1 /*

     2  * Copyright (c) 2016, 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 "jfr/jni/jfrJavaSupport.hpp"

    27 #include "jfr/recorder/checkpoint/jfrMetadataEvent.hpp"

    28 #include "jfr/recorder/repository/jfrChunkWriter.hpp"

    29 #include "oops/klass.inline.hpp"

    30 #include "oops/oop.inline.hpp"

    31 #include "oops/typeArrayOop.inline.hpp"

    32 #include "runtime/semaphore.hpp"

    33 #include "runtime/thread.inline.hpp"

    34 

    35 static jbyteArray _metadata_blob = NULL;

    36 static Semaphore metadata_mutex_semaphore(1);

    37 

    38 void JfrMetadataEvent::lock() {

    39   metadata_mutex_semaphore.wait();

    40 }

    41 

    42 void JfrMetadataEvent::unlock() {

    43   metadata_mutex_semaphore.signal();

    44 }

    45 

    46 static void write_metadata_blob(JfrChunkWriter& chunkwriter, jbyteArray metadata_blob) {

    47   if (metadata_blob != NULL) {

    48     const typeArrayOop arr = (typeArrayOop)JfrJavaSupport::resolve_non_null(metadata_blob);

    49     assert(arr != NULL, "invariant");

    50     const int length = arr->length();

    51     const Klass* const k = arr->klass();

    52     assert(k != NULL && k->is_array_klass(), "invariant");

    53     const TypeArrayKlass* const byte_arr_klass = TypeArrayKlass::cast(k);

    54     const jbyte* const data_address = arr->byte_at_addr(0);

    55     chunkwriter.write_unbuffered(data_address, length);

    56   }

    57 }

    58 

    59 // the semaphore is assumed to be locked  (was locked previous safepoint)

    60 size_t JfrMetadataEvent::write(JfrChunkWriter& chunkwriter, jlong metadata_offset) {

    61   assert(chunkwriter.is_valid(), "invariant");

    62   assert(chunkwriter.current_offset() == metadata_offset, "invariant");

    63   // header

    64   chunkwriter.reserve(sizeof(u4));

    65   chunkwriter.write<u8>(EVENT_METADATA); // ID 0

    66   // time data

    67   chunkwriter.write(JfrTicks::now());

    68   chunkwriter.write((u8)0); // duration

    69   chunkwriter.write((u8)0); // metadata id

    70   write_metadata_blob(chunkwriter, _metadata_blob); // payload

    71   unlock(); // open up for java to provide updated metadata

    72   // fill in size of metadata descriptor event

    73   const jlong size_written = chunkwriter.current_offset() - metadata_offset;

    74   chunkwriter.write_padded_at_offset((u4)size_written, metadata_offset);

    75   return size_written;

    76 }

    77 

    78 void JfrMetadataEvent::update(jbyteArray metadata) {

    79   JavaThread* thread = (JavaThread*)Thread::current();

    80   assert(thread->is_Java_thread(), "invariant");

    81   DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(thread));

    82   lock();

    83   if (_metadata_blob != NULL) {

    84     JfrJavaSupport::destroy_global_jni_handle(_metadata_blob);

    85   }

    86   const oop new_desc_oop = JfrJavaSupport::resolve_non_null(metadata);

    87   _metadata_blob = new_desc_oop != NULL ? (jbyteArray)JfrJavaSupport::global_jni_handle(new_desc_oop, thread) : NULL;

    88   unlock();

    89 }