UNIX per-process accounting

[Barry Shein]

To summarize, Fred Toth is looking for a way to charge work to
customers using a SUN3 in a manner similar to that provided through
kernel mods in previous systems. The hook seems to be that when work
is done for a customer it is done in a particular directory.

I've got it (I think):

Assuming you can/will set the group of the directory to something
indicative of which customer is involved (say, their name), you could
create a .cshrc alias for 'cd' which will grovel out the group name
(this could be done most easily by writing a little C program which
just does a stat on the target, looks up the group name and prints it
to the standard output so it can be used in a backquote arg, or you
can grovel a 'ls -ldg' with sed or awk.) Then, write a null program
with the same name as the group, this is run on each 'cd' simply to
leave it's accounting stamp in the accounting file. Then, when you
run through the accounting files you have windows between the running
of each group name to charge. done.

Ok, that's pretty obscure, so here's some code:

let us say that directory xyzzy has group ownership Joe, that a
program 'pgroup' is written which simply prints out the group field
to the standard output and there exists a program 'Joe' which does
nothing but just run (main(){ exit(0);}). An alias might be:

	alias CD '`pgroup \!^`;cd \!^'

Now if you do a lastcomm after running that program it should reveal
that your user just ran a program named Joe, thus you know to start
charging all subsequent jobs to the account 'Joe'. When he cd's somewhere
else, a new group will be stamped in the accounting file (or, s/he can
use good ole 'cd' rather than 'CD' if that's not his/her intention.)
(That is, 'CD xyzzy' expands to '`pgroup xyzzy`;cd xyzzy' which expands
to 'Joe;cd xyzzy'. I tried an example, it should work.)

Done. (I think.) No kernel hacks, 10 minutes work. I suppose some sort
of pushdown approach could be done, but that's left as an exercise for
the reader :-) If that's not clear ask, but ask fast, I'm gonna forget
this one real fast I think. Also, give a thought to security.

	-Barry Shein, Boston University