#include "os.h"
#if OS_UNIX /* This file is used on unix only */
+/* #define SQLITE_ENABLE_LOCKING_STYLE 0 */
+
/*
** These #defines should enable >2GB file support on Posix if the
** underlying operating system supports it. If the OS lacks
#include <time.h>
#include <sys/time.h>
#include <errno.h>
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+#include <sys/ioctl.h>
+#include <sys/param.h>
+#include <sys/mount.h>
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
/*
** If we are to be thread-safe, include the pthreads header and define
IoMethod const *pMethod; /* Always the first entry */
struct openCnt *pOpen; /* Info about all open fd's on this inode */
struct lockInfo *pLock; /* Info about locks on this inode */
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+ void *lockingContext; /* Locking style specific state */
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
int h; /* The file descriptor */
unsigned char locktype; /* The type of lock held on this fd */
unsigned char isOpen; /* True if needs to be closed */
static Hash openHash = {SQLITE_HASH_BINARY, 0, 0, 0,
sqlite3ThreadSafeMalloc, sqlite3ThreadSafeFree, 0, 0};
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+** The locking styles are associated with the different file locking
+** capabilities supported by different file systems.
+**
+** POSIX locking style fully supports shared and exclusive byte-range locks
+** ADP locking only supports exclusive byte-range locks
+** FLOCK only supports a single file-global exclusive lock
+** DOTLOCK isn't a true locking style, it refers to the use of a special
+** file named the same as the database file with a '.lock' extension, this
+** can be used on file systems that do not offer any reliable file locking
+** NO locking means that no locking will be attempted, this is only used for
+** read-only file systems currently
+** UNSUPPORTED means that no locking will be attempted, this is only used for
+** file systems that are known to be unsupported
+*/
+typedef enum {
+ posixLockingStyle = 0, /* standard posix-advisory locks */
+ afpLockingStyle, /* use afp locks */
+ flockLockingStyle, /* use flock() */
+ dotlockLockingStyle, /* use <file>.lock files */
+ noLockingStyle, /* useful for read-only file system */
+ unsupportedLockingStyle /* indicates unsupported file system */
+} sqlite3LockingStyle;
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
#ifdef SQLITE_UNIX_THREADS
/*
** This variable records whether or not threads can override each others
*/
static void releaseLockInfo(struct lockInfo *pLock){
assert( sqlite3OsInMutex(1) );
+ if (pLock == NULL)
+ return;
pLock->nRef--;
if( pLock->nRef==0 ){
sqlite3HashInsert(&lockHash, &pLock->key, sizeof(pLock->key), 0);
*/
static void releaseOpenCnt(struct openCnt *pOpen){
assert( sqlite3OsInMutex(1) );
+ if (pOpen == NULL)
+ return;
pOpen->nRef--;
if( pOpen->nRef==0 ){
sqlite3HashInsert(&openHash, &pOpen->key, sizeof(pOpen->key), 0);
}
}
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+** Tests a byte-range locking query to see if byte range locks are
+** supported, if not we fall back to dotlockLockingStyle.
+*/
+static sqlite3LockingStyle sqlite3TestLockingStyle(const char *filePath,
+ int fd) {
+ /* test byte-range lock using fcntl */
+ struct flock lockInfo;
+
+ lockInfo.l_len = 1;
+ lockInfo.l_start = 0;
+ lockInfo.l_whence = SEEK_SET;
+ lockInfo.l_type = F_RDLCK;
+
+ if (fcntl(fd, F_GETLK, (int) &lockInfo) != -1) {
+ return posixLockingStyle;
+ }
+
+ /* testing for flock can give false positives. So if if the above test
+ ** fails, then we fall back to using dot-lock style locking.
+ */
+ return dotlockLockingStyle;
+}
+
+/*
+** Examines the f_fstypename entry in the statfs structure as returned by
+** stat() for the file system hosting the database file, assigns the
+** appropriate locking style based on it's value. These values and
+** assignments are based on Darwin/OSX behavior and have not been tested on
+** other systems.
