Hi Roger,
Sorry I couldn't look into the code in extreme detail right now but
would like to clarify the big picture ...
Can you please clarify the exact flow of control from when a signal is
sent to the process and when the Java handler for it gets to run - what
is handled by which thread where, and in what context (signal handling
context or regular execution context)? I'm assuming no Java code is ever
being executed in a signal handling context, but I'm not clear on the
threading model being used here.
Is the VM still responsible for the initial receipt of all signals?
Howe do you manage a user-defined signal handler, for ctrl-C say, with
the default behaviour for that signal (orderly shutdown) ?
Thanks,
David
On 2/02/2016 2:02 AM, Roger Riggs wrote:
Please review an API addition to handle signals such as SIGINT, SIGHUP,
and SIGTERM.
This JEP 260 motivated alternative to sun.misc.Signal supports the use
case for
interactive applications that need to handle Control-C and other signals.
The new java.util.Signal class provides a settable primary signal
handler and a default
signal handler. The primary signal handler can be unregistered and
handling is restored
to the default signal handler. System initialization registers default
signal handlers
to terminate on SIGINT, SIGHUP, and SIGTERM. Use of the Signal API
requires
a permission if a SecurityManager is set.
The sun.misc.Signal implementation is modified to be layered on a common
thread and dispatch mechanism. The VM handling of native signals is not
affected.
The command option to reduce signal use by the runtime with -Xrs is
unmodified.
The changes to hotspot are minimal to rename the hardcoded callback to
the Java
Signal dispatcher.
Please review and comment on the API and implementation.
javadoc:
http://cr.openjdk.java.net/~rriggs/signal-doc/
Webrev:
jdk: http://cr.openjdk.java.net/~rriggs/webrev-signal-8087286/
hotspot: http://cr.openjdk.java.net/~rriggs/webrev-hs-signal-8087286/
Issue:
https://bugs.openjdk.java.net/browse/JDK-8087286
JEP 260:
https://bugs.openjdk.java.net/browse/JDK-8132928
Thanks, Roger
