- /*
+ /*
Unix SMB/CIFS implementation.
trivial database library
Copyright (C) Andrew Tridgell 1999-2005
Copyright (C) Paul `Rusty' Russell 2000
Copyright (C) Jeremy Allison 2000-2003
-
+
** NOTE! The following LGPL license applies to the tdb
** library. This does NOT imply that all of Samba is released
** under the LGPL
-
+
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
/* 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 list_struct *rec)
+ struct tdb_record *rec)
{
int want_next = (tlock->off != 0);
/* Lock each chain from the start one. */
- for (; tlock->hash < tdb->header.hash_size; tlock->hash++) {
- if (!tlock->off && tlock->hash != 0) {
+ 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
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
+ others during the search then that's 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->hash);
- if (tlock->hash == tdb->header.hash_size) {
+ tdb->methods->next_hash_chain(tdb, &tlock->list);
+ if (tlock->list == tdb->hash_size) {
continue;
}
}
- if (tdb_lock(tdb, tlock->hash, tlock->lock_rw) == -1)
+ 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->hash),
+ if (tdb_ofs_read(tdb, TDB_HASH_TOP(tlock->list),
&tlock->off) == -1)
goto fail;
} else {
/* Iterate through chain */
while( tlock->off) {
- tdb_off_t current;
if (tdb_rec_read(tdb, tlock->off, rec) == -1)
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->hash, tlock->lock_rw);
+ tdb_unlock(tdb, tlock->list, tlock->lock_rw);
want_next = 0;
}
/* We finished iteration without finding anything */
- return TDB_ERRCODE(TDB_SUCCESS, 0);
+ tdb->ecode = TDB_SUCCESS;
+ return 0;
fail:
tlock->off = 0;
- if (tdb_unlock(tdb, tlock->hash, tlock->lock_rw) != 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;
}
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,
+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;
+ 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 initializaton, above, but the IRIX compiler
+ /* This was in the initialization, above, but the IRIX compiler
* did not like it. crh
*/
tl->next = tdb->travlocks.next;
/* 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 */
- key.dptr = tdb_alloc_read(tdb, tl->off + sizeof(rec),
- rec.key_len + rec.data_len);
- if (!key.dptr) {
+ 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->hash, tl->lock_rw) != 0)
+ 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"));
tdb_trace_1rec_retrec(tdb, "traverse", key, dbuf);
/* Drop chain lock, call out */
- if (tdb_unlock(tdb, tl->hash, tl->lock_rw) != 0) {
+ if (tdb_unlock(tdb, tl->list, tl->lock_rw) != 0) {
ret = -1;
- SAFE_FREE(key.dptr);
goto out;
}
if (fn && fn(tdb, key, dbuf, private_data)) {
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_traverse: unlock_record failed!\n"));;
ret = -1;
}
- SAFE_FREE(key.dptr);
goto out;
}
- SAFE_FREE(key.dptr);
}
tdb_trace(tdb, "tdb_traverse_end");
out:
+ SAFE_FREE(key.dptr);
tdb->travlocks.next = tl->next;
if (ret < 0)
return -1;
/*
- a write style traverse - temporarily marks the db read only
+ a read style traverse - temporarily marks each record read only
*/
-int tdb_traverse_read(struct tdb_context *tdb,
+_PUBLIC_ int tdb_traverse_read(struct tdb_context *tdb,
tdb_traverse_func fn, void *private_data)
{
struct tdb_traverse_lock tl = { NULL, 0, 0, F_RDLCK };
int ret;
- /* we need to get a read lock on the transaction lock here to
- cope with the lock ordering semantics of solaris10 */
- if (tdb_transaction_lock(tdb, F_RDLCK)) {
- return -1;
- }
-
tdb->traverse_read++;
tdb_trace(tdb, "tdb_traverse_read_start");
ret = tdb_traverse_internal(tdb, fn, private_data, &tl);
tdb->traverse_read--;
- tdb_transaction_unlock(tdb);
-
return ret;
}
prevent deadlocks
WARNING: The data buffer given to the callback fn does NOT meet the
- alignment restrictions malloc gives you.
+ alignment guarantees malloc gives you.
