#include "tdb_private.h"
void tdb_setalarm_sigptr(struct tdb_context *tdb, volatile sig_atomic_t *ptr)
{
tdb->interrupt_sig_ptr = ptr;
}
int tdb_brlock(struct tdb_context *tdb, tdb_off_t offset,
int rw_type, int lck_type, int probe, size_t len)
{
struct flock fl;
int ret;
if (tdb->flags & TDB_NOLOCK) {
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);
if (ret == -1 && errno == EINTR &&
tdb->interrupt_sig_ptr &&
*tdb->interrupt_sig_ptr) {
break;
}
} while (ret == -1 && errno == EINTR);
if (ret == -1) {
if (!probe && lck_type != F_SETLK) {
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));
}
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
return 0;
}
int tdb_brlock_upgrade(struct tdb_context *tdb, tdb_off_t offset, size_t len)
{
int count = 1000;
while (count--) {
struct timeval tv;
if (tdb_brlock(tdb, offset, F_WRLCK, F_SETLKW, 1, len) == 0) {
return 0;
}
if (errno != EDEADLK) {
break;
}
tv.tv_sec = 0;
tv.tv_usec = 1;
select(0, NULL, NULL, NULL, &tv);
}
TDB_LOG((tdb, TDB_DEBUG_TRACE,"tdb_brlock_upgrade failed at offset %d\n", offset));
return -1;
}
int tdb_lock(struct tdb_context *tdb, int list, int ltype)
{
struct tdb_lock_type *new_lck;
int i;
if (tdb->global_lock.count &&
(ltype == tdb->global_lock.ltype || ltype == F_RDLCK)) {
return 0;
}
if (tdb->global_lock.count) {
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
if (list < -1 || list >= (int)tdb->header.hash_size) {
TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_lock: invalid list %d for ltype=%d\n",
list, ltype));
return -1;
}
if (tdb->flags & TDB_NOLOCK)
return 0;
for (i=0; i<tdb->num_lockrecs; i++) {
if (tdb->lockrecs[i].list == list) {
if (tdb->lockrecs[i].count == 0) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock: "
"lck->count == 0 for list %d", list));
}
tdb->lockrecs[i].count++;
return 0;
}
}
new_lck = (struct tdb_lock_type *)realloc(
tdb->lockrecs,
sizeof(*tdb->lockrecs) * (tdb->num_lockrecs+1));
if (new_lck == NULL) {
errno = ENOMEM;
return -1;
}
tdb->lockrecs = new_lck;
if (tdb->methods->tdb_brlock(tdb,FREELIST_TOP+4*list,ltype,F_SETLKW,
0, 1)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lock failed on list %d "
"ltype=%d (%s)\n", list, ltype, strerror(errno)));
return -1;
}
tdb->num_locks++;
tdb->lockrecs[tdb->num_lockrecs].list = list;
tdb->lockrecs[tdb->num_lockrecs].count = 1;
tdb->lockrecs[tdb->num_lockrecs].ltype = ltype;
tdb->num_lockrecs += 1;
return 0;
}
int tdb_unlock(struct tdb_context *tdb, int list, int ltype)
{
int ret = -1;
int i;
struct tdb_lock_type *lck = NULL;
if (tdb->global_lock.count &&
(ltype == tdb->global_lock.ltype || ltype == F_RDLCK)) {
return 0;
}
if (tdb->global_lock.count) {
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
if (tdb->flags & TDB_NOLOCK)
return 0;
if (list < -1 || list >= (int)tdb->header.hash_size) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: list %d invalid (%d)\n", list, tdb->header.hash_size));
return ret;
}
for (i=0; i<tdb->num_lockrecs; i++) {
if (tdb->lockrecs[i].list == list) {
lck = &tdb->lockrecs[i];
break;
}
}
if ((lck == NULL) || (lck->count == 0)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: count is 0\n"));
return -1;
}
if (lck->count > 1) {
lck->count--;
return 0;
}
ret = tdb->methods->tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK,
F_SETLKW, 0, 1);
tdb->num_locks--;
if (tdb->num_lockrecs > 1) {
*lck = tdb->lockrecs[tdb->num_lockrecs-1];
}
tdb->num_lockrecs -= 1;
if (tdb->num_lockrecs == 0) {
SAFE_FREE(tdb->lockrecs);
}
if (ret)
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlock: An error occurred unlocking!\n"));
return ret;
}
static int _tdb_lockall(struct tdb_context *tdb, int ltype)
{
if (tdb->read_only || tdb->traverse_read)
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
if (tdb->global_lock.count && tdb->global_lock.ltype == ltype) {
tdb->global_lock.count++;
return 0;
}
if (tdb->global_lock.count) {
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
if (tdb->num_locks != 0) {
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
if (tdb->methods->tdb_brlock(tdb, FREELIST_TOP, ltype, F_SETLKW,
0, 4*tdb->header.hash_size)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_lockall failed (%s)\n", strerror(errno)));
return -1;
}
tdb->global_lock.count = 1;
tdb->global_lock.ltype = ltype;
return 0;
}
static int _tdb_unlockall(struct tdb_context *tdb, int ltype)
{
if (tdb->read_only || tdb->traverse_read) {
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
if (tdb->global_lock.ltype != ltype || tdb->global_lock.count == 0) {
return TDB_ERRCODE(TDB_ERR_LOCK, -1);
}
if (tdb->global_lock.count > 1) {
tdb->global_lock.count--;
return 0;
}
if (tdb->methods->tdb_brlock(tdb, FREELIST_TOP, F_UNLCK, F_SETLKW,
0, 4*tdb->header.hash_size)) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_unlockall failed (%s)\n", strerror(errno)));
return -1;
}
tdb->global_lock.count = 0;
tdb->global_lock.ltype = 0;
return 0;
}
int tdb_lockall(struct tdb_context *tdb)
{
return _tdb_lockall(tdb, F_WRLCK);
}
int tdb_unlockall(struct tdb_context *tdb)
{
return _tdb_unlockall(tdb, F_WRLCK);
}
int tdb_lockall_read(struct tdb_context *tdb)
{
return _tdb_lockall(tdb, F_RDLCK);
}
int tdb_unlockall_read(struct tdb_context *tdb)
{
return _tdb_unlockall(tdb, F_RDLCK);
}
int tdb_chainlock(struct tdb_context *tdb, TDB_DATA key)
{
return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
}
int tdb_chainunlock(struct tdb_context *tdb, TDB_DATA key)
{
return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_WRLCK);
}
int tdb_chainlock_read(struct tdb_context *tdb, TDB_DATA key)
{
return tdb_lock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
}
int tdb_chainunlock_read(struct tdb_context *tdb, TDB_DATA key)
{
return tdb_unlock(tdb, BUCKET(tdb->hash_fn(&key)), F_RDLCK);
}
int tdb_lock_record(struct tdb_context *tdb, tdb_off_t off)
{
return off ? tdb->methods->tdb_brlock(tdb, off, F_RDLCK, F_SETLKW, 0, 1) : 0;
}
int tdb_write_lock_record(struct tdb_context *tdb, tdb_off_t off)
{
struct tdb_traverse_lock *i;
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);
}
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);
}
int tdb_unlock_record(struct tdb_context *tdb, tdb_off_t off)
{
struct tdb_traverse_lock *i;
u32 count = 0;
if (off == 0)
return 0;
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);
}