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Diffstat (limited to 'include/iprt/critsect.h')
| -rw-r--r-- | include/iprt/critsect.h | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/include/iprt/critsect.h b/include/iprt/critsect.h new file mode 100644 index 00000000..41bb65bd --- /dev/null +++ b/include/iprt/critsect.h @@ -0,0 +1,366 @@ +/** @file + * IPRT - Critical Sections. + */ + +/* + * Copyright (C) 2006-2011 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. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL) only, as it comes in the "COPYING.CDDL" file of the + * VirtualBox OSE distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + */ + +#ifndef ___iprt_critsect_h +#define ___iprt_critsect_h + +#include <iprt/cdefs.h> +#include <iprt/types.h> +#include <iprt/assert.h> +#ifdef IN_RING3 +# include <iprt/thread.h> +#endif +#ifdef RT_LOCK_STRICT_ORDER +# include <iprt/lockvalidator.h> +#endif + +RT_C_DECLS_BEGIN + +/** @defgroup grp_rt_critsect RTCritSect - Critical Sections + * + * "Critical section" synchronization primitives can be used to + * protect a section of code or data to which access must be exclusive; + * only one thread can hold access to a critical section at one time. + * + * A critical section is a fast recursive write lock; if the critical + * section is not acquired, then entering it is fast (requires no system + * call). IPRT uses the Windows terminology here; on other platform, this + * might be called a "futex" or a "fast mutex". As opposed to IPRT + * "fast mutexes" (see @ref grp_rt_sems_fast_mutex ), critical sections + * are recursive. + * + * Use RTCritSectInit to initialize a critical section; use RTCritSectEnter + * and RTCritSectLeave to acquire and release access. + * + * For an overview of all types of synchronization primitives provided + * by IPRT (event, mutex/fast mutex/read-write mutex semaphores), see + * @ref grp_rt_sems . + * + * @ingroup grp_rt + * @{ + */ + +/** + * Critical section. + */ +typedef struct RTCRITSECT +{ + /** Magic used to validate the section state. + * RTCRITSECT_MAGIC is the value of an initialized & operational section. */ + volatile uint32_t u32Magic; + /** Number of lockers. + * -1 if the section is free. */ + volatile int32_t cLockers; + /** The owner thread. */ + volatile RTNATIVETHREAD NativeThreadOwner; + /** Number of nested enter operations performed. + * Greater or equal to 1 if owned, 0 when free. + */ + volatile int32_t cNestings; + /** Section flags - the RTCRITSECT_FLAGS_* \#defines. */ + uint32_t fFlags; + /** The semaphore to block on. */ + RTSEMEVENT EventSem; + /** Lock validator record. Only used in strict builds. */ + R3R0PTRTYPE(PRTLOCKVALRECEXCL) pValidatorRec; + /** Alignmnet padding. */ + RTHCPTR Alignment; +} RTCRITSECT; +AssertCompileSize(RTCRITSECT, HC_ARCH_BITS == 32 ? 32 : 48); + +/** RTCRITSECT::u32Magic value. (Hiromi Uehara) */ +#define RTCRITSECT_MAGIC UINT32_C(0x19790326) + +/** @name RTCritSectInitEx flags / RTCRITSECT::fFlags + * @{ */ +/** If set, nesting(/recursion) is not allowed. */ +#define RTCRITSECT_FLAGS_NO_NESTING UINT32_C(0x00000001) +/** Disables lock validation. */ +#define RTCRITSECT_FLAGS_NO_LOCK_VAL UINT32_C(0x00000002) +/** Bootstrap hack for use with certain memory allocator locks only! */ +#define RTCRITSECT_FLAGS_BOOTSTRAP_HACK UINT32_C(0x00000004) +/** If set, the critical section becomes a dummy that doesn't serialize any + * threads. This flag can only be set at creation time. + * + * The intended use is avoiding lots of conditional code where some component + * might or might not require entering a critical section before access. */ +#define RTCRITSECT_FLAGS_NOP UINT32_C(0x00000008) +/** @} */ + +#ifdef IN_RING3 + +/** + * Initialize a critical section. + */ +RTDECL(int) RTCritSectInit(PRTCRITSECT pCritSect); + +/** + * Initialize a critical section. + * + * @returns iprt status code. + * @param pCritSect Pointer to the critical section structure. + * @param fFlags Flags, any combination of the RTCRITSECT_FLAGS + * \#defines. + * @param hClass The class (no reference