How to know if a process had been started but cras

Question

Consider the following situation: - I am using Linux. I have doubt that my application has crashed. I had not enabled core dump. There is no information in the log.

How can I be sure that, after the system restart my app was started, but now it is not running, because it has crashed.

My app is configured as a service, written in C/C++.

In a way: how can I get all the process/service names that have executed since the system start? Is it even possible?

I know, I can enable logging and start the process again to get the crash.

Answer 1

Daemons should always: 1) Write the currently running instance's process to /var/run/$NAME.pid using getpid() (man getpid) or an equivalent command for your language. 2) Write a standard logfile to /var/log/$NAME.log (larger logfiles should be broken up into .0.log for currently running logs along with .X.log.gz for other logs, where X is a number with lower being more recent) 3) /Should/ have an LSB compatible run script accepting at least the start stop status and restart flags. Status could be used to check whether the daemon is running.

Answer 2

As JimB mentions, you have the daemon write a PID file. You can tell if it's running or not by sending it a signal 0, via either the kill(2) system call or the kill(1) program. The return status will tell you whether or not the process with that PID exists.