# endif
#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** Allowed values of unixFile.fsFlags
+*/
+#define SQLITE_FSFLAGS_IS_MSDOS 0x1
+
/*
** If we are to be thread-safe, include the pthreads header and define
** the SQLITE_UNIX_THREADS macro.
#if SQLITE_ENABLE_LOCKING_STYLE
int openFlags; /* The flags specified at open() */
#endif
+#if SQLITE_ENABLE_LOCKING_STYLE || defined(__APPLE__)
+ unsigned fsFlags; /* cached details from statfs() */
+#endif
#if SQLITE_THREADSAFE && defined(__linux__)
pthread_t tid; /* The thread that "owns" this unixFile */
#endif
int cnt; /* Number of SHARED locks held */
int locktype; /* One of SHARED_LOCK, RESERVED_LOCK etc. */
int nRef; /* Number of pointers to this structure */
+#if defined(SQLITE_ENABLE_LOCKING_STYLE)
+ unsigned long long sharedByte; /* for AFP simulated shared lock */
+#endif
struct unixLockInfo *pNext; /* List of all unixLockInfo objects */
struct unixLockInfo *pPrev; /* .... doubly linked */
};
** is a race condition such that another thread has already populated
** the first page of the database, no damage is done.
*/
- if( statbuf.st_size==0 ){
+ if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){
rc = write(fd, "S", 1);
if( rc!=1 ){
+ pFile->lastErrno = errno;
return SQLITE_IOERR;
}
rc = fstat(fd, &statbuf);
pLock->nRef = 1;
pLock->cnt = 0;
pLock->locktype = 0;
+#if defined(SQLITE_ENABLE_LOCKING_STYLE)
+ pLock->sharedByte = 0;
+#endif
pLock->pNext = lockList;
pLock->pPrev = 0;
if( lockList ) lockList->pPrev = pLock;
return rc;
}
-/*
-** Perform a file locking operation on a range of bytes in a file.
-** The "op" parameter should be one of F_RDLCK, F_WRLCK, or F_UNLCK.
-** Return 0 on success or -1 for failure. On failure, write the error
-** code into *pErrcode.
-**
-** If the SQLITE_WHOLE_FILE_LOCKING bit is clear, then only lock
-** the range of bytes on the locking page between SHARED_FIRST and
-** SHARED_SIZE. If SQLITE_WHOLE_FILE_LOCKING is set, then lock all
-** bytes from 0 up to but not including PENDING_BYTE, and all bytes
-** that follow SHARED_FIRST.
-**
-** In other words, of SQLITE_WHOLE_FILE_LOCKING if false (the historical
-** default case) then only lock a small range of bytes from SHARED_FIRST
-** through SHARED_FIRST+SHARED_SIZE-1. But if SQLITE_WHOLE_FILE_LOCKING is
-** true then lock every byte in the file except for PENDING_BYTE and
-** RESERVED_BYTE.
-**
-** SQLITE_WHOLE_FILE_LOCKING=true overlaps SQLITE_WHOLE_FILE_LOCKING=false
-** and so the locking schemes are compatible. One type of lock will
-** effectively exclude the other type. The reason for using the
-** SQLITE_WHOLE_FILE_LOCKING=true is that by indicating the full range
-** of bytes to be read or written, we give hints to NFS to help it
-** maintain cache coherency. On the other hand, whole file locking
-** is slower, so we don't want to use it except for NFS.
-*/
-static int rangeLock(unixFile *pFile, int op, int *pErrcode){
- struct flock lock;
- int rc;
- lock.l_type = op;
- lock.l_start = SHARED_FIRST;
- lock.l_whence = SEEK_SET;
- if( (pFile->fileFlags & SQLITE_WHOLE_FILE_LOCKING)==0 ){
- lock.l_len = SHARED_SIZE;
- rc = fcntl(pFile->h, F_SETLK, &lock);
- *pErrcode = errno;
- }else{
- lock.l_len = 0;
- rc = fcntl(pFile->h, F_SETLK, &lock);
- *pErrcode = errno;
- if( NEVER(op==F_UNLCK) || rc!=(-1) ){
- lock.l_start = 0;
- lock.l_len = PENDING_BYTE;
- rc = fcntl(pFile->h, F_SETLK, &lock);
- if( ALWAYS(op!=F_UNLCK) && rc==(-1) ){
- *pErrcode = errno;
- lock.l_type = F_UNLCK;
- lock.l_start = SHARED_FIRST;
- lock.l_len = 0;
- fcntl(pFile->h, F_SETLK, &lock);
- }
- }
- }
- return rc;
-}
-
/*
** Lock the file with the lock specified by parameter locktype - one
** of the following:
assert( pLock->locktype==0 );
/* Now get the read-lock */
- s = rangeLock(pFile, F_RDLCK, &tErrno);
-
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = SHARED_SIZE;
+ if( (s = fcntl(pFile->h, F_SETLK, &lock))==(-1) ){
+ tErrno = errno;
+ }
/* Drop the temporary PENDING lock */
lock.l_start = PENDING_BYTE;
lock.l_len = 1L;
switch( locktype ){
case RESERVED_LOCK:
lock.l_start = RESERVED_BYTE;
- s = fcntl(pFile->h, F_SETLK, &lock);
- tErrno = errno;
break;
case EXCLUSIVE_LOCK:
- s = rangeLock(pFile, F_WRLCK, &tErrno);
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = SHARED_SIZE;
break;
default:
assert(0);
}
+ s = fcntl(pFile->h, F_SETLK, &lock);
if( s==(-1) ){
+ tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
**
** If the locking level of the file descriptor is already at or below
** the requested locking level, this routine is a no-op.
+**
+** If handleNFSUnlock is true, then on downgrading an EXCLUSIVE_LOCK to SHARED
+** the byte range is divided into 2 parts and the first part is unlocked then
+** set to a read lock, then the other part is simply unlocked. This works
+** around a bug in BSD NFS lockd (also seen on MacOSX 10.3+) that fails to
+** remove the write lock on a region when a read lock is set.
*/
-static int unixUnlock(sqlite3_file *id, int locktype){
- unixFile *pFile = (unixFile*)id; /* The open file */
- struct unixLockInfo *pLock; /* Structure describing current lock state */
- struct flock lock; /* Information passed into fcntl() */
- int rc = SQLITE_OK; /* Return code from this interface */
- int h; /* The underlying file descriptor */
+static int _posixUnlock(sqlite3_file *id, int locktype, int handleNFSUnlock){
+ unixFile *pFile = (unixFile*)id;
+ struct unixLockInfo *pLock;
+ struct flock lock;
+ int rc = SQLITE_OK;
+ int h;
int tErrno; /* Error code from system call errors */
assert( pFile );
pFile->inNormalWrite = 0;
#endif
-
+ /* downgrading to a shared lock on NFS involves clearing the write lock
+ ** before establishing the readlock - to avoid a race condition we downgrade
+ ** the lock in 2 blocks, so that part of the range will be covered by a
+ ** write lock until the rest is covered by a read lock:
+ ** 1: [WWWWW]
+ ** 2: [....W]
+ ** 3: [RRRRW]
+ ** 4: [RRRR.]
+ */
if( locktype==SHARED_LOCK ){
- if( rangeLock(pFile, F_RDLCK, &tErrno)==(-1) ){
- rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
- if( IS_LOCK_ERROR(rc) ){
- pFile->lastErrno = tErrno;
+ if( handleNFSUnlock ){
+ off_t divSize = SHARED_SIZE - 1;
+
+ lock.l_type = F_UNLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = divSize;
+ if( fcntl(h, F_SETLK, &lock)==(-1) ){
+ int tErrno = errno;
+ rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
+ if( IS_LOCK_ERROR(rc) ){
+ pFile->lastErrno = tErrno;
+ }
+ goto end_unlock;
+ }
+ lock.l_type = F_RDLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = divSize;
+ if( fcntl(h, F_SETLK, &lock)==(-1) ){
+ int tErrno = errno;
+ rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
+ if( IS_LOCK_ERROR(rc) ){
+ pFile->lastErrno = tErrno;
+ }
+ goto end_unlock;
+ }
+ lock.l_type = F_UNLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = SHARED_FIRST+divSize;
+ lock.l_len = SHARED_SIZE-divSize;
+ if( fcntl(h, F_SETLK, &lock)==(-1) ){
+ int tErrno = errno;
+ rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
+ if( IS_LOCK_ERROR(rc) ){
+ pFile->lastErrno = tErrno;
+ }
+ goto end_unlock;
+ }
+ }else{
+ lock.l_type = F_RDLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = SHARED_SIZE;
+ if( fcntl(h, F_SETLK, &lock)==(-1) ){
+ int tErrno = errno;
+ rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
+ if( IS_LOCK_ERROR(rc) ){
+ pFile->lastErrno = tErrno;
+ }
+ goto end_unlock;
}
- goto end_unlock;
}
}
lock.l_type = F_UNLCK;
return rc;
}
+/*
+** Lower the locking level on file descriptor pFile to locktype. locktype
+** must be either NO_LOCK or SHARED_LOCK.
