/*

* Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.

* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

*

* This code is free software; you can redistribute it and/or modify it

* under the terms of the GNU General Public License version 2 only, as

* published by the Free Software Foundation.

*

* This code is distributed in the hope that it will be useful, but WITHOUT

* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

* version 2 for more details (a copy is included in the LICENSE file that

* accompanied this code).

*

* You should have received a copy of the GNU General Public License version

* 2 along with this work; if not, write to the Free Software Foundation,

* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

*

* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

* or visit www.oracle.com if you need additional information or have any

* questions.

*

*/

#include "precompiled.hpp"

#include "classfile/classFileParser.hpp"

#include "classfile/classFileStream.hpp"

#include "classfile/classLoader.hpp"

#include "classfile/classLoaderData.hpp"

#include "classfile/classLoaderData.inline.hpp"

#include "classfile/klassFactory.hpp"

#include "memory/filemap.hpp"

#include "memory/metaspaceShared.hpp"

#include "memory/resourceArea.hpp"

#include "prims/jvmtiEnvBase.hpp"

#include "prims/jvmtiRedefineClasses.hpp"

#include "runtime/handles.inline.hpp"

// called during initial loading of a shared class

InstanceKlass* KlassFactory::check_shared_class_file_load_hook(

                                          InstanceKlass* ik,

                                          Symbol* class_name,

                                          Handle class_loader,

                                          Handle protection_domain, TRAPS) {

#if INCLUDE_CDS && INCLUDE_JVMTI

  assert(ik != NULL, "sanity");

  assert(ik->is_shared(), "expecting a shared class");

  if (JvmtiExport::should_post_class_file_load_hook()) {

    assert(THREAD->is_Java_thread(), "must be JavaThread");

    // Post the CFLH

    JvmtiCachedClassFileData* cached_class_file = NULL;

    JvmtiCachedClassFileData* archived_class_data = ik->get_archived_class_data();

    assert(archived_class_data != NULL, "shared class has no archived class data");

    unsigned char* ptr =

        VM_RedefineClasses::get_cached_class_file_bytes(archived_class_data);

    unsigned char* end_ptr =

        ptr + VM_RedefineClasses::get_cached_class_file_len(archived_class_data);

    unsigned char* old_ptr = ptr;

    JvmtiExport::post_class_file_load_hook(class_name,

                                           class_loader,

                                           protection_domain,

                                           &ptr,

                                           &end_ptr,

                                           &cached_class_file);

    if (old_ptr != ptr) {

      // JVMTI agent has modified class file data.

      // Set new class file stream using JVMTI agent modified class file data.

      ClassLoaderData* loader_data =

        ClassLoaderData::class_loader_data(class_loader());

      int path_index = ik->shared_classpath_index();

      const char* pathname;

      if (path_index < 0) {

        // shared classes loaded by user defined class loader

        // do not have shared_classpath_index

        ModuleEntry* mod_entry = ik->module();

        if (mod_entry != NULL && (mod_entry->location() != NULL)) {

          ResourceMark rm;

          pathname = (const char*)(mod_entry->location()->as_C_string());

        } else {

          pathname = "";

        }

      } else {

        SharedClassPathEntry* ent =

          (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);

        pathname = ent == NULL ? NULL : ent->name();

      }

      ClassFileStream* stream = new ClassFileStream(ptr,

                                                    end_ptr - ptr,

                                                    pathname,

                                                    ClassFileStream::verify);

      ClassFileParser parser(stream,

                             class_name,

                             loader_data,

                             protection_domain,

                             NULL,

                             NULL,

                             ClassFileParser::BROADCAST, // publicity level

                             CHECK_NULL);

      InstanceKlass* new_ik = parser.create_instance_klass(true /* changed_by_loadhook */,

                                                           CHECK_NULL);

      if (cached_class_file != NULL) {

        new_ik->set_cached_class_file(cached_class_file);

      }

      if (class_loader.is_null()) {

        ResourceMark rm;

        ClassLoader::add_package(class_name->as_C_string(), path_index, THREAD);

      }

      return new_ik;

    }

  }

#endif

  return NULL;

