DBD-SQLite2
view release on metacpan or search on metacpan
#define TRACE2(X,Y) fprintf(stderr,X,Y)
#define TRACE3(X,Y,Z) fprintf(stderr,X,Y,Z)
#define TRACE4(X,Y,Z,A) fprintf(stderr,X,Y,Z,A)
#define TRACE5(X,Y,Z,A,B) fprintf(stderr,X,Y,Z,A,B)
#else
#define TIMER_START
#define TIMER_END
#define SEEK(X)
#define TRACE1(X)
#define TRACE2(X,Y)
#define TRACE3(X,Y,Z)
#define TRACE4(X,Y,Z,A)
#define TRACE5(X,Y,Z,A,B)
#endif
#if OS_UNIX
/*
** Here is the dirt on POSIX advisory locks: ANSI STD 1003.1 (1996)
** section 6.5.2.2 lines 483 through 490 specify that when a process
** sets or clears a lock, that operation overrides any prior locks set
** by the same process. It does not explicitly say so, but this implies
** that it overrides locks set by the same process using a different
** file descriptor. Consider this test case:
**
** int fd1 = open("./file1", O_RDWR|O_CREAT, 0644);
** int fd2 = open("./file2", O_RDWR|O_CREAT, 0644);
**
** Suppose ./file1 and ./file2 are really the same file (because
** one is a hard or symbolic link to the other) then if you set
** an exclusive lock on fd1, then try to get an exclusive lock
** on fd2, it works. I would have expected the second lock to
** fail since there was already a lock on the file due to fd1.
** But not so. Since both locks came from the same process, the
** second overrides the first, even though they were on different
** file descriptors opened on different file names.
**
** Bummer. If you ask me, this is broken. Badly broken. It means
** that we cannot use POSIX locks to synchronize file access among
** competing threads of the same process. POSIX locks will work fine
** to synchronize access for threads in separate processes, but not
** threads within the same process.
**
** To work around the problem, SQLite has to manage file locks internally
** on its own. Whenever a new database is opened, we have to find the
** specific inode of the database file (the inode is determined by the
** st_dev and st_ino fields of the stat structure that fstat() fills in)
** and check for locks already existing on that inode. When locks are
** created or removed, we have to look at our own internal record of the
** locks to see if another thread has previously set a lock on that same
** inode.
**
** The OsFile structure for POSIX is no longer just an integer file
** descriptor. It is now a structure that holds the integer file
** descriptor and a pointer to a structure that describes the internal
** locks on the corresponding inode. There is one locking structure
** per inode, so if the same inode is opened twice, both OsFile structures
** point to the same locking structure. The locking structure keeps
** a reference count (so we will know when to delete it) and a "cnt"
** field that tells us its internal lock status. cnt==0 means the
** file is unlocked. cnt==-1 means the file has an exclusive lock.
** cnt>0 means there are cnt shared locks on the file.
**
** Any attempt to lock or unlock a file first checks the locking
** structure. The fcntl() system call is only invoked to set a
** POSIX lock if the internal lock structure transitions between
** a locked and an unlocked state.
**
** 2004-Jan-11:
** More recent discoveries about POSIX advisory locks. (The more
** I discover, the more I realize the a POSIX advisory locks are
** an abomination.)
**
** If you close a file descriptor that points to a file that has locks,
** all locks on that file that are owned by the current process are
** released. To work around this problem, each OsFile structure contains
** a pointer to an openCnt structure. There is one openCnt structure
** per open inode, which means that multiple OsFiles can point to a single
** openCnt. When an attempt is made to close an OsFile, if there are
** other OsFiles open on the same inode that are holding locks, the call
** to close() the file descriptor is deferred until all of the locks clear.
** The openCnt structure keeps a list of file descriptors that need to
** be closed and that list is walked (and cleared) when the last lock
** clears.
