Java 通过JVMTI识别异常_Java_Exception_Jvmti

Java 通过JVMTI识别异常

java exception

Java 通过JVMTI识别异常,java,exception,jvmti,Java,Exception,Jvmti,我正在使用JVMTI为Java应用程序编写一个检测工具。我已经看到，JVMTI可以检测何时抛出了异常，何时捕获了异常。本文档说明了事件异常和异常批次异常字段标识抛出的异常对象尽管它没有说明如何在运行期间比较它们（即，比较exception中提供的异常与ExceptionCatch中捕获的表达式相对应）。换句话说，对于 # java -version java version "1.7.0_85" OpenJDK Runtime Environment (IcedTea 2.6.1) (7u

我正在使用JVMTI为Java应用程序编写一个检测工具。我已经看到，JVMTI可以检测何时抛出了异常，何时捕获了异常。本文档说明了事件异常和异常批次

异常字段标识抛出的异常对象

尽管它没有说明如何在运行期间比较它们（即，比较exception中提供的异常与ExceptionCatch中捕获的表达式相对应）。换句话说，对于

# java -version
java version "1.7.0_85"
OpenJDK Runtime Environment (IcedTea 2.6.1) (7u85-2.6.1-5ubuntu0.14.04.1)
OpenJDK 64-Bit Server VM (build 24.85-b03, mixed mode)

当直接比较jexception/jobject时，它似乎并不总是正确的。考虑监视异常和异常捕获事件的JVMTI代理（下面的源代码），还考虑引发异常的后续java天真示例（源代码也包括），最后您可以通过代理与“给定的MaFIX文件”（包括在最末尾）一起使用“运行运行”来运行示例。p> 如果我使用OpenJDK 7运行该示例，它会给出以下结果：

# make run
...
cb_Exception (exception=0x2ae6b8087be8)
cb_ExceptionCatch (exception=0x2ae6b80859f8 vs last_exception=0x2ae6b8087be8)
AreSameObject? = 0
cb_Exception (exception=0x2ae6b80859f8)
cb_ExceptionCatch (exception=0x2ae6b807a388 vs last_exception=0x2ae6b80859f8)
AreSameObject? = 0
cb_Exception (exception=0x2ae6b807a388)
cb_ExceptionCatch (exception=0x2ae6b807a388 vs last_exception=0x2ae6b807a388)
AreSameObject? = 1
cb_Exception (exception=0x2ae6b807a388)
cb_ExceptionCatch (exception=0x2ae6b8078108 vs last_exception=0x2ae6b807a388)
AreSameObject? = 0
cb_Exception (exception=0x2ae6b8078108)
cb_ExceptionCatch (exception=0x2ae6b8078108 vs last_exception=0x2ae6b8078108)
AreSameObject? = 1
cb_Exception (exception=0x2ae6b8078108)
cb_ExceptionCatch (exception=0x2ae6b8078108 vs last_exception=0x2ae6b8078108)
AreSameObject? = 1
before doing work
cb_Exception (exception=0x2ae6b8078108)
cb_ExceptionCatch (exception=0x2ae6b8078108 vs last_exception=0x2ae6b8078108)
AreSameObject? = 1
after doing work

如果我使用IBM的Java1.7.0运行这个示例，情况就有点类似

# make run
...
cb_Exception (exception=0x7d78a0)
cb_ExceptionCatch (exception=0x7d7950 vs last_exception=0x7d78a0)
AreSameObject? = 1
cb_Exception (exception=0x7d7938)
cb_ExceptionCatch (exception=0x7d7950 vs last_exception=0x7d7938)
AreSameObject? = 0
cb_Exception (exception=0x7d7938)
cb_ExceptionCatch (exception=0x7d79a8 vs last_exception=0x7d7938)
AreSameObject? = 1
before doing work
cb_Exception (exception=0x7d7a60)
cb_ExceptionCatch (exception=0x7d7a98 vs last_exception=0x7d7a60)
AreSameObject? = 0
after doing work

