1 /* Copyright (C) 2017 The Android Open Source Project
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This file implements interfaces from the file jvmti.h. This implementation
5 * is licensed under the same terms as the file jvmti.h. The
6 * copyright and license information for the file jvmti.h follows.
7 *
8 * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
9 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
10 *
11 * This code is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License version 2 only, as
13 * published by the Free Software Foundation. Oracle designates this
14 * particular file as subject to the "Classpath" exception as provided
15 * by Oracle in the LICENSE file that accompanied this code.
16 *
17 * This code is distributed in the hope that it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 * version 2 for more details (a copy is included in the LICENSE file that
21 * accompanied this code).
22 *
23 * You should have received a copy of the GNU General Public License version
24 * 2 along with this work; if not, write to the Free Software Foundation,
25 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
26 *
27 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
28 * or visit www.oracle.com if you need additional information or have any
29 * questions.
30 */
31
32 #include "ti_search.h"
33
34 #include "jni.h"
35
36 #include "art_field-inl.h"
37 #include "art_jvmti.h"
38 #include "base/enums.h"
39 #include "base/macros.h"
40 #include "class_linker.h"
41 #include "dex_file.h"
42 #include "jni_internal.h"
43 #include "mirror/class-inl.h"
44 #include "mirror/object.h"
45 #include "mirror/string.h"
46 #include "obj_ptr-inl.h"
47 #include "runtime.h"
48 #include "runtime_callbacks.h"
49 #include "scoped_thread_state_change-inl.h"
50 #include "ScopedLocalRef.h"
51 #include "ti_phase.h"
52 #include "thread-inl.h"
53 #include "thread_list.h"
54 #include "well_known_classes.h"
55
56 namespace openjdkjvmti {
57
58 static std::vector<std::string> gSystemOnloadSegments;
59
GetSystemProperties(art::Thread * self,art::ClassLinker * class_linker)60 static art::ObjPtr<art::mirror::Object> GetSystemProperties(art::Thread* self,
61 art::ClassLinker* class_linker)
62 REQUIRES_SHARED(art::Locks::mutator_lock_) {
63 art::ObjPtr<art::mirror::Class> system_class =
64 class_linker->LookupClass(self, "Ljava/lang/System;", nullptr);
65 DCHECK(system_class != nullptr);
66 DCHECK(system_class->IsInitialized());
67
68 art::ArtField* props_field =
69 system_class->FindDeclaredStaticField("props", "Ljava/util/Properties;");
70 DCHECK(props_field != nullptr);
71
72 art::ObjPtr<art::mirror::Object> props_obj = props_field->GetObject(system_class);
73 DCHECK(props_obj != nullptr);
74
75 return props_obj;
76 }
77
Update()78 static void Update() REQUIRES_SHARED(art::Locks::mutator_lock_) {
79 if (gSystemOnloadSegments.empty()) {
80 return;
81 }
82
83 // In the on-load phase we have to modify java.class.path to influence the system classloader.
84 // As this is an unmodifiable system property, we have to access the "defaults" field.
85 art::ClassLinker* class_linker = art::Runtime::Current()->GetClassLinker();
86 DCHECK(class_linker != nullptr);
87 art::Thread* self = art::Thread::Current();
88
89 // Prepare: collect classes, fields and methods.
90 art::ObjPtr<art::mirror::Class> properties_class =
91 class_linker->LookupClass(self, "Ljava/util/Properties;", nullptr);
92 DCHECK(properties_class != nullptr);
93
94 ScopedLocalRef<jobject> defaults_jobj(self->GetJniEnv(), nullptr);
95 {
96 art::ObjPtr<art::mirror::Object> props_obj = GetSystemProperties(self, class_linker);
97
98 art::ArtField* defaults_field =
99 properties_class->FindDeclaredInstanceField("defaults", "Ljava/util/Properties;");
100 DCHECK(defaults_field != nullptr);
101
102 art::ObjPtr<art::mirror::Object> defaults_obj = defaults_field->GetObject(props_obj);
103 DCHECK(defaults_obj != nullptr);
104 defaults_jobj.reset(self->GetJniEnv()->AddLocalReference<jobject>(defaults_obj));
105 }
106
107 art::ArtMethod* get_property =
108 properties_class->FindDeclaredVirtualMethod(
109 "getProperty",
110 "(Ljava/lang/String;)Ljava/lang/String;",
111 art::kRuntimePointerSize);
112 DCHECK(get_property != nullptr);
113 art::ArtMethod* set_property =
114 properties_class->FindDeclaredVirtualMethod(
115 "setProperty",
116 "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;",
117 art::kRuntimePointerSize);
118 DCHECK(set_property != nullptr);
119
120 // This is an allocation. Do this late to avoid the need for handles.
