Android: Add chrome-specific dynamic linker.

content/public/android/java/src/org/chromium/content/app/ChildProcessService.java

Index: content/public/android/java/src/org/chromium/content/app/ChildProcessService.java
diff --git a/content/public/android/java/src/org/chromium/content/app/ChildProcessService.java b/content/public/android/java/src/org/chromium/content/app/ChildProcessService.java
index 3d85310926cb657db415002f0e5e2b7bc5eb8090..86461353d2de2efb3420daf6e16b47a20ff9c9d5 100644
--- a/content/public/android/java/src/org/chromium/content/app/ChildProcessService.java
+++ b/content/public/android/java/src/org/chromium/content/app/ChildProcessService.java
@@ -21,7 +21,6 @@ import org.chromium.base.JNINamespace;
 import org.chromium.content.browser.ChildProcessConnection;
 import org.chromium.content.common.IChildProcessCallback;
 import org.chromium.content.common.IChildProcessService;
-import org.chromium.content.browser.ChildProcessLauncher;
 import org.chromium.content.common.ProcessInitException;
 
 import java.util.ArrayList;
@@ -52,9 +51,13 @@ public class ChildProcessService extends Service {
     // Pairs IDs and file descriptors that should be registered natively.
     private ArrayList<Integer> mFileIds;
     private ArrayList<ParcelFileDescriptor> mFileFds;
+    // Linker-specific parameters for this child process service.
+    private LinkerParams mLinkerParams;
 
     private static AtomicReference<Context> sContext = new AtomicReference<Context>(null);
     private boolean mLibraryInitialized = false;
+    // Becomes true once the service is bound.
+    private boolean mIsBound = false;
 
     // Binder object used by clients for this service.
     private final IChildProcessService.Stub mBinder = new IChildProcessService.Stub() {
@@ -89,6 +92,11 @@ public class ChildProcessService extends Service {
                             + ChildProcessConnection.EXTRA_FILES_ID_SUFFIX;
                     mFileIds.add(args.getInt(idName));
                 }
+                Bundle sharedRelros = args.getBundle(Linker.EXTRA_LINKER_SHARED_RELROS);
+                if (sharedRelros != null) {
+                    Linker.useSharedRelros(sharedRelros);

[palmer, 2013/10/01 00:11:22]

How sure are we that only the browser could invoke this? I think this guarantees
it (from AndroidManifest.xml):

 12     <permission
android:name="com.google.android.apps.chrome.permission.CHILD_SERVICE"
 13         android:protectionLevel="signature" />

And then each SandboxedProcessService* requires callers to have this Permission.

That works for me, but I wanted to make sure it matches your intent.

[digit1, 2013/10/01 15:40:20]

Yes, this is part of the existing code for starting child processes, and if
anything could invoke it, there would be much more serious problems here.

+                    sharedRelros = null;
+                }
                 mMainThread.notifyAll();
             }
             return Process.myPid();
@@ -112,6 +120,18 @@ public class ChildProcessService extends Service {
             @Override
             public void run()  {
                 try {
+                    boolean useLinker = Linker.isUsed();
+
+                    if (useLinker) {
+                        synchronized (mMainThread) {
+                            while (!mIsBound)
+                                mMainThread.wait();
+                        }
+                        if (mLinkerParams != null && mLinkerParams.mWaitForSharedRelro)
+                            Linker.initServiceProcess(mLinkerParams.mBaseLoadAddress);
+                        else
+                            Linker.disableSharedRelros();
+                    }
                     try {
                         LibraryLoader.loadNow();
                     } catch (ProcessInitException e) {
@@ -188,6 +208,10 @@ public class ChildProcessService extends Service {
         synchronized (mMainThread) {
             mCommandLineParams = intent.getStringArrayExtra(
                     ChildProcessConnection.EXTRA_COMMAND_LINE);
+            mLinkerParams = null;
+            if (Linker.isUsed())
+                mLinkerParams = new LinkerParams(intent);
+            mIsBound = true;
             mMainThread.notifyAll();
         }