**
** First, under Linux threads, because each thread has a separate
** process ID, lock operations in one thread do not override locks
** to the same file in other threads. Linux threads behave like
** separate processes in this respect. But, if you close a file
** descriptor in linux threads, all locks are cleared, even locks
** on other threads and even though the other threads have different
** process IDs. Linux threads is inconsistent in this respect.
** (I'm beginning to think that linux threads is an abomination too.)
** The consequence of this all is that the hash table for the lockInfo
** structure has to include the process id as part of its key because
** locks in different threads are treated as distinct. But the
** openCnt structure should not include the process id in its
** key because close() clears lock on all threads, not just the current
** thread. Were it not for this goofiness in linux threads, we could
** combine the lockInfo and openCnt structures into a single structure.
*/
/*
** An instance of the following structure serves as the key used
** to locate a particular lockInfo structure given its inode. Note
** that we have to include the process ID as part of the key. On some
** threading implementations (ex: linux), each thread has a separate
** process ID.
*/
struct lockKey {
dev_t dev; /* Device number */
ino_t ino; /* Inode number */
pid_t pid; /* Process ID */
};
/*
** An instance of the following structure is allocated for each open
** inode on each thread with a different process ID. (Threads have
** different process IDs on linux, but not on most other unixes.)
**
** A single inode can have multiple file descriptors, so each OsFile
** structure contains a pointer to an instance of this object and this
** object keeps a count of the number of OsFiles pointing to it.
*/
struct lockInfo {
struct lockKey key; /* The lookup key */
int cnt; /* 0: unlocked. -1: write lock. 1...: read lock. */
int nRef; /* Number of pointers to this structure */
};
/*
** An instance of the following structure serves as the key used
** to locate a particular openCnt structure given its inode. This
** is the same as the lockKey except that the process ID is omitted.
*/
struct openKey {
dev_t dev; /* Device number */
ino_t ino; /* Inode number */
};
/*
** An instance of the following structure is allocated for each open
** inode. This structure keeps track of the number of locks on that
** inode. If a close is attempted against an inode that is holding
** locks, the close is deferred until all locks clear by adding the
** file descriptor to be closed to the pending list.
*/
struct openCnt {
struct openKey key; /* The lookup key */
int nRef; /* Number of pointers to this structure */
int nLock; /* Number of outstanding locks */
int nPending; /* Number of pending close() operations */
int *aPending; /* Malloced space holding fd's awaiting a close() */
};
/*
** These hash table maps inodes and process IDs into lockInfo and openCnt
** structures. Access to these hash tables must be protected by a mutex.
*/
static Hash lockHash = { SQLITE_HASH_BINARY, 0, 0, 0, 0, 0 };
static Hash openHash = { SQLITE_HASH_BINARY, 0, 0, 0, 0, 0 };
/*
** Release a lockInfo structure previously allocated by findLockInfo().
*/
static void releaseLockInfo(struct lockInfo *pLock){
pLock->nRef--;
if( pLock->nRef==0 ){
sqliteHashInsert(&lockHash, &pLock->key, sizeof(pLock->key), 0);
sqliteFree(pLock);
}
}
/*
** Release a openCnt structure previously allocated by findLockInfo().
*/
static void releaseOpenCnt(struct openCnt *pOpen){
pOpen->nRef--;
if( pOpen->nRef==0 ){
sqliteHashInsert(&openHash, &pOpen->key, sizeof(pOpen->key), 0);
sqliteFree(pOpen->aPending);
sqliteFree(pOpen);
}
}
/*
** Given a file descriptor, locate lockInfo and openCnt structures that
}
unlink(zOldName);
return SQLITE_OK;
#endif
#if OS_WIN
if( !MoveFile(zOldName, zNewName) ){
return SQLITE_ERROR;
}
return SQLITE_OK;
#endif
#if OS_MAC
/**** FIX ME ***/
return SQLITE_ERROR;
