/* traverse the entire database - calling fn(tdb, key, data) on each element.
return -1 on error or the record count traversed
if fn is NULL then it is not called
a non-zero return value from fn() indicates that the traversal should stop
*/
static int tdb_traverse_internal(struct tdb_context *tdb,
tdb_traverse_func fn, void *private_data,
struct tdb_traverse_lock *tl)
{
TDB_DATA key, dbuf;
struct list_struct rec;
int ret, count = 0;
/* This was in the initializaton, above, but the IRIX compiler
* did not like it. crh
*/
tl->next = tdb->travlocks.next;
/* fcntl locks don't stack: beware traverse inside traverse */
tdb->travlocks.next = tl;
/* tdb_next_lock places locks on the record returned, and its chain */
while ((ret = tdb_next_lock(tdb, tl, &rec)) > 0) {
count++;
/* now read the full record */
key.dptr = tdb_alloc_read(tdb, tl->off + sizeof(rec),
rec.key_len + rec.data_len);
if (!key.dptr) {
ret = -1;
if (tdb_unlock(tdb, tl->hash, tl->lock_rw) != 0)
goto out;
if (tdb_unlock_record(tdb, tl->off) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_traverse: key.dptr == NULL and unlock_record failed!\n"));
goto out;
}
key.dsize = rec.key_len;
dbuf.dptr = key.dptr + rec.key_len;
dbuf.dsize = rec.data_len;
/* Drop chain lock, call out */
if (tdb_unlock(tdb, tl->hash, tl->lock_rw) != 0) {
ret = -1;
SAFE_FREE(key.dptr);
goto out;
}
if (fn && fn(tdb, key, dbuf, private_data)) {
/* They want us to terminate traversal */
ret = count;
if (tdb_unlock_record(tdb, tl->off) != 0) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_traverse: unlock_record failed!\n"));;
ret = -1;
}
SAFE_FREE(key.dptr);
goto out;
}
SAFE_FREE(key.dptr);
}
out:
tdb->travlocks.next = tl->next;
if (ret < 0)
return -1;
else
return count;
}
/* find the first entry in the database and return its key */
_PUBLIC_ TDB_DATA tdb_firstkey(struct tdb_context *tdb)
{
TDB_DATA key;
struct tdb_record rec;
tdb_off_t off;
/* release any old lock */
if (tdb_unlock_record(tdb, tdb->travlocks.off) != 0)
return tdb_null;
tdb->travlocks.off = tdb->travlocks.list = 0;
tdb->travlocks.lock_rw = F_RDLCK;
/* Grab first record: locks chain and returned record. */
off = tdb_next_lock(tdb, &tdb->travlocks, &rec);
if (off == 0 || off == TDB_NEXT_LOCK_ERR) {
tdb_trace_retrec(tdb, "tdb_firstkey", tdb_null);
return tdb_null;
}
/* now read the key */
key.dsize = rec.key_len;
key.dptr =tdb_alloc_read(tdb,tdb->travlocks.off+sizeof(rec),key.dsize);
tdb_trace_retrec(tdb, "tdb_firstkey", key);
/* Unlock the hash chain of the record we just read. */
if (tdb_unlock(tdb, tdb->travlocks.list, tdb->travlocks.lock_rw) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_firstkey: error occurred while tdb_unlocking!\n"));
return key;
}
/* find the next entry in the database, returning its key */
TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA oldkey)
{
u32 oldhash;
TDB_DATA key = tdb_null;
struct list_struct rec;
char *k = NULL;
/* Is locked key the old key? If so, traverse will be reliable. */
if (tdb->travlocks.off) {
if (tdb_lock(tdb,tdb->travlocks.hash,tdb->travlocks.lock_rw))
return tdb_null;
if (tdb_rec_read(tdb, tdb->travlocks.off, &rec) == -1
|| !(k = tdb_alloc_read(tdb,tdb->travlocks.off+sizeof(rec),
rec.key_len))
|| memcmp(k, oldkey.dptr, oldkey.dsize) != 0) {
/* No, it wasn't: unlock it and start from scratch */
if (tdb_unlock_record(tdb, tdb->travlocks.off) != 0) {
SAFE_FREE(k);
return tdb_null;
}
