fix logger command print parent ClassLoader result problem. #870

core/src/main/java/com/taobao/arthas/core/command/logger/AsmRenameUtil.java

@@ -0,0 +1,43 @@
+package com.taobao.arthas.core.command.logger;
+
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.commons.ClassRemapper;
+import org.objectweb.asm.commons.Remapper;
+import org.objectweb.asm.commons.SimpleRemapper;
+
+/**
+ * 
+ * @author hengyunabc 2019-09-23
+ *
+ */
+public class AsmRenameUtil {
+
+    public static byte[] renameClass(byte[] bytes, final String oldName, final String newName) {
+        ClassReader reader = new ClassReader(bytes);
+        ClassWriter writer = new ClassWriter(reader, 0);
+
+        final String internalOldName = oldName.replace('.', '/');
+        final String internalNewName = newName.replace('.', '/');
+//        ClassVisitor visitor = new ClassRemapper(writer, new Remapper() {
+//
+//            @Override
+//            public String mapType(String internalName) {
+//                if (internalName.equals(internalOldName)) {
+//                    return internalNewName;
+//                } else {
+//                    return super.mapType(internalName);
+//                }
+//            }
+//
+//        });
+        
+        ClassVisitor visitor = new ClassRemapper(writer, new SimpleRemapper(internalOldName, internalNewName));
+        
+        
+        reader.accept(visitor, 0);
+        return writer.toByteArray();
+    }
+
+}

core/src/main/java/com/taobao/arthas/core/command/logger/Log4j2Helper.java

@@ -19,6 +19,8 @@ import org.apache.logging.log4j.core.appender.FileAppender;
 import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.config.LoggerConfig;
 
+import com.taobao.arthas.core.util.StringUtils;
+
 /**
  * 
  * @author hengyunabc 2019-09-20
@@ -30,7 +32,7 @@ public class Log4j2Helper {
 
     static {
         try {
-            Class<?> loggerClass = Class.forName("org.apache.logging.log4j.Logger");
+            Class<?> loggerClass = Log4j2Helper.class.getClassLoader().loadClass("org.apache.logging.log4j.Logger");
             // 这里可能会加载到其它上游ClassLoader的log4j2，因此需要判断是否当前classloader
             if (loggerClass.getClassLoader().equals(Log4j2Helper.class.getClassLoader())) {
                 Log4j2 = true;
@@ -93,6 +95,10 @@ public class Log4j2Helper {
             if (loggerConfig == null) {
                 return loggerInfoMap;
             }
+            // 排掉非root时，获取到root的logger config
+            if (!name.equalsIgnoreCase(LoggerConfig.ROOT) && StringUtils.isEmpty(loggerConfig.getName())) {
+                return loggerInfoMap;
+            }
             loggerInfoMap.put(name, doGetLoggerInfo(loggerConfig));
         } else {
             // 获取所有logger时，如果没有appender则忽略

core/src/main/java/com/taobao/arthas/core/command/logger/Log4jHelper.java

@@ -26,7 +26,7 @@ public class Log4jHelper {
 
     static {
         try {
-            Class<?> loggerClass = Class.forName("org.apache.log4j.Logger");
+            Class<?> loggerClass = Log4jHelper.class.getClassLoader().loadClass("org.apache.log4j.Logger");
             // 这里可能会加载到其它上游ClassLoader的log4j，因此需要判断是否当前classloader
             if (loggerClass.getClassLoader().equals(Log4jHelper.class.getClassLoader())) {
                 Log4j = true;
@@ -129,6 +129,10 @@ public class Log4jHelper {
     private static List<Map<String, Object>> doGetLoggerAppenders(Enumeration<Appender> appenders) {
         List<Map<String, Object>> result = new ArrayList<Map<String, Object>>();
 
+        if (appenders == null) {
+            return result;
+        }
+
         while (appenders.hasMoreElements()) {
             Map<String, Object> info = new HashMap<String, Object>();
             Appender appender = appenders.nextElement();
@@ -143,7 +147,9 @@ public class Log4jHelper {
                 info.put(LoggerHelper.target, ((ConsoleAppender) appender).getTarget());
             } else if (appender instanceof AsyncAppender) {
                 @SuppressWarnings("unchecked")
-                List<Map<String, Object>> asyncs = doGetLoggerAppenders(((AsyncAppender) appender).getAllAppenders());
+                Enumeration<Appender> appendersOfAsync = ((AsyncAppender) appender).getAllAppenders();
+                if (appendersOfAsync != null) {
+                    List<Map<String, Object>> asyncs = doGetLoggerAppenders(appendersOfAsync);
                     // 标明异步appender
                     List<String> appenderRef = new ArrayList<String>();
                     for (Map<String, Object> a : asyncs) {
@@ -154,6 +160,7 @@ public class Log4jHelper {
                     info.put(LoggerHelper.appenderRef, appenderRef);
                 }
             }
+        }
 
         return result;
     }

core/src/main/java/com/taobao/arthas/core/command/logger/LogbackHelper.java

@@ -34,7 +34,7 @@ public class LogbackHelper {
 
     static {
         try {
-            Class<?> loggerClass = Class.forName("ch.qos.logback.classic.Logger");
+            Class<?> loggerClass = LogbackHelper.class.getClassLoader().loadClass("ch.qos.logback.classic.Logger");
             // 这里可能会加载到应用中依赖的logback，因此需要判断classloader
             if (loggerClass.getClassLoader().equals(LogbackHelper.class.getClassLoader())) {
                 ILoggerFactory loggerFactory = org.slf4j.LoggerFactory.getILoggerFactory();

