Sponsored Content
Top Forums UNIX for Dummies Questions & Answers How to wait for a grand child to finish? Post 302928909 by sai2krishna on Tuesday 16th of December 2014 06:17:58 AM
Old 12-16-2014
Ubuntu How to wait for a grand child to finish?

Hello all,

I have a very basic question. I have a requirement where in, I have a main process which forks a child process, which execs and runs a c executable corresponding to a daemon. In the c executable corresponding to a daemon, as everyone does, I fork another child process, and as part of child, run the daemon functionality by its parent exiting, so that the child(daemon) becomes a child of init. Now, from the main process(grand parent), I would like to wait for the daemon process(grand child).

Just to explain more clearly, I have a process p1, which forks a new process p2. In p2 functionality, I fork another process p3 which execs and runs a daemon, p2 exits to make p3 a child of init. Now, from p1, I want to wait for p3. I can not use waitpid in the grand parent process to wait for the grand child I believe. How to proceed?

I would be very glad if you can help me.

Thanks in advance,
Sai
 

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

How can I wait for PID to finish in another shell

Have a need to schedule programs that can run after other programs are completed. Here's the catch: 1) The list of programs will not always be the same (kind of a plug-n-play deal) 2) The invoking shell may not be the same as the shell of the program being waited on In other words, I need... (2 Replies)
Discussion started by: superdelic
2 Replies

2. Programming

Howto spawn multiple child processes and wait?

As far as I can tell, the bash wait command waits for a logical "AND" of all the child processes. Assuming I am coding in C: (1) What is the function I would use to create multiple bash child process running perl? (2) What is the function I would use to reinvent the bash wait command so I... (4 Replies)
Discussion started by: siegfried
4 Replies

3. Shell Programming and Scripting

How to wait for the subprocess to finish in tcl

Hi All Here i have a piece of code, set filename "./GopiRun.sh" #I need to wait here until the GopiRun.sh is completed how do i achive this exit. (1 Reply)
Discussion started by: nathgopi214
1 Replies

4. UNIX for Advanced & Expert Users

how to make a parent wait on a child shells running in background?

Hi I have a shell script A which calls another 10 shell scripts which run in background. How do i make the parent script wait for the child scripts complete, or in other words, i must be able to do a grep of parent script to find out if the child scripts are still running. My Code: ... (1 Reply)
Discussion started by: albertashish
1 Replies

5. Shell Programming and Scripting

Make cron wait for the child process

I am trying to find a list of files and writing it to a text file. Based on the machine performance the file writing will be slow at certain time. The code to find file and redirecting the output to text file is on a shell script /usr/bin/find $SEARCH_DIR -daystart \( \( -name 'KI*' -a... (4 Replies)
Discussion started by: nuthalapati
4 Replies

6. Programming

Parent,child wait,signal

Hello. I want to make a child do some stuff,wait,then the parent does some stuff and then child does some stuff and waits again.I have made the following but it does not work.Can anybody help me? pid1 = fork(); if (pid1 == -1) { perror("Can't create child\n"); ... (18 Replies)
Discussion started by: Cuervo
18 Replies

7. Shell Programming and Scripting

How to WAIT for jobs in each group to finish?

I have the shell script to call a Perl routine and pass the Informatica WorkFlow name to it. Jobs in each group executes in background do not seem to wait at all. How do I make it to WAIT for the prior group to complete before execute the next group of jobs? Sample of the jobs flow: { ... (6 Replies)
Discussion started by: lv99
6 Replies

8. Shell Programming and Scripting

How to wait for tar to finish before sending the archive through ftp?

Hey all, I want to automate tarring a directory then using ftp to transfer the files over. I was able to put the commands together but what I'm noticing is that only the very first file is being tarred and then transferred. tar cvpf new.backup sourceAbove is the command I'm using which works... (4 Replies)
Discussion started by: Keepcase
4 Replies

9. Shell Programming and Scripting

How make parent to wait from child process?

Hi all, I am starting mgen5 for sometime depends on input from a file, in a child process. now I want to make parent to wait in this child process till mgen5 finishes, or timeout happens. could anyone please tell me how to make parent to wait in child process in shell script? thanks... (2 Replies)
Discussion started by: girijajoshi
2 Replies

10. UNIX for Beginners Questions & Answers

Wait till any one child process finishes

Hi I am facing a problem in my ksh. My main script is calling 3 different child process in the background. I am using wait to finish all and then submit another 3 child processes. Now what i want is , whenever any one child process finishes ,i want to submit next one.so that parallel 3... (2 Replies)
Discussion started by: Sangu
2 Replies
preap(1)                                                           User Commands                                                          preap(1)

NAME
preap - force a defunct process to be reaped by its parent SYNOPSIS
preap [-F] pid... DESCRIPTION
A defunct (or zombie) process is one whose exit status has yet to be reaped by its parent. The exit status is reaped via the wait(3C), waitid(2), or waitpid(3C) system call. In the normal course of system operation, zombies may occur, but are typically short-lived. This may happen if a parent exits without having reaped the exit status of some or all of its children. In that case, those children are reparented to PID 1. See init(1M), which periodically reaps such processes. An irresponsible parent process may not exit for a very long time and thus leave zombies on the system. Since the operating system destroys nearly all components of a process before it becomes defunct, such defunct processes do not normally impact system operation. However, they do consume a small amount of system memory. preap forces the parent of the process specified by pid to waitid(3C) for pid, if pid represents a defunct process. preap will attempt to prevent the administrator from unwisely reaping a child process which might soon be reaped by the parent, if: o The process is a child of init(1M). o The parent process is stopped and might wait on the child when it is again allowed to run. o The process has been defunct for less than one minute. OPTIONS
The following option is supported: -F Forces the parent to reap the child, overriding safety checks. OPERANDS
The following operand is supported: pid Process ID list. EXIT STATUS
The following exit values are returned by preap, which prints the exit status of each target process reaped: 0 Successfully operation. non-zero Failure, such as no such process, permission denied, or invalid option. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWesu (32-bit) | +-----------------------------+-----------------------------+ | |SUNWesxu (64-bit) | +-----------------------------+-----------------------------+ SEE ALSO
proc(1), init(1M), waitid(2), wait(3C), waitpid(3C), proc(4), attributes(5) WARNINGS
preap should be applied sparingly and only in situations in which the administrator or developer has confirmed that defunct processes will not be reaped by the parent process. Otherwise, applying preap may damage the parent process in unpredictable ways. SunOS 5.10 26 Mar 2001 preap(1)
All times are GMT -4. The time now is 09:07 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy