{"id":385,"date":"2022-04-24T20:07:13","date_gmt":"2022-04-24T12:07:13","guid":{"rendered":"http:\/\/pareto.fun\/?p=385"},"modified":"2022-04-24T20:07:14","modified_gmt":"2022-04-24T12:07:14","slug":"androidlowlevel-%e6%9c%aa%e5%ae%8c%e5%be%85%e7%bb%ad","status":"publish","type":"post","link":"http:\/\/pareto.fun\/?p=385","title":{"rendered":"androidLowLevel – \u672a\u5b8c\u5f85\u7eed"},"content":{"rendered":"\n

ART – \u53cc\u4eb2\u59d4\u6d3e\u673a\u5236<\/h1>\n\n\n\n

motivation<\/h2>\n\n\n\n

\u4e86\u89e3\u70ed\u4fee\u590d\u5b9e\u73b0\u673a\u5236\uff0c\u80fd\u591fhook \u70ed\u4fee\u590d\u4e2d\u7684\u4ee3\u7801\u3002<\/p>\n\n\n\n

\u70ed\u4fee\u590d\uff1a<\/p>\n\n\n\n

\u4e0d\u901a\u8fc7\u91cd\u65b0\u4e0b\u8f7d\u5b89\u88c5\u5305\uff0c\u5b89\u88c5apk \uff0c\u6765\u66f4\u65b0APK\u7684\u76ee\u7684\u3002<\/p>\n\n\n\n

ClassLoader<\/h2>\n\n\n\n

\u7528\u4e8e\u88c5\u8f7dClass\u7684\u88c5\u8f7d\u5668\uff0c\u8fd9\u4e2a\u7c7b\u52a0\u8f7d\u5668\u80fd\u8fbe\u5230\u4ec0\u4e48\u6548\u679c\uff1f<\/p>\n\n\n\n

  1. \u7528\u6237\u65e0\u9700\u5173\u5fc3\u7c7b\u52a0\u8f7d\u7684\u6d41\u7a0b\u3002<\/li>
  2. \u5b9e\u73b0\u7528\u65f6\u52a0\u8f7d\u3002<\/li><\/ol>\n\n\n\n

    \u4e00\u4e9b\u57fa\u7840\u7684ClassLoader\uff1a<\/strong><\/p>\n\n\n\n

    BootClassLoader \u52a0\u8f7d\u7cfb\u7edf\u57fa\u7840\u5e93\uff0c\u6bd4\u5982 java.lang.String \u3002<\/p>\n\n\n\n

    PathClassLoader \u7528\u4e8e\u52a0\u8f7dApk\u4e2d\u7684dex\u6587\u4ef6\uff0c\u6574\u4e2aapk\u7684class\u90fd\u53ef\u4ee5\u627e\u5230\u3002<\/p>\n\n\n\n

    DexClassLoader \u5e38\u7528\u4e8e\u63d2\u4ef6\u5316\u8bbe\u8ba1\uff0c\u63d2\u4ef6\u7684ClassLoader\u96c6\u6210\u8be5\u7c7b\u3002<\/p>\n\n\n\n

