/* $Id: AutoLock.cpp $ */ /** @file * Automatic locks, implementation. */ /* * Copyright (C) 2006-2020 Oracle Corporation * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) as published by the Free Software * Foundation, in version 2 as it comes in the "COPYING" file of the * VirtualBox OSE distribution. VirtualBox OSE is distributed in the * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. */ /********************************************************************************************************************************* * Defined Constants And Macros * *********************************************************************************************************************************/ #define GLUE_USE_CRITSECTRW /********************************************************************************************************************************* * Header Files * *********************************************************************************************************************************/ #include #include #include #include #include #include #if defined(RT_LOCK_STRICT) # include // for ASMReturnAddress #endif #include #include #include #include "VBox/com/AutoLock.h" #include #include #include #include namespace util { //////////////////////////////////////////////////////////////////////////////// // // RuntimeLockClass // //////////////////////////////////////////////////////////////////////////////// #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION typedef std::map LockValidationClassesMap; LockValidationClassesMap g_mapLockValidationClasses; #endif /** * Called from initterm.cpp on process initialization (on the main thread) * to give us a chance to initialize lock validation runtime data. */ void InitAutoLockSystem() { #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION struct { VBoxLockingClass cls; const char *pcszDescription; } aClasses[] = { { LOCKCLASS_VIRTUALBOXOBJECT, "2-VIRTUALBOXOBJECT" }, { LOCKCLASS_HOSTOBJECT, "3-HOSTOBJECT" }, { LOCKCLASS_LISTOFMACHINES, "4-LISTOFMACHINES" }, { LOCKCLASS_MACHINEOBJECT, "5-MACHINEOBJECT" }, { LOCKCLASS_SNAPSHOTOBJECT, "6-SNAPSHOTOBJECT" }, { LOCKCLASS_MEDIUMQUERY, "7-MEDIUMQUERY" }, { LOCKCLASS_LISTOFMEDIA, "8-LISTOFMEDIA" }, { LOCKCLASS_LISTOFOTHEROBJECTS, "9-LISTOFOTHEROBJECTS" }, { LOCKCLASS_OTHEROBJECT, "10-OTHEROBJECT" }, { LOCKCLASS_PROGRESSLIST, "11-PROGRESSLIST" }, { LOCKCLASS_OBJECTSTATE, "12-OBJECTSTATE" } }; RTLOCKVALCLASS hClass; int vrc; for (unsigned i = 0; i < RT_ELEMENTS(aClasses); ++i) { vrc = RTLockValidatorClassCreate(&hClass, true, /*fAutodidact*/ RT_SRC_POS, aClasses[i].pcszDescription); AssertRC(vrc); // teach the new class that the classes created previously can be held // while the new class is being acquired for (LockValidationClassesMap::iterator it = g_mapLockValidationClasses.begin(); it != g_mapLockValidationClasses.end(); ++it) { RTLOCKVALCLASS &canBeHeld = it->second; vrc = RTLockValidatorClassAddPriorClass(hClass, canBeHeld); AssertRC(vrc); } // and store the new class g_mapLockValidationClasses[aClasses[i].cls] = hClass; } /* WriteLockHandle critsect1(LOCKCLASS_VIRTUALBOXOBJECT); WriteLockHandle critsect2(LOCKCLASS_VIRTUALBOXLIST); AutoWriteLock lock1(critsect1 COMMA_LOCKVAL_SRC_POS); AutoWriteLock lock2(critsect2 COMMA_LOCKVAL_SRC_POS);*/ #endif } bool AutoLockHoldsLocksInClass(VBoxLockingClass lockClass) { #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION return RTLockValidatorHoldsLocksInClass(NIL_RTTHREAD, g_mapLockValidationClasses[lockClass]); #else RT_NOREF(lockClass); return false; #endif } //////////////////////////////////////////////////////////////////////////////// // // RWLockHandle // //////////////////////////////////////////////////////////////////////////////// struct RWLockHandle::Data { Data() { } #ifdef GLUE_USE_CRITSECTRW mutable RTCRITSECTRW CritSect; #else RTSEMRW sem; #endif VBoxLockingClass lockClass; #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION