Allow incoming SMS until internal storage is almost full.

Fix for bug 2382830: new incoming SMS should not be rejected when
running low on internal phone storage.

Testing revealed that the /data partition should have at least 256 KiB
available in order to prevent random app crashes (including system apps)
due to SQLite transaction failures. With 256 KiB free, the device should
safely boot without storage full errors. This takes into account the
36-40 KiB that the YAFFS2 filesystem reports as available even after
the partition has been completely filled. I've set the default full
threshold to 1 MiB to provide a generous safety margin.

For this bug, I changed the DeviceStorageMonitorService demon to send
two new hidden notifications for device storage "full" and "not full",
when the free space falls below the full threshold (default 1 MiB,
but configurable as a system setting), in addition to the existing
storage low/okay notifications sent when the storage crosses the threshold
of 90% full (also configurable).

The SMS code was changed to use these new notifications so that it can
accept messages until the data partition has been filled to the maximum
safe capacity rather than stopping when it hits 90% full. There should
be no negative impact on battery life because the additional check in
the storage polling service should be offset by an optimization to cache
the free threshold values which were previously being computed every time
through the loop.

While testing this change, I discovered that SMSDispatcher was being
instantiated twice, the first time in GSMPhone/CDMAPhone, and the second
time in SimSmsInterfaceManager / RuimSmsInterfaceManager. Changed the code
to pass the original SMSDispatcher to the Sim/RuimSmsInterfaceManager
constructor.

Change-Id: Ie0c6d05294778ab6ee42e0fa01313af96d824c77

1 files changed, 58 insertions, 4 deletions

diff --git a/services/java/com/android/server/DeviceStorageMonitorService.java b/services/java/com/android/server/DeviceStorageMonitorService.java
index 4a0df59..0b1a4a3 100644
--- a/services/java/com/android/server/DeviceStorageMonitorService.java
+++ b/services/java/com/android/server/DeviceStorageMonitorService.java
@@ -69,10 +69,12 @@ class DeviceStorageMonitorService extends Binder {
     private static final int DEFAULT_FREE_STORAGE_LOG_INTERVAL_IN_MINUTES = 12*60; //in minutes
     private static final long DEFAULT_DISK_FREE_CHANGE_REPORTING_THRESHOLD = 2 * 1024 * 1024; // 2MB
     private static final long DEFAULT_CHECK_INTERVAL = MONITOR_INTERVAL*60*1000;
+    private static final int DEFAULT_FULL_THRESHOLD_BYTES = 1024*1024; // 1MB
     private long mFreeMem;  // on /data
     private long mLastReportedFreeMem;
     private long mLastReportedFreeMemTime;
     private boolean mLowMemFlag=false;
+    private boolean mMemFullFlag=false;
     private Context mContext;
     private ContentResolver mContentResolver;
     private long mTotalMemory;  // on /data
@@ -87,9 +89,13 @@ class DeviceStorageMonitorService extends Binder {
     private boolean mClearingCache;
     private Intent mStorageLowIntent;
     private Intent mStorageOkIntent;
+    private Intent mStorageFullIntent;
+    private Intent mStorageNotFullIntent;
     private CachePackageDataObserver mClearCacheObserver;
     private static final int _TRUE = 1;
     private static final int _FALSE = 0;
+    private long mMemLowThreshold;
+    private int mMemFullThreshold;
 
