#include "tdb_private.h"
-#define TDB_MARK_LOCK 0x80000000
-
void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
{
tdb->interrupt_sig_ptr = ptr;
}
+static int fcntl_lock(struct tdb_context *tdb,
+ int rw, off_t off, off_t len, bool wait)
+{
+ struct flock fl;
+
+ fl.l_type = rw;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = off;
+ fl.l_len = len;
+ fl.l_pid = 0;
+
+ if (wait)
+ return fcntl(tdb->fd, F_SETLKW, &fl);
+ else
+ return fcntl(tdb->fd, F_SETLK, &fl);
+}
+
+static int fcntl_unlock(struct tdb_context *tdb, int rw, off_t off, off_t len)
+{
+ struct flock fl;
+#if 0 /* Check they matched up locks and unlocks correctly. */
+ char line[80];
+ FILE *locks;
+ bool found = false;
+
+ locks = fopen("/proc/locks", "r");
+
+ while (fgets(line, 80, locks)) {
+ char *p;
+ int type, start, l;
+
+ /* eg. 1: FLOCK ADVISORY WRITE 2440 08:01:2180826 0 EOF */
+ p = strchr(line, ':') + 1;
+ if (strncmp(p, " POSIX ADVISORY ", strlen(" POSIX ADVISORY ")))
+ continue;
+ p += strlen(" FLOCK ADVISORY ");
+ if (strncmp(p, "READ ", strlen("READ ")) == 0)
+ type = F_RDLCK;
+ else if (strncmp(p, "WRITE ", strlen("WRITE ")) == 0)
+ type = F_WRLCK;
+ else
+ abort();
+ p += 6;
+ if (atoi(p) != getpid())
+ continue;
+ p = strchr(strchr(p, ' ') + 1, ' ') + 1;
+ start = atoi(p);
+ p = strchr(p, ' ') + 1;
+ if (strncmp(p, "EOF", 3) == 0)
+ l = 0;
+ else
+ l = atoi(p) - start + 1;
+
+ if (off == start) {
+ if (len != l) {
+ fprintf(stderr, "Len %u should be %u: %s",
+ (int)len, l, line);
+ abort();
+ }
+ if (type != rw) {
+ fprintf(stderr, "Type %s wrong: %s",
+ rw == F_RDLCK ? "READ" : "WRITE", line);
+ abort();
+ }
+ found = true;
+ break;
+ }
+ }
+
+ if (!found) {
+ fprintf(stderr, "Unlock on %u@%u not found!\n",
+ (int)off, (int)len);
+ abort();
+ }
+
+ fclose(locks);
+#endif
+
+ fl.l_type = F_UNLCK;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = off;
+ fl.l_len = len;
+ fl.l_pid = 0;
+
+ return fcntl(tdb->fd, F_SETLKW, &fl);
+}
+
/* a byte range locking function - return 0 on success
this functions locks/unlocks 1 byte at the specified offset.
note that a len of zero means lock to end of file
*/
-int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset,
- int rw_type, int lck_type, int probe, size_t len)
+int tdb_brlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len,
+ enum tdb_lock_flags flags)
{
- struct flock fl;
int ret;
if (tdb->flags & TDB_NOLOCK) {
return 0;
}
+ if (flags & TDB_LOCK_MARK_ONLY) {
+ return 0;
+ }
+
if ((rw_type == F_WRLCK) && (tdb->read_only || tdb->traverse_read)) {
tdb->ecode = TDB_ERR_RDONLY;
return -1;
}
- fl.l_type = rw_type;
- fl.l_whence = SEEK_SET;
- fl.l_start = offset;
- fl.l_len = len;
- fl.l_pid = 0;
-
do {
- ret = fcntl(tdb->fd,lck_type,&fl);
-
+ ret = fcntl_lock(tdb, rw_type, offset, len,
+ flags & TDB_LOCK_WAIT);
/* Check for a sigalarm break. */
if (ret == -1 && errno == EINTR &&
tdb->interrupt_sig_ptr &&
/* Generic lock error. errno set by fcntl.
