1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.os;
18
19import android.util.Log;
20
21import com.android.internal.os.IShellCallback;
22
23/**
24 * Special-purpose API for use with {@link IBinder#shellCommand IBinder.shellCommand} for
25 * performing operations back on the invoking shell.
26 * @hide
27 */
28public class ShellCallback implements Parcelable {
29    final static String TAG = "ShellCallback";
30
31    final static boolean DEBUG = false;
32
33    final boolean mLocal;
34
35    IShellCallback mShellCallback;
36
37    class MyShellCallback extends IShellCallback.Stub {
38        public ParcelFileDescriptor openOutputFile(String path, String seLinuxContext) {
39            return onOpenOutputFile(path, seLinuxContext);
40        }
41    }
42
43    /**
44     * Create a new ShellCallback to receive requests.
45     */
46    public ShellCallback() {
47        mLocal = true;
48    }
49
50    /**
51     * Ask the shell to open a file for writing.  This will truncate the file if it
52     * already exists.  It will create the file if it doesn't exist.
53     * @param path Path of the file to be opened/created.
54     * @param seLinuxContext Optional SELinux context that must be allowed to have
55     * access to the file; if null, nothing is required.
56     */
57    public ParcelFileDescriptor openOutputFile(String path, String seLinuxContext) {
58        if (DEBUG) Log.d(TAG, "openOutputFile " + this + ": mLocal=" + mLocal
59                + " mShellCallback=" + mShellCallback);
60
61        if (mLocal) {
62            return onOpenOutputFile(path, seLinuxContext);
63        }
64
65        if (mShellCallback != null) {
66            try {
67                return mShellCallback.openOutputFile(path, seLinuxContext);
68            } catch (RemoteException e) {
69                Log.w(TAG, "Failure opening " + path, e);
70            }
71        }
72        return null;
73    }
74
75    public ParcelFileDescriptor onOpenOutputFile(String path, String seLinuxContext) {
76        return null;
77    }
78
79    public static void writeToParcel(ShellCallback callback, Parcel out) {
80        if (callback == null) {
81            out.writeStrongBinder(null);
82        } else {
83            callback.writeToParcel(out, 0);
84        }
85    }
86
87    public int describeContents() {
88        return 0;
89    }
90
91    public void writeToParcel(Parcel out, int flags) {
92        synchronized (this) {
93            if (mShellCallback == null) {
94                mShellCallback = new MyShellCallback();
95            }
96            out.writeStrongBinder(mShellCallback.asBinder());
97        }
98    }
99
100    ShellCallback(Parcel in) {
101        mLocal = false;
102        mShellCallback = IShellCallback.Stub.asInterface(in.readStrongBinder());
103    }
104
105    public static final Parcelable.Creator<ShellCallback> CREATOR
106            = new Parcelable.Creator<ShellCallback>() {
107        public ShellCallback createFromParcel(Parcel in) {
108            return new ShellCallback(in);
109        }
110        public ShellCallback[] newArray(int size) {
111            return new ShellCallback[size];
112        }
113    };
114}
115