#endif
}
#endif /* NOT USED */
/*
** Attempt to open a file for both reading and writing. If that
** fails, try opening it read-only. If the file does not exist,
** try to create it.
**
** On success, a handle for the open file is written to *id
** and *pReadonly is set to 0 if the file was opened for reading and
** writing or 1 if the file was opened read-only. The function returns
** SQLITE_OK.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id and *pReadonly unchanged.
*/
int sqliteOsOpenReadWrite(
const char *zFilename,
OsFile *id,
int *pReadonly
){
#if OS_UNIX
int rc;
id->dirfd = -1;
id->fd = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY, 0644);
if( id->fd<0 ){
#ifdef EISDIR
if( errno==EISDIR ){
return SQLITE_CANTOPEN;
}
#endif
id->fd = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
if( id->fd<0 ){
return SQLITE_CANTOPEN;
}
*pReadonly = 1;
}else{
*pReadonly = 0;
}
sqliteOsEnterMutex();
rc = findLockInfo(id->fd, &id->pLock, &id->pOpen);
sqliteOsLeaveMutex();
if( rc ){
close(id->fd);
return SQLITE_NOMEM;
}
id->locked = 0;
TRACE3("OPEN %-3d %s\n", id->fd, zFilename);
OpenCounter(+1);
return SQLITE_OK;
#endif
#if OS_WIN
HANDLE h = CreateFile(zFilename,
GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE,
NULL,
OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
NULL
);
if( h==INVALID_HANDLE_VALUE ){
h = CreateFile(zFilename,
GENERIC_READ,
FILE_SHARE_READ,
NULL,
OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
NULL
);
if( h==INVALID_HANDLE_VALUE ){
return SQLITE_CANTOPEN;
}
*pReadonly = 1;
}else{
*pReadonly = 0;
}
id->h = h;
id->locked = 0;
OpenCounter(+1);
return SQLITE_OK;
#endif
#if OS_MAC
FSSpec fsSpec;
# ifdef _LARGE_FILE
HFSUniStr255 dfName;
FSRef fsRef;
if( __path2fss(zFilename, &fsSpec) != noErr ){
if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr )
return SQLITE_CANTOPEN;
}
if( FSpMakeFSRef(&fsSpec, &fsRef) != noErr )
return SQLITE_CANTOPEN;
FSGetDataForkName(&dfName);
if( FSOpenFork(&fsRef, dfName.length, dfName.unicode,
fsRdWrShPerm, &(id->refNum)) != noErr ){
if( FSOpenFork(&fsRef, dfName.length, dfName.unicode,
fsRdWrPerm, &(id->refNum)) != noErr ){
if (FSOpenFork(&fsRef, dfName.length, dfName.unicode,
fsRdPerm, &(id->refNum)) != noErr )
return SQLITE_CANTOPEN;
else
*pReadonly = 1;
} else
*pReadonly = 0;
} else
*pReadonly = 0;
# else
__path2fss(zFilename, &fsSpec);
if( !sqliteOsFileExists(zFilename) ){
if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr )
return SQLITE_CANTOPEN;
}
if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrShPerm, &(id->refNum)) != noErr ){
if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrPerm, &(id->refNum)) != noErr ){
if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdPerm, &(id->refNum)) != noErr )
return SQLITE_CANTOPEN;
else
*pReadonly = 1;
} else
*pReadonly = 0;
} else
*pReadonly = 0;
# endif
if( HOpenRF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrShPerm, &(id->refNumRF)) != noErr){
id->refNumRF = -1;
}
id->locked = 0;
id->delOnClose = 0;
OpenCounter(+1);
return SQLITE_OK;
#endif
}
/*
** Attempt to open a new file for exclusive access by this process.
** The file will be opened for both reading and writing. To avoid
** a potential security problem, we do not allow the file to have
** previously existed. Nor do we allow the file to be a symbolic
** link.
**
** If delFlag is true, then make arrangements to automatically delete
** the file when it is closed.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
int sqliteOsOpenExclusive(const char *zFilename, OsFile *id, int delFlag){
#if OS_UNIX
int rc;
if( access(zFilename, 0)==0 ){
return SQLITE_CANTOPEN;
}
id->dirfd = -1;
id->fd = open(zFilename,
O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY, 0600);
if( id->fd<0 ){
return SQLITE_CANTOPEN;
}
sqliteOsEnterMutex();
rc = findLockInfo(id->fd, &id->pLock, &id->pOpen);
sqliteOsLeaveMutex();
if( rc ){
close(id->fd);
unlink(zFilename);
return SQLITE_NOMEM;
}
id->locked = 0;
if( delFlag ){
unlink(zFilename);
}
TRACE3("OPEN-EX %-3d %s\n", id->fd, zFilename);
OpenCounter(+1);
return SQLITE_OK;
#endif
#if OS_WIN
HANDLE h;
int fileflags;
if( delFlag ){
fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS
| FILE_FLAG_DELETE_ON_CLOSE;
}else{
fileflags = FILE_FLAG_RANDOM_ACCESS;
}
h = CreateFile(zFilename,
GENERIC_READ | GENERIC_WRITE,
0,
NULL,
CREATE_ALWAYS,
fileflags,
NULL
);
if( h==INVALID_HANDLE_VALUE ){
return SQLITE_CANTOPEN;
}
id->h = h;
id->locked = 0;
OpenCounter(+1);
return SQLITE_OK;
#endif
#if OS_MAC
FSSpec fsSpec;
# ifdef _LARGE_FILE
HFSUniStr255 dfName;
FSRef fsRef;
__path2fss(zFilename, &fsSpec);
if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr )
return SQLITE_CANTOPEN;
if( FSpMakeFSRef(&fsSpec, &fsRef) != noErr )
return SQLITE_CANTOPEN;
FSGetDataForkName(&dfName);
if( FSOpenFork(&fsRef, dfName.length, dfName.unicode,
fsRdWrPerm, &(id->refNum)) != noErr )
return SQLITE_CANTOPEN;
# else
__path2fss(zFilename, &fsSpec);
if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr )
return SQLITE_CANTOPEN;
if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrPerm, &(id->refNum)) != noErr )
return SQLITE_CANTOPEN;
# endif
id->refNumRF = -1;
id->locked = 0;
id->delOnClose = delFlag;
if (delFlag)
id->pathToDel = sqliteOsFullPathname(zFilename);
OpenCounter(+1);
return SQLITE_OK;
