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Hijacking now works (in 1.4.7, at least)
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@unascribed
unascribed committed Jan 30, 2023
1 parent 49ee5be commit 6c3640d
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Showing 9 changed files with 246 additions and 136 deletions.
4 changes: 1 addition & 3 deletions build.gradle
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Original file line number Diff line number Diff line change
Expand Up @@ -38,11 +38,9 @@ dependencies {

shade 'org.cadixdev:lorenz:0.5.6'
shade 'org.cadixdev:lorenz-asm:0.5.6'

shade 'com.grack:nanojson:1.7'

compileOnly 'net.java.dev.jna:jna:5.11.0'

compileOnly 'org.quiltmc:quiltflower:1.8.1'
compileOnly 'org.slf4j:slf4j-api:1.7.9'
compileOnly 'org.apache.logging.log4j:log4j-api:2.17.1'
Expand Down
136 changes: 71 additions & 65 deletions src/main/java/nilloader/NilAgent.java
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Original file line number Diff line number Diff line change
Expand Up @@ -10,10 +10,12 @@
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.Instrumentation;
import java.lang.management.ManagementFactory;
import java.net.MalformedURLException;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.security.ProtectionDomain;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
Expand Down Expand Up @@ -54,6 +56,8 @@
import nilloader.api.NilMetadata;
import nilloader.api.lib.mini.MiniTransformer;
import nilloader.api.lib.qdcss.QDCSS;
import nilloader.impl.fixes.EarlyMiniTransformer;
import nilloader.impl.fixes.ModuleClassLoaderTransformer;
import nilloader.impl.fixes.NewKnotClassLoaderTransformer;
import nilloader.impl.fixes.OldKnotClassLoaderTransformer;
import nilloader.impl.fixes.RelaunchClassLoaderTransformer;
Expand Down Expand Up @@ -107,7 +111,6 @@ public EntrypointListener(String id, String className) {
private static Instrumentation instrumentation;

private static String activeMod = null;
private static int initializations = 0;
private static int nilAgents = 1;

private static boolean frozen = false;
Expand All @@ -119,13 +122,13 @@ public static void agentmain(String arg, Instrumentation ins) {
}

public static void premain(String arg, Instrumentation ins) {
initializations++;
if (initializations > 1) {
NilLoaderLog.log.debug("Initializing for the {} time...", nth(initializations));
NilAgentPart.initializations++;
if (NilAgentPart.initializations > 1) {
NilLoaderLog.log.debug("Initializing for the {} time...", nth(NilAgentPart.initializations));
// Multiple nilmods are being added as Java agents; don't do a full reinit
// We need to delay performing final initialization until the last agent initializes to
// ensure all the agent jars are on the classpath
if (initializations == nilAgents) {
if (NilAgentPart.initializations == nilAgents) {
completePremain(ins);
}
return;
Expand All @@ -140,18 +143,42 @@ public static void premain(String arg, Instrumentation ins) {
}, ins.isRetransformClassesSupported());
}
loadTracker = (loader, className, classBeingRedefined, protectionDomain, classfileBuffer) -> {
if (loadedClasses != null) memoize(className, loader);
if (loadedClasses != null && classBeingRedefined == null) memoize(className, loader);
return classfileBuffer;
};
ins.addTransformer(loadTracker);
for (Class<?> c : ins.getAllLoadedClasses()) {
if (DEBUG_CLASSLOADING) {
ProtectionDomain protectionDomain = c.getProtectionDomain();
System.err.printf("Already loaded class %s via %s from %s%n", c.getName().replace('.', '/'), c.getClassLoader(),
(protectionDomain != null && protectionDomain.getCodeSource() != null) ? protectionDomain.getCodeSource().getLocation() : "[unknown]");
}
memoize(c.getName(), c.getClassLoader());
}

// TODO it'd be nice to do this in a more generic way instead of needing loader-specific hacks
builtInTransformers.add(new RelaunchClassLoaderTransformer());
builtInTransformers.add(new NewKnotClassLoaderTransformer());
builtInTransformers.add(new OldKnotClassLoaderTransformer());
if (loadedClasses.containsKey("cpw.mods.fml.relauncher.RelaunchClassLoader")) {
try {
Class<?> relauncherClazz = Class.forName("cpw.mods.fml.relauncher.FMLRelauncher");
Class<?> loaderClazz = Class.forName("cpw.mods.fml.relauncher.RelaunchClassLoader");
Method instance = relauncherClazz.getDeclaredMethod("instance");
instance.setAccessible(true);
Object relauncher = instance.invoke(null);
Field classLoader = relauncherClazz.getDeclaredField("classLoader");
classLoader.setAccessible(true);
Object loader = classLoader.get(relauncher);
Method addExclusion = loaderClazz.getDeclaredMethod("addClassLoaderExclusion", String.class);
addExclusion.setAccessible(true);
addExclusion.invoke(loader, "nilloader.");
} catch (Throwable t) {
NilLoaderLog.log.error("Failed to fix FML relauncher", t);
}
} else {
registerTransformer(new RelaunchClassLoaderTransformer());
}
registerTransformer(new NewKnotClassLoaderTransformer());
registerTransformer(new OldKnotClassLoaderTransformer());
registerTransformer(new ModuleClassLoaderTransformer());

