Skip direct map from apk check for pre-KitKat Samsung.

base/android/java/src/org/chromium/base/library_loader/Linker.java

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.base.library_loader;
 
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.ParcelFileDescriptor;
 import android.os.Parcelable;
 import android.util.Log;
 
 import org.chromium.base.AccessedByNative;
 import org.chromium.base.CalledByNative;
 import org.chromium.base.SysUtils;
 import org.chromium.base.ThreadUtils;
 
 import java.io.FileNotFoundException;
+import java.util.Arrays;
 import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Set;
 
 import javax.annotation.Nullable;
 
 /*
  * Technical note:
  *
  * The point of this class is to provide an alternative to System.loadLibrary()
  * to load native shared libraries. One specific feature that it supports is the
  * ability to save RAM by sharing the ELF RELRO sections between renderer
  * processes.
@@ skipping 151 matching lines @@
     //   NORMAL       -> This is not a low-memory device.
     public static final int MEMORY_DEVICE_CONFIG_INIT = 0;
     public static final int MEMORY_DEVICE_CONFIG_LOW = 1;
     public static final int MEMORY_DEVICE_CONFIG_NORMAL = 2;
 
     // Indicates if this is a low-memory device or not. The default is to
     // determine this by probing the system at runtime, but this can be forced
     // for testing by calling setMemoryDeviceConfig().
     private static int sMemoryDeviceConfig = MEMORY_DEVICE_CONFIG_INIT;
 
+    // List of devices for which we suppress the test for support for mapping
+    // the APK file with executable permission. This test triggers a warning
+    // on some devices. Devices must be listed in all uppercase only, on the
+    // working assumption that no two distinct actual devices would have model
+    // strings that differ only in character case.
+    //
+    // For more, see:
+    //   https://code.google.com/p/chromium/issues/detail?id=448084
+    private static final String[] MAP_CHECK_BLACKLIST = {
+            "SCH-P709", "GT-I9158", "GT-I9152", "GT-I9150", "GT-I9200X",
+            "SGH-M819N", "SCH-R960", "SPH-L600", "SGH-I527M", "SGH-I527",
+            "SCH-P729", "SHV-E310L", "SHV-E310S", "SHV-E310K", "GT-I9208",
+            "GT-I9205", "GT-I9200"};
+
+    // The blacklist is only used if the OS version code indicates that it
+    // pre-dates an expiry version code.
+    private static final int MAP_CHECK_BLACKLIST_EXPIRY =
+            android.os.Build.VERSION_CODES.KITKAT;

[Andrew Hayden (chromium.org), 2015/01/23 14:59:51]

I don't think you can use this on ICS, right? How do we deal with that?

[simonb (inactive), 2015/01/23 16:03:19]

Compile-time constants should be okay.  From:

http://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html

"If a primitive type or a string is defined as a constant and the value is known
at compile time, the compiler replaces the constant name everywhere in the code
with its value. This is called a compile-time constant."

+
+    // Lookup set, lazy-initialized from the MAP_CHECK_BLACKLIST array.
+    private static Set<String> sMapCheckBlacklist = null;
+
     // Becomes true after linker initialization.
     private static boolean sInitialized = false;
 
     // Set to true to indicate that the system supports safe sharing of RELRO sections.
     private static boolean sRelroSharingSupported = false;
 
     // Set to true if this runs in the browser process. Disabled by initServiceProcess().
     // TODO(petrcermak): This flag can be incorrectly set to false (even though this might run in
     // the browser process) on low-memory devices.
     private static boolean sInBrowserProcess = true;
@@ skipping 636 matching lines @@
 
     /**
      * Check whether the device supports mapping the APK file with executable permission.
      *
      * @param apkFile Filename of the APK.
      * @return true if supported.
      */
     public static boolean checkMapExecSupport(String apkFile) {
         assert apkFile != null;
 
-        // https://code.google.com/p/chromium/issues/detail?id=448084
-        // Do not check if the device is Samsung Mega.
+        // If the android build version is before a known good release, check
+        // the blacklist for the build model. If the model is listed then
+        // we skip the check for mmap exec support and return false. This avoids
+        // triggering a warning on these devices. The version check is included
+        // because these devices do not show the warning on later OS builds.
+        //
+        // Uses a case-insensitive lookup to ensure nothing is missed. No two
+        // devices will differ in model character case only. We ensure that the
+        // blacklist is populated with uppercased device names.
+        //
+        // For more, see:
+        //   https://code.google.com/p/chromium/issues/detail?id=448084
         final String model = android.os.Build.MODEL;
-        if (model != null && model.equals("GT-I9205")) {
-            if (DEBUG) Log.i(TAG, "checkMapExecSupport: model is '" + model
-                             + "', returning false");
-            return false;
+        final int version = android.os.Build.VERSION.SDK_INT;
+
+        if (model != null && version < MAP_CHECK_BLACKLIST_EXPIRY) {
+            synchronized (Linker.class) {
+                // Initialize the blacklist lookup set before first use.
+                if (sMapCheckBlacklist == null) {
+                    if (DEBUG) Log.i(TAG, "checkMapExecSupport: initializing blacklist");
+                    final List<String> list = Arrays.asList(MAP_CHECK_BLACKLIST);
+                    sMapCheckBlacklist = new HashSet<String>(list);
+                }
+            }
+
+            // Search the blacklist for the model reported by the OS.
+            if (sMapCheckBlacklist.contains(model.toUpperCase())) {
+                if (DEBUG) Log.i(TAG, "checkMapExecSupport: " + model
+                        + ": model is blacklisted, returning false");
+                return false;
+            }
         }
 
         synchronized (Linker.class) {
             ensureInitializedLocked();
 
             if (DEBUG) Log.i(TAG, "checkMapExecSupport: " + apkFile);
             boolean supported = nativeCheckMapExecSupport(apkFile);
             if (DEBUG) Log.i(TAG, "Mapping the APK file with executable permission "
                     + (supported ? "" : "NOT ") + "supported");
             return supported;
@@ skipping 277 matching lines @@
         }
     }
 
     // The map of libraries that are currently loaded in this process.
     private static HashMap<String, LibInfo> sLoadedLibraries = null;
 
     // Used to pass the shared RELRO Bundle through Binder.
     public static final String EXTRA_LINKER_SHARED_RELROS =
             "org.chromium.base.android.linker.shared_relros";
 }