consumed). If NIL, no + * lock order validation will be performed on this + * lock. + * @param uSubClass The sub-class. This is used to define lock + * order within a class. RTLOCKVAL_SUB_CLASS_NONE + * is the recommended value here. + * @param pszNameFmt Name format string for the lock validator, + * optional (NULL). Max length is 32 bytes. + * @param ... Format string arguments. + */ +RTDECL(int) RTCritSectInitEx(PRTCRITSECT pCritSect, uint32_t fFlags, + RTLOCKVALCLASS hClass, uint32_t uSubClass, const char *pszNameFmt, ...); + +/** + * Changes the lock validator sub-class of the critical section. + * + * It is recommended to try make sure that nobody is using this critical section + * while changing the value. + * + * @returns The old sub-class. RTLOCKVAL_SUB_CLASS_INVALID is returns if the + * lock validator isn't compiled in or either of the parameters are + * invalid. + * @param pCritSect The critical section. + * @param uSubClass The new sub-class value. + */ +RTDECL(uint32_t) RTCritSectSetSubClass(PRTCRITSECT pCritSect, uint32_t uSubClass); + +/** + * Enter a critical section. + * + * @returns VINF_SUCCESS on success. + * @returns VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.) + * @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. + * @param pCritSect The critical section. + */ +RTDECL(int) RTCritSectEnter(PRTCRITSECT pCritSect); + +/** + * Enter a critical section. + * + * @retval VINF_SUCCESS on success. + * @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.) + * @retval VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. + * + * @param pCritSect The critical section. + * @param uId Where we're entering the section. + * @param pszFile The source position - file. + * @param iLine The source position - line. + * @param pszFunction The source position - function. + */ +RTDECL(int) RTCritSectEnterDebug(PRTCRITSECT pCritSect, RTHCUINTPTR uId, RT_SRC_POS_DECL); + +/** + * Try enter a critical section. + * + * @retval VINF_SUCCESS on success. + * @retval VERR_SEM_BUSY if the critsect was owned. + * @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.) + * @retval VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. + * + * @param pCritSect The critical section. + */ +RTDECL(int) RTCritSectTryEnter(PRTCRITSECT pCritSect); + +/** + * Try enter a critical section. + * + * @retval VINF_SUCCESS on success. + * @retval VERR_SEM_BUSY if the critsect was owned. + * @retval VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.) + * @retval VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. + * + * @param pCritSect The critical section. + * @param uId Where we're entering the section. + * @param pszFile The source position - file. + * @param iLine The source position - line. + * @param pszFunction The source position - function. + */ +RTDECL(int) RTCritSectTryEnterDebug(PRTCRITSECT pCritSect, RTHCUINTPTR uId, RT_SRC_POS_DECL); + +/** + * Enter multiple critical sections. + * + * This function will enter ALL the specified critical sections before returning. + * + * @returns VINF_SUCCESS on success. + * @returns VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.) + * @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. + * @param cCritSects Number of critical sections in the array. + * @param papCritSects Array of critical section pointers. + * + * @remark Please note that this function will not necessarily come out favourable in a + * fight with other threads which are using the normal RTCritSectEnter() function. + * Therefore, avoid having to enter multiple critical sections! + */ +RTDECL(int) RTCritSectEnterMultiple(size_t cCritSects, PRTCRITSECT *papCritSects); + +/** + * Enter multiple critical sections. + * + * This function will enter ALL the specified critical sections before returning. + * + * @returns VINF_SUCCESS on success. + * @returns VERR_SEM_NESTED if nested enter on a no nesting section. (Asserted.) + * @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting. + * + * @param cCritSects Number of critical sections in the array. + * @param papCritSects