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 "class_linker.h"
18 #include "dex_file-inl.h"
19 #include "jni_internal.h"
20 #include "nth_caller_visitor.h"
21 #include "mirror/class-inl.h"
22 #include "mirror/class_loader.h"
23 #include "mirror/object-inl.h"
24 #include "scoped_thread_state_change.h"
25 #include "scoped_fast_native_object_access.h"
26 #include "ScopedLocalRef.h"
27 #include "ScopedUtfChars.h"
28 #include "well_known_classes.h"
29 
30 namespace art {
31 
DecodeClass(const ScopedFastNativeObjectAccess & soa,jobject java_class)32 static mirror::Class* DecodeClass(const ScopedFastNativeObjectAccess& soa, jobject java_class)
33     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
34   mirror::Class* c = soa.Decode<mirror::Class*>(java_class);
35   DCHECK(c != NULL);
36   DCHECK(c->IsClass());
37   // TODO: we could EnsureInitialized here, rather than on every reflective get/set or invoke .
38   // For now, we conservatively preserve the old dalvik behavior. A quick "IsInitialized" check
39   // every time probably doesn't make much difference to reflection performance anyway.
40   return c;
41 }
42 
43 // "name" is in "binary name" format, e.g. "dalvik.system.Debug$1".
Class_classForName(JNIEnv * env,jclass,jstring javaName,jboolean initialize,jobject javaLoader)44 static jclass Class_classForName(JNIEnv* env, jclass, jstring javaName, jboolean initialize,
45                                  jobject javaLoader) {
46   ScopedFastNativeObjectAccess soa(env);
47   ScopedUtfChars name(env, javaName);
48   if (name.c_str() == nullptr) {
49     return nullptr;
50   }
51 
52   // We need to validate and convert the name (from x.y.z to x/y/z).  This
53   // is especially handy for array types, since we want to avoid
54   // auto-generating bogus array classes.
55   if (!IsValidBinaryClassName(name.c_str())) {
56     ThrowLocation throw_location = soa.Self()->GetCurrentLocationForThrow();
57     soa.Self()->ThrowNewExceptionF(throw_location, "Ljava/lang/ClassNotFoundException;",
58                                    "Invalid name: %s", name.c_str());
59     return nullptr;
60   }
61 
62   std::string descriptor(DotToDescriptor(name.c_str()));
63   StackHandleScope<2> hs(soa.Self());
64   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(soa.Decode<mirror::ClassLoader*>(javaLoader)));
65   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
66   Handle<mirror::Class> c(
67       hs.NewHandle(class_linker->FindClass(soa.Self(), descriptor.c_str(), class_loader)));
68   if (c.Get() == nullptr) {
69     ScopedLocalRef<jthrowable> cause(env, env->ExceptionOccurred());
70     env->ExceptionClear();
71     jthrowable cnfe = reinterpret_cast<jthrowable>(env->NewObject(WellKnownClasses::java_lang_ClassNotFoundException,
72                                                                   WellKnownClasses::java_lang_ClassNotFoundException_init,
73                                                                   javaName, cause.get()));
74     if (cnfe != nullptr) {
75       // Make sure allocation didn't fail with an OOME.
76       env->Throw(cnfe);
77     }
78     return nullptr;
79   }
80   if (initialize) {
81     class_linker->EnsureInitialized(c, true, true);
82   }
83   return soa.AddLocalReference<jclass>(c.Get());
84 }
85 
Class_getNameNative(JNIEnv * env,jobject javaThis)86 static jstring Class_getNameNative(JNIEnv* env, jobject javaThis) {
87   ScopedFastNativeObjectAccess soa(env);
88   StackHandleScope<1> hs(soa.Self());
89   mirror::Class* const c = DecodeClass(soa, javaThis);
90   return soa.AddLocalReference<jstring>(mirror::Class::ComputeName(hs.NewHandle(c)));
91 }
92 
Class_getProxyInterfaces(JNIEnv * env,jobject javaThis)93 static jobjectArray Class_getProxyInterfaces(JNIEnv* env, jobject javaThis) {
94   ScopedFastNativeObjectAccess soa(env);
95   mirror::Class* c = DecodeClass(soa, javaThis);
96   return soa.AddLocalReference<jobjectArray>(c->GetInterfaces()->Clone(soa.Self()));
97 }
98 
99 static JNINativeMethod gMethods[] = {
100   NATIVE_METHOD(Class, classForName, "!(Ljava/lang/String;ZLjava/lang/ClassLoader;)Ljava/lang/Class;"),
101   NATIVE_METHOD(Class, getNameNative, "!()Ljava/lang/String;"),
102   NATIVE_METHOD(Class, getProxyInterfaces, "!()[Ljava/lang/Class;"),
103 };
104 
register_java_lang_Class(JNIEnv * env)105 void register_java_lang_Class(JNIEnv* env) {
106   REGISTER_NATIVE_METHODS("java/lang/Class");
107 }
108 
109 }  // namespace art
110