#endif
}
/*
** Attempt to open a new file for read-only access.
**
** On success, write the file handle into *id and return SQLITE_OK.
**
** On failure, return SQLITE_CANTOPEN.
*/
int sqliteOsOpenReadOnly(const char *zFilename, OsFile *id){
#if OS_UNIX
int rc;
id->dirfd = -1;
id->fd = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
if( id->fd<0 ){
return SQLITE_CANTOPEN;
}
sqliteOsEnterMutex();
rc = findLockInfo(id->fd, &id->pLock, &id->pOpen);
sqliteOsLeaveMutex();
if( rc ){
close(id->fd);
return SQLITE_NOMEM;
}
id->locked = 0;
TRACE3("OPEN-RO %-3d %s\n", id->fd, zFilename);
OpenCounter(+1);
return SQLITE_OK;
#endif
#if OS_WIN
HANDLE h = CreateFile(zFilename,
GENERIC_READ,
0,
NULL,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS,
NULL
);
if( h==INVALID_HANDLE_VALUE ){
return SQLITE_CANTOPEN;
}
id->h = h;
id->locked = 0;
OpenCounter(+1);
return SQLITE_OK;
#endif
#if OS_MAC
FSSpec fsSpec;
# ifdef _LARGE_FILE
HFSUniStr255 dfName;
FSRef fsRef;
if( __path2fss(zFilename, &fsSpec) != noErr )
return SQLITE_CANTOPEN;
if( FSpMakeFSRef(&fsSpec, &fsRef) != noErr )
return SQLITE_CANTOPEN;
FSGetDataForkName(&dfName);
if( FSOpenFork(&fsRef, dfName.length, dfName.unicode,
fsRdPerm, &(id->refNum)) != noErr )
return SQLITE_CANTOPEN;
# else
__path2fss(zFilename, &fsSpec);
if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdPerm, &(id->refNum)) != noErr )
return SQLITE_CANTOPEN;
# endif
if( HOpenRF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrShPerm, &(id->refNumRF)) != noErr){
id->refNumRF = -1;
}
id->locked = 0;
id->delOnClose = 0;
OpenCounter(+1);
return SQLITE_OK;
#endif
}
/*
** Attempt to open a file descriptor for the directory that contains a
** file. This file descriptor can be used to fsync() the directory
** in order to make sure the creation of a new file is actually written
** to disk.
**
** This routine is only meaningful for Unix. It is a no-op under
** windows since windows does not support hard links.
**
** On success, a handle for a previously open file is at *id is
** updated with the new directory file descriptor and SQLITE_OK is
** returned.
**
** On failure, the function returns SQLITE_CANTOPEN and leaves
** *id unchanged.
*/
int sqliteOsOpenDirectory(
const char *zDirname,
OsFile *id
){
#if OS_UNIX
if( id->fd<0 ){
/* Do not open the directory if the corresponding file is not already
** open. */
return SQLITE_CANTOPEN;
}
assert( id->dirfd<0 );
id->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0644);
if( id->dirfd<0 ){
return SQLITE_CANTOPEN;
}
TRACE3("OPENDIR %-3d %s\n", id->dirfd, zDirname);
#endif
return SQLITE_OK;