* EAGAIN is an expected return from non-blocking
* locks. */
- if (!probe && lck_type != F_SETLK) {
+ if (!(flags & TDB_LOCK_PROBE) && errno != EAGAIN) {
/* Ensure error code is set for log fun to examine. */
tdb->ecode = TDB_ERR_LOCK;
- TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d lck_type=%d len=%d\n",
- tdb->fd, offset, rw_type, lck_type, (int)len));
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d flags=%d len=%d\n",
+ tdb->fd, offset, rw_type, flags, (int)len));
}
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ return -1;
}
return 0;
}
+int tdb_brunlock(struct tdb_context *tdb,
+ int rw_type, tdb_off_t offset, size_t len)
+{
+ int ret;
+
+ if (tdb->flags & TDB_NOLOCK) {
+ return 0;
+ }
+
+ do {
+ ret = fcntl_unlock(tdb, rw_type, offset, len);
+ } while (ret == -1 && errno == EINTR);
+
+ if (ret == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brunlock failed (fd=%d) at offset %d rw_type=%d len=%d\n",
+ tdb->fd, offset, rw_type, (int)len));
+ }
+ return ret;
+}
/*
upgrade a read lock to a write lock. This needs to be handled in a
int count = 1000;
while (count--) {
struct timeval tv;
- if (tdb_brlock(tdb, offset, F_WRLCK, F_SETLKW, 1, len) == 0) {
+ if (tdb_brlock(tdb, F_WRLCK, offset, len,
+ TDB_LOCK_WAIT|TDB_LOCK_PROBE) == 0) {
return 0;
}
if (errno != EDEADLK) {
/* lock a list in the database. list -1 is the alloc list */
-static int _tdb_lock(struct tdb_context *tdb, int list, int ltype, int op)
+static int _tdb_lock(struct tdb_context *tdb, int list, int ltype,
+ enum tdb_lock_flags flags)
{
struct tdb_lock_type *new_lck;
int i;
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
/* a global lock allows us to avoid per chain locks */
if (tdb->global_lock.count &&
}
if (tdb->global_lock.count) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
if (list < -1 || list >= (int)tdb->header.hash_size) {
+ tdb->ecode = TDB_ERR_LOCK;
TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid list %d for ltype=%d\n",
list, ltype));
return -1;
/* Since fcntl locks don't nest, we do a lock for the first one,
and simply bump the count for future ones */
- if (!mark_lock &&
- tdb->methods->tdb_brlock(tdb,FREELIST_TOP+4*list, ltype, op,
- 0, 1)) {
+ if (tdb->methods->brlock(tdb, ltype, FREELIST_TOP+4*list, 1, flags)) {
return -1;
}
int tdb_lock(struct tdb_context *tdb, int list, int ltype)
{
int ret;
- ret = _tdb_lock(tdb, list, ltype, F_SETLKW);
+
+ ret = _tdb_lock(tdb, list, ltype, TDB_LOCK_WAIT);
if (ret) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d "
"ltype=%d (%s)\n", list, ltype, strerror(errno)));
/* lock a list in the database. list -1 is the alloc list. non-blocking lock */
int tdb_lock_nonblock(struct tdb_context *tdb, int list, int ltype)
{
- return _tdb_lock(tdb, list, ltype, F_SETLK);
+ return _tdb_lock(tdb, list, ltype, TDB_LOCK_NOWAIT);
}
-/* unlock the database: returns void because it's too late for errors. */
- /* changed to return int it may be interesting to know there
- has been an error --simo */
-int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
+static int _tdb_unlock(struct tdb_context *tdb, int list, int ltype,
+ bool mark_lock)
{
int ret = -1;
int i;
struct tdb_lock_type *lck = NULL;
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
/* a global lock allows us to avoid per chain locks */
if (tdb->global_lock.count &&
}
if (tdb->global_lock.count) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
if (tdb->flags & TDB_NOLOCK)
if (mark_lock) {
ret = 0;
} else {
- ret = tdb->methods->tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK,
- F_SETLKW, 0, 1);
+ ret = tdb->methods->brunlock(tdb, ltype,