+*/
+static sqlite3LockingStyle sqlite3DetectLockingStyle(const char *filePath,
+ int fd) {
+
+#ifdef SQLITE_FIXED_LOCKING_STYLE
+ return (sqlite3LockingStyle)SQLITE_FIXED_LOCKING_STYLE;
+#else
+ struct statfs fsInfo;
+
+ if (statfs(filePath, &fsInfo) == -1)
+ return sqlite3TestLockingStyle(filePath, fd);
+
+ if (fsInfo.f_flags & MNT_RDONLY)
+ return noLockingStyle;
+
+ if( (!strcmp(fsInfo.f_fstypename, "hfs")) ||
+ (!strcmp(fsInfo.f_fstypename, "ufs")) )
+ return posixLockingStyle;
+
+ if(!strcmp(fsInfo.f_fstypename, "afpfs"))
+ return afpLockingStyle;
+
+ if(!strcmp(fsInfo.f_fstypename, "nfs"))
+ return sqlite3TestLockingStyle(filePath, fd);
+
+ if(!strcmp(fsInfo.f_fstypename, "smbfs"))
+ return flockLockingStyle;
+
+ if(!strcmp(fsInfo.f_fstypename, "msdos"))
+ return dotlockLockingStyle;
+
+ if(!strcmp(fsInfo.f_fstypename, "webdav"))
+ return unsupportedLockingStyle;
+
+ return sqlite3TestLockingStyle(filePath, fd);
+#endif // SQLITE_FIXED_LOCKING_STYLE
+}
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
/*
** Given a file descriptor, locate lockInfo and openCnt structures that
** describes that file descriptor. Create new ones if necessary. The
}
TRACE4("Transfer ownership of %d from %d to %d\n", pFile->h,pFile->tid,hSelf);
pFile->tid = hSelf;
- releaseLockInfo(pFile->pLock);
- rc = findLockInfo(pFile->h, &pFile->pLock, 0);
- TRACE5("LOCK %d is now %s(%s,%d)\n", pFile->h,
- locktypeName(pFile->locktype),
- locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
- return rc;
+ if (pFile->pLock != NULL) {
+ releaseLockInfo(pFile->pLock);
+ rc = findLockInfo(pFile->h, &pFile->pLock, 0);
+ TRACE5("LOCK %d is now %s(%s,%d)\n", pFile->h,
+ locktypeName(pFile->locktype),
+ locktypeName(pFile->pLock->locktype), pFile->pLock->cnt);
+ return rc;
+ } else {
+ return SQLITE_OK;
+ }
}
#else
/* On single-threaded builds, ownership transfer is a no-op */
}
/* Forward declaration */
-static int allocateUnixFile(unixFile *pInit, OsFile **pId);
+static int allocateUnixFile(
+ int h, /* File descriptor of the open file */
+ OsFile **pId, /* Write the real file descriptor here */
+ const char *zFilename, /* Name of the file being opened */
+ int delFlag /* If true, make sure the file deletes on close */
+);
/*
** Attempt to open a file for both reading and writing. If that
OsFile **pId,
int *pReadonly
){
- int rc;
- unixFile f;
-
+ int h;
+
CRASH_TEST_OVERRIDE(sqlite3CrashOpenReadWrite, zFilename, pId, pReadonly);
assert( 0==*pId );
- f.h = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY,
- SQLITE_DEFAULT_FILE_PERMISSIONS);
- if( f.h<0 ){
+ h = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY,
+ SQLITE_DEFAULT_FILE_PERMISSIONS);
+ if( h<0 ){
#ifdef EISDIR
if( errno==EISDIR ){
return SQLITE_CANTOPEN;
}
#endif
- f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
- if( f.h<0 ){
+ h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
+ if( h<0 ){
return SQLITE_CANTOPEN;
}
*pReadonly = 1;
}else{
*pReadonly = 0;
}
- sqlite3OsEnterMutex();
- rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
- sqlite3OsLeaveMutex();
- if( rc ){
- close(f.h);
- return SQLITE_NOMEM;
- }
- TRACE3("OPEN %-3d %s\n", f.h, zFilename);
- return allocateUnixFile(&f, pId);
+ return allocateUnixFile(h, pId, zFilename, 0);
}
** On failure, return SQLITE_CANTOPEN.
*/
int sqlite3UnixOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
- int rc;
- unixFile f;
+ int h;
CRASH_TEST_OVERRIDE(sqlite3CrashOpenExclusive, zFilename, pId, delFlag);
assert( 0==*pId );
- f.h = open(zFilename,
+ h = open(zFilename,
O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY,
SQLITE_DEFAULT_FILE_PERMISSIONS);
- if( f.h<0 ){
+ if( h<0 ){
return SQLITE_CANTOPEN;
}
- sqlite3OsEnterMutex();
- rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
- sqlite3OsLeaveMutex();
- if( rc ){
- close(f.h);
- unlink(zFilename);
- return SQLITE_NOMEM;
- }
- if( delFlag ){
- unlink(zFilename);
- }
- TRACE3("OPEN-EX %-3d %s\n", f.h, zFilename);
- return allocateUnixFile(&f, pId);
+ return allocateUnixFile(h, pId, zFilename, delFlag);
}
/*
** On failure, return SQLITE_CANTOPEN.
*/
int sqlite3UnixOpenReadOnly(const char *zFilename, OsFile **pId){
- int rc;
- unixFile f;
-
+ int h;
+
CRASH_TEST_OVERRIDE(sqlite3CrashOpenReadOnly, zFilename, pId, 0);
assert( 0==*pId );
- f.h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
- if( f.h<0 ){
+ h = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY);
+ if( h<0 ){
return SQLITE_CANTOPEN;
}
- sqlite3OsEnterMutex();
- rc = findLockInfo(f.h, &f.pLock, &f.pOpen);
- sqlite3OsLeaveMutex();
- if( rc ){
- close(f.h);
- return SQLITE_NOMEM;
- }
- TRACE3("OPEN-RO %-3d %s\n", f.h, zFilename);
- return allocateUnixFile(&f, pId);
+ return allocateUnixFile(h, pId, zFilename, 0);
}
/*
** This routine is only meaningful for Unix. It is a no-op under
** windows since windows does not support hard links.
**
+** If FULL_FSYNC is enabled, this function is not longer useful,
+** a FULL_FSYNC sync applies to all pending disk operations.
