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Overview
| Comment: | Use mkdir() and rmdir() rather than open() and unlink() to create the lock files with the unix-dotlock VFS. The change is backwards compatible and, we are told, works better on some network filesystems. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
e2f08426d7a84a2ac6148f485b7af377 |
| User & Date: | drh 2011-11-04 02:24:02 |
Context
|
2011-11-04
| ||
| 10:37 | Add a missing va_end() macro to fts3.c. check-in: e6f82574 user: dan tags: trunk | |
| 02:24 | Use mkdir() and rmdir() rather than open() and unlink() to create the lock files with the unix-dotlock VFS. The change is backwards compatible and, we are told, works better on some network filesystems. check-in: e2f08426 user: drh tags: trunk | |
| 00:35 | Enhance the shell so that the ".schema" command works with case insensitive LIKE patterns even with PRAGMA cache_sensitive_like=ON. check-in: b06bf3b3 user: drh tags: trunk | |
Changes
Changes to src/os_unix.c.
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{ "unlink", (sqlite3_syscall_ptr)unlink, 0 },
#define osUnlink ((int(*)(const char*))aSyscall[16].pCurrent)
{ "openDirectory", (sqlite3_syscall_ptr)openDirectory, 0 },
#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)
}; /* End of the overrideable system calls */
/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "unix" VFSes. Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.
................................................................................
/******************* End of the no-op lock implementation *********************
******************************************************************************/
/******************************************************************************
************************* Begin dot-file Locking ******************************
**
** The dotfile locking implementation uses the existance of separate lock
** files in order to control access to the database. This works on just
** about every filesystem imaginable. But there are serious downsides:
**
** (1) There is zero concurrency. A single reader blocks all other
** connections from reading or writing the database.
**
** (2) An application crash or power loss can leave stale lock files
** sitting around that need to be cleared manually.
**
** Nevertheless, a dotlock is an appropriate locking mode for use if no
** other locking strategy is available.
**
** Dotfile locking works by creating a file in the same directory as the
** database and with the same name but with a ".lock" extension added.
** The existance of a lock file implies an EXCLUSIVE lock. All other lock
** types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
*/
/*
** The file suffix added to the data base filename in order to create the
** lock file.
*/
#define DOTLOCK_SUFFIX ".lock"
/*
** 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, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero. The return value
................................................................................
** routine to lower a locking level.
**
** With dotfile locking, we really only support state (4): EXCLUSIVE.
** But we track the other locking levels internally.
*/
static int dotlockLock(sqlite3_file *id, int eFileLock) {
unixFile *pFile = (unixFile*)id;
int fd;
char *zLockFile = (char *)pFile->lockingContext;
int rc = SQLITE_OK;
/* If we have any lock, then the lock file already exists. All we have
** to do is adjust our internal record of the lock level.
*/
................................................................................
#else
utimes(zLockFile, NULL);
#endif
return SQLITE_OK;
}
/* grab an exclusive lock */
fd = robust_open(zLockFile,O_RDONLY|O_CREAT|O_EXCL,0600);
if( fd<0 ){
/* failed to open/create the file, someone else may have stolen the lock */
int tErrno = errno;
if( EEXIST == tErrno ){
rc = SQLITE_BUSY;
} else {
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
}
return rc;
}
robust_close(pFile, fd, __LINE__);
/* got it, set the type and return ok */
pFile->eFileLock = eFileLock;
return rc;
}
/*
................................................................................
** the requested locking level, this routine is a no-op.
**
** When the locking level reaches NO_LOCK, delete the lock file.
*/
static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
unixFile *pFile = (unixFile*)id;
char *zLockFile = (char *)pFile->lockingContext;
assert( pFile );
OSTRACE(("UNLOCK %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
pFile->eFileLock, getpid()));
assert( eFileLock<=SHARED_LOCK );
/* no-op if possible */
................................................................................
if( eFileLock==SHARED_LOCK ){
pFile->eFileLock = SHARED_LOCK;
return SQLITE_OK;
}
/* To fully unlock the database, delete the lock file */
assert( eFileLock==NO_LOCK );
if( osUnlink(zLockFile) ){
int rc = 0;
int tErrno = errno;
if( ENOENT != tErrno ){
rc = SQLITE_IOERR_UNLOCK;
}
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
................................................................................
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 ) {
OSTRACE(("CREATELOCKPATH FAILED creating %s, "
"'%s' proxy lock path=%s pid=%d\n",
buf, strerror(err), lockPath, getpid()));
return err;
}
................................................................................
UNIXVFS("unix-proxy", proxyIoFinder ),
#endif
};
unsigned int i; /* Loop counter */
/* Double-check that the aSyscall[] array has been constructed
** correctly. See ticket [bb3a86e890c8e96ab] */
assert( ArraySize(aSyscall)==18 );
/* Register all VFSes defined in the aVfs[] array */
for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
sqlite3_vfs_register(&aVfs[i], i==0);
}
return SQLITE_OK;
}
|
> > > > > > | | | | | | | < | | | < > > | > | | |
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{ "unlink", (sqlite3_syscall_ptr)unlink, 0 },
#define osUnlink ((int(*)(const char*))aSyscall[16].pCurrent)
{ "openDirectory", (sqlite3_syscall_ptr)openDirectory, 0 },
#define osOpenDirectory ((int(*)(const char*,int*))aSyscall[17].pCurrent)
{ "mkdir", (sqlite3_syscall_ptr)mkdir, 0 },
#define osMkdir ((int(*)(const char*,mode_t))aSyscall[18].pCurrent)
{ "rmdir", (sqlite3_syscall_ptr)rmdir, 0 },
#define osRmdir ((int(*)(const char*))aSyscall[19].pCurrent)
}; /* End of the overrideable system calls */
/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "unix" VFSes. Return SQLITE_OK opon successfully updating the
** system call pointer, or SQLITE_NOTFOUND if there is no configurable
** system call named zName.
................................................................................
