From c74389c5fc9689d1db53e690a5b03b29bf38f416 Mon Sep 17 00:00:00 2001
From: Chalard Jean <jchalard@google.com>
Date: Fri, 6 Nov 2020 15:52:15 +0900
Subject: [PATCH] Remove useless code

The semantics of this block are such that restart will
only be false if all components of mArguments are null.
mArguments is a final array initialized in the
constructor of LegacyVpnRunner. The components of the
array are never overwritten (though the components of
those components are), and at least one of these
components will always be non-null (unless somebody
calls startLegacyVpnPrivileged with a non-existing
type, but that never happens).

For safety, this patch also adds a check so that
the code will crash early with a clear message if this
ever happens.

Test: FrameworksNetTests NetworkStackTests
Change-Id: I1f13aa08c6f1870c9610185b603af76f97c22bab
---
 .../java/com/android/server/connectivity/Vpn.java    | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/services/core/java/com/android/server/connectivity/Vpn.java b/services/core/java/com/android/server/connectivity/Vpn.java
index 9e43b54817390..8b56a2b64db29 100644
--- a/services/core/java/com/android/server/connectivity/Vpn.java
+++ b/services/core/java/com/android/server/connectivity/Vpn.java
@@ -25,6 +25,7 @@ import static android.net.NetworkCapabilities.NET_CAPABILITY_NOT_SUSPENDED;
 import static android.net.RouteInfo.RTN_THROW;
 import static android.net.RouteInfo.RTN_UNREACHABLE;
 
+import static com.android.internal.util.Preconditions.checkArgument;
 import static com.android.internal.util.Preconditions.checkNotNull;
 
 import android.Manifest;
@@ -2759,6 +2760,8 @@ public class Vpn {
 
         LegacyVpnRunner(VpnConfig config, String[] racoon, String[] mtpd, VpnProfile profile) {
             super(TAG);
+            checkArgument(racoon != null || mtpd != null, "Arguments to racoon and mtpd "
+                    + "must not both be null");
             mConfig = config;
             mDaemons = new String[] {"racoon", "mtpd"};
             // TODO: clear arguments from memory once launched
@@ -2915,15 +2918,6 @@ public class Vpn {
                 }
                 new File("/data/misc/vpn/abort").delete();
 
-                // Check if we need to restart any of the daemons.
-                boolean restart = false;
-                for (String[] arguments : mArguments) {
-                    restart = restart || (arguments != null);
-                }
-                if (!restart) {
-                    agentDisconnect();
-                    return;
-                }
                 updateState(DetailedState.CONNECTING, "execute");
 
                 // Start the daemon with arguments.