1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_RUNTIME_JNI_ENV_EXT_H_ 18 #define ART_RUNTIME_JNI_ENV_EXT_H_ 19 20 #include <jni.h> 21 22 #include "base/macros.h" 23 #include "base/mutex.h" 24 #include "indirect_reference_table.h" 25 #include "obj_ptr.h" 26 #include "reference_table.h" 27 28 namespace art { 29 30 class JavaVMExt; 31 32 namespace mirror { 33 class Object; 34 } // namespace mirror 35 36 // Number of local references in the indirect reference table. The value is arbitrary but 37 // low enough that it forces sanity checks. 38 static constexpr size_t kLocalsInitial = 512; 39 40 class JNIEnvExt : public JNIEnv { 41 public: 42 // Creates a new JNIEnvExt. Returns null on error, in which case error_msg 43 // will contain a description of the error. 44 static JNIEnvExt* Create(Thread* self, JavaVMExt* vm, std::string* error_msg); 45 static Offset SegmentStateOffset(size_t pointer_size); 46 static Offset LocalRefCookieOffset(size_t pointer_size); 47 static Offset SelfOffset(size_t pointer_size); 48 static jint GetEnvHandler(JavaVMExt* vm, /*out*/void** out, jint version); 49 50 ~JNIEnvExt(); 51 52 void DumpReferenceTables(std::ostream& os) 53 REQUIRES_SHARED(Locks::mutator_lock_) 54 REQUIRES(!Locks::alloc_tracker_lock_); 55 56 void SetCheckJniEnabled(bool enabled) REQUIRES(!Locks::jni_function_table_lock_); 57 58 void PushFrame(int capacity) REQUIRES_SHARED(Locks::mutator_lock_); 59 void PopFrame() REQUIRES_SHARED(Locks::mutator_lock_); 60 61 template<typename T> 62 T AddLocalReference(ObjPtr<mirror::Object> obj) 63 REQUIRES_SHARED(Locks::mutator_lock_) 64 REQUIRES(!Locks::alloc_tracker_lock_); 65 UpdateLocal(IndirectRef iref,ObjPtr<mirror::Object> obj)66 void UpdateLocal(IndirectRef iref, ObjPtr<mirror::Object> obj) REQUIRES_SHARED(Locks::mutator_lock_) { 67 locals_.Update(iref, obj); 68 } 69 70 jobject NewLocalRef(mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_); 71 void DeleteLocalRef(jobject obj) REQUIRES_SHARED(Locks::mutator_lock_); 72 TrimLocals()73 void TrimLocals() REQUIRES_SHARED(Locks::mutator_lock_) { 74 locals_.Trim(); 75 } AssertLocalsEmpty()76 void AssertLocalsEmpty() REQUIRES_SHARED(Locks::mutator_lock_) { 77 locals_.AssertEmpty(); 78 } GetLocalsCapacity()79 size_t GetLocalsCapacity() REQUIRES_SHARED(Locks::mutator_lock_) { 80 return locals_.Capacity(); 81 } 82 GetLocalRefCookie()83 IRTSegmentState GetLocalRefCookie() const { return local_ref_cookie_; } SetLocalRefCookie(IRTSegmentState new_cookie)84 void SetLocalRefCookie(IRTSegmentState new_cookie) { local_ref_cookie_ = new_cookie; } 85 GetLocalsSegmentState()86 IRTSegmentState GetLocalsSegmentState() const REQUIRES_SHARED(Locks::mutator_lock_) { 87 return locals_.GetSegmentState(); 88 } SetLocalSegmentState(IRTSegmentState new_state)89 void SetLocalSegmentState(IRTSegmentState new_state) REQUIRES_SHARED(Locks::mutator_lock_) { 90 locals_.SetSegmentState(new_state); 91 } 92 VisitJniLocalRoots(RootVisitor * visitor,const RootInfo & root_info)93 void VisitJniLocalRoots(RootVisitor* visitor, const RootInfo& root_info) 94 REQUIRES_SHARED(Locks::mutator_lock_) { 95 locals_.VisitRoots(visitor, root_info); 96 } 97 GetSelf()98 Thread* GetSelf() const { return self_; } GetCritical()99 uint32_t GetCritical() const { return critical_; } SetCritical(uint32_t new_critical)100 void SetCritical(uint32_t new_critical) { critical_ = new_critical; } GetCriticalStartUs()101 uint64_t GetCriticalStartUs() const { return critical_start_us_; } SetCriticalStartUs(uint64_t new_critical_start_us)102 void SetCriticalStartUs(uint64_t new_critical_start_us) { 103 critical_start_us_ = new_critical_start_us; 104 } GetUncheckedFunctions()105 const JNINativeInterface* GetUncheckedFunctions() const { 106 return unchecked_functions_; 107 } GetVm()108 JavaVMExt* GetVm() const { return vm_; } 109 IsRuntimeDeleted()110 bool IsRuntimeDeleted() const { return runtime_deleted_; } IsCheckJniEnabled()111 bool IsCheckJniEnabled() const { return check_jni_; } 112 113 114 // Functions to keep track of monitor lock and unlock operations. Used to ensure proper locking 115 // rules in CheckJNI mode. 116 117 // Record locking of a monitor. 118 void RecordMonitorEnter(jobject obj) REQUIRES_SHARED(Locks::mutator_lock_); 119 120 // Check the release, that is, that the release is performed in the same JNI "segment." 121 void CheckMonitorRelease(jobject obj) REQUIRES_SHARED(Locks::mutator_lock_); 122 123 // Check that no monitors are held that have been acquired in this JNI "segment." 