add ognl command. #240

core/src/main/java/com/taobao/arthas/core/command/BuiltinCommandPack.java

@@ -15,6 +15,7 @@ import com.taobao.arthas.core.command.klass100.ClassLoaderCommand;
 import com.taobao.arthas.core.command.klass100.DumpClassCommand;
 import com.taobao.arthas.core.command.klass100.GetStaticCommand;
 import com.taobao.arthas.core.command.klass100.JadCommand;
+import com.taobao.arthas.core.command.klass100.OgnlCommand;
 import com.taobao.arthas.core.command.klass100.RedefineCommand;
 import com.taobao.arthas.core.command.klass100.SearchClassCommand;
 import com.taobao.arthas.core.command.klass100.SearchMethodCommand;
@@ -66,6 +67,7 @@ public class BuiltinCommandPack implements CommandResolver {
         commands.add(Command.create(TimeTunnelCommand.class));
         commands.add(Command.create(JvmCommand.class));
         // commands.add(Command.create(GroovyScriptCommand.class));
+        commands.add(Command.create(OgnlCommand.class));
         commands.add(Command.create(DashboardCommand.class));
         commands.add(Command.create(DumpClassCommand.class));
         commands.add(Command.create(JulyCommand.class));

core/src/main/java/com/taobao/arthas/core/command/express/ClassLoaderClassResolver.java

@@ -0,0 +1,42 @@
+package com.taobao.arthas.core.command.express;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import ognl.ClassResolver;
+
+/**
+ *
+ * @author hengyunabc 2018-10-18
+ * @see ognl.DefaultClassResolver
+ */
+public class ClassLoaderClassResolver implements ClassResolver {
+
+    private ClassLoader classLoader;
+
+    private Map<String, Class<?>> classes = new ConcurrentHashMap<String, Class<?>>(101);
+
+    public ClassLoaderClassResolver(ClassLoader classLoader) {
+        this.classLoader = classLoader;
+    }
+
+    @Override
+    public Class<?> classForName(String className, @SuppressWarnings("rawtypes") Map context)
+                    throws ClassNotFoundException {
+        Class<?> result = null;
+
+        if ((result = classes.get(className)) == null) {
+            try {
+                result = classLoader.loadClass(className);
+            } catch (ClassNotFoundException ex) {
+                if (className.indexOf('.') == -1) {
+                    result = Class.forName("java.lang." + className);
+                    classes.put("java.lang." + className, result);
+                }
+            }
+            classes.put(className, result);
+        }
+        return result;
+    }
+
+}

core/src/main/java/com/taobao/arthas/core/command/express/ExpressFactory.java

@@ -23,4 +23,7 @@ public class ExpressFactory {
         return expressRef.get().reset().bind(object);
     }
 
+    public static Express unpooledExpress(ClassLoader classloader) {
+        return new OgnlExpress(new ClassLoaderClassResolver(classloader));
+    }
 }

core/src/main/java/com/taobao/arthas/core/command/express/OgnlExpress.java

@@ -2,12 +2,15 @@ package com.taobao.arthas.core.command.express;
 
 import com.taobao.arthas.core.util.LogUtil;
 import com.taobao.middleware.logger.Logger;
+
+import ognl.ClassResolver;
 import ognl.DefaultMemberAccess;
 import ognl.Ognl;
 import ognl.OgnlContext;
 
 /**
  * @author ralf0131 2017-01-04 14:41.
+ * @author hengyunabc 2018-10-18
  */
 public class OgnlExpress implements Express {
 
@@ -17,14 +20,19 @@ public class OgnlExpress implements Express {
     private final OgnlContext context;
 
     public OgnlExpress() {
+        this(CustomClassResolver.customClassResolver);
+    }
+
+    public OgnlExpress(ClassResolver classResolver) {
         context = new OgnlContext();
-        context.setClassResolver(CustomClassResolver.customClassResolver);
+        context.setClassResolver(classResolver);
+        // allow private field access
+        context.setMemberAccess(new DefaultMemberAccess(true));
     }
 