121 ScopedLocalRef<jobject> cp_jobj(self->GetJniEnv(), nullptr);
122 {
123 art::ObjPtr<art::mirror::Object> cp_key =
124 art::mirror::String::AllocFromModifiedUtf8(self, "java.class.path");
125 if (cp_key == nullptr) {
126 self->AssertPendingOOMException();
127 self->ClearException();
128 return;
129 }
130 cp_jobj.reset(self->GetJniEnv()->AddLocalReference<jobject>(cp_key));
131 }
132
133 // OK, now get the current value.
134 std::string str_value;
135 {
136 ScopedLocalRef<jobject> old_value(self->GetJniEnv(),
137 self->GetJniEnv()->CallObjectMethod(
138 defaults_jobj.get(),
139 art::jni::EncodeArtMethod(get_property),
140 cp_jobj.get()));
141 DCHECK(old_value.get() != nullptr);
142
143 str_value = self->DecodeJObject(old_value.get())->AsString()->ToModifiedUtf8();
144 self->GetJniEnv()->DeleteLocalRef(old_value.release());
145 }
146
147 // Update the value by appending the new segments.
148 for (const std::string& segment : gSystemOnloadSegments) {
149 if (!str_value.empty()) {
150 str_value += ":";
151 }
152 str_value += segment;
153 }
154 gSystemOnloadSegments.clear();
155
156 // Create the new value object.
157 ScopedLocalRef<jobject> new_val_jobj(self->GetJniEnv(), nullptr);
158 {
159 art::ObjPtr<art::mirror::Object> new_value =
160 art::mirror::String::AllocFromModifiedUtf8(self, str_value.c_str());
161 if (new_value == nullptr) {
162 self->AssertPendingOOMException();
163 self->ClearException();
164 return;
165 }
166
167 new_val_jobj.reset(self->GetJniEnv()->AddLocalReference<jobject>(new_value));
168 }
169
170 // Write to the defaults.
171 ScopedLocalRef<jobject> res_obj(self->GetJniEnv(),
172 self->GetJniEnv()->CallObjectMethod(defaults_jobj.get(),
173 art::jni::EncodeArtMethod(set_property),
174 cp_jobj.get(),
175 new_val_jobj.get()));
176 if (self->IsExceptionPending()) {
177 self->ClearException();
178 return;
179 }
180 }
181
182 struct SearchCallback : public art::RuntimePhaseCallback {
NextRuntimePhaseopenjdkjvmti::SearchCallback183 void NextRuntimePhase(RuntimePhase phase) OVERRIDE REQUIRES_SHARED(art::Locks::mutator_lock_) {
184 if (phase == RuntimePhase::kStart) {
185 // It's time to update the system properties.
