Add binder implementation to support device config shell commands from the
command line.

Test: atest SettingsProviderTest:DeviceConfigServiceTest
      Further tested manually from the command line
Bug:109919982
Bug:113101834

Change-Id: I62da11f8be9d24a2e304c10592d689ae007eb7ec
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/DeviceConfigService.java b/packages/SettingsProvider/src/com/android/providers/settings/DeviceConfigService.java
new file mode 100644
index 0000000..3520918
--- /dev/null
+++ b/packages/SettingsProvider/src/com/android/providers/settings/DeviceConfigService.java
@@ -0,0 +1,355 @@
+/*
+ * Copyright (C) 2018 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.providers.settings;
+
+import android.annotation.Nullable;
+import android.annotation.SystemApi;
+import android.app.ActivityManager;
+import android.content.IContentProvider;
+import android.net.Uri;
+import android.os.Binder;
+import android.os.Bundle;
+import android.os.Process;
+import android.os.RemoteException;
+import android.os.ResultReceiver;
+import android.os.ShellCallback;
+import android.os.ShellCommand;
+import android.provider.Settings;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Receives shell commands from the command line related to device config flags, and dispatches them
+ * to the SettingsProvider.
+ *
+ * @hide
+ */
+@SystemApi
+public final class DeviceConfigService extends Binder {
+    /**
+     * TODO(b/113100523): Move this to DeviceConfig.java when it is added, and expose it as a System
+     *     API.
+     */
+    private static final Uri CONFIG_CONTENT_URI =
+            Uri.parse("content://" + Settings.AUTHORITY + "/config");
+
+    final SettingsProvider mProvider;
+
+    public DeviceConfigService(SettingsProvider provider) {
+        mProvider = provider;
+    }
+
+    @Override
+    public void onShellCommand(FileDescriptor in, FileDescriptor out, FileDescriptor err,
+            String[] args, ShellCallback callback, ResultReceiver resultReceiver) {
+        (new MyShellCommand(mProvider)).exec(this, in, out, err, args, callback, resultReceiver);
+    }
+
+    static final class MyShellCommand extends ShellCommand {
+        final SettingsProvider mProvider;
+
+        enum CommandVerb {
+            UNSPECIFIED,
+            GET,
+            PUT,
+            DELETE,
+            LIST,
+            RESET,
+        }
+
+        MyShellCommand(SettingsProvider provider) {
+            mProvider = provider;
+        }
+
+        @Override
+        public int onCommand(String cmd) {
+            if (cmd == null || "help".equals(cmd) || "-h".equals(cmd)) {
+                onHelp();
+                return -1;
+            }
+
+            final PrintWriter perr = getErrPrintWriter();
+            boolean isValid = false;
+            CommandVerb verb;
+            if ("get".equalsIgnoreCase(cmd)) {
+                verb = CommandVerb.GET;
+            } else if ("put".equalsIgnoreCase(cmd)) {
+                verb = CommandVerb.PUT;
+            } else if ("delete".equalsIgnoreCase(cmd)) {
+                verb = CommandVerb.DELETE;
+            } else if ("list".equalsIgnoreCase(cmd)) {
+                verb = CommandVerb.LIST;
+                if (peekNextArg() == null) {
+                    isValid = true;
+                }
+            } else if ("reset".equalsIgnoreCase(cmd)) {
+                verb = CommandVerb.RESET;
+            } else {
+                // invalid
+                perr.println("Invalid command: " + cmd);
+                return -1;
+            }
+
+            int resetMode = -1;
+            boolean makeDefault = false;
+            String namespace = null;
+            String key = null;
+            String value = null;
+            String arg = null;
+            while ((arg = getNextArg()) != null) {
+                if (verb == CommandVerb.RESET) {
+                    if (resetMode == -1) {
+                        if ("untrusted_defaults".equalsIgnoreCase(arg)) {
+                            resetMode = Settings.RESET_MODE_UNTRUSTED_DEFAULTS;
+                        } else if ("untrusted_clear".equalsIgnoreCase(arg)) {
+                            resetMode = Settings.RESET_MODE_UNTRUSTED_CHANGES;
+                        } else if ("trusted_defaults".equalsIgnoreCase(arg)) {
+                            resetMode = Settings.RESET_MODE_TRUSTED_DEFAULTS;
+                        } else {
+                            // invalid
+                            perr.println("Invalid reset mode: " + arg);
+                            return -1;
+                        }
+                        if (peekNextArg() == null) {
+                            isValid = true;
