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      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 "scoped_fast_native_object_access.h"
     24 #include "ScopedUtfChars.h"
     25 #include "zip_archive.h"
     26 
     27 namespace art {
     28 
     29 static jclass VMClassLoader_findLoadedClass(JNIEnv* env, jclass, jobject javaLoader,
     30                                             jstring javaName) {
     31   ScopedFastNativeObjectAccess soa(env);
     32   mirror::ClassLoader* loader = soa.Decode<mirror::ClassLoader*>(javaLoader);
     33   ScopedUtfChars name(env, javaName);
     34   if (name.c_str() == nullptr) {
     35     return nullptr;
     36   }
     37   ClassLinker* cl = Runtime::Current()->GetClassLinker();
     38   std::string descriptor(DotToDescriptor(name.c_str()));
     39   const size_t descriptor_hash = ComputeModifiedUtf8Hash(descriptor.c_str());
     40   mirror::Class* c = cl->LookupClass(soa.Self(), descriptor.c_str(), descriptor_hash, loader);
     41   if (c != nullptr && c->IsResolved()) {
     42     return soa.AddLocalReference<jclass>(c);
     43   }
     44   if (loader != nullptr) {
     45     // Try the common case.
     46     StackHandleScope<1> hs(soa.Self());
     47     cl->FindClassInPathClassLoader(soa, soa.Self(), descriptor.c_str(), descriptor_hash,
     48                                    hs.NewHandle(loader), &c);
     49     if (c != nullptr) {
     50       return soa.AddLocalReference<jclass>(c);
     51     }
     52   }
     53   // Class wasn't resolved so it may be erroneous or not yet ready, force the caller to go into
     54   // the regular loadClass code.
     55   return nullptr;
     56 }
     57 
     58 static jint VMClassLoader_getBootClassPathSize(JNIEnv*, jclass) {
     59   return Runtime::Current()->GetClassLinker()->GetBootClassPath().size();
     60 }
     61 
     62 /*
     63  * Returns a string URL for a resource with the specified 'javaName' in
     64  * entry 'index' of the boot class path.
     65  *
     66  * We return a newly-allocated String in the following form:
     67  *
     68  *   jar:file://path!/name
     69  *
     70  * Where "path" is the bootstrap class path entry and "name" is the string
     71  * passed into this method.  "path" needs to be an absolute path (starting
     72  * with '/'); if it's not we'd need to make it absolute as part of forming
     73  * the URL string.
     74  */
     75 static jstring VMClassLoader_getBootClassPathResource(JNIEnv* env, jclass, jstring javaName,
     76                                                       jint index) {
     77   ScopedUtfChars name(env, javaName);
     78   if (name.c_str() == nullptr) {
     79     return nullptr;
     80   }
     81 
     82   const std::vector<const DexFile*>& path =
     83       Runtime::Current()->GetClassLinker()->GetBootClassPath();
     84   if (index < 0 || size_t(index) >= path.size()) {
     85     return nullptr;
     86   }
     87   const DexFile* dex_file = path[index];
     88 
     89   // For multidex locations, e.g., x.jar:classes2.dex, we want to look into x.jar.
     90   const std::string& location(dex_file->GetBaseLocation());
     91 
     92   std::string error_msg;
     93   std::unique_ptr<ZipArchive> zip_archive(ZipArchive::Open(location.c_str(), &error_msg));
     94   if (zip_archive.get() == nullptr) {
     95     LOG(WARNING) << "Failed to open zip archive '" << location << "': " << error_msg;
     96     return nullptr;
     97   }
     98   std::unique_ptr<ZipEntry> zip_entry(zip_archive->Find(name.c_str(), &error_msg));
     99   if (zip_entry.get() == nullptr) {
    100     return nullptr;
    101   }
    102 
    103   std::string url;
    104   StringAppendF(&url, "jar:file://%s!/%s", location.c_str(), name.c_str());
    105   return env->NewStringUTF(url.c_str());
    106 }
    107 
    108 static JNINativeMethod gMethods[] = {
    109   NATIVE_METHOD(VMClassLoader, findLoadedClass, "!(Ljava/lang/ClassLoader;Ljava/lang/String;)Ljava/lang/Class;"),
    110   NATIVE_METHOD(VMClassLoader, getBootClassPathResource, "(Ljava/lang/String;I)Ljava/lang/String;"),
    111   NATIVE_METHOD(VMClassLoader, getBootClassPathSize, "!()I"),
    112 };
    113 
    114 void register_java_lang_VMClassLoader(JNIEnv* env) {
    115   REGISTER_NATIVE_METHODS("java/lang/VMClassLoader");
    116 }
    117 
    118 }  // namespace art
    119