Re: libgcj/7532: shutdown hooks not run upon abnormal termination

[Andrew Haley <aph@cambridge.redhat.com>]

The following reply was made to PR libgcj/7532; it has been noted by GNATS.

From: Andrew Haley <aph@cambridge.redhat.com>
To: tromey@redhat.com
Cc: <jmr@fulcrummicro.com>, gcc-gnats@gcc.gnu.org
Subject: Re: libgcj/7532: shutdown hooks not run upon abnormal termination
Date: Mon, 19 Aug 2002 10:08:29 +0100 (BST)

 Tom Tromey writes:
  > jmr> 	Shutdown hooks added with Runtime.addShutdownHook() are not run
  > jmr>         if the program terminates abnormally, ie due to Ctrl-C.
  > 
  > Yeah, definitely a bug.
  > 
  > jmr> Here's a patch that installs a signal handler to catch SIGHUP, SIGINT, and
  > jmr> SIGTERM.  The handler calls System.exit() so the shutdown hooks run.
  > jmr> Installation of the signal handlers can be disabled with
  > jmr> --reduce-signal-usage.
  > 
  > I don't think we can do this stuff directly from the signal handler.
  > I'm not sure what a better approach is though.  Maybe Andrew has an idea.
 
 I think it's legal to do this from a signal handler.  However, we
 might deadlock if a thread is inside a synchronized region at the time
 the ctrl-C is caught.  We could perhaps solve this by sending a
 message to a dedicated shutdown thread instead of quitting immediately
 but I don't know if the extra complexity can be justified.
 
 However, we must ensure that if a second ctrl-C is received we
 terminate immediately.
 
  > I also don't think we need a gij command-line argument to reduce
  > signal usage.
 
 I agree.
 
 Andrew.