jdk

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/*
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 * Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "jvmtifiles/jvmtiEnv.hpp"
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#include "logging/log.hpp"
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#include "runtime/mutexLocker.hpp"
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#include "prims/jvmtiExport.hpp"
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#include "prims/jvmtiManageCapabilities.hpp"
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static const jint CAPA_SIZE = (JVMTI_INTERNAL_CAPABILITY_COUNT + 7) / 8;
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  // capabilities which are always potentially available
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jvmtiCapabilities JvmtiManageCapabilities::always_capabilities;
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  // capabilities which are potentially available during OnLoad
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jvmtiCapabilities JvmtiManageCapabilities::onload_capabilities;
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  // capabilities which are always potentially available
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  // but to only one environment
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jvmtiCapabilities JvmtiManageCapabilities::always_solo_capabilities;
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  // capabilities which are potentially available during OnLoad
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  // but to only one environment
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jvmtiCapabilities JvmtiManageCapabilities::onload_solo_capabilities;
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  // remaining capabilities which are always potentially available
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  // but to only one environment
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jvmtiCapabilities JvmtiManageCapabilities::always_solo_remaining_capabilities;
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  // remaining capabilities which are potentially available during OnLoad
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  // but to only one environment
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jvmtiCapabilities JvmtiManageCapabilities::onload_solo_remaining_capabilities;
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  // all capabilities ever acquired
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jvmtiCapabilities JvmtiManageCapabilities::acquired_capabilities;
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int JvmtiManageCapabilities::_can_support_virtual_threads_count = 0;
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Mutex* JvmtiManageCapabilities::_capabilities_lock = nullptr;
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void JvmtiManageCapabilities::initialize() {
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  _capabilities_lock = new Mutex(Mutex::nosafepoint, "Capabilities_lock");
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  always_capabilities = init_always_capabilities();
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  onload_capabilities = init_onload_capabilities();
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  always_solo_capabilities = init_always_solo_capabilities();
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  onload_solo_capabilities = init_onload_solo_capabilities();
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  always_solo_remaining_capabilities = init_always_solo_capabilities();
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  onload_solo_remaining_capabilities = init_onload_solo_capabilities();
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  memset(&acquired_capabilities, 0, sizeof(acquired_capabilities));
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}
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// corresponding init functions
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jvmtiCapabilities JvmtiManageCapabilities::init_always_capabilities() {
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  jvmtiCapabilities jc;
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  memset(&jc, 0, sizeof(jc));
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  jc.can_get_bytecodes = 1;
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  jc.can_signal_thread = 1;
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  jc.can_get_source_file_name = 1;
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  jc.can_get_line_numbers = 1;
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  jc.can_get_synthetic_attribute = 1;
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  jc.can_get_monitor_info = 1;
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  jc.can_get_constant_pool = 1;
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  jc.can_generate_all_class_hook_events = 1;
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  jc.can_generate_monitor_events = 1;
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  jc.can_generate_garbage_collection_events = 1;
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  jc.can_generate_compiled_method_load_events = 1;
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  jc.can_generate_native_method_bind_events = 1;
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  jc.can_generate_vm_object_alloc_events = 1;
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  if (os::is_thread_cpu_time_supported()) {
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    jc.can_get_current_thread_cpu_time = 1;
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    jc.can_get_thread_cpu_time = 1;
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  }
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  jc.can_redefine_classes = 1;
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  jc.can_redefine_any_class = 1;
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  jc.can_retransform_classes = 1;
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  jc.can_retransform_any_class = 1;
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  jc.can_set_native_method_prefix = 1;
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  jc.can_tag_objects = 1;
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  jc.can_generate_object_free_events = 1;
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  jc.can_generate_resource_exhaustion_heap_events = 1;
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  jc.can_generate_resource_exhaustion_threads_events = 1;
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  jc.can_support_virtual_threads = 1;
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  return jc;
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}
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jvmtiCapabilities JvmtiManageCapabilities::init_onload_capabilities() {
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  jvmtiCapabilities jc;
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  memset(&jc, 0, sizeof(jc));
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#ifndef ZERO
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  jc.can_pop_frame = 1;
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  jc.can_force_early_return = 1;
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#endif // !ZERO
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  jc.can_get_source_debug_extension = 1;
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  jc.can_access_local_variables = 1;
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  jc.can_maintain_original_method_order = 1;
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  jc.can_generate_single_step_events = 1;
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  jc.can_generate_exception_events = 1;
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  jc.can_generate_frame_pop_events = 1;
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  jc.can_generate_method_entry_events = 1;
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  jc.can_generate_method_exit_events = 1;