com::Utf8Str strDescription; #endif }; RWLockHandle::RWLockHandle(VBoxLockingClass lockClass) { m = new Data(); m->lockClass = lockClass; #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION m->strDescription = com::Utf8StrFmt("r/w %RCv", this); #endif #ifdef GLUE_USE_CRITSECTRW # ifdef VBOX_WITH_MAIN_LOCK_VALIDATION int vrc = RTCritSectRwInitEx(&m->CritSect, 0 /*fFlags*/, g_mapLockValidationClasses[lockClass], RTLOCKVAL_SUB_CLASS_ANY, NULL); # else int vrc = RTCritSectRwInitEx(&m->CritSect, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_ANY, NULL); # endif #else # ifdef VBOX_WITH_MAIN_LOCK_VALIDATION int vrc = RTSemRWCreateEx(&m->sem, 0 /*fFlags*/, g_mapLockValidationClasses[lockClass], RTLOCKVAL_SUB_CLASS_ANY, NULL); # else int vrc = RTSemRWCreateEx(&m->sem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_ANY, NULL); # endif #endif AssertRC(vrc); } /*virtual*/ RWLockHandle::~RWLockHandle() { #ifdef GLUE_USE_CRITSECTRW RTCritSectRwDelete(&m->CritSect); #else RTSemRWDestroy(m->sem); #endif delete m; } /*virtual*/ bool RWLockHandle::isWriteLockOnCurrentThread() const { #ifdef GLUE_USE_CRITSECTRW return RTCritSectRwIsWriteOwner(&m->CritSect); #else return RTSemRWIsWriteOwner(m->sem); #endif } /*virtual*/ void RWLockHandle::lockWrite(LOCKVAL_SRC_POS_DECL) { #ifdef GLUE_USE_CRITSECTRW # ifdef VBOX_WITH_MAIN_LOCK_VALIDATION int vrc = RTCritSectRwEnterExclDebug(&m->CritSect, (uintptr_t)ASMReturnAddress(), RT_SRC_POS_ARGS); # else int vrc = RTCritSectRwEnterExcl(&m->CritSect); # endif #else # ifdef VBOX_WITH_MAIN_LOCK_VALIDATION int vrc = RTSemRWRequestWriteDebug(m->sem, RT_INDEFINITE_WAIT, (uintptr_t)ASMReturnAddress(), RT_SRC_POS_ARGS); # else int vrc = RTSemRWRequestWrite(m->sem, RT_INDEFINITE_WAIT); # endif #endif AssertRC(vrc); } /*virtual*/ void RWLockHandle::unlockWrite() { #ifdef GLUE_USE_CRITSECTRW int vrc = RTCritSectRwLeaveExcl(&m->CritSect); #else int vrc = RTSemRWReleaseWrite(m->sem); #endif AssertRC(vrc); } /*virtual*/ bool RWLockHandle::isReadLockedOnCurrentThread(bool fWannaHear) const { #ifdef GLUE_USE_CRITSECTRW return RTCritSectRwIsReadOwner(&m->CritSect, fWannaHear); #else return RTSemRWIsReadOwner(m->sem, fWannaHear); #endif } /*virtual*/ void RWLockHandle::lockRead(LOCKVAL_SRC_POS_DECL) { #ifdef GLUE_USE_CRITSECTRW # ifdef VBOX_WITH_MAIN_LOCK_VALIDATION int vrc = RTCritSectRwEnterSharedDebug(&m->CritSect, (uintptr_t)ASMReturnAddress(), RT_SRC_POS_ARGS); # else int vrc = RTCritSectRwEnterShared(&m->CritSect); # endif #else # ifdef VBOX_WITH_MAIN_LOCK_VALIDATION int vrc = RTSemRWRequestReadDebug(m->sem, RT_INDEFINITE_WAIT, (uintptr_t)ASMReturnAddress(), RT_SRC_POS_ARGS); # else int vrc = RTSemRWRequestRead(m->sem, RT_INDEFINITE_WAIT); # endif #endif AssertRC(vrc); } /*virtual*/ void RWLockHandle::unlockRead() { #ifdef GLUE_USE_CRITSECTRW int vrc = RTCritSectRwLeaveShared(&m->CritSect); #else int vrc = RTSemRWReleaseRead(m->sem); #endif AssertRC(vrc); } /*virtual*/ uint32_t RWLockHandle::writeLockLevel() const { /* Note! This does not include read recursions done by the writer! */ #ifdef GLUE_USE_CRITSECTRW return RTCritSectRwGetWriteRecursion(&m->CritSect); #else return RTSemRWGetWriteRecursion(m->sem); #endif } #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION /*virtual*/ const char* RWLockHandle::describe() const { return m->strDescription.c_str(); } #endif //////////////////////////////////////////////////////////////////////////////// // // WriteLockHandle // //////////////////////////////////////////////////////////////////////////////// struct WriteLockHandle::Data { Data() { } mutable RTCRITSECT sem; VBoxLockingClass lockClass; #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION com::Utf8Str strDescription; #endif }; WriteLockHandle::WriteLockHandle(VBoxLockingClass lockClass) { m = new Data; m->lockClass = lockClass; #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION m->strDescription = com::Utf8StrFmt("crit %RCv", this); int vrc = RTCritSectInitEx(&m->sem, 0/*fFlags*/, g_mapLockValidationClasses[lockClass], RTLOCKVAL_SUB_CLASS_ANY, NULL); #else int vrc = RTCritSectInitEx(&m->sem, 0/*fFlags*/, NIL_RTLOCKVALCLASS, RTLOCKVAL_SUB_CLASS_ANY, NULL); #endif AssertRC(vrc); } WriteLockHandle::~WriteLockHandle() { RTCritSectDelete(&m->sem); delete m; } /*virtual*/ bool WriteLockHandle::isWriteLockOnCurrentThread() const { return RTCritSectIsOwner(&m->sem); } /*virtual*/ void WriteLockHandle::lockWrite(LOCKVAL_SRC_POS_DECL) { #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION RTCritSectEnterDebug(&m->sem, (uintptr_t)ASMReturnAddress(), RT_SRC_POS_ARGS); #else RTCritSectEnter(&m->sem); #endif } /*virtual*/ bool WriteLockHandle::isReadLockedOnCurrentThread(bool fWannaHear) const { RT_NOREF(fWannaHear); return RTCritSectIsOwner(&m->sem); } /*virtual*/ void WriteLockHandle::unlockWrite() { RTCritSectLeave(&m->sem); } /*virtual*/ void WriteLockHandle::lockRead(LOCKVAL_SRC_POS_DECL) { lockWrite(LOCKVAL_SRC_POS_ARGS); } /*virtual*/ void WriteLockHandle::unlockRead() { unlockWrite(); } /*virtual*/ uint32_t WriteLockHandle::writeLockLevel() const { return RTCritSectGetRecursion(&m->sem); } #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION /*virtual*/ const char* WriteLockHandle::describe() const { return m->strDescription.c_str(); } #endif //////////////////////////////////////////////////////////////////////////////// // // AutoLockBase // //////////////////////////////////////////////////////////////////////////////// typedef std::vector HandlesVector; struct AutoLockBase::Data { Data(size_t cHandles #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION , const char *pcszFile_, unsigned uLine_, const char *pcszFunction_ #endif ) : fIsLocked(false), aHandles(cHandles) // size of array #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION , pcszFile(pcszFile_), uLine(uLine_), pcszFunction(pcszFunction_) #endif { for (uint32_t i = 0; i < cHandles; ++i) aHandles[i] = NULL; } bool fIsLocked; // if true, then all items in aHandles are locked by this AutoLock and // need to be unlocked in the destructor HandlesVector aHandles; // array (vector) of LockHandle instances; in the case of AutoWriteLock // and AutoReadLock, there will only be one item on the list; with the // AutoMulti* derivatives, there will be multiple #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION // information about where the lock occurred (passed down from the AutoLock classes) const char *pcszFile; unsigned uLine; const char *pcszFunction; #endif }; AutoLockBase::AutoLockBase(uint32_t cHandles COMMA_LOCKVAL_SRC_POS_DECL) { m = new Data(cHandles COMMA_LOCKVAL_SRC_POS_ARGS); } AutoLockBase::AutoLockBase(uint32_t cHandles, LockHandle *pHandle COMMA_LOCKVAL_SRC_POS_DECL) { Assert(cHandles == 1); NOREF(cHandles); m = new Data(1 COMMA_LOCKVAL_SRC_POS_ARGS); m->aHandles[0] = pHandle; } AutoLockBase::~AutoLockBase() { delete m; } /** * Requests ownership of all contained lock handles by calling * the pure virtual callLockImpl() function on each of them, * which must be implemented by the descendant class; in the * implementation, AutoWriteLock will request a write lock * whereas AutoReadLock will request a read lock. * * Does *not* modify the lock counts in the member variables. */ void AutoLockBase::callLockOnAllHandles() { for (HandlesVector::iterator it = m->aHandles.begin(); it != m->aHandles.end(); ++it) { LockHandle *pHandle = *it; if (pHandle) // call virtual function implemented in AutoWriteLock or AutoReadLock this->callLockImpl(*pHandle); } } /** * Releases ownership of all contained lock handles by calling * the pure virtual callUnlockImpl() function on each of them, * which must be implemented by the descendant class; in the * implementation, AutoWriteLock will release a write lock * whereas AutoReadLock will release a read lock. * * Does *not* modify the lock counts in the member