Fix a race condition determining whether password fallback mode is allowed.

The fix is in LockPatternKeyguardView, whose constructor was
firing off an asynchronous request to the AccountManager to
find out about the specifics of the account on the device.
(If it's SAML, we don't have the password in cleartext and
therefore can't use it to unlock.) Unfortunately, if the
AccountManager responds too quickly, we get the answer (in
LPKV.run()) before the UnlockScreen has even been
instantiated (later in LPKV's ctor).

The fix is to create the unlock screen first and *then* ping
the AccountManager for details.

Bug: http://b/2216308
Change-Id: Iedc84675c0ab8a001d062d806e2bee7ed1a29758

3 files changed, 39 insertions, 14 deletions

diff --git a/policy/com/android/internal/policy/impl/KeyguardViewManager.java b/policy/com/android/internal/policy/impl/KeyguardViewManager.java
index bac2fcad..d4dc429 100644
--- a/policy/com/android/internal/policy/impl/KeyguardViewManager.java
+++ b/policy/com/android/internal/policy/impl/KeyguardViewManager.java
@@ -92,7 +92,7 @@ public class KeyguardViewManager implements KeyguardWindowController {
      * lazily.
      */
     public synchronized void show() {
-        if (DEBUG) Log.d(TAG, "show()");
+        if (DEBUG) Log.d(TAG, "show(); mKeyguardView==" + mKeyguardView);
 
         if (mKeyguardHost == null) {
             if (DEBUG) Log.d(TAG, "keyguard host is null, creating it...");
diff --git a/policy/com/android/internal/policy/impl/LockPatternKeyguardView.java b/policy/com/android/internal/policy/impl/LockPatternKeyguardView.java
index 0ebd945..00dc929 100644
--- a/policy/com/android/internal/policy/impl/LockPatternKeyguardView.java
+++ b/policy/com/android/internal/policy/impl/LockPatternKeyguardView.java
@@ -160,7 +160,10 @@ public class LockPatternKeyguardView extends KeyguardViewBase
         } catch (AuthenticatorException e) {
         }
         mEnableFallback = !hasSAMLAccount;
-        if (mUnlockScreen instanceof UnlockScreen) {
+
+        if (mUnlockScreen == null) {
+            Log.w(TAG, "no unlock screen when receiving AccountManager information");
+        } else if (mUnlockScreen instanceof UnlockScreen) {
             ((UnlockScreen)mUnlockScreen).setEnableFallback(true);
         }
     }
@@ -179,18 +182,6 @@ public class LockPatternKeyguardView extends KeyguardViewBase
             KeyguardWindowController controller) {
         super(context);
 
-        final boolean hasAccount = AccountManager.get(context).getAccounts().length > 0;
-        if (hasAccount) {
-            /* If we have a SAML account which requires web login we can not use the
-             fallback screen UI to ask the user for credentials.
-             For now we will disable fallback screen in this case.
-             Ultimately we could consider bringing up a web login from GLS
-             but need to make sure that it will work in the "locked screen" mode. */
-            String[] features = new String[] {"saml"};
-            AccountManager.get(context).getAccountsByTypeAndFeatures(
-                    "com.google", features, this, null);
-        }
-        
         mEnableFallback = false;
 
