From 75aeb6849f3b16478c9947849d5ceeaf3f3e6383 Mon Sep 17 00:00:00 2001
From: Felipe Leme <felipeal@google.com>
Date: Tue, 21 Jan 2020 14:22:14 -0800
Subject: [PATCH] Improved 'am switch' to handle errors.

Bug: 146207078
Test: adb shell am switch-user 42 ; echo $?

Change-Id: I005c76652be1fd0908f5c2b40e2513362b5ce5ac
---
 .../server/am/ActivityManagerShellCommand.java | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index d7ad1c2524014..a82fbf0804704 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -91,7 +91,6 @@ import android.view.Display;
 import com.android.internal.compat.CompatibilityChangeConfig;
 import com.android.internal.util.HexDump;
 import com.android.internal.util.MemInfoReader;
-import com.android.internal.util.Preconditions;
 import com.android.server.compat.PlatformCompat;
 
 import java.io.BufferedReader;
@@ -1734,7 +1733,7 @@ final class ActivityManagerShellCommand extends ShellCommand {
         return 0;
     }
 
-    private void switchUserAndWaitForComplete(int userId) throws RemoteException {
+    private boolean switchUserAndWaitForComplete(int userId) throws RemoteException {
         // Register switch observer.
         final CountDownLatch switchLatch = new CountDownLatch(1);
         mInterface.registerUserSwitchObserver(
@@ -1748,7 +1747,7 @@ final class ActivityManagerShellCommand extends ShellCommand {
                 }, ActivityManagerShellCommand.class.getName());
 
         // Switch.
-        mInterface.switchUser(userId);
+        boolean switched = mInterface.switchUser(userId);
 
         // Wait.
         try {
@@ -1756,6 +1755,7 @@ final class ActivityManagerShellCommand extends ShellCommand {
         } catch (InterruptedException e) {
             getErrPrintWriter().println("Thread interrupted unexpectedly.");
         }
+        return switched;
     }
 
     int runSwitchUser(PrintWriter pw) throws RemoteException {
@@ -1777,12 +1777,18 @@ final class ActivityManagerShellCommand extends ShellCommand {
         }
 
         int userId = Integer.parseInt(getNextArgRequired());
+        boolean switched;
         if (wait) {
-            switchUserAndWaitForComplete(userId);
+            switched = switchUserAndWaitForComplete(userId);
         } else {
-            mInterface.switchUser(userId);
+            switched = mInterface.switchUser(userId);
+        }
+        if (switched) {
+            return 0;
+        } else {
+            pw.printf("Failed to switch to user %d\n", userId);
+            return 1;
         }
-        return 0;
     }
 
     int runGetCurrentUser(PrintWriter pw) throws RemoteException {