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  jc.can_get_owned_monitor_info = 1;
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  jc.can_get_owned_monitor_stack_depth_info = 1;
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  jc.can_get_current_contended_monitor = 1;
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  jc.can_generate_early_vmstart = 1;
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  jc.can_generate_early_class_hook_events = 1;
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  return jc;
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}
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jvmtiCapabilities JvmtiManageCapabilities::init_always_solo_capabilities() {
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  jvmtiCapabilities jc;
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  memset(&jc, 0, sizeof(jc));
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  jc.can_suspend = 1;
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  jc.can_generate_sampled_object_alloc_events = 1;
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  return jc;
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}
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jvmtiCapabilities JvmtiManageCapabilities::init_onload_solo_capabilities() {
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  jvmtiCapabilities jc;
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  memset(&jc, 0, sizeof(jc));
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  jc.can_generate_field_modification_events = 1;
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  jc.can_generate_field_access_events = 1;
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  jc.can_generate_breakpoint_events = 1;
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  return jc;
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}
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jvmtiCapabilities *JvmtiManageCapabilities::either(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
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                                                   jvmtiCapabilities *result) {
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  char *ap = (char *)a;
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  char *bp = (char *)b;
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  char *resultp = (char *)result;
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  for (int i = 0; i < CAPA_SIZE; ++i) {
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    *resultp++ = *ap++ | *bp++;
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  }
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  return result;
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}
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jvmtiCapabilities *JvmtiManageCapabilities::both(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
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                                                    jvmtiCapabilities *result) {
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  char *ap = (char *)a;
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  char *bp = (char *)b;
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  char *resultp = (char *)result;
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  for (int i = 0; i < CAPA_SIZE; ++i) {
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    *resultp++ = *ap++ & *bp++;
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  }
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  return result;
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}
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jvmtiCapabilities *JvmtiManageCapabilities::exclude(const jvmtiCapabilities *a, const jvmtiCapabilities *b,
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                                                    jvmtiCapabilities *result) {
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  char *ap = (char *)a;
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  char *bp = (char *)b;
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  char *resultp = (char *)result;
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  for (int i = 0; i < CAPA_SIZE; ++i) {
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    *resultp++ = *ap++ & (char)~*bp++;
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  }
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  return result;
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}
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bool JvmtiManageCapabilities::has_some(const jvmtiCapabilities *a) {
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  char *ap = (char *)a;
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  for (int i = 0; i < CAPA_SIZE; ++i) {
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    if (*ap++ != 0) {
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      return true;
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    }
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  }
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  return false;
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}
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void JvmtiManageCapabilities::copy_capabilities(const jvmtiCapabilities *from, jvmtiCapabilities *to) {
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  char *ap = (char *)from;
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  char *resultp = (char *)to;
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  for (int i = 0; i < CAPA_SIZE; ++i) {
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    *resultp++ = *ap++;
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  }
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}
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void JvmtiManageCapabilities::get_potential_capabilities_nolock(const jvmtiCapabilities *current,
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                                                         const jvmtiCapabilities *prohibited,
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                                                         jvmtiCapabilities *result) {
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  // exclude prohibited capabilities, must be before adding current
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  exclude(&always_capabilities, prohibited, result);
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  // must include current since it may possess solo capabilities and now prohibited
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  either(result, current, result);
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  // add other remaining
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  either(result, &always_solo_remaining_capabilities, result);
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  // if this is during OnLoad more capabilities are available
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  if (JvmtiEnv::get_phase() == JVMTI_PHASE_ONLOAD) {
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    either(result, &onload_capabilities, result);
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    either(result, &onload_solo_remaining_capabilities, result);
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  }
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}
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void JvmtiManageCapabilities::get_potential_capabilities(const jvmtiCapabilities* current,
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                                                         const jvmtiCapabilities* prohibited,
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                                                         jvmtiCapabilities* result) {
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  CapabilitiesMutexLocker ml;
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  get_potential_capabilities_nolock(current, prohibited, result);
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}
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jvmtiError JvmtiManageCapabilities::add_capabilities(const jvmtiCapabilities *current,