*/
-int tdb_traverse(struct tdb_context *tdb,
+_PUBLIC_ int tdb_traverse(struct tdb_context *tdb,
tdb_traverse_func fn, void *private_data)
{
struct tdb_traverse_lock tl = { NULL, 0, 0, F_WRLCK };
+ enum tdb_lock_flags lock_flags;
int ret;
if (tdb->read_only || tdb->traverse_read) {
return tdb_traverse_read(tdb, fn, private_data);
}
- if (tdb_transaction_lock(tdb, F_WRLCK)) {
+ lock_flags = TDB_LOCK_WAIT;
+
+ if (tdb->allrecord_lock.count != 0) {
+ /*
+ * This avoids a deadlock between tdb_lockall() and
+ * tdb_traverse(). See
+ * https://bugzilla.samba.org/show_bug.cgi?id=11381
+ */
+ lock_flags = TDB_LOCK_NOWAIT;
+ }
+
+ if (tdb_transaction_lock(tdb, F_WRLCK, lock_flags)) {
return -1;
}
ret = tdb_traverse_internal(tdb, fn, private_data, &tl);
tdb->traverse_write--;
- tdb_transaction_unlock(tdb);
+ tdb_transaction_unlock(tdb, F_WRLCK);
return ret;
}
/* find the first entry in the database and return its key */
-TDB_DATA tdb_firstkey(struct tdb_context *tdb)
+_PUBLIC_ TDB_DATA tdb_firstkey(struct tdb_context *tdb)
{
TDB_DATA key;
- struct list_struct rec;
+ 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.hash = 0;
+ tdb->travlocks.off = tdb->travlocks.list = 0;
tdb->travlocks.lock_rw = F_RDLCK;
/* Grab first record: locks chain and returned record. */
tdb_trace_retrec(tdb, "tdb_firstkey", key);
/* Unlock the hash chain of the record we just read. */
- if (tdb_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0)
+ 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)
+_PUBLIC_ TDB_DATA tdb_nextkey(struct tdb_context *tdb, TDB_DATA oldkey)
{
- uint32_t oldhash;
+ uint32_t oldlist;
TDB_DATA key = tdb_null;
- struct list_struct rec;
+ struct tdb_record rec;
unsigned char *k = NULL;
tdb_off_t off;
/* 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))
+ if (tdb_lock(tdb,tdb->travlocks.list,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),
SAFE_FREE(k);
return tdb_null;
}
- if (tdb_unlock(tdb, tdb->travlocks.hash, tdb->travlocks.lock_rw) != 0) {
+ if (tdb_unlock(tdb, tdb->travlocks.list, tdb->travlocks.lock_rw) != 0) {
SAFE_FREE(k);
return tdb_null;
}
tdb_trace_1rec_retrec(tdb, "tdb_nextkey", oldkey, tdb_null);
return tdb_null;
}
- tdb->travlocks.hash = BUCKET(rec.full_hash);
+ tdb->travlocks.list = 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;
+ oldlist = tdb->travlocks.list;
/* Grab next record: locks chain and returned record,
unlocks old record */
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)
+ if (tdb_unlock(tdb, tdb->travlocks.list, 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)
+ if (tdb_unlock(tdb, oldlist, tdb->travlocks.lock_rw) != 0)
TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_nextkey: WARNING tdb_unlock failed!\n"));
tdb_trace_1rec_retrec(tdb, "tdb_nextkey", oldkey, key);
return key;
}
+_PUBLIC_ int tdb_traverse_chain(struct tdb_context *tdb,
+ unsigned chain,
+ tdb_traverse_func fn,
+ void *private_data)
+{
+ tdb_off_t rec_ptr;
+ struct tdb_chainwalk_ctx chainwalk;
+ int count = 0;
+ int ret;
+
+ if (chain >= tdb->hash_size) {
+ tdb->ecode = TDB_ERR_EINVAL;
+ return -1;
+ }
+
+ if (tdb->traverse_read != 0) {
+ tdb->ecode = TDB_ERR_LOCK;
+ return -1;
+ }
+
+ ret = tdb_lock(tdb, chain, F_RDLCK);
+ if (ret == -1) {
+ return -1;
+ }
+
+ tdb->traverse_read += 1;
+
+ ret = tdb_ofs_read(tdb, TDB_HASH_TOP(chain), &rec_ptr);
+ if (ret == -1) {
+ goto fail;
+ }
+
+ tdb_chainwalk_init(&chainwalk, rec_ptr);
+
+ while (rec_ptr != 0) {
+ struct tdb_record rec;
+ bool ok;
+
+ ret = tdb_rec_read(tdb, rec_ptr, &rec);
+ if (ret == -1) {
+ goto fail;
+ }
+
+ if (!TDB_DEAD(&rec)) {
+ /* no overflow checks, tdb_rec_read checked it */
+ tdb_off_t key_ofs = rec_ptr + sizeof(rec);
+ size_t full_len = rec.key_len + rec.data_len;
+ uint8_t *buf = NULL;
+
+ TDB_DATA key = { .dsize = rec.key_len };
+ TDB_DATA data = { .dsize = rec.data_len };
+
+ if ((tdb->transaction == NULL) &&
+ (tdb->map_ptr != NULL)) {
+ ret = tdb_oob(tdb, key_ofs, full_len, 0);
+ if (ret == -1) {
+ goto fail;
+ }
+ key.dptr = (uint8_t *)tdb->map_ptr + key_ofs;
+ } else {
+ buf = tdb_alloc_read(tdb, key_ofs, full_len);
+ if (buf == NULL) {
+ goto fail;
+ }
+ key.dptr = buf;
+ }
+ data.dptr = key.dptr + key.dsize;
+
+ ret = fn(tdb, key, data, private_data);
+ free(buf);
+
+ count += 1;
+
+ if (ret != 0) {
+ break;
+ }
+ }
+
+ rec_ptr = rec.next;
+
+ ok = tdb_chainwalk_check(tdb, &chainwalk, rec_ptr);
+ if (!ok) {
+ goto fail;
+ }
+ }
+ tdb->traverse_read -= 1;
+ tdb_unlock(tdb, chain, F_RDLCK);
+ return count;
+
+fail:
+ tdb->traverse_read -= 1;
+ tdb_unlock(tdb, chain, F_RDLCK);
+ return -1;
+}
+
+_PUBLIC_ int tdb_traverse_key_chain(struct tdb_context *tdb,
+ TDB_DATA key,
+ tdb_traverse_func fn,
+ void *private_data)
+{
+ uint32_t hash, chain;
+ int ret;
+
+ hash = tdb->hash_fn(&key);
+ chain = BUCKET(hash);
+ ret = tdb_traverse_chain(tdb, chain, fn, private_data);
+
+ return ret;
+}
git.samba.org / samba.git / blobdiff