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      1 /* Copyright (C) 2017 The Android Open Source Project
      2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
      3  *
      4  * This file implements interfaces from the file jvmti.h. This implementation
      5  * is licensed under the same terms as the file jvmti.h.  The
      6  * copyright and license information for the file jvmti.h follows.
      7  *
      8  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
      9  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     10  *
     11  * This code is free software; you can redistribute it and/or modify it
     12  * under the terms of the GNU General Public License version 2 only, as
     13  * published by the Free Software Foundation.  Oracle designates this
     14  * particular file as subject to the "Classpath" exception as provided
     15  * by Oracle in the LICENSE file that accompanied this code.
     16  *
     17  * This code is distributed in the hope that it will be useful, but WITHOUT
     18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     20  * version 2 for more details (a copy is included in the LICENSE file that
     21  * accompanied this code).
     22  *
     23  * You should have received a copy of the GNU General Public License version
     24  * 2 along with this work; if not, write to the Free Software Foundation,
     25  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     26  *
     27  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     28  * or visit www.oracle.com if you need additional information or have any
     29  * questions.
     30  */
     31 
     32 #include "ti_class_loader.h"
     33 
     34 #include <limits>
     35 
     36 #include "android-base/stringprintf.h"
     37 
     38 #include "art_field-inl.h"
     39 #include "art_jvmti.h"
     40 #include "base/logging.h"
     41 #include "dex_file.h"
     42 #include "dex_file_types.h"
     43 #include "events-inl.h"
     44 #include "gc/allocation_listener.h"
     45 #include "gc/heap.h"
     46 #include "instrumentation.h"
     47 #include "jit/jit.h"
     48 #include "jit/jit_code_cache.h"
     49 #include "jni_env_ext-inl.h"
     50 #include "jvmti_allocator.h"
     51 #include "mirror/class.h"
     52 #include "mirror/class_ext.h"
     53 #include "mirror/object.h"
     54 #include "nativehelper/ScopedLocalRef.h"
     55 #include "object_lock.h"
     56 #include "runtime.h"
     57 #include "transform.h"
     58 
     59 namespace openjdkjvmti {
     60 
     61 bool ClassLoaderHelper::AddToClassLoader(art::Thread* self,
     62                                          art::Handle<art::mirror::ClassLoader> loader,
     63                                          const art::DexFile* dex_file) {
     64   art::ScopedObjectAccessUnchecked soa(self);
     65   art::StackHandleScope<3> hs(self);
     66   if (art::ClassLinker::IsBootClassLoader(soa, loader.Get())) {
     67     art::Runtime::Current()->GetClassLinker()->AppendToBootClassPath(self, *dex_file);
     68     return true;
     69   }
     70   art::Handle<art::mirror::Object> java_dex_file_obj(
     71       hs.NewHandle(FindSourceDexFileObject(self, loader)));
     72   if (java_dex_file_obj.IsNull()) {
     73     return false;
     74   }
     75   art::Handle<art::mirror::LongArray> old_cookie(hs.NewHandle(GetDexFileCookie(java_dex_file_obj)));
     76   art::Handle<art::mirror::LongArray> cookie(hs.NewHandle(
     77       AllocateNewDexFileCookie(self, old_cookie, dex_file)));
     78   if (cookie.IsNull()) {
     79     return false;
     80   }
     81   art::ScopedAssertNoThreadSuspension nts("Replacing cookie fields in j.l.DexFile object");
     82   UpdateJavaDexFile(java_dex_file_obj.Get(), cookie.Get());
     83   return true;
     84 }
     85 
     86 void ClassLoaderHelper::UpdateJavaDexFile(art::ObjPtr<art::mirror::Object> java_dex_file,
     87                                           art::ObjPtr<art::mirror::LongArray> new_cookie) {
     88   art::ArtField* internal_cookie_field = java_dex_file->GetClass()->FindDeclaredInstanceField(
     89       "mInternalCookie", "Ljava/lang/Object;");
     90   art::ArtField* cookie_field = java_dex_file->GetClass()->FindDeclaredInstanceField(
     91       "mCookie", "Ljava/lang/Object;");
     92   CHECK(internal_cookie_field != nullptr);
     93   art::ObjPtr<art::mirror::LongArray> orig_internal_cookie(
     94       internal_cookie_field->GetObject(java_dex_file)->AsLongArray());
     95   art::ObjPtr<art::mirror::LongArray> orig_cookie(
     96       cookie_field->GetObject(java_dex_file)->AsLongArray());
     97   internal_cookie_field->SetObject<false>(java_dex_file, new_cookie);
     98   if (!orig_cookie.IsNull()) {
     99     cookie_field->SetObject<false>(java_dex_file, new_cookie);
    100   }
    101 }
    102 
    103 art::ObjPtr<art::mirror::LongArray> ClassLoaderHelper::GetDexFileCookie(
    104     art::Handle<art::mirror::Object> java_dex_file_obj) {
    105   // mCookie is nulled out if the DexFile has been closed but mInternalCookie sticks around until
    106   // the object is finalized. Since they always point to the same array if mCookie is not null we
    107   // just use the mInternalCookie field. We will update one or both of these fields later.
