8220684: Process.waitFor(long, TimeUnit) can return false for a process that exited within the timeout

Reviewed-by: prappo, dholmes, rriggs
This commit is contained in:
Ivan Gerasimov 2019-03-16 15:05:21 -07:00
parent 07b560a1a1
commit c07c8d3eea
2 changed files with 89 additions and 14 deletions
src/java.base/share/classes/java/lang
test/jdk/java/lang/Process

@ -1,5 +1,5 @@
/*
* Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -206,20 +206,20 @@ public abstract class Process {
public boolean waitFor(long timeout, TimeUnit unit)
throws InterruptedException
{
long startTime = System.nanoTime();
long rem = unit.toNanos(timeout);
long remainingNanos = unit.toNanos(timeout); // throw NPE before other conditions
if (hasExited())
return true;
if (timeout <= 0)
return false;
long deadline = System.nanoTime() + remainingNanos;
do {
try {
exitValue();
Thread.sleep(Math.min(TimeUnit.NANOSECONDS.toMillis(remainingNanos) + 1, 100));
if (hasExited())
return true;
} catch(IllegalThreadStateException ex) {
if (rem > 0)
Thread.sleep(
Math.min(TimeUnit.NANOSECONDS.toMillis(rem) + 1, 100));
}
rem = unit.toNanos(timeout) - (System.nanoTime() - startTime);
} while (rem > 0);
remainingNanos = deadline - System.nanoTime();
} while (remainingNanos > 0);
return false;
}
@ -320,11 +320,20 @@ public abstract class Process {
* @since 1.8
*/
public boolean isAlive() {
return !hasExited();
}
/**
* This is called from the default implementation of
* {@code waitFor(long, TimeUnit)}, which is specified to poll
* {@code exitValue()}.
*/
private boolean hasExited() {
try {
exitValue();
return false;
} catch(IllegalThreadStateException e) {
return true;
} catch (IllegalThreadStateException e) {
return false;
}
}

@ -0,0 +1,66 @@
/*
* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8220684
* @summary Process.waitFor(long, TimeUnit) can return false for a process
* that exited within the timeout
* @run main/othervm WaitFor
*/
import java.io.InputStream;
import java.io.OutputStream;
import java.util.concurrent.TimeUnit;
public class WaitFor {
public static void main(String[] args) throws Throwable {
int failCnt = 0;
for (int i = 0; i < 30; ++i) {
Process proc = new MyProcess(new ProcessBuilder("true").start());
boolean exited = proc.waitFor(100, TimeUnit.MILLISECONDS);
if (!exited && !proc.isAlive()) failCnt++;
}
if (failCnt > 10) {
throw new RuntimeException(failCnt + " processes were still alive"
+ " after timeout");
}
}
}
/**
* This class uses the default implementation of java.lang.Process#waitFor(long,
* TimeUnit), and delegates all other calls to the actual implementation of
* Process.
*/
class MyProcess extends Process {
Process impl;
public MyProcess(Process impl) { this.impl = impl; }
public OutputStream getOutputStream() { return impl.getOutputStream(); }
public InputStream getInputStream() { return impl.getInputStream(); }
public InputStream getErrorStream() { return impl.getErrorStream(); }
public int waitFor() throws InterruptedException { return impl.waitFor(); }
public int exitValue() { return impl.exitValue(); }
public void destroy() { impl.destroy(); }
public ProcessHandle toHandle() { return impl.toHandle(); }
}