Clean hook

README.md

@@ -14,33 +14,22 @@ LSPatch provides a way to insert dex and so into the target APK by repackaging.
 1. download the artifact
 1. run `java -jar lspatch.jar`
 
+## Dev
+
+```
+Android Studio Arctic Fox | 2020.3.1 +
+```
+
 ## Build
 
 ```
-Android Studio Arctic Fox | 2020.3.1 Beta 3
+gradlew build<Debug|Release>
-```
-
-```
-gradlew build[Debug|Release]
 ```
 
 ## Supported Android Versions
-Same with [LSPosed](
-https://github.com/LSPosed/LSPosed#supported-versions)
 
-## Principle
+In theory, same with [LSPosed](https://github.com/LSPosed/LSPosed#supported-versions)
-
-1. Decompress target APK.
-1. Patch the app property of AndroidManifest.xml in the target APK, changing it to the Application class in the inserted dex.
-1. Copy all files in `list-so`, `list-assets`, `list-dex` into target APK.
-1. Package and sign target APK.
-
-Running Stage:
-1. Inserted dex initializes LSPosed
-1. New ClassLoader from `assets/lsploader.dex`.
-1. Loads the Xposed module installed in the system with new ClassLoader.
 
 ## Known issues
 
 1. Can't solve the signature verification issue perfectly
-1. If you use under Windows, you need open `CMD/Powershell` with `Run as Administrator`, See [Code](https://github.com/LSPosed/LSPatch/blob/ab1a213161f90ec7ac604df47434201170b92b9a/patch/src/main/java/org/lsposed/patch/util/FileUtils.java#L67-L70).

app/src/main/java/org/lsposed/lspatch/loader/LSPApplication.java

@@ -68,8 +68,6 @@ public class LSPApplication extends ApplicationServiceClient {
     private static ClassLoader appClassLoader;
     private static Object activityThread;
 
-    private static int TRANSACTION_getPackageInfo_ID = -1;
-
     final static public int FIRST_APP_ZYGOTE_ISOLATED_UID = 90000;
     final static public int PER_USER_RANGE = 100000;
 
@@ -277,27 +275,14 @@ public class LSPApplication extends ApplicationServiceClient {
         }
     }
 
-    private static void byPassSignature(Context context) throws ClassNotFoundException, IllegalAccessException {
+    private static int getTranscationId(String clsName, String trasncationName) throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException {
-        Field[] pmStubFields = Class.forName("android.content.pm.IPackageManager$Stub").getDeclaredFields();
+        Field field = Class.forName(clsName).getDeclaredField(trasncationName);
-        for (Field field : pmStubFields) {
-            if (!Modifier.isStatic(field.getModifiers()) || field.getType() != int.class) {
-                continue;
-            }
         field.setAccessible(true);
-            int fieldValue = field.getInt(null);
+        return field.getInt(null);
-            String fieldName = field.getName();
-            field.setAccessible(false);
-
-            if (fieldName.equals("TRANSACTION_getPackageInfo")) {
-                TRANSACTION_getPackageInfo_ID = fieldValue;
-                break;
-            }
-        }
-
-        if (TRANSACTION_getPackageInfo_ID == -1) {
-            throw new IllegalStateException("getPackageInfo transaction id null");
     }
 
+    private static void byPassSignature(Context context) throws ClassNotFoundException, IllegalAccessException, NoSuchFieldException {
+        final int TRANSACTION_getPackageInfo = getTranscationId("android.content.pm.IPackageManager$Stub", "TRANSACTION_getPackageInfo");
         XposedHelpers.findAndHookMethod("android.os.BinderProxy", appClassLoader, "transact", int.class, Parcel.class, Parcel.class, int.class, new XC_MethodHook() {
             @Override
             protected void afterHookedMethod(MethodHookParam param) throws Throwable {
@@ -322,7 +307,7 @@ public class LSPApplication extends ApplicationServiceClient {
                     if (desc == null || desc.isEmpty() || !desc.equals("android.content.pm.IPackageManager")) {
                         return;
                     }
-                    if (id == TRANSACTION_getPackageInfo_ID) {
+                    if (id == TRANSACTION_getPackageInfo) {
                         out.readException();
                         if (0 != out.readInt()) {
                             PackageInfo packageInfo = PackageInfo.CREATOR.createFromParcel(out);
@@ -352,13 +337,14 @@ public class LSPApplication extends ApplicationServiceClient {
                         out.setDataPosition(0);
                     }
                 } catch (Throwable err) {
-                    err.printStackTrace();
+                    // should not happen, just crash app
+                    throw new IllegalStateException("lsp hook error", err);
                 }
             }
         });
     }
 
-    private static void doHook(Context context) throws IllegalAccessException, ClassNotFoundException, IOException {
+    private static void doHook(Context context) throws IllegalAccessException, ClassNotFoundException, IOException, NoSuchFieldException {
         if (isApplicationProxied()) {
             hookContextImplSetOuterContext();
             hookInstallContentProviders();

patch/src/main/java/org/lsposed/patch/LSPatch.java

@@ -38,6 +38,10 @@ import java.util.jar.JarFile;
 public class LSPatch {
 
     static class PatchError extends Error {
+        public PatchError(String message, Throwable cause) {
+            super(message, cause);
+        }
+
         PatchError(String message) {
             super(message);
         }
@@ -254,7 +258,8 @@ public class LSPatch {
                 try (var is = getClass().getClassLoader().getResourceAsStream("assets/so/" + (arch.equals("armeabi") ? "armeabi-v7a" : arch) + "/liblspd.so")) {
                     zFile.add(entryName, is, false); // no compress for so
                 } catch (Throwable e) {
-                    throw new PatchError("Error when adding native lib: " + e);
+                    // More exception info
+                    throw new PatchError("Error when adding native lib", e);
                 }
                 if (verbose)
                     System.out.println("added " + entryName);