1 /*
2 * Copyright (c) 2015, 2024, 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 "cds/cds_globals.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "cds/filemap.hpp"
29 #include "classfile/classFileParser.hpp"
30 #include "classfile/classFileStream.hpp"
31 #include "classfile/classLoader.hpp"
32 #include "classfile/classLoaderData.hpp"
33 #include "classfile/classLoaderData.inline.hpp"
34 #include "classfile/classLoadInfo.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "memory/resourceArea.hpp"
37 #include "prims/jvmtiEnvBase.hpp"
38 #include "prims/jvmtiRedefineClasses.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "utilities/macros.hpp"
41 #if INCLUDE_JFR
42 #include "jfr/support/jfrKlassExtension.hpp"
43 #endif
44
45
46 // called during initial loading of a shared class
47 InstanceKlass* KlassFactory::check_shared_class_file_load_hook(
48 InstanceKlass* ik,
49 Symbol* class_name,
50 Handle class_loader,
51 Handle protection_domain,
52 const ClassFileStream *cfs,
53 TRAPS) {
54 #if INCLUDE_CDS && INCLUDE_JVMTI
55 assert(ik != nullptr, "sanity");
56 assert(ik->is_shared(), "expecting a shared class");
57 if (JvmtiExport::should_post_class_file_load_hook()) {
58 ResourceMark rm(THREAD);
59 // Post the CFLH
60 JvmtiCachedClassFileData* cached_class_file = nullptr;
61 if (cfs == nullptr) {
62 cfs = FileMapInfo::open_stream_for_jvmti(ik, class_loader, CHECK_NULL);
63 }
64 unsigned char* ptr = (unsigned char*)cfs->buffer();
65 unsigned char* end_ptr = ptr + cfs->length();
66 unsigned char* old_ptr = ptr;
67 JvmtiExport::post_class_file_load_hook(class_name,
68 class_loader,
69 protection_domain,
70 &ptr,
71 &end_ptr,
72 &cached_class_file);
73 if (old_ptr != ptr) {
74 // JVMTI agent has modified class file data.
75 // Set new class file stream using JVMTI agent modified class file data.
76 ClassLoaderData* loader_data =
77 ClassLoaderData::class_loader_data(class_loader());
78 s2 path_index = ik->shared_classpath_index();
79 ClassFileStream* stream = new ClassFileStream(ptr,
80 pointer_delta_as_int(end_ptr, ptr),
81 cfs->source());
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 }
162 }
163
164 return stream;
165 }
166
167
168 InstanceKlass* KlassFactory::create_from_stream(ClassFileStream* stream,
169 Symbol* name,
170 ClassLoaderData* loader_data,
171 const ClassLoadInfo& cl_info,
172 TRAPS) {
173 assert(stream != nullptr, "invariant");
174 assert(loader_data != nullptr, "invariant");
175
176 ResourceMark rm(THREAD);
177 HandleMark hm(THREAD);
178
179 JvmtiCachedClassFileData* cached_class_file = nullptr;
180
181 ClassFileStream* old_stream = stream;
182
183 // increment counter
184 THREAD->statistical_info().incr_define_class_count();
185
186 // Skip this processing for VM hidden classes
187 if (!cl_info.is_hidden()) {
188 stream = check_class_file_load_hook(stream,
189 name,
190 loader_data,
191 cl_info.protection_domain(),
192 &cached_class_file,
193 CHECK_NULL);
194 }
195
196 ClassFileParser parser(stream,
197 name,
198 loader_data,
199 &cl_info,
200 ClassFileParser::BROADCAST, // publicity level
201 CHECK_NULL);
202
203 const ClassInstanceInfo* cl_inst_info = cl_info.class_hidden_info_ptr();
204 InstanceKlass* result = parser.create_instance_klass(old_stream != stream, *cl_inst_info, CHECK_NULL);
205 assert(result != nullptr, "result cannot be null with no pending exception");
206
207 if (cached_class_file != nullptr) {
208 // JVMTI: we have an InstanceKlass now, tell it about the cached bytes
209 result->set_cached_class_file(cached_class_file);
210 }
211
212 JFR_ONLY(ON_KLASS_CREATION(result, parser, THREAD);)
213
214 #if INCLUDE_CDS
215 if (CDSConfig::is_dumping_archive()) {
216 ClassLoader::record_result(THREAD, result, stream, old_stream != stream);
217 }
218 #endif // INCLUDE_CDS
219
220 return result;
221 }