granicus.if.org Git - icinga2/blob - lib/base/objectlock.cpp

   1 /******************************************************************************
   2  * Icinga 2                                                                   *
   3  * Copyright (C) 2012-2018 Icinga Development Team (https://www.icinga.com/)  *
   4  *                                                                            *
   5  * This program is free software; you can redistribute it and/or              *
   6  * modify it under the terms of the GNU General Public License                *
   7  * as published by the Free Software Foundation; either version 2             *
   8  * of the License, or (at your option) any later version.                     *
   9  *                                                                            *
  10  * This program is distributed in the hope that it will be useful,            *
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of             *
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              *
  13  * GNU General Public License for more details.                               *
  14  *                                                                            *
  15  * You should have received a copy of the GNU General Public License          *
  16  * along with this program; if not, write to the Free Software Foundation     *
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
  18  ******************************************************************************/
  19
  20 #include "base/objectlock.hpp"
  21 #include <boost/thread/recursive_mutex.hpp>
  22
  23 using namespace icinga;
  24
  25 #define I2MUTEX_UNLOCKED 0
  26 #define I2MUTEX_LOCKED 1
  27
  28 ObjectLock::~ObjectLock()
  29 {
  30         Unlock();
  31 }
  32
  33 ObjectLock::ObjectLock(const Object::Ptr& object)
  34         : m_Object(object.get()), m_Locked(false)
  35 {
  36         if (m_Object)
  37                 Lock();
  38 }
  39
  40 ObjectLock::ObjectLock(const Object *object)
  41         : m_Object(object), m_Locked(false)
  42 {
  43         if (m_Object)
  44                 Lock();
  45 }
  46
  47 void ObjectLock::LockMutex(const Object *object)
  48 {
  49         unsigned int it = 0;
  50
  51 #ifdef _WIN32
  52 #       ifdef _WIN64
  53         while (likely(InterlockedCompareExchange64((LONGLONG *)&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED)) {
  54 #       else /* _WIN64 */
  55         while (likely(InterlockedCompareExchange(&object->m_Mutex, I2MUTEX_LOCKED, I2MUTEX_UNLOCKED) != I2MUTEX_UNLOCKED)) {
  56 #       endif /* _WIN64 */
  57 #else /* _WIN32 */
  58         while (likely(!__sync_bool_compare_and_swap(&object->m_Mutex, I2MUTEX_UNLOCKED, I2MUTEX_LOCKED))) {
  59 #endif /* _WIN32 */
  60                 if (likely(object->m_Mutex > I2MUTEX_LOCKED)) {
  61                         auto *mtx = reinterpret_cast<boost::recursive_mutex *>(object->m_Mutex);
  62                         mtx->lock();
  63
  64                         return;
  65                 }
  66
  67                 Spin(it);
  68                 it++;
  69         }
  70
  71         auto *mtx = new boost::recursive_mutex();
  72         mtx->lock();
  73 #ifdef _WIN32
  74 #       ifdef _WIN64
  75         InterlockedCompareExchange64((LONGLONG *)&object->m_Mutex, reinterpret_cast<LONGLONG>(mtx), I2MUTEX_LOCKED);
  76 #       else /* _WIN64 */
  77         InterlockedCompareExchange(&object->m_Mutex, reinterpret_cast<LONG>(mtx), I2MUTEX_LOCKED);
  78 #       endif /* _WIN64 */
  79 #else /* _WIN32 */
  80         __sync_bool_compare_and_swap(&object->m_Mutex, I2MUTEX_LOCKED, reinterpret_cast<uintptr_t>(mtx));
  81 #endif /* _WIN32 */
  82 }
  83
  84 void ObjectLock::Lock()
  85 {
  86         ASSERT(!m_Locked && m_Object);
  87
  88         LockMutex(m_Object);
  89
  90         m_Locked = true;
  91
  92 #ifdef I2_DEBUG
  93 #       ifdef _WIN32
  94         InterlockedExchange(&m_Object->m_LockOwner, GetCurrentThreadId());
  95 #       else /* _WIN32 */
  96         __sync_lock_test_and_set(&m_Object->m_LockOwner, pthread_self());
  97 #       endif /* _WIN32 */
  98 #endif /* I2_DEBUG */
  99 }
 100
 101 void ObjectLock::Spin(unsigned int it)
 102 {
 103         if (it < 8) {
 104                 /* Do nothing. */
 105         }
 106 #ifdef SPIN_PAUSE
 107         else if (it < 16) {
 108                 SPIN_PAUSE();
 109         }
 110 #endif /* SPIN_PAUSE */
 111         else {
 112 #ifdef _WIN32
 113                 Sleep(0);
 114 #else /* _WIN32 */
 115                 sched_yield();
 116 #endif /* _WIN32 */
 117         }
 118 }
 119
 120 void ObjectLock::Unlock()
 121 {
 122 #ifdef I2_DEBUG
 123         if (m_Locked) {
 124 #       ifdef _WIN32
 125                 InterlockedExchange(&m_Object->m_LockOwner, 0);
 126 #       else /* _WIN32 */
 127                 __sync_lock_release(&m_Object->m_LockOwner);
 128 #       endif /* _WIN32 */
 129         }
 130 #endif /* I2_DEBUG */
 131
 132         if (m_Locked) {
 133                 reinterpret_cast<boost::recursive_mutex *>(m_Object->m_Mutex)->unlock();
 134                 m_Locked = false;
 135         }
 136 }