PackageParser support for flagging manifest entries (1d71aa6f) · Commits · e / os / android_frameworks_base

Android.bp

+1 −0

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		@@ -425,6 +425,7 @@ java_defaults {
		"sounddose-aidl-java",
		"modules-utils-expresslog",
		"perfetto_trace_javastream_protos_jarjar",
		"libaconfig_java_proto_nano",
		],
		}

core/java/com/android/internal/pm/pkg/component/AconfigFlags.java

0 → 100644

+244 −0

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		/*
		* Copyright (C) 2024 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 com.android.internal.pm.pkg.component;

		import static com.android.internal.pm.pkg.parsing.ParsingUtils.ANDROID_RES_NAMESPACE;

		import android.aconfig.nano.Aconfig;
		import android.aconfig.nano.Aconfig.parsed_flag;
		import android.aconfig.nano.Aconfig.parsed_flags;
		import android.annotation.NonNull;
		import android.annotation.Nullable;
		import android.content.res.Flags;
		import android.content.res.XmlResourceParser;
		import android.os.Environment;
		import android.os.Process;
		import android.util.ArrayMap;
		import android.util.Slog;
		import android.util.Xml;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.modules.utils.TypedXmlPullParser;

		import org.xmlpull.v1.XmlPullParser;
		import org.xmlpull.v1.XmlPullParserException;

		import java.io.File;
		import java.io.FileInputStream;
		import java.io.IOException;
		import java.util.List;
		import java.util.Map;

		/**
		* A class that manages a cache of all device feature flags and their default + override values.
		* This class performs a very similar job to the one in {@code SettingsProvider}, with an important
		* difference: this is a part of system server and is available for the server startup. Package
		* parsing happens at the startup when {@code SettingsProvider} isn't available yet, so we need an
		* own copy of the code here.
		* @hide
		*/
		public class AconfigFlags {
		private static final String LOG_TAG = "AconfigFlags";

		private static final List<String> sTextProtoFilesOnDevice = List.of(
		"/system/etc/aconfig_flags.pb",
		"/system_ext/etc/aconfig_flags.pb",
		"/product/etc/aconfig_flags.pb",
		"/vendor/etc/aconfig_flags.pb");

		private final ArrayMap<String, Boolean> mFlagValues = new ArrayMap<>();

		public AconfigFlags() {
		if (!Flags.manifestFlagging()) {
		Slog.v(LOG_TAG, "Feature disabled, skipped all loading");
		return;
		}
		for (String fileName : sTextProtoFilesOnDevice) {
		try (var inputStream = new FileInputStream(fileName)) {
		loadAconfigDefaultValues(inputStream.readAllBytes());
		} catch (IOException e) {
		Slog.e(LOG_TAG, "Failed to read Aconfig values from " + fileName, e);
		}
		}
		if (Process.myUid() == Process.SYSTEM_UID) {
		// Server overrides are only accessible to the system, no need to even try loading them
		// in user processes.
		loadServerOverrides();
		}
		}

		private void loadServerOverrides() {
		// Reading the proto files is enough for READ_ONLY flags but if it's a READ_WRITE flag
		// (which you can check with `flag.getPermission() == flag_permission.READ_WRITE`) then we
		// also need to check if there is a value pushed from the server in the file
		// `/data/system/users/0/settings_config.xml`. It will be in a <setting> node under the
		// root <settings> node with "name" attribute == "flag_namespace/flag_package.flag_name".
		// The "value" attribute will be true or false.
		//
		// The "name" attribute could also be "<namespace>/flag_namespace?flag_package.flag_name"
		// (prefixed with "staged/" or "device_config_overrides/" and a different separator between
		// namespace and name). This happens when a flag value is overridden either with a pushed
		// one from the server, or from the local command.
		// When the device reboots during package parsing, the staged value will still be there and
		// only later it will become a regular/non-staged value after SettingsProvider is
		// initialized.
		//
		// In all cases, when there is more than one value, the priority is:
		// device_config_overrides > staged > default
		//

		final var settingsFile = new File(Environment.getUserSystemDirectory(0),
		"settings_config.xml");
		try (var inputStream = new FileInputStream(settingsFile)) {
		TypedXmlPullParser parser = Xml.resolvePullParser(inputStream);
		if (parser.next() != XmlPullParser.END_TAG && "settings".equals(parser.getName())) {
		final var flagPriority = new ArrayMap<String, Integer>();
		final int outerDepth = parser.getDepth();
		int type;
		while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
		&& (type != XmlPullParser.END_TAG \|\| parser.getDepth() > outerDepth)) {
		if (type == XmlPullParser.END_TAG \|\| type == XmlPullParser.TEXT) {
		continue;
		}
		if (!"setting".equals(parser.getName())) {
		continue;
		}
		String name = parser.getAttributeValue(null, "name");
		final String value = parser.getAttributeValue(null, "value");
		if (name == null \|\| value == null) {
		continue;
		}
		// A non-boolean setting is definitely not an Aconfig flag value.
		if (!"false".equalsIgnoreCase(value) && !"true".equalsIgnoreCase(value)) {
		continue;
		}
		final var overridePrefix = "device_config_overrides/";
		final var stagedPrefix = "staged/";
		String separator = "/";
		String prefix = "default";
		int priority = 0;
		if (name.startsWith(overridePrefix)) {
		prefix = overridePrefix;
		name = name.substring(overridePrefix.length());
		separator = ":";
		priority = 20;
		} else if (name.startsWith(stagedPrefix)) {
		prefix = stagedPrefix;
		name = name.substring(stagedPrefix.length());
		separator = "*";
		priority = 10;
		}
		final String flagPackageAndName = parseFlagPackageAndName(name, separator);
		if (flagPackageAndName == null) {
		continue;
		}
		// We ignore all settings that aren't for flags. We'll know they are for flags
		// if they correspond to flags read from the proto files.
		if (!mFlagValues.containsKey(flagPackageAndName)) {
		continue;
		}
		Slog.d(LOG_TAG, "Found " + prefix
		+ " Aconfig flag value for " + flagPackageAndName + " = " + value);
		final Integer currentPriority = flagPriority.get(flagPackageAndName);
		if (currentPriority != null && currentPriority >= priority) {
		Slog.i(LOG_TAG, "Skipping " + prefix + " flag " + flagPackageAndName
		+ " because of the existing one with priority " + currentPriority);
		continue;
		}
		flagPriority.put(flagPackageAndName, priority);
		mFlagValues.put(flagPackageAndName, Boolean.parseBoolean(value));
		}
		}
		} catch (IOException \| XmlPullParserException e) {
		Slog.e(LOG_TAG, "Failed to read Aconfig values from settings_config.xml", e);
		}
		}

