Reputation: 18864
How to get the name of the JVM TI _jclass? I want to display names of classes loaded in the JVMTI agent, however it is not obvious to me how to get the name of a class from a _jclass instance.
Upvotes: 1
Views: 678
Reputation: 56
Is this what you want?
#include <stdlib.h>
#include "jvmti.h"
jvmtiEnv *globalJVMTIInterface;
void JNICALL vmInit(jvmtiEnv *jvmti_env,JNIEnv* jni_env,jthread thread) {
printf("VMStart\n");
jint numberOfClasses;
jclass *classes;
jint returnCode = (*globalJVMTIInterface)->GetLoadedClasses(globalJVMTIInterface, &numberOfClasses, &classes);
if (returnCode != JVMTI_ERROR_NONE) {
fprintf(stderr, "Unable to get a list of loaded classes (%d)\n", returnCode);
exit(-1);
}
int i;
for(i=0;i<numberOfClasses;i++) {
char* signature = NULL;
char* generic = NULL;
(*globalJVMTIInterface)->GetClassSignature(globalJVMTIInterface, classes[i], &signature, &generic);
printf("%d) %s %s\n", i+1, signature, generic);
if(signature) {
returnCode = (*globalJVMTIInterface)->Deallocate(globalJVMTIInterface, (unsigned char*) signature);
}
if(generic) {
returnCode = (*globalJVMTIInterface)->Deallocate(globalJVMTIInterface, (unsigned char*) generic);
}
}
if(classes) {
returnCode = (*globalJVMTIInterface)->Deallocate(globalJVMTIInterface, (unsigned char*) classes);
}
}
JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
jint returnCode = (*jvm)->GetEnv(jvm, (void **)&globalJVMTIInterface, JVMTI_VERSION_1_0);
if (returnCode != JNI_OK) {
fprintf(stderr, "The version of JVMTI requested (1.0) is not supported by this JVM.\n");
return JVMTI_ERROR_UNSUPPORTED_VERSION;
}
jvmtiEventCallbacks *eventCallbacks;
eventCallbacks = calloc(1, sizeof(jvmtiEventCallbacks));
if (!eventCallbacks) {
fprintf(stderr, "Unable to allocate memory\n");
return JVMTI_ERROR_OUT_OF_MEMORY;
}
eventCallbacks->VMInit = &vmInit;
returnCode = (*globalJVMTIInterface)->SetEventCallbacks(globalJVMTIInterface, eventCallbacks, (jint) sizeof(*eventCallbacks));
if (returnCode != JNI_OK) {
fprintf(stderr, "JVM does not have the required capabilities (%d)\n", returnCode);
exit(-1);
}
returnCode = (*globalJVMTIInterface)->SetEventNotificationMode(globalJVMTIInterface, JVMTI_ENABLE, JVMTI_EVENT_VM_INIT, (jthread) NULL);
if (returnCode != JNI_OK) {
fprintf(stderr, "JVM does not have the required capabilities, JVMTI_ENABLE, JVMTI_EVENT_VM_INIT (%d)\n", returnCode);
exit(-1);
}
return JVMTI_ERROR_NONE;
}
Upvotes: 3
Reputation: 108909
I believe you can determine it from GetClassSignature
(not that I've tried it).
Upvotes: 1