Name: vsR10008 Date: 09/10/2003



JVMTI spec says:

"Dispose Environment

jvmtiError
DisposeEnvironment(jvmtiEnv* env)

Shutdown a JVMTI connection created with JNI GetEnv (see JVMTI Environments).
Dispose of any resources held by the environment."

According to spec capabilities set is one of resources held by environment:

"JVMTI Environments

The JVMTI specification supports the use of multiple simultaneous JVMTI agents.
Each agent has its own JVMTI environment. That is, the JVMTI state is separate
for each agent - changes to one environment do not affect the others. The state
of a JVMTI environment includes:

     * the event callbacks
     * the set of events which are enabled
     * the capabilities
     * the memory allocation/deallocation hooks"

Therefore invocation of DisposeEnvironment should relinquish all the capabilities
the specified environment currently possesses.

The current RI doesn't dispose enviromnent properly. To reproduce bug please run
the following shell script (do not forget to change the definition of JDK_PATH
in the first line):

--- File: runme.sh -----------------------------------------------------------
JDK_PATH="/java/re/jdk/1.5.0/latest/binaries/solaris-sparc"

JVMTI_H_PATH="${JDK_PATH}/include"
CC="cc"

echo "...creating a.c"
cat - > a.c <<EOF
#include <stdio.h>
#include "jvmti.h"

#define BAD_CODE

static jvmtiEnv *jvmti = NULL;
jvmtiCapabilities pcapa;
jvmtiCapabilities capa;
jvmtiCapabilities capa1;
JavaVM *global_jvm;

JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
       printf("Loaded!\n");
       global_jvm = jvm;
       return JNI_OK;
}

JNIEXPORT void JNICALL
Java_a_check(JNIEnv *env, jclass cls) {
       jvmtiError err;
       jint res;

       res = (*global_jvm)->GetEnv(global_jvm, (void **) &jvmti, JVMTI_VERSION_1_0);
       memset(&capa, 0, sizeof(jvmtiCapabilities));
       capa.can_tag_objects = 1;
       err=(*jvmti)->AddCapabilities(jvmti, &capa);
       if(err != JVMTI_ERROR_NONE) {
           printf("Could not add capability.\n");
           return;
       }
#ifdef WORKAROUND
       err=(*jvmti)->RelinquishCapabilities(jvmti, &capa);
       if(err != JVMTI_ERROR_NONE) {
           printf("Could not relinquish capability.\n");
           return;
       }
#endif
       printf("Disposing JVMTI environment...\n");
       err=(*jvmti)->DisposeEnvironment(jvmti);
       if(err != JVMTI_ERROR_NONE) {
           printf("Could not dispose env.\n");
           return;
       }

       printf("Creating new JVMTI environment...\n");
       res = (*global_jvm)->GetEnv(global_jvm, (void **) &jvmti, JVMTI_VERSION_1_0);
       err=(*jvmti)->AddCapabilities(jvmti, &capa);
       if(err != JVMTI_ERROR_NONE) {
           printf("*********************************\n");
           printf("*** Could not add capability. ***\n");
           printf("*********************************\n");
           return;
       }
       printf("Finished!\n");
}

EOF

echo "...creating liba.so"

${CC} -G -KPIC -o liba.so -I${JDK_PATH}/include -I${JDK_PATH}/include/solaris -I${JVMTI_H_PATH} a.c

echo "...creating a.java"

cat - > a.java <<EOF
public class a {
       native static void check();
       public static void main(String[] args) {
           System.loadLibrary("a");
           check();
       }
}
EOF

echo "...creating a.class"

${JDK_PATH}/bin/javac -d . a.java

echo "...running a.class"
LD_LIBRARY_PATH=. CLASSPATH=. ${JDK_PATH}/bin/java -showversion -agentlib:a a

echo "...creating WORKAROUND version of liba.so"
${CC} -G -KPIC -o liba.so -I${JDK_PATH}/include -I${JDK_PATH}/include/solaris -I${JVMTI_H_PATH} -DWORKAROUND a.c

echo "...running a.class with workaround"
LD_LIBRARY_PATH=. CLASSPATH=. ${JDK_PATH}/bin/java -agentlib:a a

--- End of file: runme.sh ----------------------------------------------------

The output is:

---------------------------------------------------------------------------
...creating a.c
...creating liba.so
...creating a.java
...creating a.class
...running a.class
Loaded!
java version "1.5.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-beta-b18)
Java HotSpot(TM) Client VM (build 1.5.0-beta-b18, mixed mode)

Disposing JVMTI environment...
Creating new JVMTI environment...
*********************************
*** Could not add capability. ***
*********************************

...creating WORKAROUND version of liba.so
...running a.class with workaround
Loaded!
Disposing JVMTI environment...
Creating new JVMTI environment...
Finished!
---------------------------------------------------------------------------


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