+**
** On success, a handle for a previously open file at *id is
** updated with the new directory file descriptor and SQLITE_OK is
** returned.
return SQLITE_OK;
}
+
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+#pragma mark AFP Support
+
+/*
+ ** The afpLockingContext structure contains all afp lock specific state
+ */
+typedef struct afpLockingContext afpLockingContext;
+struct afpLockingContext {
+ unsigned long long sharedLockByte;
+ char *filePath;
+};
+
+struct ByteRangeLockPB2
+{
+ unsigned long long offset; /* offset to first byte to lock */
+ unsigned long long length; /* nbr of bytes to lock */
+ unsigned long long retRangeStart; /* nbr of 1st byte locked if successful */
+ unsigned char unLockFlag; /* 1 = unlock, 0 = lock */
+ unsigned char startEndFlag; /* 1=rel to end of fork, 0=rel to start */
+ int fd; /* file desc to assoc this lock with */
+};
+
+#define afpfsByteRangeLock2FSCTL _IOWR('z', 23, struct ByteRangeLockPB2)
+
+/* return 0 on success, 1 on failure. To match the behavior of the
+ normal posix file locking (used in unixLock for example), we should
+ provide 'richer' return codes - specifically to differentiate between
+ 'file busy' and 'file system error' results */
+static int _AFPFSSetLock(const char *path, int fd, unsigned long long offset,
+ unsigned long long length, int setLockFlag)
+{
+ struct ByteRangeLockPB2 pb;
+ int err;
+
+ pb.unLockFlag = setLockFlag ? 0 : 1;
+ pb.startEndFlag = 0;
+ pb.offset = offset;
+ pb.length = length;
+ pb.fd = fd;
+ TRACE5("AFPLOCK setting lock %s for %d in range %llx:%llx\n",
+ (setLockFlag?"ON":"OFF"), fd, offset, length);
+ err = fsctl(path, afpfsByteRangeLock2FSCTL, &pb, 0);
+ if ( err==-1 ) {
+ TRACE4("AFPLOCK failed to fsctl() '%s' %d %s\n", path, errno,
+ strerror(errno));
+ return 1; // error
+ } else {
+ return 0;
+ }
+}
+
+/*
+ ** This routine checks if there is a RESERVED lock held on the specified
+ ** file by this or any other process. If such a lock is held, return
+ ** non-zero. If the file is unlocked or holds only SHARED locks, then
+ ** return zero.
+ */
+static int afpUnixCheckReservedLock(OsFile *id){
+ int r = 0;
+ unixFile *pFile = (unixFile*)id;
+
+ assert( pFile );
+ afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+
+ /* Check if a thread in this process holds such a lock */
+ if( pFile->locktype>SHARED_LOCK ){
+ r = 1;
+ }
+
+ /* Otherwise see if some other process holds it.
+ */
+ if ( !r ) {
+ // lock the byte
+ int failed = _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1,1);
+ if (failed) {
+ /* if we failed to get the lock then someone else must have it */
+ r = 1;
+ } else {
+ /* if we succeeded in taking the reserved lock, unlock it to restore
+ ** the original state */
+ _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0);
+ }
+ }
+ TRACE3("TEST WR-LOCK %d %d\n", pFile->h, r);
+
+ return r;
+}
+
+/* AFP-style locking following the behavior of unixLock, see the unixLock
+** function comments for details of lock management. */
+static int afpUnixLock(OsFile *id, int locktype)
+{
+ int rc = SQLITE_OK;
+ unixFile *pFile = (unixFile*)id;
+ afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+ int gotPendingLock = 0;
+
+ assert( pFile );
+ TRACE5("LOCK %d %s was %s pid=%d\n", pFile->h,
+ locktypeName(locktype), locktypeName(pFile->locktype), getpid());
+ /* If there is already a lock of this type or more restrictive on the
+ ** OsFile, do nothing. Don't use the afp_end_lock: exit path, as
+ ** sqlite3OsEnterMutex() hasn't been called yet.
+ */
+ if( pFile->locktype>=locktype ){
+ TRACE3("LOCK %d %s ok (already held)\n", pFile->h,
+ locktypeName(locktype));
+ return SQLITE_OK;
+ }
+
+ /* Make sure the locking sequence is correct
+ */
+ assert( pFile->locktype!=NO_LOCK || locktype==SHARED_LOCK );
+ assert( locktype!=PENDING_LOCK );
+ assert( locktype!=RESERVED_LOCK || pFile->locktype==SHARED_LOCK );
+
+ /* This mutex is needed because pFile->pLock is shared across threads
+ */
+ sqlite3OsEnterMutex();
+
+ /* Make sure the current thread owns the pFile.