}
/*
** If the following global variable points to a string which is the
** name of a directory, then that directory will be used to store
** temporary files.
*/
const char *sqlite_temp_directory = 0;
/*
** Create a temporary file name in zBuf. zBuf must be big enough to
** hold at least SQLITE_TEMPNAME_SIZE characters.
*/
int sqliteOsTempFileName(char *zBuf){
#if OS_UNIX
static const char *azDirs[] = {
0,
"/var/tmp",
"/usr/tmp",
"/tmp",
osType = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1;
}
return osType==2;
}
#endif
/*
** Windows file locking notes: [similar issues apply to MacOS]
**
** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because
** those functions are not available. So we use only LockFile() and
** UnlockFile().
**
** LockFile() prevents not just writing but also reading by other processes.
** (This is a design error on the part of Windows, but there is nothing
** we can do about that.) So the region used for locking is at the
** end of the file where it is unlikely to ever interfere with an
** actual read attempt.
**
** A database read lock is obtained by locking a single randomly-chosen
** byte out of a specific range of bytes. The lock byte is obtained at
** random so two separate readers can probably access the file at the
** same time, unless they are unlucky and choose the same lock byte.
** A database write lock is obtained by locking all bytes in the range.
** There can only be one writer.
**
** A lock is obtained on the first byte of the lock range before acquiring
** either a read lock or a write lock. This prevents two processes from
** attempting to get a lock at a same time. The semantics of
** sqliteOsReadLock() require that if there is already a write lock, that
** lock is converted into a read lock atomically. The lock on the first
** byte allows us to drop the old write lock and get the read lock without
** another process jumping into the middle and messing us up. The same
** argument applies to sqliteOsWriteLock().
**
** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available,
** which means we can use reader/writer locks. When reader writer locks
** are used, the lock is placed on the same range of bytes that is used
** for probabilistic locking in Win95/98/ME. Hence, the locking scheme
** will support two or more Win95 readers or two or more WinNT readers.
** But a single Win95 reader will lock out all WinNT readers and a single
** WinNT reader will lock out all other Win95 readers.
**
** Note: On MacOS we use the resource fork for locking.
**
** The following #defines specify the range of bytes used for locking.
** N_LOCKBYTE is the number of bytes available for doing the locking.
** The first byte used to hold the lock while the lock is changing does
** not count toward this number. FIRST_LOCKBYTE is the address of
** the first byte in the range of bytes used for locking.
*/
#define N_LOCKBYTE 10239
#if OS_MAC
# define FIRST_LOCKBYTE (0x000fffff - N_LOCKBYTE)
#else
# define FIRST_LOCKBYTE (0xffffffff - N_LOCKBYTE)
#endif
/*
** Change the status of the lock on the file "id" to be a readlock.
** If the file was write locked, then this reduces the lock to a read.
** If the file was read locked, then this acquires a new read lock.
**
** Return SQLITE_OK on success and SQLITE_BUSY on failure. If this
** library was compiled with large file support (LFS) but LFS is not
** available on the host, then an SQLITE_NOLFS is returned.
*/
int sqliteOsReadLock(OsFile *id){
#if OS_UNIX
int rc;
sqliteOsEnterMutex();
if( id->pLock->cnt>0 ){
if( !id->locked ){
id->pLock->cnt++;
id->locked = 1;
id->pOpen->nLock++;
}
rc = SQLITE_OK;
}else if( id->locked || id->pLock->cnt==0 ){
struct flock lock;
int s;
lock.l_type = F_RDLCK;
lock.l_whence = SEEK_SET;
lock.l_start = lock.l_len = 0L;
s = fcntl(id->fd, F_SETLK, &lock);
if( s!=0 ){
rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
}else{
rc = SQLITE_OK;
if( !id->locked ){
id->pOpen->nLock++;
id->locked = 1;
}
id->pLock->cnt = 1;
}
}else{
rc = SQLITE_BUSY;
}
sqliteOsLeaveMutex();
return rc;