+                        }
+                    } else {
+                        namespace = arg;
+                        if (peekNextArg() == null) {
+                            isValid = true;
+                        } else {
+                            // invalid
+                            perr.println("Too many arguments");
+                            return -1;
+                        }
+                    }
+                } else if (namespace == null) {
+                    namespace = arg;
+                    if (verb == CommandVerb.LIST) {
+                        if (peekNextArg() == null) {
+                            isValid = true;
+                        } else {
+                            // invalid
+                            perr.println("Too many arguments");
+                            return -1;
+                        }
+                    }
+                } else if (key == null) {
+                    key = arg;
+                    if ((verb == CommandVerb.GET || verb == CommandVerb.DELETE)) {
+                        if (peekNextArg() == null) {
+                            isValid = true;
+                        } else {
+                            // invalid
+                            perr.println("Too many arguments");
+                            return -1;
+                        }
+                    }
+                } else if (value == null) {
+                    value = arg;
+                    if (verb == CommandVerb.PUT && peekNextArg() == null) {
+                        isValid = true;
+                    }
+                } else if ("default".equalsIgnoreCase(arg)) {
+                    makeDefault = true;
+                    if (verb == CommandVerb.PUT && peekNextArg() == null) {
+                        isValid = true;
+                    } else {
+                        // invalid
+                        perr.println("Too many arguments");
+                        return -1;
+                    }
+                }
+            }
+
+            if (!isValid) {
+                perr.println("Bad arguments");
+                return -1;
+            }
+
+            final IContentProvider iprovider = mProvider.getIContentProvider();
+            final PrintWriter pout = getOutPrintWriter();
+            switch (verb) {
+                case GET:
+                    pout.println(get(iprovider, namespace, key));
+                    break;
+                case PUT:
+                    put(iprovider, namespace, key, value, makeDefault);
+                    break;
+                case DELETE:
+                    pout.println(delete(iprovider, namespace, key)
+                            ? "Successfully deleted " + key + " from " + namespace
+                            : "Failed to delete " + key + " from " + namespace);
+                    break;
+                case LIST:
+                    for (String line : list(iprovider, namespace)) {
+                        pout.println(line);
+                    }
+                    break;
+                case RESET:
+                    reset(iprovider, resetMode, namespace);
+                    break;
+                default:
+                    perr.println("Unspecified command");
+                    return -1;
+            }
+            return 0;
+        }
+
+        @Override
+        public void onHelp() {
+            PrintWriter pw = getOutPrintWriter();
+            pw.println("Device Config (device_config) commands:");
+            pw.println("  help");
+            pw.println("      Print this help text.");
+            pw.println("  get NAMESPACE KEY");
+            pw.println("      Retrieve the current value of KEY from the given NAMESPACE.");
+            pw.println("  put NAMESPACE KEY VALUE [default]");
+            pw.println("      Change the contents of KEY to VALUE for the given NAMESPACE.");
+            pw.println("      {default} to set as the default value.");
+            pw.println("  delete NAMESPACE KEY");
+            pw.println("      Delete the entry for KEY for the given NAMESPACE.");
+            pw.println("  list [NAMESPACE]");
+            pw.println("      Print all keys and values defined, optionally for the given "
+                    + "NAMESPACE.");
+            pw.println("  reset RESET_MODE [NAMESPACE]");
+            pw.println("      Reset all flag values, optionally for a NAMESPACE, according to "
+                    + "RESET_MODE.");
+            pw.println("      RESET_MODE is one of {untrusted_defaults, untrusted_clear, "
+                    + "trusted_defaults}");