在OpenJDK中，请注意每个异常都有一个对应的ExceptionCatch，但是在主Java代码之外有六个异常，我怀疑它们来自Java VM本身。请注意，exception的值在每一对中都不相同。在第5次回调调用之后，exception的值似乎变为常量。IBM的Java中的情况有些类似，但引发的异常较少。根据Chen Harel在评论中的建议，我存储了引发的异常，并通过IsSameObject JNI的方法将其与捕获的异常进行了比较，但JNI声称这些异常并不相同

那么，在应用程序生命周期中，可以通过Exception和ExceptionCatch识别异常吗？如果是这样，通过JVMTI或JNI比较异常的合适方法是什么

agent.c

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

#include <jni.h>
#include <jvmti.h>

#define CHECK_JVMTI_ERROR(x,call) \
    { if (x != JVMTI_ERROR_NONE) { fprintf (stderr, "Error during %s in %s:%d\n", #call, __FILE__, __LINE__); } }

/* Global static data */
static jvmtiEnv     *jvmti;
static jrawMonitorID ExtraeJ_AgentLock;

jobject last_exception;

static void JNICALL cb_Exception (jvmtiEnv *jvmti_env, JNIEnv* jni_env,
    jthread thread, jmethodID method, jlocation location, jobject exception,
    jmethodID catch_method, jlocation catch_location)
{
    printf ("cb_Exception (exception=%p)\n", exception);

    last_exception = exception;
}

static void JNICALL cb_ExceptionCatch (jvmtiEnv *jvmti_env,
    JNIEnv* jni_env, jthread thread, jmethodID method, jlocation location,
    jobject exception)
{
    printf ("cb_ExceptionCatch (exception=%p vs last_exception=%p)\n"
      "AreSameObject? = %d\n",
      exception,
      last_exception,
      (*jni_env)->IsSameObject(jni_env, exception, last_exception));
}

JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved)
{
    jint                rc;
    jvmtiError          r;
    jvmtiCapabilities   capabilities;
    jvmtiEventCallbacks callbacks;

    /* Get JVMTI environment */
    rc = (*vm)->GetEnv(vm, (void **)&jvmti, JVMTI_VERSION);
    if (rc != JNI_OK)
    {
        fprintf (stderr, "Error!: Unable to create jvmtiEnv, rc=%d\n", rc);
        return -1;
    }

    /* Get/Add JVMTI capabilities */
    memset(&capabilities, 0, sizeof(capabilities));
    capabilities.can_generate_exception_events = 1;
    r = (*jvmti)->AddCapabilities(jvmti, &capabilities);
    CHECK_JVMTI_ERROR(r, AddCapabilities);

    /* Set callbacks and enable event notifications */
    memset(&callbacks, 0, sizeof(callbacks));
    callbacks.Exception               = &cb_Exception;
    callbacks.ExceptionCatch          = &cb_ExceptionCatch;
    r = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));
    CHECK_JVMTI_ERROR(r, SetEventCallbacks);

    /* Exception events */
    r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, 
      JVMTI_EVENT_EXCEPTION, NULL);
    CHECK_JVMTI_ERROR(r, SetEventNotificationMode);
    r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, 
      JVMTI_EVENT_EXCEPTION_CATCH, NULL);
    CHECK_JVMTI_ERROR(r, SetEventNotificationMode);

    return 0;
}

JNIEXPORT void JNICALL Agent_OnUnload(JavaVM *vm)
{
}

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

#include <jni.h>
#include <jvmti.h>

#define CHECK_JVMTI_ERROR(x,call) \
    { if (x != JVMTI_ERROR_NONE) { fprintf (stderr, "Error during %s in %s:%d\n", #call, __FILE__, __LINE__); } }

/* Global static data */
static jvmtiEnv     *jvmti;
static jrawMonitorID ExtraeJ_AgentLock;

jobject last_exception;

static void JNICALL cb_Exception (jvmtiEnv *jvmti_env, JNIEnv* jni_env,
    jthread thread, jmethodID method, jlocation location, jobject exception,
    jmethodID catch_method, jlocation catch_location)
{
    printf ("cb_Exception (exception=%p)\n", exception);

    last_exception = (*jni_env)->NewGlobalRef (jni_env, exception);
}

static void JNICALL cb_ExceptionCatch (jvmtiEnv *jvmti_env,
    JNIEnv* jni_env, jthread thread, jmethodID method, jlocation location,
    jobject exception)
{
    printf ("cb_ExceptionCatch (exception=%p vs last_exception=%p)\n"
      "AreSameObject? = %d\n",
      exception,
      last_exception,
      (*jni_env)->IsSameObject(jni_env, exception, last_exception));