#endif
#if OS_WIN
int rc;
if( id->locked>0 ){
rc = SQLITE_OK;
}else{
int lk;
int res;
int cnt = 100;
sqliteRandomness(sizeof(lk), &lk);
lk = (lk & 0x7fffffff)%N_LOCKBYTE + 1;
while( cnt-->0 && (res = LockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0))==0 ){
Sleep(1);
}
if( res ){
UnlockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0);
if( isNT() ){
OVERLAPPED ovlp;
ovlp.Offset = FIRST_LOCKBYTE+1;
ovlp.OffsetHigh = 0;
ovlp.hEvent = 0;
res = LockFileEx(id->h, LOCKFILE_FAIL_IMMEDIATELY,
0, N_LOCKBYTE, 0, &ovlp);
}else{
res = LockFile(id->h, FIRST_LOCKBYTE+lk, 0, 1, 0);
}
UnlockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0);
}
if( res ){
id->locked = lk;
rc = SQLITE_OK;
}else{
rc = SQLITE_BUSY;
}
}
return rc;
#endif
#if OS_MAC
int rc;
if( id->locked>0 || id->refNumRF == -1 ){
rc = SQLITE_OK;
}else{
int lk;
OSErr res;
int cnt = 5;
ParamBlockRec params;
sqliteRandomness(sizeof(lk), &lk);
lk = (lk & 0x7fffffff)%N_LOCKBYTE + 1;
memset(¶ms, 0, sizeof(params));
params.ioParam.ioRefNum = id->refNumRF;
params.ioParam.ioPosMode = fsFromStart;
params.ioParam.ioPosOffset = FIRST_LOCKBYTE;
params.ioParam.ioReqCount = 1;
while( cnt-->0 && (res = PBLockRangeSync(¶ms))!=noErr ){
UInt32 finalTicks;
Delay(1, &finalTicks); /* 1/60 sec */
}
if( res == noErr ){
params.ioParam.ioPosOffset = FIRST_LOCKBYTE+1;
params.ioParam.ioReqCount = N_LOCKBYTE;
PBUnlockRangeSync(¶ms);
params.ioParam.ioPosOffset = FIRST_LOCKBYTE+lk;
params.ioParam.ioReqCount = 1;
res = PBLockRangeSync(¶ms);
params.ioParam.ioPosOffset = FIRST_LOCKBYTE;
params.ioParam.ioReqCount = 1;
PBUnlockRangeSync(¶ms);
}
if( res == noErr ){
id->locked = lk;
rc = SQLITE_OK;
}else{
rc = SQLITE_BUSY;
}
}
return rc;
#endif
}
/*
** Change the lock status to be an exclusive or write lock. Return
** SQLITE_OK on success and SQLITE_BUSY on a failure. If this
** library was compiled with large file support (LFS) but LFS is not
** available on the host, then an SQLITE_NOLFS is returned.
*/
int sqliteOsWriteLock(OsFile *id){
#if OS_UNIX
int rc;
sqliteOsEnterMutex();
if( id->pLock->cnt==0 || (id->pLock->cnt==1 && id->locked==1) ){
struct flock lock;
int s;
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = lock.l_len = 0L;
s = fcntl(id->fd, F_SETLK, &lock);
if( s!=0 ){
rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
}else{
rc = SQLITE_OK;
if( !id->locked ){
id->pOpen->nLock++;
id->locked = 1;
}
id->pLock->cnt = -1;
}
}else{
rc = SQLITE_BUSY;
}
sqliteOsLeaveMutex();
return rc;
#endif
#if OS_WIN
int rc;
if( id->locked<0 ){
rc = SQLITE_OK;
}else{
int res;
int cnt = 100;
while( cnt-->0 && (res = LockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0))==0 ){
Sleep(1);
}
if( res ){
if( id->locked>0 ){
if( isNT() ){
UnlockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0);
}else{
res = UnlockFile(id->h, FIRST_LOCKBYTE + id->locked, 0, 1, 0);
}
}
if( res ){
res = LockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0);
}else{
res = 0;
}
UnlockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0);
}
if( res ){
id->locked = -1;
rc = SQLITE_OK;
}else{
rc = SQLITE_BUSY;
}
}
return rc;
#endif
#if OS_MAC
int rc;
if( id->locked<0 || id->refNumRF == -1 ){
rc = SQLITE_OK;
}else{
OSErr res;
int cnt = 5;
ParamBlockRec params;
memset(¶ms, 0, sizeof(params));
params.ioParam.ioRefNum = id->refNumRF;
params.ioParam.ioPosMode = fsFromStart;
params.ioParam.ioPosOffset = FIRST_LOCKBYTE;
params.ioParam.ioReqCount = 1;
while( cnt-->0 && (res = PBLockRangeSync(¶ms))!=noErr ){
UInt32 finalTicks;
Delay(1, &finalTicks); /* 1/60 sec */
}
if( res == noErr ){
params.ioParam.ioPosOffset = FIRST_LOCKBYTE + id->locked;
params.ioParam.ioReqCount = 1;
if( id->locked==0
|| PBUnlockRangeSync(¶ms)==noErr ){
params.ioParam.ioPosOffset = FIRST_LOCKBYTE+1;
params.ioParam.ioReqCount = N_LOCKBYTE;
res = PBLockRangeSync(¶ms);
}else{
res = afpRangeNotLocked;
}
params.ioParam.ioPosOffset = FIRST_LOCKBYTE;
params.ioParam.ioReqCount = 1;
PBUnlockRangeSync(¶ms);
}
if( res == noErr ){
id->locked = -1;
rc = SQLITE_OK;
}else{
rc = SQLITE_BUSY;
}
}
return rc;
