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 #ifndef ART_OPENJDKJVMTI_TI_THREAD_H_ 33 #define ART_OPENJDKJVMTI_TI_THREAD_H_ 34 35 #include <unordered_map> 36 37 #include "jni.h" 38 #include "jvmti.h" 39 40 #include "base/macros.h" 41 #include "base/mutex.h" 42 #include "thread.h" 43 44 namespace art { 45 class ArtField; 46 class ScopedObjectAccessAlreadyRunnable; 47 class Thread; 48 class Closure; 49 } // namespace art 50 51 namespace openjdkjvmti { 52 53 class EventHandler; 54 55 // Gains the user_code_suspension_lock_ and ensures that the code will not suspend for user-code. 56 class SCOPED_CAPABILITY ScopedNoUserCodeSuspension { 57 public: 58 explicit ScopedNoUserCodeSuspension(art::Thread* self) 59 ACQUIRE(art::Locks::user_code_suspension_lock_); 60 ~ScopedNoUserCodeSuspension() RELEASE(art::Locks::user_code_suspension_lock_); 61 62 private: 63 art::Thread* self_; 64 }; 65 66 // The struct that we store in the art::Thread::custom_tls_ that maps the jvmtiEnvs to the data 67 // stored with that thread. This is needed since different jvmtiEnvs are not supposed to share TLS 68 // data but we only have a single slot in Thread objects to store data. 69 struct JvmtiGlobalTLSData : public art::TLSData { 70 std::unordered_map<jvmtiEnv*, const void*> data GUARDED_BY(art::Locks::thread_list_lock_); 71 72 // The depth of the last frame where popping using PopFrame it is not allowed. It is set to 73 // kNoDisallowedPopFrame if all frames can be popped. See b/117615146 for more information. 74 static constexpr size_t kNoDisallowedPopFrame = -1; 75 size_t disable_pop_frame_depth = kNoDisallowedPopFrame; 76 }; 77 78 class ThreadUtil { 79 public: 80 static void Register(EventHandler* event_handler); 81 static void Unregister(); 82 83 // To be called when it is safe to cache data. This means that we have at least entered the 84 // RuntimePhase::kInit but we might or might not have already called VMInit event. 85 static void CacheData(); 86 87 // Called just after we have sent the VMInit callback so that ThreadUtil can do final setup. This 88 // ensures that there are no timing issues between the two callbacks. 89 static void VMInitEventSent() REQUIRES_SHARED(art::Locks::mutator_lock_); 90 91 // Handle a jvmtiEnv going away. 92 static void RemoveEnvironment(jvmtiEnv* env); 93 94 static jvmtiError GetAllThreads(jvmtiEnv* env, jint* threads_count_ptr, jthread** threads_ptr); 95 96 static jvmtiError GetCurrentThread(jvmtiEnv* env, jthread* thread_ptr); 97 98 static jvmtiError GetThreadInfo(jvmtiEnv* env, jthread thread, jvmtiThreadInfo* info_ptr); 99 100 static jvmtiError GetThreadState(jvmtiEnv* env, jthread thread, jint* thread_state_ptr); 101 102 static jvmtiError SetThreadLocalStorage(jvmtiEnv* env, jthread thread, const void* data); 103 static jvmtiError GetThreadLocalStorage(jvmtiEnv* env, jthread thread, void** data_ptr); 104 105 static jvmtiError RunAgentThread(jvmtiEnv* env, 106 jthread thread, 107 jvmtiStartFunction proc, 108 const void* arg, 109 jint priority); 110 111 static jvmtiError SuspendThread(jvmtiEnv* env, jthread thread); 112 static jvmtiError ResumeThread(jvmtiEnv* env, jthread thread); 113 114 static jvmtiError SuspendThreadList(jvmtiEnv* env, 115 jint request_count, 116 const jthread* threads, 117 jvmtiError* results); 118 static jvmtiError ResumeThreadList(jvmtiEnv* env, 119 jint request_count, 120 const jthread* threads, 121 jvmtiError* results); 122 123 static jvmtiError StopThread(jvmtiEnv* env, jthread thr, jobject exception); 124 static jvmtiError InterruptThread(jvmtiEnv* env, jthread thr); 125 126 // Returns true if we decoded the thread and it is alive, false otherwise with an appropriate 127 // error placed into 'err'. A thread is alive if it has had it's 'start' function called and has 128 // (or at least could have) executed managed code and has not yet returned past it's first managed 129 // frame. This means that the thread returned might have IsStillStarting() return true. Code that 130 // does not consider that alive should check manually. 