    (*jni_env)->DeleteGlobalRef(jni_env, last_exception);
}

JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved)
{
    jint                rc;
    jvmtiError          r;
    jvmtiCapabilities   capabilities;
    jvmtiEventCallbacks callbacks;

    /* Get JVMTI environment */
    rc = (*vm)->GetEnv(vm, (void **)&jvmti, JVMTI_VERSION);
    if (rc != JNI_OK)
    {
        fprintf (stderr, "Error!: Unable to create jvmtiEnv, rc=%d\n", rc);
        return -1;
    }

    /* Get/Add JVMTI capabilities */
    memset(&capabilities, 0, sizeof(capabilities));
    capabilities.can_generate_exception_events = 1;
    r = (*jvmti)->AddCapabilities(jvmti, &capabilities);
    CHECK_JVMTI_ERROR(r, AddCapabilities);

    /* Set callbacks and enable event notifications */
    memset(&callbacks, 0, sizeof(callbacks));
    callbacks.Exception               = &cb_Exception;
    callbacks.ExceptionCatch          = &cb_ExceptionCatch;
    r = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));
    CHECK_JVMTI_ERROR(r, SetEventCallbacks);

    /* Exception events */
    r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, 
      JVMTI_EVENT_EXCEPTION, NULL);
    CHECK_JVMTI_ERROR(r, SetEventNotificationMode);
    r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, 
      JVMTI_EVENT_EXCEPTION_CATCH, NULL);
    CHECK_JVMTI_ERROR(r, SetEventNotificationMode);

    return 0;
}

JNIEXPORT void JNICALL Agent_OnUnload(JavaVM *vm)
{
}

Makefile

JAVA_JDK=/usr/lib/jvm/java-7-openjdk-amd64

all: libagent.so example.class

libagent.so: agent.c
    gcc -shared -fPIC -DPIC agent.c -o libagent.so -I$(JAVA_JDK)/include

example.class: example.java
    javac example.java

run: libagent.so example.class
    java -agentpath:$(PWD)/libagent.so example

11月9日更新
正如Chen Harel所建议的，我已经创建了一个对异常的全局引用。agent.c的修改版本如下所示，执行的输出如下所示
agent.c

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <jni.h> #include <jvmti.h> #define CHECK_JVMTI_ERROR(x,call) \ { if (x != JVMTI_ERROR_NONE) { fprintf (stderr, "Error during %s in %s:%d\n", #call, __FILE__, __LINE__); } } /* Global static data */ static jvmtiEnv *jvmti; static jrawMonitorID ExtraeJ_AgentLock; jobject last_exception; static void JNICALL cb_Exception (jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread, jmethodID method, jlocation location, jobject exception, jmethodID catch_method, jlocation catch_location) { printf ("cb_Exception (exception=%p)\n", exception); last_exception = exception; } static void JNICALL cb_ExceptionCatch (jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread, jmethodID method, jlocation location, jobject exception) { printf ("cb_ExceptionCatch (exception=%p vs last_exception=%p)\n" "AreSameObject? = %d\n", exception, last_exception, (*jni_env)->IsSameObject(jni_env, exception, last_exception)); } JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) { jint rc; jvmtiError r; jvmtiCapabilities capabilities; jvmtiEventCallbacks callbacks; /* Get JVMTI environment */ rc = (*vm)->GetEnv(vm, (void **)&jvmti, JVMTI_VERSION); if (rc != JNI_OK) { fprintf (stderr, "Error!: Unable to create jvmtiEnv, rc=%d\n", rc); return -1; } /* Get/Add JVMTI capabilities */ memset(&capabilities, 0, sizeof(capabilities)); capabilities.can_generate_exception_events = 1; r = (*jvmti)->AddCapabilities(jvmti, &capabilities); CHECK_JVMTI_ERROR(r, AddCapabilities); /* Set callbacks and enable event notifications */ memset(&callbacks, 0, sizeof(callbacks)); callbacks.Exception = &cb_Exception; callbacks.ExceptionCatch = &cb_ExceptionCatch; r = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks)); CHECK_JVMTI_ERROR(r, SetEventCallbacks); /* Exception events */ r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL); CHECK_JVMTI_ERROR(r, SetEventNotificationMode); r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL); CHECK_JVMTI_ERROR(r, SetEventNotificationMode); return 0; } JNIEXPORT void JNICALL Agent_OnUnload(JavaVM *vm) { }

