vmtool lib support reload/reattach.

arthas-vmtool/pom.xml

@@ -121,7 +121,7 @@
                         <linkerStartOption>-o</linkerStartOption>
                     </linkerStartOptions>
                     <linkerEndOptions>
-                        <linkerEndOption>-o ${project.build.directory}/classes/${lib_name}</linkerEndOption>
+                        <linkerEndOption>-o ${project.build.directory}/${lib_name}</linkerEndOption>
                     </linkerEndOptions>
                 </configuration>
                 <executions>

arthas-vmtool/src/main/java/arthas/VmTool.java

@@ -36,11 +36,6 @@ public class VmTool implements VmToolMXBean {
         return instance;
     }
 
-    /**
-     * 检测jni-lib是否正常，如果正常，应该输出OK
-     */
-    private static native String check0();
-
     private static synchronized native void forceGc0();
 
     /**

arthas-vmtool/src/main/java/arthas/package-info.java

@@ -1,6 +1,2 @@
-/**
+
- * <pre>
- * 修改后要同步到 spy/src/main/java 。
- * </pre>
- */
 package arthas;

arthas-vmtool/src/test/java/arthas/VmToolTest.java

@@ -10,12 +10,16 @@ import org.junit.Test;
 
 import com.taobao.arthas.common.VmToolUtils;
 
-import arthas.VmToolTest.LimitTest;
-
 /**
  * 以下本地测试的jvm参数均为：-Xms128m -Xmx128m
  */
 public class VmToolTest {
+    private VmTool initVmTool() {
+        File path = new File(VmTool.class.getProtectionDomain().getCodeSource().getLocation().getPath()).getParentFile();
+
+        String libPath = new File(path, VmToolUtils.detectLibName()).getAbsolutePath();
+        return VmTool.getInstance(libPath);
+    }
 
     /**
      * macbook上运行结果如下
@@ -57,14 +61,6 @@ public class VmToolTest {
         }
     }
 
-    private VmTool initVmTool() {
-        String path = VmTool.class.getProtectionDomain().getCodeSource().getLocation().getPath();
-        System.err.println(path);
-
-        String libPath = new File(path, VmToolUtils.detectLibName()).getAbsolutePath();
-        return VmTool.getInstance(libPath);
-    }
-
     @Test
     public void testGetInstancesMemoryLeak() {
         //这里睡20s是为了方便用jprofiler连接上进程

core/pom.xml

@@ -120,6 +120,11 @@
             <artifactId>arthas-common</artifactId>
             <version>${project.version}</version>
         </dependency>
+        <dependency>
+            <groupId>com.taobao.arthas</groupId>
+            <artifactId>arthas-vmtool</artifactId>
+            <version>${project.version}</version>
+        </dependency>
         <dependency>
             <groupId>com.alibaba</groupId>
             <artifactId>bytekit-core</artifactId>

core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java

@@ -1,6 +1,8 @@
 package com.taobao.arthas.core.command.monitor200;
 
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
 import java.lang.instrument.Instrumentation;
 import java.security.CodeSource;
 import java.util.ArrayList;
@@ -11,6 +13,7 @@ import java.util.Set;
 
 import com.alibaba.arthas.deps.org.slf4j.Logger;
 import com.alibaba.arthas.deps.org.slf4j.LoggerFactory;
+import com.taobao.arthas.common.IOUtils;
 import com.taobao.arthas.common.VmToolUtils;
 import com.taobao.arthas.core.command.Constants;
 import com.taobao.arthas.core.command.express.Express;
@@ -246,6 +249,25 @@ public class VmToolCommand extends AnnotatedCommand {
             if (libPath == null) {
                 libPath = defaultLibPath;
             }
+
+            // 尝试把lib文件复制到临时文件里，避免多次attach时出现 Native Library already loaded in another classloader
+            FileOutputStream tmpLibOutputStream = null;
+            FileInputStream libInputStream = null;
+            try {
+                File tmpLibFile = File.createTempFile(VmTool.JNI_LIBRARY_NAME, null);
+                tmpLibOutputStream = new FileOutputStream(tmpLibFile);
+                libInputStream = new FileInputStream(new File(libPath));
+
+                IOUtils.copy(libInputStream, tmpLibOutputStream);
+                libPath = tmpLibFile.getAbsolutePath();
+                logger.debug("copy {} to {}", libPath, tmpLibFile);
+            } catch (Throwable e) {
+                logger.error("try to copy lib error! libPath: {}", libPath, e);
+            } finally {
+                IOUtils.close(libInputStream);
+                IOUtils.close(tmpLibOutputStream);
+            }
+
             vmTool = VmTool.getInstance(libPath);
         }
         return vmTool;

