Request for review: 8006298: Specifying malformed JFR options (--XX:+FlightRecorderOptions) outputs non-sensical error

[harold seigel]

Hi,

Thank you for your comments!

Please review this updated webrev: 
http://cr.openjdk.java.net/~hseigel/bug_8006298_2/ 
<http://cr.openjdk.java.net/%7Ehseigel/bug_8006298_2/>

It avoids the 'const' and '\0' issues by determining the length of the 
argument and passing it to find_flag().

This changes the output messages slightly, by including the '=...' 
text.  For example:

      % $JAVA_HOME/bin/java -XX:+UseLargePages=8 -version
    Improperly specified VM option 'UseLargePages=8'

    % $JAVA_HOME/bin/java -XX:-ObjectAlignmentInBytes=16 -version
    Unexpected +/- setting in VM option 'ObjectAlignmentInBytes=16'

Thanks, Harold


On 1/30/2013 10:39 PM, Vitaly Davidovich wrote:
>
> I'd also change "equal_sign[0] = 0;" to "equal_sign[0] = '\0';" if 
> this line is to be kept - it's more idiomatic.
>
> Thanks
>
> Sent from my phone
>
> On Jan 30, 2013 8:34 PM, "Mikael Vidstedt" <mikael.vidstedt at oracle.com 
> <mailto:mikael.vidstedt at oracle.com>> wrote:
>
>
>     Harold,
>
>     Thanks for doing this, I like the improved messages a lot!
>
>     One small question:
>
>     The first argument to process_argument is a "const char* arg".
>     argname is also const, based on arg. You do this:
>
>     char* equal_sign = (char *)strrchr(argname, '=');
>     if (equal_sign > argname)
>     equal_sign[0] = 0;
>
>     Doesn't that effectively break the const'ness of the incoming
>     argument?
>
>     Cheers,
>     Mikael
>
>     On 2013-01-30 10:51, harold seigel wrote:
>>     Hi,
>>
>>     Please review the following change to fix bug 8006298.
>>
>>     Summary:
>>     This change enables hotspot to emit more useful messages when
>>     Java options are specified incorrectly.
>>
>>     This was tested using JCK, UTE, and JTREG tests, and by hand. 
>>     Below are the test cases that were run by hand.  Please let me
>>     know if you have any additional suggestions.  (The "Error:..."
>>     messages appeared in all cases but are only shown for the initial
>>     case.)
>>
>>         $JAVA_HOME/bin/java -XX:UseLargePages -version
>>         Missing +/- setting for VM option 'UseLargePages'
>>         Error: Could not create the Java Virtual Machine.
>>         Error: A fatal exception has occurred. Program will exit.
>>
>>         $JAVA_HOME/bin/java -XX:+UseLargePages=8 -version
>>         Improperly specified VM option 'UseLargePages'
>>
>>         $JAVA_HOME/bin/java -XX:ObjectAlignmentInBytes=v -version
>>         Improperly specified VM option 'ObjectAlignmentInBytes'
>>
>>         $JAVA_HOME/bin/java -XX:-ObjectAlignmentInBytes=16 -version
>>         Unexpected +/- setting in VM option 'ObjectAlignmentInBytes'
>>         <-- 64 bit VM's
>>         Unrecognized VM option 'ObjectAlignmentInBytes' <-- 32 bit VM's
>>
>>         $JAVA_HOME/bin/java -XX:bogus_option -version
>>         Unrecognized VM option 'bogus_option'
>>
>>     Open webrev at http://cr.openjdk.java.net/~hseigel/bug_8006298/
>>     <http://cr.openjdk.java.net/%7Ehseigel/bug_8006298/>
>>
>>     Bug link at http://bugs.sun.com/view_bug.do?bug_id=8006298
>>
>>     Thanks!  Harold
>
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