+ */
+ rc = transferOwnership(pFile);
+ if( rc!=SQLITE_OK ){
+ sqlite3OsLeaveMutex();
+ return rc;
+ }
+
+ /* A PENDING lock is needed before acquiring a SHARED lock and before
+ ** acquiring an EXCLUSIVE lock. For the SHARED lock, the PENDING will
+ ** be released.
+ */
+ if( locktype==SHARED_LOCK
+ || (locktype==EXCLUSIVE_LOCK && pFile->locktype<PENDING_LOCK)
+ ){
+ int failed = _AFPFSSetLock(context->filePath, pFile->h,
+ PENDING_BYTE, 1, 1);
+ if (failed) {
+ rc = SQLITE_BUSY;
+ goto afp_end_lock;
+ }
+ }
+
+ /* If control gets to this point, then actually go ahead and make
+ ** operating system calls for the specified lock.
+ */
+ if( locktype==SHARED_LOCK ){
+ int lk, failed;
+ int tries = 0;
+
+ /* Now get the read-lock */
+ /* note that the quality of the randomness doesn't matter that much */
+ lk = random();
+ context->sharedLockByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
+ failed = _AFPFSSetLock(context->filePath, pFile->h,
+ SHARED_FIRST+context->sharedLockByte, 1, 1);
+
+ /* Drop the temporary PENDING lock */
+ if (_AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 0)) {
+ rc = SQLITE_IOERR_UNLOCK; /* This should never happen */
+ goto afp_end_lock;
+ }
+
+ if( failed ){
+ rc = SQLITE_BUSY;
+ } else {
+ pFile->locktype = SHARED_LOCK;
+ }
+ }else{
+ /* The request was for a RESERVED or EXCLUSIVE lock. It is
+ ** assumed that there is a SHARED or greater lock on the file
+ ** already.
+ */
+ int failed = 0;
+ assert( 0!=pFile->locktype );
+ if (locktype >= RESERVED_LOCK && pFile->locktype < RESERVED_LOCK) {
+ /* Acquire a RESERVED lock */
+ failed = _AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1,1);
+ }
+ if (!failed && locktype == EXCLUSIVE_LOCK) {
+ /* Acquire an EXCLUSIVE lock */
+
+ /* Remove the shared lock before trying the range. we'll need to
+ ** reestablish the shared lock if we can't get the afpUnixUnlock
+ */
+ if (!_AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST +
+ context->sharedLockByte, 1, 0)) {
+ /* now attemmpt to get the exclusive lock range */
+ failed = _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST,
+ SHARED_SIZE, 1);
+ if (failed && _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST +
+ context->sharedLockByte, 1, 1)) {
+ rc = SQLITE_IOERR_RDLOCK; /* this should never happen */
+ }
+ } else {
+ /* */
+ rc = SQLITE_IOERR_UNLOCK; /* this should never happen */
+ }
+ }
+ if( failed && rc == SQLITE_OK){
+ rc = SQLITE_BUSY;
+ }
+ }
+
+ if( rc==SQLITE_OK ){
+ pFile->locktype = locktype;
+ }else if( locktype==EXCLUSIVE_LOCK ){
+ pFile->locktype = PENDING_LOCK;
+ }
+
+afp_end_lock:
+ sqlite3OsLeaveMutex();
+ TRACE4("LOCK %d %s %s\n", pFile->h, locktypeName(locktype),
+ rc==SQLITE_OK ? "ok" : "failed");
+ 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 afpUnixUnlock(OsFile *id, int locktype) {
+ struct flock lock;
+ int rc = SQLITE_OK;
+ unixFile *pFile = (unixFile*)id;
+ afpLockingContext *context = (afpLockingContext *) pFile->lockingContext;
+
+ assert( pFile );
+ TRACE5("UNLOCK %d %d was %d pid=%d\n", pFile->h, locktype,
+ pFile->locktype, getpid());
+
+ assert( locktype<=SHARED_LOCK );
+ if( pFile->locktype<=locktype ){
+ return SQLITE_OK;
+ }
+ if( CHECK_THREADID(pFile) ){
+ return SQLITE_MISUSE;
+ }
+ sqlite3OsEnterMutex();
+ if( pFile->locktype>SHARED_LOCK ){
+ if( locktype==SHARED_LOCK ){
+ int failed = 0;
+
+ /* unlock the exclusive range - then re-establish the shared lock */
+ if (pFile->locktype==EXCLUSIVE_LOCK) {
+ failed = _AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST,
