src/com/saurik/backport/Hook.java

   1 /* Backport - Bring New Fixes to old Androids
   2  * Copyright (C) 2013  Jay Freeman (saurik)
   3 */
   4
   5 /* GNU Lesser General Public License, Version 3 {{{ */
   6 /*
   7  * Substrate is free software: you can redistribute it and/or modify it under
   8  * the terms of the GNU Lesser General Public License as published by the
   9  * Free Software Foundation, either version 3 of the License, or (at your
  10  * option) any later version.
  11  *
  12  * Substrate is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15  * License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
  19 **/
  20 /* }}} */
  21
  22 package com.saurik.backport;
  23
  24 import java.lang.reflect.Field;
  25 import java.lang.reflect.Method;
  26
  27 import java.util.LinkedHashMap;
  28
  29 import java.util.jar.JarFile;
  30
  31 import java.util.zip.ZipEntry;
  32 import java.util.zip.ZipException;
  33 import java.util.zip.ZipFile;
  34
  35 import android.util.Log;
  36
  37 import com.saurik.substrate.MS;
  38
  39 public class Hook {
  40     private static class WrongException
  41         extends RuntimeException
  42     {
  43         public WrongException(Throwable cause) {
  44             super(cause);
  45         }
  46     }
  47
  48     public static void initialize() {
  49         MS.hookClassLoad("java.util.zip.ZipFile", new MS.ClassLoadHook() {
  50             public void classLoaded(Class<?> ZipFile$) {
  51                 Field entries = null; {
  52                     if (entries == null) try {
  53                         entries = ZipFile$.getDeclaredField("entries");
  54                     } catch (NoSuchFieldException e) {}
  55
  56                     if (entries == null) try {
  57                         entries = ZipFile$.getDeclaredField("mEntries");
  58                     } catch (NoSuchFieldException e) {}
  59                 }
  60
  61                 if (entries == null)
  62                     return;
  63                 final Field ZipFile$entries = entries;
  64                 ZipFile$entries.setAccessible(true);
  65
  66                 final Method ZipFile$readCentralDir; try {
  67                     ZipFile$readCentralDir = ZipFile$.getDeclaredMethod("readCentralDir");
  68                 } catch (NoSuchMethodException e) {
  69                     Log.e("Backport", "ZipFile$readCentralDir", e);
  70                     return;
  71                 }
  72
  73                 MS.hookMethod(ZipFile$, ZipFile$readCentralDir,
  74                     new MS.MethodAlteration<ZipFile, Void>() {
  75                         public Void invoked(ZipFile thiz, Object... args)
  76                             throws Throwable
  77                         {
  78                             ZipFile$entries.set(thiz, new LinkedHashMap<String, ZipEntry>() {
  79                                 public ZipEntry put(String key, ZipEntry value) {
  80                                     if (super.put(key, value) != null)
  81                                         throw new WrongException(new ZipException("Duplicate entry name: " + key));
  82                                     return null;
  83                                 }
  84                             });
  85
  86                             try {
  87                                 return invoke(thiz, args);
  88                             } catch (WrongException wrong) {
  89                                 throw wrong.getCause();
  90                             }
  91                         }
  92                     }
  93                 );
  94             }
  95         });
  96     }
  97 }