+            pw.println("      NAMESPACE limits which flags are reset if provided, otherwise all "
+                    + "flags are reset");
+        }
+
+        private String get(IContentProvider provider, String namespace, String key) {
+            String compositeKey = namespace + "/" + key;
+            String result = null;
+            try {
+                Bundle args = new Bundle();
+                args.putInt(Settings.CALL_METHOD_USER_KEY,
+                        ActivityManager.getService().getCurrentUser().id);
+                Bundle b = provider.call(resolveCallingPackage(), Settings.CALL_METHOD_GET_CONFIG,
+                        compositeKey, args);
+                if (b != null) {
+                    result = b.getPairValue();
+                }
+            } catch (RemoteException e) {
+                throw new RuntimeException("Failed in IPC", e);
+            }
+            return result;
+        }
+
+        private void put(IContentProvider provider, String namespace, String key, String value,
+                boolean makeDefault) {
+            String compositeKey = namespace + "/" + key;
+
+            try {
+                Bundle args = new Bundle();
+                args.putString(Settings.NameValueTable.VALUE, value);
+                args.putInt(Settings.CALL_METHOD_USER_KEY,
+                        ActivityManager.getService().getCurrentUser().id);
+                if (makeDefault) {
+                    args.putBoolean(Settings.CALL_METHOD_MAKE_DEFAULT_KEY, true);
+                }
+                provider.call(resolveCallingPackage(), Settings.CALL_METHOD_PUT_CONFIG,
+                        compositeKey, args);
+            } catch (RemoteException e) {
+                throw new RuntimeException("Failed in IPC", e);
+            }
+        }
+
+        private boolean delete(IContentProvider provider, String namespace, String key) {
+            String compositeKey = namespace + "/" + key;
+            boolean success;
+
+            try {
+                Bundle args = new Bundle();
+                args.putInt(Settings.CALL_METHOD_USER_KEY,
+                        ActivityManager.getService().getCurrentUser().id);
+                Bundle b = provider.call(resolveCallingPackage(),
+                        Settings.CALL_METHOD_DELETE_CONFIG, compositeKey, args);
+                success = (b != null && b.getInt(SettingsProvider.RESULT_ROWS_DELETED) == 1);
+            } catch (RemoteException e) {
+                throw new RuntimeException("Failed in IPC", e);
+            }
+            return success;
+        }
+
+        private List<String> list(IContentProvider provider, @Nullable String namespace) {
+            final ArrayList<String> lines = new ArrayList<>();
+
+            try {
+                Bundle args = new Bundle();
+                args.putInt(Settings.CALL_METHOD_USER_KEY,
+                        ActivityManager.getService().getCurrentUser().id);
+                if (namespace != null) {
+                    args.putString(Settings.CALL_METHOD_PREFIX_KEY, namespace);
+                }
+                Bundle b = provider.call(resolveCallingPackage(),
+                        Settings.CALL_METHOD_LIST_CONFIG, null, args);
+                if (b != null) {
+                    Map<String, String> flagsToValues =
+                            (HashMap) b.getSerializable(Settings.NameValueTable.VALUE);
+                    for (String key : flagsToValues.keySet()) {
+                        lines.add(key + "=" + flagsToValues.get(key));
+                    }
+                }
+
+                Collections.sort(lines);
+            } catch (RemoteException e) {
+                throw new RuntimeException("Failed in IPC", e);
+            }
+            return lines;
+        }
+
+        private void reset(IContentProvider provider, int resetMode, @Nullable String namespace) {
+            try {
+                Bundle args = new Bundle();
+                args.putInt(Settings.CALL_METHOD_USER_KEY,
+                        ActivityManager.getService().getCurrentUser().id);
+                args.putInt(Settings.CALL_METHOD_RESET_MODE_KEY, resetMode);
+                args.putString(Settings.CALL_METHOD_PREFIX_KEY, namespace);
+                provider.call(
+                        resolveCallingPackage(), Settings.CALL_METHOD_RESET_CONFIG, null, args);
+            } catch (RemoteException e) {
+                throw new RuntimeException("Failed in IPC", e);
+            }
+        }
+
+        private static String resolveCallingPackage() {
+            switch (Binder.getCallingUid()) {
+                case Process.ROOT_UID: {
+                    return "root";
+                }
