Make sure to cleanup when timing out from a single scan

Also fix general failure cases

Bug: 26095183
Change-Id: I88433ff77c0adb4073350ae7a4746b5ee4da5033

2 files changed, 48 insertions, 37 deletions

diff --git a/service/java/com/android/server/wifi/SupplicantWifiScannerImpl.java b/service/java/com/android/server/wifi/SupplicantWifiScannerImpl.java
index 9cc685ffc..7e466a5e6 100644
--- a/service/java/com/android/server/wifi/SupplicantWifiScannerImpl.java
+++ b/service/java/com/android/server/wifi/SupplicantWifiScannerImpl.java
@@ -48,6 +48,9 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
     private static final String TAG = "SupplicantWifiScannerImpl";
     private static final boolean DBG = false;
 
+    public static final String BACKGROUND_PERIOD_ALARM_TAG = TAG + " Background Scan Period";
+    public static final String TIMEOUT_ALARM_TAG = TAG + " Scan Timeout";
+
     private static final int SCAN_BUFFER_CAPACITY = 10;
     private static final int MAX_APS_PER_SCAN = 32;
     private static final int MAX_SCAN_BUCKETS = 16;
@@ -94,6 +97,14 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
     private boolean mHwPnoRunning = false;
     private final boolean mHwPnoScanSupported;
 
+    /**
+     * Duration to wait before timing out a scan.
+     *
+     * The expected behavior is that the hardware will return a failed scan if it does not
+     * complete, but timeout just in case it does not.
+     */
+    private static final long SCAN_TIMEOUT_MS = 10000;
+
     AlarmManager.OnAlarmListener mScanPeriodListener = new AlarmManager.OnAlarmListener() {
             public void onAlarm() {
                 synchronized (mSettingsLock) {
@@ -102,6 +113,14 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
             }
         };
 
+    AlarmManager.OnAlarmListener mScanTimeoutListener = new AlarmManager.OnAlarmListener() {
+            public void onAlarm() {
+                synchronized (mSettingsLock) {
+                    handleScanTimeout();
+                }
+            }
+        };
+
     public SupplicantWifiScannerImpl(Context context, WifiNative wifiNative,
             ChannelHelper channelHelper, Looper looper) {
         mContext = context;
@@ -292,6 +311,12 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
         }
     }
 
+    private void handleScanTimeout() {
+        Log.e(TAG, "Timed out waiting for scan result from supplicant");
+        reportScanFailure();
+        processPendingScans();
+    }
+
     private void processPendingScans() {
         synchronized (mSettingsLock) {
             // Wait for the active scan result to come back to reschedule other scans,
@@ -366,8 +391,7 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
                     mBackgroundScanPeriodPending = false;
                     mAlarmManager.set(AlarmManager.RTC_WAKEUP,
                             System.currentTimeMillis() + mBackgroundScanSettings.base_period_ms,
-                            "SupplicantWifiScannerImpl Period",
-                            mScanPeriodListener, mEventHandler);
+                            BACKGROUND_PERIOD_ALARM_TAG, mScanPeriodListener, mEventHandler);
                 }
             }
 
@@ -409,6 +433,9 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
                             + ", background=" + newScanSettings.backgroundScanActive
                             + ", single=" + newScanSettings.singleScanActive);
                     mLastScanSettings = newScanSettings;
+                    mAlarmManager.set(AlarmManager.RTC_WAKEUP,
+                            System.currentTimeMillis() + SCAN_TIMEOUT_MS,
+                            TIMEOUT_ALARM_TAG, mScanTimeoutListener, mEventHandler);
                 } else {
                     Log.e(TAG, "Failed to start scan, freqs=" + freqs);
                     // indicate scan failure async
@@ -421,7 +448,7 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
                                 }
                             }
                         });
-                    // TODO if scans fail enough background scans should be failed as well
+                    // TODO(b/27769665) background scans should be failed too if scans fail enough
                 }
             } else if (isHwPnoScanRequired()) {
                 newScanSettings.setHwPnoScan(mPnoEventHandler);
@@ -454,14 +481,13 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
     public boolean handleMessage(Message msg) {
         switch(msg.what) {
             case WifiMonitor.SCAN_FAILED_EVENT:
-                // TODO indicate failure to caller
                 Log.w(TAG, "Scan failed");
-                synchronized (mSettingsLock) {
-                    mLastScanSettings = null;
-                }
+                mAlarmManager.cancel(mScanTimeoutListener);
+                reportScanFailure();
                 processPendingScans();
                 break;
             case WifiMonitor.SCAN_RESULTS_EVENT:
+                mAlarmManager.cancel(mScanTimeoutListener);
                 pollLatestScanData();
                 processPendingScans();
                 break;
@@ -471,6 +497,19 @@ public class SupplicantWifiScannerImpl extends WifiScannerImpl implements Handle
         return true;
     }
 
