't get registers: Operation not permitted.
A program is being debugged already.  Kill it? (y or n)

--> The only way to get out of this situation is, to make a killall 
-KILL newscache. You can debug the child process, if you change the 
following parameters in /etc/newscache.conf
user root
group root

--> Don't forget to switch the parameters back and check the permissions 
on /var/cache/newscache!!

Further informations you can find on:

1) http://httpd.apache.org/dev/debugging.html
2) http://lists.ntop.org/pipermail/ntop-dev/2003-May/002793.html


***###  ./configure --enable-debug Output in news.log. For this test i 
set in /etc/syslog.conf
news.*       /var/log/news.log
and killall -HUP syslogd

In the original version of NewsCache 1.1.12 the -g option is always 
set(!?), also if you configured it without --enable-debug. You can see 
additional (a lot more) messages in the log, if you configure 
--enable-debug. See the attached news.log files.

HTH Herbert