     @Override
     public Object get(String express) throws ExpressException {
         try {
-            context.setMemberAccess(new DefaultMemberAccess(true));
             return Ognl.getValue(express, context, bindObject);
         } catch (Exception e) {
             logger.error(null, "Error during evaluating the expression:", e);

core/src/main/java/com/taobao/arthas/core/command/klass100/GetStaticCommand.java

@@ -73,7 +73,7 @@ public class GetStaticCommand extends AnnotatedCommand {
 
     @Option(shortName = "c", longName = "classloader")
     @Description("The hash code of the special class's classLoader")
-    public void setCode(String hashCode) {
+    public void setHashCode(String hashCode) {
         this.hashCode = hashCode;
     }
 

core/src/main/java/com/taobao/arthas/core/command/klass100/OgnlCommand.java

@@ -0,0 +1,106 @@
+package com.taobao.arthas.core.command.klass100;
+
+import java.lang.instrument.Instrumentation;
+
+import com.taobao.arthas.core.command.Constants;
+import com.taobao.arthas.core.command.express.Express;
+import com.taobao.arthas.core.command.express.ExpressException;
+import com.taobao.arthas.core.command.express.ExpressFactory;
+import com.taobao.arthas.core.shell.command.AnnotatedCommand;
+import com.taobao.arthas.core.shell.command.CommandProcess;
+import com.taobao.arthas.core.util.LogUtil;
+import com.taobao.arthas.core.util.StringUtils;
+import com.taobao.arthas.core.view.ObjectView;
+import com.taobao.middleware.cli.annotations.Argument;
+import com.taobao.middleware.cli.annotations.Description;
+import com.taobao.middleware.cli.annotations.Name;
+import com.taobao.middleware.cli.annotations.Option;
+import com.taobao.middleware.cli.annotations.Summary;
+import com.taobao.middleware.logger.Logger;
+
+/**
+ *
+ * @author hengyunabc 2018-10-18
+ *
+ */
+@Name("ognl")
+@Summary("Execute ognl expression.")
+@Description(Constants.EXAMPLE
+                + "  ognl '@java.lang.System@out.println(\"hello\")' \n"
+                + "  ognl -x 2 '@Singleton@getInstance() \n"
+                + "  ognl '@Demo@staticFiled' \n"
+                + "  ognl '#value1=@System@getProperty(\"java.home\"), #value2=@System@getProperty(\"java.runtime.name\"), {#value1, #value2}'\n"
+                + "  ognl -c 5d113a51 '@com.taobao.arthas.core.GlobalOptions@isDump' \n"
+                + Constants.WIKI + Constants.WIKI_HOME + "ognl\n"
+                + "  https://commons.apache.org/proper/commons-ognl/language-guide.html")
+public class OgnlCommand extends AnnotatedCommand {
+    private static final Logger logger = LogUtil.getArthasLogger();
+
+    private String express;
+
+    private String hashCode;
+    private int expand = 1;
+
+    @Argument(argName = "express", index = 0, required = true)
+    @Description("The ognl expression.")
+    public void setExpress(String express) {
+        this.express = express;
+    }
+
+    @Option(shortName = "c", longName = "classLoader")
+    @Description("The hash code of the special class's classLoader, default classLoader is SystemClassLoader.")
+    public void setHashCode(String hashCode) {
+        this.hashCode = hashCode;
+    }
+
+    @Option(shortName = "x", longName = "expand")
+    @Description("Expand level of object (1 by default).")
+    public void setExpand(Integer expand) {
+        this.expand = expand;
+    }
+
+    @Override
+    public void process(CommandProcess process) {
+        int exitCode = 0;
+        try {
+            Instrumentation inst = process.session().getInstrumentation();
+            ClassLoader classLoader = null;
+            if (hashCode == null) {
+                classLoader = ClassLoader.getSystemClassLoader();
+            } else {
+                classLoader = findClassLoader(inst, hashCode);
+            }
+
+            if (classLoader == null) {
+                process.write("Can not find classloader with hashCode: " + hashCode + ".\n");
+                exitCode = -1;
+                return;
+            }
+
+            Express unpooledExpress = ExpressFactory.unpooledExpress(classLoader);
+            try {
+                Object value = unpooledExpress.get(express);
+                String result = StringUtils.objectToString(expand >= 0 ? new ObjectView(value, expand).draw() : value);
+                process.write(result + "\n");
+            } catch (ExpressException e) {
+                logger.warn("ognl: failed execute express: " + express, e);
+                process.write("Failed to get static, exception message: " + e.getMessage()
+                                + ", please check $HOME/logs/arthas/arthas.log for more details. \n");
+                exitCode = -1;
+            }
+        } finally {
+            process.end(exitCode);
+        }
+    }
+
+    private static ClassLoader findClassLoader(Instrumentation inst, String hashCode) {
+        for (Class<?> clazz : inst.getAllLoadedClasses()) {
+            ClassLoader classLoader = clazz.getClassLoader();
+            if (classLoader != null && hashCode.equals(Integer.toHexString(classLoader.hashCode()))) {
+                return classLoader;
+            }
+        }
+        return null;
+    }
+
+}