Android6.0 PackageManagerService dex优化
2016-11-29 16:14
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主要是调用了PackageDexOptimizer.performDexOpt函数,这个函数又继续调用了performDexOptLI函数
上面这个函数遍历apk所有的代码路径,根据解析得到dexoptType,最后用installd来完成dexopt工作。
其中还有一个当dexoptType为dex2oat时,会调用createOatDirIfSupported来得到oatdir,其他情况oatdir为空了。
createOatDirIfSupported函数也是codePath如果是目录,就用Installd在该目录下创建一个目录,如果是apk文件直接返回空。
最后我们再来看下Installd的dexopt函数,先会根据oat_dir是否为空,如果不为空判断是否有效,然后也会根据这个oat_dir计算这个out_path,没有oat_dir就会调用create_cache_path函数来计算out_path。
calculate_oat_file_path函数就会根据oat_dir等来生成out_path.
没有oat_dir就会调用create_cache_path函数来计算out_path,最后会在DALVIK_CACHE_PREFIX目录下创建,而这个目录就是/data/dalvik-cache/,也就是最终会在这个目录下生成dex文件。
继续分析dexopt函数,根据dexopt类型来看源文件,一般是apk文件
后面就是打开文件,然后fork进程,调用run_dex2oat函数来执行。我们就不分析了
root@lc1861evb_arm64:/data/app/com.moji.mjweather-1/oat/arm # ls
base.odex
一、代码
Android6.0 PackageManagerService dex优化是在scanPackageDirtyLI函数中,代码如下:if ((scanFlags & SCAN_NO_DEX) == 0) { int result = mPackageDexOptimizer.performDexOpt(pkg, null /* instruction sets */, forceDex, (scanFlags & SCAN_DEFER_DEX) != 0, false /* inclDependencies */, (scanFlags & SCAN_BOOTING) == 0); if (result == PackageDexOptimizer.DEX_OPT_FAILED) { throw new PackageManagerException(INSTALL_FAILED_DEXOPT, "scanPackageLI"); } }
主要是调用了PackageDexOptimizer.performDexOpt函数,这个函数又继续调用了performDexOptLI函数
private int performDexOptLI(PackageParser.Package pkg, String[] targetInstructionSets, boolean forceDex, boolean defer, boolean bootComplete, ArraySet<String> done) { final String[] instructionSets = targetInstructionSets != null ? targetInstructionSets : getAppDexInstructionSets(pkg.applicationInfo); if (done != null) { done.add(pkg.packageName); if (pkg.usesLibraries != null) {//是否有一些共享库的apk也要dex优化 performDexOptLibsLI(pkg.usesLibraries, instructionSets, forceDex, defer, bootComplete, done); } if (pkg.usesOptionalLibraries != null) { performDexOptLibsLI(pkg.usesOptionalLibraries, instructionSets, forceDex, defer, bootComplete, done); } } if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_HAS_CODE) == 0) {//没有代码的pkg直接跳过 return DEX_OPT_SKIPPED; } final boolean vmSafeMode = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_VM_SAFE_MODE) != 0; final boolean debuggable = (pkg.applicationInfo.flags & ApplicationInfo.FLAG_DEBUGGABLE) != 0; final List<String> paths = pkg.getAllCodePathsExcludingResourceOnly(); boolean performedDexOpt = false; // There are three basic cases here: // 1.) we need to dexopt, either because we are forced or it is needed // 2.) we are deferring a needed dexopt // 3.) we are skipping an unneeded dexopt final String[] dexCodeInstructionSets = getDexCodeInstructionSets(instructionSets); for (String dexCodeInstructionSet : dexCodeInstructionSets) { if (!forceDex && pkg.mDexOptPerformed.contains(dexCodeInstructionSet)) {//没有强制或者已经dex优化过直接continue continue; } for (String path : paths) {//遍历所有代码路径 final int dexoptNeeded; if (forceDex) { dexoptNeeded = DexFile.DEX2OAT_NEEDED; } else { try { dexoptNeeded = DexFile.getDexOptNeeded(path, pkg.packageName, dexCodeInstructionSet, defer); } catch (IOException ioe) { Slog.w(TAG, "IOException reading apk: " + path, ioe); return DEX_OPT_FAILED; } } if (!forceDex && defer && dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) { // We're deciding to defer a needed dexopt. Don't bother dexopting for other // paths and instruction sets. We'll deal with them all together when we process // our list of deferred dexopts. addPackageForDeferredDexopt(pkg); return DEX_OPT_DEFERRED; } if (dexoptNeeded != DexFile.NO_DEXOPT_NEEDED) { final String dexoptType; String oatDir = null; if (dexoptNeeded == DexFile.DEX2OAT_NEEDED) { dexoptType = "dex2oat";//dex-opt类型 try { oatDir = createOatDirIfSupported(pkg, dexCodeInstructionSet);//获取otaDir } catch (IOException ioe) { Slog.w(TAG, "Unable to create oatDir for package: " + pkg.packageName); return DEX_OPT_FAILED; } } else if (dexoptNeeded == DexFile.PATCHOAT_NEEDED) { dexoptType = "patchoat"; } else if (dexoptNeeded == DexFile.SELF_PATCHOAT_NEEDED) { dexoptType = "self patchoat"; } else { throw new IllegalStateException("Invalid dexopt needed: " + dexoptNeeded); } Log.i(TAG, "Running dexopt (" + dexoptType + ") on: " + path + " pkg="//关键信息打印 + pkg.applicationInfo.packageName + " isa=" + dexCodeInstructionSet + " vmSafeMode=" + vmSafeMode + " debuggable=" + debuggable + " oatDir = " + oatDir + " bootComplete=" + bootComplete); final int sharedGid = UserHandle.getSharedAppGid(pkg.applicationInfo.uid); final int ret = mPackageManagerService.mInstaller.dexopt(path, sharedGid,//调用installd的dexopt !pkg.isForwardLocked(), pkg.packageName, dexCodeInstructionSet, dexoptNeeded, vmSafeMode, debuggable, oatDir, bootComplete); // Dex2oat might fail due to compiler / verifier errors. We soldier on // regardless, and attempt to interpret the app as a safety net. if (ret == 0) {//Installd dexopt成功了 performedDexOpt = true; } } } // At this point we haven't failed dexopt and we haven't deferred dexopt. We must // either have either succeeded dexopt, or have had getDexOptNeeded tell us // it isn't required. We therefore mark that this package doesn't need dexopt unless // it's forced. performedDexOpt will tell us whether we performed dex-opt or skipped // it. pkg.mDexOptPerformed.add(dexCodeInstructionSet);//这代表已经处理过了 } // If we've gotten here, we're sure that no error occurred and that we haven't // deferred dex-opt. We've either dex-opted one more paths or instruction sets or // we've skipped all of them because they are up to date. In both cases this // package doesn't need dexopt any longer. return performedDexOpt ? DEX_OPT_PERFORMED : DEX_OPT_SKIPPED; }
上面这个函数遍历apk所有的代码路径,根据解析得到dexoptType,最后用installd来完成dexopt工作。
其中还有一个当dexoptType为dex2oat时,会调用createOatDirIfSupported来得到oatdir,其他情况oatdir为空了。
createOatDirIfSupported函数也是codePath如果是目录,就用Installd在该目录下创建一个目录,如果是apk文件直接返回空。
private String createOatDirIfSupported(PackageParser.Package pkg, String dexInstructionSet) throws IOException { if (!pkg.canHaveOatDir()) { return null; } File codePath = new File(pkg.codePath); if (codePath.isDirectory()) { File oatDir = getOatDir(codePath); mPackageManagerService.mInstaller.createOatDir(oatDir.getAbsolutePath(), dexInstructionSet); return oatDir.getAbsolutePath(); } return null; }
最后我们再来看下Installd的dexopt函数,先会根据oat_dir是否为空,如果不为空判断是否有效,然后也会根据这个oat_dir计算这个out_path,没有oat_dir就会调用create_cache_path函数来计算out_path。
int dexopt(const char *apk_path, uid_t uid, bool is_public, const char *pkgname, const char *instruction_set, int dexopt_needed, bool vm_safe_mode, bool debuggable, const char* oat_dir, bool boot_complete) { ...... // Early best-effort check whether we can fit the the path into our buffers. // Note: the cache path will require an additional 5 bytes for ".swap", but we'll try to run // without a swap file, if necessary. if (strlen(apk_path) >= (PKG_PATH_MAX - 8)) { ALOGE("apk_path too long '%s'\n", apk_path); return -1; } if (oat_dir != NULL && oat_dir[0] != '!') { if (validate_apk_path(oat_dir)) { ALOGE("invalid oat_dir '%s'\n", oat_dir); return -1; } if (calculate_oat_file_path(out_path, oat_dir, apk_path, instruction_set)) { return -1; } } else { if (create_cache_path(out_path, apk_path, instruction_set)) { return -1; } }
calculate_oat_file_path函数就会根据oat_dir等来生成out_path.
