This is just normal way of thinking. :) Thanks, Serguei
On 9/16/16 07:37, Daniel D. Daugherty wrote:
Going down the JNI rabbit hole is my fault. When I mumbled on 2016-09-02 about how this bug might be fixed, I was too focused on the fact that the JNI layer didn't do what we want and I talked about how to fix it using JNI functions.Harold, my apologies for wasting your time. Dan On 9/16/16 8:32 AM, harold seigel wrote:Hi Serguei, Thanks for the suggestion! That provides a much cleaner implementation. Harold On 9/15/2016 11:28 PM, serguei.spit...@oracle.com wrote:On 9/15/16 19:13, David Holmes wrote:On 16/09/2016 8:52 AM, serguei.spit...@oracle.com wrote:Hi Harold,I did not got deep into the fix yet but wonder why the JVMTI function isMy copy-paste failed. I wanted to list the JVMTI function name: GetMethodDeclaringClass. Thanks, Sergueinot used.I was wondering a similar thing. It seems very heavyweight to use Java level reflection from inside native code to validate the native "handles" passed to that native code. I would have expected a way to go from a MethodId to the declaring class of the method, and a simple way to test if there is an ancestor relation between the two classes.On 9/15/16 13:05, harold seigel wrote:One could argue that a spec compliant JNI implementation wouldn't needthis change in the first place...Regardless, I'm withdrawing this change because I found that it failsa com/sun/jdi JTreg test involving static methods in interfaces.I find it both intriguing and worrying that ClassType.InvokeMethod refers to superinterfaces when prior to 8 (and this spec was not updated in this area) static interface methods did not exist! The main changes were in the definition of InterfaceType.InvokeMethod. I wonder whether invocation of static interface methods via ClassType.InvokeMethod is actually tested directly?I realize the specs are a bit of a minefield when it comes to what is required by the different specs and what is implemented in hotspot. Unfortunately it is a minefield I also have to wade through for private interface methods. In many cases it is not clear what should happen and all we have to guide us is what hotspot does (eg "virtual" invocations on non-virtual methods).David -----Thanks, Harold On 9/15/2016 3:37 PM, Daniel D. Daugherty wrote:On 9/15/16 12:10 PM, harold seigel wrote:(Adding hotspot-runtime) Hi Dan, Thanks for looking at this. I could pass NULL instead of clazz to ToReflectMethod() to ensure that the method object isn't being obtained from clazz.I don't think that would be a JNI spec compliant use of the JNI ToReflectedMethod() function. That would be relying on the fact that HotSpot doesn't use the clazz parameter to convert {clazz,jmethodID} => method_object. Sorry... again... DanHarold On 9/15/2016 1:09 PM, Daniel D. Daugherty wrote:On 9/15/16 9:31 AM, harold seigel wrote:Hi, Please review this small fix for JDK-8160987. The JDWP InvokeStatic() method was depending on the JNI function that it called to enforce the requirement that the specified method must be a member of the specified class or one of its super classes.But, JNI does not enforce this requirement. This fix adds code to JDWP to do its own check that the specified method is a member ofthe specified class or one of its super classes. JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8160987 Open webrev: http://cr.openjdk.java.net/~hseigel/bug_8160987/src/jdk.jdwp.agent/share/native/libjdwp/invoker.c Sorry I didn't think of this comment during the pre-review... The only "strange" part of this fix is:L374: /* Get the method object from the method's jmethodID. */ L375: method_object = JNI_FUNC_PTR(env,ToReflectedMethod)(env,L376: clazz, L377: method, L378: JNI_TRUE /* isStatic */); L379: if (method_object == NULL) {L380: return JVMTI_ERROR_NONE; /* Bad jmethodID ? Thiswill be handled elsewhere */ L381: }Here we are using parameter 'clazz' to find the method_object for parameter 'method' so that we can validate that 'clazz' refers tomethod's class or superclass.When a bogus 'clazz' value is passed in by a JCK test, the onlyreason that JNI ToReflectedMethod() can still find the right method_object is that our (HotSpot) implementation of JNIToReflectedMethod() doesn't really require the 'clazz' parameter to find the right method_object. So the 'method_object' that wereturn is the real one which has a 'clazz' field that doesn't match the 'clazz' parameter. Wow does that twist your head around or what? So we're trusting JNI ToReflectedMethod() to return the rightmethod_object when we give it a potentially bad 'clazz' value.So should we use JNI FromReflectedMethod() to convert the method_object back into a jmethodID and verify that jmethodID matches the one that we passed to check_methodClass()? I might be too paranoid here so feel free to say that enough is enough with this fix. Thumbs up! DanThe fix was tested with the two failing JCK vm/jdwp tests listed in the bug, the JCK Lang, VM, and API tests, the hotspot JTReg tests, the java/lang, java/util and other JTReg tests, theco-located and non-colocated NSK tests, and with the RBT Tier2 tests.Thanks, Harold