    \u52a0\u8f7d\u903b\u8f91<\/strong><\/p>\n\n\n\n

    1. \u5982\u679c\u4e00\u4e2a\u7c7b\u52a0\u8f7d\u5668\u52a0\u8f7d\u4e86\u4e00\u4e2a\u7c7b\uff0c\u90a3\u4e48\u8fd9\u4e2a\u7c7b\u52a0\u8f7d\u5668\u5c06\u8fd9\u4e2a\u7c7b\u7f13\u5b58\u8d77\u6765\u3002\u6bcf\u6b21\u52a0\u8f7d\u7c7b\u7684\u65f6\u5019\uff0c\u9996\u5148\u4f1a\u5148\u8bbf\u95ee\u6307\u5b9a\u7c7b\u52a0\u8f7d\u5668\u7684\u7f13\u5b58\uff0c\u82e5\u7f13\u5b58\u4e2d\u5b58\u5728\uff0c\u5c31\u76f4\u63a5\u4ece\u7f13\u51b2\u533a\u91cc\u8fd4\u56de\u5373\u53ef\uff0c\u8fd9\u53ef\u4ee5\u63d0\u9ad8\u7c7b\u52a0\u8f7d\u7684\u6027\u80fd\u3002(\u672a\u4ece\u4ee3\u7801\u53d1\u73b0\u8be5\u903b\u8f91)<\/li>
    2. \u5982\u679c\u7f13\u51b2\u533a\u627e\u4e0d\u5230\uff0c\u8bf4\u660e\u662f\u7b2c\u4e00\u6b21\u52a0\u8f7d\uff0c\u90a3\u4e48\u5982\u679c\u6307\u5b9a\u7c7b\u52a0\u8f7d\u5668\u6709\u7236\u52a0\u8f7d\u5668\uff0c\u5219\u4f18\u5148\u8ba9\u7236\u52a0\u8f7d\u5668\u52a0\u8f7d\u8be5\u7c7b\u3002\u6240\u4ee5\u7c7b\u52a0\u8f7d\u5668\u5177\u6709\u5c42\u7ea7\u5173\u7cfb\u3002\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff0c\u8d1f\u8d23\u52a0\u8f7d Java \u57fa\u672c\u7c7b\u548c\u6269\u5c55\u7c7b\u7684\u7c7b\u52a0\u8f7d\u5668\u5fc5\u987b\u5904\u4e8e\u7c7b\u52a0\u8f7d\u5668\u5c42\u7ea7\u4e2d\u7684\u9876\u5c42\u3002\u7236\u52a0\u8f7d\u5668\u52a0\u8f7d\u7c7b\u7684\u8fc7\u7a0b\u4e5f\u9075\u5faa\u540c\u6837\u7684\u89c4\u5219\u3002<\/li>
    3. \u5982\u679c\u6ca1\u6709\u7236\u52a0\u8f7d\u5668\u6216\u8005\u7236\u52a0\u8f7d\u5668\u4e5f\u52a0\u8f7d\u4e0d\u5230\uff0c\u5219\u8fd4\u56de\u5f53\u524d\u7c7b\u52a0\u8f7d\u5668\uff0c\u7531\u81ea\u5df1\u8bfb\u5165\u5b57\u8282\u7801\u5e76\u59d4\u6258\u865a\u62df\u673a\u6267\u884c\u540e\u7eed\u52a0\u8f7d\u8fc7\u7a0b\u4e14\u8fd4\u56de\u751f\u6210\u7684\u7c7b\u3002<\/li><\/ol>\n\n\n\n

      \u76f8\u5173\u4ee3\u7801\u5b9e\u73b0<\/p>\n\n\n\n

      public abstract class ClassLoader {
          
          ...
          ...
          ...
          