+    private void reportScanFailure() {
+        synchronized (mSettingsLock) {
+            if (mLastScanSettings != null) {
+                if (mLastScanSettings.singleScanEventHandler != null) {
+                    mLastScanSettings.singleScanEventHandler
+                            .onScanStatus(WifiNative.WIFI_SCAN_FAILED);
+                }
+                // TODO(b/27769665) background scans should be failed too if scans fail enough
+                mLastScanSettings = null;
+            }
+        }
+    }
+
     private void pollLatestScanData() {
         synchronized (mSettingsLock) {
             if (mLastScanSettings == null) {
diff --git a/service/java/com/android/server/wifi/WifiScanningServiceImpl.java b/service/java/com/android/server/wifi/WifiScanningServiceImpl.java
index 98b4e1e78..0dc6ad733 100644
--- a/service/java/com/android/server/wifi/WifiScanningServiceImpl.java
+++ b/service/java/com/android/server/wifi/WifiScanningServiceImpl.java
@@ -40,7 +40,6 @@ import android.os.Looper;
 import android.os.Message;
 import android.os.Messenger;
 import android.os.RemoteException;
-import android.os.SystemClock;
 import android.os.WorkSource;
 import android.util.ArrayMap;
 import android.util.LocalLog;
@@ -53,7 +52,6 @@ import com.android.internal.util.AsyncChannel;
 import com.android.internal.util.Protocol;
 import com.android.internal.util.State;
 import com.android.internal.util.StateMachine;
-import com.android.internal.util.WakeupMessage;
 import com.android.server.wifi.scanner.BackgroundScanScheduler;
 import com.android.server.wifi.scanner.ChannelHelper;
 import com.android.server.wifi.scanner.ChannelHelper.ChannelCollection;
@@ -228,9 +226,8 @@ public class WifiScanningServiceImpl extends IWifiScanner.Stub {
     private static final int CMD_SCAN_PAUSED                         = BASE + 8;
     private static final int CMD_SCAN_RESTARTED                      = BASE + 9;
     private static final int CMD_SCAN_FAILED                         = BASE + 10;
-    private static final int CMD_SCAN_TIMEOUT                        = BASE + 11;
-    private static final int CMD_PNO_NETWORK_FOUND                   = BASE + 12;
-    private static final int CMD_PNO_SCAN_FAILED                     = BASE + 13;
+    private static final int CMD_PNO_NETWORK_FOUND                   = BASE + 11;
+    private static final int CMD_PNO_SCAN_FAILED                     = BASE + 12;
 
     private final Context mContext;
     private final Looper mLooper;
@@ -462,27 +459,8 @@ public class WifiScanningServiceImpl extends IWifiScanner.Stub {
         }
 
         class ScanningState extends State {
-            /**
-             * Duration to wait before timing out a scan.
-             *
-             * The expected behavior is that the hardware will return a failed scan if it does not
-             * complete, but timeout just in case it does not.
-             * It is possible that there may already be a scan in progress when the scan is
-             * scheduled, so make sure that there is time for two scans to complete.
-             */
-            private static final long SINGLE_SCAN_TIMEOUT_MS = 20000;
-            private WakeupMessage mTimeoutMessage = new WakeupMessage(mContext, getHandler(),
-                    "WifiScanner Single Scan Timeout", CMD_SCAN_TIMEOUT);
-
-            @Override
-            public void enter() {
-                mTimeoutMessage.schedule(
-                        SystemClock.elapsedRealtime() + SINGLE_SCAN_TIMEOUT_MS);
-            }
-
             @Override
             public void exit() {
-                mTimeoutMessage.cancel();
                 // if any scans are still active (never got results available then indicate failure)
                 sendOpFailedToAllAndClear(mActiveScans, WifiScanner.REASON_UNSPECIFIED,
                         "Scan was interrupted");
@@ -505,12 +483,6 @@ public class WifiScanningServiceImpl extends IWifiScanner.Stub {
                                 "Scan failed");
                         transitionTo(mIdleState);
                         return HANDLED;
-                    case CMD_SCAN_TIMEOUT:
-                        sendOpFailedToAllAndClear(mActiveScans, WifiScanner.REASON_UNSPECIFIED,
-                                "Timed out waiting for a scan result");
-                        loge("Timed out waiting for single scan result/failure");
-                        transitionTo(mIdleState);
-                        return HANDLED;
                     default:
                         return NOT_HANDLED;
                 }