Make Tethering#dump asynchronous.

This is in preparation for removing mPublicSync.

Test: m
Test: adb shell dumpsys tethering
Test: atest TetheringTests TetheringIntegrationTests
Change-Id: Ib2c9d0bff23614f76c8e075d32cb03412d3d21f7

Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java

@@ -47,7 +47,6 @@ import android.net.netstats.provider.NetworkStatsProvider;
 import android.net.util.InterfaceParams;
 import android.net.util.SharedLog;
 import android.net.util.TetheringUtils.ForwardedStats;
-import android.os.ConditionVariable;
 import android.os.Handler;
 import android.system.ErrnoException;
 import android.text.TextUtils;
@@ -735,43 +734,35 @@ public class BpfCoordinator {
      * be allowed to be accessed on the handler thread.
      */
     public void dump(@NonNull IndentingPrintWriter pw) {
-        final ConditionVariable dumpDone = new ConditionVariable();
+        pw.println("mIsBpfEnabled: " + mIsBpfEnabled);
-        mHandler.post(() -> {
+        pw.println("Polling " + (mPollingStarted ? "started" : "not started"));
-            pw.println("mIsBpfEnabled: " + mIsBpfEnabled);
+        pw.println("Stats provider " + (mStatsProvider != null
-            pw.println("Polling " + (mPollingStarted ? "started" : "not started"));
+                ? "registered" : "not registered"));
-            pw.println("Stats provider " + (mStatsProvider != null
+        pw.println("Upstream quota: " + mInterfaceQuotas.toString());
-                    ? "registered" : "not registered"));
+        pw.println("Polling interval: " + getPollingInterval() + " ms");
-            pw.println("Upstream quota: " + mInterfaceQuotas.toString());
+        pw.println("Bpf shim: " + mBpfCoordinatorShim.toString());
-            pw.println("Polling interval: " + getPollingInterval() + " ms");
-            pw.println("Bpf shim: " + mBpfCoordinatorShim.toString());
 
-            pw.println("Forwarding stats:");
+        pw.println("Forwarding stats:");
-            pw.increaseIndent();
+        pw.increaseIndent();
-            if (mStats.size() == 0) {
+        if (mStats.size() == 0) {
-                pw.println("<empty>");
+            pw.println("<empty>");
-            } else {
+        } else {
-                dumpStats(pw);
+            dumpStats(pw);
-            }
-            pw.decreaseIndent();
-
-            pw.println("Forwarding rules:");
-            pw.increaseIndent();
-            dumpIpv6UpstreamRules(pw);
-            dumpIpv6ForwardingRules(pw);
-            dumpIpv4ForwardingRules(pw);
-            pw.decreaseIndent();
-
-            pw.println();
-            pw.println("Forwarding counters:");
-            pw.increaseIndent();
-            dumpCounters(pw);
-            pw.decreaseIndent();
-
-            dumpDone.open();
-        });
-        if (!dumpDone.block(DUMP_TIMEOUT_MS)) {
-            pw.println("... dump timed-out after " + DUMP_TIMEOUT_MS + "ms");
         }
+        pw.decreaseIndent();
+
+        pw.println("Forwarding rules:");
+        pw.increaseIndent();
+        dumpIpv6UpstreamRules(pw);
+        dumpIpv6ForwardingRules(pw);
+        dumpIpv4ForwardingRules(pw);
+        pw.decreaseIndent();
+
+        pw.println();
+        pw.println("Forwarding counters:");
+        pw.increaseIndent();
+        dumpCounters(pw);
+        pw.decreaseIndent();
     }
 