+**
+** If the locking level of the file descriptor is already at or below
+** the requested locking level, this routine is a no-op.
+*/
+static int unixUnlock(sqlite3_file *id, int locktype){
+ return _posixUnlock(id, locktype, 0);
+}
+
/*
** This function performs the parts of the "close file" operation
** common to all locking schemes. It closes the directory and file
*/
typedef struct afpLockingContext afpLockingContext;
struct afpLockingContext {
- unsigned long long sharedByte;
+ int reserved;
const char *dbPath; /* Name of the open file */
};
assert( pFile );
afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+ if( context->reserved ){
+ *pResOut = 1;
+ return SQLITE_OK;
+ }
+ unixEnterMutex(); /* Because pFile->pLock is shared across threads */
/* Check if a thread in this process holds such a lock */
- if( pFile->locktype>SHARED_LOCK ){
+ if( pFile->pLock->locktype>SHARED_LOCK ){
reserved = 1;
}
}
}
+ unixLeaveMutex();
OSTRACE4("TEST WR-LOCK %d %d %d (afp)\n", pFile->h, rc, reserved);
*pResOut = reserved;
static int afpLock(sqlite3_file *id, int locktype){
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
+ struct unixLockInfo *pLock = pFile->pLock;
afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
assert( pFile );
- OSTRACE5("LOCK %d %s was %s pid=%d (afp)\n", pFile->h,
- locktypeName(locktype), locktypeName(pFile->locktype), getpid());
+ OSTRACE7("LOCK %d %s was %s(%s,%d) pid=%d (afp)\n", pFile->h,
+ locktypeName(locktype), locktypeName(pFile->locktype),
+ locktypeName(pLock->locktype), pLock->cnt , getpid());
/* If there is already a lock of this type or more restrictive on the
** unixFile, do nothing. Don't use the afp_end_lock: exit path, as
}
/* Make sure the locking sequence is correct
+ ** (1) We never move from unlocked to anything higher than shared lock.
+ ** (2) SQLite never explicitly requests a pendig lock.
+ ** (3) A shared lock is always held when a reserve lock is requested.
*/
assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
assert( locktype!=PENDING_LOCK );
unixLeaveMutex();
return rc;
}
+ pLock = pFile->pLock;
+
+ /* If some thread using this PID has a lock via a different unixFile*
+ ** handle that precludes the requested lock, return BUSY.
+ */
+ if( (pFile->locktype!=pLock->locktype &&
+ (pLock->locktype>=PENDING_LOCK || locktype>SHARED_LOCK))
+ ){
+ rc = SQLITE_BUSY;
+ goto afp_end_lock;
+ }
+
+ /* If a SHARED lock is requested, and some thread using this PID already
+ ** has a SHARED or RESERVED lock, then increment reference counts and
+ ** return SQLITE_OK.
+ */
+ if( locktype==SHARED_LOCK &&
+ (pLock->locktype==SHARED_LOCK || pLock->locktype==RESERVED_LOCK) ){
+ assert( locktype==SHARED_LOCK );
+ assert( pFile->locktype==0 );
+ assert( pLock->cnt>0 );
+ pFile->locktype = SHARED_LOCK;
+ pLock->cnt++;
+ pFile->pOpen->nLock++;
+ goto afp_end_lock;
+ }
/* A PENDING lock is needed before acquiring a SHARED lock and before
** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will
** operating system calls for the specified lock.
*/
if( locktype==SHARED_LOCK ){
- int lk, lrc1, lrc2;
- int lrc1Errno = 0;
+ int lrc1, lrc2, lrc1Errno;
+ long lk, mask;
+ assert( pLock->cnt==0 );
+ assert( pLock->locktype==0 );
+
+ mask = (sizeof(long)==8) ? LARGEST_INT64 : 0x7fffffff;
/* Now get the read-lock SHARED_LOCK */
/* note that the quality of the randomness doesn't matter that much */
lk = random();
- context->sharedByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
+ pLock->sharedByte = (lk & mask)%(SHARED_SIZE - 1);
lrc1 = afpSetLock(context->dbPath, pFile,
- SHARED_FIRST+context->sharedByte, 1, 1);
+ SHARED_FIRST+pLock->sharedByte, 1, 1);
if( IS_LOCK_ERROR(lrc1) ){
lrc1Errno = pFile->lastErrno;
}
} else {
pFile->locktype = SHARED_LOCK;
pFile->pOpen->nLock++;
+ pLock->cnt = 1;
}
+ }else if( locktype==EXCLUSIVE_LOCK && pLock->cnt>1 ){
+ /* We are trying for an exclusive lock but another thread in this
+ ** same process is still holding a shared lock. */
+ rc = SQLITE_BUSY;
}else{
/* The request was for a RESERVED or EXCLUSIVE lock. It is
** assumed that there is a SHARED or greater lock on the file
if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
/* Acquire a RESERVED lock */
failed = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1,1);
+ if( !failed ){
+ context->reserved = 1;
+ }
}
if (!failed && locktype == EXCLUSIVE_LOCK) {
/* Acquire an EXCLUSIVE lock */
** reestablish the shared lock if we can't get the afpUnlock
*/
if( !(failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST +
- context->sharedByte, 1, 0)) ){
+ pLock->sharedByte, 1, 0)) ){
int failed2 = SQLITE_OK;
/* now attemmpt to get the exclusive lock range */
failed = afpSetLock(context->dbPath, pFile, SHARED_FIRST,
SHARED_SIZE, 1);
if( failed && (failed2 = afpSetLock(context->dbPath, pFile,
- SHARED_FIRST + context->sharedByte, 1, 1)) ){
+ SHARED_FIRST + pLock->sharedByte, 1, 1)) ){
/* Can't reestablish the shared lock. Sqlite can't deal, this is
** a critical I/O error
*/
if( rc==SQLITE_OK ){
pFile->locktype = locktype;
+ pLock->locktype = locktype;
}else if( locktype==EXCLUSIVE_LOCK ){
pFile->locktype = PENDING_LOCK;
+ pLock->locktype = PENDING_LOCK;
}
afp_end_lock:
static int afpUnlock(sqlite3_file *id, int locktype) {
int rc = SQLITE_OK;
unixFile *pFile = (unixFile*)id;
- afpLockingContext *pCtx = (afpLockingContext *) pFile->lockingContext;
+ struct unixLockInfo *pLock;
+ afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+ int skipShared = 0;
+#ifdef SQLITE_TEST
+ int h = pFile->h;
+#endif
assert( pFile );
- OSTRACE5("UNLOCK %d %d was %d pid=%d (afp)\n", pFile->h, locktype,
- pFile->locktype, getpid());
+ OSTRACE7("UNLOCK %d %d was %d(%d,%d) pid=%d (afp)\n", pFile->h, locktype,
+ pFile->locktype, pFile->pLock->locktype, pFile->pLock->cnt, getpid());
assert( locktype<=SHARED_LOCK );
if( pFile->locktype<=locktype ){
return SQLITE_MISUSE;
}
unixEnterMutex();
+ pLock = pFile->pLock;
+ assert( pLock->cnt!=0 );
if( pFile->locktype>SHARED_LOCK ){
+ assert( pLock->locktype==pFile->locktype );
+ SimulateIOErrorBenign(1);
+ SimulateIOError( h=(-1) )
+ SimulateIOErrorBenign(0);
+
+#ifndef NDEBUG
+ /* When reducing a lock such that other processes can start
+ ** reading the database file again, make sure that the
+ ** transaction counter was updated if any part of the database
+ ** file changed. If the transaction counter is not updated,
+ ** other connections to the same file might not realize that
+ ** the file has changed and hence might not know to flush their
+ ** cache. The use of a stale cache can lead to database corruption.
