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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/array_slice.h"
     41 #include "base/logging.h"
     42 #include "dex_file.h"
     43 #include "dex_file_types.h"
     44 #include "events-inl.h"
     45 #include "gc/allocation_listener.h"
     46 #include "gc/heap.h"
     47 #include "instrumentation.h"
     48 #include "jit/jit.h"
     49 #include "jit/jit_code_cache.h"
     50 #include "jni_env_ext-inl.h"
     51 #include "jvmti_allocator.h"
     52 #include "mirror/class.h"
     53 #include "mirror/class_ext.h"
     54 #include "mirror/object.h"
     55 #include "object_lock.h"
     56 #include "runtime.h"
     57 #include "ScopedLocalRef.h"
     58 #include "transform.h"
     59 
     60 namespace openjdkjvmti {
     61 
     62 bool ClassLoaderHelper::AddToClassLoader(art::Thread* self,
     63                                          art::Handle<art::mirror::ClassLoader> loader,
     64                                          const art::DexFile* dex_file) {
     65   art::ScopedObjectAccessUnchecked soa(self);
     66   art::StackHandleScope<3> hs(self);
     67   if (art::ClassLinker::IsBootClassLoader(soa, loader.Get())) {
     68     art::Runtime::Current()->GetClassLinker()->AppendToBootClassPath(self, *dex_file);
     69     return true;
     70   }
     71   art::Handle<art::mirror::Object> java_dex_file_obj(
     72       hs.NewHandle(FindSourceDexFileObject(self, loader)));
     73   if (java_dex_file_obj.IsNull()) {
     74     return false;
     75   }
     76   art::Handle<art::mirror::LongArray> old_cookie(hs.NewHandle(GetDexFileCookie(java_dex_file_obj)));
     77   art::Handle<art::mirror::LongArray> cookie(hs.NewHandle(
     78       AllocateNewDexFileCookie(self, old_cookie, dex_file)));
     79   if (cookie.IsNull()) {
     80     return false;
     81   }
     82   art::ScopedAssertNoThreadSuspension nts("Replacing cookie fields in j.l.DexFile object");
     83   UpdateJavaDexFile(java_dex_file_obj.Get(), cookie.Get());
     84   return true;
     85 }
     86 
     87 void ClassLoaderHelper::UpdateJavaDexFile(art::ObjPtr<art::mirror::Object> java_dex_file,
     88                                           art::ObjPtr<art::mirror::LongArray> new_cookie) {
     89   art::ArtField* internal_cookie_field = java_dex_file->GetClass()->FindDeclaredInstanceField(
     90       "mInternalCookie", "Ljava/lang/Object;");
     91   art::ArtField* cookie_field = java_dex_file->GetClass()->FindDeclaredInstanceField(
     92       "mCookie", "Ljava/lang/Object;");
     93   CHECK(internal_cookie_field != nullptr);
     94   art::ObjPtr<art::mirror::LongArray> orig_internal_cookie(
     95       internal_cookie_field->GetObject(java_dex_file)->AsLongArray());
     96   art::ObjPtr<art::mirror::LongArray> orig_cookie(
     97       cookie_field->GetObject(java_dex_file)->AsLongArray());
     98   internal_cookie_field->SetObject<false>(java_dex_file, new_cookie);
     99   if (!orig_cookie.IsNull()) {
    100     cookie_field->SetObject<false>(java_dex_file, new_cookie);
    101   }
    102 }
    103 
    104 art::ObjPtr<art::mirror::LongArray> ClassLoaderHelper::GetDexFileCookie(
    105     art::Handle<art::mirror::Object> java_dex_file_obj) {
    106   // mCookie is nulled out if the DexFile has been closed but mInternalCookie sticks around until
    107   // the object is finalized. Since they always point to the same array if mCookie is not null we
    108   // just use the mInternalCookie field. We will update one or both of these fields later.
    109   art::ArtField* internal_cookie_field = java_dex_file_obj->GetClass()->FindDeclaredInstanceField(
    110       "mInternalCookie", "Ljava/lang/Object;");
    111   // TODO Add check that mCookie is either null or same as mInternalCookie
    112   CHECK(internal_cookie_field != nullptr);
    113   return internal_cookie_field->GetObject(java_dex_file_obj.Get())->AsLongArray();
    114 }
    115 
    116 art::ObjPtr<art::mirror::LongArray> ClassLoaderHelper::AllocateNewDexFileCookie(
    117     art::Thread* self,
    118     art::Handle<art::mirror::LongArray> cookie,
    119     const art::DexFile* dex_file) {
    120   art::StackHandleScope<1> hs(self);
    121   CHECK(cookie != nullptr);
    122   CHECK_GE(cookie->GetLength(), 1);
    123   art::Handle<art::mirror::LongArray> new_cookie(
    124       hs.NewHandle(art::mirror::LongArray::Alloc(self, cookie->GetLength() + 1)));
    125   if (new_cookie == nullptr) {
    126     self->AssertPendingOOMException();
    127     return nullptr;
    128   }
    129   // Copy the oat-dex field at the start.
