Ensure all code runs in "empty" classloader.

Hide JGrab's classes. Better error handling.
renatoathaydes · Apr 25, 2024 · b22586f · b22586f
1 parent 323b667
commit b22586f
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Showing 5 changed files with 54 additions and 22 deletions.
diff --git a/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/EmptyClassLoaderContext.java b/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/EmptyClassLoaderContext.java
@@ -0,0 +1,20 @@
+package com.athaydes.jgrab.runner;
+
+import com.athaydes.osgiaas.api.env.ClassLoaderContext;
+
+import java.util.Collection;
+import java.util.List;
+
+enum EmptyClassLoaderContext implements ClassLoaderContext {
+    INSTANCE;
+
+    @Override
+    public ClassLoader getClassLoader() {
+        return ClassLoader.getPlatformClassLoader();
+    }
+
+    @Override
+    public Collection<String> getClassesIn( String s ) {
+        return List.of();
+    }
+}
diff --git a/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/JGrabClassLoaderContext.java b/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/JGrabClassLoaderContext.java
@@ -7,11 +7,7 @@
 import java.io.IOException;
 import java.net.URL;
 import java.net.URLClassLoader;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Enumeration;
-import java.util.List;
+import java.util.*;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
 import java.util.stream.Collectors;
@@ -30,7 +26,7 @@ class JGrabClassLoaderContext implements ClassLoaderContext {
         URL[] jarUrls = new URL[ dependencyJars.size() ];
         this.jars = new ArrayList<>( dependencyJars.size() );
 
-        for (int i = 0; i < dependencyJars.size(); i++) {
+        for ( int i = 0; i < dependencyJars.size(); i++ ) {
             File jar = dependencyJars.get( i );
 
             try {
@@ -41,7 +37,7 @@ class JGrabClassLoaderContext implements ClassLoaderContext {
             }
         }
 
-        this.dependenciesClassLoader = new URLClassLoader( jarUrls );
+        this.dependenciesClassLoader = new URLClassLoader( jarUrls, ClassLoader.getPlatformClassLoader() );
     }
 
     @Override

diff --git a/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/JGrabError.java b/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/JGrabError.java
@@ -8,4 +8,8 @@ public class JGrabError extends RuntimeException {
     public JGrabError( String message ) {
         super( message );
     }
+
+    public JGrabError( Throwable cause ) {
+        super( cause );
+    }
 }
diff --git a/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/JGrabRunner.java b/jgrab-runner/src/main/java/com/athaydes/jgrab/runner/JGrabRunner.java
@@ -7,7 +7,6 @@
 import com.athaydes.jgrab.daemon.JGrabDaemon;
 import com.athaydes.jgrab.jbuild.JBuildGrabber;
 import com.athaydes.osgiaas.api.env.ClassLoaderContext;
-import com.athaydes.osgiaas.javac.internal.DefaultClassLoaderContext;
 import com.athaydes.osgiaas.javac.internal.compiler.OsgiaasJavaCompilerService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -120,7 +119,7 @@ public static void populateClassLoaderCache( Collection<Classpath> classpaths )
 
     private static ClassLoaderContext classLoaderFor( Classpath classpath ) {
         if ( classpath.isEmpty() ) {
-            return DefaultClassLoaderContext.INSTANCE;
+            return EmptyClassLoaderContext.INSTANCE;
         }
         return classLoaderCache.computeIfAbsent( classpath.hash, ignore ->
                 new JGrabClassLoaderContext( classpath.resolvedArtifacts ) );
@@ -153,8 +152,7 @@ private static void runJavaSnippet( String snippet, ClassLoaderContext classLoad
                 System.out.println( result );
             }
         } catch ( Throwable t ) {
-            System.err.println( "Problem running Java snippet: " + t );
-            t.printStackTrace();
+            throw new JGrabError( t );
         }
     }
 
@@ -172,16 +170,14 @@ private static void runJavaClass( JavaCode javaCode,
                 Runnable runnable = ( Runnable ) compiledClass.getDeclaredConstructor().newInstance();
                 runnable.run();
             } catch ( Throwable t ) {
-                System.err.println( "Problem running Java class: " + t );
-                t.printStackTrace();
+                throw new JGrabError( t );
             }
         } else {
             try {
                 Method method = compiledClass.getMethod( "main", String[].class );
                 method.invoke( compiledClass, ( Object ) args );
             } catch ( Throwable t ) {
-                System.err.println( "Problem running Java class: " + t );
-                t.printStackTrace();
+                throw new JGrabError( t );
             }
         }
     }
@@ -201,11 +197,14 @@ private static void run( String currentDir, String[] args ) {
                 run( currentDir, options );
             }
         } catch ( JGrabError e ) {
-            System.err.println( e.getMessage() );
+            if ( e.getMessage() != null ) {
+                logger.error( "{}", e.getMessage() );
+            } else {
+                logger.error( "JGrab Error", e.getCause() );
+            }
             System.exit( 1 );
         } catch ( Exception e ) {
-            System.err.println( "Unable to run Java class due to " + e );
-            e.printStackTrace();
+            logger.error( "Unexpected Error", e );
             System.exit( 2 );
         }
     }

diff --git a/jgrab-test/src/test/java/com/athaydes/jgrab/test/JGrabTest.java b/jgrab-test/src/test/java/com/athaydes/jgrab/test/JGrabTest.java
@@ -7,6 +7,7 @@
 
 import static com.athaydes.jgrab.test.JGrabTestRunner.jgrab;
 import static java.util.stream.Collectors.toList;
+import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.startsWith;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertThat;
@@ -32,7 +33,7 @@ public void runRunnableClass() throws Exception {
                         "Ola class jline.console.ConsoleReader" ),
                 result.stdout.lines().collect( toList() ) );
 
-        assertEquals( result.stderr.trim(), "" );
+        assertEquals( "", result.stderr.trim() );
     }
 
     @Test
@@ -44,21 +45,33 @@ public void runScript() throws Exception {
         assertEquals( "Result: " + result,
                 List.of( "5" ),
                 result.stdout.lines().collect( toList() ) );
-        assertEquals( result.stderr.trim(), "" );
+        assertEquals( "", result.stderr.trim() );
     }
 
     @Test
     public void runVersion() throws Exception {
         var result = jgrab( "-v" );
         result.assertOk();
         assertThat( result.stdout, startsWith( "JGrab Version" ) );
-        assertEquals( result.stderr.trim(), "" );
+        assertEquals( "", result.stderr.trim() );
     }
 
     @Test
     public void unknownOption() throws Exception {
         var result = jgrab( "-f" );
         result.assertCode( 1 );
-        assertEquals( result.stderr.trim(), "Unknown option: -f" );
+        assertEquals( "[main] ERROR com.athaydes.jgrab.runner.JGrabRunner - " +
+                "Unknown option: -f", result.stderr.trim() );
+    }
+
+    @Test
+    public void codeCannotSeeJGrabClasses() throws Exception {
+        var result = jgrab( "-e", "com.athaydes.jgrab.runner.JGrabRunner.class" );
+        result.assertCode( 1 );
+        assertThat( result.stderr.trim(),
+                containsString(
+                        "java.lang.NoClassDefFoundError: " +
+                                "com/athaydes/jgrab/runner/JGrabRunner" ) );
+        assertEquals( "", result.stdout.trim() );
     }
 }