Solved

How to Clean up an Orphan Process in HP-UX?

Posted on 1997-06-03
6
651 Views
Last Modified: 2013-12-06
Suppose we have a process, and it forks a child process, in HP-UX 10.0.  If the parent terminates (in an unexpected way), we may want to let that orphan child process exit.  How can this be implemented?  Or in other words, how can the child process know its parent has terminated?  (It seems signal SIGHUP doesn't work, and the system doesn't clean up it in a short time.)
0
Comment
Question by:cheng060397
  • 3
  • 3
6 Comments
 

Expert Comment

by:beckers012097
ID: 2006352
Where are you trying to handle the SIGHUP in parent- or child-process? Normally the signal-handling in HP-UX is very clean an works fine...
0
 

Author Comment

by:cheng060397
ID: 2006353
Thanks, Beckers!  What I understand is that SIGHUP is generated when parent process terminates.  So I let child handle it, but it turned out that the child couldn't receive that signal.  (If the child called kill(getpid(), SIGTSTP) to suspend itself, it would receive it. (See Stevens' book, pages 256-258.)  But no one wants to suspend the child.)  My code looks like:
   
void main()
{
    childpid = fork();    
    if (childpid == -1) {
      perror("fork error\n");
      exit(0);
    }
    else if(childpid == 0) {                   /* child */      
        signal(SIGHUP, sig_func);
        /* some child code here */
    }                                           
    else {                                 /* parent */
        /* some parent code here */
    }
}

void sig_func()                             /* signal handler */
{
    printf("SIGHUP received.\n");
    exit(1);
}

0
 

Accepted Solution

by:
beckers012097 earned 100 total points
ID: 2006354
Try using a signal-handler in parent-process (for all fatal signals like SIGKILL, SIGSEV etc.). In this signal handler shut down the child-process (you know the pid from fork) by sending a "soft"-kill. Then after recieving the childs exit-status terminate the parent-process.

But I don't understand the reason for not getting SIGHUP...
0
Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 

Author Comment

by:cheng060397
ID: 2006355
Thanks, beckers, but I am not sure those fatal signals can cover all unexpected terminations.
0
 

Expert Comment

by:beckers012097
ID: 2006356
They should, there are no other reasons for terminating a program than the signals you can catch. Or I understood it wrong for 10 years... Catch all signals?!?
0
 

Author Comment

by:cheng060397
ID: 2006357
Thanks, beckers!

0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Java performance on Solaris - Managing CPUs There are various resource controls in operating system which directly/indirectly influence the performance of application. one of the most important resource controls is "CPU".   In a multithreaded…
Every server (virtual or physical) needs a console: and the console can be provided through hardware directly connected, software for remote connections, local connections, through a KVM, etc. This document explains the different types of consol…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
This video shows how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.

827 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question