if (tdb_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0) {
SAFE_FREE(k);
return tdb_null;
}
tdb->travlocks.off = 0;
}
SAFE_FREE(k);
}
if (!tdb->travlocks.off) {
/* No previous element: do normal find, and lock record */
tdb->travlocks.off = tdb_find_lock_hash(tdb, oldkey, tdb->hash_fn(&oldkey), tdb->travlocks.lock_rw, &rec);
if (!tdb->travlocks.off)
return tdb_null;
tdb->travlocks.hash = BUCKET(rec.full_hash);
if (tdb_lock_record(tdb, tdb->travlocks.off) != 0) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_nextkey: lock_record failed (%s)!\n", strerror(errno)));
return tdb_null;
}
}
oldhash = tdb->travlocks.hash;
/* Grab next record: locks chain and returned record,
unlocks old record */
if (tdb_next_lock(tdb, &tdb->travlocks, &rec) > 0) {
key.dsize = rec.key_len;
key.dptr = tdb_alloc_read(tdb, tdb->travlocks.off+sizeof(rec),
key.dsize);
/* Unlock the chain of this new record */
if (tdb_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_nextkey: WARNING tdb_unlock failed!\n"));
}
/* Unlock the chain of old record */
if (tdb_unlock(tdb, BUCKET(oldhash), tdb->travlocks.lock_rw) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_nextkey: WARNING tdb_unlock failed!\n"));
return key;
}
/* find the first entry in the database and return its key */
TDB_DATA tdb_firstkey(struct tdb_context *tdb)
{
TDB_DATA key;
struct list_struct rec;
/* release any old lock */
if (tdb_unlock_record(tdb, tdb->travlocks.off) != 0)
return tdb_null;
tdb->travlocks.off = tdb->travlocks.hash = 0;
tdb->travlocks.lock_rw = F_RDLCK;
/* Grab first record: locks chain and returned record. */
if (tdb_next_lock(tdb, &tdb->travlocks, &rec) <= 0)
return tdb_null;
/* now read the key */
key.dsize = rec.key_len;
key.dptr =tdb_alloc_read(tdb,tdb->travlocks.off+sizeof(rec),key.dsize);
/* Unlock the hash chain of the record we just read. */
if (tdb_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_firstkey: error occurred while tdb_unlocking!\n"));
return key;
}
/* Uses traverse lock: 0 = finish, TDB_NEXT_LOCK_ERR = error,
other = record offset */
static tdb_off_t tdb_next_lock(struct tdb_context *tdb, struct tdb_traverse_lock *tlock,
struct tdb_record *rec)
{
int want_next = (tlock->off != 0);
/* Lock each chain from the start one. */
for (; tlock->list < tdb->hash_size; tlock->list++) {
if (!tlock->off && tlock->list != 0) {
/* this is an optimisation for the common case where
the hash chain is empty, which is particularly
common for the use of tdb with ldb, where large
hashes are used. In that case we spend most of our
time in tdb_brlock(), locking empty hash chains.
To avoid this, we do an unlocked pre-check to see
if the hash chain is empty before starting to look
inside it. If it is empty then we can avoid that
hash chain. If it isn't empty then we can't believe
the value we get back, as we read it without a
lock, so instead we get the lock and re-fetch the
value below.
Notice that not doing this optimisation on the
first hash chain is critical. We must guarantee
that we have done at least one fcntl lock at the
start of a search to guarantee that memory is
coherent on SMP systems. If records are added by
others during the search then thats OK, and we
could possibly miss those with this trick, but we
could miss them anyway without this trick, so the
semantics don't change.
With a non-indexed ldb search this trick gains us a
factor of around 80 in speed on a linux 2.6.x
system (testing using ldbtest).