+ */
+ assert( pFile->inNormalWrite==0
+ || pFile->dbUpdate==0
+ || pFile->transCntrChng==1 );
+ pFile->inNormalWrite = 0;
+#endif
if( pFile->locktype==EXCLUSIVE_LOCK ){
- rc = afpSetLock(pCtx->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
- if( rc==SQLITE_OK && locktype==SHARED_LOCK ){
+ rc = afpSetLock(context->dbPath, pFile, SHARED_FIRST, SHARED_SIZE, 0);
+ if( rc==SQLITE_OK && (locktype==SHARED_LOCK || pLock->cnt>1) ){
/* only re-establish the shared lock if necessary */
- int sharedLockByte = SHARED_FIRST+pCtx->sharedByte;
- rc = afpSetLock(pCtx->dbPath, pFile, sharedLockByte, 1, 1);
+ int sharedLockByte = SHARED_FIRST+pLock->sharedByte;
+ rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 1);
+ } else {
+ skipShared = 1;
}
}
if( rc==SQLITE_OK && pFile->locktype>=PENDING_LOCK ){
- rc = afpSetLock(pCtx->dbPath, pFile, PENDING_BYTE, 1, 0);
+ rc = afpSetLock(context->dbPath, pFile, PENDING_BYTE, 1, 0);
}
- if( rc==SQLITE_OK && pFile->locktype>=RESERVED_LOCK ){
- rc = afpSetLock(pCtx->dbPath, pFile, RESERVED_BYTE, 1, 0);
+ if( rc==SQLITE_OK && pFile->locktype>=RESERVED_LOCK && context->reserved ){
+ rc = afpSetLock(context->dbPath, pFile, RESERVED_BYTE, 1, 0);
+ if( !rc ){
+ context->reserved = 0;
+ }
+ }
+ if( rc==SQLITE_OK && (locktype==SHARED_LOCK || pLock->cnt>1)){
+ pLock->locktype = SHARED_LOCK;
}
- }else if( locktype==NO_LOCK ){
- /* clear the shared lock */
- int sharedLockByte = SHARED_FIRST+pCtx->sharedByte;
- rc = afpSetLock(pCtx->dbPath, pFile, sharedLockByte, 1, 0);
}
+ if( rc==SQLITE_OK && locktype==NO_LOCK ){
- if( rc==SQLITE_OK ){
- if( locktype==NO_LOCK ){
+ /* Decrement the shared lock counter. Release the lock using an
+ ** OS call only when all threads in this same process have released
+ ** the lock.
+ */
+ unsigned long long sharedLockByte = SHARED_FIRST+pLock->sharedByte;
+ pLock->cnt--;
+ if( pLock->cnt==0 ){
+ SimulateIOErrorBenign(1);
+ SimulateIOError( h=(-1) )
+ SimulateIOErrorBenign(0);
+ if( !skipShared ){
+ rc = afpSetLock(context->dbPath, pFile, sharedLockByte, 1, 0);
+ }
+ if( !rc ){
+ pLock->locktype = NO_LOCK;
+ pFile->locktype = NO_LOCK;
+ }
+ }
+ if( rc==SQLITE_OK ){
struct unixOpenCnt *pOpen = pFile->pOpen;
+
pOpen->nLock--;
assert( pOpen->nLock>=0 );
if( pOpen->nLock==0 ){
}
}
}
+
unixLeaveMutex();
- if( rc==SQLITE_OK ){
- pFile->locktype = locktype;
- }
+ if( rc==SQLITE_OK ) pFile->locktype = locktype;
return rc;
}
** Close a file & cleanup AFP specific locking context
*/
static int afpClose(sqlite3_file *id) {
+ int rc = SQLITE_OK;
if( id ){
unixFile *pFile = (unixFile*)id;
afpUnlock(id, NO_LOCK);
*/
setPendingFd(pFile);
}
+ releaseLockInfo(pFile->pLock);
releaseOpenCnt(pFile->pOpen);
sqlite3_free(pFile->lockingContext);
- closeUnixFile(id);
+ rc = closeUnixFile(id);
unixLeaveMutex();
}
- return SQLITE_OK;
+ return rc;
}
#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
********************* End of the AFP lock implementation **********************
******************************************************************************/
+/******************************************************************************
+*************************** Begin NFS Locking ********************************/
+
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+/*
+ ** Lower the locking level on file descriptor pFile to locktype. locktype
+ ** must be either NO_LOCK or SHARED_LOCK.
+ **
+ ** If the locking level of the file descriptor is already at or below
+ ** the requested locking level, this routine is a no-op.
+ */
+static int nfsUnlock(sqlite3_file *id, int locktype){
+ return _posixUnlock(id, locktype, 1);
+}
+
+#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
+/*
+** The code above is the NFS lock implementation. The code is specific
+** to MacOSX and does not work on other unix platforms. No alternative
+** is available.
+**
+********************* End of the NFS lock implementation **********************
+******************************************************************************/
/******************************************************************************
**************** Non-locking sqlite3_file methods *****************************
*/
static int seekAndRead(unixFile *id, sqlite3_int64 offset, void *pBuf, int cnt){
int got;
+#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
i64 newOffset;
+#endif
TIMER_START;
#if defined(USE_PREAD)
got = pread(id->h, pBuf, cnt, offset);
*/
static int seekAndWrite(unixFile *id, i64 offset, const void *pBuf, int cnt){
int got;
+#if (!defined(USE_PREAD) && !defined(USE_PREAD64))
i64 newOffset;
+#endif
TIMER_START;
#if defined(USE_PREAD)
got = pwrite(id->h, pBuf, cnt, offset);
*/
if( rc ) rc = fsync(fd);
+#elif defined(__APPLE__)
+ /* fdatasync() on HFS+ doesn't yet flush the file size if it changed correctly
+ ** so currently we default to the macro that redefines fdatasync to fsync
+ */
+ rc = fsync(fd);
#else
rc = fdatasync(fd);
#if OS_VXWORKS
)
#endif
-/*
-** The "Whole File Locking" finder returns the same set of methods as
-** the posix locking finder. But it also sets the SQLITE_WHOLE_FILE_LOCKING
-** flag to force the posix advisory locks to cover the whole file instead
-** of just a small span of bytes near the 1GiB boundary. Whole File Locking
-** is useful on NFS-mounted files since it helps NFS to maintain cache
-** coherency. But it is a detriment to other filesystems since it runs
-** slower.
