Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!uunet!mcvax!kth!sunic!dkuug!freja!seindal
From: brent@capmkt.COM (Brent Chapman)
Newsgroups: comp.sys.isis
Subject: ISIS using SIGHUP to trigger dumps considered harmful
Message-ID: <4669@freja.diku.dk>
Date: 20 Jul 89 00:42:27 GMT
Sender: seindal@freja.diku.dk
Lines: 28

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:  415/540-6400