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https://issues.apache.org/jira/browse/EXEC-57?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13124479#comment-13124479
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Siegfried Goeschl commented on EXEC-57:
---------------------------------------
BTW
nohup sleep 10 1>/dev/null 2>/dev/null 0</dev/null &
would work since the process would be really decoupled
> DefaultExecutor.execute() does not return even if child process terminated
> --------------------------------------------------------------------------
>
> Key: EXEC-57
> URL: https://issues.apache.org/jira/browse/EXEC-57
> Project: Commons Exec
> Issue Type: Bug
> Affects Versions: 1.1
> Environment: > uname -smr
> HP-UX B.11.23 ia64
> $ uname -smr
> Linux 2.6.18-194.3.1.el5xen x86_64
> Reporter: Nickolay Martinov
> Assignee: Siegfried Goeschl
> Attachments: EXEC-57.test.patch
>
>
> When script that starts background process is synchronously executed via
> DefaultExecutor.execute() then method never returns (until child process
> spawned by child process terminates).
> Here is example if such script:
> echo "Going to start daemon process"
> sleep 1
> cd ./target
> nohup sleep 10 &
> sleep 1
> echo "Daemon process was started"
> Stream handler is used to grab and print output of script. As can be seen
> from stack trace problem lies in pump threads that call InputStream.read()
> that does not return when script that we invoke terminates. Instead it
> returns only once process started by script terminates.
> "Thread-3" daemon prio=10 tid=00c73a00 nid=17 lwp_id=2640638 runnable
> [2e180000]
> java.lang.Thread.State: RUNNABLE
> at java.io.FileInputStream.readBytes(Native Method)
> at java.io.FileInputStream.read(FileInputStream.java:177)
> at
> java.lang.UNIXProcess$DeferredCloseInputStream.read(UNIXProcess.java:313)
> at org.apache.commons.exec.StreamPumper.run(StreamPumper.java:105)
> at java.lang.Thread.run(Thread.java:662)
> Locked ownable synchronizers:
> - None
> "Thread-2" daemon prio=10 tid=005fd000 nid=16 lwp_id=2640637 runnable
> [2e240000]
> java.lang.Thread.State: RUNNABLE
> at java.io.FileInputStream.readBytes(Native Method)
> at java.io.FileInputStream.read(FileInputStream.java:199)
> at
> java.lang.UNIXProcess$DeferredCloseInputStream.read(UNIXProcess.java:322)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> - locked <628b1970> (a java.io.BufferedInputStream)
> at java.io.FilterInputStream.read(FilterInputStream.java:90)
> at org.apache.commons.exec.StreamPumper.run(StreamPumper.java:105)
> at java.lang.Thread.run(Thread.java:662)
> Locked ownable synchronizers:
> - None
> "main" prio=10 tid=0046aa00 nid=1 lwp_id=-1 in Object.wait() [7fff8000]
> java.lang.Thread.State: WAITING (on object monitor)
> at java.lang.Object.wait(Native Method)
> - waiting on <627e4968> (a java.lang.Thread)
> at java.lang.Thread.join(Thread.java:1186)
> - locked <627e4968> (a java.lang.Thread)
> at java.lang.Thread.join(Thread.java:1239)
> at
> org.apache.commons.exec.PumpStreamHandler.stop(PumpStreamHandler.java:171)
> at
> org.apache.commons.exec.DefaultExecutor.executeInternal(DefaultExecutor.java:363)
> at
> org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:160)
> at
> org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:147)
> I added timeout to join() and call interrupt() but that doesnt help to kill
> pump threads. Fortunately, these are daemon threads that do not block JVM
> from exiting. Except from extra daemon threads this solved problem on linux.
> But that wasnt able to prevent all hangs on HP-UX. Check following stack
> "main" prio=10 tid=00465600 nid=1 lwp_id=-1 runnable [7fffd000]
> java.lang.Thread.State: RUNNABLE
> at java.io.FileInputStream.close0(Native Method)
> at java.io.FileInputStream.close(FileInputStream.java:259)
> at
> java.lang.UNIXProcess$DeferredCloseInputStream.close(UNIXProcess.java:298)
> at java.io.BufferedInputStream.close(BufferedInputStream.java:451)
> at
> org.apache.commons.exec.DefaultExecutor.closeStreams(DefaultExecutor.java:281)
> at
> org.apache.commons.exec.DefaultExecutor.executeInternal(DefaultExecutor.java:364)
> at
> org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:160)
> at
> org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:147)
> at
> org.apache.commons.exec.DefaultExecutorTest.testSyncInvocationOfBackgroundProcess(DefaultExecutorTest.java:812)
> I dont have idea how this can be interrupted or timed out except that skip
> closing streams. But in this case we'll probably leak resources.
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