-*/
-static const sqlite3_io_methods *posixWflIoFinderImpl(const char*z, unixFile*p){
- UNUSED_PARAMETER(z);
- p->fileFlags = SQLITE_WHOLE_FILE_LOCKING;
- return &posixIoMethods;
-}
-static const sqlite3_io_methods
- *(*const posixWflIoFinder)(const char*,unixFile *p) = posixWflIoFinderImpl;
-
/*
** The proxy locking method is a "super-method" in the sense that it
** opens secondary file descriptors for the conch and lock files and
)
#endif
+/* nfs lockd on OSX 10.3+ doesn't clear write locks when a read lock is set */
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+IOMETHODS(
+ nfsIoFinder, /* Finder function name */
+ nfsIoMethods, /* sqlite3_io_methods object name */
+ unixClose, /* xClose method */
+ unixLock, /* xLock method */
+ nfsUnlock, /* xUnlock method */
+ unixCheckReservedLock /* xCheckReservedLock method */
+)
+#endif
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
/*
{ "hfs", &posixIoMethods },
{ "ufs", &posixIoMethods },
{ "afpfs", &afpIoMethods },
-#ifdef SQLITE_ENABLE_AFP_LOCKING_SMB
{ "smbfs", &afpIoMethods },
-#else
- { "smbfs", &flockIoMethods },
-#endif
{ "webdav", &nolockIoMethods },
{ 0, 0 }
};
lockInfo.l_whence = SEEK_SET;
lockInfo.l_type = F_RDLCK;
if( fcntl(pNew->h, F_GETLK, &lockInfo)!=-1 ) {
- pNew->fileFlags = SQLITE_WHOLE_FILE_LOCKING;
- return &posixIoMethods;
+ if( strcmp(fsInfo.f_fstypename, "nfs")==0 ){
+ return &nfsIoMethods;
+ } else {
+ return &posixIoMethods;
+ }
}else{
return &dotlockIoMethods;
}
#endif
}
- if( pLockingStyle == &posixIoMethods ){
+ if( pLockingStyle == &posixIoMethods
+#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
+ || pLockingStyle == &nfsIoMethods
+#endif
+ ){
unixEnterMutex();
rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
if( rc!=SQLITE_OK ){
** according to requirement F11141. So we do not need to make a
** copy of the filename. */
pCtx->dbPath = zFilename;
+ pCtx->reserved = 0;
srandomdev();
unixEnterMutex();
- rc = findLockInfo(pNew, NULL, &pNew->pOpen);
+ rc = findLockInfo(pNew, &pNew->pLock, &pNew->pOpen);
+ if( rc!=SQLITE_OK ){
+ sqlite3_free(pNew->lockingContext);
+ close(h);
+ h = -1;
+ }
unixLeaveMutex();
}
}
int isCreate = (flags & SQLITE_OPEN_CREATE);
int isReadonly = (flags & SQLITE_OPEN_READONLY);
int isReadWrite = (flags & SQLITE_OPEN_READWRITE);
+#if SQLITE_ENABLE_LOCKING_STYLE
+ int isAutoProxy = (flags & SQLITE_OPEN_AUTOPROXY);
+#endif
/* If creating a master or main-file journal, this function will open
** a file-descriptor on the directory too. The first time unixSync()
noLock = eType!=SQLITE_OPEN_MAIN_DB;
+
+#if defined(__APPLE__) || SQLITE_ENABLE_LOCKING_STYLE
+ struct statfs fsInfo;
+ if( fstatfs(fd, &fsInfo) == -1 ){
+ ((unixFile*)pFile)->lastErrno = errno;
+ if( dirfd>=0 ) close(dirfd); /* silently leak if fail, in error */
+ close(fd); /* silently leak if fail, in error */
+ return SQLITE_IOERR_ACCESS;
+ }
+ if (0 == strncmp("msdos", fsInfo.f_fstypename, 5)) {
+ ((unixFile*)pFile)->fsFlags |= SQLITE_FSFLAGS_IS_MSDOS;
+ }
+#endif
+
+#if SQLITE_ENABLE_LOCKING_STYLE
#if SQLITE_PREFER_PROXY_LOCKING
- if( zPath!=NULL && !noLock && pVfs->xOpen ){
+ isAutoProxy = 1;
+#endif
+ if( isAutoProxy && (zPath!=NULL) && (!noLock) && pVfs->xOpen ){
char *envforce = getenv("SQLITE_FORCE_PROXY_LOCKING");
int useProxy = 0;
rc = fillInUnixFile(pVfs, fd, dirfd, pFile, zPath, noLock, isDelete);
if( rc==SQLITE_OK ){
rc = proxyTransformUnixFile((unixFile*)pFile, ":auto:");
+ if( rc!=SQLITE_OK ){
+ /* Use unixClose to clean up the resources added in fillInUnixFile
+ ** and clear all the structure's references. Specifically,
+ ** pFile->pMethods will be NULL so sqlite3OsClose will be a no-op
+ */
+ unixClose(pFile);
+ return rc;
+ }
}
goto open_finished;
}
** of the database file for multiple readers and writers on the same
** host (the conch ensures that they all use the same local lock file).
**
-** There is a third file - the host ID file - used as a persistent record
-** of a unique identifier for the host, a 128-byte unique host id file
-** in the path defined by the HOSTIDPATH macro (default value is
-** /Library/Caches/.com.apple.sqliteConchHostId).
-**
** Requesting the lock proxy does not immediately take the conch, it is
** only taken when the first request to lock database file is made.
** This matches the semantics of the traditional locking behavior, where
** Enables the logging of error messages during host id file
** retrieval and creation
**
-** HOSTIDPATH
-**
-** Overrides the default host ID file path location
-**
** LOCKPROXYDIR
**
** Overrides the default directory used for lock proxy files that
*/
#if defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE
-#ifdef SQLITE_TEST
-/* simulate multiple hosts by creating unique hostid file paths */
-int sqlite3_hostid_num = 0;
-#endif
-
/*
** The proxyLockingContext has the path and file structures for the remote
** and local proxy files in it
unixFile *lockProxy; /* Open proxy lock file */
char *lockProxyPath; /* Name of the proxy lock file */
char *dbPath; /* Name of the open file */
- int conchHeld; /* True if the conch is currently held */
+ int conchHeld; /* 1 if the conch is held, -1 if lockless */
void *oldLockingContext; /* Original lockingcontext to restore on close */
sqlite3_io_methods const *pOldMethod; /* Original I/O methods for close */
};
-/* HOSTIDLEN and CONCHLEN both include space for the string
-** terminating nul
-*/
-#define HOSTIDLEN 128
-#define CONCHLEN (MAXPATHLEN+HOSTIDLEN+1)
-#ifndef HOSTIDPATH
-# define HOSTIDPATH "/Library/Caches/.com.apple.sqliteConchHostId"
-#endif
-
-/* basically a copy of unixRandomness with different
-** test behavior built in */
-static int proxyGenerateHostID(char *pHostID){
- int pid, fd, len;
- unsigned char *key = (unsigned char *)pHostID;
-
- memset(key, 0, HOSTIDLEN);
- len = 0;
- fd = open("/dev/urandom", O_RDONLY);
- if( fd>=0 ){
- len = read(fd, key, HOSTIDLEN);
- close(fd); /* silently leak the fd if it fails */
- }
- if( len < HOSTIDLEN ){
- time_t t;
- time(&t);
- memcpy(key, &t, sizeof(t));
- pid = getpid();
- memcpy(&key[sizeof(t)], &pid, sizeof(pid));
- }
-
-#ifdef MAKE_PRETTY_HOSTID
- {
- int i;
- /* filter the bytes into printable ascii characters and NUL terminate */
- key[(HOSTIDLEN-1)] = 0x00;
- for( i=0; i<(HOSTIDLEN-1); i++ ){
- unsigned char pa = key[i]&0x7F;
- if( pa<0x20 ){
- key[i] = (key[i]&0x80 == 0x80) ? pa+0x40 : pa+0x20;
- }else if( pa==0x7F ){
- key[i] = (key[i]&0x80 == 0x80) ? pa=0x20 : pa+0x7E;
- }
- }
- }
-#endif
- return SQLITE_OK;
-}
-
-/* writes the host id path to path, path should be an pre-allocated buffer
-** with enough space for a path
-*/
-static void proxyGetHostIDPath(char *path, size_t len){
- strlcpy(path, HOSTIDPATH, len);
-#ifdef SQLITE_TEST
- if( sqlite3_hostid_num>0 ){
- char suffix[2] = "1";
- suffix[0] = suffix[0] + sqlite3_hostid_num;
- strlcat(path, suffix, len);
- }
-#endif
- OSTRACE3("GETHOSTIDPATH %s pid=%d\n", path, getpid());
-}
-
-/* get the host ID from a sqlite hostid file stored in the
-** user-specific tmp directory, create the ID if it's not there already
+/*
+** The proxy lock file path for the database at dbPath is written into lPath,
+** which must point to valid, writable memory large enough for a maxLen length
+** file path.
