RFR(s): 8212828: (process) Change the Process launch mechanism default on Linux to be posix_spawn

[Roger Riggs]

Hi Thomas,

The new OutputAnalyzer methods are new:

496: now that we have Immutable Lists, can the filterByKeyword argument 
be a List<String>?

List<String> interesting = List.of( "fork", "clone", "vfork", "exec", 
"/bin/true", "jspawnhelper" );

497: Instead of passing an int, pass the String itself
480, 485: that is returned from getStdout() or getStderr().

The body of the method could probably be nicely written using the Stream 
API.
(except for the line numbers).  I'm not sure the line numbers are useful 
in this case
based since the strace output is not shown anywhere or seen in the full.

    <string>.lines().filter()...

Add the javadoc to the methods so its clear how to use them since this 
is a public test framework.

Regards, Roger


On 02/08/2019 04:38 AM, Thomas Stüfe wrote:
> Hi Roger, Martin,
>
> next version:
>
> http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.02/webrev 
> <http://cr.openjdk.java.net/%7Estuefe/webrevs/8213192--%28process%29-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.02/webrev>
>
> - did massage the comment in ProcessImpl.c
> - made the test more resilient by scanning for the strace tool and by 
> silently ignoring all problems stemming from strace or the payload 
> binary not being there. The test now only fails if the forks were 
> successully executed but it does not seem to use posix-spawn.
> - added output to the test by printing the "interesting" lines of the 
> strace output. Note that this filtering is not really sophisticated 
> and will show all thread related clone() calls as well:
>
> 614   [pid 12447] <... clone resumed> child_stack=0x7fe00c4baff0, 
> flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, 
> parent_tidptr=0x7fe00c4bb9d0, tls=0x7fe00c4bb700, 
> child_tidptr=0x7fe00c4bb9d0) = 12452
> 646   [pid 12447] clone(/usr/bin/strace: Process 12453 attached
> 649   [pid 12447] <... clone resumed> child_stack=0x7fe00c3b9ff0, 
> flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, 
> parent_tidptr=0x7fe00c3ba9d0, tls=0x7fe00c3ba700, 
> child_tidptr=0x7fe00c3ba9d0) = 12453
> ....
>
> I am sure this could be made more intelligent but lets keep it simple 
> for now.
>
> - I removed the helperPath() methods Roger mentioned, they are not 
> needed anymore.
>
> @Martin: I like the -e signal=none -e trace=process idea but I'm not 
> sure if all versions of strace support these options. I think the 
> strace output is small enough for this small use case, some kB only.
>
> Cheers, Thomas
>
>
>
>
>
> On Thu, Feb 7, 2019 at 6:01 PM Thomas Stüfe <thomas.stuefe at gmail.com 
> <mailto:thomas.stuefe at gmail.com>> wrote:
>
>     Hi all,
>
>     second version, including the updated comment in ProcessImpl.c
>     Martin requested:
>
>     http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.01/webrev/index.html
>     <http://cr.openjdk.java.net/%7Estuefe/webrevs/8213192--%28process%29-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.01/webrev/index.html>
>
>     @Roger: thanks for feeding this into your tests. I still try to
>     get it to run thru jdk-submit, but that seems to be stuck again..
>
>     Cheers, Thomas
>
>
>
>
>
>     On Wed, Feb 6, 2019 at 10:29 AM Thomas Stüfe
>     <thomas.stuefe at gmail.com <mailto:thomas.stuefe at gmail.com>> wrote:
>
>         Hi all
>
>         Bug: https://bugs.openjdk.java.net/browse/JDK-8213192
>         webrev:
>         http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.00/webrev/index.html
>         <http://cr.openjdk.java.net/%7Estuefe/webrevs/8213192--%28process%29-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.00/webrev/index.html>
>
>         (@Roger: I hope you do not mind? The bug is assigned to you
>         but since I happened to play around with posix_spawn I
>         prepared this webrev. If you rather do this change, that is
>         fine and I will leave it to you.)
>
>         When we added the possibility to use posix_spawn as underlying
>         implementation for Runtime.exec() on Linux with
>         https://bugs.openjdk.java.net/browse/JDK-8212828, we agreed to
>         keep VFORK as default until work on 13 starts. So now would be
>         a good time to switch the default to posix_spawn to get a good
>         testing window. Note that at SAP we run our VMs internally
>         with posix_spawn as default since some months and have not
>         seen problems.
>
>         As for the fix, I added a test which tests that the default is
>         indeed posix_spawn - not sure whether this is overdoing it
>         though. Also, I use strace for the test, and /bin/true, and
>         while strace is usually available and reachable by path
>         resolution, I am afraid on some test machines it may not. What
>         do you think, should I leave the test out?
>
>         The fix ran through all java/lang/ProcessBuilder jtreg tests ok.
>
>         Thanks, Thomas
>