core/src/main/java/com/taobao/arthas/core/command/logger/LoggerCommand.java

@@ -41,8 +41,8 @@ import com.taobao.text.util.RenderUtil;
  */
 @Name("logger")
 @Summary("Print logger info, and update the logger level")
-@Description("\nExamples:\n" + "  logger\n" + "  logger -c 327a647b\n" + "  logger -c 327a647b --name ROOT --level debug\n"
+@Description("\nExamples:\n" + "  logger\n" + "  logger -c 327a647b\n"
-                + Constants.WIKI + Constants.WIKI_HOME + "logger")
+                + "  logger -c 327a647b --name ROOT --level debug\n" + Constants.WIKI + Constants.WIKI_HOME + "logger")
 public class LoggerCommand extends AnnotatedCommand {
     private static final Logger logger = LogUtil.getArthasLogger();
 
@@ -53,6 +53,9 @@ public class LoggerCommand extends AnnotatedCommand {
 
     private static Map<Class<?>, byte[]> classToBytesMap = new HashMap<Class<?>, byte[]>();
 
+    private static String arthasClassLoaderHash = ClassLoaderUtils
+                    .classLoaderHash(LoggerCommand.class.getClassLoader());
+
     static {
         LoggerHelperBytes = loadClassBytes(LoggerHelper.class);
         Log4jHelperBytes = loadClassBytes(Log4jHelper.class);
@@ -278,7 +281,8 @@ public class LoggerCommand extends AnnotatedCommand {
                                         label("" + appenderInfo.get(LoggerHelper.target)));
                     }
                     if (appenderInfo.get(LoggerHelper.blocking) != null) {
-                        appendersTable.row(label(LoggerHelper.blocking), label("" + appenderInfo.get(LoggerHelper.blocking)));
+                        appendersTable.row(label(LoggerHelper.blocking),
+                                        label("" + appenderInfo.get(LoggerHelper.blocking)));
                     }
                     if (appenderInfo.get(LoggerHelper.appenderRef) != null) {
                         appendersTable.row(label(LoggerHelper.appenderRef),
@@ -294,21 +298,33 @@ public class LoggerCommand extends AnnotatedCommand {
         return sb.toString();
     }
 
+    private static String helperClassNameWithClassLoader(ClassLoader classLoader, Class<?> helperClass) {
+        String classLoaderHash = ClassLoaderUtils.classLoaderHash(classLoader);
+        String className = helperClass.getName();
+        // if want to debug, change to return className
+        return className + arthasClassLoaderHash + classLoaderHash;
+    }
+
     @SuppressWarnings("unchecked")
     private Map<String, Map<String, Object>> loggerInfo(ClassLoader classLoader, Class<?> helperClass) {
         Map<String, Map<String, Object>> loggers = Collections.emptyMap();
+
+        String helperClassName = helperClassNameWithClassLoader(classLoader, helperClass);
         try {
-            classLoader.loadClass(helperClass.getName());
+            classLoader.loadClass(helperClassName);
         } catch (ClassNotFoundException e) {
             try {
-                ReflectUtils.defineClass(helperClass.getName(), classToBytesMap.get(helperClass), classLoader);
+                byte[] helperClassBytes = AsmRenameUtil.renameClass(classToBytesMap.get(helperClass),
-            } catch (Exception e1) {
+                                helperClass.getName(), helperClassName);
-                // ignore
+                ReflectUtils.defineClass(helperClassName, helperClassBytes, classLoader);
+            } catch (Throwable e1) {
+                logger.error("arthas", "arthas loggger command try to define helper class error: " + helperClassName,
+                                e1);
             }
         }
 
         try {
-            Class<?> clazz = classLoader.loadClass(helperClass.getName());
+            Class<?> clazz = classLoader.loadClass(helperClassName);
             Method getLoggersMethod = clazz.getMethod("getLoggers", new Class<?>[] { String.class, boolean.class });
             loggers = (Map<String, Map<String, Object>>) getLoggersMethod.invoke(null,
                             new Object[] { name, includeNoAppender });
@@ -326,7 +342,7 @@ public class LoggerCommand extends AnnotatedCommand {
             classLoader = ClassLoaderUtils.getClassLoader(inst, hashCode);
         }
 
-        Class<?> clazz = classLoader.loadClass(helperClass.getName());
+        Class<?> clazz = classLoader.loadClass(helperClassNameWithClassLoader(classLoader, helperClass));
         Method updateLevelMethod = clazz.getMethod("updateLevel", new Class<?>[] { String.class, String.class });
         return (Boolean) updateLevelMethod.invoke(null, new Object[] { this.name, this.level });
 

core/src/main/java/com/taobao/arthas/core/util/ClassLoaderUtils.java

@@ -38,4 +38,20 @@ public class ClassLoaderUtils {
         }
         return null;
     }
+
+    public static String classLoaderHash(ClassLoader classLoader) {
+        int hashCode = 0;
+        if (classLoader == null) {
+            hashCode = System.identityHashCode(classLoader);
+        } else {
+            hashCode = classLoader.hashCode();
+        }
+        if (hashCode <= 0) {
+            hashCode = System.identityHashCode(classLoader);
+            if (hashCode < 0) {
+                hashCode = -hashCode;
+            }
+        }
+        return Integer.toHexString(hashCode);
+    }
 }