131 static bool GetAliveNativeThread(jthread thread, 132 const art::ScopedObjectAccessAlreadyRunnable& soa, 133 /*out*/ art::Thread** thr, 134 /*out*/ jvmtiError* err) 135 REQUIRES_SHARED(art::Locks::mutator_lock_) 136 REQUIRES(art::Locks::thread_list_lock_); 137 138 // Returns true if we decoded the thread, false otherwise with an appropriate error placed into 139 // 'err' 140 static bool GetNativeThread(jthread thread, 141 const art::ScopedObjectAccessAlreadyRunnable& soa, 142 /*out*/ art::Thread** thr, 143 /*out*/ jvmtiError* err) 144 REQUIRES_SHARED(art::Locks::mutator_lock_) 145 REQUIRES(art::Locks::thread_list_lock_); 146 147 // Go to sleep if this thread is suspended. 148 static void SuspendCheck(art::Thread* self) 149 REQUIRES(!art::Locks::mutator_lock_, !art::Locks::user_code_suspension_lock_); 150 151 // Returns true if the thread would be suspended if it locks the mutator-lock or calls 152 // SuspendCheck. This function is called with the user_code_suspension_lock already held. 153 static bool WouldSuspendForUserCodeLocked(art::Thread* self) 154 REQUIRES(art::Locks::user_code_suspension_lock_, 155 !art::Locks::thread_suspend_count_lock_); 156 157 // Returns true if this thread would go to sleep if it locks the mutator-lock or calls 158 // SuspendCheck. 159 static bool WouldSuspendForUserCode(art::Thread* self) 160 REQUIRES(!art::Locks::user_code_suspension_lock_, 161 !art::Locks::thread_suspend_count_lock_); 162 163 static JvmtiGlobalTLSData* GetGlobalTLSData(art::Thread* thread) 164 REQUIRES(art::Locks::thread_list_lock_); 165 static JvmtiGlobalTLSData* GetOrCreateGlobalTLSData(art::Thread* thread) 166 REQUIRES(art::Locks::thread_list_lock_); 167 168 private: 169 // We need to make sure only one thread tries to suspend threads at a time so we can get the 170 // 'suspend-only-once' behavior the spec requires. Internally, ART considers suspension to be a 171 // counted state, allowing a single thread to be suspended multiple times by different users. This 172 // makes mapping into the JVMTI idea of thread suspension difficult. We have decided to split the 173 // difference and ensure that JVMTI tries to treat suspension as the boolean flag as much as 174 // possible with the suspend/resume methods but only do best effort. On the other hand 175 // GetThreadState will be totally accurate as much as possible. This means that calling 176 // ResumeThread on a thread that has state JVMTI_THREAD_STATE_SUSPENDED will not necessarily 177 // cause the thread to wake up if the thread is suspended for the debugger or gc or something. 178 static jvmtiError SuspendSelf(art::Thread* self) 179 REQUIRES(!art::Locks::mutator_lock_, !art::Locks::user_code_suspension_lock_); 180 static jvmtiError SuspendOther(art::Thread* self, jthread target_jthread) 181 REQUIRES(!art::Locks::mutator_lock_, !art::Locks::user_code_suspension_lock_); 182 183 static art::ArtField* context_class_loader_; 184 }; 185 186 } // namespace openjdkjvmti 187 188 #endif // ART_OPENJDKJVMTI_TI_THREAD_H_ 189
