diff options
Diffstat (limited to 'src/os_unix.c')
| -rw-r--r-- | src/os_unix.c | 128 |
1 files changed, 78 insertions, 50 deletions
diff --git a/src/os_unix.c b/src/os_unix.c index ca65836f4..48d2ff176 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 1.193 2008/07/10 00:32:42 drh Exp $ +** $Id: os_unix.c,v 1.194 2008/07/30 15:27:54 drh Exp $ */ #include "sqliteInt.h" #if SQLITE_OS_UNIX /* This file is used on unix only */ @@ -311,6 +311,7 @@ struct lockInfo { int cnt; /* Number of SHARED locks held */ int locktype; /* One of SHARED_LOCK, RESERVED_LOCK etc. */ int nRef; /* Number of pointers to this structure */ + struct lockInfo *pNext, *pPrev; /* List of all lockInfo objects */ }; /* @@ -336,15 +337,17 @@ struct openCnt { int nLock; /* Number of outstanding locks */ int nPending; /* Number of pending close() operations */ int *aPending; /* Malloced space holding fd's awaiting a close() */ + struct openCnt *pNext, *pPrev; /* List of all openCnt objects */ }; -/* -** These hash tables map inodes and file descriptors (really, lockKey and -** openKey structures) into lockInfo and openCnt structures. Access to -** these hash tables must be protected by a mutex. +/* +** List of all lockInfo and openCnt objects. This used to be a hash +** table. But the number of objects is rarely more than a dozen and +** never exceeds a few thousand. And lookup is not on a critical +** path oo a simple linked list will suffice. */ -static Hash lockHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0}; -static Hash openHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0}; +static struct lockInfo *lockList = 0; +static struct openCnt *openList = 0; /* ** The locking styles are associated with the different file locking @@ -362,9 +365,9 @@ static Hash openHash = {SQLITE_HASH_BINARY, 0, 0, 0, 0, 0}; ** file systems that are known to be unsupported */ #define LOCKING_STYLE_POSIX 1 -#define LOCKING_STYLE_FLOCK 2 +#define LOCKING_STYLE_NONE 2 #define LOCKING_STYLE_DOTFILE 3 -#define LOCKING_STYLE_NONE 4 +#define LOCKING_STYLE_FLOCK 4 #define LOCKING_STYLE_AFP 5 /* @@ -523,7 +526,17 @@ static void releaseLockInfo(struct lockInfo *pLock){ if( pLock ){ pLock->nRef--; if( pLock->nRef==0 ){ - sqlite3HashInsert(&lockHash, &pLock->key, sizeof(pLock->key), 0); + if( pLock->pPrev ){ + assert( pLock->pPrev->pNext==pLock ); + pLock->pPrev->pNext = pLock->pNext; + }else{ + assert( lockList==pLock ); + lockList = pLock->pNext; + } + if( pLock->pNext ){ + assert( pLock->pNext->pPrev==pLock ); + pLock->pNext->pPrev = pLock->pPrev; + } sqlite3_free(pLock); } } @@ -536,8 +549,18 @@ static void releaseOpenCnt(struct openCnt *pOpen){ if( pOpen ){ pOpen->nRef--; if( pOpen->nRef==0 ){ - sqlite3HashInsert(&openHash, &pOpen->key, sizeof(pOpen->key), 0); - free(pOpen->aPending); + if( pOpen->pPrev ){ + assert( pOpen->pPrev->pNext==pOpen ); + pOpen->pPrev->pNext = pOpen->pNext; + }else{ + assert( openList==pOpen ); + openList = pOpen->pNext; + } + if( pOpen->pNext ){ + assert( pOpen->pNext->pPrev==pOpen ); + pOpen->pNext->pPrev = pOpen->pPrev; + } + sqlite3_free(pOpen->aPending); sqlite3_free(pOpen); } } @@ -663,9 +686,11 @@ static int findLockInfo( memset(&key2, 0, sizeof(key2)); key2.dev = statbuf.st_dev; key2.ino = statbuf.st_ino; - pLock = (struct lockInfo*)sqlite3HashFind(&lockHash, &key1, sizeof(key1)); + pLock = lockList; + while( pLock && memcmp(&key1, &pLock->key, sizeof(key1)) ){ + pLock = pLock->pNext; + } if( pLock==0 ){ - struct lockInfo *pOld; pLock = sqlite3_malloc( sizeof(*pLock) ); if( pLock==0 ){ rc = SQLITE_NOMEM; @@ -675,21 +700,20 @@ static int findLockInfo( pLock->nRef = 1; pLock->cnt = 0; pLock->locktype = 0; - pOld = sqlite3HashInsert(&lockHash, &pLock->key, sizeof(key1), pLock); - if( pOld!=0 ){ - assert( pOld==pLock ); - sqlite3_free(pLock); - rc = SQLITE_NOMEM; - goto exit_findlockinfo; - } + pLock->pNext = lockList; + pLock->pPrev = 0; + if( lockList ) lockList->pPrev = pLock; + lockList = pLock; }else{ pLock->nRef++; } *ppLock = pLock; if( ppOpen!=0 ){ - pOpen = (struct openCnt*)sqlite3HashFind(&openHash, &key2, sizeof(key2)); + pOpen = openList; + while( pOpen && memcmp(&key2, &pOpen->key, sizeof(key2)) ){ + pOpen = pOpen->pNext; + } if( pOpen==0 ){ - struct openCnt *pOld; pOpen = sqlite3_malloc( sizeof(*pOpen) ); if( pOpen==0 ){ releaseLockInfo(pLock); @@ -701,14 +725,10 @@ static int findLockInfo( pOpen->nLock = 0; pOpen->nPending = 0; pOpen->aPending = 0; - pOld = sqlite3HashInsert(&openHash, &pOpen->key, sizeof(key2), pOpen); - if( pOld!