signals

[ARaveala]

Signals to handle

• SIGINT
  cntrl +c , handle signal to shutdown gracefully and do any necessary clean up
• SIGTERM
  unlikey to be needed as this would require a kill pid command, however it will be worth exploring to see if it would be safer to handle it any way
• SIGHUP
  This is sent when a terminal session is disconnected , often affecting demonized processes ( since we are not allowed to fork it will not be deamonized)
  manual triggering is possible.
  only really required if we use config files, this will allow a graceful reloading of the config files incase of SIGHUP
  There may be a case where if we need server to restart that this is handled to reinitialize a global state as this can affect epoll()
• SIGPIPE
  prevent crashes by handling broken pipes, such as sending data to a client that is no longer available (closed socket)
  "MSG_NOSIGNAL in send() (Linux)." ?
• SIGSTP
  cntrl +z , this will pause the server , we may need to consider if pausing will cause problems with things like timeouts
• SIGQUIT
  cntrl +\ this causes a core dump and could be useful to handle for debugging, maybe by making sure the latest log is in a log.log file?
• SIGUSER!/SIGUSER2
  these can be used for custom actions , but this may be out of scope for our project

REMEMBER TO ADD TO READ ME
https://www.computerhope.com/unix/signals.htm

more indepth
https://www.man7.org/linux/man-pages/man7/signal.7.html

[ARaveala]

We have the choice of utilizing epoll_pwait() for signal handling however, there are certain signals that this would not catch like SIGTERM. We can catch the signals sent like SIGINT but then we must handle that inside the loop where epoll_pwait() is , this does allow us to handle gracefully. If the difference between managing signals ourselves or through epoll_pwait() is more or less gracefully is something that needs to be analyzed yet.