RFR 8157310: jdk.dynalink.linker.support.Lookup should have more checks before adding module read link

[Sundararajan Athijegannathan]

Hi,

Thanks for the review. But, I adjusted the change slightly -- moved
addModuleRead and caller-sensitive fallback attempt to
CallerSensitiveDynamicMethod itself - leaving Lookup as general
exception translating version of j.l.invoke.MethodHandle.Lookup.

I think this is better caller sensitivity handling moved to specific
place and Lookup remains a generic API.

http://cr.openjdk.java.net/~sundar/8157310/webrev.01/

Thanks,

-Sundar


On 5/20/2016 12:22 PM, Attila Szegedi wrote:
> +1. Nice work!
>
>> On 19 May 2016, at 15:28, Sundararajan Athijegannathan <sundararajan.athijegannathan at oracle.com> wrote:
>>
>> Please review http://cr.openjdk.java.net/~sundar/8157310/ for
>> https://bugs.openjdk.java.net/browse/JDK-8157310
>>
>> What is this fix?
>>
>> * When unreflecting caller sensitive methods, dynalink uses specific
>> Lookup of actual caller (instead of publicLookup) - in nashorn's case
>> it's be the Lookup of script class.
>>
>> * Script class may not have read link to the module of the class (of
>> caller sensitive member). If there is any IllegalAccessError, dynalink
>> adds the read link and tries to
>>
>> unreflect again. We don't want unnecessary module link read in such
>> cases. Check has been added whether the package is exported from
>> declaring module. Note that there is no security issue here.  Even
>> before the fix, module read edge does not give any capability. unreflect
>> call after adding unnecessary read line would still fail for
>> non-exported package case. There were unnecessary module read links
>> created - which is being avoided now.
>>
>> * Additional "API" in Lookup.java slipped from jigsaw code into
>> jdk9-dev. Those unreflectCallerSensitive and
>> unreflectConstructorCallerSensitive were meant to be 'interim' somehow
>> slipped.  Now, only unreflect and unreflectConstructor in Lookup. Caller
>> sensitiveness is hidden in the implementation.  These methods were never
>> APIs when dynalink API was created.
>>
>> Thanks,
>>
>> -Sundar
>>
>>