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 
17 import dalvik.system.PathClassLoader;
18 import dalvik.system.VMDebug;
19 import java.io.BufferedInputStream;
20 import java.io.BufferedOutputStream;
21 import java.io.FileInputStream;
22 import java.io.FileOutputStream;
23 import java.io.File;
24 import java.io.IOException;
25 
26 public class Main {
main(String[] args)27   public static void main(String[] args) throws Exception {
28     System.loadLibrary(args[0]);
29     System.out.println("Hello, world!");
30     String agent = null;
31     // By default allow debugging
32     boolean debugging_allowed = true;
33     for(String a : args) {
34       if(a.startsWith("agent:")) {
35         agent = a.substring(6);
36       } else if (a.equals("disallow-debugging")) {
37         debugging_allowed = false;
38       }
39     }
40     if (agent == null) {
41       throw new Error("Could not find agent: argument!");
42     }
43     setDebuggingAllowed(debugging_allowed);
44     // Setup is finished. Try to attach agent in 2 ways.
45     try {
46       VMDebug.attachAgent(agent);
47     } catch(SecurityException e) {
48       System.out.println(e.getMessage());
49     }
50     attachWithClassLoader(args);
51     System.out.println("Goodbye!");
52   }
53 
setDebuggingAllowed(boolean val)54   private static native void setDebuggingAllowed(boolean val);
55 
attachWithClassLoader(String[] args)56   private static void attachWithClassLoader(String[] args) throws Exception {
57     for(String a : args) {
58       if(a.startsWith("agent:")) {
59         String agentName = a.substring(6, a.indexOf('='));
60         File tmp = null;
61         try {
62           tmp = File.createTempFile("lib", ".so");
63           prepare(agentName, tmp);
64 
65           String newAgentName = tmp.getName();
66           String agent = a.substring(6).replace(agentName, newAgentName);
67 
68           ClassLoader cl = new PathClassLoader("", tmp.getParentFile().getAbsolutePath(),
69               Main.class.getClassLoader());
70           try {
71             VMDebug.attachAgent(agent, cl);
72           } catch(SecurityException e) {
73             System.out.println(e.getMessage());
74           }
75         } catch (Exception e) {
76           e.printStackTrace(System.out);
77         } finally {
78           if (tmp != null) {
79             tmp.delete();
80           }
81         }
82       }
83     }
84   }
85 
prepare(String in, File tmp)86   private static void prepare(String in, File tmp) throws Exception {
87     // Find the original.
88     File orig = find(in);
89     if (orig == null) {
90       throw new RuntimeException("Could not find " + in);
91     }
92     // Copy the original.
93     {
94       BufferedInputStream bis = new BufferedInputStream(new FileInputStream(orig));
95       BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(tmp));
96       byte[] buf = new byte[16 * 1024];
97       for (;;) {
98         int r = bis.read(buf, 0, buf.length);
99         if (r < 0) {
100           break;
101         } else if (r > 0) {
102           bos.write(buf, 0, r);
103         }
104       }
105       bos.close();
106       bis.close();
107     }
108   }
109 
find(String in)110   private static File find(String in) {
111     String libraryPath = System.getProperty("java.library.path");
112     for (String path : libraryPath.split(":")) {
113       File f = new File(path + "/" + in);
114       if (f.exists()) {
115         return f;
116       }
117     }
118     return null;
119   }
120 }
121