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Commit e032061d authored by Torne (Richard Coles)'s avatar Torne (Richard Coles)
Browse files

Use new app preload path for WebView zygote. 

In the "common" case where the WebView stub is not being used, have the
WebView zygote use the new APK preload path added for the app zygote,
which avoids duplicating logic from the framework to construct the
classpath. This allows the WebView implementation to use a static shared
library, which was not previously possible.

The old codepath is retained for now to keep the WebView stub working
when it's in use, as it requires the special mechanism to override the
classloader cache key, but this can be removed when we no longer require
the stub.

Bug: 110790153
Test: Manual verification of classloader cache state
Change-Id: Ie49e5810d570bae7bec0341753e6c50d081189b5
parent 070aba8e

core/java/android/webkit/WebViewZygote.java

+29 −27
Original line number Diff line number Diff line
@@ -150,6 +150,7 @@ public class WebViewZygote { 
        }



        try {

            String abi = sPackage.applicationInfo.primaryCpuAbi;

            sZygote = Process.ZYGOTE_PROCESS.startChildZygote(

                    "com.android.internal.os.WebViewZygoteInit",

                    "webview_zygote",
@@ -158,18 +159,21 @@ public class WebViewZygote { 
                    null,  // gids

                    0,  // runtimeFlags

                    "webview_zygote",  // seInfo

                    sPackage.applicationInfo.primaryCpuAbi,  // abi

                    abi,  // abi

                    TextUtils.join(",", Build.SUPPORTED_ABIS),

                    null, // instructionSet

                    Process.FIRST_ISOLATED_UID,

                    Process.LAST_ISOLATED_UID);

            ZygoteProcess.waitForConnectionToZygote(sZygote.getPrimarySocketAddress());



            // All the work below is usually done by LoadedApk, but the zygote can't talk to

            // PackageManager or construct a LoadedApk since it's single-threaded pre-fork, so

            // doesn't have an ActivityThread and can't use Binder.

            // Instead, figure out the paths here, in the system server where we have access to

            // the package manager. Reuse the logic from LoadedApk to determine the correct

            // paths and pass them to the zygote as strings.

            if (sPackageOriginalAppInfo.sourceDir.equals(sPackage.applicationInfo.sourceDir)) {

                // No stub WebView is involved here, so we can preload the package the "clean" way

                // using the ApplicationInfo.

                sZygote.preloadApp(sPackage.applicationInfo, abi);

            } else {

                // Legacy path to support the stub WebView.

                // Reuse the logic from LoadedApk to determine the correct paths and pass them to

                // the zygote as strings.

                final List<String> zipPaths = new ArrayList<>(10);

                final List<String> libPaths = new ArrayList<>(10);

                LoadedApk.makePaths(null, false, sPackage.applicationInfo, zipPaths, libPaths);
@@ -179,18 +183,16 @@ public class WebViewZygote { 


                String libFileName = WebViewFactory.getWebViewLibrary(sPackage.applicationInfo);



            // In the case where the ApplicationInfo has been modified by the stub WebView,

            // we need to use the original ApplicationInfo to determine what the original classpath

            // would have been to use as a cache key.

                // Use the original ApplicationInfo to determine what the original classpath would

                // have been to use as a cache key.

                LoadedApk.makePaths(null, false, sPackageOriginalAppInfo, zipPaths, null);

                final String cacheKey = (zipPaths.size() == 1) ? zipPaths.get(0) :

                        TextUtils.join(File.pathSeparator, zipPaths);



            ZygoteProcess.waitForConnectionToZygote(sZygote.getPrimarySocketAddress());



                Log.d(LOGTAG, "Preloading package " + zip + " " + librarySearchPath);

                sZygote.preloadPackageForAbi(zip, librarySearchPath, libFileName, cacheKey,

                                             Build.SUPPORTED_ABIS[0]);

            }

        } catch (Exception e) {

            Log.e(LOGTAG, "Error connecting to webview zygote", e);

            stopZygoteLocked();

core/java/com/android/internal/os/WebViewZygoteInit.java

+40 −7
Original line number Diff line number Diff line
@@ -17,8 +17,9 @@ 
package com.android.internal.os;



import android.app.ApplicationLoaders;

import android.app.LoadedApk;

import android.content.pm.ApplicationInfo;

import android.net.LocalSocket;

import android.os.Build;

import android.text.TextUtils;

import android.util.Log;

import android.webkit.WebViewFactory;
@@ -65,6 +66,34 @@ class WebViewZygoteInit { 
            return true;

        }



        @Override

        protected boolean canPreloadApp() {

            return true;

        }



        @Override

        protected void handlePreloadApp(ApplicationInfo appInfo) {

            Log.i(TAG, "Beginning application preload for " + appInfo.packageName);

            LoadedApk loadedApk = new LoadedApk(null, appInfo, null, null, false, true, false);

            ClassLoader loader = loadedApk.getClassLoader();

            doPreload(loader, WebViewFactory.getWebViewLibrary(appInfo));



            // Add the APK to the Zygote's list of allowed files for children.

            Zygote.nativeAllowFileAcrossFork(appInfo.sourceDir);

            if (appInfo.splitSourceDirs != null) {

                for (String path : appInfo.splitSourceDirs) {

                    Zygote.nativeAllowFileAcrossFork(path);

                }

            }

            if (appInfo.sharedLibraryFiles != null) {

                for (String path : appInfo.sharedLibraryFiles) {

                    Zygote.nativeAllowFileAcrossFork(path);

                }

            }



            Log.i(TAG, "Application preload done");

        }



        @Override

        protected void handlePreloadPackage(String packagePath, String libsPath, String libFileName,

                String cacheKey) {
@@ -76,16 +105,22 @@ class WebViewZygoteInit { 
            ClassLoader loader = ApplicationLoaders.getDefault().createAndCacheWebViewClassLoader(

                    packagePath, libsPath, cacheKey);



            // Load the native library using WebViewLibraryLoader to share the RELRO data with other

            // processes.

            WebViewLibraryLoader.loadNativeLibrary(loader, libFileName);



            // Add the APK to the Zygote's list of allowed files for children.

            String[] packageList = TextUtils.split(packagePath, File.pathSeparator);

            for (String packageEntry : packageList) {

                Zygote.nativeAllowFileAcrossFork(packageEntry);

            }



            doPreload(loader, libFileName);



            Log.i(TAG, "Package preload done");

        }



        private void doPreload(ClassLoader loader, String libFileName) {

            // Load the native library using WebViewLibraryLoader to share the RELRO data with other

            // processes.

            WebViewLibraryLoader.loadNativeLibrary(loader, libFileName);



            // Once we have the classloader, look up the WebViewFactoryProvider implementation and

            // call preloadInZygote() on it to give it the opportunity to preload the native library

            // and perform any other initialisation work that should be shared among the children.
@@ -114,8 +149,6 @@ class WebViewZygoteInit { 
            } catch (IOException ioe) {

                throw new IllegalStateException("Error writing to command socket", ioe);

            }



            Log.i(TAG, "Package preload done");

        }

    }