docs/docs/ftldns/debugging.md

Once you are used to it, you can skip most of the steps. Debugging FTLDNS is actually quite easy as pihole-FTL has been designed such that a debugger can be attached to an already running process. It can give you insights into how software (not limited to pihole-FTL) works.

1. Install screen and gdb using sudo apt-get install screen gdb
2. Start a screen session (it will allow you to come back even if the SSH connection died)

• If you don't know about screen, then read about it (you will love it!)

3. Start a screen session using screen
4. Use sudo gdb -p $(pidof pihole-FTL) to attach the debugger to the already running pihole-FTL process
5. Once loading of the symbols has finished (the (gdb) input prompt is shown), run handle SIGHUP nostop SIGPIPE nostop
6. Enter continue to continue operation of pihole-FTL inside the debugger. All debugger features are now available.
7. When pihole-FTL has crashed, copy&paste the terminal output into a (new) issue. Also type backtrace and include its output. We might ask for additional information in order to isolate your particular issue.