topic Re: daemon process in Operating System - HP-UX

daemon process

Vineet Goel_1 — Thu, 08 Apr 2010 19:37:14 GMT

Hello All,
I have a daemon process, which is aborting. It does not create core file. This process is not loggin much of the log process.
I want to debugg with out modifying source code.
Is there any way I can get the error message this daemon process thowing on STDERR.
I tried playing around with file descriptor but it did not work.
I redirect 1>& and 2>& and then start the process but nothing is logged into file.
I tried something like
3<>File # open a file with FD 3
3<&2 # assign STDERR to 3
3<&1 # assign STDIN to 3
but nothing is working out

Can somebody advise if it is possible to get error message from a daemon process.

Thanks,
Vineet.

Re: daemon process

Patrick Wallek — Thu, 08 Apr 2010 19:46:32 GMT

You should be doing the redirect on the command line that starts the process.

Something like:

# startprocess > /var/tmp/errorfile 2>&1

Re: daemon process

Dennis Handly — Fri, 09 Apr 2010 06:18:19 GMT

Some demons go out of their way to close stdout and stderr and reopen /dev/null. Do you do that?

You might be able to do:
startprocess 3> /var/tmp/errorfile

Then attach with gdb before the error and:
p close(2)
p dup(3)

Re: daemon process

Vineet Goel_1 — Fri, 09 Apr 2010 12:14:59 GMT

Thank you,
Vineet.