review request: 4244896: (process) Provide System.getPid(), System.killProcess(String pid) (original) (raw)

Jason Mehrens jason_mehrens at hotmail.com
Wed Apr 18 13:44:12 UTC 2012

Rob,

It looks like waitFor is calling Object.wait(long) without owning this objects monitor. If I pass Long.MAX_VALUE to waitFor, shouldn't waitFor return if the early if the process ends?

Jason

Date: Tue, 17 Apr 2012 15:56:30 +0100 From: rob.mckenna at oracle.com To: Alan.Bateman at oracle.com Subject: Re: review request: 4244896: (process) Provide System.getPid(), System.killProcess(String pid) CC: core-libs-dev at openjdk.java.net

New webrev at: http://cr.openjdk.java.net/~robm/4244896/webrev.01/ Differences: - implemented Process.waitFor(long timeout). I figured I'd throw it in and let you decide if you want to keep it / replace isAlive. - implemented defaults in Process.java - destroyForcibly now returns the Process object - Updated documentation - Added @Override to all new overrides. - Fixed long line in UNIXProcessmd.c consistent with other functions in that file. - Replaced WaitForSingleObject with GetExitCodeProcess: given the concerns raised it seems to make more sense to leave users who return STILLACTIVE as an error code on their own. - Test updated to allow for proper execution of shell script. -Rob On 12/04/12 10:05, Alan Bateman wrote: > On 12/04/2012 00:48, Rob McKenna wrote: >> Hi folks, >> >> I'm hoping for some feedback on the above. Webrev: >> >> http://cr.openjdk.java.net/~robm/4244896/webrev.00/ > Thanks for taking this one on, a destroyForcibly is really useful to > have (destroy was always misleading given that that is was actually a > SIGTERM). The isAlive is also useful, another choice would be a > waitFor that takes a timeout. > > As this patch adds two abstract methods it means there will be a > source compatibility issue. Process has been in the platform since > JDK1.0 so it likely there are other implementation, perhaps mocked. > For destroyForcibly then a reasonable default could invoke the > existing destroy but this would need to be specified. A possible > default for isAlive is to invoke exitValue and mask the IAE when it > hasn't terminated. > > On the javadoc then destroyForcibly needs to specify the return value, > I think I missed this in the original patch that I gave you off-list. > Having it return the Process is very useful as it allows for method > invocation chaining, exitCode = p.destroyForcibly().waitFor(). I also > think destroyForcibly needs to set expectation that the process may > not terminate immediately (isAlive might still return true for a brief > period for example). > > The duplicate code in UNIXProcess.java.* is a reminder that we could > combine the common code into something like a private package > AbstractUNIXPorcess that would be extended by UNIXProcess, not for > this patch of course. > > Looks like there is inconsistent use of @Override, you've added it to > the isAlive implementation but not the others. > > Looks like UNIXProcessmd.c is straying beyond 80c so you might want > to move the force parameter to the next line. > > Overall I think the implementation looks okay but one thing to think > about is errors, WaitForSingleObject can fail with other errors, the > return from kill is not checked. > > I don't have time to study the test is detail just now but I suspect > invoking "./ProcessKillTest.sh" will need to change as the script will > be in test.src and may not have execute permission. Also I see tests > for specific exit codes which may be problematic (and will need to be > updated for MacOSX). For isAlive then it may be better to test it by > adding to existing tests. > > -Alan. > >

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