+
+                case Process.SHELL_UID: {
+                    return "com.android.shell";
+                }
+
+                default: {
+                    return null;
+                }
+            }
+        }
+    }
+}
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
index 140a5a3..424368d 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
@@ -335,6 +335,7 @@
             startWatchingUserRestrictionChanges();
         });
         ServiceManager.addService("settings", new SettingsService(this));
+        ServiceManager.addService("device_config", new DeviceConfigService(this));
         return true;
     }
 
diff --git a/packages/SettingsProvider/test/src/com/android/providers/settings/DeviceConfigServiceTest.java b/packages/SettingsProvider/test/src/com/android/providers/settings/DeviceConfigServiceTest.java
new file mode 100644
index 0000000..59de6a7e
--- /dev/null
+++ b/packages/SettingsProvider/test/src/com/android/providers/settings/DeviceConfigServiceTest.java
@@ -0,0 +1,236 @@
+/*
+ * Copyright (C) 2018 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.providers.settings;
+
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertNull;
+
+import static org.junit.Assert.assertNotNull;
+
+import android.content.ContentResolver;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.Settings;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import libcore.io.Streams;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Tests for {@link DeviceConfigService}.
+ */
+@RunWith(AndroidJUnit4.class)
+public class DeviceConfigServiceTest {
+    /**
+     * TODO(b/113100523): Move this to DeviceConfig.java when it is added, and expose it as a System
+     *     API.
+     */
+    private static final Uri CONFIG_CONTENT_URI =
+            Uri.parse("content://" + Settings.AUTHORITY + "/config");
+    private static final String sNamespace = "namespace1";
+    private static final String sKey = "key1";
+    private static final String sValue = "value1";
+
+    private ContentResolver mContentResolver;
+
+    @Before
+    public void setUp() {
+        mContentResolver = InstrumentationRegistry.getContext().getContentResolver();
+    }
+
+    @After
+    public void cleanUp() {
+        deleteFromContentProvider(mContentResolver, sNamespace, sKey);
+    }
+
+    @Test
+    public void testPut() throws Exception {
+        final String newNamespace = "namespace2";
+        final String newValue = "value2";
+
+        String result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        assertNull(result);
+
+        try {
+            executeShellCommand("device_config put " + sNamespace + " " + sKey + " " + sValue);
+            executeShellCommand("device_config put " + newNamespace + " " + sKey + " " + newValue);
+
+            result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+            assertEquals(sValue, result);
+            result = getFromContentProvider(mContentResolver, newNamespace, sKey);
+            assertEquals(newValue, result);
+        } finally {
+            deleteFromContentProvider(mContentResolver, newNamespace, sKey);
+        }
+    }
+
+    @Test
+    public void testPut_invalidArgs() throws Exception {
+        // missing sNamespace
+        executeShellCommand("device_config put " + sKey + " " + sValue);
+        String result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // still null
+        assertNull(result);
+
+        // too many arguments
+        executeShellCommand(
+                "device_config put " + sNamespace + " " + sKey + " " + sValue + " extra_arg");
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // still null
+        assertNull(result);
+    }
+
+    @Test
+    public void testDelete() throws Exception {
+        final String newNamespace = "namespace2";
+
+        putWithContentProvider(mContentResolver, sNamespace, sKey, sValue);
+        putWithContentProvider(mContentResolver, newNamespace, sKey, sValue);
+        String result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        assertEquals(sValue, result);
+        result = getFromContentProvider(mContentResolver, newNamespace, sKey);
+        assertEquals(sValue, result);
+
+        try {
+            executeShellCommand("device_config delete " + sNamespace + " " + sKey);
+            // sKey is deleted from sNamespace
+            result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+            assertNull(result);
+            // sKey is not deleted from newNamespace
+            result = getFromContentProvider(mContentResolver, newNamespace, sKey);
+            assertEquals(sValue, result);
+        } finally {