+ SHARED_SIZE, 0);
+ if (!failed) {
+ /* successfully removed the exclusive lock */
+ if (_AFPFSSetLock(context->filePath, pFile->h, SHARED_FIRST+
+ context->sharedLockByte, 1, 1)) {
+ /* failed to re-establish our shared lock */
+ rc = SQLITE_IOERR_RDLOCK; /* This should never happen */
+ }
+ } else {
+ /* This should never happen - failed to unlock the exclusive range */
+ rc = SQLITE_IOERR_UNLOCK;
+ }
+ }
+ }
+ if (rc == SQLITE_OK && pFile->locktype>=PENDING_LOCK) {
+ if (_AFPFSSetLock(context->filePath, pFile->h, PENDING_BYTE, 1, 0)){
+ /* failed to release the pending lock */
+ rc = SQLITE_IOERR_UNLOCK; /* This should never happen */
+ }
+ }
+ if (rc == SQLITE_OK && pFile->locktype>=RESERVED_LOCK) {
+ if (_AFPFSSetLock(context->filePath, pFile->h, RESERVED_BYTE, 1, 0)) {
+ /* failed to release the reserved lock */
+ rc = SQLITE_IOERR_UNLOCK; /* This should never happen */
+ }
+ }
+ }
+ if( locktype==NO_LOCK ){
+ int failed = _AFPFSSetLock(context->filePath, pFile->h,
+ SHARED_FIRST + context->sharedLockByte, 1, 0);
+ if (failed) {
+ rc = SQLITE_IOERR_UNLOCK; /* This should never happen */
+ }
+ }
+ if (rc == SQLITE_OK)
+ pFile->locktype = locktype;
+ sqlite3OsLeaveMutex();
+ return rc;
+}
+
+/*
+ ** Close a file & cleanup AFP specific locking context
+ */
+static int afpUnixClose(OsFile **pId) {
+ unixFile *id = (unixFile*)*pId;
+
+ if( !id ) return SQLITE_OK;
+ afpUnixUnlock(*pId, NO_LOCK);
+ /* free the AFP locking structure */
+ if (id->lockingContext != NULL) {
+ if (((afpLockingContext *)id->lockingContext)->filePath != NULL)
+ sqlite3ThreadSafeFree(((afpLockingContext*)id->lockingContext)->filePath);
+ sqlite3ThreadSafeFree(id->lockingContext);
+ }
+
+ if( id->dirfd>=0 ) close(id->dirfd);
+ id->dirfd = -1;
+ close(id->h);
+ id->isOpen = 0;
+ TRACE2("CLOSE %-3d\n", id->h);
+ OpenCounter(-1);
+ sqlite3ThreadSafeFree(id);
+ *pId = 0;
+ return SQLITE_OK;
+}
+
+
+#pragma mark flock() style locking
+
+/*
+ ** The flockLockingContext is not used
+ */
+typedef void flockLockingContext;
+
+static int flockUnixCheckReservedLock(OsFile *id) {
+ unixFile *pFile = (unixFile*)id;
+
+ if (pFile->locktype == RESERVED_LOCK) {
+ return 1; // already have a reserved lock
+ } else {
+ // attempt to get the lock
+ int rc = flock(pFile->h, LOCK_EX | LOCK_NB);
+ if (!rc) {
+ // got the lock, unlock it
+ flock(pFile->h, LOCK_UN);
+ return 0; // no one has it reserved
+ }
+ return 1; // someone else might have it reserved
+ }
+}
+
+static int flockUnixLock(OsFile *id, int locktype) {
+ unixFile *pFile = (unixFile*)id;
+
+ // if we already have a lock, it is exclusive.
+ // Just adjust level and punt on outta here.
+ if (pFile->locktype > NO_LOCK) {
+ pFile->locktype = locktype;
+ return SQLITE_OK;
+ }
+
+ // grab an exclusive lock
+ int rc = flock(pFile->h, LOCK_EX | LOCK_NB);
+ if (rc) {
+ // didn't get, must be busy
+ return SQLITE_BUSY;
+ } else {
+ // got it, set the type and return ok
+ pFile->locktype = locktype;
+ return SQLITE_OK;
+ }
+}
+
+static int flockUnixUnlock(OsFile *id, int locktype) {
+ unixFile *pFile = (unixFile*)id;
+
+ assert( locktype<=SHARED_LOCK );
+
+ // no-op if possible
+ if( pFile->locktype==locktype ){
+ return SQLITE_OK;
+ }
+
+ // shared can just be set because we always have an exclusive
+ if (locktype==SHARED_LOCK) {
+ pFile->locktype = locktype;
+ return SQLITE_OK;
+ }
+
+ // no, really, unlock.
+ int rc = flock(pFile->h, LOCK_UN);
+ if (rc)
+ return SQLITE_IOERR_UNLOCK;
+ else {
+ pFile->locktype = NO_LOCK;
+ return SQLITE_OK;
+ }
+}
+
+/*
+ ** Close a file.