*/
-static int proxyGetHostID(char *pHostID, int *pError){
- int fd;
- char path[MAXPATHLEN];
- size_t len;
- int rc=SQLITE_OK;
-
- proxyGetHostIDPath(path, MAXPATHLEN);
- /* try to create the host ID file, if it already exists read the contents */
- fd = open(path, O_CREAT|O_WRONLY|O_EXCL, 0644);
- if( fd<0 ){
- int err=errno;
-
- if( err!=EEXIST ){
-#ifdef SQLITE_PROXY_DEBUG /* set the sqlite error message instead */
- fprintf(stderr, "sqlite error creating host ID file %s: %s\n",
- path, strerror(err));
-#endif
- return SQLITE_PERM;
- }
- /* couldn't create the file, read it instead */
- fd = open(path, O_RDONLY|O_EXCL);
- if( fd<0 ){
-#ifdef SQLITE_PROXY_DEBUG /* set the sqlite error message instead */
- int err = errno;
- fprintf(stderr, "sqlite error opening host ID file %s: %s\n",
- path, strerror(err));
-#endif
- return SQLITE_PERM;
- }
- len = pread(fd, pHostID, HOSTIDLEN, 0);
- if( len<0 ){
- *pError = errno;
- rc = SQLITE_IOERR_READ;
- }else if( len<HOSTIDLEN ){
- *pError = 0;
- rc = SQLITE_IOERR_SHORT_READ;
- }
- close(fd); /* silently leak the fd if it fails */
- OSTRACE3("GETHOSTID read %s pid=%d\n", pHostID, getpid());
- return rc;
- }else{
- /* we're creating the host ID file (use a random string of bytes) */
- proxyGenerateHostID(pHostID);
- len = pwrite(fd, pHostID, HOSTIDLEN, 0);
- if( len<0 ){
- *pError = errno;
- rc = SQLITE_IOERR_WRITE;
- }else if( len<HOSTIDLEN ){
- *pError = 0;
- rc = SQLITE_IOERR_WRITE;
- }
- close(fd); /* silently leak the fd if it fails */
- OSTRACE3("GETHOSTID wrote %s pid=%d\n", pHostID, getpid());
- return rc;
- }
-}
-
static int proxyGetLockPath(const char *dbPath, char *lPath, size_t maxLen){
int len;
int dbLen;
#else
# ifdef _CS_DARWIN_USER_TEMP_DIR
{
- confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen);
- len = strlcat(lPath, "sqliteplocks", maxLen);
- if( mkdir(lPath, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
- /* if mkdir fails, handle as lock file creation failure */
-# ifdef SQLITE_DEBUG
- int err = errno;
- if( err!=EEXIST ){
- fprintf(stderr, "proxyGetLockPath: mkdir(%s,0%o) error %d %s\n", lPath,
- SQLITE_DEFAULT_PROXYDIR_PERMISSIONS, err, strerror(err));
- }
-# endif
- }else{
- OSTRACE3("GETLOCKPATH mkdir %s pid=%d\n", lPath, getpid());
+ if( !confstr(_CS_DARWIN_USER_TEMP_DIR, lPath, maxLen) ){
+ OSTRACE4("GETLOCKPATH failed %s errno=%d pid=%d\n",
+ lPath, errno, getpid());
+ return SQLITE_IOERR_LOCK;
}
-
+ len = strlcat(lPath, "sqliteplocks", maxLen);
}
# else
len = strlcpy(lPath, "/tmp/", maxLen);
}
lPath[i+len]='\0';
strlcat(lPath, ":auto:", maxLen);
+ OSTRACE3("GETLOCKPATH proxy lock path=%s pid=%d\n", lPath, getpid());
return SQLITE_OK;
}
+/*
+ ** Creates the lock file and any missing directories in lockPath
+ */
+static int proxyCreateLockPath(const char *lockPath){
+ int i, len;
+ char buf[MAXPATHLEN];
+ int start = 0;
+
+ assert(lockPath!=NULL);
+ /* try to create all the intermediate directories */
+ len = (int)strlen(lockPath);
+ buf[0] = lockPath[0];
+ for( i=1; i<len; i++ ){
+ if( lockPath[i] == '/' && (i - start > 0) ){
+ /* only mkdir if leaf dir != "." or "/" or ".." */
+ if( i-start>2 || (i-start==1 && buf[start] != '.' && buf[start] != '/')
+ || (i-start==2 && buf[start] != '.' && buf[start+1] != '.') ){
+ buf[i]='\0';
+ if( mkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
+ int err=errno;
+ if( err!=EEXIST ) {
+ OSTRACE5("CREATELOCKPATH FAILED creating %s, "
+ "'%s' proxy lock path=%s pid=%d\n",
+ buf, strerror(err), lockPath, getpid());
+ return err;
+ }
+ }
+ }
+ start=i+1;
+ }
+ buf[i] = lockPath[i];
+ }
+ OSTRACE3("CREATELOCKPATH proxy lock path=%s pid=%d\n", lockPath, getpid());
+ return 0;
+}
+
/*
** Create a new VFS file descriptor (stored in memory obtained from
** sqlite3_malloc) and open the file named "path" in the file descriptor.
** The caller is responsible not only for closing the file descriptor
** but also for freeing the memory associated with the file descriptor.
*/
-static int proxyCreateUnixFile(const char *path, unixFile **ppFile) {
+static int proxyCreateUnixFile(
+ const char *path, /* path for the new unixFile */
+ unixFile **ppFile, /* unixFile created and returned by ref */
+ int islockfile /* if non zero missing dirs will be created */
+) {
+ int fd = -1;
+ int dirfd = -1;
unixFile *pNew;
- int flags = SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE;
int rc = SQLITE_OK;
+ int openFlags = O_RDWR | O_CREAT;
sqlite3_vfs dummyVfs;
-
- pNew = (unixFile *)sqlite3_malloc(sizeof(unixFile));
- if( !pNew ){
- return SQLITE_NOMEM;
+ int terrno = 0;
+ UnixUnusedFd *pUnused = NULL;
+
+ /* 1. first try to open/create the file
+ ** 2. if that fails, and this is a lock file (not-conch), try creating
+ ** the parent directories and then try again.
+ ** 3. if that fails, try to open the file read-only
+ ** otherwise return BUSY (if lock file) or CANTOPEN for the conch file
+ */
+ pUnused = findReusableFd(path, openFlags);
+ if( pUnused ){
+ fd = pUnused->fd;
+ }else{
+ pUnused = sqlite3_malloc(sizeof(*pUnused));
+ if( !pUnused ){
+ return SQLITE_NOMEM;
+ }
+ }
+ if( fd<0 ){
+ fd = open(path, openFlags, SQLITE_DEFAULT_FILE_PERMISSIONS);
+ terrno = errno;
+ if( fd<0 && errno==ENOENT && islockfile ){
+ if( proxyCreateLockPath(path) == SQLITE_OK ){
+ fd = open(path, openFlags, SQLITE_DEFAULT_FILE_PERMISSIONS);
+ }
+ }
+ }
+ if( fd<0 ){
+ openFlags = O_RDONLY;
+ fd = open(path, openFlags, SQLITE_DEFAULT_FILE_PERMISSIONS);
+ terrno = errno;
+ }
+ if( fd<0 ){
+ if( islockfile ){
+ return SQLITE_BUSY;
+ }
+ switch (terrno) {
+ case EACCES:
+ return SQLITE_PERM;
+ case EIO:
+ return SQLITE_IOERR_LOCK; /* even though it is the conch */
+ default:
+ return SQLITE_CANTOPEN;
+ }
+ }
+
+ pNew = (unixFile *)sqlite3_malloc(sizeof(*pNew));
+ if( pNew==NULL ){
+ rc = SQLITE_NOMEM;
+ goto end_create_proxy;
}
memset(pNew, 0, sizeof(unixFile));
-
- /* Call unixOpen() to open the proxy file. The flags passed to unixOpen()
- ** suggest that the file being opened is a "main database". This is
- ** necessary as other file types do not necessarily support locking. It
- ** is better to use unixOpen() instead of opening the file directly with
- ** open(), as unixOpen() sets up the various mechanisms required to
- ** make sure a call to close() does not cause the system to discard
- ** POSIX locks prematurely.
- **
- ** It is important that the xOpen member of the VFS object passed to
- ** unixOpen() is NULL. This tells unixOpen() may try to open a proxy-file
- ** for the proxy-file (creating a potential infinite loop).
- */
+ pNew->openFlags = openFlags;
dummyVfs.pAppData = (void*)&autolockIoFinder;
- dummyVfs.xOpen = 0;
- rc = unixOpen(&dummyVfs, path, (sqlite3_file *)pNew, flags, &flags);
- if( rc==SQLITE_OK && (flags&SQLITE_OPEN_READONLY) ){
- pNew->pMethod->xClose((sqlite3_file *)pNew);
- rc = SQLITE_CANTOPEN;
+ pUnused->fd = fd;
+ pUnused->flags = openFlags;
+ pNew->pUnused = pUnused;
+
+ rc = fillInUnixFile(&dummyVfs, fd, dirfd, (sqlite3_file*)pNew, path, 0, 0);
+ if( rc==SQLITE_OK ){
+ *ppFile = pNew;
+ return SQLITE_OK;
}
+end_create_proxy:
+ close(fd); /* silently leak fd if error, we're already in error */
+ sqlite3_free(pNew);
+ sqlite3_free(pUnused);
+ return rc;
+}
- if( rc!=SQLITE_OK ){
- sqlite3_free(pNew);
- pNew = 0;
+#ifdef SQLITE_TEST
+/* simulate multiple hosts by creating unique hostid file paths */
+int sqlite3_hostid_num = 0;
+#endif
+
+#define PROXY_HOSTIDLEN 16 /* conch file host id length */
+
+/* get the host ID via gethostuuid(), pHostID must point to PROXY_HOSTIDLEN
+** bytes of writable memory.
