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
34 namespace art {
35
36 // A class so we can be friends with ClassLinker and access internal methods.
37 class VMClassLoader {
38 public:
LookupClass(ClassLinker * cl,Thread * self,const char * descriptor,size_t hash,ObjPtr<mirror::ClassLoader> class_loader)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
FindClassInPathClassLoader(ClassLinker * cl,ScopedObjectAccessAlreadyRunnable & soa,Thread * self,const char * descriptor,size_t hash,Handle<mirror::ClassLoader> class_loader)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
VMClassLoader_findLoadedClass(JNIEnv * env,jclass,jobject javaLoader,jstring javaName)64 static 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 */
VMClassLoader_getBootClassPathEntries(JNIEnv * env,jclass)127 static 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
152 static 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
register_java_lang_VMClassLoader(JNIEnv * env)157 void register_java_lang_VMClassLoader(JNIEnv* env) {
158 REGISTER_NATIVE_METHODS("java/lang/VMClassLoader");
159 }
160
161 } // namespace art
162