    108   art::ArtField* internal_cookie_field = java_dex_file_obj->GetClass()->FindDeclaredInstanceField(
    109       "mInternalCookie", "Ljava/lang/Object;");
    110   // TODO Add check that mCookie is either null or same as mInternalCookie
    111   CHECK(internal_cookie_field != nullptr);
    112   return internal_cookie_field->GetObject(java_dex_file_obj.Get())->AsLongArray();
    113 }
    114 
    115 art::ObjPtr<art::mirror::LongArray> ClassLoaderHelper::AllocateNewDexFileCookie(
    116     art::Thread* self,
    117     art::Handle<art::mirror::LongArray> cookie,
    118     const art::DexFile* dex_file) {
    119   art::StackHandleScope<1> hs(self);
    120   CHECK(cookie != nullptr);
    121   CHECK_GE(cookie->GetLength(), 1);
    122   art::Handle<art::mirror::LongArray> new_cookie(
    123       hs.NewHandle(art::mirror::LongArray::Alloc(self, cookie->GetLength() + 1)));
    124   if (new_cookie == nullptr) {
    125     self->AssertPendingOOMException();
    126     return nullptr;
    127   }
    128   // Copy the oat-dex field at the start.
    129   new_cookie->SetWithoutChecks<false>(0, cookie->GetWithoutChecks(0));
    130   // This must match the casts in runtime/native/dalvik_system_DexFile.cc:ConvertDexFilesToJavaArray
    131   new_cookie->SetWithoutChecks<false>(
    132       1, static_cast<int64_t>(reinterpret_cast<uintptr_t>(dex_file)));
    133   new_cookie->Memcpy(2, cookie.Get(), 1, cookie->GetLength() - 1);
    134   return new_cookie.Get();
    135 }
    136 
    137 // TODO This should return the actual source java.lang.DexFile object for the klass being loaded.
    138 art::ObjPtr<art::mirror::Object> ClassLoaderHelper::FindSourceDexFileObject(
    139     art::Thread* self, art::Handle<art::mirror::ClassLoader> loader) {
    140   const char* dex_path_list_element_array_name = "[Ldalvik/system/DexPathList$Element;";
    141   const char* dex_path_list_element_name = "Ldalvik/system/DexPathList$Element;";
    142   const char* dex_file_name = "Ldalvik/system/DexFile;";
    143   const char* dex_path_list_name = "Ldalvik/system/DexPathList;";
    144   const char* dex_class_loader_name = "Ldalvik/system/BaseDexClassLoader;";
    145 
    146   CHECK(!self->IsExceptionPending());
    147   art::StackHandleScope<5> hs(self);
    148   art::ClassLinker* class_linker = art::Runtime::Current()->GetClassLinker();
    149 
    150   art::Handle<art::mirror::ClassLoader> null_loader(hs.NewHandle<art::mirror::ClassLoader>(
    151       nullptr));
    152   art::Handle<art::mirror::Class> base_dex_loader_class(hs.NewHandle(class_linker->FindClass(
    153       self, dex_class_loader_name, null_loader)));
    154 
    155   // Get all the ArtFields so we can look in the BaseDexClassLoader
    156   art::ArtField* path_list_field = base_dex_loader_class->FindDeclaredInstanceField(
    157       "pathList", dex_path_list_name);
    158   CHECK(path_list_field != nullptr);
    159 
    160   art::ArtField* dex_path_list_element_field =
    161       class_linker->FindClass(self, dex_path_list_name, null_loader)
    162         ->FindDeclaredInstanceField("dexElements", dex_path_list_element_array_name);
    163   CHECK(dex_path_list_element_field != nullptr);
    164 
    165   art::ArtField* element_dex_file_field =
    166       class_linker->FindClass(self, dex_path_list_element_name, null_loader)
    167         ->FindDeclaredInstanceField("dexFile", dex_file_name);
    168   CHECK(element_dex_file_field != nullptr);
    169 
    170   // Check if loader is a BaseDexClassLoader
    171   art::Handle<art::mirror::Class> loader_class(hs.NewHandle(loader->GetClass()));
    172   // Currently only base_dex_loader is allowed to actually define classes but if this changes in the
    173   // future we should make sure to support all class loader types.
    174   if (!loader_class->IsSubClass(base_dex_loader_class.Get())) {
    175     LOG(ERROR) << "The classloader is not a BaseDexClassLoader which is currently the only "
    176                << "supported class loader type!";
    177     return nullptr;
    178   }
    179   // Start navigating the fields of the loader (now known to be a BaseDexClassLoader derivative)
    180   art::Handle<art::mirror::Object> path_list(
    181       hs.NewHandle(path_list_field->GetObject(loader.Get())));
    182   CHECK(path_list != nullptr);
    183   CHECK(!self->IsExceptionPending());
    184   art::Handle<art::mirror::ObjectArray<art::mirror::Object>> dex_elements_list(hs.NewHandle(
    185       dex_path_list_element_field->GetObject(path_list.Get())->
    186       AsObjectArray<art::mirror::Object>()));
    187   CHECK(!self->IsExceptionPending());
    188   CHECK(dex_elements_list != nullptr);
    189   size_t num_elements = dex_elements_list->GetLength();
    190   // Iterate over the DexPathList$Element to find the right one
    191   for (size_t i = 0; i < num_elements; i++) {
    192     art::ObjPtr<art::mirror::Object> current_element = dex_elements_list->Get(i);
    193     CHECK(!current_element.IsNull());
    194     // TODO It would be cleaner to put the art::DexFile into the dalvik.system.DexFile the class
    195     // comes from but it is more annoying because we would need to find this class. It is not
    196     // necessary for proper function since we just need to be in front of the classes old dex file
    197     // in the path.
    198     art::ObjPtr<art::mirror::Object> first_dex_file(
    199         element_dex_file_field->GetObject(current_element));
    200     if (!first_dex_file.IsNull()) {
    201       return first_dex_file;
    202     }
    203   }
    204   return nullptr;
    205 }
    206 
    207 }  // namespace openjdkjvmti
    208