都想看jvm是吧
class_monitor_agent.c
#include <jni.h>
#include <jvmti.h>
#include <stdio.h>
#include <string.h>
static jvmtiEnv* jvmti = NULL;
void JNICALL ClassFileLoadHook(jvmtiEnv* jvmti, JNIEnv* jni,jclass class_being_redefined, jobject loader,const char* name, jobject protection_domain,jint class_data_len, const unsigned char* class_data,jint* new_class_data_len, unsigned char** new_class_data) {if (name != NULL) {printf("类加载: %s\n", name);} else {printf("类加载: 匿名类\n");}
}
JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {jint result;jvmtiCapabilities capabilities;jvmtiEventCallbacks callbacks;result = (*vm)->GetEnv(vm, (void**)&jvmti, JVMTI_VERSION_1_2);if (result != JNI_OK || jvmti == NULL) {printf("无法获取JVM TI环境,错误码: %d\n", result);return JNI_ERR;}memset(&capabilities, 0, sizeof(capabilities));capabilities.can_retransform_classes = 1;capabilities.can_generate_all_class_hook_events = 1;result = (*jvmti)->AddCapabilities(jvmti, &capabilities);if (result != JVMTI_ERROR_NONE) {printf("无法设置JVM TI能力,错误码: %d\n", result);return JNI_ERR;}memset(&callbacks, 0, sizeof(callbacks));callbacks.ClassFileLoadHook = &ClassFileLoadHook;result = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));if (result != JVMTI_ERROR_NONE) {printf("无法设置JVM TI回调,错误码: %d\n", result);return JNI_ERR;}result = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);if (result != JVMTI_ERROR_NONE) {printf("无法启用类加载事件,错误码: %d\n", result);return JNI_ERR;}printf("JVM TI代理初始化成功\n");return JNI_OK;
}
JNIEXPORT void JNICALL Agent_OnUnload(JavaVM* vm) {if (jvmti != NULL) {(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_DISABLE,JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);}printf("JVM TI代理卸载\n");
}
thread_trace_agent.c
#include <jni.h>
#include <jvmti.h>
#include <stdio.h>
#include <string.h>static jvmtiEnv* jvmti = NULL;
void JNICALL ThreadStart(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {jclass thread_class = (*jni)->FindClass(jni, "java/lang/Thread");jmethodID get_name = (*jni)->GetMethodID(jni, thread_class, "getName", "()Ljava/lang/String;");jstring name_str = (jstring)(*jni)->CallObjectMethod(jni, thread, get_name);const char* name = name_str ? (*jni)->GetStringUTFChars(jni, name_str, NULL) : "无名线程";printf("[THREAD START] 名称: %s, 地址: %p\n", name, (void*)thread);if (name_str) {(*jni)->ReleaseStringUTFChars(jni, name_str, name);}
}
void JNICALL ThreadEnd(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread) {jclass thread_class = (*jni)->FindClass(jni, "java/lang/Thread");jmethodID get_name = (*jni)->GetMethodID(jni, thread_class, "getName", "()Ljava/lang/String;");jstring name_str = (jstring)(*jni)->CallObjectMethod(jni, thread, get_name);const char* name = name_str ? (*jni)->GetStringUTFChars(jni, name_str, NULL) : "无名线程";printf("[THREAD END] 名称: %s, 地址: %p\n", name, (void*)thread);if (name_str) {(*jni)->ReleaseStringUTFChars(jni, name_str, name);}
}
JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {jint result;jvmtiCapabilities capabilities;jvmtiEventCallbacks callbacks;result = (*vm)->GetEnv(vm, (void**)&jvmti, JVMTI_VERSION_1_2);if (result != JNI_OK || jvmti == NULL) {printf("无法获取JVM TI环境,错误码: %d\n", result);return JNI_ERR;}memset(&capabilities, 0, sizeof(capabilities));result = (*jvmti)->AddCapabilities(jvmti, &capabilities);if (result != JVMTI_ERROR_NONE) {printf("警告: 能力设置部分失败,错误码: %d\n", result);}memset(&callbacks, 0, sizeof(callbacks));callbacks.ThreadStart = &ThreadStart;callbacks.ThreadEnd = &ThreadEnd;result = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));if (result != JVMTI_ERROR_NONE) {printf("无法设置回调,错误码: %d\n", result);return JNI_ERR;}result = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_THREAD_START, NULL);if (result != JVMTI_ERROR_NONE) {printf("无法启用线程启动事件,错误码: %d\n", result);return JNI_ERR;}result = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_THREAD_END, NULL);if (result != JVMTI_ERROR_NONE) {printf("无法启用线程结束事件,错误码: %d\n", result);return JNI_ERR;}printf("线程跟踪代理初始化成功\n");return JNI_OK;
}
JNIEXPORT void JNICALL Agent_OnUnload(JavaVM* vm) {if (jvmti != NULL) {(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_DISABLE, JVMTI_EVENT_THREAD_START, NULL);(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_DISABLE, JVMTI_EVENT_THREAD_END, NULL);}
}
exception_trace_agent.c
#include <jni.h>