ins.addTransformer((loader, className, classBeingRedefined, protectionDomain, classfileBuffer) -> {
if (className == null) return classfileBuffer;
Expand All @@ -172,17 +199,16 @@ public static void premain(String arg, Instrumentation ins) {
NilLoaderLog.log.error("Failed to load debug mappings", e);
}
}
URL us = getJarURL(NilAgent.class.getProtectionDomain().getCodeSource().getLocation());
URL us = NilAgentPart.getJarURL(NilAgent.class.getProtectionDomain().getCodeSource().getLocation());
try {
discover("nilloader", NilAgent.class.getClassLoader(), new File(us.toURI()));
} catch (URISyntaxException e) {
throw new AssertionError(e);
}
NilLoaderLog.log.info("NilLoader v{} initialized, logging via {}", mods.get("nilloader").version, NilLoaderLog.log.getImplementationName());
NilLoaderLog.log.info("NilLoader v{} initialized{}, logging via {}", mods.get("nilloader").version, hijacked ? " via hijack" : "", NilLoaderLog.log.getImplementationName());
File ourFile = null;
try {
ourFile = new File(us.toURI());
additionalClassPath.add(ourFile);
discover(ourFile, false);
} catch (URISyntaxException | IllegalArgumentException e) {
NilLoaderLog.log.debug("Failed to discover additional nilmods in our jar", e);
Expand Down Expand Up @@ -270,6 +296,7 @@ private static void completePremain(Instrumentation ins) {
File f = en.getKey();
try {
classSourceURLs.put(f.toURI().toURL(), en.getValue());
classSourceURLs.put(f.getCanonicalFile().toURI().toURL(), en.getValue());
} catch (IOException e) {
NilLoaderLog.log.error("Failed to add {} to class map", f, e);
}
Expand All @@ -289,26 +316,32 @@ private static void completePremain(Instrumentation ins) {
javaClassPathAddn.append(File.pathSeparator).append(f.getPath());
}
System.setProperty("java.class.path", System.getProperty("java.class.path")+javaClassPathAddn);

ins.addTransformer((loader, className, classBeingRedefined, protectionDomain, classfileBuffer) -> {
if (classBeingRedefined != null || className == null) return classfileBuffer;
if (protectionDomain != null && protectionDomain.getCodeSource() != null) {
String definer = getDefiningMod(protectionDomain.getCodeSource().getLocation());
if (definer != null && isFrozen()) {
MappingSet mappings = getActiveMappings(definer);
if (mappings != null) {
NilLoaderLog.log.debug("Remapping mod class {} via mapping set {}", className, NilAgent.getActiveMappingId(definer));
classfileBuffer = remap(loader, classfileBuffer, mappings);
if (DEBUG_DUMP_MODREMAPPED) {
writeDump(className, classfileBuffer, "modRemapped", "class");
}
if (DEBUG_DECOMPILE_MODREMAPPED) {
byte[] finalBys = classfileBuffer.clone();
decompilerThread.execute(() -> {
writeDump(className, Decompiler.decompile(className, finalBys).getBytes(StandardCharsets.UTF_8), "modRemapped", "java");
});
if (className.startsWith("nilloader/")) return classfileBuffer; // break class loading loop when hijacking
try {
if (classBeingRedefined != null || className == null) return classfileBuffer;
if (protectionDomain != null && protectionDomain.getCodeSource() != null) {
String definer = getDefiningMod(protectionDomain.getCodeSource().getLocation(), 0);
if (definer != null && isFrozen()) {
MappingSet mappings = getActiveMappings(definer);
if (mappings != null) {
NilLoaderLog.log.debug("Remapping mod class {} via mapping set {}", className, NilAgent.getActiveMappingId(definer));
classfileBuffer = remap(loader, classfileBuffer, mappings);
if (DEBUG_DUMP_MODREMAPPED) {
writeDump(className, classfileBuffer, "modRemapped", "class");
}
if (DEBUG_DECOMPILE_MODREMAPPED) {
byte[] finalBys = classfileBuffer.clone();
decompilerThread.execute(() -> {
writeDump(className, Decompiler.decompile(className, finalBys).getBytes(StandardCharsets.UTF_8), "modRemapped", "java");
});
}
}
}
}
} catch (Throwable t) {
NilLoaderLog.log.error("Exception while remapping class {}", className, t);
}
return classfileBuffer;
});
Expand Down Expand Up @@ -554,7 +587,7 @@ private static void discover(String id, ClassLoader classLoader, File src) {
}