#endif
}
/*
** Unlock the given file descriptor. If the file descriptor was
** not previously locked, then this routine is a no-op. If this
** library was compiled with large file support (LFS) but LFS is not
** available on the host, then an SQLITE_NOLFS is returned.
*/
int sqliteOsUnlock(OsFile *id){
#if OS_UNIX
int rc;
if( !id->locked ) return SQLITE_OK;
sqliteOsEnterMutex();
assert( id->pLock->cnt!=0 );
if( id->pLock->cnt>1 ){
id->pLock->cnt--;
rc = SQLITE_OK;
}else{
struct flock lock;
int s;
lock.l_type = F_UNLCK;
lock.l_whence = SEEK_SET;
lock.l_start = lock.l_len = 0L;
s = fcntl(id->fd, F_SETLK, &lock);
if( s!=0 ){
rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY;
}else{
rc = SQLITE_OK;
id->pLock->cnt = 0;
}
}
if( rc==SQLITE_OK ){
/* Decrement the count of locks against this same file. When the
** count reaches zero, close any other file descriptors whose close
** was deferred because of outstanding locks.
*/
struct openCnt *pOpen = id->pOpen;
pOpen->nLock--;
assert( pOpen->nLock>=0 );
if( pOpen->nLock==0 && pOpen->nPending>0 ){
int i;
for(i=0; i<pOpen->nPending; i++){
close(pOpen->aPending[i]);
}
sqliteFree(pOpen->aPending);
pOpen->nPending = 0;
pOpen->aPending = 0;
}
}
sqliteOsLeaveMutex();
id->locked = 0;
return rc;
#endif
#if OS_WIN
int rc;
if( id->locked==0 ){
rc = SQLITE_OK;
}else if( isNT() || id->locked<0 ){
UnlockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0);
rc = SQLITE_OK;
id->locked = 0;
}else{
UnlockFile(id->h, FIRST_LOCKBYTE+id->locked, 0, 1, 0);
rc = SQLITE_OK;
id->locked = 0;
}
return rc;
#endif
#if OS_MAC
int rc;
ParamBlockRec params;
memset(¶ms, 0, sizeof(params));
params.ioParam.ioRefNum = id->refNumRF;
params.ioParam.ioPosMode = fsFromStart;
if( id->locked==0 || id->refNumRF == -1 ){
rc = SQLITE_OK;
}else if( id->locked<0 ){
params.ioParam.ioPosOffset = FIRST_LOCKBYTE+1;
params.ioParam.ioReqCount = N_LOCKBYTE;
PBUnlockRangeSync(¶ms);
rc = SQLITE_OK;
id->locked = 0;
}else{
params.ioParam.ioPosOffset = FIRST_LOCKBYTE+id->locked;
params.ioParam.ioReqCount = 1;
PBUnlockRangeSync(¶ms);
rc = SQLITE_OK;
id->locked = 0;
}
return rc;