		private static String parseFlagPackageAndName(String fullName, String separator) {
		int index = fullName.indexOf(separator);
		if (index < 0) {
		return null;
		}
		return fullName.substring(index + 1);
		}

		private void loadAconfigDefaultValues(byte[] fileContents) throws IOException {
		parsed_flags parsedFlags = parsed_flags.parseFrom(fileContents);
		for (parsed_flag flag : parsedFlags.parsedFlag) {
		String flagPackageAndName = flag.package_ + "." + flag.name;
		boolean flagValue = (flag.state == Aconfig.ENABLED);
		Slog.v(LOG_TAG, "Read Aconfig default flag value "
		+ flagPackageAndName + " = " + flagValue);
		mFlagValues.put(flagPackageAndName, flagValue);
		}
		}

		/**
		* Get the flag value, or null if the flag doesn't exist.
		* @param flagPackageAndName Full flag name formatted as 'package.flag'
		* @return the current value of the given Aconfig flag, or null if there is no such flag
		*/
		@Nullable
		public Boolean getFlagValue(@NonNull String flagPackageAndName) {
		Boolean value = mFlagValues.get(flagPackageAndName);
		Slog.d(LOG_TAG, "Aconfig flag value for " + flagPackageAndName + " = " + value);
		return value;
		}

		/**
		* Check if the element in {@code parser} should be skipped because of the feature flag.
		* @param parser XML parser object currently parsing an element
		* @return true if the element is disabled because of its feature flag
		*/
		public boolean skipCurrentElement(@NonNull XmlResourceParser parser) {
		if (!Flags.manifestFlagging()) {
		return false;
		}
		String featureFlag = parser.getAttributeValue(ANDROID_RES_NAMESPACE, "featureFlag");
		if (featureFlag == null) {
		return false;
		}
		featureFlag = featureFlag.strip();
		boolean negated = false;
		if (featureFlag.startsWith("!")) {
		negated = true;
		featureFlag = featureFlag.substring(1).strip();
		}
		final Boolean flagValue = getFlagValue(featureFlag);
		if (flagValue == null) {
		Slog.w(LOG_TAG, "Skipping element " + parser.getName()
		+ " due to unknown feature flag " + featureFlag);
		return true;
		}
		// Skip if flag==false && attr=="flag" OR flag==true && attr=="!flag" (negated)
		if (flagValue == negated) {
		Slog.v(LOG_TAG, "Skipping element " + parser.getName()
		+ " behind feature flag " + featureFlag + " = " + flagValue);
		return true;
		}
		return false;
		}

		/**
		* Add Aconfig flag values for testing flagging of manifest entries.
		* @param flagValues A map of flag name -> value.
		*/
		@VisibleForTesting
		public void addFlagValuesForTesting(@NonNull Map<String, Boolean> flagValues) {
		mFlagValues.putAll(flagValues);
		}
		}

core/java/com/android/internal/pm/pkg/component/ComponentParseUtils.java

+3 −0

Original line number	Diff line number	Diff line
		@@ -61,6 +61,9 @@ public class ComponentParseUtils {
		if (type != XmlPullParser.START_TAG) {
		continue;
		}
		if (ParsingPackageUtils.getAconfigFlags().skipCurrentElement(parser)) {
		continue;
		}

		final ParseResult result;
		if ("meta-data".equals(parser.getName())) {

core/java/com/android/internal/pm/pkg/component/InstallConstraintsTagParser.java

+4 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@ import android.util.ArraySet;

		import com.android.internal.R;
		import com.android.internal.pm.pkg.parsing.ParsingPackage;
		import com.android.internal.pm.pkg.parsing.ParsingPackageUtils;

		import org.xmlpull.v1.XmlPullParser;
		import org.xmlpull.v1.XmlPullParserException;
		@@ -80,6 +81,9 @@ public class InstallConstraintsTagParser {
		}
		return input.success(prefixes);
		} else if (type == XmlPullParser.START_TAG) {
		if (ParsingPackageUtils.getAconfigFlags().skipCurrentElement(parser)) {
		continue;
		}
		if (parser.getName().equals(TAG_FINGERPRINT_PREFIX)) {
		ParseResult<String> parsedPrefix =
		readFingerprintPrefixValue(input, res, parser);

core/java/com/android/internal/pm/pkg/component/ParsedActivityUtils.java

+3 −0

Original line number	Diff line number	Diff line
		@@ -393,6 +393,9 @@ public class ParsedActivityUtils {
		if (type != XmlPullParser.START_TAG) {
		continue;
		}
		if (ParsingPackageUtils.getAconfigFlags().skipCurrentElement(parser)) {
		continue;
		}

		final ParseResult result;
		if (parser.getName().equals("intent-filter")) {