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 "classfile/sharedClassUtil.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 "trace/traceMacros.hpp"
  39 
  40 // called during initial loading of a shared class
  41 InstanceKlass* KlassFactory::check_shared_class_file_load_hook(
  42                                           InstanceKlass* ik,
  43                                           Symbol* class_name,
  44                                           Handle class_loader,
  45                                           Handle protection_domain, TRAPS) {
  46 #if INCLUDE_CDS && INCLUDE_JVMTI
  47   assert(ik != NULL, "sanity");
  48   assert(ik->is_shared(), "expecting a shared class");
  49 
  50   if (JvmtiExport::should_post_class_file_load_hook()) {
  51     assert(THREAD->is_Java_thread(), "must be JavaThread");
  52 
  53     // Post the CFLH
  54     JvmtiCachedClassFileData* cached_class_file = NULL;
  55     JvmtiCachedClassFileData* archived_class_data = ik->get_archived_class_data();
  56     assert(archived_class_data != NULL, "shared class has no archived class data");
  57     unsigned char* ptr =
  58         VM_RedefineClasses::get_cached_class_file_bytes(archived_class_data);
  59     unsigned char* end_ptr =
  60         ptr + VM_RedefineClasses::get_cached_class_file_len(archived_class_data);
  61     unsigned char* old_ptr = ptr;
  62     JvmtiExport::post_class_file_load_hook(class_name,
  63                                            class_loader,
  64                                            protection_domain,
  65                                            &ptr,
  66                                            &end_ptr,
  67                                            &cached_class_file);
  68     if (old_ptr != ptr) {
  69       // JVMTI agent has modified class file data.
  70       // Set new class file stream using JVMTI agent modified class file data.
  71       ClassLoaderData* loader_data =
  72         ClassLoaderData::class_loader_data(class_loader());
  73       int path_index = ik->shared_classpath_index();
  74       const char* pathname;
  75       if (path_index < 0) {
  76         // shared classes loaded by user defined class loader
  77         // do not have shared_classpath_index
  78         ModuleEntry* mod_entry = ik->module();
  79         if (mod_entry != NULL && (mod_entry->location() != NULL)) {
  80           ResourceMark rm;
  81           pathname = (const char*)(mod_entry->location()->as_C_string());
  82         } else {
  83           pathname = "";
  84         }
  85       } else {
  86         SharedClassPathEntry* ent =
  87           (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
  88         pathname = ent == NULL ? NULL : ent->name();
  89       }
  90       ClassFileStream* stream = new ClassFileStream(ptr,
  91                                                     end_ptr - ptr,
  92                                                     pathname,
  93                                                     ClassFileStream::verify);
  94       ClassFileParser parser(stream,
  95                              class_name,
  96                              loader_data,
  97                              protection_domain,
  98                              NULL,
  99                              NULL,
 100                              ClassFileParser::BROADCAST, // publicity level
 101                              CHECK_NULL);
 102       InstanceKlass* new_ik = parser.create_instance_klass(true /* changed_by_loadhook */,
 103                                                            CHECK_NULL);
 104       if (cached_class_file != NULL) {
 105         new_ik->set_cached_class_file(cached_class_file);
 106       }
 107 
 108       if (class_loader.is_null()) {
 109         ResourceMark rm;
 110         ClassLoader::add_package(class_name->as_C_string(), path_index, THREAD);
 111       }
 112 
 113       return new_ik;
 114     }
 115   }
 116 #endif
 117 
 118   return NULL;
 119 }
 120 
 121 
 122 static ClassFileStream* check_class_file_load_hook(ClassFileStream* stream,
 123                                                    Symbol* name,
 124                                                    ClassLoaderData* loader_data,
 125                                                    Handle protection_domain,
 126                                                    JvmtiCachedClassFileData** cached_class_file,
 127                                                    TRAPS) {
 128 
 129   assert(stream != NULL, "invariant");
 130 
 131   if (JvmtiExport::should_post_class_file_load_hook()) {
 132     assert(THREAD->is_Java_thread(), "must be a JavaThread");
 133     const JavaThread* jt = (JavaThread*)THREAD;
 134 
 135     Handle class_loader(THREAD, loader_data->class_loader());
 136 
 137     // Get the cached class file bytes (if any) from the class that
 138     // is being redefined or retransformed. We use jvmti_thread_state()
 139     // instead of JvmtiThreadState::state_for(jt) so we don't allocate
 140     // a JvmtiThreadState any earlier than necessary. This will help
 141     // avoid the bug described by 7126851.