+ FREELIST_TOP+4*list, 1);
}
tdb->num_locks--;
return ret;
}
+int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
+{
+ return _tdb_unlock(tdb, list, ltype, false);
+}
+
/*
get the transaction lock
*/
int tdb_transaction_lock(struct tdb_context *tdb, int ltype)
{
- if (tdb->have_transaction_lock || tdb->global_lock.count) {
- tdb->have_transaction_lock++;
+ if (tdb->global_lock.count) {
return 0;
}
- if (tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, ltype,
- F_SETLKW, 0, 1) == -1) {
+ if (tdb->transaction_lock_count > 0) {
+ tdb->transaction_lock_count++;
+ return 0;
+ }
+
+ if (tdb->methods->brlock(tdb, ltype, TRANSACTION_LOCK, 1, TDB_LOCK_WAIT) == -1) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_transaction_lock: failed to get transaction lock\n"));
tdb->ecode = TDB_ERR_LOCK;
return -1;
}
- tdb->have_transaction_lock++;
+ tdb->transaction_lock_count++;
return 0;
}
/*
release the transaction lock
*/
-int tdb_transaction_unlock(struct tdb_context *tdb)
+int tdb_transaction_unlock(struct tdb_context *tdb, int ltype)
{
- if (--tdb->have_transaction_lock) {
+ int ret;
+ if (tdb->global_lock.count) {
+ return 0;
+ }
+ if (tdb->transaction_lock_count > 1) {
+ tdb->transaction_lock_count--;
return 0;
}
- return tdb->methods->tdb_brlock(tdb, TRANSACTION_LOCK, F_UNLCK, F_SETLKW, 0, 1);
+ ret = tdb->methods->brunlock(tdb, ltype, TRANSACTION_LOCK, 1);
+ if (ret == 0) {
+ tdb->transaction_lock_count = 0;
+ }
+ return ret;
}
/* lock/unlock entire database */
-static int _tdb_lockall(struct tdb_context *tdb, int ltype, int op)
+static int _tdb_lockall(struct tdb_context *tdb, int ltype,
+ enum tdb_lock_flags flags)
{
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
-
/* There are no locks on read-only dbs */
- if (tdb->read_only || tdb->traverse_read)
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ if (tdb->read_only || tdb->traverse_read) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
if (tdb->global_lock.count && tdb->global_lock.ltype == ltype) {
tdb->global_lock.count++;
if (tdb->global_lock.count) {
/* a global lock of a different type exists */
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
if (tdb->num_locks != 0) {
/* can't combine global and chain locks */
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
- if (!mark_lock &&
- tdb->methods->tdb_brlock(tdb, FREELIST_TOP, ltype, op,
- 0, 4*tdb->header.hash_size)) {
- if (op == F_SETLKW) {
+ if (tdb->methods->brlock(tdb, ltype,
+ FREELIST_TOP, 4*tdb->header.hash_size,
+ flags)) {
+ if (flags & TDB_LOCK_WAIT) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno)));
}
return -1;
/* unlock entire db */
-static int _tdb_unlockall(struct tdb_context *tdb, int ltype)
+static int _tdb_unlockall(struct tdb_context *tdb, int ltype, bool mark_lock)
{
- bool mark_lock = ((ltype & TDB_MARK_LOCK) == TDB_MARK_LOCK);
-
- ltype &= ~TDB_MARK_LOCK;
-
/* There are no locks on read-only dbs */
if (tdb->read_only || tdb->traverse_read) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
if (tdb->global_lock.ltype != ltype || tdb->global_lock.count == 0) {
- return TDB_ERRCODE(TDB_ERR_LOCK, -1);
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
}
if (tdb->global_lock.count > 1) {
}
if (!mark_lock &&
- tdb->methods->tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW,
- 0, 4*tdb->header.hash_size)) {
+ tdb->methods->brunlock(tdb, ltype,
+ FREELIST_TOP, 4*tdb->header.hash_size)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno)));
return -1;
}
int tdb_lockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall");
- return _tdb_lockall(tdb, F_WRLCK, F_SETLKW);