124 void CheckNoHeldMonitors() REQUIRES_SHARED(Locks::mutator_lock_); 125 VisitMonitorRoots(RootVisitor * visitor,const RootInfo & root_info)126 void VisitMonitorRoots(RootVisitor* visitor, const RootInfo& root_info) 127 REQUIRES_SHARED(Locks::mutator_lock_) { 128 monitors_.VisitRoots(visitor, root_info); 129 } 130 131 // Set the functions to the runtime shutdown functions. 132 void SetFunctionsToRuntimeShutdownFunctions(); 133 134 // Set the function table override. This will install the override (or original table, if null) 135 // to all threads. 136 // Note: JNI function table overrides are sensitive to the order of operations wrt/ CheckJNI. 137 // After overriding the JNI function table, CheckJNI toggling is ignored. 138 static void SetTableOverride(const JNINativeInterface* table_override) 139 REQUIRES(!Locks::thread_list_lock_, !Locks::jni_function_table_lock_); 140 141 // Return either the regular, or the CheckJNI function table. Will return table_override_ instead 142 // if it is not null. 143 static const JNINativeInterface* GetFunctionTable(bool check_jni) 144 REQUIRES(Locks::jni_function_table_lock_); 145 146 private: 147 // Checking "locals" requires the mutator lock, but at creation time we're 148 // really only interested in validity, which isn't changing. To avoid grabbing 149 // the mutator lock, factored out and tagged with NO_THREAD_SAFETY_ANALYSIS. 150 static bool CheckLocalsValid(JNIEnvExt* in) NO_THREAD_SAFETY_ANALYSIS; 151 152 // Override of function tables. This applies to both default as well as instrumented (CheckJNI) 153 // function tables. 154 static const JNINativeInterface* table_override_ GUARDED_BY(Locks::jni_function_table_lock_); 155 156 // The constructor should not be called directly. It may leave the object in an erroneous state, 157 // and the result needs to be checked. 158 JNIEnvExt(Thread* self, JavaVMExt* vm, std::string* error_msg) 159 REQUIRES(!Locks::jni_function_table_lock_); 160 161 // Link to Thread::Current(). 162 Thread* const self_; 163 164 // The invocation interface JavaVM. 165 JavaVMExt* const vm_; 166 167 // Cookie used when using the local indirect reference table. 168 IRTSegmentState local_ref_cookie_; 169 170 // JNI local references. 171 IndirectReferenceTable locals_ GUARDED_BY(Locks::mutator_lock_); 172 173 // Stack of cookies corresponding to PushLocalFrame/PopLocalFrame calls. 174 // TODO: to avoid leaks (and bugs), we need to clear this vector on entry (or return) 175 // to a native method. 176 std::vector<IRTSegmentState> stacked_local_ref_cookies_; 177 178 // Entered JNI monitors, for bulk exit on thread detach. 179 ReferenceTable monitors_; 180 181 // Used by -Xcheck:jni. 182 const JNINativeInterface* unchecked_functions_; 183 184 // All locked objects, with the (Java caller) stack frame that locked them. Used in CheckJNI 185 // to ensure that only monitors locked in this native frame are being unlocked, and that at 186 // the end all are unlocked. 187 std::vector<std::pair<uintptr_t, jobject>> locked_objects_; 188 189 // Start time of "critical" JNI calls to ensure that their use doesn't 190 // excessively block the VM with CheckJNI. 191 uint64_t critical_start_us_; 192 193 // How many nested "critical" JNI calls are we in? Used by CheckJNI to ensure that criticals are 194 uint32_t critical_; 195 196 // Frequently-accessed fields cached from JavaVM. 197 bool check_jni_; 198 199 // If we are a JNI env for a daemon thread with a deleted runtime. 200 bool runtime_deleted_; 201 202 friend class JNI; 203 friend class ScopedJniEnvLocalRefState; 204 friend class Thread; 205 ART_FRIEND_TEST(JniInternalTest, JNIEnvExtOffsets); 206 }; 207 208 // Used to save and restore the JNIEnvExt state when not going through code created by the JNI 209 // compiler. 210 class ScopedJniEnvLocalRefState { 211 public: ScopedJniEnvLocalRefState(JNIEnvExt * env)212 explicit ScopedJniEnvLocalRefState(JNIEnvExt* env) : 213 env_(env), 214 saved_local_ref_cookie_(env->local_ref_cookie_) { 215 env->local_ref_cookie_ = env->locals_.GetSegmentState(); 216 } 217 ~ScopedJniEnvLocalRefState()218 ~ScopedJniEnvLocalRefState() { 219 env_->locals_.SetSegmentState(env_->local_ref_cookie_); 220 env_->local_ref_cookie_ = saved_local_ref_cookie_; 221 } 222 223 private: 224 JNIEnvExt* const env_; 225 const IRTSegmentState saved_local_ref_cookie_; 226 227 DISALLOW_COPY_AND_ASSIGN(ScopedJniEnvLocalRefState); 228 }; 229 230 } // namespace art 231 232 #endif // ART_RUNTIME_JNI_ENV_EXT_H_ 233