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                                                     const jvmtiCapabilities *prohibited,
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                                                     const jvmtiCapabilities *desired,
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                                                     jvmtiCapabilities *result) {
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  CapabilitiesMutexLocker ml;
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  // check that the capabilities being added are potential capabilities
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  jvmtiCapabilities temp;
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  get_potential_capabilities_nolock(current, prohibited, &temp);
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  if (has_some(exclude(desired, &temp, &temp))) {
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    return JVMTI_ERROR_NOT_AVAILABLE;
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  }
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  // add to the set of ever acquired capabilities
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  either(&acquired_capabilities, desired, &acquired_capabilities);
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  // onload capabilities that got added are now permanent - so, also remove from onload
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  both(&onload_capabilities, desired, &temp);
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  either(&always_capabilities, &temp, &always_capabilities);
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  exclude(&onload_capabilities, &temp, &onload_capabilities);
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  // same for solo capabilities (transferred capabilities in the remaining sets handled as part of standard grab - below)
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  both(&onload_solo_capabilities, desired, &temp);
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  either(&always_solo_capabilities, &temp, &always_solo_capabilities);
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  exclude(&onload_solo_capabilities, &temp, &onload_solo_capabilities);
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  // remove solo capabilities that are now taken
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  exclude(&always_solo_remaining_capabilities, desired, &always_solo_remaining_capabilities);
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  exclude(&onload_solo_remaining_capabilities, desired, &onload_solo_remaining_capabilities);
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  if (desired->can_support_virtual_threads != 0 && current->can_support_virtual_threads == 0) {
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    _can_support_virtual_threads_count++;
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  }
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  // return the result
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  either(current, desired, result);
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  update();
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  return JVMTI_ERROR_NONE;
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}
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void JvmtiManageCapabilities::relinquish_capabilities(const jvmtiCapabilities *current,
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                                                      const jvmtiCapabilities *unwanted,
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                                                      jvmtiCapabilities *result) {
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  CapabilitiesMutexLocker ml;
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  jvmtiCapabilities to_trash;
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  jvmtiCapabilities temp;
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  // can't give up what you don't have
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  both(current, unwanted, &to_trash);
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  // restore solo capabilities but only those that belong
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  either(&always_solo_remaining_capabilities, both(&always_solo_capabilities, &to_trash, &temp),
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         &always_solo_remaining_capabilities);
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  either(&onload_solo_remaining_capabilities, both(&onload_solo_capabilities, &to_trash, &temp),
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         &onload_solo_remaining_capabilities);
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  if (to_trash.can_support_virtual_threads != 0) {
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    assert(current->can_support_virtual_threads != 0, "sanity check");
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    assert(_can_support_virtual_threads_count > 0, "sanity check");
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    _can_support_virtual_threads_count--;
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  }
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  update();
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  // return the result
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  exclude(current, unwanted, result);
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}
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void JvmtiManageCapabilities::update() {
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  jvmtiCapabilities avail;
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  // all capabilities
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  either(&always_capabilities, &always_solo_capabilities, &avail);
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  bool interp_events =
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    avail.can_generate_field_access_events ||
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    avail.can_generate_field_modification_events ||
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    avail.can_generate_single_step_events ||
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    avail.can_generate_frame_pop_events ||
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    avail.can_generate_method_entry_events ||
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    avail.can_generate_method_exit_events;
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#ifdef ZERO
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  bool enter_all_methods =
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    interp_events ||
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    avail.can_generate_breakpoint_events;
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  if (enter_all_methods) {
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    // Disable these when tracking the bytecodes
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    UseFastEmptyMethods = false;
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    UseFastAccessorMethods = false;
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  }
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#endif // ZERO
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  if (avail.can_generate_breakpoint_events
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       || avail.can_generate_field_access_events
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       || avail.can_generate_field_modification_events)
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  {
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    RewriteFrequentPairs = false;
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#ifdef ZERO
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    // The BytecodeInterpreter is specialized only with RewriteBytecodes
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    // for simplicity. If we want to disable RewriteFrequentPairs, we
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    // need to disable RewriteBytecodes as well.