+ return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_WAIT);
}
/* lock entire database with write lock - mark only */
int tdb_lockall_mark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_mark");
- return _tdb_lockall(tdb, F_WRLCK | TDB_MARK_LOCK, F_SETLKW);
+ return _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_MARK_ONLY);
}
/* unlock entire database with write lock - unmark only */
int tdb_lockall_unmark(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_unmark");
- return _tdb_unlockall(tdb, F_WRLCK | TDB_MARK_LOCK);
+ return _tdb_unlockall(tdb, F_WRLCK, true);
}
/* lock entire database with write lock - nonblocking varient */
int tdb_lockall_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_WRLCK, F_SETLK);
+ int ret = _tdb_lockall(tdb, F_WRLCK, TDB_LOCK_NOWAIT);
tdb_trace_ret(tdb, "tdb_lockall_nonblock", ret);
return ret;
}
int tdb_unlockall(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall");
- return _tdb_unlockall(tdb, F_WRLCK);
+ return _tdb_unlockall(tdb, F_WRLCK, false);
}
/* lock entire database with read lock */
int tdb_lockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_lockall_read");
- return _tdb_lockall(tdb, F_RDLCK, F_SETLKW);
+ return _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_WAIT);
}
/* lock entire database with read lock - nonblock varient */
int tdb_lockall_read_nonblock(struct tdb_context *tdb)
{
- int ret = _tdb_lockall(tdb, F_RDLCK, F_SETLK);
+ int ret = _tdb_lockall(tdb, F_RDLCK, TDB_LOCK_NOWAIT);
tdb_trace_ret(tdb, "tdb_lockall_read_nonblock", ret);
return ret;
}
int tdb_unlockall_read(struct tdb_context *tdb)
{
tdb_trace(tdb, "tdb_unlockall_read");
- return _tdb_unlockall(tdb, F_RDLCK);
+ return _tdb_unlockall(tdb, F_RDLCK, false);
}
/* lock/unlock one hash chain. This is meant to be used to reduce
/* mark a chain as locked without actually locking it. Warning! use with great caution! */
int tdb_chainlock_mark(struct tdb_context *tdb, TDB_DATA key)
{
- int ret = tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK);
+ int ret = _tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK,
+ TDB_LOCK_MARK_ONLY);
tdb_trace_1rec(tdb, "tdb_chainlock_mark", key);
return ret;
}
int tdb_chainlock_unmark(struct tdb_context *tdb, TDB_DATA key)
{
tdb_trace_1rec(tdb, "tdb_chainlock_unmark", key);
- return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK | TDB_MARK_LOCK);
+ return _tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK, true);
}
int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
if (tdb->global_lock.count) {
return 0;
}
- return off ? tdb->methods->tdb_brlock(tdb, off, F_RDLCK, F_SETLKW, 0, 1) : 0;
+ return off ? tdb->methods->brlock(tdb, F_RDLCK, off, 1, TDB_LOCK_WAIT) : 0;
}
/*
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
return -1;
- return tdb->methods->tdb_brlock(tdb, off, F_WRLCK, F_SETLK, 1, 1);
+ return tdb->methods->brlock(tdb, F_WRLCK, off, 1, TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);
}
-/*
- Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not
- an error to fail to get the lock here.
-*/
int tdb_write_unlock_record(struct tdb_context *tdb, tdb_off_t off)
{
- return tdb->methods->tdb_brlock(tdb, off, F_UNLCK, F_SETLK, 0, 1);
+ return tdb->methods->brunlock(tdb, F_WRLCK, off, 1);
}
/* fcntl locks don't stack: avoid unlocking someone else's */
for (i = &tdb->travlocks; i; i = i->next)
if (i->off == off)
count++;
- return (count == 1 ? tdb->methods->tdb_brlock(tdb, off, F_UNLCK, F_SETLKW, 0, 1) : 0);
+ return (count == 1 ? tdb->methods->brunlock(tdb, F_RDLCK, off, 1) : 0);
}
projects / ccan / blobdiff