/******************* End of the no-op lock implementation *********************
******************************************************************************/
/******************************************************************************
************************* Begin dot-file Locking ******************************
**
** The dotfile locking implementation uses the existance of separate lock
** files (really a directory) to control access to the database. This works
** on just about every filesystem imaginable. But there are serious downsides:
**
** (1) There is zero concurrency. A single reader blocks all other
** connections from reading or writing the database.
**
** (2) An application crash or power loss can leave stale lock files
** sitting around that need to be cleared manually.
**
** Nevertheless, a dotlock is an appropriate locking mode for use if no
** other locking strategy is available.
**
** Dotfile locking works by creating a subdirectory in the same directory as
** the database and with the same name but with a ".lock" extension added.
** The existance of a lock directory implies an EXCLUSIVE lock. All other
** lock types (SHARED, RESERVED, PENDING) are mapped into EXCLUSIVE.
*/
/*
** The file suffix added to the data base filename in order to create the
** lock directory.
*/
#define DOTLOCK_SUFFIX ".lock"
/*
** 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, set *pResOut
** to a non-zero value otherwise *pResOut is set to zero. The return value
................................................................................
** routine to lower a locking level.
**
** With dotfile locking, we really only support state (4): EXCLUSIVE.
** But we track the other locking levels internally.
*/
static int dotlockLock(sqlite3_file *id, int eFileLock) {
unixFile *pFile = (unixFile*)id;
char *zLockFile = (char *)pFile->lockingContext;
int rc = SQLITE_OK;
/* If we have any lock, then the lock file already exists. All we have
** to do is adjust our internal record of the lock level.
*/
................................................................................
#else
utimes(zLockFile, NULL);
#endif
return SQLITE_OK;
}
/* grab an exclusive lock */
rc = osMkdir(zLockFile, 0777);
if( rc<0 ){
/* failed to open/create the lock directory */
int tErrno = errno;
if( EEXIST == tErrno ){
rc = SQLITE_BUSY;
} else {
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
}
}
return rc;
}
/* got it, set the type and return ok */
pFile->eFileLock = eFileLock;
return rc;
}
/*
................................................................................
** the requested locking level, this routine is a no-op.
**
** When the locking level reaches NO_LOCK, delete the lock file.
*/
static int dotlockUnlock(sqlite3_file *id, int eFileLock) {
unixFile *pFile = (unixFile*)id;
char *zLockFile = (char *)pFile->lockingContext;
int rc;
assert( pFile );
OSTRACE(("UNLOCK %d %d was %d pid=%d (dotlock)\n", pFile->h, eFileLock,
pFile->eFileLock, getpid()));
assert( eFileLock<=SHARED_LOCK );
/* no-op if possible */
................................................................................
if( eFileLock==SHARED_LOCK ){
pFile->eFileLock = SHARED_LOCK;
return SQLITE_OK;
}
/* To fully unlock the database, delete the lock file */
assert( eFileLock==NO_LOCK );
rc = osRmdir(zLockFile);
if( rc<0 && errno==ENOTDIR ) rc = osUnlink(zLockFile);
if( rc<0 ){
int rc = 0;
int tErrno = errno;
if( ENOENT != tErrno ){
rc = SQLITE_IOERR_UNLOCK;
}
if( IS_LOCK_ERROR(rc) ){
pFile->lastErrno = tErrno;
................................................................................
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( osMkdir(buf, SQLITE_DEFAULT_PROXYDIR_PERMISSIONS) ){
int err=errno;
if( err!=EEXIST ) {
OSTRACE(("CREATELOCKPATH FAILED creating %s, "
"'%s' proxy lock path=%s pid=%d\n",
buf, strerror(err), lockPath, getpid()));
return err;
}
................................................................................
UNIXVFS("unix-proxy", proxyIoFinder ),
#endif
};
unsigned int i; /* Loop counter */
/* Double-check that the aSyscall[] array has been constructed
** correctly. See ticket [bb3a86e890c8e96ab] */
assert( ArraySize(aSyscall)==20 );
/* Register all VFSes defined in the aVfs[] array */
for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){
sqlite3_vfs_register(&aVfs[i], i==0);
}
return SQLITE_OK;
}
|
Changes to test/syscall.test.
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 |
#-------------------------------------------------------------------------
# Tests for the xNextSystemCall method.
#
foreach s {
open close access getcwd stat fstat ftruncate
fcntl read pread write pwrite fchmod fallocate
pread64 pwrite64 unlink openDirectory
} {
if {[test_syscall exists $s]} {lappend syscall_list $s}
}
do_test 3.1 { lsort [test_syscall list] } [lsort $syscall_list]
#-------------------------------------------------------------------------
# This test verifies that if a call to open() fails and errno is set to
|
| |
55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 |
#-------------------------------------------------------------------------
# Tests for the xNextSystemCall method.
#
foreach s {
open close access getcwd stat fstat ftruncate
fcntl read pread write pwrite fchmod fallocate
pread64 pwrite64 unlink openDirectory mkdir rmdir
} {
if {[test_syscall exists $s]} {lappend syscall_list $s}
}
do_test 3.1 { lsort [test_syscall list] } [lsort $syscall_list]
#-------------------------------------------------------------------------
# This test verifies that if a call to open() fails and errno is set to
|