Saturday, April 13, 2013

Signal Handling

Ignore

No action is taken.  Two signals cannot be ignored - SIGKILL and SIGSTOP to allow SA to be able to kill or stop all processes.  Otherwise, there will be processes that is unstoppable.

Catch and handle

The kernel suspend the execution of the process's current code path and jump to the signal handler registered.  Execution will continue once the handler ends.  SIGINT and SIGTERM are 2 commonly caught signal.  SIGINT allows the shell process to return to the prompt.  SIGTERM allow the process to clean up for a orderly terminating.

Perform default action

Take the defaul action usually means terminating the process

No comments: