Do not use string resources for app label

This not only simplifies hiding stub APKs (no resource IDs involved),
but also opens the opportunity to allow users to customize whatever
app name they want after it is hidden.

app/proguard-rules.pro

@@ -32,7 +32,7 @@
 -keep,allowobfuscation class * extends com.topjohnwu.magisk.base.DelegateWorker
 
 # BootSigner
--keepclassmembers class com.topjohnwu.signing.BootSigner { *; }
+-keep class a.a { *; }
 
 # Strip logging
 -assumenosideeffects class timber.log.Timber.Tree { *; }

app/src/main/java/a/a.java

@@ -1,18 +1,21 @@
 package a;
 
-import androidx.annotation.Keep;
 import androidx.core.app.AppComponentFactory;
 
 import com.topjohnwu.magisk.utils.PatchAPK;
 import com.topjohnwu.signing.BootSigner;
 
-@Keep
 public class a extends AppComponentFactory {
 
+    @Deprecated
     public static boolean patchAPK(String in, String out, String pkg) {
         return PatchAPK.patch(in, out, pkg);
     }
 
+    public static boolean patchAPK(String in, String out, String pkg, String label) {
+        return PatchAPK.patch(in, out, pkg, label);
+    }
+
     public static void main(String[] args) throws Exception {
         BootSigner.main(args);
     }

app/src/main/java/com/topjohnwu/magisk/model/download/ManagerUpgrade.kt

@@ -4,7 +4,6 @@ import com.topjohnwu.magisk.BuildConfig
 import com.topjohnwu.magisk.Config
 import com.topjohnwu.magisk.R
 import com.topjohnwu.magisk.cmp
-import com.topjohnwu.magisk.extensions.DynamicClassLoader
 import com.topjohnwu.magisk.model.entity.internal.Configuration.APK.Restore
 import com.topjohnwu.magisk.model.entity.internal.Configuration.APK.Upgrade
 import com.topjohnwu.magisk.model.entity.internal.DownloadSubject
@@ -12,7 +11,6 @@ import com.topjohnwu.magisk.ui.SplashActivity
 import com.topjohnwu.magisk.utils.PatchAPK
 import com.topjohnwu.magisk.utils.Utils
 import com.topjohnwu.superuser.Shell
-import timber.log.Timber
 import java.io.File
 
 private fun RemoteFileService.patchPackage(apk: File, id: Int) {
@@ -24,17 +22,7 @@ private fun RemoteFileService.patchPackage(apk: File, id: Int) {
                     .setContentText("")
         }
         val patched = File(apk.parent, "patched.apk")
-        try {
+        PatchAPK.patch(apk, patched, packageName, applicationInfo.nonLocalizedLabel.toString())
-            // Try using the new APK to patch itself
-            val loader = DynamicClassLoader(apk)
-            loader.loadClass("a.a")
-                    .getMethod("patchAPK", String::class.java, String::class.java, String::class.java)
-                    .invoke(null, apk.path, patched.path, packageName)
-        } catch (e: Exception) {
-            Timber.e(e)
-            // Fallback to use the current implementation
-            PatchAPK.patch(apk.path, patched.path, packageName)
-        }
         apk.delete()
         patched.renameTo(apk)
     }

app/src/main/java/com/topjohnwu/magisk/ui/settings/SettingsFragment.kt

@@ -67,7 +67,8 @@ class SettingsFragment : BasePreferenceFragment() {
         val suCategory = findPreference<PreferenceCategory>("superuser")!!
         val hideManager = findPreference<Preference>("hide")!!
         hideManager.setOnPreferenceClickListener {
-            PatchAPK.hideManager(requireContext())
+            // TODO: Add UI to allow user to customize app name
+            PatchAPK.hideManager(requireContext(), "Manager")
             true
         }
         val restoreManager = findPreference<Preference>("restore")

app/src/main/java/com/topjohnwu/magisk/utils/PatchAPK.kt

@@ -3,6 +3,7 @@ package com.topjohnwu.magisk.utils
 import android.content.Context
 import android.widget.Toast
 import com.topjohnwu.magisk.*
+import com.topjohnwu.magisk.extensions.DynamicClassLoader
 import com.topjohnwu.magisk.extensions.subscribeK
 import com.topjohnwu.magisk.ui.SplashActivity
 import com.topjohnwu.magisk.view.Notifications
@@ -46,52 +47,38 @@ object PatchAPK {
     }
 
