内容简介:判断一下 dexList 和 classLoader如果 TinkerLoadVerifyFlag 为 true 的话,会对每个 dex 进行 md5 校验如果是 art 虚拟机并且是 Android N 及以上的环境,会另外加上 tinker_classN.apk
判断一下 dexList 和 classLoader
if (loadDexList.isEmpty() && classNDexInfo.isEmpty()) { Log.w(TAG, "there is no dex to load"); return true; } PathClassLoader classLoader = (PathClassLoader) TinkerDexLoader.class.getClassLoader(); if (classLoader != null) { Log.i(TAG, "classloader: " + classLoader.toString()); } else { Log.e(TAG, "classloader is null"); ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_DEX_CLASSLOADER_NULL); return false; }
如果 TinkerLoadVerifyFlag 为 true 的话,会对每个 dex 进行 md5 校验
String dexPath = directory + "/" + DEX_PATH + "/"; ArrayList<File> legalFiles = new ArrayList<>(); for (ShareDexDiffPatchInfo info : loadDexList) { //for dalvik, ignore art support dex // 对于 dalvik 虚拟机,忽略 art support dex if (isJustArtSupportDex(info)) { continue; } String path = dexPath + info.realName; File file = new File(path); if (application.isTinkerLoadVerifyFlag()) { long start = System.currentTimeMillis(); String checkMd5 = getInfoMd5(info); // 校验dex文件的 md5 值 if (!SharePatchFileUtil.verifyDexFileMd5(file, checkMd5)) { //it is good to delete the mismatch file ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_DEX_MD5_MISMATCH); intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_MISMATCH_DEX_PATH, file.getAbsolutePath()); return false; } Log.i(TAG, "verify dex file:" + file.getPath() + " md5, use time: " + (System.currentTimeMillis() - start)); } // dex文件都通过的话,加入到 legalFiles 集合中 legalFiles.add(file); }
如果是 art 虚拟机并且是 Android N 及以上的环境,会另外加上 tinker_classN.apk
// verify merge classN.apk if (isVmArt && !classNDexInfo.isEmpty()) { File classNFile = new File(dexPath + ShareConstants.CLASS_N_APK_NAME); long start = System.currentTimeMillis(); if (application.isTinkerLoadVerifyFlag()) { for (ShareDexDiffPatchInfo info : classNDexInfo) { if (!SharePatchFileUtil.verifyDexFileMd5(classNFile, info.rawName, info.destMd5InArt)) { ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_DEX_MD5_MISMATCH); intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_MISMATCH_DEX_PATH, classNFile.getAbsolutePath()); return false; } } } Log.i(TAG, "verify dex file:" + classNFile.getPath() + " md5, use time: " + (System.currentTimeMillis() - start)); legalFiles.add(classNFile); }
如果用户是ART虚拟机并且做了OTA升级,那么在加载dex补丁的时候就会先把最近一次的补丁全部DexFile.loadDex一遍.这么做的原因是有些场景做了OTA后,oat的规则可能发生变化,在这种情况下去加载上个系统版本oat过的dex就会出现问题.
File optimizeDir = new File(directory + "/" + oatDir); if (isSystemOTA) { final boolean[] parallelOTAResult = {true}; final Throwable[] parallelOTAThrowable = new Throwable[1]; String targetISA; try { targetISA = ShareTinkerInternals.getCurrentInstructionSet(); } catch (Throwable throwable) { Log.i(TAG, "getCurrentInstructionSet fail:" + throwable); // try { // targetISA = ShareOatUtil.getOatFileInstructionSet(testOptDexFile); // } catch (Throwable throwable) { // don't ota on the front deleteOutOfDateOATFile(directory); intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_INTERPRET_EXCEPTION, throwable); ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_GET_OTA_INSTRUCTION_SET_EXCEPTION); return false; // } } deleteOutOfDateOATFile(directory); Log.w(TAG, "systemOTA, try parallel oat dexes, targetISA:" + targetISA); // change dir optimizeDir = new File(directory + "/" + INTERPRET_DEX_OPTIMIZE_PATH); // 对 dex 文件作 odex 处理 TinkerDexOptimizer.optimizeAll( legalFiles, optimizeDir, true, targetISA, new TinkerDexOptimizer.ResultCallback() { long start; @Override public void onStart(File dexFile, File optimizedDir) { start = System.currentTimeMillis(); Log.i(TAG, "start to optimize dex:" + dexFile.getPath()); } @Override public void onSuccess(File dexFile, File optimizedDir, File optimizedFile) { // Do nothing. Log.i(TAG, "success to optimize dex " + dexFile.getPath() + ", use time " + (System.currentTimeMillis() - start)); } @Override public void onFailed(File dexFile, File optimizedDir, Throwable thr) { parallelOTAResult[0] = false; parallelOTAThrowable[0] = thr; Log.i(TAG, "fail to optimize dex " + dexFile.getPath() + ", use time " + (System.currentTimeMillis() - start)); } } ); if (!parallelOTAResult[0]) { Log.e(TAG, "parallel oat dexes failed"); intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_INTERPRET_EXCEPTION, parallelOTAThrowable[0]); ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_OTA_INTERPRET_ONLY_EXCEPTION); return false; } }
加载dex
try { SystemClassLoaderAdder.installDexes(application, classLoader, optimizeDir, legalFiles); } catch (Throwable e) { Log.e(TAG, "install dexes failed"); // e.printStackTrace(); intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_EXCEPTION, e); ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_DEX_LOAD_EXCEPTION); return false; } return true;
SystemClassLoaderAdder.installDexes
