WrapperInit.java revision 6090995951c6e2e4dcf38102f01793f8a94166e1 
1/*
2 * Copyright (C) 2011 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 com.android.internal.os;
18
19import android.os.Process;
20import android.util.Slog;
21
22import java.io.DataOutputStream;
23import java.io.FileDescriptor;
24import java.io.FileOutputStream;
25import java.io.IOException;
26
27import libcore.io.IoUtils;
28
29import dalvik.system.Zygote;
30
31/**
32 * Startup class for the wrapper process.
33 * @hide
34 */
35public class WrapperInit {
36    private final static String TAG = "AndroidRuntime";
37
38    /**
39     * Class not instantiable.
40     */
41    private WrapperInit() {
42    }
43
44    /**
45     * The main function called when starting a runtime application through a
46     * wrapper process instead of by forking Zygote.
47     *
48     * The first argument specifies the file descriptor for a pipe that should receive
49     * the pid of this process, or 0 if none.
50     *
51     * The second argument is the target SDK version for the app.
52     *
53     * The remaining arguments are passed to the runtime.
54     *
55     * @param args The command-line arguments.
56     */
57    public static void main(String[] args) {
58        try {
59            // Parse our mandatory arguments.
60            int fdNum = Integer.parseInt(args[0], 10);
61            int targetSdkVersion = Integer.parseInt(args[1], 10);
62
63            // Tell the Zygote what our actual PID is (since it only knows about the
64            // wrapper that it directly forked).
65            if (fdNum != 0) {
66                try {
67                    FileDescriptor fd = ZygoteInit.createFileDescriptor(fdNum);
68                    DataOutputStream os = new DataOutputStream(new FileOutputStream(fd));
69                    os.writeInt(Process.myPid());
70                    os.close();
71                    IoUtils.closeQuietly(fd);
72                } catch (IOException ex) {
73                    Slog.d(TAG, "Could not write pid of wrapped process to Zygote pipe.", ex);
74                }
75            }
76
77            // Mimic Zygote preloading.
78            ZygoteInit.preload();
79
80            // Launch the application.
81            String[] runtimeArgs = new String[args.length - 2];
82            System.arraycopy(args, 2, runtimeArgs, 0, runtimeArgs.length);
83            RuntimeInit.wrapperInit(targetSdkVersion, runtimeArgs);
84        } catch (ZygoteInit.MethodAndArgsCaller caller) {
85            caller.run();
86        }
87    }
88
89    /**
90     * Executes a runtime application with a wrapper command.
91     * This method never returns.
92     *
93     * @param invokeWith The wrapper command.
94     * @param niceName The nice name for the application, or null if none.
95     * @param targetSdkVersion The target SDK version for the app.
96     * @param pipeFd The pipe to which the application's pid should be written, or null if none.
97     * @param args Arguments for {@link RuntimeInit.main}.
98     */
99    public static void execApplication(String invokeWith, String niceName,
100            int targetSdkVersion, FileDescriptor pipeFd, String[] args) {
101        StringBuilder command = new StringBuilder(invokeWith);
102        command.append(" /system/bin/app_process /system/bin --application");
103        if (niceName != null) {
104            command.append(" '--nice-name=").append(niceName).append("'");
105        }
106        command.append(" com.android.internal.os.WrapperInit ");
107        command.append(pipeFd != null ? pipeFd.getInt$() : 0);
108        command.append(' ');
109        command.append(targetSdkVersion);
110        Zygote.appendQuotedShellArgs(command, args);
111        Zygote.execShell(command.toString());
112    }
113
114    /**
115     * Executes a standalone application with a wrapper command.
116     * This method never returns.
117     *
118     * @param invokeWith The wrapper command.
119     * @param classPath The class path.
120     * @param className The class name to invoke.
121     * @param args Arguments for the main() method of the specified class.
122     */
123    public static void execStandalone(String invokeWith, String classPath, String className,
124            String[] args) {
125        StringBuilder command = new StringBuilder(invokeWith);
126        command.append(" /system/bin/dalvikvm -classpath '").append(classPath);
127        command.append("' ").append(className);
128        Zygote.appendQuotedShellArgs(command, args);
129        Zygote.execShell(command.toString());
130    }
131}
132