+            deleteFromContentProvider(mContentResolver, newNamespace, sKey);
+        }
+    }
+
+    @Test
+    public void testDelete_invalidArgs() throws Exception {
+        putWithContentProvider(mContentResolver, sNamespace, sKey, sValue);
+        String result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        assertEquals(sValue, result);
+
+        // missing sNamespace
+        executeShellCommand("device_config delete " + sKey);
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // sValue was not deleted
+        assertEquals(sValue, result);
+
+        // too many arguments
+        executeShellCommand("device_config delete " + sNamespace + " " + sKey + " extra_arg");
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // sValue was not deleted
+        assertEquals(sValue, result);
+    }
+
+    @Test
+    public void testReset_setUntrustedDefault() throws Exception {
+        String newValue = "value2";
+
+        // make sValue the untrusted default (set by root)
+        executeShellCommand(
+                "device_config put " + sNamespace + " " + sKey + " " + sValue + " default");
+        // make newValue the current value
+        executeShellCommand(
+                "device_config put " + sNamespace + " " + sKey + " " + newValue);
+        String result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        assertEquals(newValue, result);
+
+        executeShellCommand("device_config reset untrusted_defaults " + sNamespace);
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // back to the default
+        assertEquals(sValue, result);
+
+        executeShellCommand("device_config reset trusted_defaults " + sNamespace);
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // not trusted default was set
+        assertNull(result);
+    }
+
+    @Test
+    public void testReset_setTrustedDefault() throws Exception {
+        String newValue = "value2";
+
+        // make sValue the trusted default (set by system)
+        putWithContentProvider(mContentResolver, sNamespace, sKey, sValue, true);
+        // make newValue the current value
+        executeShellCommand(
+                "device_config put " + sNamespace + " " + sKey + " " + newValue);
+        String result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        assertEquals(newValue, result);
+
+        executeShellCommand("device_config reset untrusted_defaults " + sNamespace);
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // back to the default
+        assertEquals(sValue, result);
+
+        executeShellCommand("device_config reset trusted_defaults " + sNamespace);
+        result = getFromContentProvider(mContentResolver, sNamespace, sKey);
+        // our trusted default is still set
+        assertEquals(sValue, result);
+    }
+
+    private static void executeShellCommand(String command) throws IOException {
+        InputStream is = new FileInputStream(InstrumentationRegistry.getInstrumentation()
+                .getUiAutomation().executeShellCommand(command).getFileDescriptor());
+        Streams.readFully(is);
+    }
+
+    private static void putWithContentProvider(ContentResolver resolver, String namespace,
+            String key, String value) {
+        putWithContentProvider(resolver, namespace, key, value, false);
+    }
+
+    private static void putWithContentProvider(ContentResolver resolver, String namespace,
+            String key, String value, boolean makeDefault) {
+        String compositeName = namespace + "/" + key;
+        Bundle args = new Bundle();
+        args.putString(Settings.NameValueTable.VALUE, value);
+        if (makeDefault) {
+            args.putBoolean(Settings.CALL_METHOD_MAKE_DEFAULT_KEY, true);
+        }
+        resolver.call(
+                CONFIG_CONTENT_URI, Settings.CALL_METHOD_PUT_CONFIG, compositeName, args);
+    }
+
+    private static String getFromContentProvider(ContentResolver resolver, String namespace,
+            String key) {
+        String compositeName = namespace + "/" + key;
+        Bundle result = resolver.call(
+                CONFIG_CONTENT_URI, Settings.CALL_METHOD_GET_CONFIG, compositeName, null);
+        assertNotNull(result);
+        return result.getString(Settings.NameValueTable.VALUE);
+    }
+
+    private static boolean deleteFromContentProvider(ContentResolver resolver, String namespace,
+            String key) {
+        String compositeName = namespace + "/" + key;
+        Bundle result = resolver.call(
+                CONFIG_CONTENT_URI, Settings.CALL_METHOD_DELETE_CONFIG, compositeName, null);
+        assertNotNull(result);
+        return compositeName.equals(result.getString(Settings.NameValueTable.VALUE));
+    }
+}