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    RewriteBytecodes = false;
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#endif
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  }
357

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  // If can_redefine_classes is enabled in the onload phase then we know that the
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  // dependency information recorded by the compiler is complete.
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  if ((avail.can_redefine_classes || avail.can_retransform_classes) &&
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      JvmtiEnv::get_phase() == JVMTI_PHASE_ONLOAD) {
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    JvmtiExport::set_all_dependencies_are_recorded(true);
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  }
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  JvmtiExport::set_can_get_source_debug_extension(avail.can_get_source_debug_extension);
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  JvmtiExport::set_can_maintain_original_method_order(avail.can_maintain_original_method_order);
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  JvmtiExport::set_can_post_interpreter_events(interp_events);
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  JvmtiExport::set_can_hotswap_or_post_breakpoint(
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    avail.can_generate_breakpoint_events ||
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    avail.can_redefine_classes ||
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    avail.can_retransform_classes);
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  JvmtiExport::set_can_modify_any_class(
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    avail.can_generate_breakpoint_events ||
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    avail.can_generate_all_class_hook_events);
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  JvmtiExport::set_can_walk_any_space(
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    avail.can_tag_objects);   // disable sharing in onload phase
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  // This controls whether the compilers keep extra locals live to
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  // improve the debugging experience so only set them if the selected
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  // capabilities look like a debugger.
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  JvmtiExport::set_can_access_local_variables(
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    avail.can_access_local_variables ||
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    avail.can_generate_breakpoint_events ||
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    avail.can_generate_frame_pop_events);
384
  JvmtiExport::set_can_post_on_exceptions(
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    avail.can_generate_exception_events ||
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    avail.can_generate_frame_pop_events ||
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    avail.can_generate_method_exit_events);
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  JvmtiExport::set_can_post_breakpoint(avail.can_generate_breakpoint_events);
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  JvmtiExport::set_can_post_field_access(avail.can_generate_field_access_events);
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  JvmtiExport::set_can_post_field_modification(avail.can_generate_field_modification_events);
391
  JvmtiExport::set_can_post_method_entry(avail.can_generate_method_entry_events);
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  JvmtiExport::set_can_post_method_exit(avail.can_generate_method_exit_events ||
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                                        avail.can_generate_frame_pop_events);
394
  JvmtiExport::set_can_post_frame_pop(avail.can_generate_frame_pop_events);
395
  JvmtiExport::set_can_pop_frame(avail.can_pop_frame);
396
  JvmtiExport::set_can_force_early_return(avail.can_force_early_return);
397
  JvmtiExport::set_can_support_virtual_threads(_can_support_virtual_threads_count != 0);
398
  JvmtiExport::set_should_clean_up_heap_objects(avail.can_generate_breakpoint_events);
399
  JvmtiExport::set_can_get_owned_monitor_info(avail.can_get_owned_monitor_info ||
400
                                              avail.can_get_owned_monitor_stack_depth_info);
401
}
402

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#ifndef PRODUCT
404

