/*
 * Copyright (C) 2021 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.permission.util;

import android.annotation.NonNull;
import android.annotation.UserIdInt;
import android.content.Context;
import android.os.Binder;
import android.os.Process;
import android.os.UserHandle;
import android.os.UserManager;

import com.android.internal.util.Preconditions;
import com.android.permission.compat.UserHandleCompat;

/** Utility class to deal with Android permissions. */
public final class PermissionUtils {

    private PermissionUtils() {}

    /** Enforces cross user permission for the calling UID and the given {@code userId}. */
    public static void enforceCrossUserPermission(@UserIdInt int userId, boolean allowAll,
            @NonNull String message, @NonNull Context context) {
        final int callingUid = Binder.getCallingUid();
        final int callingUserId = UserHandleCompat.getUserId(callingUid);
        if (userId == callingUserId) {
            return;
        }
        Preconditions.checkArgument(userId >= UserHandleCompat.USER_SYSTEM
                || (allowAll && userId == UserHandleCompat.USER_ALL), "Invalid user " + userId);
        context.enforceCallingOrSelfPermission(
                android.Manifest.permission.INTERACT_ACROSS_USERS_FULL, message);
        if (callingUid == Process.SHELL_UID && userId >= UserHandleCompat.USER_SYSTEM) {
            UserManager userManager = context.getSystemService(UserManager.class);
            if (userManager.hasUserRestrictionForUser(UserManager.DISALLOW_DEBUGGING_FEATURES,
                    UserHandle.of(userId))) {
                throw new SecurityException("Shell does not have permission to access user "
                        + userId);
            }
        }
    }
}