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      1 /* Copyright (C) 2016 The Android Open Source Project
      2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
      3  *
      4  * This file implements interfaces from the file jvmti.h. This implementation
      5  * is licensed under the same terms as the file jvmti.h.  The
      6  * copyright and license information for the file jvmti.h follows.
      7  *
      8  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
      9  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     10  *
     11  * This code is free software; you can redistribute it and/or modify it
     12  * under the terms of the GNU General Public License version 2 only, as
     13  * published by the Free Software Foundation.  Oracle designates this
     14  * particular file as subject to the "Classpath" exception as provided
     15  * by Oracle in the LICENSE file that accompanied this code.
     16  *
     17  * This code is distributed in the hope that it will be useful, but WITHOUT
     18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     20  * version 2 for more details (a copy is included in the LICENSE file that
     21  * accompanied this code).
     22  *
     23  * You should have received a copy of the GNU General Public License version
     24  * 2 along with this work; if not, write to the Free Software Foundation,
     25  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     26  *
     27  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     28  * or visit www.oracle.com if you need additional information or have any
     29  * questions.
     30  */
     31 
     32 #include "ti_field.h"
     33 
     34 #include "art_jvmti.h"
     35 #include "art_field-inl.h"
     36 #include "base/enums.h"
     37 #include "dex_file_annotations.h"
     38 #include "jni_internal.h"
     39 #include "mirror/object_array-inl.h"
     40 #include "modifiers.h"
     41 #include "scoped_thread_state_change-inl.h"
     42 #include "thread-inl.h"
     43 
     44 namespace openjdkjvmti {
     45 
     46 // Note: For all these functions, we could do a check that the field actually belongs to the given
     47 //       class. But the spec seems to assume a certain encoding of the field ID, and so doesn't
     48 //       specify any errors.
     49 
     50 jvmtiError FieldUtil::GetFieldName(jvmtiEnv* env,
     51                                    jclass klass,
     52                                    jfieldID field,
     53                                    char** name_ptr,
     54                                    char** signature_ptr,
     55                                    char** generic_ptr) {
     56   if (klass == nullptr) {
     57     return ERR(INVALID_CLASS);
     58   }
     59   if (field == nullptr) {
     60     return ERR(INVALID_FIELDID);
     61   }
     62 
     63   art::ScopedObjectAccess soa(art::Thread::Current());
     64   art::ArtField* art_field = art::jni::DecodeArtField(field);
     65 
     66   JvmtiUniquePtr<char[]> name_copy;
     67   if (name_ptr != nullptr) {
     68     const char* field_name = art_field->GetName();
     69     if (field_name == nullptr) {
     70       field_name = "<error>";
     71     }
     72     jvmtiError ret;
     73     name_copy = CopyString(env, field_name, &ret);
     74     if (name_copy == nullptr) {
     75       return ret;
     76     }
     77     *name_ptr = name_copy.get();
     78   }
     79 
     80   JvmtiUniquePtr<char[]> signature_copy;
     81   if (signature_ptr != nullptr) {
     82     const char* sig = art_field->GetTypeDescriptor();
     83     jvmtiError ret;
     84     signature_copy = CopyString(env, sig, &ret);
     85     if (signature_copy == nullptr) {
     86       return ret;
     87     }
     88     *signature_ptr = signature_copy.get();
     89   }
     90 
     91   if (generic_ptr != nullptr) {
     92     *generic_ptr = nullptr;
     93     if (!art_field->GetDeclaringClass()->IsProxyClass()) {
     94       art::mirror::ObjectArray<art::mirror::String>* str_array =
     95           art::annotations::GetSignatureAnnotationForField(art_field);
     96       if (str_array != nullptr) {
     97         std::ostringstream oss;
     98         for (int32_t i = 0; i != str_array->GetLength(); ++i) {
     99           oss << str_array->Get(i)->ToModifiedUtf8();
    100         }
    101         std::string output_string = oss.str();
    102         jvmtiError ret;
    103         JvmtiUniquePtr<char[]> copy = CopyString(env, output_string.c_str(), &ret);
    104         if (copy == nullptr) {
    105           return ret;
    106         }
    107         *generic_ptr = copy.release();
    108       } else if (soa.Self()->IsExceptionPending()) {
    109         // TODO: Should we report an error here?
    110         soa.Self()->ClearException();
    111       }
    112     }
    113   }
    114 
    115   // Everything is fine, release the buffers.
    116   name_copy.release();
    117   signature_copy.release();
    118 
    119   return ERR(NONE);
    120 }
    121 
    122 jvmtiError FieldUtil::GetFieldDeclaringClass(jvmtiEnv* env ATTRIBUTE_UNUSED,
    123                                              jclass klass,
    124                                              jfieldID field,
    125                                              jclass* declaring_class_ptr) {
    126   if (klass == nullptr) {
    127     return ERR(INVALID_CLASS);
    128   }
    129   if (field == nullptr) {
    130     return ERR(INVALID_FIELDID);
    131   }
    132   if (declaring_class_ptr == nullptr) {
    133     return ERR(NULL_POINTER);
    134   }
    135 
    136   art::ScopedObjectAccess soa(art::Thread::Current());
    137   art::ArtField* art_field = art::jni::DecodeArtField(field);
    138   art::ObjPtr<art::mirror::Class> field_klass = art_field->GetDeclaringClass();
    139 
    140   *declaring_class_ptr = soa.AddLocalReference<jclass>(field_klass);
    141 
    142   return ERR(NONE);
    143 }
    144 
    145 jvmtiError FieldUtil::GetFieldModifiers(jvmtiEnv* env ATTRIBUTE_UNUSED,
    146                                         jclass klass,
    147                                         jfieldID field,
    148                                         jint* modifiers_ptr) {
    149   if (klass == nullptr) {
    150     return ERR(INVALID_CLASS);
    151   }
    152   if (field == nullptr) {
    153     return ERR(INVALID_FIELDID);
    154   }
    155   if (modifiers_ptr == nullptr) {
    156     return ERR(NULL_POINTER);
    157   }
    158 
    159   art::ScopedObjectAccess soa(art::Thread::Current());
    160   art::ArtField* art_field = art::jni::DecodeArtField(field);
    161   // Note: Keep this code in sync with Field.getModifiers.
    162   uint32_t modifiers = art_field->GetAccessFlags() & 0xFFFF;
    163 
    164   *modifiers_ptr = modifiers;
    165   return ERR(NONE);
    166 }
    167 
    168 jvmtiError FieldUtil::IsFieldSynthetic(jvmtiEnv* env ATTRIBUTE_UNUSED,
    169                                        jclass klass,
    170                                        jfieldID field,
    171                                        jboolean* is_synthetic_ptr) {
    172   if (klass == nullptr) {
    173     return ERR(INVALID_CLASS);
    174   }
    175   if (field == nullptr) {
    176     return ERR(INVALID_FIELDID);
    177   }
    178   if (is_synthetic_ptr == nullptr) {
    179     return ERR(NULL_POINTER);
    180   }
    181 
    182   art::ScopedObjectAccess soa(art::Thread::Current());
    183   art::ArtField* art_field = art::jni::DecodeArtField(field);
    184   uint32_t modifiers = art_field->GetAccessFlags();
    185 
    186   *is_synthetic_ptr = ((modifiers & art::kAccSynthetic) != 0) ? JNI_TRUE : JNI_FALSE;
    187   return ERR(NONE);
    188 }
    189 
    190 }  // namespace openjdkjvmti
    191