Cleaner controls between Vpn and init services.

Change-Id: I35edf054f4a1190f7fb7b4c48ee832e899c9528b

Author: jsharkey

core/java/android/os/SystemService.java

@@ -16,15 +16,53 @@
 
 package android.os;
 
-/** @hide */
-public class SystemService
-{
-        /** Request that the init daemon start a named service. */
+import com.google.android.collect.Maps;
+
+import java.util.HashMap;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * Controls and utilities for low-level {@code init} services.
+ *
+ * @hide
+ */
+public class SystemService {
+
+    private static HashMap<String, State> sStates = Maps.newHashMap();
+
+    /**
+     * State of a known {@code init} service.
+     */
+    public enum State {
+        RUNNING("running"),
+        STOPPING("stopping"),
+        STOPPED("stopped"),
+        RESTARTING("restarting");
+
+        State(String state) {
+            sStates.put(state, this);
+        }
+    }
+
+    private static Object sPropertyLock = new Object();
+
+    static {
+        SystemProperties.addChangeCallback(new Runnable() {
+            @Override
+            public void run() {
+                synchronized (sPropertyLock) {
+                    sPropertyLock.notifyAll();
+                }
+            }
+        });
+    }
+
+    /** Request that the init daemon start a named service. */
     public static void start(String name) {
         SystemProperties.set("ctl.start", name);
     }
-    
-        /** Request that the init daemon stop a named service. */
+
+    /** Request that the init daemon stop a named service. */
     public static void stop(String name) {
         SystemProperties.set("ctl.stop", name);
     }
@@ -33,4 +71,77 @@ public static void stop(String name) {
     public static void restart(String name) {
         SystemProperties.set("ctl.restart", name);
     }
+
+    /**
+     * Return current state of given service.
+     */
+    public static State getState(String service) {
+        final String rawState = SystemProperties.get("init.svc." + service);
+        final State state = sStates.get(rawState);
+        if (state != null) {
+            return state;
+        } else {
+            throw new IllegalStateException("Service " + service + " in unknown state " + rawState);
+        }
+    }
+
+    /**
+     * Check if given service is {@link State#STOPPED}.
+     */
+    public static boolean isStopped(String service) {
+        return State.STOPPED.equals(getState(service));
+    }
+
+    /**
+     * Check if given service is {@link State#RUNNING}.
+     */
+    public static boolean isRunning(String service) {
+        return State.RUNNING.equals(getState(service));
+    }
+
+    /**
+     * Wait until given service has entered specific state.
+     */
+    public static void waitForState(String service, State state, long timeoutMillis)
+            throws TimeoutException {
+        final long endMillis = SystemClock.elapsedRealtime() + timeoutMillis;
+        while (true) {
+            synchronized (sPropertyLock) {
+                final State currentState = getState(service);
+                if (state.equals(currentState)) {
+                    return;
+                }
+
+                if (SystemClock.elapsedRealtime() >= endMillis) {
+                    throw new TimeoutException("Service " + service + " currently " + currentState
+                            + "; waited " + timeoutMillis + "ms for " + state);
+                }
+
+                try {
+                    sPropertyLock.wait(timeoutMillis);
+                } catch (InterruptedException e) {
+                }
+            }
+        }
+    }
+
+    /**
+     * Wait until any of given services enters {@link State#STOPPED}.
+     */
+    public static void waitForAnyStopped(String... services)  {
+        while (true) {
+            synchronized (sPropertyLock) {
+                for (String service : services) {
+                    if (State.STOPPED.equals(getState(service))) {
+                        return;
+                    }
+                }
+
+                try {
+                    sPropertyLock.wait();
+                } catch (InterruptedException e) {
+                }
+            }
+        }
+    }
 }

services/java/com/android/server/connectivity/Vpn.java

@@ -25,7 +25,6 @@
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
-import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.drawable.Drawable;
@@ -39,7 +38,7 @@
 import android.os.ParcelFileDescriptor;
 import android.os.Process;
 import android.os.SystemClock;
-import android.os.SystemProperties;
+import android.os.SystemService;
 import android.util.Log;
 
 import com.android.internal.R;
@@ -485,8 +484,7 @@ private void execute() {
 
                 // Wait for the daemons to stop.
                 for (String daemon : mDaemons) {
-                    String key = "init.svc." + daemon;
-                    while (!"stopped".equals(SystemProperties.get(key, "stopped"))) {
+                    while (!SystemService.isStopped(daemon)) {
                         checkpoint(true);
                     }
                 }
@@ -519,11 +517,10 @@ private void execute() {
 
                     // Start the daemon.
                     String daemon = mDaemons[i];
-                    SystemProperties.set("ctl.start", daemon);
+                    SystemService.start(daemon);
 
                     // Wait for the daemon to start.
-                    String key = "init.svc." + daemon;
-                    while (!"running".equals(SystemProperties.get(key))) {
+                    while (!SystemService.isRunning(daemon)) {
                         checkpoint(true);
                     }
 
@@ -579,8 +576,7 @@ private void execute() {
                     // Check if a running daemon is dead.
                     for (int i = 0; i < mDaemons.length; ++i) {
                         String daemon = mDaemons[i];
-                        if (mArguments[i] != null && !"running".equals(
-                                SystemProperties.get("init.svc." + daemon))) {
+                        if (mArguments[i] != null && !SystemService.isRunning(daemon)) {
                             throw new IllegalStateException(daemon + " is dead");
                         }
                     }
@@ -647,7 +643,7 @@ private void execute() {
                 // Kill the daemons if they fail to stop.
                 if (mInfo.state == LegacyVpnInfo.STATE_INITIALIZING) {
                     for (String daemon : mDaemons) {
-                        SystemProperties.set("ctl.stop", daemon);
+                        SystemService.stop(daemon);
                     }
                 }