public static void fireEntrypoint(String entrypoint) {
if (initializations == 0) {
if (NilAgentPart.initializations == 0) {
NilLoaderLog.log.error("fireEntrypoint called on an uninitialized NilLoader; classloading shenanigans? I was loaded by {}", NilAgent.class.getClassLoader());
return;
}
Expand Down Expand Up @@ -753,47 +786,24 @@ public static MappingSet getActiveMappings(String mod) {
return modMappings.getOrDefault(mod, Collections.emptyMap()).getOrDefault(getActiveMappingId(mod), null);
}

public static URL getJarURL(URL codeSource) {
if ("jar".equals(codeSource.getProtocol())) {
String str = codeSource.toString().substring(4);
int bang = str.indexOf('!');
if (bang != -1) str = str.substring(0, bang);
try {
return new URL(str);
} catch (MalformedURLException e) {
return null;
}
} else if ("union".equals(codeSource.getProtocol())) {
// some ModLauncher nonsense
String str = codeSource.toString().substring(6);
int bullshit = str.indexOf("%23");
if (bullshit != -1) str = str.substring(0, bullshit);
try {
return new URL("file:"+str);
} catch (MalformedURLException e) {
return null;
}
}
return codeSource;
}

public static String getDefiningMod(URL codeSource) {
public static String getDefiningMod(URL codeSource, int depth) {
String raw = classSourceURLs.get(codeSource);
if (raw == null) {
return getDefiningMod(getJarURL(codeSource));
if (raw == null && depth < 5) {
return getDefiningMod(NilAgentPart.getJarURL(codeSource), depth+1);
}
return raw;
}

public static void registerTransformer(ClassTransformer transformer) {
if (frozen) throw new IllegalStateException("Transformers must be registered during the premain entrypoint (or earlier)");
if (frozen) throw new IllegalStateException("Transformers must be registered during or before the premain/hijack entrypoints");
List<ClassTransformer> transformers = transformer instanceof EarlyMiniTransformer ? NilAgent.builtInTransformers : NilAgent.transformers;
if (transformer instanceof ClassRetransformer) {
ClassRetransformer cr = (ClassRetransformer)transformer;
transformers.add(transformer);
for (String s : cr.getTargets()) {
if (loadedClasses.containsKey(s)) {
if (loadedClasses.containsKey(s.replace('/', '.'))) {
try {
for (ClassLoader cl : loadedClasses.get(s)) {
for (ClassLoader cl : loadedClasses.get(s.replace('/', '.'))) {
try {
instrumentation.retransformClasses(Class.forName(s, false, cl));
} catch (ClassNotFoundException e) {}
Expand All @@ -807,7 +817,7 @@ public static void registerTransformer(ClassTransformer transformer) {
} else {
if (transformer instanceof MiniTransformer) {
MiniTransformer mini = (MiniTransformer)transformer;
if (loadedClasses.containsKey(mini.getClassTargetName())) {
if (loadedClasses.containsKey(mini.getClassTargetName().replace('/', '.'))) {
throw new IllegalStateException("Cannot register transformer for already loaded class: "+mini.getClassTargetName());
}
}
Expand Down Expand Up @@ -837,8 +847,4 @@ static void injectToSearchPath(JarFile file) {
instrumentation.appendToSystemClassLoaderSearch(file);
}

public static int getInitializations() {
return initializations;
}

}
42 changes: 42 additions & 0 deletions src/main/java/nilloader/NilAgentPart.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,42 @@
package nilloader;

import java.net.MalformedURLException;
import java.net.URL;

/**
* Some state stuff split out of NilAgent to avoid duplicate class loading with hijacks
*/
public class NilAgentPart {

static int initializations = 0;

public static URL getJarURL(URL codeSource) {
if (codeSource == null) return null;
if ("jar".equals(codeSource.getProtocol())) {
String str = codeSource.toString().substring(4);
int bang = str.indexOf('!');
if (bang != -1) str = str.substring(0, bang);
try {
return new URL(str);
} catch (MalformedURLException e) {
return null;
}
} else if ("union".equals(codeSource.getProtocol())) {
// some ModLauncher nonsense
String str = codeSource.toString().substring(6);
int bullshit = str.indexOf("%23");
if (bullshit != -1) str = str.substring(0, bullshit);
try {
return new URL("file:"+str);
} catch (MalformedURLException e) {
return null;
}
}
return codeSource;
}

public static int getInitializations() {
return initializations;
}

}
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