[EXTERNAL] Re: JDK-8234076 bug fix candidate

[Nikola Grcevski]

Hi Kumar,

Thank you so much for your input! You are absolutely correct, this fix doesn’t fix the argument expansion issue on Windows, it only fixes the crash. I made a similar comment in my original email, fixing the argument expansion would be a bit more substantial change. I’m more than happy to do it, I would just need some guidance on what testing needs to be done to ensure that the argument expansion fix doesn’t break some existing behaviour.

I also wanted to clarify that, the command line as specified below, doesn’t expose the issue with negative array index that was reported in JDK- 8234076, however a later check already present in the code prevents argument expansion to run on Windows.

I must apologize, I’m new to this project and I really don’t know what’s the appropriate team etiquette in OpenJDK for handling situations like these. I’ve worked on teams where when a specific issue is reported other uncovered problems are fixed too, and also on teams where people tend to fix the reported problem and then file new bug reports for other uncovered problems. I’m happy to do either. 

Thank you!
Nikola

From: Kumar Srinivasan <ksrinifmt at gmail.com> 
Sent: December 3, 2019 10:14 AM
To: Nikola Grcevski <Nikola.Grcevski at microsoft.com>
Cc: Henry Jen <henry.jen at oracle.com>; Alan Bateman <Alan.Bateman at oracle.com>; core-libs-dev at openjdk.java.net
Subject: Re: [EXTERNAL] Re: JDK-8234076 bug fix candidate

Hi,

Sorry for chiming in  late in the review process, for what it's worth....

1. It is not at all clear to me if this solution is correct, yes it averts the problem of not finding the main-class
    and subsequent crash,  but it does not address  wildcard arguments expansion.

    What if we have
    % java --module-path=mods --module=jdk.compiler/com.sun.tools.javac.Main *.java
    Where jdk.compiler is a java compiler implementation (javac).
    The user would expect the above compiler module to build all the .java files in that directory, 
    and this fix will not address that.

Some background:
https://bugs.openjdk.java.net/browse/JDK-7146424
Please see all the related bugs in the above JIRA issue.

Paragraph #6 in this interview surmises the wild card behavior on  Windows:
https://www.princeton.edu/~hos/mike/transcripts/kernighan.htm

2. Though the arguments related tests are in Aaarghs.java the modules related tests for the launcher are at:
https://hg.openjdk.java.net/jdk/jdk13/file/0368f3a073a9/test/jdk/tools/launcher/modules/basic
Using the modules test framework may make the test simpler.

Kumar Srinivasan


On Mon, Dec 2, 2019 at 11:34 AM Nikola Grcevski <Nikola.Grcevski at microsoft.com> wrote:
Hi Alan and Henry,

Thank you for reviewing my email! Henry's observation matches mine, the shared common code for all platforms in checkArg (src/java.base/share/native/libjli/args.c) can potentially leave the firstAppArgIndex static set to -1, if all passed command line arguments are prefixed with a dash. Later on the arguments are validated, however we might crash before then on Windows because of the negative index access. In this case, the customer command was valid (modules usage) and the program runs successfully.

I created a webrev here for the change, including a new test in Arrrghs.java:

https://grcevski.github.io/JDK-8234076/webrev/

I copied the test validation and assertion style of other code inside the test class.

Please let me know if you have any comments or suggestions.

Thanks again!

-----Original Message-----
From: Henry Jen <henry.jen at oracle.com> 
Sent: December 2, 2019 12:26 PM
To: Alan Bateman <Alan.Bateman at oracle.com>
Cc: Nikola Grcevski <Nikola.Grcevski at microsoft.com>; core-libs-dev at openjdk.java.net
Subject: [EXTERNAL] Re: JDK-8234076 bug fix candidate

The fix looks reasonable to me, basically, if the command argument format is not legal, it’s possible we won’t find the main class when doing argument file expansion, and the index is -1 which could cause crash on Windows platform for the wildcard processing.

I think we should add a test case for this, probably in test/jdk/tools/launcher/Arrrghs.java.

As I understand it, the argument validation is done in a later stage after calling JLI_Launch.

Cheers,
Henry


> On Dec 2, 2019, at 2:12 AM, Alan Bateman <Alan.Bateman at oracle.com> wrote:
> 
> On 20/11/2019 19:42, Nikola Grcevski wrote:
>> :
>> 
>> Please let me know if this approach is acceptable for the current bug report and I'll make a webrev and include appropriate launcher tests. I was thinking the tests should do extra validation on the output from _JAVA_LAUNCHER_DEBUG on Windows.
>> 
> I think you're in the right area but I would have expected the arg index to 0 here. Henry Jen (cc'ed) might have some comments on this.
> 
> -Alan