command line shown by ps

[Mark Towfiq]

In article <JOCKC.91Feb20103537 at hammer.idsila.com>
jockc at hammer.idsila.com (PRIV Account) writes:

   How can a process change or obscure the command line that
   ps (and other programs like w or whodo) show for it?  

   This could obviously be desirable for security reasons, but also for
   informational purposes.  For example, when a program forks a child
   process to do something, the child proc might want to change
   its "command line" (what ps shows, which by now probably has little
   meaning) to something more descriptive of what its doing.

Amazingly, the situation you describe and the reasons for it are
exactly the ones met by the setproctitle() call in sendmail.  When it
forks a child, the child describes its current status by munging its
argv array.  This does not work on all systems, as you suggest (such
as ones which malloc() argv entries and expect them not to be
clobbered) but most BSD-type systems can handle it.  Check out the
source for sendmail, obtainable from many many anonymous FTP hosts
(such as uunet.uu.net or ucbvax.berkeley.edu).

Hope this helps.
--
Mark Towfiq, FTP Software, Inc.                                  towfiq at FTP.COM
Work No.: +1 617 246 0900			      Home No.: +1 617 488 2818

  "The Earth is but One Country, and Mankind its Citizens" -- Baha'u'llah