          protected Class<?> loadClass(String name, boolean resolve)
              throws ClassNotFoundException
          {
                  \/\/ First, check if the class has already been loaded
                  Class<?> c = findLoadedClass(name);
                  if (c == null) {
                      try {
                          if (parent != null) {
                              c = parent.loadClass(name, false);
                          } else {
                              c = findBootstrapClassOrNull(name);
                          }
                      } catch (ClassNotFoundException e) {
                          \/\/ ClassNotFoundException thrown if class not found
                          \/\/ from the non-null parent class loader
                      }
      \u200b
                      if (c == null) {
                          \/\/ If still not found, then invoke findClass in order
                          \/\/ to find the class.
                          c = findClass(name);
                      }
                  }
                  return c;
          }
          ...
          ...
          ...
      }
      \u200b<\/pre>\n\n\n\n
      \u63d2\u4ef6\u5316\u5b9e\u4f8b<\/h2>\n\n\n\n
      \u53c2\u8003\u9879\u76ee:https:\/\/github.com\/Catherine22\/ClassLoader<\/a><\/p><\/blockquote>\n\n\n\n
      MyDexClassLoader\u7684\u58f0\u660e,\u5173\u6ce8\u7c7b\u7684\u7ee7\u627f\u5173\u7cfb. MyDexClassLoader <- DexClassLoader <- BaseDexClassLoader <- ClassLoader<\/p>\n\n\n\n
      package com.catherine.classloader;
      \u200b
      import android.content.Context;
      import android.util.Log;
      \u200b
      import java.net.URL;
      import java.util.Enumeration;
      \u200b
      import dalvik.system.DexClassLoader;
      \u200b
      \/**
       * Created by Catherine on 2017\/2\/13.
       * yacatherine19@gmail.com
       *\/
      \u200b
      \/**
       * DexClassLoader:
       * A class loader that loads classes from .jar and .apk files containing a classes.dex entry.
       * This can be used to execute code not installed as part of an application.
       *\/
      public class MyDexClassLoader extends DexClassLoader {
          private static final String TAG = \"MyDexClassLoader\";
      \u200b
          \/**
           * @param application MyApplication
           * @param dexPath     String: the list of jar\/apk files containing classes and resources, delimited by File.pathSeparator, which defaults to \":\" on Android
           * @param soPath      native libraries (path of .so files)
           * @param classloader the parent class loader
           *\/
          public MyDexClassLoader(MyApplication application, String dexPath, String soPath, ClassLoader classloader) {
              super(dexPath, application.getDir(\"dex\", Context.MODE_PRIVATE).getAbsolutePath(), soPath.replace(\"files\", \"lib\"),
                      classloader);
      \u200b
              Log.i(TAG, \"DexClassLoader \" + classloader.toString());
              Log.i(TAG, \"dexPath \" + dexPath);
              Log.i(TAG, \"optimizedDirectory \" + application.getDir(\"dex\", Context.MODE_PRIVATE).getAbsolutePath());
              Log.i(TAG, \"soPath_lib \" + soPath);
              Log.i(TAG, \"librarySearchPath \" + soPath.replace(\"files\", \"lib\"));
      \u200b
          }
      \u200b
          @Override
          protected Class<?> findClass(String name) throws ClassNotFoundException {
              Log.i(TAG, \"findClass:\" + name);
              return super.findClass(name);
          }
      \u200b
          @Override
