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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 17:28:19 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 17:28:19 +0000 |
commit | 18657a960e125336f704ea058e25c27bd3900dcb (patch) | |
tree | 17b438b680ed45a996d7b59951e6aa34023783f2 /src/mutex.c | |
parent | Initial commit. (diff) | |
download | sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.tar.xz sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.zip |
Adding upstream version 3.40.1.upstream/3.40.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/mutex.c | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/src/mutex.c b/src/mutex.c new file mode 100644 index 0000000..13a9fca --- /dev/null +++ b/src/mutex.c @@ -0,0 +1,361 @@ +/* +** 2007 August 14 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** This file contains the C functions that implement mutexes. +** +** This file contains code that is common across all mutex implementations. +*/ +#include "sqliteInt.h" + +#if defined(SQLITE_DEBUG) && !defined(SQLITE_MUTEX_OMIT) +/* +** For debugging purposes, record when the mutex subsystem is initialized +** and uninitialized so that we can assert() if there is an attempt to +** allocate a mutex while the system is uninitialized. +*/ +static SQLITE_WSD int mutexIsInit = 0; +#endif /* SQLITE_DEBUG && !defined(SQLITE_MUTEX_OMIT) */ + + +#ifndef SQLITE_MUTEX_OMIT + +#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS +/* +** This block (enclosed by SQLITE_ENABLE_MULTITHREADED_CHECKS) contains +** the implementation of a wrapper around the system default mutex +** implementation (sqlite3DefaultMutex()). +** +** Most calls are passed directly through to the underlying default +** mutex implementation. Except, if a mutex is configured by calling +** sqlite3MutexWarnOnContention() on it, then if contention is ever +** encountered within xMutexEnter() a warning is emitted via sqlite3_log(). +** +** This type of mutex is used as the database handle mutex when testing +** apps that usually use SQLITE_CONFIG_MULTITHREAD mode. +*/ + +/* +** Type for all mutexes used when SQLITE_ENABLE_MULTITHREADED_CHECKS +** is defined. Variable CheckMutex.mutex is a pointer to the real mutex +** allocated by the system mutex implementation. Variable iType is usually set +** to the type of mutex requested - SQLITE_MUTEX_RECURSIVE, SQLITE_MUTEX_FAST +** or one of the static mutex identifiers. Or, if this is a recursive mutex +** that has been configured using sqlite3MutexWarnOnContention(), it is +** set to SQLITE_MUTEX_WARNONCONTENTION. +*/ +typedef struct CheckMutex CheckMutex; +struct CheckMutex { + int iType; + sqlite3_mutex *mutex; +}; + +#define SQLITE_MUTEX_WARNONCONTENTION (-1) + +/* +** Pointer to real mutex methods object used by the CheckMutex +** implementation. Set by checkMutexInit(). +*/ +static SQLITE_WSD const sqlite3_mutex_methods *pGlobalMutexMethods; + +#ifdef SQLITE_DEBUG +static int checkMutexHeld(sqlite3_mutex *p){ + return pGlobalMutexMethods->xMutexHeld(((CheckMutex*)p)->mutex); +} +static int checkMutexNotheld(sqlite3_mutex *p){ + return pGlobalMutexMethods->xMutexNotheld(((CheckMutex*)p)->mutex); +} +#endif + +/* +** Initialize and deinitialize the mutex subsystem. +*/ +static int checkMutexInit(void){ + pGlobalMutexMethods = sqlite3DefaultMutex(); + return SQLITE_OK; +} +static int checkMutexEnd(void){ + pGlobalMutexMethods = 0; + return