     private void dumpStats(@NonNull IndentingPrintWriter pw) {

Tethering/src/com/android/networkstack/tethering/EntitlementManager.java

@@ -41,7 +41,6 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.net.util.SharedLog;
 import android.os.Bundle;
-import android.os.ConditionVariable;
 import android.os.Handler;
 import android.os.Parcel;
 import android.os.PersistableBundle;
@@ -516,25 +515,18 @@ public class EntitlementManager {
      * @param pw {@link PrintWriter} is used to print formatted
      */
     public void dump(PrintWriter pw) {
-        final ConditionVariable mWaiting = new ConditionVariable();
+        pw.print("isCellularUpstreamPermitted: ");
-        mHandler.post(() -> {
+        pw.println(isCellularUpstreamPermitted());
-            pw.print("isCellularUpstreamPermitted: ");
+        for (int type = mCurrentDownstreams.nextSetBit(0); type >= 0;
-            pw.println(isCellularUpstreamPermitted());
+                type = mCurrentDownstreams.nextSetBit(type + 1)) {
-            for (int type = mCurrentDownstreams.nextSetBit(0); type >= 0;
+            pw.print("Type: ");
-                    type = mCurrentDownstreams.nextSetBit(type + 1)) {
+            pw.print(typeString(type));
-                pw.print("Type: ");
+            if (mCurrentEntitlementResults.indexOfKey(type) > -1) {
-                pw.print(typeString(type));
+                pw.print(", Value: ");
-                if (mCurrentEntitlementResults.indexOfKey(type) > -1) {
+                pw.println(errorString(mCurrentEntitlementResults.get(type)));
-                    pw.print(", Value: ");
+            } else {
-                    pw.println(errorString(mCurrentEntitlementResults.get(type)));
+                pw.println(", Value: empty");
-                } else {
-                    pw.println(", Value: empty");
-                }
             }
-            mWaiting.open();
-        });
-        if (!mWaiting.block(DUMP_TIMEOUT)) {
-            pw.println("... dump timed out after " + DUMP_TIMEOUT + "ms");
         }
         pw.print("Exempted: [");
         for (int type = mExemptedDownstreams.nextSetBit(0); type >= 0;

Tethering/src/com/android/networkstack/tethering/Tethering.java

@@ -147,8 +147,11 @@ import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  *
@@ -166,6 +169,9 @@ public class Tethering {
     };
     private static final SparseArray<String> sMagicDecoderRing =
             MessageUtils.findMessageNames(sMessageClasses);
+
+    private static final int DUMP_TIMEOUT_MS = 10_000;
+
     // Keep in sync with NETID_UNSET in system/netd/include/netid_client.h
     private static final int NETID_UNSET = 0;
 
@@ -2278,15 +2284,10 @@ public class Tethering {
         pw.decreaseIndent();
     }
 
-    void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter writer, @Nullable String[] args) {
+    void doDump(@NonNull FileDescriptor fd, @NonNull PrintWriter writer, @Nullable String[] args) {
         // Binder.java closes the resource for us.
-        @SuppressWarnings("resource")
+        @SuppressWarnings("resource") final IndentingPrintWriter pw = new IndentingPrintWriter(
-        final IndentingPrintWriter pw = new IndentingPrintWriter(writer, "  ");
+                writer, "  ");
-        if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.DUMP)
-                != PERMISSION_GRANTED) {
-            pw.println("Permission Denial: can't dump.");
-            return;
-        }
 
         if (argsContain(args, "bpf")) {
             dumpBpf(pw);
@@ -2363,6 +2364,40 @@ public class Tethering {
         pw.decreaseIndent();
     }
 
+    void dump(@NonNull FileDescriptor fd, @NonNull PrintWriter writer, @Nullable String[] args) {
+        if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.DUMP)
+                != PERMISSION_GRANTED) {
+            writer.println("Permission Denial: can't dump.");
+            return;
+        }
+
+        final CountDownLatch latch = new CountDownLatch(1);
+
+        // Don't crash the system if something in doDump throws an exception, but try to propagate
+        // the exception to the caller.
+        AtomicReference<RuntimeException> exceptionRef = new AtomicReference<>();
+        mHandler.post(() -> {
+            try {
+                doDump(fd, writer, args);
+            } catch (RuntimeException e) {
+                exceptionRef.set(e);
+            }
+            latch.countDown();
+        });
+
+        try {
+            if (!latch.await(DUMP_TIMEOUT_MS, TimeUnit.MILLISECONDS)) {
+                writer.println("Dump timeout after " + DUMP_TIMEOUT_MS + "ms");
+                return;
+            }
+        } catch (InterruptedException e) {
+            exceptionRef.compareAndSet(null, new IllegalStateException("Dump interrupted", e));
+        }
+
+        final RuntimeException e = exceptionRef.get();
+        if (e != null) throw e;
+    }
+
     private static boolean argsContain(String[] args, String target) {
         for (String arg : args) {
             if (target.equals(arg)) return true;