Path: utzoo!attcan!uunet!samsung!usc!zaphod.mps.ohio-state.edu!mips!prls!pyramid!unify!rja
From: rja@unify.uucp (Rick Anderson)
Newsgroups: comp.databases
Subject: Re: Hang-up signals in Informix 4gl
Message-ID: <13v6kp3@unify.uucp>
Date: 13 Apr 90 02:42:22 GMT
References: <2536@husc6.harvard.edu>
Reply-To: rja@unify.UUCP (Rick Anderson)
Organization: Unify Corporation, Sacramento, CA, USA
Lines: 30

In article <2536@husc6.harvard.edu> bochner@harvard.EDU (Harry Bochner) writes:
>I've been having the following problem with INFORMIX-4gl RDS (2.10.03F
>on a sun4):
>Our users use rlogin from (Encore) annex boxes. From time to time a user is
>forceably logged out, for instance because of a failure in the annex
>box. The host
>machine gets a hangup signal, which properly kills the login shell, but it
>doesn't kill the user's 4gl processes: instead of dying, fglgo falls
>into a tight
>loop (probably trying to report the error?), and eats up all the CPU
>time it can
>grab. These runaway jobs keep running, and degrading system performance, until
>they are killed manually (or the system crashes).
>
>[deleted...]

Some of our customers have experienced similar events on other platforms,
almost universally all of them running through annex boxes or other
multiplexing-type exchanges.  The problem has been identified (in our case,
anyways) as the UNIX 'read(2)' function being interrupted (SIGHUP) but
returning a value of "0" instead of a value of '-1' and "errno=EINTR".
On some platforms, we have been told that we should check 'errno' whenever
a return value of "0" or "-1" is returned from 'read(2)'.



-- 
Richard J. Anderson		                       internet: rja@unify.UUCP
Unify Corporation		                 ...!{csusac,pyramid}!unify!rja
3870 Rosin Court                                          voice: (916) 920-9092 Sacramento, CA 95834                                        fax: (916) 921-5340