1 /* 2 * Copyright (c) 2015, 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 "runtime/threadLocalStorage.hpp" 26 #include <pthread.h> 27 28 static pthread_key_t _thread_key; 29 static bool _initialized = false; 30 31 // Restore the thread pointer if the destructor is called. This is in case 32 // someone from JNI code sets up a destructor with pthread_key_create to run 33 // detachCurrentThread on thread death. Unless we restore the thread pointer we 34 // will hang or crash. When detachCurrentThread is called the key will be set 35 // to null and we will not be called again. If detachCurrentThread is never 36 // called we could loop forever depending on the pthread implementation. 37 extern "C" void restore_thread_pointer(void* p) { 38 ThreadLocalStorage::set_thread((Thread*) p); 39 } 40 41 void ThreadLocalStorage::init() { 42 assert(!_initialized, "initializing TLS more than once!"); 43 int rslt = pthread_key_create(&_thread_key, restore_thread_pointer); 44 // If this assert fails we will get a recursive assertion failure 45 // and not see the actual error message or get a hs_err file 46 assert_status(rslt == 0, rslt, "pthread_key_create"); 47 _initialized = true; 48 } 49 50 bool ThreadLocalStorage::is_initialized() { 51 return _initialized; 52 } 53 54 Thread* ThreadLocalStorage::thread() { 55 // If this assert fails we will get a recursive assertion failure 56 // and not see the actual error message or get a hs_err file. 57 // Which most likely indicates we have taken an error path early in 58 // the initialization process, which is using Thread::current without 59 // checking TLS is initialized - see java.cpp vm_exit 60 assert(_initialized, "TLS not initialized yet!"); 61 return (Thread*) pthread_getspecific(_thread_key); // may be NULL 62 } 63 64 void ThreadLocalStorage::set_thread(Thread* current) { 65 assert(_initialized, "TLS not initialized yet!"); 66 int rslt = pthread_setspecific(_thread_key, current); 67 assert_status(rslt == 0, rslt, "pthread_setspecific"); 68 }