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