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void JvmtiManageCapabilities:: print(const jvmtiCapabilities* cap) {
406
  log_trace(jvmti)("----- capabilities -----");
407
  if (cap->can_tag_objects)
408
    log_trace(jvmti)("can_tag_objects");
409
  if (cap->can_generate_field_modification_events)
410
    log_trace(jvmti)("can_generate_field_modification_events");
411
  if (cap->can_generate_field_access_events)
412
    log_trace(jvmti)("can_generate_field_access_events");
413
  if (cap->can_get_bytecodes)
414
    log_trace(jvmti)("can_get_bytecodes");
415
  if (cap->can_get_synthetic_attribute)
416
    log_trace(jvmti)("can_get_synthetic_attribute");
417
  if (cap->can_get_owned_monitor_info)
418
    log_trace(jvmti)("can_get_owned_monitor_info");
419
  if (cap->can_get_current_contended_monitor)
420
    log_trace(jvmti)("can_get_current_contended_monitor");
421
  if (cap->can_get_monitor_info)
422
    log_trace(jvmti)("can_get_monitor_info");
423
  if (cap->can_get_constant_pool)
424
    log_trace(jvmti)("can_get_constant_pool");
425
  if (cap->can_pop_frame)
426
    log_trace(jvmti)("can_pop_frame");
427
  if (cap->can_force_early_return)
428
    log_trace(jvmti)("can_force_early_return");
429
  if (cap->can_redefine_classes)
430
    log_trace(jvmti)("can_redefine_classes");
431
  if (cap->can_retransform_classes)
432
    log_trace(jvmti)("can_retransform_classes");
433
  if (cap->can_signal_thread)
434
    log_trace(jvmti)("can_signal_thread");
435
  if (cap->can_get_source_file_name)
436
    log_trace(jvmti)("can_get_source_file_name");
437
  if (cap->can_get_line_numbers)
438
    log_trace(jvmti)("can_get_line_numbers");
439
  if (cap->can_get_source_debug_extension)
440
    log_trace(jvmti)("can_get_source_debug_extension");
441
  if (cap->can_access_local_variables)
442
    log_trace(jvmti)("can_access_local_variables");
443
  if (cap->can_maintain_original_method_order)
444
    log_trace(jvmti)("can_maintain_original_method_order");
445
  if (cap->can_generate_single_step_events)
446
    log_trace(jvmti)("can_generate_single_step_events");
447
  if (cap->can_generate_exception_events)
448
    log_trace(jvmti)("can_generate_exception_events");
449
  if (cap->can_generate_frame_pop_events)
450
    log_trace(jvmti)("can_generate_frame_pop_events");
451
  if (cap->can_generate_breakpoint_events)
452
    log_trace(jvmti)("can_generate_breakpoint_events");
453
  if (cap->can_generate_sampled_object_alloc_events)
454
    log_trace(jvmti)("can_generate_sampled_object_alloc_events");
455
  if (cap->can_suspend)
456
    log_trace(jvmti)("can_suspend");
457
  if (cap->can_redefine_any_class )
458
    log_trace(jvmti)("can_redefine_any_class");
459
  if (cap->can_retransform_any_class )
460
    log_trace(jvmti)("can_retransform_any_class");
461
  if (cap->can_get_current_thread_cpu_time)
462
    log_trace(jvmti)("can_get_current_thread_cpu_time");
463
  if (cap->can_get_thread_cpu_time)
464
    log_trace(jvmti)("can_get_thread_cpu_time");
465
  if (cap->can_generate_method_entry_events)
466
    log_trace(jvmti)("can_generate_method_entry_events");
467
  if (cap->can_generate_method_exit_events)
468
    log_trace(jvmti)("can_generate_method_exit_events");
469
  if (cap->can_generate_all_class_hook_events)
470
    log_trace(jvmti)("can_generate_all_class_hook_events");
471
  if (cap->can_generate_compiled_method_load_events)
472
    log_trace(jvmti)("can_generate_compiled_method_load_events");
473
  if (cap->can_generate_monitor_events)
474
    log_trace(jvmti)("can_generate_monitor_events");
475
  if (cap->can_generate_vm_object_alloc_events)
476
    log_trace(jvmti)("can_generate_vm_object_alloc_events");
477
  if (cap->can_generate_native_method_bind_events)
478
    log_trace(jvmti)("can_generate_native_method_bind_events");
479
  if (cap->can_generate_garbage_collection_events)
480
    log_trace(jvmti)("can_generate_garbage_collection_events");
481
  if (cap->can_generate_object_free_events)
482
    log_trace(jvmti)("can_generate_object_free_events");
483
  if (cap->can_generate_resource_exhaustion_heap_events)
484
    log_trace(jvmti)("can_generate_resource_exhaustion_heap_events");
485
  if (cap->can_generate_resource_exhaustion_threads_events)
486
    log_trace(jvmti)("can_generate_resource_exhaustion_threads_events");
487
  if (cap->can_generate_early_vmstart)
488
    log_trace(jvmti)("can_generate_early_vmstart");
489
  if (cap->can_generate_early_class_hook_events)
490
    log_trace(jvmti)("can_generate_early_class_hook_events");
491
  if (cap->can_support_virtual_threads)
492
    log_trace(jvmti)("can_support_virtual_threads");
493
}
494

495
#endif
496