+ */
+static int flockUnixClose(OsFile **pId) {
+ unixFile *id = (unixFile*)*pId;
+
+ if( !id ) return SQLITE_OK;
+ flockUnixUnlock(*pId, NO_LOCK);
+
+ if( id->dirfd>=0 ) close(id->dirfd);
+ id->dirfd = -1;
+ sqlite3OsEnterMutex();
+
+ close(id->h);
+ sqlite3OsLeaveMutex();
+ id->isOpen = 0;
+ TRACE2("CLOSE %-3d\n", id->h);
+ OpenCounter(-1);
+ sqlite3ThreadSafeFree(id);
+ *pId = 0;
+ return SQLITE_OK;
+}
+
+#pragma mark Old-School .lock file based locking
+
+/*
+ ** The dotlockLockingContext structure contains all dotlock (.lock) lock
+ ** specific state
+ */
+typedef struct dotlockLockingContext dotlockLockingContext;
+struct dotlockLockingContext {
+ char *lockPath;
+};
+
+
+static int dotlockUnixCheckReservedLock(OsFile *id) {
+ unixFile *pFile = (unixFile*)id;
+ dotlockLockingContext *context =
+ (dotlockLockingContext *) pFile->lockingContext;
+
+ if (pFile->locktype == RESERVED_LOCK) {
+ return 1; // already have a reserved lock
+ } else {
+ struct stat statBuf;
+ if (lstat(context->lockPath,&statBuf) == 0)
+ // file exists, someone else has the lock
+ return 1;
+ else
+ // file does not exist, we could have it if we want it
+ return 0;
+ }
+}
+
+static int dotlockUnixLock(OsFile *id, int locktype) {
+ unixFile *pFile = (unixFile*)id;
+ dotlockLockingContext *context =
+ (dotlockLockingContext *) pFile->lockingContext;
+
+ // if we already have a lock, it is exclusive.
+ // Just adjust level and punt on outta here.
+ if (pFile->locktype > NO_LOCK) {
+ pFile->locktype = locktype;
+
+ /* Always update the timestamp on the old file */
+ utimes(context->lockPath,NULL);
+ return SQLITE_OK;
+ }
+
+ // check to see if lock file already exists
+ struct stat statBuf;
+ if (lstat(context->lockPath,&statBuf) == 0){
+ return SQLITE_BUSY; // it does, busy
+ }
+
+ // grab an exclusive lock
+ int fd = open(context->lockPath,O_RDONLY|O_CREAT|O_EXCL,0600);
+ if (fd < 0) {
+ // failed to open/create the file, someone else may have stolen the lock
+ return SQLITE_BUSY;
+ }
+ close(fd);
+
+ // got it, set the type and return ok
+ pFile->locktype = locktype;
+ return SQLITE_OK;
+}
+
+static int dotlockUnixUnlock(OsFile *id, int locktype) {
+ unixFile *pFile = (unixFile*)id;
+ dotlockLockingContext *context =
+ (dotlockLockingContext *) pFile->lockingContext;
+
+ assert( locktype<=SHARED_LOCK );
+
+ // no-op if possible
+ if( pFile->locktype==locktype ){
+ return SQLITE_OK;
+ }
+
+ // shared can just be set because we always have an exclusive
+ if (locktype==SHARED_LOCK) {
+ pFile->locktype = locktype;
+ return SQLITE_OK;
+ }
+
+ // no, really, unlock.
+ unlink(context->lockPath);
+ pFile->locktype = NO_LOCK;
+ return SQLITE_OK;
+}
+
+/*
+ ** Close a file.
+ */
+static int dotlockUnixClose(OsFile **pId) {
+ unixFile *id = (unixFile*)*pId;
+
+ if( !id ) return SQLITE_OK;
+ dotlockUnixUnlock(*pId, NO_LOCK);
+ /* free the dotlock locking structure */
+ if (id->lockingContext != NULL) {
+ if (((dotlockLockingContext *)id->lockingContext)->lockPath != NULL)
+ sqlite3ThreadSafeFree( ( (dotlockLockingContext *)
+ id->lockingContext)->lockPath);
+ sqlite3ThreadSafeFree(id->lockingContext);
+ }
+
+ if( id->dirfd>=0 ) close(id->dirfd);
+ id->dirfd = -1;
+ sqlite3OsEnterMutex();
+
+ close(id->h);
+
+ sqlite3OsLeaveMutex();
+ id->isOpen = 0;
+ TRACE2("CLOSE %-3d\n", id->h);
+ OpenCounter(-1);
+ sqlite3ThreadSafeFree(id);
+ *pId = 0;
+ return SQLITE_OK;
+}
+
+
+#pragma mark No locking
+
+/*
+ ** The nolockLockingContext is void
+ */
+typedef void nolockLockingContext;
+
+static int nolockUnixCheckReservedLock(OsFile *id) {
+ return 0;
+}
+
+static int nolockUnixLock(OsFile *id, int locktype) {
+ return SQLITE_OK;
+}
+
+static int nolockUnixUnlock(OsFile *id, int locktype) {
+ return SQLITE_OK;
+}
+
+/*
+ ** Close a file.