*/
tdb->methods->next_hash_chain(tdb, &tlock->list);
if (tlock->list == tdb->hash_size) {
continue;
}
}
if (tdb_lock(tdb, tlock->list, tlock->lock_rw) == -1)
return TDB_NEXT_LOCK_ERR;
/* No previous record? Start at top of chain. */
if (!tlock->off) {
if (tdb_ofs_read(tdb, TDB_HASH_TOP(tlock->list),
&tlock->off) == -1)
goto fail;
} else {
/* Otherwise unlock the previous record. */
if (tdb_unlock_record(tdb, tlock->off) != 0)
goto fail;
}
if (want_next) {
/* We have offset of old record: grab next */
if (tdb_rec_read(tdb, tlock->off, rec) == -1)
goto fail;
tlock->off = rec->next;
}
/* Iterate through chain */
while( tlock->off) {
tdb_off_t current;
if (tdb_rec_read(tdb, tlock->off, rec) == -1)
goto fail;
/* Detect infinite loops. From "Shlomi Yaakobovich" <*****@*****.**>. */
if (tlock->off == rec->next) {
tdb->ecode = TDB_ERR_CORRUPT;
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_next_lock: loop detected.\n"));
goto fail;
}
if (!TDB_DEAD(rec)) {
/* Woohoo: we found one! */
if (tdb_lock_record(tdb, tlock->off) != 0)
goto fail;
return tlock->off;
}
/* Try to clean dead ones from old traverses */
current = tlock->off;
tlock->off = rec->next;
if (!(tdb->read_only || tdb->traverse_read) &&
tdb_do_delete(tdb, current, rec) != 0)
goto fail;
}
tdb_unlock(tdb, tlock->list, tlock->lock_rw);
want_next = 0;
}
/* We finished iteration without finding anything */
tdb->ecode = TDB_SUCCESS;
return 0;
fail:
tlock->off = 0;
if (tdb_unlock(tdb, tlock->list, tlock->lock_rw) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_next_lock: On error unlock failed!\n"));
return TDB_NEXT_LOCK_ERR;
}
/* traverse the entire database - calling fn(tdb, key, data) on each element.
return -1 on error or the record count traversed
if fn is NULL then it is not called
a non-zero return value from fn() indicates that the traversal should stop
*/
static int tdb_traverse_internal(struct tdb_context *tdb,
tdb_traverse_func fn, void *private_data,
struct tdb_traverse_lock *tl)
{
TDB_DATA key, dbuf;
struct tdb_record rec;
int ret = 0, count = 0;
tdb_off_t off;
size_t recbuf_len;
recbuf_len = 4096;
key.dptr = malloc(recbuf_len);
if (key.dptr == NULL) {
return -1;
}
/* This was in the initialization, above, but the IRIX compiler
* did not like it. crh
*/
tl->next = tdb->travlocks.next;
/* fcntl locks don't stack: beware traverse inside traverse */
tdb->travlocks.next = tl;
/* tdb_next_lock places locks on the record returned, and its chain */
while ((off = tdb_next_lock(tdb, tl, &rec)) != 0) {
tdb_len_t full_len;
int nread;
if (off == TDB_NEXT_LOCK_ERR) {
ret = -1;
goto out;
}
full_len = rec.key_len + rec.data_len;
if (full_len > recbuf_len) {
recbuf_len = full_len;
/*
* No realloc, we don't need the old data and thus can
* do without the memcpy
*/
free(key.dptr);
key.dptr = malloc(recbuf_len);
if (key.dptr == NULL) {
ret = -1;
if (tdb_unlock(tdb, tl->list, tl->lock_rw)
!= 0) {
goto out;
}
if (tdb_unlock_record(tdb, tl->off) != 0) {
TDB_LOG((tdb, TDB_DEBUG_FATAL,
"tdb_traverse: malloc "
"failed and unlock_record "
"failed!\n"));
}
goto out;
}
}
count++;
/* now read the full record */
nread = tdb->methods->tdb_read(tdb, tl->off + sizeof(rec),
key.dptr, full_len, 0);
if (nread == -1) {
ret = -1;
if (tdb_unlock(tdb, tl->list, tl->lock_rw) != 0)
goto out;
if (tdb_unlock_record(tdb, tl->off) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_traverse: key.dptr == NULL and unlock_record failed!\n"));
goto out;
}
key.dsize = rec.key_len;
dbuf.dptr = key.dptr + rec.key_len;
dbuf.dsize = rec.data_len;
tdb_trace_1rec_retrec(tdb, "traverse", key, dbuf);
/* Drop chain lock, call out */
if (tdb_unlock(tdb, tl->list, tl->lock_rw) != 0) {
ret = -1;
goto out;
}
if (fn && fn(tdb, key, dbuf, private_data)) {
/* They want us to terminate traversal */
tdb_trace_ret(tdb, "tdb_traverse_end", count);
if (tdb_unlock_record(tdb, tl->off) != 0) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_traverse: unlock_record failed!\n"));;
ret = -1;
}
goto out;
}
}
tdb_trace(tdb, "tdb_traverse_end");
out:
SAFE_FREE(key.dptr);
tdb->travlocks.next = tl->next;
if (ret < 0)
return -1;
else
return count;
}
