Initial implementation of 'cmd device_policy'.

For now it only provides is-operation-safe, but in the long term
it will replace `dpm`

Test: adb shell cmd device_policy is-operation-safe 1

Bug: 172376923
Bug: 173381875

Change-Id: I730d9a098ba83f5813ad9f5370c680c2c89b0230

services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java

@@ -218,8 +218,10 @@ import android.os.Process;
 import android.os.RecoverySystem;
 import android.os.RemoteCallback;
 import android.os.RemoteException;
+import android.os.ResultReceiver;
 import android.os.ServiceManager;
 import android.os.ServiceSpecificException;
+import android.os.ShellCallback;
 import android.os.SystemClock;
 import android.os.SystemProperties;
 import android.os.UserHandle;
@@ -8727,6 +8729,14 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager {
         pw.decreaseIndent();
     }
 
+    @Override
+    public void onShellCommand(FileDescriptor in, FileDescriptor out, FileDescriptor err,
+            String[] args, ShellCallback callback, ResultReceiver resultReceiver) {
+        new DevicePolicyManagerServiceShellCommand(DevicePolicyManagerService.this).exec(
+                this, in, out, err, args, callback, resultReceiver);
+
+    }
+
     private String getEncryptionStatusName(int encryptionStatus) {
         switch (encryptionStatus) {
             case DevicePolicyManager.ENCRYPTION_STATUS_INACTIVE:

services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerServiceShellCommand.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2020 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.server.devicepolicy;
+
+import android.app.admin.DevicePolicyManager;
+import android.os.ShellCommand;
+
+import java.io.PrintWriter;
+import java.util.Objects;
+
+final class DevicePolicyManagerServiceShellCommand extends ShellCommand {
+
+    private static final String CMD_IS_SAFE_OPERATION = "is-operation-safe";
+
+    private final DevicePolicyManagerService mService;
+
+    DevicePolicyManagerServiceShellCommand(DevicePolicyManagerService service) {
+        mService = Objects.requireNonNull(service);
+    }
+
+    @Override
+    public void onHelp() {
+        try (PrintWriter pw = getOutPrintWriter();) {
+            pw.printf("DevicePolicyManager Service (device_policy) commands:\n\n");
+            showHelp(pw);
+        }
+    }
+
+    @Override
+    public int onCommand(String cmd) {
+        if (cmd == null) {
+            return handleDefaultCommands(cmd);
+        }
+        try (PrintWriter pw = getOutPrintWriter();) {
+            switch (cmd) {
+                case CMD_IS_SAFE_OPERATION:
+                    return runIsSafeOperation(pw);
+                default:
+                    return onInvalidCommand(pw, cmd);
+            }
+        }
+    }
+
+    private int onInvalidCommand(PrintWriter pw, String cmd) {
+        if (super.handleDefaultCommands(cmd) == 0) {
+            return 0;
+        }
+
+        pw.println("Usage: ");
+        showHelp(pw);
+        return -1;
+    }
+
+
+    private void showHelp(PrintWriter pw) {
+        pw.printf("  help\n");
+        pw.printf("    Prints this help text.\n\n");
+        pw.printf("  %s <OPERATION_ID>\n", CMD_IS_SAFE_OPERATION);
+        pw.printf("    Checks if the give operation is safe \n\n");
+    }
+
+    private int runIsSafeOperation(PrintWriter pw) {
+        int operation = Integer.parseInt(getNextArgRequired());
+        boolean safe = mService.canExecute(operation);
+        pw.printf("Operation %s is %s\n", DevicePolicyManager.operationToString(operation),
+                safe ? "SAFE" : "UNSAFE");
+        return 0;
+    }
+}