1 /*
   2 * Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
   3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4 *
   5 * This code is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License version 2 only, as
   7 * published by the Free Software Foundation.
   8 *
   9 * This code is distributed in the hope that it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 * version 2 for more details (a copy is included in the LICENSE file that
  13 * accompanied this code).
  14 *
  15 * You should have received a copy of the GNU General Public License version
  16 * 2 along with this work; if not, write to the Free Software Foundation,
  17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18 *
  19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20 * or visit www.oracle.com if you need additional information or have any
  21 * questions.
  22 *
  23 */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/classFileParser.hpp"
  27 #include "classfile/classFileStream.hpp"
  28 #include "classfile/classLoader.hpp"
  29 #include "classfile/classLoaderData.hpp"
  30 #include "classfile/classLoaderData.inline.hpp"
  31 #include "classfile/klassFactory.hpp"
  32 #include "memory/filemap.hpp"
  33 #include "memory/metaspaceShared.hpp"
  34 #include "memory/resourceArea.hpp"
  35 #include "prims/jvmtiEnvBase.hpp"
  36 #include "prims/jvmtiRedefineClasses.hpp"
  37 #include "runtime/handles.inline.hpp"
  38 #include "utilities/macros.hpp"
  39 #if INCLUDE_JFR
  40 #include "jfr/support/jfrKlassExtension.hpp"
  41 #endif
  42 
  43 
  44 // called during initial loading of a shared class
  45 InstanceKlass* KlassFactory::check_shared_class_file_load_hook(
  46                                           InstanceKlass* ik,
  47                                           Symbol* class_name,
  48                                           Handle class_loader,
  49                                           Handle protection_domain, TRAPS) {
  50 #if INCLUDE_CDS && INCLUDE_JVMTI
  51   assert(ik != NULL, "sanity");
  52   assert(ik->is_shared(), "expecting a shared class");
  53 
  54   if (JvmtiExport::should_post_class_file_load_hook()) {
  55     assert(THREAD->is_Java_thread(), "must be JavaThread");
  56 
  57     // Post the CFLH
  58     JvmtiCachedClassFileData* cached_class_file = NULL;
  59     JvmtiCachedClassFileData* archived_class_data = ik->get_archived_class_data();
  60     assert(archived_class_data != NULL, "shared class has no archived class data");
  61     unsigned char* ptr =
  62         VM_RedefineClasses::get_cached_class_file_bytes(archived_class_data);
  63     unsigned char* end_ptr =
  64         ptr + VM_RedefineClasses::get_cached_class_file_len(archived_class_data);
  65     unsigned char* old_ptr = ptr;
  66     JvmtiExport::post_class_file_load_hook(class_name,
  67                                            class_loader,
  68                                            protection_domain,
  69                                            &ptr,
  70                                            &end_ptr,
  71                                            &cached_class_file);
  72     if (old_ptr != ptr) {
  73       // JVMTI agent has modified class file data.
  74       // Set new class file stream using JVMTI agent modified class file data.
  75       ClassLoaderData* loader_data =
  76         ClassLoaderData::class_loader_data(class_loader());
  77       int path_index = ik->shared_classpath_index();
  78       const char* pathname;
  79       if (path_index < 0) {
  80         // shared classes loaded by user defined class loader
  81         // do not have shared_classpath_index
  82         ModuleEntry* mod_entry = ik->module();
  83         if (mod_entry != NULL && (mod_entry->location() != NULL)) {
  84           ResourceMark rm;
  85           pathname = (const char*)(mod_entry->location()->as_C_string());
  86         } else {
  87           pathname = "";
  88         }
  89       } else {
  90         SharedClassPathEntry* ent =
  91           (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
  92         pathname = ent == NULL ? NULL : ent->name();
  93       }
  94       ClassFileStream* stream = new ClassFileStream(ptr,
  95                                                     end_ptr - ptr,
  96                                                     pathname,
  97                                                     ClassFileStream::verify);
  98       ClassFileParser parser(stream,
  99                              class_name,
 100                              loader_data,
 101                              protection_domain,
 102                              NULL,
 103                              NULL,
 104                              ClassFileParser::BROADCAST, // publicity level
 105                              CHECK_NULL);
 106       InstanceKlass* new_ik = parser.create_instance_klass(true /* changed_by_loadhook */,
 107                                                            CHECK_NULL);
 108       if (cached_class_file != NULL) {
 109         new_ik->set_cached_class_file(cached_class_file);
 110       }
 111 
 112       if (class_loader.is_null()) {
 113         ResourceMark rm;
 114         ClassLoader::add_package(class_name->as_C_string(), path_index, THREAD);
 115       }
 116 
 117       return new_ik;
 118     }
 119   }
 120 #endif
 121 
 122   return NULL;
 123 }
 124 
 125 
 126 static ClassFileStream* check_class_file_load_hook(ClassFileStream* stream,
 127                                                    Symbol* name,
 128                                                    ClassLoaderData* loader_data,
 129                                                    Handle protection_domain,
 130                                                    JvmtiCachedClassFileData** cached_class_file,
 131                                                    TRAPS) {
 132 
 133   assert(stream != NULL, "invariant");
 134 
 135   if (JvmtiExport::should_post_class_file_load_hook()) {
 136     assert(THREAD->is_Java_thread(), "must be a JavaThread");
 137     const JavaThread* jt = (JavaThread*)THREAD;
 138 
 139     Handle class_loader(THREAD, loader_data->class_loader());
 140 
 141     // Get the cached class file bytes (if any) from the class that
 142     // is being redefined or retransformed. We use jvmti_thread_state()
 143     // instead of JvmtiThreadState::state_for(jt) so we don't allocate
 144     // a JvmtiThreadState any earlier than necessary. This will help
 145     // avoid the bug described by 7126851.