    130   new_cookie->SetWithoutChecks<false>(0, cookie->GetWithoutChecks(0));
    131   // This must match the casts in runtime/native/dalvik_system_DexFile.cc:ConvertDexFilesToJavaArray
    132   new_cookie->SetWithoutChecks<false>(
    133       1, static_cast<int64_t>(reinterpret_cast<uintptr_t>(dex_file)));
    134   new_cookie->Memcpy(2, cookie.Get(), 1, cookie->GetLength() - 1);
    135   return new_cookie.Get();
    136 }
    137 
    138 // TODO This should return the actual source java.lang.DexFile object for the klass being loaded.
    139 art::ObjPtr<art::mirror::Object> ClassLoaderHelper::FindSourceDexFileObject(
    140     art::Thread* self, art::Handle<art::mirror::ClassLoader> loader) {
    141   const char* dex_path_list_element_array_name = "[Ldalvik/system/DexPathList$Element;";
    142   const char* dex_path_list_element_name = "Ldalvik/system/DexPathList$Element;";
    143   const char* dex_file_name = "Ldalvik/system/DexFile;";
    144   const char* dex_path_list_name = "Ldalvik/system/DexPathList;";
    145   const char* dex_class_loader_name = "Ldalvik/system/BaseDexClassLoader;";
    146 
    147   CHECK(!self->IsExceptionPending());
    148   art::StackHandleScope<5> hs(self);
    149   art::ClassLinker* class_linker = art::Runtime::Current()->GetClassLinker();
    150 
    151   art::Handle<art::mirror::ClassLoader> null_loader(hs.NewHandle<art::mirror::ClassLoader>(
    152       nullptr));
    153   art::Handle<art::mirror::Class> base_dex_loader_class(hs.NewHandle(class_linker->FindClass(
    154       self, dex_class_loader_name, null_loader)));
    155 
    156   // Get all the ArtFields so we can look in the BaseDexClassLoader
    157   art::ArtField* path_list_field = base_dex_loader_class->FindDeclaredInstanceField(
    158       "pathList", dex_path_list_name);
    159   CHECK(path_list_field != nullptr);
    160 
    161   art::ArtField* dex_path_list_element_field =
    162       class_linker->FindClass(self, dex_path_list_name, null_loader)
    163         ->FindDeclaredInstanceField("dexElements", dex_path_list_element_array_name);
    164   CHECK(dex_path_list_element_field != nullptr);
    165 
    166   art::ArtField* element_dex_file_field =
    167       class_linker->FindClass(self, dex_path_list_element_name, null_loader)
    168         ->FindDeclaredInstanceField("dexFile", dex_file_name);
    169   CHECK(element_dex_file_field != nullptr);
    170 
    171   // Check if loader is a BaseDexClassLoader
    172   art::Handle<art::mirror::Class> loader_class(hs.NewHandle(loader->GetClass()));
    173   // Currently only base_dex_loader is allowed to actually define classes but if this changes in the
    174   // future we should make sure to support all class loader types.
    175   if (!loader_class->IsSubClass(base_dex_loader_class.Get())) {
    176     LOG(ERROR) << "The classloader is not a BaseDexClassLoader which is currently the only "
    177                << "supported class loader type!";
    178     return nullptr;
    179   }
    180   // Start navigating the fields of the loader (now known to be a BaseDexClassLoader derivative)
    181   art::Handle<art::mirror::Object> path_list(
    182       hs.NewHandle(path_list_field->GetObject(loader.Get())));
    183   CHECK(path_list != nullptr);
    184   CHECK(!self->IsExceptionPending());
    185   art::Handle<art::mirror::ObjectArray<art::mirror::Object>> dex_elements_list(hs.NewHandle(
    186       dex_path_list_element_field->GetObject(path_list.Get())->
    187       AsObjectArray<art::mirror::Object>()));
    188   CHECK(!self->IsExceptionPending());
    189   CHECK(dex_elements_list != nullptr);
    190   size_t num_elements = dex_elements_list->GetLength();
    191   // Iterate over the DexPathList$Element to find the right one
    192   for (size_t i = 0; i < num_elements; i++) {
    193     art::ObjPtr<art::mirror::Object> current_element = dex_elements_list->Get(i);
    194     CHECK(!current_element.IsNull());
    195     // TODO It would be cleaner to put the art::DexFile into the dalvik.system.DexFile the class
    196     // comes from but it is more annoying because we would need to find this class. It is not
    197     // necessary for proper function since we just need to be in front of the classes old dex file
    198     // in the path.
    199     art::ObjPtr<art::mirror::Object> first_dex_file(
    200         element_dex_file_field->GetObject(current_element));
    201     if (!first_dex_file.IsNull()) {
    202       return first_dex_file;
    203     }
    204   }
    205   return nullptr;
    206 }
    207 
    208 }  // namespace openjdkjvmti
    209