Finding the process which sent signal in c

Question

I have a child process which might receive sigterm signal from its parent or from somewhere else. I have to take appropriate action if the signal is from parent. How can i find if the received signal is from parent in c(linux)?

Answer 1

You set up your signal handler with sigaction using the SA_SIGINFO flag. Your handler will accept a parameter of siginfo_t . Within the siginfo_t struct is the field si_pid . This is the process id of the sending process. Match that against the child's ppid().