+ */
+static int nolockUnixClose(OsFile **pId) {
+ unixFile *id = (unixFile*)*pId;
+
+ if( !id ) return SQLITE_OK;
+ if( id->dirfd>=0 ) close(id->dirfd);
+ id->dirfd = -1;
+ sqlite3OsEnterMutex();
+
+ close(id->h);
+
+ sqlite3OsLeaveMutex();
+ id->isOpen = 0;
+ TRACE2("CLOSE %-3d\n", id->h);
+ OpenCounter(-1);
+ sqlite3ThreadSafeFree(id);
+ *pId = 0;
+ return SQLITE_OK;
+}
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
/*
** Turn a relative pathname into a full pathname. Return a pointer
** to the full pathname stored in space obtained from sqliteMalloc().
unixCheckReservedLock,
};
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+ ** This vector defines all the methods that can operate on an OsFile
+ ** for unix with AFP style file locking.
+ */
+static const IoMethod sqlite3AFPLockingUnixIoMethod = {
+ afpUnixClose,
+ unixOpenDirectory,
+ unixRead,
+ unixWrite,
+ unixSeek,
+ unixTruncate,
+ unixSync,
+ unixSetFullSync,
+ unixFileHandle,
+ unixFileSize,
+ afpUnixLock,
+ afpUnixUnlock,
+ unixLockState,
+ afpUnixCheckReservedLock,
+};
+
+/*
+ ** This vector defines all the methods that can operate on an OsFile
+ ** for unix with flock() style file locking.
+ */
+static const IoMethod sqlite3FlockLockingUnixIoMethod = {
+ flockUnixClose,
+ unixOpenDirectory,
+ unixRead,
+ unixWrite,
+ unixSeek,
+ unixTruncate,
+ unixSync,
+ unixSetFullSync,
+ unixFileHandle,
+ unixFileSize,
+ flockUnixLock,
+ flockUnixUnlock,
+ unixLockState,
+ flockUnixCheckReservedLock,
+};
+
+/*
+ ** This vector defines all the methods that can operate on an OsFile
+ ** for unix with dotlock style file locking.
+ */
+static const IoMethod sqlite3DotlockLockingUnixIoMethod = {
+ dotlockUnixClose,
+ unixOpenDirectory,
+ unixRead,
+ unixWrite,
+ unixSeek,
+ unixTruncate,
+ unixSync,
+ unixSetFullSync,
+ unixFileHandle,
+ unixFileSize,
+ dotlockUnixLock,
+ dotlockUnixUnlock,
+ unixLockState,
+ dotlockUnixCheckReservedLock,
+};
+
+/*
+ ** This vector defines all the methods that can operate on an OsFile
+ ** for unix with dotlock style file locking.
+ */
+static const IoMethod sqlite3NolockLockingUnixIoMethod = {
+ nolockUnixClose,
+ unixOpenDirectory,
+ unixRead,
+ unixWrite,
+ unixSeek,
+ unixTruncate,
+ unixSync,
+ unixSetFullSync,
+ unixFileHandle,
+ unixFileSize,
+ nolockUnixLock,
+ nolockUnixUnlock,
+ unixLockState,
+ nolockUnixCheckReservedLock,
+};
+
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
+
/*
-** Allocate memory for a unixFile. Initialize the new unixFile
-** to the value given in pInit and return a pointer to the new
-** OsFile. If we run out of memory, close the file and return NULL.
+** Allocate memory for a new unixFile and initialize that unixFile.
+** Write a pointer to the new unixFile into *pId.
+** If we run out of memory, close the file and return an error.
*/
-static int allocateUnixFile(unixFile *pInit, OsFile **pId){
+#ifdef SQLITE_ENABLE_LOCKING_STYLE
+/*
+ ** When locking extensions are enabled, the filepath and locking style
+ ** are needed to determine the unixFile pMethod to use for locking operations.
+ ** The locking-style specific lockingContext data structure is created
+ ** and assigned here also.