 142 
 143     JvmtiThreadState* state = jt->jvmti_thread_state();
 144 
 145     if (state != NULL) {
 146       Klass* k = state->get_class_being_redefined();
 147 
 148       if (k != NULL) {
 149         InstanceKlass* class_being_redefined = InstanceKlass::cast(k);
 150         *cached_class_file = class_being_redefined->get_cached_class_file();
 151       }
 152     }
 153 
 154     unsigned char* ptr = const_cast<unsigned char*>(stream->buffer());
 155     unsigned char* end_ptr = ptr + stream->length();
 156 
 157     JvmtiExport::post_class_file_load_hook(name,
 158                                            class_loader,
 159                                            protection_domain,
 160                                            &ptr,
 161                                            &end_ptr,
 162                                            cached_class_file);
 163 
 164     if (ptr != stream->buffer()) {
 165       // JVMTI agent has modified class file data.
 166       // Set new class file stream using JVMTI agent modified class file data.
 167       stream = new ClassFileStream(ptr,
 168                                    end_ptr - ptr,
 169                                    stream->source(),
 170                                    stream->need_verify());
 171     }
 172   }
 173 
 174   return stream;
 175 }
 176 
 177 
 178 InstanceKlass* KlassFactory::create_from_stream(ClassFileStream* stream,
 179                                                 Symbol* name,
 180                                                 ClassLoaderData* loader_data,
 181                                                 Handle protection_domain,
 182                                                 const InstanceKlass* host_klass,
 183                                                 GrowableArray<Handle>* cp_patches,
 184                                                 TRAPS) {
 185   assert(stream != NULL, "invariant");
 186   assert(loader_data != NULL, "invariant");
 187   assert(THREAD->is_Java_thread(), "must be a JavaThread");
 188 
 189   ResourceMark rm;
 190   HandleMark hm;
 191 
 192   JvmtiCachedClassFileData* cached_class_file = NULL;
 193 
 194   ClassFileStream* old_stream = stream;
 195 
 196   // increment counter
 197   THREAD->statistic_info().incr_define_class_count();
 198 
 199   // Skip this processing for VM anonymous classes
 200   if (host_klass == NULL) {
 201     stream = check_class_file_load_hook(stream,
 202                                         name,
 203                                         loader_data,
 204                                         protection_domain,
 205                                         &cached_class_file,
 206                                         CHECK_NULL);
 207   }
 208 
 209   ClassFileParser parser(stream,
 210                          name,
 211                          loader_data,
 212                          protection_domain,
 213                          host_klass,
 214                          cp_patches,
 215                          ClassFileParser::BROADCAST, // publicity level
 216                          CHECK_NULL);
 217 
 218   InstanceKlass* result = parser.create_instance_klass(old_stream != stream, CHECK_NULL);
 219   assert(result == parser.create_instance_klass(old_stream != stream, THREAD), "invariant");
 220 
 221   if (result == NULL) {
 222     return NULL;
 223   }
 224 
 225   if (cached_class_file != NULL) {
 226     // JVMTI: we have an InstanceKlass now, tell it about the cached bytes
 227     result->set_cached_class_file(cached_class_file);
 228   }
 229 
 230   if (result->should_store_fingerprint()) {
 231     result->store_fingerprint(stream->compute_fingerprint());
 232   }
 233 
 234   TRACE_KLASS_CREATION(result, parser, THREAD);
 235 
 236 #if INCLUDE_CDS
 237   if (DumpSharedSpaces) {
 238     ClassLoader::record_result(result, stream, THREAD);
 239 #if INCLUDE_JVMTI
 240     assert(cached_class_file == NULL, "Sanity");
 241     // Archive the class stream data into the optional data section
 242     JvmtiCachedClassFileData *p;
 243     int len;
 244     const unsigned char *bytes;
 245     // event based tracing might set cached_class_file
 246     if ((bytes = result->get_cached_class_file_bytes()) != NULL) {
 247       len = result->get_cached_class_file_len();
 248     } else {
 249       len = stream->length();
 250       bytes = stream->buffer();
 251     }
 252     p = (JvmtiCachedClassFileData*)os::malloc(offset_of(JvmtiCachedClassFileData, data) + len, mtInternal);
 253     p->length = len;
 254     memcpy(p->data, bytes, len);
 255     result->set_archived_class_data(p);
 256 #endif // INCLUDE_JVMTI
 257   }
 258 #endif // INCLUDE_CDS
 259 
 260   return result;
 261 }