int calculate_oat_file_path(char path[PKG_PATH_MAX], const char *oat_dir, const char *apk_path, const char *instruction_set) { char *file_name_start; char *file_name_end; file_name_start = strrchr(apk_path, '/'); if (file_name_start == NULL) { ALOGE("apk_path '%s' has no '/'s in it\n", apk_path); return -1; } file_name_end = strrchr(apk_path, '.'); if (file_name_end < file_name_start) { ALOGE("apk_path '%s' has no extension\n", apk_path); return -1; } // Calculate file_name int file_name_len = file_name_end - file_name_start - 1; char file_name[file_name_len + 1]; memcpy(file_name, file_name_start + 1, file_name_len); file_name[file_name_len] = '\0'; // <apk_parent_dir>/oat/<isa>/<file_name>.odex snprintf(path, PKG_PATH_MAX, "%s/%s/%s.odex", oat_dir, instruction_set, file_name); return 0; }
没有oat_dir就会调用create_cache_path函数来计算out_path,最后会在DALVIK_CACHE_PREFIX目录下创建,而这个目录就是/data/dalvik-cache/,也就是最终会在这个目录下生成dex文件。
int create_cache_path(char path[PKG_PATH_MAX], const char *src, const char *instruction_set) { char *tmp; int srclen; int dstlen; srclen = strlen(src); /* demand that we are an absolute path */ if ((src == 0) || (src[0] != '/') || strstr(src,"..")) { return -1; } if (srclen > PKG_PATH_MAX) { // XXX: PKG_NAME_MAX? return -1; } dstlen = srclen + strlen(DALVIK_CACHE_PREFIX) + strlen(instruction_set) + strlen(DALVIK_CACHE_POSTFIX) + 2; if (dstlen > PKG_PATH_MAX) { return -1; } sprintf(path,"%s%s/%s%s", DALVIK_CACHE_PREFIX, instruction_set, src + 1, /* skip the leading / */ DALVIK_CACHE_POSTFIX); for(tmp = path + strlen(DALVIK_CACHE_PREFIX) + strlen(instruction_set) + 1; *tmp; tmp++) { if (*tmp == '/') { *tmp = '@'; } } return 0; }
继续分析dexopt函数,根据dexopt类型来看源文件,一般是apk文件
switch (dexopt_needed) { case DEXOPT_DEX2OAT_NEEDED: input_file = apk_path; break; case DEXOPT_PATCHOAT_NEEDED: if (!calculate_odex_file_path(in_odex_path, apk_path, instruction_set)) { return -1; } input_file = in_odex_path; break; case DEXOPT_SELF_PATCHOAT_NEEDED: input_file = out_path; break; default: ALOGE("Invalid dexopt needed: %d\n", dexopt_needed); exit(72); }
后面就是打开文件,然后fork进程,调用run_dex2oat函数来执行。我们就不分析了
二、实例
2.1 没有目录
最终如果你的apk没有目录,会在如下目录有classes.dex后缀的文件。root@lc1861evb_arm64:/data/dalvik-cache/arm # ls data@app@IflytekInput.apk@classes.dex data@app@NotePadPlus.apk@classes.dex
2.2 有目录
而有目录的,比如我们自己安装的墨迹天气,会有一个oat目录,最后有一个base.odex文件root@lc1861evb_arm64:/data/app/com.moji.mjweather-1/oat/arm # ls
base.odex
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