=0 ){ - assert( pOld==pOpen ); - sqlite3_free(pOpen); - releaseLockInfo(pLock); - rc = SQLITE_NOMEM; - goto exit_findlockinfo; - } + pOpen->pNext = openList; + pOpen->pPrev = 0; + if( openList ) openList->pPrev = pOpen; + openList = pOpen; }else{ pOpen->nRef++; } @@ -1424,7 +1444,7 @@ static int unixUnlock(sqlite3_file *id, int locktype){ for(i=0; i<pOpen->nPending; i++){ close(pOpen->aPending[i]); } - free(pOpen->aPending); + sqlite3_free(pOpen->aPending); pOpen->nPending = 0; pOpen->aPending = 0; } @@ -1473,7 +1493,7 @@ static int unixClose(sqlite3_file *id){ */ int *aNew; struct openCnt *pOpen = pFile->pOpen; - aNew = realloc( pOpen->aPending, (pOpen->nPending+1)*sizeof(int) ); + aNew = sqlite3_realloc(pOpen->aPending, (pOpen->nPending+1)*sizeof(int) ); if( aNew==0 ){ /* If a malloc fails, just leak the file descriptor */ }else{ @@ -1970,7 +1990,7 @@ static int dotlockClose(sqlite3_file *id) { } -#pragma mark No locking +#endif /* SQLITE_ENABLE_LOCKING_STYLE */ /* ** The nolockLockingContext is void @@ -1997,8 +2017,6 @@ static int nolockClose(sqlite3_file *id) { return closeUnixFile(id); } -#endif /* SQLITE_ENABLE_LOCKING_STYLE */ - /* ** Information and control of an open file handle. @@ -2047,8 +2065,13 @@ static int fillInUnixFile( int h, /* Open file descriptor of file being opened */ int dirfd, /* Directory file descriptor */ sqlite3_file *pId, /* Write to the unixFile structure here */ - const char *zFilename /* Name of the file being opened */ + const char *zFilename, /* Name of the file being opened */ + int noLock /* Omit locking if true */ ){ + int eLockingStyle; + unixFile *pNew = (unixFile *)pId; + int rc = SQLITE_OK; + /* Macro to define the static contents of an sqlite3_io_methods ** structure for a unix backend file. Different locking methods ** require different functions for the xClose, xLock, xUnlock and @@ -2071,17 +2094,21 @@ static int fillInUnixFile( } static sqlite3_io_methods aIoMethod[] = { IOMETHODS(unixClose, unixLock, unixUnlock, unixCheckReservedLock) + ,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock) #ifdef SQLITE_ENABLE_LOCKING_STYLE - ,IOMETHODS(flockClose, flockLock, flockUnlock, flockCheckReservedLock) ,IOMETHODS(dotlockClose, dotlockLock, dotlockUnlock,dotlockCheckReservedLock) - ,IOMETHODS(nolockClose, nolockLock, nolockUnlock, nolockCheckReservedLock) + ,IOMETHODS(flockClose, flockLock, flockUnlock, flockCheckReservedLock) ,IOMETHODS(afpClose, afpLock, afpUnlock, afpCheckReservedLock) #endif }; - - int eLockingStyle; - unixFile *pNew = (unixFile *)pId; - int rc = SQLITE_OK; + /* The order of the IOMETHODS macros above is important. It must be the + ** same order as the LOCKING_STYLE numbers + */ + assert(LOCKING_STYLE_POSIX==1); + assert(LOCKING_STYLE_NONE==2); + assert(LOCKING_STYLE_DOTFILE==3); + assert(LOCKING_STYLE_FLOCK==4); + assert(LOCKING_STYLE_AFP==5); assert( pNew->pLock==NULL ); assert( pNew->pOpen==NULL ); @@ -2091,12 +2118,11 @@ static int fillInUnixFile( pNew->dirfd = dirfd; SET_THREADID(pNew); - assert(LOCKING_STYLE_POSIX==1); - assert(LOCKING_STYLE_FLOCK==2); - assert(LOCKING_STYLE_DOTFILE==3); - assert(LOCKING_STYLE_NONE==4); - assert(LOCKING_STYLE_AFP==5); - eLockingStyle = detectLockingStyle(pVfs, zFilename, h); + if( noLock ){ + eLockingStyle = LOCKING_STYLE_NONE; + }else{ + eLockingStyle = detectLockingStyle(pVfs, zFilename, h); + } switch( eLockingStyle ){ @@ -2280,6 +2306,7 @@ static int unixOpen( int dirfd = -1; /* Directory file descriptor */ int oflags = 0; /* Flags to pass to open() */ int eType = flags&0xFFFFFF00; /* Type of file to open */ + int noLock; /* True to omit locking primitives */ int isExclusive = (flags & SQLITE_OPEN_EXCLUSIVE); int isDelete = (flags & SQLITE_OPEN_DELETEONCLOSE); @@ -2375,7 +2402,8 @@ static int unixOpen( fcntl(fd, F_SETFD, fcntl(fd, F_GETFD, 0) | FD_CLOEXEC); #endif - return fillInUnixFile(pVfs, fd, dirfd, pFile, zPath); + noLock = eType!=SQLITE_OPEN_MAIN_DB; + return fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock); } /* |