From 010e4de4e1271e8101530f66f107e59ee1acae15 Mon Sep 17 00:00:00 2001
From: topjohnwu <topjohnwu@gmail.com>
Date: Sun, 4 Aug 2019 23:49:09 -0700
Subject: [PATCH] Introduce DynamicClassLoader

---
 .../magisk/model/download/ManagerUpgrade.kt   |  4 +-
 .../topjohnwu/magisk/ui/home/HomeFragment.kt  |  5 +-
 .../magisk/utils/DynamicClassLoader.kt        | 61 +++++++++++++++++++
 3 files changed, 65 insertions(+), 5 deletions(-)
 create mode 100644 app/src/main/java/com/topjohnwu/magisk/utils/DynamicClassLoader.kt

diff --git a/app/src/main/java/com/topjohnwu/magisk/model/download/ManagerUpgrade.kt b/app/src/main/java/com/topjohnwu/magisk/model/download/ManagerUpgrade.kt
index 26c3e50f9..67cc48b66 100644
--- a/app/src/main/java/com/topjohnwu/magisk/model/download/ManagerUpgrade.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/model/download/ManagerUpgrade.kt
@@ -9,10 +9,10 @@ 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
 import com.topjohnwu.magisk.ui.SplashActivity
+import com.topjohnwu.magisk.utils.DynamicClassLoader
 import com.topjohnwu.magisk.utils.PatchAPK
 import com.topjohnwu.magisk.utils.RootUtils
 import com.topjohnwu.superuser.Shell
-import dalvik.system.DexClassLoader
 import timber.log.Timber
 import java.io.File
 
@@ -27,7 +27,7 @@ private fun RemoteFileService.patchPackage(apk: File, id: Int): File {
         val patched = File(apk.parent, "patched.apk")
         try {
             // Try using the new APK to patch itself
-            val loader = DexClassLoader(apk.path, apk.parent, null, ClassLoader.getSystemClassLoader())
+            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)
diff --git a/app/src/main/java/com/topjohnwu/magisk/ui/home/HomeFragment.kt b/app/src/main/java/com/topjohnwu/magisk/ui/home/HomeFragment.kt
index 3add88815..42f0d47fb 100644
--- a/app/src/main/java/com/topjohnwu/magisk/ui/home/HomeFragment.kt
+++ b/app/src/main/java/com/topjohnwu/magisk/ui/home/HomeFragment.kt
@@ -18,10 +18,10 @@ import com.topjohnwu.magisk.model.events.*
 import com.topjohnwu.magisk.ui.base.MagiskActivity
 import com.topjohnwu.magisk.ui.base.MagiskFragment
 import com.topjohnwu.magisk.utils.ISafetyNetHelper
+import com.topjohnwu.magisk.utils.DynamicClassLoader
 import com.topjohnwu.magisk.view.MarkDownWindow
 import com.topjohnwu.magisk.view.dialogs.*
 import com.topjohnwu.superuser.Shell
-import dalvik.system.DexClassLoader
 import org.koin.androidx.viewmodel.ext.android.viewModel
 import java.io.File
 
@@ -97,8 +97,7 @@ class HomeFragment : MagiskFragment<HomeViewModel, FragmentMagiskBinding>(),
 
     private fun updateSafetyNet(dieOnError: Boolean) {
         try {
-            val loader = DexClassLoader(EXT_APK.path, EXT_APK.parent, null,
-                    ISafetyNetHelper::class.java.classLoader)
+            val loader = DynamicClassLoader(EXT_APK)
             val clazz = loader.loadClass("com.topjohnwu.snet.Snet")
             val helper = clazz.getMethod("newHelper",
                     Class::class.java, String::class.java, Activity::class.java, Any::class.java)
diff --git a/app/src/main/java/com/topjohnwu/magisk/utils/DynamicClassLoader.kt b/app/src/main/java/com/topjohnwu/magisk/utils/DynamicClassLoader.kt
new file mode 100644
index 000000000..9810c91bd
--- /dev/null
+++ b/app/src/main/java/com/topjohnwu/magisk/utils/DynamicClassLoader.kt
@@ -0,0 +1,61 @@
+package com.topjohnwu.magisk.utils
+
+import dalvik.system.DexClassLoader
+import java.io.File
+import java.io.IOException
+import java.net.URL
+import java.util.*
+
+@Suppress("FunctionName")
+inline fun <reified T> T.DynamicClassLoader(apk: File) = DynamicClassLoader(apk, T::class.java.classLoader)
+
+class DynamicClassLoader(apk: File, parent: ClassLoader?)
+    : DexClassLoader(apk.path, apk.parent, null, parent) {
+
+    private val base by lazy { Any::class.java.classLoader!! }
+
+    @Throws(ClassNotFoundException::class)
+    override fun loadClass(name: String, resolve: Boolean) : Class<*>
+        = findLoadedClass(name) ?: runCatching {
+            base.loadClass(name)
+        }.getOrElse {
+            runCatching {
+                findClass(name)
+            }.getOrElse { err ->
+                runCatching {
+                    parent.loadClass(name)
+                }.getOrElse { throw err }
+            }
+        }
+
+    override fun getResource(name: String) = base.getResource(name)
+            ?: findResource(name)
+            ?: parent?.getResource(name)
+
+    @Throws(IOException::class)
+    override fun getResources(name: String): Enumeration<URL> {
+        val resources = mutableListOf(
+                base.getResources(name),
+                findResources(name), parent.getResources(name))
+        return object : Enumeration<URL> {
+            override fun hasMoreElements(): Boolean {
+                while (true) {
+                    if (resources.isEmpty())
+                        return false
+                    if (!resources[0].hasMoreElements()) {
+                        resources.removeAt(0)
+                    } else {
+                        return true
+                    }
+                }
+            }
+
+            override fun nextElement(): URL {
+                if (!hasMoreElements())
+                    throw NoSuchElementException()
+                return resources[0].nextElement()
+            }
+        }
+    }
+
+}