}

static ClassFileStream* check_class_file_load_hook(ClassFileStream* stream,

                                                   Symbol* name,

                                                   ClassLoaderData* loader_data,

                                                   Handle protection_domain,

                                                   JvmtiCachedClassFileData** cached_class_file,

                                                   TRAPS) {

  assert(stream != NULL, "invariant");

  if (JvmtiExport::should_post_class_file_load_hook()) {

    assert(THREAD->is_Java_thread(), "must be a JavaThread");

    const JavaThread* jt = (JavaThread*)THREAD;

    Handle class_loader(THREAD, loader_data->class_loader());

    // Get the cached class file bytes (if any) from the class that

    // is being redefined or retransformed. We use jvmti_thread_state()

    // instead of JvmtiThreadState::state_for(jt) so we don't allocate

    // a JvmtiThreadState any earlier than necessary. This will help

    // avoid the bug described by 7126851.

    JvmtiThreadState* state = jt->jvmti_thread_state();

    if (state != NULL) {

      Klass* k = state->get_class_being_redefined();

      if (k != NULL) {

        InstanceKlass* class_being_redefined = InstanceKlass::cast(k);

        *cached_class_file = class_being_redefined->get_cached_class_file();

      }

    }

    unsigned char* ptr = const_cast<unsigned char*>(stream->buffer());

    unsigned char* end_ptr = ptr + stream->length();

    JvmtiExport::post_class_file_load_hook(name,

                                           class_loader,

                                           protection_domain,

                                           &ptr,

                                           &end_ptr,

                                           cached_class_file);

    if (ptr != stream->buffer()) {

      // JVMTI agent has modified class file data.

      // Set new class file stream using JVMTI agent modified class file data.

      stream = new ClassFileStream(ptr,

                                   end_ptr - ptr,

                                   stream->source(),

                                   stream->need_verify());

    }

  }

  return stream;

}

InstanceKlass* KlassFactory::create_from_stream(ClassFileStream* stream,

                                                Symbol* name,

                                                ClassLoaderData* loader_data,

                                                Handle protection_domain,

                                                const InstanceKlass* host_klass,

                                                GrowableArray<Handle>* cp_patches,

                                                TRAPS) {

  assert(stream != NULL, "invariant");

  assert(loader_data != NULL, "invariant");

  assert(THREAD->is_Java_thread(), "must be a JavaThread");

  ResourceMark rm;

  HandleMark hm;

  JvmtiCachedClassFileData* cached_class_file = NULL;

  ClassFileStream* old_stream = stream;

  // Skip this processing for VM anonymous classes

  if (host_klass == NULL) {

    stream = check_class_file_load_hook(stream,

                                        name,

                                        loader_data,

                                        protection_domain,

                                        &cached_class_file,

                                        CHECK_NULL);

  }

  ClassFileParser parser(stream,

                         name,

                         loader_data,

                         protection_domain,

                         host_klass,

                         cp_patches,

                         ClassFileParser::BROADCAST, // publicity level

                         CHECK_NULL);

  InstanceKlass* result = parser.create_instance_klass(old_stream != stream, CHECK_NULL);

  assert(result == parser.create_instance_klass(old_stream != stream, THREAD), "invariant");

  if (result == NULL) {

    return NULL;

  }

  if (cached_class_file != NULL) {

    // JVMTI: we have an InstanceKlass now, tell it about the cached bytes

    result->set_cached_class_file(cached_class_file);

  }

  if (result->should_store_fingerprint()) {

    result->store_fingerprint(stream->compute_fingerprint());

  }

#if INCLUDE_CDS

  if (DumpSharedSpaces) {

    ClassLoader::record_result(result, stream, THREAD);

#if INCLUDE_JVMTI

    assert(cached_class_file == NULL, "Sanity");

    // Archive the class stream data into the optional data section

    JvmtiCachedClassFileData *p;

    int len;

    const unsigned char *bytes;

    // event based tracing might set cached_class_file

    if ((bytes = result->get_cached_class_file_bytes()) != NULL) {

      len = result->get_cached_class_file_len();

    } else {

      len = stream->length();

      bytes = stream->buffer();

    }

    p = (JvmtiCachedClassFileData*)os::malloc(offset_of(JvmtiCachedClassFileData, data) + len, mtInternal);

    p->length = len;

    memcpy(p->data, bytes, len);

    result->set_archived_class_data(p);

#endif // INCLUDE_JVMTI

  }

#endif // INCLUDE_CDS

  return result;

}