Stop output by default. Update README.

tools/aegis4j/README.md

@@ -1,4 +1,17 @@
-# aegis4j
+# Fork of aegis4j
+
+This module is a fork of [aegis4j](https://github.com/gredler/aegis4j). Many thanks to the oiginal author(s).
+The main changes in this fork are:
+
+- Additional patches for more unused methods and classes tagged as vulnerable in our dependencies.
+- Patches now patch the beginning of a method or constructor body, and don't replace the whole body. This maintains behaviour
+  where an exception is thrown, but allows fixes where appropriate code can be inserted at the start of a method.
+- Compatibility with JDK8
+- Support for specifying different source files or resources for the patches
+- Support for a system property to provide addition in-the-field patches for emergency use
+- Reduced output, except in error conditions.
+
+# Original aegis4j README
 
 Avoid the NEXT Log4Shell vulnerability!
 

tools/aegis4j/build.gradle

@@ -55,6 +55,7 @@ test {
     useJUnitPlatform()
     systemProperty 'jdk.attach.allowAttachSelf', 'true' // tests attach agent to local VM
     systemProperty 'aegis4j.projectDir', "${project.projectDir.toString()}"
+    systemProperty 'aegis4j.log', "true"
     forkEvery 1 // tests cannot undo class modifications to clean up after themselves
     testLogging {
         events 'passed', 'skipped', 'failed'

tools/aegis4j/src/main/java/net/gredler/aegis4j/AegisAgent.java

@@ -26,6 +26,16 @@ import java.util.stream.Collectors;
  */
 public final class AegisAgent {
 
+    public static boolean log = Boolean.getBoolean("aegis4j.log");
+
+    public static void logPrint(String line) {
+        if (log) System.out.print(line);
+    }
+
+    public static void logPrintln(String line) {
+        if (log) System.out.println(line);
+    }
+
     private static Instrumentation instrumentation;
 
     /**
@@ -66,13 +76,13 @@ public final class AegisAgent {
                         }
                         InputStream in = path.toUri().toURL().openStream();
                         props = readPropertiesFromStream(in);
-                        System.out.println("Aegis4j patching from " + path + " mods file");
+                        logPrintln("Aegis4j patching from " + path + " mods file");
                     } else if (normalisedaArg.startsWith("resource=")) {
                         String pathString = arg.trim().substring(9);
                         InputStream in = ClassLoader.getSystemResourceAsStream(pathString);
                         if (in == null) throw new IOException("Unable to load mods resource " + pathString);
                         props = readPropertiesFromStream(in);
-                        System.out.println("Aegis4j patching from " + pathString + " mods resource");
+                        logPrintln("Aegis4j patching from " + pathString + " mods resource");
                     } else {
                         throw new IllegalArgumentException("Aegis4j ERROR: unrecognised parameters " + arg);
                     }

tools/aegis4j/src/main/java/net/gredler/aegis4j/Patcher.java

@@ -50,7 +50,7 @@ public final class Patcher implements ClassFileTransformer {
      * @param block the features to block
      */
     public static void start(Instrumentation instr, Set<String> block, Properties props) throws IOException {
-        System.out.print("Aegis4j patching starting...");
+        AegisAgent.logPrint("Aegis4j patching starting...");
         if (patcher != null) instr.removeTransformer(patcher);
         patcher = new Patcher(block, props);
         instr.addTransformer(patcher, true);
@@ -58,14 +58,14 @@ public final class Patcher implements ClassFileTransformer {
         int count = 0;
         for (String className : patcher.modifications.keySet()) {
             try {
-                if (count > 0) System.out.print(", ");
+                if (count > 0) AegisAgent.logPrint(", ");
-                System.out.print(className);
+                AegisAgent.logPrint(className);
                 Class<?> clazz = Class.forName(className);
                 instr.retransformClasses(clazz);
             } catch (ClassNotFoundException e) {
-                System.out.print("... not present");
+                AegisAgent.logPrint("... not present");
             } catch (NoClassDefFoundError e) {
-                System.out.print("... not present");
+                AegisAgent.logPrint("... not present");
             } catch (UnmodifiableClassException e) {
                 throw new IOException("Problems transforming class", e);
             }
@@ -73,7 +73,7 @@ public final class Patcher implements ClassFileTransformer {
         }
 
         System.setProperty("aegis4j.blocked.features", String.join(",", block));
-        System.out.println(" finished.");
+        AegisAgent.logPrintln(" finished.");
     }
 
     @Override
@@ -103,7 +103,7 @@ public final class Patcher implements ClassFileTransformer {
                     } else {
                         CtMethod[] methods = mod.isAll() ? clazz.getDeclaredMethods() : clazz.getDeclaredMethods(mod.methodName);
                         if (methods.length == 0) {
-                            System.err.println("ERROR: Method not found: " + className + "." + mod.methodName);
+                            System.err.println("Aegis4j ERROR: Method not found: " + className + "." + mod.methodName);
                         }
                         for (CtMethod method : methods) {
                             if (mod.newBody.startsWith("throw ")) {