          public String findLibrary(String name) {
              Log.i(TAG, \"findLibrary:\" + name);
              return super.findLibrary(name);
          }
      \u200b
          @Override
          protected URL findResource(String name) {
              Log.i(TAG, \"findResource:\" + name);
              return super.findResource(name);
          }
      \u200b
          @Override
          protected Enumeration<URL> findResources(String name) {
              Log.i(TAG, \"findResources:\" + name);
              return super.findResources(name);
          }
      \u200b
          @Override
          protected synchronized Package getPackage(String name) {
              Log.i(TAG, \"getPackage:\" + name);
              return super.getPackage(name);
          }
      \u200b
          @Override
          public Class<?> loadClass(String name) throws ClassNotFoundException{
              Log.d(TAG, \"loadClass:\" + name);
              return super.loadClass(name);
          }
      \u200b
          @Override
          protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException{
              Log.d(TAG, \"loadClass:\" + name + \" : \" + resolve);
              return super.loadClass(name, resolve);
          }
      }<\/pre>\n\n\n\n
      \u770b\u770bDexClassLoader<\/p>\n\n\n\n
      public class DexClassLoader extends BaseDexClassLoader {
          \/**
           * Creates a {@code DexClassLoader} that finds interpreted and native
           * code.  Interpreted classes are found in a set of DEX files contained
           * in Jar or APK files.
           *
           * <p>The path lists are separated using the character specified by the
           * {@code path.separator} system property, which defaults to {@code :}.
           *
           * @param dexPath the list of jar\/apk files containing classes and
           *     resources, delimited by {@code File.pathSeparator}, which
           *     defaults to {@code \":\"} on Android
           * @param optimizedDirectory this parameter is deprecated and has no effect
           * @param librarySearchPath the list of directories containing native
           *     libraries, delimited by {@code File.pathSeparator}; may be
           *     {@code null}
           * @param parent the parent class loader
           *\/
          public DexClassLoader(String dexPath, String optimizedDirectory,
                  String librarySearchPath, ClassLoader parent) {
              super(dexPath, null, librarySearchPath, parent);
          }
      }<\/pre>\n\n\n\n
      MyDexClassLoader\u52a0\u8f7dAPK:<\/p>\n\n\n\n
      Object layerP = new MyDexClassLoader(this, dexPath, cc.getFilesDir().getAbsolutePath(),
              (ClassLoader) sm.get()); <\/pre>\n\n\n\n
      \u4f7f\u7528loadClass\u52a0\u8f7dMyDexClassLoader\u7684class ,<\/p>\n\n\n\n
      getClassLoader().loadClass(MyConfig.APK2_ACTIVITY_MAIN);<\/pre>\n\n\n\n
      \u771f\u5b9e\u8c03\u7528\u5230ClassLoader\u7684loadClass<\/p>\n\n\n\n
      \u4e00\u4e2a\u95ee\u9898<\/h2>\n\n\n\n
      \u5728\u4f7f\u7528MyDexClassLoader \u524d\uff1a<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \u4f7f\u7528MyDexClassLoader\u540e\uff1a<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \u83ab\u975e\u8fd9\u4e2agetClassLoader\u8fd4\u56de\u7684ClassLoader \u4f1a\u53d8\u5316\u5417\uff1f<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      getClassLoader \u5b98\u7f51\u4ecb\u7ecd\u8fd4\u56de\u7c7b\u7684\u52a0\u8f7d\u5668\uff0c\u7c7b\u6ca1\u53d8\uff0c\u7c7b\u52a0\u8f7d\u5668\u6ca1\u53d8\uff0c\u4f46\u662f\u7c7b\u52a0\u8f7d\u7684\u7ee7\u627f\u5173\u7cfb\u53d8\u4e86\u3002\u3002\u3002\u6709\u70b9\u610f\u601d \u3002<\/p>\n\n\n\n