#endif
}
/*
** Get information to seed the random number generator. The seed
** is written into the buffer zBuf[256]. The calling function must
** supply a sufficiently large buffer.
*/
int sqliteOsRandomSeed(char *zBuf){
/* We have to initialize zBuf to prevent valgrind from reporting
** errors. The reports issued by valgrind are incorrect - we would
** prefer that the randomness be increased by making use of the
** uninitialized space in zBuf - but valgrind errors tend to worry
** some users. Rather than argue, it seems easier just to initialize
** the whole array and silence valgrind, even if that means less randomness
** in the random seed.
**
** When testing, initializing zBuf[] to zero is all we do. That means
** that we always use the same random number sequence.* This makes the
** tests repeatable.
*/
memset(zBuf, 0, 256);
#if OS_UNIX && !defined(SQLITE_TEST)
{
int pid;
time((time_t*)zBuf);
pid = getpid();
memcpy(&zBuf[sizeof(time_t)], &pid, sizeof(pid));
}
#endif
#if OS_WIN && !defined(SQLITE_TEST)
GetSystemTime((LPSYSTEMTIME)zBuf);
#endif
#if OS_MAC
{
int pid;
Microseconds((UnsignedWide*)zBuf);
pid = getpid();
memcpy(&zBuf[sizeof(UnsignedWide)], &pid, sizeof(pid));
}
#endif
return SQLITE_OK;
}
/*
** Sleep for a little while. Return the amount of time slept.
*/
int sqliteOsSleep(int ms){
#if OS_UNIX
#if defined(HAVE_USLEEP) && HAVE_USLEEP
usleep(ms*1000);
return ms;
#else
sleep((ms+999)/1000);
return 1000*((ms+999)/1000);
#endif
#endif
#if OS_WIN
Sleep(ms);
return ms;
#endif
#if OS_MAC
UInt32 finalTicks;
UInt32 ticks = (((UInt32)ms+16)*3)/50; /* 1/60 sec per tick */
Delay(ticks, &finalTicks);
return (int)((ticks*50)/3);
#endif
}
/*
** Static variables used for thread synchronization
*/
static int inMutex = 0;
#ifdef SQLITE_UNIX_THREADS
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
#ifdef SQLITE_W32_THREADS
static CRITICAL_SECTION cs;
#endif
#ifdef SQLITE_MACOS_MULTITASKING
static MPCriticalRegionID criticalRegion;
#endif
/*
** The following pair of routine implement mutual exclusion for
** multi-threaded processes. Only a single thread is allowed to
** executed code that is surrounded by EnterMutex() and LeaveMutex().
**
** SQLite uses only a single Mutex. There is not much critical
** code and what little there is executes quickly and without blocking.
*/
void sqliteOsEnterMutex(){
#ifdef SQLITE_UNIX_THREADS
pthread_mutex_lock(&mutex);
#endif
#ifdef SQLITE_W32_THREADS
static int isInit = 0;
while( !isInit ){
static long lock = 0;
if( InterlockedIncrement(&lock)==1 ){
InitializeCriticalSection(&cs);
isInit = 1;
}else{
Sleep(1);
}
}
EnterCriticalSection(&cs);
#endif
#ifdef SQLITE_MACOS_MULTITASKING
static volatile int notInit = 1;
if( notInit ){
if( notInit == 2 ) /* as close as you can get to thread safe init */
MPYield();
else{
notInit = 2;
MPCreateCriticalRegion(&criticalRegion);
notInit = 0;
}
}
MPEnterCriticalRegion(criticalRegion, kDurationForever);
#endif
assert( !inMutex );
inMutex = 1;
}
void sqliteOsLeaveMutex(){
assert( inMutex );
inMutex = 0;
#ifdef SQLITE_UNIX_THREADS
pthread_mutex_unlock(&mutex);
#endif
#ifdef SQLITE_W32_THREADS
LeaveCriticalSection(&cs);
#endif
#ifdef SQLITE_MACOS_MULTITASKING
MPExitCriticalRegion(criticalRegion);
#endif
}
/*
** Turn a relative pathname into a full pathname. Return a pointer
** to the full pathname stored in space obtained from sqliteMalloc().
** The calling function is responsible for freeing this space once it
** is no longer needed.
*/
char *sqliteOsFullPathname(const char *zRelative){
#if OS_UNIX
char *zFull = 0;
if( zRelative[0]=='/' ){
sqliteSetString(&zFull, zRelative, (char*)0);
}else{
char zBuf[5000];
sqliteSetString(&zFull, getcwd(zBuf, sizeof(zBuf)), "/", zRelative,
(char*)0);
}
return zFull;
#endif
#if OS_WIN
char *zNotUsed;
char *zFull;
int nByte;
( run in 0.495 second using v1.01-cache-2.11-cpan-e1769b4cff6 )