1 /* 2 * Copyright (c) 2015, 2025, 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 "cds/cdsConfig.hpp" 26 #include "cds/filemap.hpp" 27 #include "classfile/classFileParser.hpp" 28 #include "classfile/classFileStream.hpp" 29 #include "classfile/classLoader.hpp" 30 #include "classfile/classLoaderData.hpp" 31 #include "classfile/classLoaderData.inline.hpp" 32 #include "classfile/classLoadInfo.hpp" 33 #include "classfile/klassFactory.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, 50 const ClassFileStream *cfs, 51 TRAPS) { 52 #if INCLUDE_CDS && INCLUDE_JVMTI 53 assert(ik != nullptr, "sanity"); 54 assert(ik->is_shared(), "expecting a shared class"); 55 if (JvmtiExport::should_post_class_file_load_hook()) { 56 ResourceMark rm(THREAD); 57 // Post the CFLH 58 JvmtiCachedClassFileData* cached_class_file = nullptr; 59 if (cfs == nullptr) { 60 cfs = FileMapInfo::open_stream_for_jvmti(ik, class_loader, CHECK_NULL); 61 } 62 unsigned char* ptr = (unsigned char*)cfs->buffer(); 63 unsigned char* end_ptr = ptr + cfs->length(); 64 unsigned char* old_ptr = ptr; 65 JvmtiExport::post_class_file_load_hook(class_name, 66 class_loader, 67 protection_domain, 68 &ptr, 69 &end_ptr, 70 &cached_class_file); 71 if (old_ptr != ptr) { 72 // JVMTI agent has modified class file data. 73 // Set new class file stream using JVMTI agent modified class file data. 74 ClassLoaderData* loader_data = 75 ClassLoaderData::class_loader_data(class_loader()); 76 s2 path_index = ik->shared_classpath_index(); 77 ClassFileStream* stream = new ClassFileStream(ptr, 78 pointer_delta_as_int(end_ptr, ptr), 79 cfs->source(), 80 /* from_boot_loader_modules_image */ false, 81 /* from_class_file_load_hook */ true); 82 ClassLoadInfo cl_info(protection_domain); 83 ClassFileParser parser(stream, 84 class_name, 85 loader_data, 86 &cl_info, 87 ClassFileParser::BROADCAST, // publicity level 88 CHECK_NULL); 89 const ClassInstanceInfo* cl_inst_info = cl_info.class_hidden_info_ptr(); 90 InstanceKlass* new_ik = parser.create_instance_klass(true, // changed_by_loadhook 91 *cl_inst_info, // dynamic_nest_host and classData 92 CHECK_NULL); 93 94 if (cached_class_file != nullptr) { 95 new_ik->set_cached_class_file(cached_class_file); 96 } 97 98 if (class_loader.is_null()) { 99 new_ik->set_classpath_index(path_index); 100 new_ik->assign_class_loader_type(); 101 } 102 103 return new_ik; 104 } 105 } 106 #endif 107 108 return nullptr; 109 } 110 111 112 static ClassFileStream* check_class_file_load_hook(ClassFileStream* stream, 113 Symbol* name, 114 ClassLoaderData* loader_data, 115 Handle protection_domain, 116 JvmtiCachedClassFileData** cached_class_file, 117 TRAPS) { 118 119 assert(stream != nullptr, "invariant"); 120 121 if (JvmtiExport::should_post_class_file_load_hook()) { 122 const JavaThread* jt = THREAD; 123 124 Handle class_loader(THREAD, loader_data->class_loader()); 125 126 // Get the cached class file bytes (if any) from the class that 127 // is being retransformed. If class file load hook provides 128 // modified class data during class loading or redefinition, 129 // new cached class file buffer should be allocated. 130 // We use jvmti_thread_state() 131 // instead of JvmtiThreadState::state_for(jt) so we don't allocate 132 // a JvmtiThreadState any earlier than necessary. This will help 133 // avoid the bug described by 7126851. 134 135 JvmtiThreadState* state = jt->jvmti_thread_state(); 136 137 if (state != nullptr) { 138 Klass* k = state->get_class_being_redefined(); 139 if (k != nullptr && state->get_class_load_kind() == jvmti_class_load_kind_retransform) { 140 InstanceKlass* class_being_redefined = InstanceKlass::cast(k); 141 *cached_class_file = class_being_redefined->get_cached_class_file(); 142 } 143 } 144 145 unsigned char* ptr = const_cast<unsigned char*>(stream->buffer()); 146 unsigned char* end_ptr = ptr + stream->length(); 147 148 JvmtiExport::post_class_file_load_hook(name, 149 class_loader, 150 protection_domain, 151 &ptr, 152 &end_ptr, 153 cached_class_file); 154 155 if (ptr != stream->buffer()) { 156 // JVMTI agent has modified class file data. 157 // Set new class file stream using JVMTI agent modified class file data. 158 stream = new ClassFileStream(ptr, 159 pointer_delta_as_int(end_ptr, ptr), 160 stream->source(), 161 /* from_boot_loader_modules_image */ false, 162 /* from_class_file_load_hook */ true); 163 } 164 } 165 166 return stream; 167 } 168 169 170 InstanceKlass* KlassFactory::create_from_stream(ClassFileStream* stream, 171 Symbol* name, 172 ClassLoaderData* loader_data, 173 const ClassLoadInfo& cl_info, 174 TRAPS) { 175 assert(stream != nullptr, "invariant"); 176 assert(loader_data != nullptr, "invariant"); 177 178 ResourceMark rm(THREAD); 179 HandleMark hm(THREAD); 180 181 JvmtiCachedClassFileData* cached_class_file = nullptr; 182 183 ClassFileStream* old_stream = stream; 184 185 // increment counter 186 THREAD->statistical_info().incr_define_class_count(); 187 188 // Skip this processing for VM hidden classes 189 if (!cl_info.is_hidden()) { 190 stream = check_class_file_load_hook(stream, 191 name, 192 loader_data, 193 cl_info.protection_domain(), 194 &cached_class_file, 195 CHECK_NULL); 196 } 197 198 ClassFileParser parser(stream, 199 name, 200 loader_data, 201 &cl_info, 202 ClassFileParser::BROADCAST, // publicity level 203 CHECK_NULL); 204 205 const ClassInstanceInfo* cl_inst_info = cl_info.class_hidden_info_ptr(); 206 InstanceKlass* result = parser.create_instance_klass(old_stream != stream, *cl_inst_info, CHECK_NULL); 207 assert(result != nullptr, "result cannot be null with no pending exception"); 208 209 if (cached_class_file != nullptr) { 210 // JVMTI: we have an InstanceKlass now, tell it about the cached bytes 211 result->set_cached_class_file(cached_class_file); 212 } 213 214 JFR_ONLY(ON_KLASS_CREATION(result, parser, THREAD);) 215 216 #if INCLUDE_CDS 217 if (CDSConfig::is_dumping_archive()) { 218 ClassLoader::record_result(THREAD, result, stream, old_stream != stream); 219 } 220 #endif // INCLUDE_CDS 221 222 return result; 223 }