 146 
 147     JvmtiThreadState* state = jt->jvmti_thread_state();
 148 
 149     if (state != NULL) {
 150       Klass* k = state->get_class_being_redefined();
 151 
 152       if (k != NULL) {
 153         InstanceKlass* class_being_redefined = InstanceKlass::cast(k);
 154         *cached_class_file = class_being_redefined->get_cached_class_file();
 155       }
 156     }
 157 
 158     unsigned char* ptr = const_cast<unsigned char*>(stream->buffer());
 159     unsigned char* end_ptr = ptr + stream->length();
 160 
 161     JvmtiExport::post_class_file_load_hook(name,
 162                                            class_loader,
 163                                            protection_domain,
 164                                            &ptr,
 165                                            &end_ptr,
 166                                            cached_class_file);
 167 
 168     if (ptr != stream->buffer()) {
 169       // JVMTI agent has modified class file data.
 170       // Set new class file stream using JVMTI agent modified class file data.
 171       stream = new ClassFileStream(ptr,
 172                                    end_ptr - ptr,
 173                                    stream->source(),
 174                                    stream->need_verify());
 175     }
 176   }
 177 
 178   return stream;
 179 }
 180 
 181 
 182 InstanceKlass* KlassFactory::create_from_stream(ClassFileStream* stream,
 183                                                 Symbol* name,
 184                                                 ClassLoaderData* loader_data,
 185                                                 Handle protection_domain,
 186                                                 const InstanceKlass* host_klass,
 187                                                 GrowableArray<Handle>* cp_patches,
 188                                                 TRAPS) {
 189   assert(stream != NULL, "invariant");
 190   assert(loader_data != NULL, "invariant");
 191   assert(THREAD->is_Java_thread(), "must be a JavaThread");
 192 
 193   ResourceMark rm;
 194   HandleMark hm;
 195 
 196   JvmtiCachedClassFileData* cached_class_file = NULL;
 197 
 198   ClassFileStream* old_stream = stream;
 199 
 200   // Skip this processing for VM anonymous classes
 201   if (host_klass == NULL) {
 202     stream = check_class_file_load_hook(stream,
 203                                         name,
 204                                         loader_data,
 205                                         protection_domain,
 206                                         &cached_class_file,
 207                                         CHECK_NULL);
 208   }
 209 
 210   ClassFileParser parser(stream,
 211                          name,
 212                          loader_data,
 213                          protection_domain,
 214                          host_klass,
 215                          cp_patches,
 216                          ClassFileParser::BROADCAST, // publicity level
 217                          CHECK_NULL);
 218 
 219   InstanceKlass* result = parser.create_instance_klass(old_stream != stream, CHECK_NULL);
 220   assert(result == parser.create_instance_klass(old_stream != stream, THREAD), "invariant");
 221 
 222   if (result == NULL) {
 223     return NULL;
 224   }
 225 
 226   if (cached_class_file != NULL) {
 227     // JVMTI: we have an InstanceKlass now, tell it about the cached bytes
 228     result->set_cached_class_file(cached_class_file);
 229   }
 230 
 231   if (result->should_store_fingerprint()) {
 232     result->store_fingerprint(stream->compute_fingerprint());
 233   }
 234 
 235   JFR_ONLY(ON_KLASS_CREATION(result, parser, THREAD);)
 236 
 237 #if INCLUDE_CDS
 238   if (DumpSharedSpaces) {
 239     ClassLoader::record_result(result, stream, THREAD);
 240 #if INCLUDE_JVMTI
 241     assert(cached_class_file == NULL, "Sanity");
 242     // Archive the class stream data into the optional data section
 243     JvmtiCachedClassFileData *p;
 244     int len;
 245     const unsigned char *bytes;
 246     // event based tracing might set cached_class_file
 247     if ((bytes = result->get_cached_class_file_bytes()) != NULL) {
 248       len = result->get_cached_class_file_len();
 249     } else {
 250       len = stream->length();
 251       bytes = stream->buffer();
 252     }
 253     p = (JvmtiCachedClassFileData*)os::malloc(offset_of(JvmtiCachedClassFileData, data) + len, mtInternal);
 254     p->length = len;
 255     memcpy(p->data, bytes, len);
 256     result->set_archived_class_data(p);
 257 #endif // INCLUDE_JVMTI
 258   }
 259 #endif // INCLUDE_CDS
 260 
 261   return result;
 262 }