         mRequiresSim =
@@ -275,6 +266,9 @@ public class LockPatternKeyguardView extends KeyguardViewBase
             public void reportFailedPatternAttempt() {
                 mUpdateMonitor.reportFailedAttempt();
                 final int failedAttempts = mUpdateMonitor.getFailedAttempts();
+                if (DEBUG) Log.d(TAG, 
+                    "reportFailedPatternAttempt: #" + failedAttempts +
+                    " (enableFallback=" + mEnableFallback + ")");
                 if (mEnableFallback && failedAttempts ==
                         (LockPatternUtils.FAILED_ATTEMPTS_BEFORE_RESET
                                 - LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT)) {
@@ -313,8 +307,28 @@ public class LockPatternKeyguardView extends KeyguardViewBase
         mLockScreen = createLockScreen();
         addView(mLockScreen);
         final UnlockMode unlockMode = getUnlockMode();
+        if (DEBUG) Log.d(TAG, 
+            "LockPatternKeyguardView ctor: about to createUnlockScreenFor; mEnableFallback="
+            + mEnableFallback);
         mUnlockScreen = createUnlockScreenFor(unlockMode);
         mUnlockScreenMode = unlockMode;
+
+        // Ask the account manager if we have an account that can be used as a
+        // fallback in case the user forgets his pattern. The response comes
+        // back in run() below; don't bother asking until you've called
+        // createUnlockScreenFor(), else the information will go unused.
+        final boolean hasAccount = AccountManager.get(context).getAccounts().length > 0;
+        if (hasAccount) {
+            /* If we have a SAML account which requires web login we can not use the
+             fallback screen UI to ask the user for credentials.
+             For now we will disable fallback screen in this case.
+             Ultimately we could consider bringing up a web login from GLS
+             but need to make sure that it will work in the "locked screen" mode. */
+            String[] features = new String[] {"saml"};
+            AccountManager.get(context).getAccountsByTypeAndFeatures(
+                    "com.google", features, this, null);
+        }
+
         addView(mUnlockScreen);
         updateScreen(mMode);
     }
@@ -475,6 +489,8 @@ public class LockPatternKeyguardView extends KeyguardViewBase
                     mUpdateMonitor,
                     mKeyguardScreenCallback,
                     mUpdateMonitor.getFailedAttempts());
+            if (DEBUG) Log.d(TAG,
+                "createUnlockScreenFor(" + unlockMode + "): mEnableFallback=" + mEnableFallback);
             view.setEnableFallback(mEnableFallback);
             return view;
         } else if (unlockMode == UnlockMode.SimPin) {
diff --git a/policy/com/android/internal/policy/impl/UnlockScreen.java b/policy/com/android/internal/policy/impl/UnlockScreen.java
index f85b62f..e413d6b 100644
--- a/policy/com/android/internal/policy/impl/UnlockScreen.java
+++ b/policy/com/android/internal/policy/impl/UnlockScreen.java
@@ -27,6 +27,7 @@ import android.widget.Button;
 import android.widget.TextView;
 import android.text.format.DateFormat;
 import android.text.TextUtils;
+import android.util.Log;
 import com.android.internal.R;
 import com.android.internal.telephony.IccCard;
 import com.android.internal.widget.LinearLayoutWithDefaultTouchRecepient;
@@ -45,6 +46,7 @@ class UnlockScreen extends LinearLayoutWithDefaultTouchRecepient
         implements KeyguardScreen, KeyguardUpdateMonitor.ConfigurationChangeCallback,
         KeyguardUpdateMonitor.InfoCallback, KeyguardUpdateMonitor.SimStateCallback {
 
+    private static final boolean DEBUG = false;
     private static final String TAG = "UnlockScreen";
 
     // how long before we clear the wrong pattern
@@ -162,6 +164,12 @@ class UnlockScreen extends LinearLayoutWithDefaultTouchRecepient
         mTotalFailedPatternAttempts = totalFailedAttempts;
         mFailedPatternAttemptsSinceLastTimeout = totalFailedAttempts % LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT;
 
+        if (DEBUG) Log.d(TAG,
+            "UnlockScreen() ctor: totalFailedAttempts="
+                 + totalFailedAttempts + ", mFailedPat...="
+                 + mFailedPatternAttemptsSinceLastTimeout 
+                 );
+
         if (mUpdateMonitor.isInPortrait()) {
             LayoutInflater.from(context).inflate(R.layout.keyguard_screen_unlock_portrait, this, true);
         } else {
@@ -239,6 +247,7 @@ class UnlockScreen extends LinearLayoutWithDefaultTouchRecepient
     }
 
     public void setEnableFallback(boolean state) {
+        if (DEBUG) Log.d(TAG, "setEnableFallback(" + state + ")");
         mEnableFallback = state;
     }