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <jni.h> #include <jvmti.h> #define CHECK_JVMTI_ERROR(x,call) \ { if (x != JVMTI_ERROR_NONE) { fprintf (stderr, "Error during %s in %s:%d\n", #call, __FILE__, __LINE__); } } /* Global static data */ static jvmtiEnv *jvmti; static jrawMonitorID ExtraeJ_AgentLock; jobject last_exception; static void JNICALL cb_Exception (jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread, jmethodID method, jlocation location, jobject exception, jmethodID catch_method, jlocation catch_location) { printf ("cb_Exception (exception=%p)\n", exception); last_exception = (*jni_env)->NewGlobalRef (jni_env, exception); } static void JNICALL cb_ExceptionCatch (jvmtiEnv *jvmti_env, JNIEnv* jni_env, jthread thread, jmethodID method, jlocation location, jobject exception) { printf ("cb_ExceptionCatch (exception=%p vs last_exception=%p)\n" "AreSameObject? = %d\n", exception, last_exception, (*jni_env)->IsSameObject(jni_env, exception, last_exception)); (*jni_env)->DeleteGlobalRef(jni_env, last_exception); } JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM *vm, char *options, void *reserved) { jint rc; jvmtiError r; jvmtiCapabilities capabilities; jvmtiEventCallbacks callbacks; /* Get JVMTI environment */ rc = (*vm)->GetEnv(vm, (void **)&jvmti, JVMTI_VERSION); if (rc != JNI_OK) { fprintf (stderr, "Error!: Unable to create jvmtiEnv, rc=%d\n", rc); return -1; } /* Get/Add JVMTI capabilities */ memset(&capabilities, 0, sizeof(capabilities)); capabilities.can_generate_exception_events = 1; r = (*jvmti)->AddCapabilities(jvmti, &capabilities); CHECK_JVMTI_ERROR(r, AddCapabilities); /* Set callbacks and enable event notifications */ memset(&callbacks, 0, sizeof(callbacks)); callbacks.Exception = &cb_Exception; callbacks.ExceptionCatch = &cb_ExceptionCatch; r = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks)); CHECK_JVMTI_ERROR(r, SetEventCallbacks); /* Exception events */ r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION, NULL); CHECK_JVMTI_ERROR(r, SetEventNotificationMode); r = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_EXCEPTION_CATCH, NULL); CHECK_JVMTI_ERROR(r, SetEventNotificationMode); return 0; } JNIEXPORT void JNICALL Agent_OnUnload(JavaVM *vm) { }

JOBECT是C++指针，对堆的引用在它下面处理。如果你仔细想想，这更像是指向一个指针的指针
测试两个作业对象是否相同的方法是使用jni方法
如果要测试异常的类型，请使用GetObjectClass+IsInstanceOf
编辑

请注意，为了使jobject在方法之间保持有效，您必须使用jni NewGlobalRef方法为它们创建一个引用。
Chen，我更新了我的示例，将抛出的异常存储到一个全局变量中，然后将捕获的异常与此全局变量进行比较。然而，结果似乎并不令人满意，因为例外情况并不匹配。此外，我在IBM的Java 1.7.0上对此进行了测试，结果有些相似。在jni NewGlobalRef上简洁地编辑答案以创建可重用的jobject有趣的是，NewGlobalRef的使用在IBM的Java 1.7.0中起作用。但是，OpenJDK 7中的情况并没有改善，有几个例外不匹配。我已经用全局引用的创建（和删除）更新了agent.c。我还发布了执行结果。嗨，Harald，我正试图编写一个与您类似的代理，但不幸的是，我在findClass和loadClass中遇到异常，我知道它们可能是由于NoClassDefFoundException引起的，但我在包含类文件的同一目录下运行java程序，有什么想法吗？