     /**
      * This string is used for ServiceManager access to this class.
@@ -103,7 +109,7 @@ class DeviceStorageMonitorService extends Binder {
     Handler mHandler = new Handler() {
         @Override
         public void handleMessage(Message msg) {
-            //dont handle an invalid message
+            //don't handle an invalid message
             if (msg.what != DEVICE_MEMORY_WHAT) {
                 Slog.e(TAG, "Will not process invalid message");
                 return;
@@ -184,7 +190,7 @@ class DeviceStorageMonitorService extends Binder {
         try {
             if (localLOGV) Slog.i(TAG, "Clearing cache");
             IPackageManager.Stub.asInterface(ServiceManager.getService("package")).
-                    freeStorageAndNotify(getMemThreshold(), mClearCacheObserver);
+                    freeStorageAndNotify(mMemLowThreshold, mClearCacheObserver);
         } catch (RemoteException e) {
             Slog.w(TAG, "Failed to get handle for PackageManger Exception: "+e);
             mClearingCache = false;
@@ -209,8 +215,7 @@ class DeviceStorageMonitorService extends Binder {
             if (localLOGV)  Slog.v(TAG, "freeMemory="+mFreeMem);
 
             //post intent to NotificationManager to display icon if necessary
-            long memThreshold = getMemThreshold();
-            if (mFreeMem < memThreshold) {
+            if (mFreeMem < mMemLowThreshold) {
                 if (!mLowMemFlag) {
                     if (checkCache) {
                         // See if clearing cache helps
@@ -235,6 +240,17 @@ class DeviceStorageMonitorService extends Binder {
                     mLowMemFlag = false;
                 }
             }
+            if (mFreeMem < mMemFullThreshold) {
+                if (!mMemFullFlag) {
+                    sendFullNotification();
+                    mMemFullFlag = true;
+                }
+            } else {
+                if (mMemFullFlag) {
+                    cancelFullNotification();
+                    mMemFullFlag = false;
+                }
+            }
         }
         if(localLOGV) Slog.i(TAG, "Posting Message again");
         //keep posting messages to itself periodically
@@ -264,6 +280,20 @@ class DeviceStorageMonitorService extends Binder {
         return mTotalMemory*value;
     }
 
+    /*
+     * just query settings to retrieve the memory full threshold.
+     * Preferred this over using a ContentObserver since Settings.Secure caches the value
+     * any way
+     */
+    private int getMemFullThreshold() {
+        int value = Settings.Secure.getInt(
+                              mContentResolver,
+                              Settings.Secure.SYS_STORAGE_FULL_THRESHOLD_BYTES,
+                              DEFAULT_FULL_THRESHOLD_BYTES);
+        if(localLOGV) Slog.v(TAG, "Full Threshold Bytes="+value);
+        return value;
+    }
+
     /**
     * Constructor to run service. initializes the disk space threshold value
     * and posts an empty message to kickstart the process.
@@ -283,6 +313,13 @@ class DeviceStorageMonitorService extends Binder {
         mStorageLowIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
         mStorageOkIntent = new Intent(Intent.ACTION_DEVICE_STORAGE_OK);
         mStorageOkIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+        mStorageFullIntent = new Intent(Intent.ACTION_DEVICE_STORAGE_FULL);
+        mStorageFullIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+        mStorageNotFullIntent = new Intent(Intent.ACTION_DEVICE_STORAGE_NOT_FULL);
+        mStorageNotFullIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+        // cache storage thresholds
+        mMemLowThreshold = getMemThreshold();
+        mMemFullThreshold = getMemFullThreshold();
         checkMemory(true);
     }
 
@@ -332,6 +369,23 @@ class DeviceStorageMonitorService extends Binder {
         mContext.sendBroadcast(mStorageOkIntent);
     }
 
+    /**
+     * Send a notification when storage is full.
+     */
+    private final void sendFullNotification() {
+        if(localLOGV) Slog.i(TAG, "Sending memory full notification");
+        mContext.sendStickyBroadcast(mStorageFullIntent);
+    }
+
+    /**
+     * Cancels memory full notification and sends "not full" intent.
+     */
+    private final void cancelFullNotification() {
+        if(localLOGV) Slog.i(TAG, "Canceling memory full notification");
+        mContext.removeStickyBroadcast(mStorageFullIntent);
+        mContext.sendBroadcast(mStorageNotFullIntent);
+    }
+
     public void updateMemory() {
         int callingUid = getCallingUid();
         if(callingUid != Process.SYSTEM_UID) {