186 Update();
187 }
188 }
189 };
190
191 static SearchCallback gSearchCallback;
192
Register()193 void SearchUtil::Register() {
194 art::Runtime* runtime = art::Runtime::Current();
195
196 art::ScopedThreadStateChange stsc(art::Thread::Current(),
197 art::ThreadState::kWaitingForDebuggerToAttach);
198 art::ScopedSuspendAll ssa("Add search callback");
199 runtime->GetRuntimeCallbacks()->AddRuntimePhaseCallback(&gSearchCallback);
200 }
201
Unregister()202 void SearchUtil::Unregister() {
203 art::ScopedThreadStateChange stsc(art::Thread::Current(),
204 art::ThreadState::kWaitingForDebuggerToAttach);
205 art::ScopedSuspendAll ssa("Remove search callback");
206 art::Runtime* runtime = art::Runtime::Current();
207 runtime->GetRuntimeCallbacks()->RemoveRuntimePhaseCallback(&gSearchCallback);
208 }
209
AddToBootstrapClassLoaderSearch(jvmtiEnv * env ATTRIBUTE_UNUSED,const char * segment)210 jvmtiError SearchUtil::AddToBootstrapClassLoaderSearch(jvmtiEnv* env ATTRIBUTE_UNUSED,
211 const char* segment) {
212 art::Runtime* current = art::Runtime::Current();
213 if (current == nullptr) {
214 return ERR(WRONG_PHASE);
215 }
216 if (current->GetClassLinker() == nullptr) {
217 return ERR(WRONG_PHASE);
218 }
219 if (segment == nullptr) {
220 return ERR(NULL_POINTER);
221 }
222
223 std::string error_msg;
224 std::vector<std::unique_ptr<const art::DexFile>> dex_files;
225 if (!art::DexFile::Open(segment, segment, true, &error_msg, &dex_files)) {
226 LOG(WARNING) << "Could not open " << segment << " for boot classpath extension: " << error_msg;
227 return ERR(ILLEGAL_ARGUMENT);
228 }
229
230 art::ScopedObjectAccess soa(art::Thread::Current());
231 for (std::unique_ptr<const art::DexFile>& dex_file : dex_files) {
232 current->GetClassLinker()->AppendToBootClassPath(art::Thread::Current(), *dex_file.release());
233 }
234
235 return ERR(NONE);
236 }
237
AddToSystemClassLoaderSearch(jvmtiEnv * jvmti_env ATTRIBUTE_UNUSED,const char * segment)238 jvmtiError SearchUtil::AddToSystemClassLoaderSearch(jvmtiEnv* jvmti_env ATTRIBUTE_UNUSED,
239 const char* segment) {
240 if (segment == nullptr) {
241 return ERR(NULL_POINTER);
242 }
243
244 jvmtiPhase phase = PhaseUtil::GetPhaseUnchecked();
245
246 if (phase == jvmtiPhase::JVMTI_PHASE_ONLOAD) {
247 // We could try and see whether it is a valid path. We could also try to allocate Java
248 // objects to avoid later OOME.
249 gSystemOnloadSegments.push_back(segment);
250 return ERR(NONE);
251 } else if (phase != jvmtiPhase::JVMTI_PHASE_LIVE) {
252 return ERR(WRONG_PHASE);
253 }
254
255 jobject sys_class_loader = art::Runtime::Current()->GetSystemClassLoader();
256 if (sys_class_loader == nullptr) {
257 // This is unexpected.
258 return ERR(INTERNAL);
259 }
260
261 // We'll use BaseDexClassLoader.addDexPath, as it takes care of array resizing etc. As a downside,
262 // exceptions are swallowed.
263
264 art::Thread* self = art::Thread::Current();
265 JNIEnv* env = self->GetJniEnv();
266 if (!env->IsInstanceOf(sys_class_loader,
267 art::WellKnownClasses::dalvik_system_BaseDexClassLoader)) {
268 return ERR(INTERNAL);
269 }
270
271 jmethodID add_dex_path_id = env->GetMethodID(
272 art::WellKnownClasses::dalvik_system_BaseDexClassLoader,
273 "addDexPath",
274 "(Ljava/lang/String;)V");
275 if (add_dex_path_id == nullptr) {
276 return ERR(INTERNAL);
277 }
278
279 ScopedLocalRef<jstring> dex_path(env, env->NewStringUTF(segment));
280 if (dex_path.get() == nullptr) {
281 return ERR(INTERNAL);
282 }
283 env->CallVoidMethod(sys_class_loader, add_dex_path_id, dex_path.get());
284
285 if (env->ExceptionCheck()) {
286 env->ExceptionClear();
287 return ERR(ILLEGAL_ARGUMENT);
288 }
289 return ERR(NONE);
290 }
291
292 } // namespace openjdkjvmti
293