public static void installDexes(Application application, PathClassLoader loader, File dexOptDir, List<File> files) throws Throwable { Log.i(TAG, "installDexes dexOptDir: " + dexOptDir.getAbsolutePath() + ", dex size:" + files.size()); if (!files.isEmpty()) { files = createSortedAdditionalPathEntries(files); ClassLoader classLoader = loader; if (Build.VERSION.SDK_INT >= 24 && !checkIsProtectedApp(files)) { classLoader = AndroidNClassLoader.inject(loader, application); } //because in dalvik, if inner class is not the same classloader with it wrapper class. //it won't fail at dex2opt if (Build.VERSION.SDK_INT >= 23) { V23.install(classLoader, files, dexOptDir); } else if (Build.VERSION.SDK_INT >= 19) { V19.install(classLoader, files, dexOptDir); } else if (Build.VERSION.SDK_INT >= 14) { V14.install(classLoader, files, dexOptDir); } else { V4.install(classLoader, files, dexOptDir); } //install done sPatchDexCount = files.size(); Log.i(TAG, "after loaded classloader: " + classLoader + ", dex size:" + sPatchDexCount); if (!checkDexInstall(classLoader)) { //reset patch dex SystemClassLoaderAdder.uninstallPatchDex(classLoader); throw new TinkerRuntimeException(ShareConstants.CHECK_DEX_INSTALL_FAIL); } } }
可以看到,在加载 dex 的时候,分别分成了四个版本:
- v4
- v14
- v19
- v23
其中如果是 SDK 24 及以上,需要改造一下 classloder
针对每个版本不同的源码,进行 dex 插入
我们就来看其中一个版本 v19
private static final class V19 { private static void install(ClassLoader loader, List<File> additionalClassPathEntries, File optimizedDirectory) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, InvocationTargetException, NoSuchMethodException, IOException { /* The patched class loader is expected to be a descendant of * dalvik.system.BaseDexClassLoader. We modify its * dalvik.system.DexPathList pathList field to append additional DEX * file entries. */ Field pathListField = ShareReflectUtil.findField(loader, "pathList"); Object dexPathList = pathListField.get(loader); ArrayList<IOException> suppressedExceptions = new ArrayList<IOException>(); ShareReflectUtil.expandFieldArray(dexPathList, "dexElements", makeDexElements(dexPathList, new ArrayList<File>(additionalClassPathEntries), optimizedDirectory, suppressedExceptions)); if (suppressedExceptions.size() > 0) { for (IOException e : suppressedExceptions) { Log.w(TAG, "Exception in makeDexElement", e); throw e; } } } /** * A wrapper around * {@code private static final dalvik.system.DexPathList#makeDexElements}. */ private static Object[] makeDexElements( Object dexPathList, ArrayList<File> files, File optimizedDirectory, ArrayList<IOException> suppressedExceptions) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { Method makeDexElements = null; try { makeDexElements = ShareReflectUtil.findMethod(dexPathList, "makeDexElements", ArrayList.class, File.class, ArrayList.class); } catch (NoSuchMethodException e) { Log.e(TAG, "NoSuchMethodException: makeDexElements(ArrayList,File,ArrayList) failure"); // 对不同的 rom 做兼容,有的 rom 的 makeDexElements 方法参数类型是 List try { makeDexElements = ShareReflectUtil.findMethod(dexPathList, "makeDexElements", List.class, File.class, List.class); } catch (NoSuchMethodException e1) { Log.e(TAG, "NoSuchMethodException: makeDexElements(List,File,List) failure"); throw e1; } } return (Object[]) makeDexElements.invoke(dexPathList, files, optimizedDirectory, suppressedExceptions); } }
首先反射拿到反射得到 PathClassLoader 中的 pathList 对象,再将补丁文件通过反射调用makeDexElements 得到补丁文件的 Element[] ,再将补丁包的 Element[] 数组插入到 dexElements 中
另外,需要对 Android 7.0 及以上单独处理一下,具体看 Android N混合编译与对热补丁影响解析
加载补丁操作做好之后,最后还要检查一下,如果没加载成功就会执行卸载:
if (!checkDexInstall(classLoader)) { //reset patch dex SystemClassLoaderAdder.uninstallPatchDex(classLoader); throw new TinkerRuntimeException(ShareConstants.CHECK_DEX_INSTALL_FAIL); }
具体验证补丁是否加载成功的方法就是判断 TinkerTestDexLoad.isPatch 的值。
在没有补丁加载的情况下都是返回 false 的, 在补丁中修改 isPatch 属性为 true 。所以只要反射拿到isPatch 的属性为 true 就说明补丁已经成功加载进来了。否则就调用 SystemClassLoaderAdder.uninstallPatchDex 执行卸载
public static void uninstallPatchDex(ClassLoader classLoader) throws Throwable { if (sPatchDexCount <= 0) { return; } if (Build.VERSION.SDK_INT >= 14) { Field pathListField = ShareReflectUtil.findField(classLoader, "pathList"); Object dexPathList = pathListField.get(classLoader); ShareReflectUtil.reduceFieldArray(dexPathList, "dexElements", sPatchDexCount); } else { ShareReflectUtil.reduceFieldArray(classLoader, "mPaths", sPatchDexCount); ShareReflectUtil.reduceFieldArray(classLoader, "mFiles", sPatchDexCount); ShareReflectUtil.reduceFieldArray(classLoader, "mZips", sPatchDexCount); try { ShareReflectUtil.reduceFieldArray(classLoader, "mDexs", sPatchDexCount); } catch (Exception e) { } } }
卸载补丁可以说是加载补丁的逆向操作,具体操作可以分成 v4 和 v14 两个版本
具体的内容就是把 dexElements 中的头部 element 去除了。
以上所述就是小编给大家介绍的《Tinker源码分析(三):加载dex补丁流程》,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对 码农网 的支持!
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