How can I tell in Linux which process sent my process a signal

Question

I have a java application that got SIG TERM. I want to know the pid of the process that sent this signal.
Is that possible?

Answer 1

No, Signals are not intended as an interprocess communication channel. As far as I am aware, there is no PID passed. The sending PID is irrelevant for all of the uses I have seen for signals. You can be relatively sure that the processes sending the signal either had root privileges, or belonged to the same UID as your process.

It is possible that the process that sent the signal does not exist anymore. If the kill command was used rather than the shell built-in, it is almost certain the process no longer exists.

From the Java side this is even more difficult. The process runs in a Java Virtual Machine, which is abstracted from the Operating System. Not all Operating System concepts exist with this machine.