+ */
+static int allocateUnixFile(
+ int h, /* Open file descriptor of file being opened */
+ OsFile **pId, /* Write completed initialization here */
+ const char *zFilename, /* Name of the file being opened */
+ int delFlag /* Delete-on-or-before-close flag */
+){
+ sqlite3LockingStyle lockStyle;
unixFile *pNew;
- pInit->dirfd = -1;
- pInit->fullSync = 0;
- pInit->locktype = 0;
- pInit->offset = 0;
- SET_THREADID(pInit);
+ unixFile f;
+ int rc;
+
+ lockingStyle = sqlite3DetectLockingStyle(zFilename, f.h);
+ if ( lockingStyle == posixLockingStyle ) {
+ sqlite3OsEnterMutex();
+ rc = findLockInfo(h, &f.pLock, &f.pOpen);
+ sqlite3OsLeaveMutex();
+ if( rc ){
+ close(h);
+ unlink(zFilename);
+ return SQLITE_NOMEM;
+ }
+ } else {
+ // pLock and pOpen are only used for posix advisory locking
+ f.pLock = NULL;
+ f.pOpen = NULL;
+ }
+ if( delFlag ){
+ unlink(zFilename);
+ }
+ f.dirfd = -1;
+ f.fullSync = 0;
+ f.locktype = 0;
+ f.offset = 0;
+ f.h = h;
+ SET_THREADID(&f);
pNew = sqlite3ThreadSafeMalloc( sizeof(unixFile) );
if( pNew==0 ){
- close(pInit->h);
+ close(h);
sqlite3OsEnterMutex();
- releaseLockInfo(pInit->pLock);
- releaseOpenCnt(pInit->pOpen);
+ releaseLockInfo(f.pLock);
+ releaseOpenCnt(f.pOpen);
sqlite3OsLeaveMutex();
*pId = 0;
return SQLITE_NOMEM;
}else{
- *pNew = *pInit;
- pNew->pMethod = &sqlite3UnixIoMethod;
+ *pNew = f;
+ switch(lockStyle) {
+ case afpLockingStyle:
+ /* afp locking uses the file path so it needs to be included in
+ ** the afpLockingContext */
+ pNew->pMethod = &sqlite3AFPLockingUnixIoMethod;
+ pNew->lockingContext =
+ sqlite3ThreadSafeMalloc(sizeof(afpLockingContext));
+ ((afpLockingContext *)pNew->lockingContext)->filePath =
+ sqlite3ThreadSafeMalloc(strlen(zFilename) + 1);
+ strcpy(((afpLockingContext *)pNew->lockingContext)->filePath,
+ zFilename);
+ srandomdev();
+ break;
+ case flockLockingStyle:
+ /* flock locking doesn't need additional lockingContext information */
+ pNew->pMethod = &sqlite3FlockLockingUnixIoMethod;
+ break;
+ case dotlockLockingStyle:
+ /* dotlock locking uses the file path so it needs to be included in
+ ** the dotlockLockingContext */
+ pNew->pMethod = &sqlite3DotlockLockingUnixIoMethod;
+ pNew->lockingContext = sqlite3ThreadSafeMalloc(
+ sizeof(dotlockLockingContext));
+ ((dotlockLockingContext *)pNew->lockingContext)->lockPath =
+ sqlite3ThreadSafeMalloc(strlen(zFilename) + strlen(".lock") + 1);
+ sprintf(((dotlockLockingContext *)pNew->lockingContext)->lockPath,
+ "%s.lock", zFilename);
+ break;
+ case posixLockingStyle:
+ /* posix locking doesn't need additional lockingContext information */
+ pNew->pMethod = &sqlite3UnixIoMethod;
+ break;
+ case noLockingStyle:
+ case unsupportedLockingStyle:
+ default:
+ pNew->pMethod = &sqlite3NolockLockingUnixIoMethod;
+ }
*pId = (OsFile*)pNew;
OpenCounter(+1);
return SQLITE_OK;
}
}
+#else /* SQLITE_ENABLE_LOCKING_STYLE */
+static int allocateUnixFile(
+ int h, /* Open file descriptor on file being opened */
+ OsFile **pId, /* Write the resul unixFile structure here */
+ const char *zFilename, /* Name of the file being opened */
+ int delFlag /* If true, delete the file on or before closing */
+){
+ unixFile *pNew;
+ unixFile f;
+ int rc;
+ sqlite3OsEnterMutex();
+ rc = findLockInfo(h, &f.pLock, &f.pOpen);
+ sqlite3OsLeaveMutex();
+ if( delFlag ){
+ unlink(zFilename);
+ }
+ if( rc ){
+ close(h);
+ return SQLITE_NOMEM;
+ }
+ TRACE3("OPEN %-3d %s\n", h, zFilename);
+ f.dirfd = -1;
+ f.fullSync = 0;
+ f.locktype = 0;
+ f.offset = 0;
+ f.h = h;
+ SET_THREADID(&f);
+ pNew = sqlite3ThreadSafeMalloc( sizeof(unixFile) );
+ if( pNew==0 ){
+ close(h);
+ sqlite3OsEnterMutex();
+ releaseLockInfo(f.pLock);
+ releaseOpenCnt(f.pOpen);
+ sqlite3OsLeaveMutex();
+ *pId = 0;
+ return SQLITE_NOMEM;
+ }else{
+ *pNew = f;
+ pNew->pMethod = &sqlite3UnixIoMethod;
+ *pId = (OsFile*)pNew;
+ OpenCounter(+1);
+ return SQLITE_OK;
+ }
+}
+#endif /* SQLITE_ENABLE_LOCKING_STYLE */
#endif /* SQLITE_OMIT_DISKIO */
/***************************************************************************
projects / thirdparty / sqlite.git / commitdiff
