Handle the race condition when calling uncrypt services.

We call uncrypt services to setup / clear bootloader control block (BCB)
for scheduling tasks under recovery (applying OTAs, performing FDR).
However, we cannot start multiple requests simultaneously. Because they
all use the same socket (/dev/socket/uncrypt) for communication and init
deletes the socket on service exits.

This CL fixes the issue by a) adding synchronized blocks for the service
requests; b) checking the availability of the socket before initiating a
new one.

Note that adding synchronized blocks to RecoverySystem doesn't help,
because the calls could be made from different processes (e.g. priv-app,
system_server).

Bug: 31526152
Test: FDR works while a priv-app keeps calling clear BCB.

Change-Id: I95308989e849a9c98a9503ac509f2bc51ed3de19

1 files changed, 23 insertions, 18 deletions

diff --git a/core/java/android/os/RecoverySystem.java b/core/java/android/os/RecoverySystem.java
index 028e30ab93f0..df7df64de813 100644
--- a/core/java/android/os/RecoverySystem.java
+++ b/core/java/android/os/RecoverySystem.java
@@ -663,28 +663,22 @@ public class RecoverySystem {
      * @throws IOException if something goes wrong.
      */
     private static void bootCommand(Context context, String... args) throws IOException {
-        synchronized (sRequestLock) {
-            LOG_FILE.delete();
+        LOG_FILE.delete();
 
-            StringBuilder command = new StringBuilder();
-            for (String arg : args) {
-                if (!TextUtils.isEmpty(arg)) {
-                    command.append(arg);
-                    command.append("\n");
-                }
+        StringBuilder command = new StringBuilder();
+        for (String arg : args) {
+            if (!TextUtils.isEmpty(arg)) {
+                command.append(arg);
+                command.append("\n");
             }
+        }
 
-            // Write the command into BCB (bootloader control block).
-            RecoverySystem rs = (RecoverySystem) context.getSystemService(
-                    Context.RECOVERY_SERVICE);
-            rs.setupBcb(command.toString());
-
-            // Having set up the BCB, go ahead and reboot.
-            PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
-            pm.reboot(PowerManager.REBOOT_RECOVERY);
+        // Write the command into BCB (bootloader control block) and boot from
+        // there. Will not return unless failed.
+        RecoverySystem rs = (RecoverySystem) context.getSystemService(Context.RECOVERY_SERVICE);
+        rs.rebootRecoveryWithCommand(command.toString());
 
-            throw new IOException("Reboot failed (no permissions?)");
-        }
+        throw new IOException("Reboot failed (no permissions?)");
     }
 
     // Read last_install; then report time (in seconds) and I/O (in MiB) for
@@ -879,6 +873,17 @@ public class RecoverySystem {
     }
 
     /**
+     * Talks to RecoverySystemService via Binder to set up the BCB command and
+     * reboot into recovery accordingly.
+     */
+    private void rebootRecoveryWithCommand(String command) {
+        try {
+            mService.rebootRecoveryWithCommand(command);
+        } catch (RemoteException ignored) {
+        }
+    }
+
+    /**
      * Internally, recovery treats each line of the command file as a separate
      * argv, so we only need to protect against newlines and nulls.
      */