2.4.20: problem with "ps -olstart"

[Eyal Lebedinsky]

I have a program that needs to check if a process is still running.
It issues a ps and saves the pid and start time. It then uses this
info to compare against a later "ps --pid".

The monitored process is long-running and unlikely to restart at the
same second and with the same pid. I am trying to go better than
just using a pid sentry (I also compare the cmd to be really sure).

I see a different start time returned on different calls. An example
is attached below. This is a show stopper for me. Is this a known
problem? Does it have a solution?

This is vanilla (my build) 2.4.20 on i386.

$ ps
  PID TTY          TIME CMD
  906 pts/0    00:00:01 bash
 3026 pts/0    00:00:00 sh
 8254 pts/0    00:00:00 ps
$ while true ; do ps --pid "3026" -olstart,cmd --no-headers ; done
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:11 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:12 2003 sh
Thu Mar 27 22:03:11 2003 sh

--
Eyal Lebedinsky ([e-mail]) <http://samba.org/eyal/>