[DEBUGGING 101] DEBUGGING 101 #debugging #101 #strace #fatrace #ptrace #haproxy #apache #php

DEBUGGING-101.md

HAPROXY

• Debug haproxy to see backend routing haproxy -f /path/to/haproxy.cfg -d

APACHE2

• List all threads of a process ps auxw -T | fgrep apache2

• Attach strace to those strace -fp $PID

• Strace all apache2 threads ps awux | grep sbin/apache | awk '{print"-p " $2}' | xargs strace -f

• Find all strings in a binary strings myfile

• Debug php application (or wordpress platform) php -S localhost:8080

• Enabling coredump

cat /usr/share/doc/apache2/README.backtrace
#https://ashout.com/enable-coredump-apache2-ubuntu/

• Replay apache2 logs

while read line
do
	REQUEST=$(echo ${line} | awk -F ' ' '{ print $8 }')
	curl -L "https://mytest.platform.local/$REQUEST"
done < access.log

#https://biig.fr/nous-sommes-inventifs/biigbox/deboguer-erreur-segfault-de-php