[comp.unix.questions] /etc/ps_data

BKEHOE%WIDENER.BITNET@cornellc.cit.cornell.edu (07/04/90)

 Just curious..
 Whenever they reboot the 3b2/400 here, any attempt to do /etc/whodo or ps
results in '/etc/ps_data: file does not exist' (which, after rtfm'ing, I
found out was the internal data structure file used by ps, whodo, et al);
my question is, what is it about rebooting that wipes this file out? To fix
this can ya simply touch the file so that something exists again? How is it
recreated?

Thanks..
--
Brendan Kehoe (bkehoe@widener.bitnet) -- Sun Systems Manager

cpcahil@virtech.uucp (Conor P. Cahill) (07/04/90)

In article <23795@adm.BRL.MIL> BKEHOE%WIDENER.BITNET@cornellc.cit.cornell.edu writes:
> Whenever they reboot the 3b2/400 here, any attempt to do /etc/whodo or ps
>results in '/etc/ps_data: file does not exist' (which, after rtfm'ing, I
>found out was the internal data structure file used by ps, whodo, et al);
>my question is, what is it about rebooting that wipes this file out? To fix
>this can ya simply touch the file so that something exists again? How is it
>recreated?

As a minimum, the ps command will re-create the /etc/ps_data file IFF the
/etc directory and the /bin/ps command are set up with the correct 
permissions.  I'm not sure if whodo will actually re-build the file, or 
just relies on ps to do it.

Anyway, 

	/bin/ps and /etc should look as follows:

-r-xr-sr-x   1 root     sys        21900 Mar 28 14:19 /bin/ps
drwxrwxr-x  20 root     sys         4256 Jul  3 15:01 /etc


Note that /etc is group writable, /bin/ps is setgid and the two
of them are in the same group.


-- 
Conor P. Cahill            (703)430-9247        Virtual Technologies, Inc.,
uunet!virtech!cpcahil                           46030 Manekin Plaza, Suite 160
                                                Sterling, VA 22170 

gwyn@smoke.BRL.MIL (Doug Gwyn) (07/04/90)

In article <23795@adm.BRL.MIL> BKEHOE%WIDENER.BITNET@cornellc.cit.cornell.edu writes:
> Whenever they reboot the 3b2/400 here, any attempt to do /etc/whodo or ps
>results in '/etc/ps_data: file does not exist' (which, after rtfm'ing, I
>found out was the internal data structure file used by ps, whodo, et al);

The way this was supposed to work is that "ps" is installed with sufficient
privilege to read /dev/kmem and also create /etc/ps_data, and the first
time "ps" is invoked it creates the database.