spy/src/main/java/arthas/VmTool.java

@@ -1,111 +0,0 @@
-package arthas;
-
-/**
- * @author ZhangZiCheng 2021-02-12
- * @author hengyunabc 2021-04-26
- * @since 3.5.1
- */
-public class VmTool implements VmToolMXBean {
-
-    /**
-     * 不要修改jni-lib的名称
-     */
-    public final static String JNI_LIBRARY_NAME = "ArthasJniLibrary";
-
-    private static VmTool instance;
-
-    private VmTool() {
-    }
-
-    public static VmTool getInstance() {
-        return getInstance(null);
-    }
-
-    public static synchronized VmTool getInstance(String libPath) {
-        if (instance != null) {
-            return instance;
-        }
-
-        if (libPath == null) {
-            System.loadLibrary(JNI_LIBRARY_NAME);
-        } else {
-            System.load(libPath);
-        }
-
-        instance = new VmTool();
-        return instance;
-    }
-
-    /**
-     * 检测jni-lib是否正常，如果正常，应该输出OK
-     */
-    private static native String check0();
-
-    private static synchronized native void forceGc0();
-
-    /**
-     * 获取某个class在jvm中当前所有存活实例
-     */
-    private static synchronized native <T> T[] getInstances0(Class<T> klass, int limit);
-
-    /**
-     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
-     */
-    private static synchronized native long sumInstanceSize0(Class<?> klass);
-
-    /**
-     * 获取某个实例的占用内存，单位：Byte
-     */
-    private static native long getInstanceSize0(Object instance);
-
-    /**
-     * 统计某个class在jvm中当前所有存活实例的总个数
-     */
-    private static synchronized native long countInstances0(Class<?> klass);
-
-    /**
-     * 获取所有已加载的类
-     * @param klass 这个参数必须是 Class.class
-     * @return
-     */
-    private static synchronized native Class<?>[] getAllLoadedClasses0(Class<?> klass);
-
-    @Override
-    public void forceGc() {
-        forceGc0();
-    }
-
-    @Override
-    public <T> T[] getInstances(Class<T> klass) {
-        return getInstances0(klass, -1);
-    }
-
-    @Override
-    public <T> T[] getInstances(Class<T> klass, int limit) {
-        if (limit == 0) {
-            throw new IllegalArgumentException("limit can not be 0");
-        }
-        return getInstances0(klass, limit);
-    }
-
-    @Override
-    public long sumInstanceSize(Class<?> klass) {
-        return sumInstanceSize0(klass);
-    }
-
-    @Override
-    public long getInstanceSize(Object instance) {
-        return getInstanceSize0(instance);
-    }
-
-    @Override
-    public long countInstances(Class<?> klass) {
-        return countInstances0(klass);
-    }
-
-    @Override
-    public Class<?>[] getAllLoadedClasses() {
-        return getAllLoadedClasses0(Class.class);
-    }
-
-}

spy/src/main/java/arthas/VmToolMXBean.java

@@ -1,53 +0,0 @@
-package arthas;
-
-/**
- * VmTool interface for JMX server. How to register VmTool MBean:
- *
- * <pre>
- * {@code
- *     ManagementFactory.getPlatformMBeanServer().registerMBean(
- *             VmTool.getInstance(),
- *             new ObjectName("arthas:type=VmTool")
- *     );
- * }
- * </pre>
- * @author hengyunabc 2021-04-26
- */
-public interface VmToolMXBean {
-
-    /**
-     * https://docs.oracle.com/javase/8/docs/platform/jvmti/jvmti.html#ForceGarbageCollection
-     */
-    public void forceGc();
-
-    public <T> T[] getInstances(Class<T> klass);
-
-    /**
-     * 获取某个class在jvm中当前所有存活实例
-     * @param <T>
-     * @param klass
-     * @param limit 如果小于 0 ，则不限制
-     * @return
-     */
-    public <T> T[] getInstances(Class<T> klass, int limit);
-
-    /**
-     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
-     */
-    public long sumInstanceSize(Class<?> klass);
-
-    /**
-     * 获取某个实例的占用内存，单位：Byte
-     */
-    public long getInstanceSize(Object instance);
-
-    /**
-     * 统计某个class在jvm中当前所有存活实例的总个数
-     */
-    public long countInstances(Class<?> klass);
-
-    /**
-     * 获取所有已加载的类
-     */
-    public Class<?>[] getAllLoadedClasses();
-}

spy/src/main/java/arthas/package-info.java

@@ -1,8 +0,0 @@
-/**
- * <pre>
- * copy from arthas-vmtool/src/main/java 。
- * 因为动态链接库只能被加载一次，只能使用一份代码。放在spy jar里保证只有一份。
- * TODO 当arthas本身版本升级时，已append 到bootstrap classloader的spy jar不能升级，VmTool的接口可以会调用失败。
- * </pre>
- */
-package arthas;