aboutsummaryrefslogtreecommitdiff
path: root/src/os_unix.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/os_unix.c')
-rw-r--r--src/os_unix.c77
1 files changed, 62 insertions, 15 deletions
diff --git a/src/os_unix.c b/src/os_unix.c
index 0d72802bd..c373ebee6 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -206,6 +206,7 @@ struct unixFile {
int h; /* The file descriptor */
int dirfd; /* File descriptor for the directory */
unsigned char eFileLock; /* The type of lock held on this fd */
+ unsigned char ctrlFlags; /* Behavioral bits. UNIXFILE_* flags */
int lastErrno; /* The unix errno from last I/O error */
void *lockingContext; /* Locking style specific state */
UnixUnusedFd *pUnused; /* Pre-allocated UnixUnusedFd */
@@ -243,6 +244,11 @@ struct unixFile {
};
/*
+** Allowed values for the unixFile.ctrlFlags bitmask:
+*/
+#define UNIXFILE_EXCL 0x01 /* Connections from one process only */
+
+/*
** Include code that is common to all os_*.c files
*/
#include "os_common.h"
@@ -887,7 +893,8 @@ struct unixFileId {
struct unixInodeInfo {
struct unixFileId fileId; /* The lookup key */
int nShared; /* Number of SHARED locks held */
- int eFileLock; /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+ unsigned char eFileLock; /* One of SHARED_LOCK, RESERVED_LOCK etc. */
+ unsigned char bProcessLock; /* An exclusive process lock is held */
int nRef; /* Number of pointers to this structure */
unixShmNode *pShmNode; /* Shared memory associated with this inode */
int nLock; /* Number of outstanding file locks */
@@ -1158,7 +1165,7 @@ static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
/* Otherwise see if some other process holds it.
*/
#ifndef __DJGPP__
- if( !reserved ){
+ if( !reserved && !pFile->pInode->bProcessLock ){
struct flock lock;
lock.l_whence = SEEK_SET;
lock.l_start = RESERVED_BYTE;
@@ -1182,6 +1189,40 @@ static int unixCheckReservedLock(sqlite3_file *id, int *pResOut){
}
/*
+** Attempt to set a system-lock on the file pFile. The lock is
+** described by pLock.
+**
+** If the pFile was opened from unix-excl, then the only lock ever
+** obtained is an exclusive lock, and it is obtained exactly once
+** the first time any lock is attempted. All subsequent system locking
+** operations become no-ops. Locking operations still happen internally,
+** in order to coordinate access between separate database connections
+** within this process, but all of that is handled in memory and the
+** operating system does not participate.
+*/
+static int unixFileLock(unixFile *pFile, struct flock *pLock){
+ int rc;
+ assert( unixMutexHeld() );
+ if( (pFile->ctrlFlags & UNIXFILE_EXCL)!=0 || pFile->pInode->bProcessLock ){
+ if( pFile->pInode->bProcessLock==0 ){
+ struct flock lock;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = SHARED_FIRST;
+ lock.l_len = SHARED_SIZE;
+ lock.l_type = F_WRLCK;
+ rc = osFcntl(pFile->h, F_SETLK, &lock);
+ if( rc<0 ) return rc;
+ pFile->pInode->bProcessLock = 1;
+ }else{
+ rc = 0;
+ }
+ }else{
+ rc = osFcntl(pFile->h, F_SETLK, pLock);
+ }
+ return rc;
+}
+
+/*
** Lock the file with the lock specified by parameter eFileLock - one
** of the following:
**
@@ -1317,7 +1358,7 @@ static int unixLock(sqlite3_file *id, int eFileLock){
){
lock.l_type = (eFileLock==SHARED_LOCK?F_RDLCK:F_WRLCK);
lock.l_start = PENDING_BYTE;
- s = osFcntl(pFile->h, F_SETLK, &lock);
+ s = unixFileLock(pFile, &lock);
if( s==(-1) ){
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
@@ -1339,14 +1380,14 @@ static int unixLock(sqlite3_file *id, int eFileLock){
/* Now get the read-lock */
lock.l_start = SHARED_FIRST;
lock.l_len = SHARED_SIZE;
- if( (s = osFcntl(pFile->h, F_SETLK, &lock))==(-1) ){
+ if( (s = unixFileLock(pFile, &lock))==(-1) ){
tErrno = errno;
}
/* Drop the temporary PENDING lock */
lock.l_start = PENDING_BYTE;
lock.l_len = 1L;
lock.l_type = F_UNLCK;
