You can't fsync(2) /dev/urandom...

...so don't even try. Doing so leads to this:

W/EntropyService( 1586): unable to load initial entropy (first boot?)
W/EntropyService( 1586): java.io.SyncFailedException: fsync failed: EINVAL (Invalid argument)
W/EntropyService( 1586): 	at java.io.FileDescriptor.sync(FileDescriptor.java:73)
W/EntropyService( 1586): 	at java.io.RandomAccessFile.write(RandomAccessFile.java:694)
W/EntropyService( 1586): 	at java.io.RandomAccessFile.write(RandomAccessFile.java:676)
W/EntropyService( 1586): 	at com.android.server.RandomBlock.toDataOut(RandomBlock.java:88)
W/EntropyService( 1586): 	at com.android.server.RandomBlock.toFile(RandomBlock.java:70)
W/EntropyService( 1586): 	at com.android.server.EntropyService.loadInitialEntropy(EntropyService.java:99)
W/EntropyService( 1586): 	at com.android.server.EntropyService.<init>(EntropyService.java:86)
W/EntropyService( 1586): 	at com.android.server.EntropyService.<init>(EntropyService.java:76)
W/EntropyService( 1586): 	at com.android.server.ServerThread.run(SystemServer.java:139)
W/EntropyService( 1586): Caused by: libcore.io.ErrnoException: fsync failed: EINVAL (Invalid argument)
W/EntropyService( 1586): 	at libcore.io.Posix.fsync(Native Method)
W/EntropyService( 1586): 	at libcore.io.BlockGuardOs.fsync(BlockGuardOs.java:39)
W/EntropyService( 1586): 	at java.io.FileDescriptor.sync(FileDescriptor.java:71)
W/EntropyService( 1586): 	... 8 more

Change-Id: I598a9456eccec0ca087f1568d47b6b8e531de8a8

2 files changed, 4 insertions, 4 deletions

diff --git a/services/java/com/android/server/EntropyService.java b/services/java/com/android/server/EntropyService.java
index 0f1fc7876a59..788a2f53bbdf 100644
--- a/services/java/com/android/server/EntropyService.java
+++ b/services/java/com/android/server/EntropyService.java
@@ -96,7 +96,7 @@ public class EntropyService extends Binder {
 
     private void loadInitialEntropy() {
         try {
-            RandomBlock.fromFile(entropyFile).toFile(randomDevice);
+            RandomBlock.fromFile(entropyFile).toFile(randomDevice, false);
         } catch (IOException e) {
             Slog.w(TAG, "unable to load initial entropy (first boot?)", e);
         }
@@ -104,7 +104,7 @@ public class EntropyService extends Binder {
 
     private void writeEntropy() {
         try {
-            RandomBlock.fromFile(randomDevice).toFile(entropyFile);
+            RandomBlock.fromFile(randomDevice).toFile(entropyFile, true);
         } catch (IOException e) {
             Slog.w(TAG, "unable to write entropy", e);
         }
diff --git a/services/java/com/android/server/RandomBlock.java b/services/java/com/android/server/RandomBlock.java
index cc22bd9b00cb..e5d73015cdfc 100644
--- a/services/java/com/android/server/RandomBlock.java
+++ b/services/java/com/android/server/RandomBlock.java
@@ -62,11 +62,11 @@ class RandomBlock {
         return retval;
     }
 
-    void toFile(String filename) throws IOException {
+    void toFile(String filename, boolean sync) throws IOException {
         if (DEBUG) Slog.v(TAG, "writing to file " + filename);
         RandomAccessFile out = null;
         try {
-            out = new RandomAccessFile(filename, "rws");
+            out = new RandomAccessFile(filename, sync ? "rws" : "rw");
             toDataOut(out);
             truncateIfPossible(out);
         } finally {