brent@capmkt.COM (Brent Chapman) (07/20/89)
I think that using SIGHUP to trigger dumps is a bad idea. SIGHUP is
what gets sent to programs by the operating system on a "hangup"
condition, which happen fairly often, and generally causes the program
to exit (perhaps after doing some cleanup and shutdown work).
If someone closes a window or is dialed in and disconnects (or gets
disconnected) without first terminating any running programs, those
programs are sent a SIGHUP. Normally, the program simply exits, and
everything is cool. ISIS programs, however, catch SIGHUP and interpret
it to mean "do a dump, then continue"; thus, ISIS programs are left
running, chewing up resources (CPU, ptys if the program was running in a
window, modems if the program was running on a dialup line, etc.) until
someone (the person who ran it in the first place, or root) comes along
and explicitly kills the program. I think this is bad; I (and most
other system administrators) have better things to do than go around
looking for these "orphan" programs to be killed.
In my opinion, SIGHUP should cause ISIS programs to exit, just like all
other programs; the dump signal should be something else, like SIGUSR1.
-Brent
--
Brent Chapman Capital Market Technology, Inc.
Computer Operations Manager 1995 University Ave., Suite 390
brent@capmkt.com Berkeley, CA 94704
{apple,lll-tis,uunet}!capmkt!brent Phone: 415/540-6400ken@gvax.cs.cornell.edu (Ken Birman) (07/20/89)
I don't have any problems with changing to SIGUSR1. We are about to put a new copy of the beta release out on the network. I'll include this change at the same time. Sorry that the V1.2 release seems to be advancing slowly. I'm running a 10-day course here in Ithaca (Fingerlakes 89) and it hasn't left me with much time to work on the system. Ken