+*/
+static int proxyGetHostID(unsigned char *pHostID, int *pError){
+ struct timespec timeout = {1, 0}; /* 1 sec timeout */
+
+ assert(PROXY_HOSTIDLEN == sizeof(uuid_t));
+ memset(pHostID, 0, PROXY_HOSTIDLEN);
+ if( gethostuuid(pHostID, &timeout) ){
+ int err = errno;
+ if( pError ){
+ *pError = err;
+ }
+ return SQLITE_IOERR;
+ }
+#ifdef SQLITE_TEST
+ /* simulate multiple hosts by creating unique hostid file paths */
+ if( sqlite3_hostid_num != 0){
+ pHostID[0] = (char)(pHostID[0] + (char)(sqlite3_hostid_num & 0xFF));
}
+#endif
+
+ return SQLITE_OK;
+}
- *ppFile = pNew;
+/* The conch file contains the header, host id and lock file path
+ */
+#define PROXY_CONCHVERSION 2 /* 1-byte header, 16-byte host id, path */
+#define PROXY_HEADERLEN 1 /* conch file header length */
+#define PROXY_PATHINDEX (PROXY_HEADERLEN+PROXY_HOSTIDLEN)
+#define PROXY_MAXCONCHLEN (PROXY_HEADERLEN+PROXY_HOSTIDLEN+MAXPATHLEN)
+
+/*
+** Takes an open conch file, copies the contents to a new path and then moves
+** it back. The newly created file's file descriptor is assigned to the
+** conch file structure and finally the original conch file descriptor is
+** closed. Returns zero if successful.
+*/
+static int proxyBreakConchLock(unixFile *pFile, uuid_t myHostID){
+ proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+ unixFile *conchFile = pCtx->conchFile;
+ char tPath[MAXPATHLEN];
+ char buf[PROXY_MAXCONCHLEN];
+ char *cPath = pCtx->conchFilePath;
+ size_t readLen = 0;
+ size_t pathLen = 0;
+ char errmsg[64] = "";
+ int fd = -1;
+ int rc = -1;
+
+ /* create a new path by replace the trailing '-conch' with '-break' */
+ pathLen = strlcpy(tPath, cPath, MAXPATHLEN);
+ if( pathLen>MAXPATHLEN || pathLen<6 ||
+ (strlcpy(&tPath[pathLen-5], "break", 6) != 5) ){
+ sprintf(errmsg, "path error (len %d)", (int)pathLen);
+ goto end_breaklock;
+ }
+ /* read the conch content */
+ readLen = pread(conchFile->h, buf, PROXY_MAXCONCHLEN, 0);
+ if( readLen<PROXY_PATHINDEX ){
+ sprintf(errmsg, "read error (len %d)", (int)readLen);
+ goto end_breaklock;
+ }
+ /* write it out to the temporary break file */
+ fd = open(tPath, (O_RDWR|O_CREAT|O_EXCL), SQLITE_DEFAULT_FILE_PERMISSIONS);
+ if( fd<0 ){
+ sprintf(errmsg, "create failed (%d)", errno);
+ goto end_breaklock;
+ }
+ if( pwrite(fd, buf, readLen, 0) != readLen ){
+ sprintf(errmsg, "write failed (%d)", errno);
+ goto end_breaklock;
+ }
+ if( rename(tPath, cPath) ){
+ sprintf(errmsg, "rename failed (%d)", errno);
+ goto end_breaklock;
+ }
+ rc = 0;
+ fprintf(stderr, "broke stale lock on %s\n", cPath);
+ close(conchFile->h);
+ conchFile->h = fd;
+ conchFile->openFlags = O_RDWR | O_CREAT;
+
+end_breaklock:
+ if( rc ){
+ if( fd>=0 ){
+ unlink(tPath);
+ close(fd);
+ }
+ fprintf(stderr, "failed to break stale lock on %s, %s\n", cPath, errmsg);
+ }
+ return rc;
+}
+
+/* Take the requested lock on the conch file and break a stale lock if the
+** host id matches.
+*/
+static int proxyConchLock(unixFile *pFile, uuid_t myHostID, int lockType){
+ proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
+ unixFile *conchFile = pCtx->conchFile;
+ int rc = SQLITE_OK;
+ int nTries = 0;
+ struct timespec conchModTime;
+
+ do {
+ rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+ nTries ++;
+ if( rc==SQLITE_BUSY ){
+ /* If the lock failed (busy):
+ * 1st try: get the mod time of the conch, wait 0.5s and try again.
+ * 2nd try: fail if the mod time changed or host id is different, wait
+ * 10 sec and try again
+ * 3rd try: break the lock unless the mod time has changed.
+ */
+ struct stat buf;
+ if( fstat(conchFile->h, &buf) ){
+ pFile->lastErrno = errno;
+ return SQLITE_IOERR_LOCK;
+ }
+
+ if( nTries==1 ){
+ conchModTime = buf.st_mtimespec;
+ usleep(500000); /* wait 0.5 sec and try the lock again*/
+ continue;
+ }
+
+ assert( nTries>1 );
+ if( conchModTime.tv_sec != buf.st_mtimespec.tv_sec ||
+ conchModTime.tv_nsec != buf.st_mtimespec.tv_nsec ){
+ return SQLITE_BUSY;
+ }
+
+ if( nTries==2 ){
+ char tBuf[PROXY_MAXCONCHLEN];
+ int len = pread(conchFile->h, tBuf, PROXY_MAXCONCHLEN, 0);
+ if( len<0 ){
+ pFile->lastErrno = errno;
+ return SQLITE_IOERR_LOCK;
+ }
+ if( len>PROXY_PATHINDEX && tBuf[0]==(char)PROXY_CONCHVERSION){
+ /* don't break the lock if the host id doesn't match */
+ if( 0!=memcmp(&tBuf[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN) ){
+ return SQLITE_BUSY;
+ }
+ }else{
+ /* don't break the lock on short read or a version mismatch */
+ return SQLITE_BUSY;
+ }
+ usleep(10000000); /* wait 10 sec and try the lock again */
+ continue;
+ }
+
+ assert( nTries==3 );
+ if( 0==proxyBreakConchLock(pFile, myHostID) ){
+ rc = SQLITE_OK;
+ if( lockType==EXCLUSIVE_LOCK ){
+ rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);
+ }
+ if( !rc ){
+ rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);
+ }
+ }
+ }
+ } while( rc==SQLITE_BUSY && nTries<3 );
+
return rc;
}
-/* takes the conch by taking a shared lock and read the contents conch, if
+/* Takes the conch by taking a shared lock and read the contents conch, if
** lockPath is non-NULL, the host ID and lock file path must match. A NULL
** lockPath means that the lockPath in the conch file will be used if the
** host IDs match, or a new lock path will be generated automatically
static int proxyTakeConch(unixFile *pFile){
proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
- if( pCtx->conchHeld>0 ){
+ if( pCtx->conchHeld!=0 ){
return SQLITE_OK;
}else{
unixFile *conchFile = pCtx->conchFile;
- char testValue[CONCHLEN];
- char conchValue[CONCHLEN];
+ uuid_t myHostID;
+ int pError = 0;
+ char readBuf[PROXY_MAXCONCHLEN];
char lockPath[MAXPATHLEN];
- char *tLockPath = NULL;
+ char *tempLockPath = NULL;
int rc = SQLITE_OK;
- int readRc = SQLITE_OK;
- int syncPerms = 0;
-
+ int createConch = 0;
+ int hostIdMatch = 0;
+ int readLen = 0;
+ int tryOldLockPath = 0;
+ int forceNewLockPath = 0;
+
OSTRACE4("TAKECONCH %d for %s pid=%d\n", conchFile->h,
(pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"), getpid());
- rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, SHARED_LOCK);
- if( rc==SQLITE_OK ){
- int pError = 0;
- memset(testValue, 0, CONCHLEN); /* conch is fixed size */
- rc = proxyGetHostID(testValue, &pError);
- if( (rc&0xff)==SQLITE_IOERR ){
- pFile->lastErrno = pError;
- }
- if( pCtx->lockProxyPath ){
- strlcpy(&testValue[HOSTIDLEN], pCtx->lockProxyPath, MAXPATHLEN);
- }
+ rc = proxyGetHostID(myHostID, &pError);
+ if( (rc&0xff)==SQLITE_IOERR ){
+ pFile->lastErrno = pError;
+ goto end_takeconch;
}
+ rc = proxyConchLock(pFile, myHostID, SHARED_LOCK);
if( rc!=SQLITE_OK ){
goto end_takeconch;
}
-
- readRc = unixRead((sqlite3_file *)conchFile, conchValue, CONCHLEN, 0);
- if( readRc!=SQLITE_IOERR_SHORT_READ ){
- if( readRc!=SQLITE_OK ){
- if( (rc&0xff)==SQLITE_IOERR ){
- pFile->lastErrno = conchFile->lastErrno;
+ /* read the existing conch file */
+ readLen = seekAndRead((unixFile*)conchFile, 0, readBuf, PROXY_MAXCONCHLEN);
+ if( readLen<0 ){
+ /* I/O error: lastErrno set by seekAndRead */
+ pFile->lastErrno = conchFile->lastErrno;
+ rc = SQLITE_IOERR_READ;
+ goto end_takeconch;
+ }else if( readLen<=(PROXY_HEADERLEN+PROXY_HOSTIDLEN) ||
+ readBuf[0]!=(char)PROXY_CONCHVERSION ){
+ /* a short read or version format mismatch means we need to create a new
+ ** conch file.
