Find the names of all classes loaded by Java using reflection

Question

To support the static analysis tool, I want to use the tool or control the Java program so that I can define for each reflective call (for example, Method.invoke (..)):

1.), into the class C of which it is called, and 2.) which the classloader loaded this class C.

Ideally, I am looking for a solution that does not require me to statically change the Java Runtime Library, i.e. I am looking for a solution to load time. However, the solution should be able to capture all reflective calls, even those that occur in the Java Runtime library itself. (I played with ClassFileTransformer, but this only seems to apply to classes that ClassFileTransformer itself does not depend on. In particular, ClassFileTransfomer does not apply to the Class class.)

Thanks!

Answer 1

-, ? , ? , , . JProfiler, , . - Java. , , .

-, , Javassist CGLib, , AspectJ (AOP). , , , , , , , .

Answer 2

API, , , , JVMTI. JVMTI , JVM, MethodEntry, MethodExit. Method.invoke. API . C ++.

, java.lang.reflect.Method.invoke . , , , , .

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <jvmti.h>

static jvmtiEnv *jvmti = NULL;
static jvmtiCapabilities capa;

static jint check_jvmti_error(jvmtiEnv *jvmti,
                              jvmtiError errnum,
                              const char *str) {

    if (errnum != JVMTI_ERROR_NONE) {
        char *errnum_str;
        errnum_str = NULL;
        (void) (*jvmti)->GetErrorName(jvmti, errnum, &errnum_str);
        printf("ERROR: JVMTI: %d(%s): %s\n",
               errnum,
               (errnum_str == NULL ? "Unknown" : errnum_str),
               (str == NULL ? "" : str));
        return JNI_ERR;
    }
    return JNI_OK;
}

void JNICALL callbackMethodEntry(jvmtiEnv *jvmti_env,
                                 JNIEnv* jni_env,
                                 jthread thread,
                                 jmethodID method) {

    char* method_name;
    char* method_signature;
    char* generic_ptr_method;
    char* generic_ptr_class;
    char* class_name;
    jvmtiError error;
    jclass clazz;

    error = (*jvmti_env)->GetMethodName(jvmti_env,
                                        method,
                                        &method_name,
                                        &method_signature,
                                        &generic_ptr_method);
    if (check_jvmti_error(jvmti_env, error, "Failed to get method name")) {
        return;
    }

    if (strcmp("invoke", method_name) == 0) {

        error
                = (*jvmti_env)->GetMethodDeclaringClass(jvmti_env, method,
                        &clazz);
        if (check_jvmti_error(jvmti_env, error,
                "Failed to get class for method")) {
            (*jvmti_env)->Deallocate(jvmti_env, method_name);
            (*jvmti_env)->Deallocate(jvmti_env, method_signature);
            (*jvmti_env)->Deallocate(jvmti_env, generic_ptr_method);
            return;
        }

        error = (*jvmti_env)->GetClassSignature(jvmti_env, clazz, &class_name,
                &generic_ptr_class);
        if (check_jvmti_error(jvmti_env, error, "Failed to get class signature")) {
            (*jvmti_env)->Deallocate(jvmti_env, method_name);
            (*jvmti_env)->Deallocate(jvmti_env, method_signature);
            (*jvmti_env)->Deallocate(jvmti_env, generic_ptr_method);
            return;
        }

        if (strcmp("Ljava/lang/reflect/Method;", class_name) == 0) {
            printf("Method entered: %s.%s.%s\n", class_name, method_name,
                    method_signature);
        }
        (*jvmti_env)->Deallocate(jvmti_env, class_name);
        (*jvmti_env)->Deallocate(jvmti_env, generic_ptr_class);
    }

    (*jvmti_env)->Deallocate(jvmti_env, method_name);
    (*jvmti_env)->Deallocate(jvmti_env, method_signature);
    (*jvmti_env)->Deallocate(jvmti_env, generic_ptr_method);
}

JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {

    jint result;
    jvmtiError error;
    jvmtiEventCallbacks callbacks;

    result = (*jvm)->GetEnv(jvm, (void**) &jvmti, JVMTI_VERSION_1_0);
    if (result != JNI_OK || jvmti == NULL) {
        printf("error\n");
        return JNI_ERR;
    } else {
        printf("loaded agent\n");
    }

    (void) memset(&capa, 0, sizeof(jvmtiCapabilities));
    capa.can_generate_method_entry_events = 1;

    error = (*jvmti)->AddCapabilities(jvmti, &capa);
    if (check_jvmti_error(jvmti, error, "Unable to set capabilities") != JNI_OK) {
        return JNI_ERR;
    }

    (void) memset(&callbacks, 0, sizeof(callbacks));
    callbacks.MethodEntry = &callbackMethodEntry;
    error = (*jvmti)->SetEventCallbacks(jvmti,
                                        &callbacks,
                                        (jint) sizeof(callbacks));
    if (check_jvmti_error(jvmti, error, "Unable to set callbacks") != JNI_OK) {
        return JNI_ERR;
    }

    error = (*jvmti)->SetEventNotificationMode(jvmti,
                                               JVMTI_ENABLE,
                                               JVMTI_EVENT_METHOD_ENTRY,
                                               (jthread) NULL);
    if (check_jvmti_error(jvmti, error,
            "Unable to set method entry notifications") != JNI_OK) {
        return JNI_ERR;
    }

    return JNI_OK;
}