#include <jvmti.h>
#include <stdio.h>
#include <string.h>static jvmtiEnv* jvmti = NULL;
void JNICALL ExceptionCatch(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread, jmethodID method, jlocation location, jthrowable exception) {jclass ex_class = (*jni)->GetObjectClass(jni, exception);char* ex_class_name;(*jvmti)->GetClassSignature(jvmti, ex_class, &ex_class_name, NULL);jmethodID get_message = (*jni)->GetMethodID(jni, ex_class, "getMessage", "()Ljava/lang/String;");jstring message_str = (jstring)(*jni)->CallObjectMethod(jni, exception, get_message);const char* message = message_str ? (*jni)->GetStringUTFChars(jni, message_str, NULL) : "无消息";printf("[EXCEPTION CAUGHT] 类型: %s, 消息: %s\n", ex_class_name, message);(*jvmti)->Deallocate(jvmti, (unsigned char*)ex_class_name);if (message_str) {(*jni)->ReleaseStringUTFChars(jni, message_str, message);}
}
JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {jint result;jvmtiCapabilities capabilities;jvmtiEventCallbacks callbacks;result = (*vm)->GetEnv(vm, (void**)&jvmti, JVMTI_VERSION_1_2);if (result != JNI_OK || jvmti == NULL) return JNI_ERR;memset(&capabilities, 0, sizeof(capabilities));capabilities.can_generate_exception_events = 1;result = (*jvmti)->AddCapabilities(jvmti, &capabilities);if (result != JVMTI_ERROR_NONE) {printf("无法设置异常监控能力,错误码: %d\n", result);return JNI_ERR;}memset(&callbacks, 0, sizeof(callbacks));callbacks.ExceptionCatch = &ExceptionCatch;result = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));if (result != JVMTI_ERROR_NONE) return JNI_ERR;(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL);printf("异常跟踪代理初始化成功\n");return JNI_OK;
}JNIEXPORT void JNICALL Agent_OnUnload(JavaVM* vm) {if (jvmti != NULL) {(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_DISABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL);}
}
object_trace_agent.c
#include <jni.h>
#include <jvmti.h>
#include <stdio.h>
#include <string.h>static jvmtiEnv* jvmti = NULL;
void JNICALL VMObjectAlloc(jvmtiEnv* jvmti, JNIEnv* jni, jthread thread,jobject obj, jclass cls, jlong size) {char* class_name;(*jvmti)->GetClassSignature(jvmti, cls, &class_name, NULL);if (class_name) {printf("[ALLOC] 类: %s, 大小: %ld bytes\n", class_name, size);(*jvmti)->Deallocate(jvmti, (unsigned char*)class_name);}
}
JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* vm, char* options, void* reserved) {jint result;jvmtiCapabilities capabilities;jvmtiEventCallbacks callbacks;result = (*vm)->GetEnv(vm, (void**)&jvmti, JVMTI_VERSION_1_2);if (result != JNI_OK || jvmti == NULL) {printf("无法获取JVM TI环境\n");return JNI_ERR;}memset(&capabilities, 0, sizeof(capabilities));capabilities.can_generate_vm_object_alloc_events = 1;result = (*jvmti)->AddCapabilities(jvmti, &capabilities);if (result != JVMTI_ERROR_NONE) {printf("无法设置能力\n");return JNI_ERR;}memset(&callbacks, 0, sizeof(callbacks));callbacks.VMObjectAlloc = &VMObjectAlloc;result = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));if (result != JVMTI_ERROR_NONE) {printf("无法设置回调\n");return JNI_ERR;}result = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,JVMTI_EVENT_VM_OBJECT_ALLOC, NULL);if (result != JVMTI_ERROR_NONE) {printf("无法启用事件\n");return JNI_ERR;}printf("对象跟踪代理初始化成功\n");return JNI_OK;
}JNIEXPORT void JNICALL Agent_OnUnload(JavaVM* vm) {if (jvmti != NULL) {(*jvmti)->SetEventNotificationMode(jvmti, JVMTI_DISABLE,JVMTI_EVENT_VM_OBJECT_ALLOC, NULL);}
}
gbuild.sh
set -xeexport JAVA_INCLUDE_DIR=/etc/alternatives/java_sdk_24gcc -shared -fPIC -shared -I$JAVA_INCLUDE_DIR/include -I$JAVA_INCLUDE_DIR/include/linux $1 -o lib$1.sojava -agentpath:./lib$1.so $2
usage
bash gbuild.sh <what agent.c> <what test java>
JVMTITest.java
public class JVMTITest {static class InnerClass {public void doSomething() {System.out.println("内部类方法被调用");}}public static void main(String[] args) {System.out.println("主程序开始运行");InnerClass inner = new InnerClass();inner.doSomething();try {Class<?> stringClass = Class.forName("java.lang.String");System.out.println("加载了标准类: " + stringClass.getName());} catch (ClassNotFoundException e) {e.printStackTrace();}System.out.println("主程序运行结束");try {throw new Exception("damn");} catch (Exception e) {System.out.println(e.getMessage());}}
}
sample.log
- https://gitee.com/EEPPEE_admin/jvm-backend-example/blob/jni-and-hack-jvm/hackjvm_example/sample.log