- if( osFcntl(pFile->h, F_SETLK, &lock)!=0 ){
+ if( unixFileLock(pFile, &lock)!=0 ){
if( s != -1 ){
/* This could happen with a network mount */
tErrno = errno;
@@ -1389,7 +1430,7 @@ static int unixLock(sqlite3_file *id, int eFileLock){
default:
assert(0);
}
- s = osFcntl(pFile->h, F_SETLK, &lock);
+ s = unixFileLock(pFile, &lock);
if( s==(-1) ){
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_LOCK);
@@ -1458,7 +1499,7 @@ static void setPendingFd(unixFile *pFile){
** 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 _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
+static int posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
unixFile *pFile = (unixFile*)id;
unixInodeInfo *pInode;
struct flock lock;
@@ -1525,7 +1566,7 @@ static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
lock.l_whence = SEEK_SET;
lock.l_start = SHARED_FIRST;
lock.l_len = divSize;
- if( osFcntl(h, F_SETLK, &lock)==(-1) ){
+ if( unixFileLock(pFile,, &lock)==(-1) ){
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
@@ -1537,7 +1578,7 @@ static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
lock.l_whence = SEEK_SET;
lock.l_start = SHARED_FIRST;
lock.l_len = divSize;
- if( osFcntl(h, F_SETLK, &lock)==(-1) ){
+ if( unixFileLock(pFile, &lock)==(-1) ){
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
if( IS_LOCK_ERROR(rc) ){
@@ -1549,7 +1590,7 @@ static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
lock.l_whence = SEEK_SET;
lock.l_start = SHARED_FIRST+divSize;
lock.l_len = SHARED_SIZE-divSize;
- if( osFcntl(h, F_SETLK, &lock)==(-1) ){
+ if( unixFileLock(pFile, &lock)==(-1) ){
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_UNLOCK);
if( IS_LOCK_ERROR(rc) ){
@@ -1564,7 +1605,7 @@ static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
lock.l_whence = SEEK_SET;
lock.l_start = SHARED_FIRST;
lock.l_len = SHARED_SIZE;
- if( osFcntl(h, F_SETLK, &lock)==(-1) ){
+ if( unixFileLock(pFile, &lock)==(-1) ){
tErrno = errno;
rc = sqliteErrorFromPosixError(tErrno, SQLITE_IOERR_RDLOCK);
if( IS_LOCK_ERROR(rc) ){
@@ -1578,7 +1619,7 @@ static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
lock.l_whence = SEEK_SET;
lock.l_start = PENDING_BYTE;
lock.l_len = 2L; assert( PENDING_BYTE+1==RESERVED_BYTE );
- if( osFcntl(h, F_SETLK, &lock)!=(-1) ){
+ if( unixFileLock(pFile, &lock)!=(-1) ){
pInode->eFileLock = SHARED_LOCK;
}else{
tErrno = errno;
@@ -1602,7 +1643,7 @@ static int _posixUnlock(sqlite3_file *id, int eFileLock, int handleNFSUnlock){
SimulateIOErrorBenign(1);
SimulateIOError( h=(-1) )
SimulateIOErrorBenign(0);
- if( osFcntl(h, F_SETLK, &lock)!=(-1) ){
+ if( unixFileLock(pFile, &lock)!=(-1) ){
pInode->eFileLock = NO_LOCK;
}else{
tErrno = errno;
@@ -1640,7 +1681,7 @@ end_unlock:
** the requested locking level, this routine is a no-op.
*/
static int unixUnlock(sqlite3_file *id, int eFileLock){
- return _posixUnlock(id, eFileLock, 0);
+ return posixUnlock(id, eFileLock, 0);
}
/*
@@ -2821,7 +2862,7 @@ static int afpClose(sqlite3_file *id) {
** the requested locking level, this routine is a no-op.
*/
static int nfsUnlock(sqlite3_file *id, int eFileLock){
- return _posixUnlock(id, eFileLock, 1);
+ return posixUnlock(id, eFileLock, 1);
}
#endif /* defined(__APPLE__) && SQLITE_ENABLE_LOCKING_STYLE */
@@ -4351,6 +4392,11 @@ static int fillInUnixFile(
pNew->h = h;
pNew->dirfd = dirfd;
pNew->zPath = zFilename;
+ if( memcmp(pVfs->zName,"unix-excl",10)==0 ){
+ pNew->ctrlFlags = UNIXFILE_EXCL;
+ }else{
+ pNew->ctrlFlags = 0;
+ }
#if OS_VXWORKS
pNew->pId = vxworksFindFileId(zFilename);
@@ -6550,6 +6596,7 @@ int sqlite3_os_init(void){
#endif
UNIXVFS("unix-none", nolockIoFinder ),
UNIXVFS("unix-dotfile", dotlockIoFinder ),
+ UNIXVFS("unix-excl", posixIoFinder ),
#if OS_VXWORKS
UNIXVFS("unix-namedsem", semIoFinder ),
#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-20 20:24:58 +0000