     private fun findAndPatch(xml: ByteArray, from: String, to: String): Boolean {
-        if (from.length != to.length)
+        if (to.length > from.length)
             return false
         val buf = ByteBuffer.wrap(xml).order(ByteOrder.LITTLE_ENDIAN).asCharBuffer()
         val offList = mutableListOf<Int>()
         var i = 0
-        while (i < buf.length - from.length) {
+        loop@ while (i < buf.length - from.length) {
-            var match = true
+            for (j in from.indices) {
-            for (j in 0 until from.length) {
                 if (buf.get(i + j) != from[j]) {
-                    match = false
+                    ++i
-                    break
+                    continue@loop
                 }
             }
-            if (match) {
             offList.add(i)
             i += from.length
         }
-            ++i
-        }
         if (offList.isEmpty())
             return false
+
+        val toBuf = to.toCharArray().copyOf(from.length)
         for (off in offList) {
             buf.position(off)
-            buf.put(to)
+            buf.put(toBuf)
         }
         return true
     }
 
-    private fun findAndPatch(xml: ByteArray, a: Int, b: Int): Boolean {
+    private fun patchAndHide(context: Context, label: String): Boolean {
-        val buf = ByteBuffer.wrap(xml).order(ByteOrder.LITTLE_ENDIAN).asIntBuffer()
-        val len = xml.size / 4
-        for (i in 0 until len) {
-            if (buf.get(i) == a) {
-                buf.put(i, b)
-                return true
-            }
-        }
-        return false
-    }
-
-    private fun patchAndHide(context: Context): Boolean {
         // Generate a new app with random package name
         val repack = File(context.filesDir, "patched.apk")
         val pkg = genPackageName("com.", BuildConfig.APPLICATION_ID.length)
 
-        if (!patch(context.packageCodePath, repack.path, pkg))
+        if (!patch(context.packageCodePath, repack.path, pkg, label))
             return false
 
         // Install the application
@@ -107,14 +94,15 @@ object PatchAPK {
     }
 
     @JvmStatic
-    fun patch(apk: String, out: String, pkg: String): Boolean {
+    @JvmOverloads
+    fun patch(apk: String, out: String, pkg: String, label: String = "Manager"): Boolean {
         try {
             val jar = JarMap(apk)
             val je = jar.getJarEntry(Const.ANDROID_MANIFEST)
             val xml = jar.getRawData(je)
 
             if (!findAndPatch(xml, BuildConfig.APPLICATION_ID, pkg) ||
-                    !findAndPatch(xml, R.string.app_name, R.string.re_app_name))
+                    !findAndPatch(xml, "Magisk Manager", label))
                 return false
 
             // Write apk changes
@@ -128,11 +116,32 @@ object PatchAPK {
         return true
     }
 
-    fun hideManager(context: Context) {
+    fun patch(apk: File, out: File, pkg: String, label: String): Boolean {
+        try {
+            // Try using the new APK to patch itself
+            val loader = DynamicClassLoader(apk)
+            val cls = loader.loadClass("a.a")
+
+            for (m in cls.declaredMethods) {
+                val pars = m.parameterTypes
+                if (pars.size == 4 && pars[0] == String::class.java) {
+                    return m.invoke(null, apk.path, out.path, pkg, label) as Boolean
+                }
+            }
+            throw Exception("No matching method found")
+        } catch (e: Exception) {
+            Timber.e(e)
+            // Fallback to use the current implementation
+            patch(apk.path, out.path, pkg, label)
+        }
+        return false
+    }
+
+    fun hideManager(context: Context, label: String) {
         Completable.fromAction {
             val progress = Notifications.progress(context, context.getString(R.string.hide_manager_title))
             Notifications.mgr.notify(Const.ID.HIDE_MANAGER_NOTIFICATION_ID, progress.build())
-            if (!patchAndHide(context))
+            if (!patchAndHide(context, label))
                 Utils.toast(R.string.hide_manager_fail_toast, Toast.LENGTH_LONG)
             Notifications.mgr.cancel(Const.ID.HIDE_MANAGER_NOTIFICATION_ID)
         }.subscribeK()

shared/src/main/AndroidManifest.xml

@@ -8,7 +8,7 @@
     <application
         android:icon="@drawable/ic_launcher"
         android:installLocation="internalOnly"
-        android:label="@string/app_name"
+        android:label="Magisk Manager"
         android:supportsRtl="true">
 
         <activity