Experimental Physics and
Industrial Control System

Hi Ralph,

 

I have run into what seems to me a bug in procServ 2.6.0 when running on RHEL6/Centos6.  The problem occurs when trying to start another procServ process using the same telnet port as an existing procServ process.

 

This is what I observe when running on Fedora 15 (Linux version 2.6.43.8-1) or on Centos7 (Linux version 3.10.0-229)

 

[det@ppu071 linux-x86_64]$ /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

/usr/local/bin/procServ: spawning daemon process: 41899

 

[det@ppu071 linux-x86_64]$ /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

Caught an exception creating the initial control telnet port: Address already in use

/usr/local/bin/procServ: Exiting with error code: 98

 

I think this is the correct behavior. procServ should exit with an error if the telnet port is already in use.  This is a protection against accidentally starting the same procServ process twice.

 

However, on Centos6/RHEL6 (Linux version 2.6.32-431) I observe the following:

 

det@dec1248:~> /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

/usr/local/bin/procServ: spawning daemon process: 60423

 

det@dec1248:~> /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

/usr/local/bin/procServ: spawning daemon process: 60555

 

det@dec1248:~> /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

/usr/local/bin/procServ: spawning daemon process: 60610

 

So procServ happily creates multiple procServ processes listening on the same telnet port.  These are all running:

 

det@dec1248:~> ps ax | grep procServ

60423 ?        Ss     0:00 /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

60555 ?        Ss     0:00 /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

60610 ?        Ss     0:00 /usr/local/bin/procServ -L /home/det/test.log 30000 /bin/bash

 

This seems like a bug to me?  It is definitely inconvenient because if someone accidentally types the command to start a particular procServ without realizing that it is already running it can cause problems.

 

Is there something I can do to work around this issue?

 

Thanks,

Mark