variables. */ void AutoLockBase::callUnlockOnAllHandles() { // unlock in reverse order! for (HandlesVector::reverse_iterator it = m->aHandles.rbegin(); it != m->aHandles.rend(); ++it) { LockHandle *pHandle = *it; if (pHandle) // call virtual function implemented in AutoWriteLock or AutoReadLock this->callUnlockImpl(*pHandle); } } /** * Destructor implementation that can also be called explicitly, if required. * Restores the exact state before the AutoLock was created; that is, unlocks * all contained semaphores. */ void AutoLockBase::cleanup() { if (m->fIsLocked) callUnlockOnAllHandles(); } /** * Requests ownership of all contained semaphores. Public method that can * only be called once and that also gets called by the AutoLock constructors. */ void AutoLockBase::acquire() { AssertMsgReturnVoid(!m->fIsLocked, ("m->fIsLocked is true, attempting to lock twice!")); callLockOnAllHandles(); m->fIsLocked = true; } /** * Releases ownership of all contained semaphores. Public method. */ void AutoLockBase::release() { AssertMsgReturnVoid(m->fIsLocked, ("m->fIsLocked is false, cannot release!")); callUnlockOnAllHandles(); m->fIsLocked = false; } //////////////////////////////////////////////////////////////////////////////// // // AutoReadLock // //////////////////////////////////////////////////////////////////////////////// /** * Release all read locks acquired by this instance through the #lock() * call and destroys the instance. * * Note that if there there are nested #lock() calls without the * corresponding number of #unlock() calls when the destructor is called, it * will assert. This is because having an unbalanced number of nested locks * is a program logic error which must be fixed. */ /*virtual*/ AutoReadLock::~AutoReadLock() { LockHandle *pHandle = m->aHandles[0]; if (pHandle) { if (m->fIsLocked) callUnlockImpl(*pHandle); } } /** * Implementation of the pure virtual declared in AutoLockBase. * This gets called by AutoLockBase.acquire() to actually request * the semaphore; in the AutoReadLock implementation, we request * the semaphore in read mode. */ /*virtual*/ void AutoReadLock::callLockImpl(LockHandle &l) { #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION l.lockRead(m->pcszFile, m->uLine, m->pcszFunction); #else l.lockRead(); #endif } /** * Implementation of the pure virtual declared in AutoLockBase. * This gets called by AutoLockBase.release() to actually release * the semaphore; in the AutoReadLock implementation, we release * the semaphore in read mode. */ /*virtual*/ void AutoReadLock::callUnlockImpl(LockHandle &l) { l.unlockRead(); } //////////////////////////////////////////////////////////////////////////////// // // AutoWriteLockBase // //////////////////////////////////////////////////////////////////////////////// /** * Implementation of the pure virtual declared in AutoLockBase. * This gets called by AutoLockBase.acquire() to actually request * the semaphore; in the AutoWriteLock implementation, we request * the semaphore in write mode. */ /*virtual*/ void AutoWriteLockBase::callLockImpl(LockHandle &l) { #ifdef VBOX_WITH_MAIN_LOCK_VALIDATION l.lockWrite(m->pcszFile, m->uLine, m->pcszFunction); #else l.lockWrite(); #endif } /** * Implementation of the pure virtual declared in AutoLockBase. * This gets called by AutoLockBase.release() to actually release * the semaphore; in the AutoWriteLock implementation, we release * the semaphore in write mode. */ /*virtual*/ void AutoWriteLockBase::callUnlockImpl(LockHandle &l) { l.unlockWrite(); } //////////////////////////////////////////////////////////////////////////////// // // AutoWriteLock // //////////////////////////////////////////////////////////////////////////////// AutoWriteLock::AutoWriteLock(uint32_t cHandles, LockHandle** pHandles COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(cHandles COMMA_LOCKVAL_SRC_POS_ARGS) { Assert(cHandles); Assert(pHandles); for (uint32_t i = 0; i < cHandles; ++i) m->aHandles[i] = pHandles[i]; acquire(); } /** * Attaches another handle to this auto lock instance. * * The previous object's lock is completely released before the new one is * acquired. The lock level of the new handle will be the same. This * also means that if the lock was not acquired at all before #attach(), it * will not be acquired on the new handle too. * * @param aHandle New handle to attach. */ void AutoWriteLock::attach(LockHandle *aHandle) { LockHandle *pHandle = m->aHandles[0]; /* detect simple self-reattachment */ if (pHandle != aHandle) { bool fWasLocked = m->fIsLocked; cleanup(); m->aHandles[0] = aHandle; m->fIsLocked = fWasLocked; if (aHandle) if (fWasLocked) callLockImpl(*aHandle); } } /** * Returns @c true if the current thread holds a write lock on the managed * read/write semaphore. Returns @c false if the managed semaphore is @c * NULL. * * @note Intended for debugging only. */ bool AutoWriteLock::isWriteLockOnCurrentThread() const { return m->aHandles[0] ? m->aHandles[0]->isWriteLockOnCurrentThread() : false; } /** * Returns the current write lock level of the managed semaphore. The lock * level determines the number of nested #lock() calls on the given * semaphore handle. Returns @c 0 if the managed semaphore is @c * NULL. * * Note that this call is valid only when the current thread owns a write * lock on the given semaphore handle and will assert otherwise. * * @note Intended for debugging only. */ uint32_t AutoWriteLock::writeLockLevel() const { return m->aHandles[0] ? m->aHandles[0]->writeLockLevel() : 0; } /** * Returns @c true if the current thread holds a write lock on the managed * read/write semaphore. Returns @c false if the managed semaphore is @c * NULL. * * @note Intended for debugging only (esp. considering fWannaHear). */ bool AutoWriteLock::isReadLockedOnCurrentThread(bool fWannaHear) const { return m->aHandles[0] ? m->aHandles[0]->isReadLockedOnCurrentThread(fWannaHear) : false; } //////////////////////////////////////////////////////////////////////////////// // // AutoMultiWriteLock* // //////////////////////////////////////////////////////////////////////////////// AutoMultiWriteLock2::AutoMultiWriteLock2(Lockable *pl1, Lockable *pl2 COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(2 COMMA_LOCKVAL_SRC_POS_ARGS) { if (pl1) m->aHandles[0] = pl1->lockHandle(); if (pl2) m->aHandles[1] = pl2->lockHandle(); acquire(); } AutoMultiWriteLock2::AutoMultiWriteLock2(LockHandle *pl1, LockHandle *pl2 COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(2 COMMA_LOCKVAL_SRC_POS_ARGS) { m->aHandles[0] = pl1; m->aHandles[1] = pl2; acquire(); } AutoMultiWriteLock3::AutoMultiWriteLock3(Lockable *pl1, Lockable *pl2, Lockable *pl3 COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(3 COMMA_LOCKVAL_SRC_POS_ARGS) { if (pl1) m->aHandles[0] = pl1->lockHandle(); if (pl2) m->aHandles[1] = pl2->lockHandle(); if (pl3) m->aHandles[2] = pl3->lockHandle(); acquire(); } AutoMultiWriteLock3::AutoMultiWriteLock3(LockHandle *pl1, LockHandle *pl2, LockHandle *pl3 COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(3 COMMA_LOCKVAL_SRC_POS_ARGS) { m->aHandles[0] = pl1; m->aHandles[1] = pl2; m->aHandles[2] = pl3; acquire(); } AutoMultiWriteLock4::AutoMultiWriteLock4(Lockable *pl1, Lockable *pl2, Lockable *pl3, Lockable *pl4 COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(4 COMMA_LOCKVAL_SRC_POS_ARGS) { if (pl1) m->aHandles[0] = pl1->lockHandle(); if (pl2) m->aHandles[1] = pl2->lockHandle(); if (pl3) m->aHandles[2] = pl3->lockHandle(); if (pl4) m->aHandles[3] = pl4->lockHandle(); acquire(); } AutoMultiWriteLock4::AutoMultiWriteLock4(LockHandle *pl1, LockHandle *pl2, LockHandle *pl3, LockHandle *pl4 COMMA_LOCKVAL_SRC_POS_DECL) : AutoWriteLockBase(4 COMMA_LOCKVAL_SRC_POS_ARGS) { m->aHandles[0] = pl1; m->aHandles[1] = pl2; m->aHandles[2] = pl3; m->aHandles[3] = pl4; acquire(); } } /* namespace util */ /* vi: set tabstop=4 shiftwidth=4 expandtab: */