Login or Register to Ask a Question and Join Our Community


UNIX for Advanced & Expert Users

How to check a single process instance is always running?

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums UNIX for Advanced & Expert Users How to check a single process instance is always running?
# 1  
Old 05-13-2014
Linux How to check a single process instance is always running?
Hi,
I want to write one program in C in Unix OS which will check the running status of a process time to time. If the process is stopped somehow by any means, it will ensure that the process is restarted and only one copy of the process image should run in memory at any point of time for the user.

I am not bothering about whether the processes are related or not.

How can I write this code in C?

Is there any inter process communication mechanism required to achieve this?

Thanks in advance for your suggestions.

--sanzee
# 2  
Old 05-13-2014
The "record - locking" concept ensures, one copy of process is running. If each daemon creates a file and places a write lock on the entire file, only one such write lock will be allowed to be created. Successive attempts to create write locks will fail.
# 3  
Old 05-13-2014
This is what daemons use PID files for.

When a daemon is launched, it creates a file, typically under /var/run/, containing its own process ID. When it quits, it deletes this file.

External things can check whether /var/run/mydaemon
1) exists
2) refers to a PID that already exists

If both these conditions are true, the process exists. Otherwise it should be restarted.
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Check if process is running if not then use command

Hello, Could someone do the following bash ubuntu script for me? I have 5 screen processes of bot: SCREEN -dmS Xbot_instance_1 php core.php -i 1 SCREEN -dmS Xbot_instance_2 php core.php -i 2 SCREEN -dmS Xbot_instance_3 php core.php -i 3 SCREEN -dmS Xbot_instance_4 php core.php -i 4 ... (2 Replies)
Discussion started by: kotch
2 Replies

2. Shell Programming and Scripting

Process Instance not running properly.

I have run 10 instances of the process eg, process name is BG nohup /WP01IRB1_irbapp/IRBWPROD/RB/bin/BG -c 1 -t 23 -a '-caTop TESTBILLCYCLE='5FEB13_81PT19NPT''>a.txt & nohup /WP01IRB1_irbapp/IRBWPROD/RB/bin/BG -c 2 -t 23 -a '-caTop TESTBILLCYCLE='5FEB13_81PT19NPT''>b.txt & nohup... (3 Replies)
Discussion started by: ankitknit
3 Replies

3. UNIX for Dummies Questions & Answers

How a process can check if a particular process is running on different machine?

I have process1 running on one machine and generating some log file. Now another process which can be launched on any machine wants to know if process1 is running or not and also in case it is running it wants to stream the logs file generated by process1 on terminal from which process2 is... (2 Replies)
Discussion started by: saurabhnsit2001
2 Replies

4. Shell Programming and Scripting

need to check if the process is running

Hi, I check if the process is running or not using the below. /usr/ucb/ps auxww | grep 109 |grep rmi | awk '{print $2}' 9718 Thus we see 9718 is the PID. It return blank if the process is not running. I need to perform some action if the process is not running and leave it if... (8 Replies)
Discussion started by: shifahim
8 Replies

5. Programming

How do I check if a process is running in C

How to I check if a process is running in C? I'm trying to use ps aux |grep "process name" but failing in doing that. How do I do that? Thanks, (1 Reply)
Discussion started by: cprogdude
1 Replies

6. UNIX and Linux Applications

How to check if process is running?

Hi I would like to check if an instance of a script is already running. I've seen many different examples, but I haven't the slightest idea as to how to do this. Can you please help. Thank you. (5 Replies)
Discussion started by: ladyAnne
5 Replies

7. Shell Programming and Scripting

Check if Process is running

Hi , I have a csh code below which check the process if it's running. Can any expert advise me on the following: 1) what does this notationmean ">!" and how is it different from the append ">" notation ? 2) how does "setenv" work in this code ? # Check whether there is a running... (3 Replies)
Discussion started by: Raynon
3 Replies

8. UNIX for Advanced & Expert Users

how to check how long the process has been running.

I have a requirement to check how long a process is running on unix system.If i use ps -ef i am getting the following message guest 2453638 1998920 0 16:16:05 - 0:00 dsapi_slave 9 8 0 but this is showing only time not the date.Can any one please advice me any script to find out how... (2 Replies)
Discussion started by: ukatru
2 Replies

9. Shell Programming and Scripting

check process running

I have this script: ------------------------------------------------------- #!/bin/ksh # if ] || ] then echo "Executing main_load.sh script" /usr1/psc_load/jobs/cron/main_load.sh "ods" else echo "File not found, do nothing" fi exit 0 ... (4 Replies)
Discussion started by: rose1207
4 Replies

10. Shell Programming and Scripting

How to check if another instance of the process is running

Hi, I am writing a shell script to invoke a C++ program. Before I start the C++ program (oi7loadbalancer), I am checking if the process is already running. I start the process only if it is not already running. I have the following check in my script. proccount=`ps -f -u $USER_NAME | grep... (8 Replies)
Discussion started by: sim
8 Replies
Login or Register to Ask a Question