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Make trisul core dump upon crash

If you need to debug a trisul crash, a core dump is a valuable tool.

Request a checked build​

The trisul executable that comes with the RPM or DEB package is stripped of debugging symbols. You can request Unleash Networks for a checked build, with all symbols intact. We will give you a file called trisul_checked built specifically for your platform.

Place the checked build in /usr/local/bin

Core file​

Trisul is a setuid program. It starts up as root, but after completing privileged work, drops down to the user specified in the <SetUID> parameter in trisulConfig.xml. The default user is trisul.trisul.

Enable core dumping of setuid programs​

Set the value of /proc/sys/fs/suid_dumpable to 2

[root@localhost ]# cat /proc/sys/fs/suid_dumpable  
0  
[root@localhost ]# echo 2 > /proc/sys/fs/suid_dumpable  
[root@localhost ]#  
[root@localhost ]# cat /proc/sys/fs/suid_dumpable  
2

Where is the core file ?​

By default The core file will be placed in /tmp and will be called core.xxxx where //xxxx// is the PID of the trisul process that crashed. You can change this filename by modifying the /etc/sysctl.conf file.

Add the following lines to /etc/sysctl.conf

pre..

1.  core file will be called core.trisul.2239  
    kernel.core\_pattern=/tmp/core.%e.%p

Reload config

pre..  
\[root@localhost \~\]\# sysctl -p  
net.ipv4.ip\_forward = 0  
…  
…  
kernel.core\_pattern = /tmp/core.%e.%p  
\[root@localhost \~\]\#

When it crashes​

Once Trisul crashes and you have located the core dump in /tmp, it is time to fire up gdb and determine the cause of the crash.

You must do this as root, because the saved core file is only readable by root.

pre..  
gdb /usr/local/bin/trisul\_checked /tmp/core.trisul.3297  
(gdb) bt  
.. prints the stack…

You may then send the stack trace to us so we can help fix the cause of the crash.