+ */
+ createConch = 1;
+ }
+ /* if the host id matches and the lock path already exists in the conch
+ ** we'll try to use the path there, if we can't open that path, we'll
+ ** retry with a new auto-generated path
+ */
+ do { /* in case we need to try again for an :auto: named lock file */
+
+ if( !createConch && !forceNewLockPath ){
+ hostIdMatch = !memcmp(&readBuf[PROXY_HEADERLEN], myHostID,
+ PROXY_HOSTIDLEN);
+ /* if the conch has data compare the contents */
+ if( !pCtx->lockProxyPath ){
+ /* for auto-named local lock file, just check the host ID and we'll
+ ** use the local lock file path that's already in there
+ */
+ if( hostIdMatch ){
+ size_t pathLen = (readLen - PROXY_PATHINDEX);
+
+ if( pathLen>=MAXPATHLEN ){
+ pathLen=MAXPATHLEN-1;
+ }
+ memcpy(lockPath, &readBuf[PROXY_PATHINDEX], pathLen);
+ lockPath[pathLen] = 0;
+ tempLockPath = lockPath;
+ tryOldLockPath = 1;
+ /* create a copy of the lock path if the conch is taken */
+ goto end_takeconch;
+ }
+ }else if( hostIdMatch
+ && !strncmp(pCtx->lockProxyPath, &readBuf[PROXY_PATHINDEX],
+ readLen-PROXY_PATHINDEX)
+ ){
+ /* conch host and lock path match */
+ goto end_takeconch;
}
- rc = readRc;
+ }
+
+ /* if the conch isn't writable and doesn't match, we can't take it */
+ if( (conchFile->openFlags&O_RDWR) == 0 ){
+ rc = SQLITE_BUSY;
goto end_takeconch;
}
- /* if the conch has data compare the contents */
+
+ /* either the conch didn't match or we need to create a new one */
if( !pCtx->lockProxyPath ){
- /* for auto-named local lock file, just check the host ID and we'll
- ** use the local lock file path that's already in there */
- if( !memcmp(testValue, conchValue, HOSTIDLEN) ){
- tLockPath = (char *)&conchValue[HOSTIDLEN];
- goto end_takeconch;
+ proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
+ tempLockPath = lockPath;
+ /* create a copy of the lock path _only_ if the conch is taken */
+ }
+
+ /* update conch with host and path (this will fail if other process
+ ** has a shared lock already), if the host id matches, use the big
+ ** stick.
+ */
+ futimes(conchFile->h, NULL);
+ if( hostIdMatch && !createConch ){
+ if( conchFile->pLock && conchFile->pLock->cnt>1 ){
+ /* We are trying for an exclusive lock but another thread in this
+ ** same process is still holding a shared lock. */
+ rc = SQLITE_BUSY;
+ } else {
+ rc = proxyConchLock(pFile, myHostID, EXCLUSIVE_LOCK);
}
}else{
- /* we've got the conch if conchValue matches our path and host ID */
- if( !memcmp(testValue, conchValue, CONCHLEN) ){
- goto end_takeconch;
- }
+ rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, EXCLUSIVE_LOCK);
}
- }else{
- /* a short read means we're "creating" the conch (even though it could
- ** have been user-intervention), if we acquire the exclusive lock,
- ** we'll try to match the current on-disk permissions of the database
- */
- syncPerms = 1;
- }
-
- /* either conch was emtpy or didn't match */
- if( !pCtx->lockProxyPath ){
- proxyGetLockPath(pCtx->dbPath, lockPath, MAXPATHLEN);
- tLockPath = lockPath;
- strlcpy(&testValue[HOSTIDLEN], lockPath, MAXPATHLEN);
- }
-
- /* update conch with host and path (this will fail if other process
- ** has a shared lock already) */
- rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, EXCLUSIVE_LOCK);
- if( rc==SQLITE_OK ){
- rc = unixWrite((sqlite3_file *)conchFile, testValue, CONCHLEN, 0);
- if( rc==SQLITE_OK && syncPerms ){
- struct stat buf;
- int err = fstat(pFile->h, &buf);
- if( err==0 ){
- /* try to match the database file permissions, ignore failure */
+ if( rc==SQLITE_OK ){
+ char writeBuffer[PROXY_MAXCONCHLEN];
+ int writeSize = 0;
+
+ writeBuffer[0] = (char)PROXY_CONCHVERSION;
+ memcpy(&writeBuffer[PROXY_HEADERLEN], myHostID, PROXY_HOSTIDLEN);
+ if( pCtx->lockProxyPath!=NULL ){
+ strlcpy(&writeBuffer[PROXY_PATHINDEX], pCtx->lockProxyPath, MAXPATHLEN);
+ }else{
+ strlcpy(&writeBuffer[PROXY_PATHINDEX], tempLockPath, MAXPATHLEN);
+ }
+ writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);
+ ftruncate(conchFile->h, writeSize);
+ rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);
+ fsync(conchFile->h);
+ /* If we created a new conch file (not just updated the contents of a
+ ** valid conch file), try to match the permissions of the database
+ */
+ if( rc==SQLITE_OK && createConch ){
+ struct stat buf;
+ int err = fstat(pFile->h, &buf);
+ if( err==0 ){
+ mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |
+ S_IROTH|S_IWOTH);
+ /* try to match the database file R/W permissions, ignore failure */
#ifndef SQLITE_PROXY_DEBUG
- fchmod(conchFile->h, buf.st_mode);
+ fchmod(conchFile->h, cmode);
#else
- if( fchmod(conchFile->h, buf.st_mode)!=0 ){
+ if( fchmod(conchFile->h, cmode)!=0 ){
+ int code = errno;
+ fprintf(stderr, "fchmod %o FAILED with %d %s\n",
+ cmode, code, strerror(code));
+ } else {
+ fprintf(stderr, "fchmod %o SUCCEDED\n",cmode);
+ }
+ }else{
int code = errno;
- fprintf(stderr, "fchmod %o FAILED with %d %s\n",
- buf.st_mode, code, strerror(code));
- } else {
- fprintf(stderr, "fchmod %o SUCCEDED\n",buf.st_mode);
- }
- }else{
- int code = errno;
- fprintf(stderr, "STAT FAILED[%d] with %d %s\n",
- err, code, strerror(code));
+ fprintf(stderr, "STAT FAILED[%d] with %d %s\n",
+ err, code, strerror(code));
#endif
+ }
}
}
- }
- conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
-
-end_takeconch:
- OSTRACE2("TRANSPROXY: CLOSE %d\n", pFile->h);
- if( rc==SQLITE_OK && pFile->openFlags ){
- if( pFile->h>=0 ){
+ conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, SHARED_LOCK);
+
+ end_takeconch:
+ OSTRACE2("TRANSPROXY: CLOSE %d\n", pFile->h);
+ if( rc==SQLITE_OK && pFile->openFlags ){
+ if( pFile->h>=0 ){
#ifdef STRICT_CLOSE_ERROR
- if( close(pFile->h) ){
- pFile->lastErrno = errno;
- return SQLITE_IOERR_CLOSE;
- }
+ if( close(pFile->h) ){
+ pFile->lastErrno = errno;
+ return SQLITE_IOERR_CLOSE;
+ }
#else
- close(pFile->h); /* silently leak fd if fail */
+ close(pFile->h); /* silently leak fd if fail */
#endif
+ }
+ pFile->h = -1;
+ int fd = open(pCtx->dbPath, pFile->openFlags,
+ SQLITE_DEFAULT_FILE_PERMISSIONS);
+ OSTRACE2("TRANSPROXY: OPEN %d\n", fd);
+ if( fd>=0 ){
+ pFile->h = fd;
+ }else{
+ rc=SQLITE_CANTOPEN; /* SQLITE_BUSY? proxyTakeConch called
+ during locking */
+ }
}
- pFile->h = -1;
- int fd = open(pCtx->dbPath, pFile->openFlags,
- SQLITE_DEFAULT_FILE_PERMISSIONS);
- OSTRACE2("TRANSPROXY: OPEN %d\n", fd);
- if( fd>=0 ){
- pFile->h = fd;
- }else{
- rc=SQLITE_CANTOPEN; /* SQLITE_BUSY? proxyTakeConch called
- during locking */
+ if( rc==SQLITE_OK && !pCtx->lockProxy ){
