diff options
Diffstat (limited to 'src/os_unix.c')
-rw-r--r-- | src/os_unix.c | 105 |
1 files changed, 53 insertions, 52 deletions
diff --git a/src/os_unix.c b/src/os_unix.c index 225a84d49..a22402bad 100644 --- a/src/os_unix.c +++ b/src/os_unix.c @@ -12,7 +12,7 @@ ** ** This file contains code that is specific to Unix systems. ** -** $Id: os_unix.c,v 1.220 2008/11/21 22:21:50 drh Exp $ +** $Id: os_unix.c,v 1.221 2008/11/25 12:07:41 danielk1977 Exp $ */ #include "sqliteInt.h" #if SQLITE_OS_UNIX /* This file is used on unix only */ @@ -513,57 +513,6 @@ static void testThreadLockingBehavior(int fd_orig){ #endif /* SQLITE_THERADSAFE && defined(__linux__) */ /* -** If we are currently in a different thread than the thread that the -** unixFile argument belongs to, then transfer ownership of the unixFile -** over to the current thread. -** -** A unixFile is only owned by a thread on systems where one thread is -** unable to override locks created by a different thread. RedHat9 is -** an example of such a system. -** -** Ownership transfer is only allowed if the unixFile is currently unlocked. -** If the unixFile is locked and an ownership is wrong, then return -** SQLITE_MISUSE. SQLITE_OK is returned if everything works. -*/ -#if SQLITE_THREADSAFE -static int transferOwnership(unixFile *pFile){ - int rc; - pthread_t hSelf; - if( threadsOverrideEachOthersLocks ){ - /* Ownership transfers not needed on this system */ - return SQLITE_OK; - } - hSelf = pthread_self(); - if( pthread_equal(pFile->tid, hSelf) ){ - /* We are still in the same thread */ - OSTRACE1("No-transfer, same thread\n"); - return SQLITE_OK; - } - if( pFile->locktype!=NO_LOCK ){ - /* We cannot change ownership while we are holding a lock! */ - return SQLITE_MISUSE; - } - OSTRACE4("Transfer ownership of %d from %d to %d\n", - pFile->h, pFile->tid, hSelf); - pFile->tid = hSelf; - if (pFile->pLock != NULL) { - releaseLockInfo(pFile->pLock); - rc = findLockInfo(pFile, &pFile->pLock, 0); - OSTRACE5("LOCK %d is now %s(%s,%d)\n", pFile->h, - locktypeName(pFile->locktype), - locktypeName(pFile->pLock->locktype), pFile->pLock->cnt); - return rc; - } else { - return SQLITE_OK; - } -} -#else /* if not SQLITE_THREADSAFE */ - /* On single-threaded builds, ownership transfer is a no-op */ -# define transferOwnership(X) SQLITE_OK -#endif /* SQLITE_THREADSAFE */ - - -/* ** Release a unixLockInfo structure previously allocated by findLockInfo(). */ static void releaseLockInfo(struct unixLockInfo *pLock){ @@ -586,6 +535,7 @@ static void releaseLockInfo(struct unixLockInfo *pLock){ } } + /* ** Release a unixOpenCnt structure previously allocated by findLockInfo(). */ @@ -1133,6 +1083,57 @@ static const char *locktypeName(int locktype){ #endif /* +** If we are currently in a different thread than the thread that the +** unixFile argument belongs to, then transfer ownership of the unixFile +** over to the current thread. +** +** A unixFile is only owned by a thread on systems where one thread is +** unable to override locks created by a different thread. RedHat9 is +** an example of such a system. +** +** Ownership transfer is only allowed if the unixFile is currently unlocked. +** If the unixFile is locked and an ownership is wrong, then return +** SQLITE_MISUSE. SQLITE_OK is returned if everything works. +*/ +#if SQLITE_THREADSAFE +static int transferOwnership(unixFile *pFile){ + int rc; + pthread_t hSelf; + if( threadsOverrideEachOthersLocks ){ + /* Ownership transfers not needed on this system */ + return SQLITE_OK; + } + hSelf = pthread_self(); + if( pthread_equal(pFile->tid, hSelf) ){ + /* We are still in the same thread */ + OSTRACE1("No-transfer, same thread\n"); + return SQLITE_OK; + } + if( pFile->locktype!=NO_LOCK ){ + /* We cannot change ownership while we are holding a lock! */ + return SQLITE_MISUSE; + } + OSTRACE4("Transfer ownership of %d from %d to %d\n", + pFile->h, pFile->tid, hSelf); + pFile->tid = hSelf; + if (pFile->pLock != NULL) { + releaseLockInfo(pFile->pLock); + rc = findLockInfo(pFile, &pFile->pLock, 0); + OSTRACE5("LOCK %d is now %s(%s,%d)\n", pFile->h, + locktypeName(pFile->locktype), + locktypeName(pFile->pLock->locktype), pFile->pLock->cnt); + return rc; + } else { + return SQLITE_OK; + } +} +#else /* if not SQLITE_THREADSAFE */ + /* On single-threaded builds, ownership transfer is a no-op */ +# define transferOwnership(X) SQLITE_OK +#endif /* SQLITE_THREADSAFE */ + + +/* ** Seek to the offset passed as the second argument, then read cnt ** bytes into pBuf. Return the number of bytes actually read. ** |