From owner-cvs-all  Sat Apr  7  5:15:35 2001
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Date: Sat, 7 Apr 2001 22:13:25 +1000 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: Dima Dorfman <dima@unixfreak.org>
Cc: Brian Somers <brian@FreeBSD.org>, cvs-committers@FreeBSD.org,
	cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/bin/ps ps.c 
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On Sat, 7 Apr 2001, Dima Dorfman wrote:

> Bruce Evans <bde@zeta.org.au> writes:
> > This stomps on PR 26057, which contains more complete fixes.  It's
> > not clear whether the bug is the non-removal of the sess column and
> > the sess keyword or the removal of the e_sess pointer.
> 
> This particular commit doesn't really hurt anything.  We just need to
> decide whether there should be an e_sess (or ki_sess, now) pointer or
> not.  PR 26057, which you mention, contains a patch to add it back.
> Although mckusick did explicitly say he was removing it in his
> kproc_info commit, he didn't provide rationale.
> 
> So, the question is: do we want a `sess' column?

Maybe not by default, but I think we want it.  Linux ps (at least
according to a RedHat ps.1 dated 1996/12/19) has a "session ID" (with
short keyword "o" and long keyword "session").  It doesn't seem to
anything corresponding to "tsess".  I think BSD ps was just abusing
the session pointers as unique IDs.  The terminal session pointer is
also printed by pstat(8).  It works there because it is read out of
a tty struct.

Larger pointers makes abusing pointers for IDs more of a hack than
before.  pstat(8) simply converts them to u_longs and prints them
using %8lx format (%p format is no good since it is uncontrollable).
On alphas, the values take more like 16 characters than 8 to print
and the formatting is messed up.  ps(1) is more careful.  It prints
only the trailing v->width characters.  The width was 6 for sess and
tsess.  Now it only prints 2 pointers (the ones for "nwchan" and
"paddr").  It uses width 6 for these too.  This makes the values shown
by ps for pointers almost useless for locating the pointers in kmem
and not even necessarily unique as IDs either -- even on i386's kernel
addresses are no longer unique in the last 6 nybbles.

Bruce


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