+ char *path = tempLockPath ? tempLockPath : pCtx->lockProxyPath;
+ rc = proxyCreateUnixFile(path, &pCtx->lockProxy, 1);
+ if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && tryOldLockPath ){
+ /* we couldn't create the proxy lock file with the old lock file path
+ ** so try again via auto-naming
+ */
+ forceNewLockPath = 1;
+ tryOldLockPath = 0;
+ continue; // go back to the do {} while start point, try again
+ }
}
- }
- if( rc==SQLITE_OK && !pCtx->lockProxy ){
- char *path = tLockPath ? tLockPath : pCtx->lockProxyPath;
- /* ACS: Need to make a copy of path sometimes */
- rc = proxyCreateUnixFile(path, &pCtx->lockProxy);
- }
- if( rc==SQLITE_OK ){
- pCtx->conchHeld = 1;
-
- if( tLockPath ){
- pCtx->lockProxyPath = sqlite3DbStrDup(0, tLockPath);
+ if( rc==SQLITE_OK ){
+ /* Need to make a copy of path if we extracted the value
+ ** from the conch file or the path was allocated on the stack
+ */
+ if( tempLockPath ){
+ pCtx->lockProxyPath = sqlite3DbStrDup(0, tempLockPath);
+ if( !pCtx->lockProxyPath ){
+ rc = SQLITE_NOMEM;
+ }
+ }
+ }
+ if( rc==SQLITE_OK ){
+ pCtx->conchHeld = 1;
+
if( pCtx->lockProxy->pMethod == &afpIoMethods ){
- ((afpLockingContext *)pCtx->lockProxy->lockingContext)->dbPath =
- pCtx->lockProxyPath;
+ afpLockingContext *afpCtx;
+ afpCtx = (afpLockingContext *)pCtx->lockProxy->lockingContext;
+ afpCtx->dbPath = pCtx->lockProxyPath;
}
+ } else {
+ conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
}
- } else {
- conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
- }
- OSTRACE3("TAKECONCH %d %s\n", conchFile->h, rc==SQLITE_OK?"ok":"failed");
- return rc;
+ OSTRACE3("TAKECONCH %d %s\n", conchFile->h, rc==SQLITE_OK?"ok":"failed");
+ return rc;
+ } while (1); /* in case we need to retry the :auto: lock file - we should never get here except via the 'continue' call. */
}
}
OSTRACE4("RELEASECONCH %d for %s pid=%d\n", conchFile->h,
(pCtx->lockProxyPath ? pCtx->lockProxyPath : ":auto:"),
getpid());
+ if( pCtx->conchHeld>0 ){
+ rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
+ }
pCtx->conchHeld = 0;
- rc = conchFile->pMethod->xUnlock((sqlite3_file*)conchFile, NO_LOCK);
OSTRACE3("RELEASECONCH %d %s\n", conchFile->h,
(rc==SQLITE_OK ? "ok" : "failed"));
return rc;
/* afp style keeps a reference to the db path in the filePath field
** of the struct */
assert( (int)strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
- strcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath);
- }else
+ strlcpy(dbPath, ((afpLockingContext *)pFile->lockingContext)->dbPath, MAXPATHLEN);
+ } else
#endif
if( pFile->pMethod == &dotlockIoMethods ){
/* dot lock style uses the locking context to store the dot lock
}else{
/* all other styles use the locking context to store the db file path */
assert( strlen((char*)pFile->lockingContext)<=MAXPATHLEN );
- strcpy(dbPath, (char *)pFile->lockingContext);
+ strlcpy(dbPath, (char *)pFile->lockingContext, MAXPATHLEN);
}
return SQLITE_OK;
}
rc = proxyCreateConchPathname(dbPath, &pCtx->conchFilePath);
if( rc==SQLITE_OK ){
- rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile);
+ rc = proxyCreateUnixFile(pCtx->conchFilePath, &pCtx->conchFile, 0);
+ if( rc==SQLITE_CANTOPEN && ((pFile->openFlags&O_RDWR) == 0) ){
+ /* if (a) the open flags are not O_RDWR, (b) the conch isn't there, and
+ ** (c) the file system is read-only, then enable no-locking access.
+ ** Ugh, since O_RDONLY==0x0000 we test for !O_RDWR since unixOpen asserts
+ ** that openFlags will have only one of O_RDONLY or O_RDWR.
+ */
+ struct statfs fsInfo;
+ struct stat conchInfo;
+ int goLockless = 0;
+
+ if( stat(pCtx->conchFilePath, &conchInfo) == -1 ) {
+ int err = errno;
+ if( (err==ENOENT) && (statfs(dbPath, &fsInfo) != -1) ){
+ goLockless = (fsInfo.f_flags&MNT_RDONLY) == MNT_RDONLY;
+ }
+ }
+ if( goLockless ){
+ pCtx->conchHeld = -1; /* read only FS/ lockless */
+ rc = SQLITE_OK;
+ }
+ }
}
if( rc==SQLITE_OK && lockPath ){
pCtx->lockProxyPath = sqlite3DbStrDup(0, lockPath);
}
+ if( rc==SQLITE_OK ){
+ pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
+ if( pCtx->dbPath==NULL ){
+ rc = SQLITE_NOMEM;
+ }
+ }
if( rc==SQLITE_OK ){
/* all memory is allocated, proxys are created and assigned,
** switch the locking context and pMethod then return.
*/
- pCtx->dbPath = sqlite3DbStrDup(0, dbPath);
pCtx->oldLockingContext = pFile->lockingContext;
pFile->lockingContext = pCtx;
pCtx->pOldMethod = pFile->pMethod;
pFile->pMethod = &proxyIoMethods;
}else{
if( pCtx->conchFile ){
- rc = pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
- if( rc ) return rc;
+ pCtx->conchFile->pMethod->xClose((sqlite3_file *)pCtx->conchFile);
sqlite3_free(pCtx->conchFile);
}
+ sqlite3_free(pCtx->lockProxyPath);
sqlite3_free(pCtx->conchFilePath);
sqlite3_free(pCtx);
}
int rc = proxyTakeConch(pFile);
if( rc==SQLITE_OK ){
proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
- unixFile *proxy = pCtx->lockProxy;
- return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
+ if( pCtx->conchHeld>0 ){
+ unixFile *proxy = pCtx->lockProxy;
+ return proxy->pMethod->xCheckReservedLock((sqlite3_file*)proxy, pResOut);
+ }else{ /* conchHeld < 0 is lockless */
+ pResOut=0;
+ }
}
return rc;
}
int rc = proxyTakeConch(pFile);
if( rc==SQLITE_OK ){
proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
- unixFile *proxy = pCtx->lockProxy;
- rc = proxy->pMethod->xLock((sqlite3_file*)proxy, locktype);
- pFile->locktype = proxy->locktype;
+ if( pCtx->conchHeld>0 ){
+ unixFile *proxy = pCtx->lockProxy;
+ rc = proxy->pMethod->xLock((sqlite3_file*)proxy, locktype);
+ pFile->locktype = proxy->locktype;
+ }else{
+ /* conchHeld < 0 is lockless */
+ }
}
return rc;
}
int rc = proxyTakeConch(pFile);
if( rc==SQLITE_OK ){
proxyLockingContext *pCtx = (proxyLockingContext *)pFile->lockingContext;
- unixFile *proxy = pCtx->lockProxy;
- rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, locktype);
- pFile->locktype = proxy->locktype;
+ if( pCtx->conchHeld>0 ){
+ unixFile *proxy = pCtx->lockProxy;
+ rc = proxy->pMethod->xUnlock((sqlite3_file*)proxy, locktype);
+ pFile->locktype = proxy->locktype;
+ }else{
+ /* conchHeld < 0 is lockless */
+ }
}
return rc;
}
#endif
UNIXVFS("unix-none", nolockIoFinder ),
UNIXVFS("unix-dotfile", dotlockIoFinder ),
- UNIXVFS("unix-wfl", posixWflIoFinder ),
#if OS_VXWORKS
UNIXVFS("unix-namedsem", semIoFinder ),
#endif
#endif
#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)
UNIXVFS("unix-afp", afpIoFinder ),
+ UNIXVFS("unix-nfs", nfsIoFinder ),
UNIXVFS("unix-proxy", proxyIoFinder ),
#endif
};
projects / thirdparty / sqlite.git / commitdiff
