1/*
2 * Copyright (C) 2008 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#include "java_lang_VMClassLoader.h"
18
19#include "class_linker.h"
20#include "dex/descriptors_names.h"
21#include "dex/dex_file_loader.h"
22#include "jni_internal.h"
23#include "mirror/class_loader.h"
24#include "mirror/object-inl.h"
25#include "native_util.h"
26#include "nativehelper/jni_macros.h"
27#include "nativehelper/scoped_local_ref.h"
28#include "nativehelper/scoped_utf_chars.h"
29#include "obj_ptr.h"
30#include "scoped_fast_native_object_access-inl.h"
31#include "well_known_classes.h"
32#include "zip_archive.h"
33
34namespace art {
35
36// A class so we can be friends with ClassLinker and access internal methods.
37class VMClassLoader {
38 public:
39  static mirror::Class* LookupClass(ClassLinker* cl,
40                                    Thread* self,
41                                    const char* descriptor,
42                                    size_t hash,
43                                    ObjPtr<mirror::ClassLoader> class_loader)
44      REQUIRES(!Locks::classlinker_classes_lock_)
45      REQUIRES_SHARED(Locks::mutator_lock_) {
46    return cl->LookupClass(self, descriptor, hash, class_loader);
47  }
48
49  static ObjPtr<mirror::Class> FindClassInPathClassLoader(ClassLinker* cl,
50                                                          ScopedObjectAccessAlreadyRunnable& soa,
51                                                          Thread* self,
52                                                          const char* descriptor,
53                                                          size_t hash,
54                                                          Handle<mirror::ClassLoader> class_loader)
55      REQUIRES_SHARED(Locks::mutator_lock_) {
56    ObjPtr<mirror::Class> result;
57    if (cl->FindClassInBaseDexClassLoader(soa, self, descriptor, hash, class_loader, &result)) {
58      return result;
59    }
60    return nullptr;
61  }
62};
63
64static jclass VMClassLoader_findLoadedClass(JNIEnv* env, jclass, jobject javaLoader,
65                                            jstring javaName) {
66  ScopedFastNativeObjectAccess soa(env);
67  ObjPtr<mirror::ClassLoader> loader = soa.Decode<mirror::ClassLoader>(javaLoader);
68  ScopedUtfChars name(env, javaName);
69  if (name.c_str() == nullptr) {
70    return nullptr;
71  }
72  ClassLinker* cl = Runtime::Current()->GetClassLinker();
73
74  // Compute hash once.
75  std::string descriptor(DotToDescriptor(name.c_str()));
76  const size_t descriptor_hash = ComputeModifiedUtf8Hash(descriptor.c_str());
77
78  ObjPtr<mirror::Class> c = VMClassLoader::LookupClass(cl,
79                                                       soa.Self(),
80                                                       descriptor.c_str(),
81                                                       descriptor_hash,
82                                                       loader);
83  if (c != nullptr && c->IsResolved()) {
84    return soa.AddLocalReference<jclass>(c);
85  }
86  // If class is erroneous, throw the earlier failure, wrapped in certain cases. See b/28787733.
87  if (c != nullptr && c->IsErroneous()) {
88    cl->ThrowEarlierClassFailure(c.Ptr());
89    Thread* self = soa.Self();
90    ObjPtr<mirror::Class> iae_class =
91        self->DecodeJObject(WellKnownClasses::java_lang_IllegalAccessError)->AsClass();
92    ObjPtr<mirror::Class> ncdfe_class =
93        self->DecodeJObject(WellKnownClasses::java_lang_NoClassDefFoundError)->AsClass();
94    ObjPtr<mirror::Class> exception = self->GetException()->GetClass();
95    if (exception == iae_class || exception == ncdfe_class) {
96      self->ThrowNewWrappedException("Ljava/lang/ClassNotFoundException;",
97                                     c->PrettyDescriptor().c_str());
98    }
99    return nullptr;
100  }
101
102  // Hard-coded performance optimization: We know that all failed libcore calls to findLoadedClass
103  //                                      are followed by a call to the the classloader to actually
104  //                                      load the class.
105  if (loader != nullptr) {
106    // Try the common case.
107    StackHandleScope<1> hs(soa.Self());
108    c = VMClassLoader::FindClassInPathClassLoader(cl,
109                                                  soa,
110                                                  soa.Self(),
111                                                  descriptor.c_str(),
112                                                  descriptor_hash,
113                                                  hs.NewHandle(loader));
114    if (c != nullptr) {
115      return soa.AddLocalReference<jclass>(c);
116    }
117  }
118
119  // The class wasn't loaded, yet, and our fast-path did not apply (e.g., we didn't understand the
120  // classloader chain).
121  return nullptr;
122}
123
124/*
125 * Returns an array of entries from the boot classpath that could contain resources.
126 */
127static jobjectArray VMClassLoader_getBootClassPathEntries(JNIEnv* env, jclass) {
128  const std::vector<const DexFile*>& path =
129      Runtime::Current()->GetClassLinker()->GetBootClassPath();
130  jobjectArray array =
131      env->NewObjectArray(path.size(), WellKnownClasses::java_lang_String, nullptr);
132  if (array == nullptr) {
133    DCHECK(env->ExceptionCheck());
134    return nullptr;
135  }
136  for (size_t i = 0; i < path.size(); ++i) {
137    const DexFile* dex_file = path[i];
138
139    // For multidex locations, e.g., x.jar!classes2.dex, we want to look into x.jar.
140    const std::string location(DexFileLoader::GetBaseLocation(dex_file->GetLocation()));
141
142    ScopedLocalRef<jstring> javaPath(env, env->NewStringUTF(location.c_str()));
143    if (javaPath.get() == nullptr) {
144      DCHECK(env->ExceptionCheck());
145      return nullptr;
146    }
147    env->SetObjectArrayElement(array, i, javaPath.get());
148  }
149  return array;
150}
151
152static JNINativeMethod gMethods[] = {
153  FAST_NATIVE_METHOD(VMClassLoader, findLoadedClass, "(Ljava/lang/ClassLoader;Ljava/lang/String;)Ljava/lang/Class;"),
154  NATIVE_METHOD(VMClassLoader, getBootClassPathEntries, "()[Ljava/lang/String;"),
155};
156
157void register_java_lang_VMClassLoader(JNIEnv* env) {
158  REGISTER_NATIVE_METHODS("java/lang/VMClassLoader");
159}
160
161}  // namespace art
162