SQLITE_OK; +} + +/* +** Allocate a mutex. +*/ +static sqlite3_mutex *checkMutexAlloc(int iType){ + static CheckMutex staticMutexes[] = { + {2, 0}, {3, 0}, {4, 0}, {5, 0}, + {6, 0}, {7, 0}, {8, 0}, {9, 0}, + {10, 0}, {11, 0}, {12, 0}, {13, 0} + }; + CheckMutex *p = 0; + + assert( SQLITE_MUTEX_RECURSIVE==1 && SQLITE_MUTEX_FAST==0 ); + if( iType<2 ){ + p = sqlite3MallocZero(sizeof(CheckMutex)); + if( p==0 ) return 0; + p->iType = iType; + }else{ +#ifdef SQLITE_ENABLE_API_ARMOR + if( iType-2>=ArraySize(staticMutexes) ){ + (void)SQLITE_MISUSE_BKPT; + return 0; + } +#endif + p = &staticMutexes[iType-2]; + } + + if( p->mutex==0 ){ + p->mutex = pGlobalMutexMethods->xMutexAlloc(iType); + if( p->mutex==0 ){ + if( iType<2 ){ + sqlite3_free(p); + } + p = 0; + } + } + + return (sqlite3_mutex*)p; +} + +/* +** Free a mutex. +*/ +static void checkMutexFree(sqlite3_mutex *p){ + assert( SQLITE_MUTEX_RECURSIVE<2 ); + assert( SQLITE_MUTEX_FAST<2 ); + assert( SQLITE_MUTEX_WARNONCONTENTION<2 ); + +#if SQLITE_ENABLE_API_ARMOR + if( ((CheckMutex*)p)->iType<2 ) +#endif + { + CheckMutex *pCheck = (CheckMutex*)p; + pGlobalMutexMethods->xMutexFree(pCheck->mutex); + sqlite3_free(pCheck); + } +#ifdef SQLITE_ENABLE_API_ARMOR + else{ + (void)SQLITE_MISUSE_BKPT; + } +#endif +} + +/* +** Enter the mutex. +*/ +static void checkMutexEnter(sqlite3_mutex *p){ + CheckMutex *pCheck = (CheckMutex*)p; + if( pCheck->iType==SQLITE_MUTEX_WARNONCONTENTION ){ + if( SQLITE_OK==pGlobalMutexMethods->xMutexTry(pCheck->mutex) ){ + return; + } + sqlite3_log(SQLITE_MISUSE, + "illegal multi-threaded access to database connection" + ); + } + pGlobalMutexMethods->xMutexEnter(pCheck->mutex); +} + +/* +** Enter the mutex (do not block). +*/ +static int checkMutexTry(sqlite3_mutex *p){ + CheckMutex *pCheck = (CheckMutex*)p; + return pGlobalMutexMethods->xMutexTry(pCheck->mutex); +} + +/* +** Leave the mutex. +*/ +static void checkMutexLeave(sqlite3_mutex *p){ + CheckMutex *pCheck = (CheckMutex*)p; + pGlobalMutexMethods->xMutexLeave(pCheck->mutex); +} + +sqlite3_mutex_methods const *multiThreadedCheckMutex(void){ + static const sqlite3_mutex_methods sMutex = { + checkMutexInit, + checkMutexEnd, + checkMutexAlloc, + checkMutexFree, + checkMutexEnter, + checkMutexTry, + checkMutexLeave, +#ifdef SQLITE_DEBUG + checkMutexHeld, + checkMutexNotheld +#else + 0, + 0 +#endif + }; + return &sMutex; +} + +/* +** Mark the SQLITE_MUTEX_RECURSIVE mutex passed as the only argument as +** one on which there should be no contention. +*/ +void sqlite3MutexWarnOnContention(sqlite3_mutex *p){ + if( sqlite3GlobalConfig.mutex.xMutexAlloc==checkMutexAlloc ){ + CheckMutex *pCheck = (CheckMutex*)p; + assert( pCheck->iType==SQLITE_MUTEX_RECURSIVE ); + pCheck->iType = SQLITE_MUTEX_WARNONCONTENTION; + } +} +#endif /* ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS */ + +/* +** Initialize the mutex system. +*/ +int sqlite3MutexInit(void){ + int rc = SQLITE_OK; + if( !sqlite3GlobalConfig.mutex.xMutexAlloc ){ + /* If the xMutexAlloc method has not been set, then the user did not + ** install a mutex implementation via sqlite3_config() prior to + ** sqlite3_initialize() being called. This block copies pointers to + ** the default implementation into the sqlite3GlobalConfig structure. + */ + sqlite3_mutex_methods const *pFrom; + sqlite3_mutex_methods *pTo = &sqlite3GlobalConfig.mutex; + + if( sqlite3GlobalConfig.bCoreMutex ){ +#ifdef SQLITE_ENABLE_MULTITHREADED_CHECKS + pFrom = multiThreadedCheckMutex(); +#else + pFrom = sqlite3DefaultMutex(); +#endif + }else{ + pFrom = sqlite3NoopMutex(); + } + pTo->xMutexInit = pFrom->xMutexInit; + pTo->xMutexEnd = pFrom->xMutexEnd; + pTo->xMutexFree = pFrom->xMutexFree; + pTo->xMutexEnter = pFrom->xMutexEnter; + pTo->xMutexTry = pFrom->xMutexTry; + pTo->xMutexLeave = pFrom->xMutexLeave; + pTo->xMutexHeld = pFrom->xMutexHeld; + pTo->xMutexNotheld = pFrom->xMutexNotheld; + sqlite3MemoryBarrier(); + pTo->xMutexAlloc = pFrom->xMutexAlloc; + } + assert( sqlite3GlobalConfig.mutex.xMutexInit ); + rc = sqlite3GlobalConfig.mutex.xMutexInit(); + +#ifdef SQLITE_DEBUG + GLOBAL(int, mutexIsInit) = 1; +#endif + + sqlite3MemoryBarrier(); + return rc; +} + +/* +** Shutdown the mutex system. This call frees resources allocated by +** sqlite3MutexInit(). +*/ +int sqlite3MutexEnd(void){ + int rc = SQLITE_OK; + if( sqlite3GlobalConfig.mutex.xMutexEnd ){ + rc = sqlite3GlobalConfig.mutex.xMutexEnd(); + } + +#ifdef SQLITE_DEBUG + GLOBAL(int, mutexIsInit) = 0; +#endif + + return rc; +} + +/* +** Retrieve a pointer to a static mutex or allocate a new dynamic one. +*/ +sqlite3_mutex *sqlite3_mutex_alloc(int id){ +#ifndef SQLITE_OMIT_AUTOINIT + if( id<=SQLITE_MUTEX_RECURSIVE && sqlite3_initialize() ) return 0; + if( id>SQLITE_MUTEX_RECURSIVE && sqlite3MutexInit() ) return 0; +#endif + assert( sqlite3GlobalConfig.mutex.xMutexAlloc ); + return sqlite3GlobalConfig.mutex.xMutexAlloc(id); +} + +sqlite3_mutex *sqlite3MutexAlloc(int id){ + if( !sqlite3GlobalConfig.bCoreMutex ){ + return 0; + } + assert( GLOBAL(int, mutexIsInit) ); + assert( sqlite3GlobalConfig.mutex.xMutexAlloc ); + return sqlite3GlobalConfig.mutex.xMutexAlloc(id); +} + +/* +** Free a dynamic mutex. +*/ +void sqlite3_mutex_free(sqlite3_mutex *p){ + if( p ){ + assert( sqlite3GlobalConfig.mutex.xMutexFree ); + sqlite3GlobalConfig.mutex.xMutexFree(p); + } +} + +/* +** Obtain the mutex p. If some other thread already has the mutex, block +** until it can be obtained. +*/ +void sqlite3_mutex_enter(sqlite3_mutex *p){ + if( p ){ + assert( sqlite3GlobalConfig.mutex.xMutexEnter ); + sqlite3GlobalConfig.mutex.xMutexEnter(p); + } +} + +/* +** Obtain the mutex p. If successful, return SQLITE_OK. Otherwise, if another +** thread holds the mutex and it cannot be obtained, return SQLITE_BUSY. +*/ +int sqlite3_mutex_try(sqlite3_mutex *p){ + int rc = SQLITE_OK; + if( p ){ + assert( sqlite3GlobalConfig.mutex.xMutexTry ); + return sqlite3GlobalConfig.mutex.xMutexTry(p); + } + return rc; +} + +/* +** The sqlite3_mutex_leave() routine exits a mutex that was previously +** entered by the same thread. The behavior is undefined if the mutex +** is not currently entered. If a NULL pointer is passed as an argument +** this function is a no-op. +*/ +void sqlite3_mutex_leave(sqlite3_mutex *p){ + if( p ){ + assert( sqlite3GlobalConfig.mutex.xMutexLeave ); + sqlite3GlobalConfig.mutex.xMutexLeave(p); + } +} + +#ifndef NDEBUG +/* +** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are +** intended for use inside assert() statements. +*/ +int sqlite3_mutex_held(sqlite3_mutex *p){ + assert( p==0 || sqlite3GlobalConfig.mutex.xMutexHeld ); + return p==0 || sqlite3GlobalConfig.mutex.xMutexHeld(p); +} +int sqlite3_mutex_notheld(sqlite3_mutex *p){ + assert( p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld ); + return p==0 || sqlite3GlobalConfig.mutex.xMutexNotheld(p); +} +#endif + +#endif /* !defined(SQLITE_MUTEX_OMIT) */ |