topic Re: Detached process does not run, but no error indicated in Operating System - OpenVMS

Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 09:48:13 GMT

I am having a problem detached processes.

I have some processes that I used to run detached all the time. They don't run anymore and I don't know what has changed.

The program is normally launched from another program via SYS$CREPR. The call returns SS$_NORMAL, but no new process is created. Normally, the process runs continuously until it gets a command to exit. I determined that the first line of code in the program is never executed. If I run the program "un-detached" it runs fine. The same thing is observed if I run it detached from the DCL prompt. When running from the DCL prompt I get a message that the process was started with PID = XXX.

To simplify the experiment, I created a test program that simply writes a text string to a file and exits. Again, everything is fine running normally, but not detached.

I ran each of the programs with the /dump qualifier and then ran the dump analyzer. The dump file was not created.

I am running OpenVMS version 7.2-1. My account has IMPERSONATE privilege and Maxdetach = 0. I also tried setting Maxdetach to 2. Actually, the account I am using has all privileges authorized and granted by default.

Any ideas?

Thanks
John

Re: Detached process does not run, but no error indicated

Jan van den Ende — Tue, 18 Jan 2005 10:20:42 GMT

John,

first check:

DID the process even get created?

ACCOUNTNG is THE tool to find out!
And _IF_ it was, then the final status can give you vital info!

If not, one further question:
It used to function, you write.

Same VMS version, same user?
I am thinking various quota here, later VMS versions tend to require ever more, or a different user might have different quota, even the same user might have altered quota.

Just the first things to check, and on the answers, we can take it from there.

Proost.

Have one on me.

Jan

Re: Detached process does not run, but no error indicated

Bojan Nemec — Tue, 18 Jan 2005 10:30:32 GMT

John,

Try to set the PRC$M_IMGDMP flag in the stsflg (the last one, where you set the PRC$M_DETACH flag) of the SYS$CREPRC system service. You will receive a dump file (on yours current default directory, image name with the .DMP type). You can analize this dump, with:

$ ANALIZE/PROCESS dumpname

This command puts you in the debugger where you can inspect what hapens.

Bojan

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 10:46:43 GMT

Jan-

Thanks. I will try the ACCOUNTING utility. I'll let you know what I find out. I am not familiar with it, so it may take a while. In the meantime, the answers to your questions:

I am using the same version of OVMS as I did when it worked and the same user. I don't believe the user quotas have changed, but I tried all the tests with another user (that we never change) and got the same results.

Re: Detached process does not run, but no error indicated

Bojan Nemec — Tue, 18 Jan 2005 10:59:04 GMT

John,

Sorry, I forgot that you can force the dump (mentioned in my previous post) when you use the run command with the /DUMP qualifier:

$ RUN/DETACHED/DUMP ...

Bojan

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 11:03:17 GMT

Jan-

I ran accounting/user={username} and then ran the process detached from another window. The process never showed up.

Thanks

Re: Detached process does not run, but no error indicated

Lokesh_2 — Tue, 18 Jan 2005 11:04:30 GMT

Hi John,

Is your system sylogin.com (logical sys$sylogin) changed recently?

Something like the following is added:

if f$mode() .eqs. "OTHER" then logout

Thanks & regards,
Lokesh

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 11:04:58 GMT

Bojan-

I tried the /dump qualifier at the DCL prompt and no dump file was created.

Thanks

Re: Detached process does not run, but no error indicated

Bojan Nemec — Tue, 18 Jan 2005 11:16:31 GMT

John,

No dump file means that the program exited normaly. To get Jans accounting information try with this sequence:

$ T=F$TIME()
$ RUN/DETACHED ...
$ ACCOUNTING/USER=you/SINCE="''T'"/FULL

Bojan

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 11:24:49 GMT

Lokesh-

Actually it has changed. I placed the line

set term/perm/insert/vt100

in the MODE_OTHER section
I commented this out, logged off, logged on and re-ran the test. The same thing happened. The only other line in that section is

Exit 1

I'm not sure, but I don't think the exit command is the problem - I think that has always been there.

Thanks
John

Re: Detached process does not run, but no error indicated

Bojan Nemec — Tue, 18 Jan 2005 11:34:43 GMT

John,

You must avoid any terminal settings if you are not sure that you have a terminal attached to yours process.

Maybe you can try to debug the program (if you have the sources and posibility to compile the program with the debugger). Here is an Ask the wizard page which speaks about debugging deatached processes:

http://h71000.www7.hp.com/wizard/wiz_4640.html

Bojan

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 11:47:55 GMT

Bojan-

I placed that command there on accident and never removed it (I should have put it in the INTERACTIVE_MODE section). I decided to put the command into individual login.com files instead and never went back to clean it up.

Thanks
John

Re: Detached process does not run, but no error indicated

Dale A. Marcy — Tue, 18 Jan 2005 11:48:01 GMT

I have not seen the command that you are executing to create the detached process, but it might be worth looking at the protections on any input and/or output files specified to see if they have been changed.

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 11:59:16 GMT

Dale-

I created and ran a new test executable that simply writes a text string to a file then exits. If I run the test program normally, the file is created and contains the text string. If I run it detached, it does not. This test program should run detached, so I don't think I need to check input/output files of the other program. Also, I don't think there could be a security issue, since I can run either program normally and they function fine.

Thanks
John

Re: Detached process does not run, but no error indicated

Dale A. Marcy — Tue, 18 Jan 2005 12:04:17 GMT

That makes sense, but I saw where you said your account had all privileges by default and was not sure that was the same account you were using for the detached runs.

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 12:05:27 GMT

Bojan-

I'm going to try your procedure. One question, though, will the ACCOUNTING utility continue to append to a log file after I'm done testing? Or is there anything else I should be aware of?

Thanks
John

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 12:11:13 GMT

Bojan-

I ran your procedure and it just hangs after the accounting command. I believe this means that it didn't run. Is that true?

Thanks
John

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 12:13:07 GMT

Dale-

Yes, that was the account I was using.

Thanks
John

Re: Detached process does not run, but no error indicated

John Popernack — Tue, 18 Jan 2005 12:20:21 GMT

Bojan-

I went to the link you sent to me for debugging detached processes. I am unfamiliar with some of the steps in the process. Do you know of any examples of this that exist?

Thanks
John

Re: Detached process does not run, but no error indicated

Bojan Nemec — Tue, 18 Jan 2005 12:26:40 GMT

John,

The accounting utility is managed with the command SET ACCOUNTING. You can see which resources are tracked by the accounting with the SHOW ACCOUNTING command. The ACCOUNTING command runs a program which reads the accounting file (most times SYS$MANAGER:ACCOUNTNG.DAT or a file pointed by the logical name ACCOUNTNG).

Now, first check if you have enabled the process accounting, with the SHOW ACCOUNTING. You should see one of these lines:
PROCESS any process termination
DETACHED detached job termination

If accounting is not enabled for any of these resources, you can enable with:

$ SET ACCOUNTING/ENABLE=DETACHED

Then try to run the detached process.
Now you can try with the ACCOUNTING command. (you can use the /IDENT qualifier with the pid you receive from the RUN command or use my previous sequence of commands)

If you have enabled and want to disable accounting for detached processes use:
$ SET ACCOUNTING/DISABLE=DETACHED

Bojan