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