Array of critical section pointers. + * @param uId Where we're entering the section. + * @param pszFile The source position - file. + * @param iLine The source position - line. + * @param pszFunction The source position - function. + * + * @remark See RTCritSectEnterMultiple(). + */ +RTDECL(int) RTCritSectEnterMultipleDebug(size_t cCritSects, PRTCRITSECT *papCritSects, RTUINTPTR uId, RT_SRC_POS_DECL); + +/** + * Leave a critical section. + * + * @returns VINF_SUCCESS. + * @param pCritSect The critical section. + */ +RTDECL(int) RTCritSectLeave(PRTCRITSECT pCritSect); + +/** + * Leave multiple critical sections. + * + * @returns VINF_SUCCESS. + * @param cCritSects Number of critical sections in the array. + * @param papCritSects Array of critical section pointers. + */ +RTDECL(int) RTCritSectLeaveMultiple(size_t cCritSects, PRTCRITSECT *papCritSects); + +/** + * Deletes a critical section. + * + * @returns VINF_SUCCESS. + * @param pCritSect The critical section. + */ +RTDECL(int) RTCritSectDelete(PRTCRITSECT pCritSect); + +/** + * Checks the caller is the owner of the critical section. + * + * @returns true if owner. + * @returns false if not owner. + * @param pCritSect The critical section. + */ +DECLINLINE(bool) RTCritSectIsOwner(PCRTCRITSECT pCritSect) +{ + return pCritSect->NativeThreadOwner == RTThreadNativeSelf(); +} + +#endif /* IN_RING3 */ + +/** + * Checks the section is owned by anyone. + * + * @returns true if owned. + * @returns false if not owned. + * @param pCritSect The critical section. + */ +DECLINLINE(bool) RTCritSectIsOwned(PCRTCRITSECT pCritSect) +{ + return pCritSect->NativeThreadOwner != NIL_RTNATIVETHREAD; +} + +/** + * Gets the thread id of the critical section owner. + * + * @returns Thread id of the owner thread if owned. + * @returns NIL_RTNATIVETHREAD is not owned. + * @param pCritSect The critical section. + */ +DECLINLINE(RTNATIVETHREAD) RTCritSectGetOwner(PCRTCRITSECT pCritSect) +{ + return pCritSect->NativeThreadOwner; +} + +/** + * Checks if a critical section is initialized or not. + * + * @returns true if initialized. + * @returns false if not initialized. + * @param pCritSect The critical section. + */ +DECLINLINE(bool) RTCritSectIsInitialized(PCRTCRITSECT pCritSect) +{ + return pCritSect->u32Magic == RTCRITSECT_MAGIC; +} + +/** + * Gets the recursion depth. + * + * @returns The recursion depth. + * @param pCritSect The Critical section + */ +DECLINLINE(uint32_t) RTCritSectGetRecursion(PCRTCRITSECT pCritSect) +{ + return pCritSect->cNestings; +} + +/** + * Gets the waiter count + * + * @returns The waiter count + * @param pCritSect The Critical section + */ +DECLINLINE(int32_t) RTCritSectGetWaiters(PCRTCRITSECT pCritSect) +{ + return pCritSect->cLockers; +} + +/* Lock strict build: Remap the three enter calls to the debug versions. */ +#if defined(RT_LOCK_STRICT) && !defined(RTCRITSECT_WITHOUT_REMAPPING) && !defined(RT_WITH_MANGLING) +# ifdef ___iprt_asm_h +# define RTCritSectEnter(pCritSect) RTCritSectEnterDebug(pCritSect, (uintptr_t)ASMReturnAddress(), RT_SRC_POS) +# define RTCritSectTryEnter(pCritSect) RTCritSectTryEnterDebug(pCritSect, (uintptr_t)ASMReturnAddress(), RT_SRC_POS) +# define RTCritSectEnterMultiple(cCritSects, pCritSect) RTCritSectEnterMultipleDebug((cCritSects), (pCritSect), (uintptr_t)ASMReturnAddress(), RT_SRC_POS) +# else +# define RTCritSectEnter(pCritSect) RTCritSectEnterDebug(pCritSect, 0, RT_SRC_POS) +# define RTCritSectTryEnter(pCritSect) RTCritSectTryEnterDebug(pCritSect, 0, RT_SRC_POS) +# define RTCritSectEnterMultiple(cCritSects, pCritSect) RTCritSectEnterMultipleDebug((cCritSects), (pCritSect), 0, RT_SRC_POS) +# endif +#endif + +/* Strict lock order: Automatically classify locks by init location. */ +#if defined(RT_LOCK_STRICT_ORDER) && defined(IN_RING3) && !defined(RTCRITSECT_WITHOUT_REMAPPING) &&!defined(RT_WITH_MANGLING) +# define RTCritSectInit(pCritSect) \ + RTCritSectInitEx((pCritSect), 0 /*fFlags*/, \ + RTLockValidatorClassForSrcPos(RT_SRC_POS, NULL), \ + RTLOCKVAL_SUB_CLASS_NONE, NULL) +#endif + +/** @} */ + +RT_C_DECLS_END + +#endif + |