      https:\/\/developer.android.com\/reference\/java\/lang\/Class#getClassLoader()<\/a><\/p><\/blockquote>\n\n\n\n
      \u5de7\u7684\u662f\uff0c\u521a\u597d\u51fa\u73b0\u4e86\u4e24\u4e2a\u7ee7\u627f\u5173\u7cfb\u3002<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \u8fd9\u91cc\u7528getClassLoader.loadClass(“com.catherine.resource1.MainActivity”)\u6216\u8005<\/p>\n\n\n\n
      getClassLoader.getParent().loadClass(“com.catherine.resource1.MainActivity”)\u90fd\u6210\u529fload\u5230\u4e86\u76ee\u6807\u7c7b\u3002<\/p>\n\n\n\n
      \u4e14\u90fd\u8c03\u7528\u5230MyDexClassLoader\u7684loadClasss\u65b9\u6cd5, \u7b26\u5408\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\uff0c<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \"\"\/<\/figure>\n\n\n\n
      \u53e6\u4e00\u4e2a\u95ee\u9898<\/h2>\n\n\n\n
      class \u52a0\u8f7d\u6d41\u7a0b\u5462\uff1f<\/p>\n\n\n\n
      \u660e\u786e\u7ee7\u627f\u5173\u7cfb MyDexClassLoader.getParent == BootClassLoader<\/p>\n\n\n\n
      \u5728demo\u4e2dMyDexClassLoader\u4e2d\u8c03\u7528getParent\u65b9\u6cd5\u76f4\u63a5\u8fd4\u56de\u4e86BootClassLoader\uff0c<\/p>\n\n\n\n
      \"\"\/<\/figure>\n\n\n\n
      \u56e0\u4e3a\u7528\u7ee7\u627f\u5173\u7cfb\u65f6\u7ed9\u7684\u53c2\u6570\u5c31\u662fBootClassLoader\u3002<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      https:\/\/blog.csdn.net\/mr_liabill\/article\/details\/50497055<\/a><\/p><\/blockquote>\n\n\n\n
      \u53c2\u8003\u94fe\u63a5\u5f97\u77e5\uff0c \u53cc\u4eb2\u59d4\u6d3e\u5173\u7cfb\u5728\u52a0\u8f7d\u7c7b\u65f6(loadClass) , \u5148\u68c0\u6d4b\u662f\u5426\u5df2\u7ecf\u52a0\u8f7d\u8fc7\u4e86\uff0c\u6ca1\u6709\u52a0\u8f7d\u8fc7\uff0c \u518d\u4ea4\u7ed9\u7236\u7c7b\u52a0\u8f7d\uff1f \uff0c\u4f46\u662f\u8fd9\u91cc\u662fbootClassLoader\u80fd\u662f\u7531\u5b83\u6765\u52a0\u8f7d\u5417\uff0c\u5b83\u52a0\u8f7d\u7684\u8bdd\uff0c\u4e0d\u5c31\u6240\u6709\u7684ClassLoader\u90fd\u53ef\u4ee5\u7528\u4e86\u5417\uff1f\u6000\u7591\u53ef\u80fd\u8fd8\u662f\u6709\u8def\u5f84\u7684\u9650\u5236\u3002<\/p>\n\n\n\n
      https:\/\/github.com\/huanzhiyazi\/articles\/issues\/30<\/a><\/p><\/blockquote>\n\n\n\n
      \u8fd9\u8fd8\u6709\u4e00\u7bc7\u6bd4\u8f83\u597d\u7684\u6587\u7ae0\u8bb2\u8fd9\u4e2a\u53cc\u4eb2\u59d4\u6258\u673a\u5236\uff0c\u4f46\u662f\u4e5f\u6ca1\u6709\u56de\u7b54android \u53cc\u4eb2\u59d4\u6d3e\u7684\u52a0\u8f7d\u6d41\u7a0b\u3002<\/p>\n\n\n\n
      \u53ef\u80fd\u5f97\u518d\u770b\u4e0b\u3002<\/p>\n\n\n\n
      \u518d\u6765\u4e00\u4e2a\u95ee\u9898<\/h2>\n\n\n\n
      \u7528\u9ed8\u8ba4ClassLoader\u52a0\u8f7djava.lang.String \u6309\u7167\u6211\u4eec\u7684\u7406\u89e3\uff0c<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      \u4f46\u662f\u5b9e\u9645\u4e0a\u6211\u4eec\u7528loadClass\uff0c<\/p>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      <\/p>\n\n\n\n
      \u76f4\u63a5\u5c31\u8fdb\u884c\u4e86\u8fd4\u56de\uff0c\u751a\u81f3\u6ca1\u6709\u8d70\u5230MyDexClassLoader\uff0c\uff1f\uff1f\uff1f\uff1f<\/p>\n\n\n\n
      \u53ea\u80fd\u8bf4\u7b97\u662f\u521d\u6b65\u4e86\u89e3\u53cc\u4eb2\u59d4\u6d3e\u6a21\u578b\uff0c \u540e\u7eed\u719f\u7ec3android\u5e95\u5c42\u8c03\u8bd5\u540e\uff0c\u518d\u5f00\u5c55\u66f4\u7ec6\u8282\u7684\u7814\u7a76\u3002<\/p>\n\n\n\n
      \u6000\u7591\u7f13\u5b58<\/p>\n\n\n\n
      ART – Dex\u52a0\u8f7d\u6d41\u7a0b<\/h1>\n\n\n\n
      \"\"<\/figure>\n\n\n\n
      ART – \u5b57\u8282\u7801\u52a0\u8f7d\u6d41\u7a0b<\/h1>\n\n\n\n
      <\/p>\n","protected":false},"excerpt":{"rendered":"
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