Merge "Retry property set failures" into main (518396a3) · Commits · e / os / android_frameworks_base

core/java/android/app/PropertyInvalidatedCache.java

+2 −45

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ import android.util.ArraySet;
		import android.util.Log;
		import android.util.SparseArray;
		import android.util.SparseBooleanArray;
		import android.util.SystemPropertySetter;

		import com.android.internal.annotations.GuardedBy;
		import com.android.internal.annotations.VisibleForTesting;
		@@ -156,21 +157,6 @@ public class PropertyInvalidatedCache<Query, Result> {
		*/
		public static final String MODULE_TELEPHONY = "telephony";

		/**
		* Constants that affect retries when the process is unable to write the property.
		* The first constant is the number of times the process will attempt to set the
		* property. The second constant is the delay between attempts.
		*/

		/**
		* Wait 200ms between retry attempts and the retry limit is 5. That gives a total possible
		* delay of 1s, which should be less than ANR timeouts. The goal is to have the system crash
		* because the property could not be set (which is a condition that is easily recognized) and
		* not crash because of an ANR (which can be confusing to debug).
		*/
		private static final int PROPERTY_FAILURE_RETRY_DELAY_MILLIS = 200;
		private static final int PROPERTY_FAILURE_RETRY_LIMIT = 5;

		/**
		* Construct a system property that matches the rules described above. The module is
		* one of the permitted values above. The API is a string that is a legal Java simple
		@@ -958,37 +944,8 @@ public class PropertyInvalidatedCache<Query, Result> {
		*/
		@Override
		void setNonceInternal(long value) {
		// Failing to set the nonce is a fatal error. Failures setting a system property have
		// been reported; given that the failure is probably transient, this function includes
		// a retry.
		final String str = Long.toString(value);
		RuntimeException failure = null;
		for (int attempt = 0; attempt < PROPERTY_FAILURE_RETRY_LIMIT; attempt++) {
		try {
		SystemProperties.set(mName, str);
		if (attempt > 0) {
		// This log is not guarded. Based on known bug reports, it should
		// occur once a week or less. The purpose of the log message is to
		// identify the retries as a source of delay that might be otherwise
		// be attributed to the cache itself.
		Log.w(TAG, "Nonce set after " + attempt + " tries");
		}
		return;
		} catch (RuntimeException e) {
		if (failure == null) {
		failure = e;
		}
		try {
		Thread.sleep(PROPERTY_FAILURE_RETRY_DELAY_MILLIS);
		} catch (InterruptedException x) {
		// Ignore this exception. The desired delay is only approximate and
		// there is no issue if the sleep sometimes terminates early.
		}
		}
		}
		// This point is reached only if SystemProperties.set() fails at least once.
		// Rethrow the first exception that was received.
		throw failure;
		SystemPropertySetter.setWithRetry(mName, str);
		}
		}

core/java/android/util/SystemPropertySetter.java

0 → 100644

+103 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2025 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		package android.util;

		import android.annotation.NonNull;
		import android.annotation.Nullable;
		import android.os.SystemProperties;

		/**
		* This class provides a single, static function to set a system property. The function retries on
		* error. System properties should be reliable but there have been reports of failures in the set()
		* command on lower-end devices. Clients may want to use this method instead of calling
		* {@link SystemProperties.set} directly.
		* @hide
		*/
		public class SystemPropertySetter {

		/**
		* The default retryDelayMs for {@link #setWithRetry}. This value has been found to give
		* reasonable behavior in the field.
		*/
		public static final int PROPERTY_FAILURE_RETRY_DELAY_MILLIS = 200;

		/**
		* The default retryLimit for {@link #setWithRetry}. This value has been found to give
		* reasonable behavior in the field.
		*/
		public static final int PROPERTY_FAILURE_RETRY_LIMIT = 5;

		/**
		* Set the value for the given {@code key} to {@code val}. This method retries using the
		* standard parameters, above, if the native method throws a RuntimeException.
		*
		* @param key The name of the property to be set.
		* @param val The new string value of the property.
		* @throws IllegalArgumentException for non read-only properties if the {@code val} exceeds
		* 91 characters.
		* @throws RuntimeException if the property cannot be set, for example, if it was blocked by
		* SELinux. libc will log the underlying reason.
		*/
		public static void setWithRetry(@NonNull String key, @Nullable String val) {
		setWithRetry(key, val,PROPERTY_FAILURE_RETRY_DELAY_MILLIS, PROPERTY_FAILURE_RETRY_LIMIT);
		}

		/**
		* Set the value for the given {@code key} to {@code val}. This method retries if the native
		* method throws a RuntimeException. If the {@code maxRetry} count is exceeded, the method
		* throws the first RuntimeException that was seen.
		*
		* @param key The name of the property to be set.
		* @param val The new string value of the property.
		* @param maxRetry The maximum number of times; must be non-negative.
		* @param retryDelayMs The number of milliseconds to wait between retries; must be positive.
		* @throws IllegalArgumentException for non read-only properties if the {@code val} exceeds
		* 91 characters, or if the retry parameters are invalid.
		* @throws RuntimeException if the property cannot be set, for example, if it was blocked by
		* SELinux. libc will log the underlying reason.
		*/
		public static void setWithRetry(@NonNull String key, @Nullable String val, int maxRetry,
		long retryDelayMs) {
		if (maxRetry < 0) {
		throw new IllegalArgumentException("invalid retry count: " + maxRetry);
		}
		if (retryDelayMs <= 0) {
		throw new IllegalArgumentException("invalid retry delay: " + retryDelayMs);
		}

		RuntimeException failure = null;
		for (int attempt = 0; attempt < maxRetry; attempt++) {
		try {
		SystemProperties.set(key, val);
		return;
		} catch (RuntimeException e) {
		if (failure == null) {
		failure = e;
		}
		try {
		Thread.sleep(retryDelayMs);
		} catch (InterruptedException x) {
		// Ignore this exception. The desired delay is only approximate and
		// there is no issue if the sleep sometimes terminates early.
		}
		}
		}
		// This point is reached only if SystemProperties.set() fails at least once.
		// Rethrow the first exception that was received.
		throw failure;
		}
		}

services/core/java/com/android/server/audio/AudioService.java

+2 −1

Original line number	Diff line number	Diff line
		@@ -242,6 +242,7 @@ import android.util.PrintWriterPrinter;
		import android.util.Slog;
		import android.util.SparseArray;
		import android.util.SparseIntArray;
		import android.util.SystemPropertySetter;
		import android.view.Display;
		import android.view.KeyEvent;
		import android.view.accessibility.AccessibilityManager;
		@@ -11032,7 +11033,7 @@ public class AudioService extends IAudioService.Stub
		@GuardedBy("mLock")
		private void updateLocked() {
		String n = Long.toString(mToken++);
		SystemProperties.set(PermissionManager.CACHE_KEY_PACKAGE_INFO_NOTIFY, n);
		SystemPropertySetter.setWithRetry(PermissionManager.CACHE_KEY_PACKAGE_INFO_NOTIFY, n);
		}

		private void trigger() {