dbwrap: dbwrap_ntdb.c

This is a dbwrap backend for ntdb.  It's a fairly straight conversion from
the tdb version.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

3 files changed, 734 insertions, 10 deletions

diff --git a/lib/dbwrap/dbwrap_ntdb.c b/lib/dbwrap/dbwrap_ntdb.c
new file mode 100644
index 0000000000..5be7b842e2
--- /dev/null
+++ b/lib/dbwrap/dbwrap_ntdb.c
@@ -0,0 +1,689 @@
+/*
+   Unix SMB/CIFS implementation.
+   Database interface wrapper around ntdb
+   Copyright (C) Volker Lendecke 2005-2007
+   Copyright (C) Rusty Russell 2012
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "dbwrap/dbwrap.h"
+#include "dbwrap/dbwrap_private.h"
+#include "dbwrap/dbwrap_ntdb.h"
+#include "system/filesys.h"
+#include "lib/util/util_ntdb.h"
+#include "ccan/str/str.h"
+
+struct db_ntdb_ctx {
+	struct ntdb_context *ntdb;
+
+	struct {
+		dev_t dev;
+		ino_t ino;
+	} id;
+};
+
+static int tdb_store_flag_to_ntdb(int tdb_flag)
+{
+	switch (tdb_flag) {
+	/* In fact, any value defaults to TDB_REPLACE in tdb! */
+	case 0:
+	case TDB_REPLACE:
+		return NTDB_REPLACE;
+	case TDB_INSERT:
+		return NTDB_INSERT;
+	case TDB_MODIFY:
+		return NTDB_MODIFY;
+	default:
+		smb_panic("unknown tdb_flag");
+	}
+}
+
+static NTSTATUS db_ntdb_store(struct db_record *rec, NTDB_DATA data, int flag)
+{
+	int ntdb_flag = tdb_store_flag_to_ntdb(flag);
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(rec->private_data,
+							struct db_ntdb_ctx);
+
+	/*
+	 * This has a bug: We need to replace rec->value for correct
+	 * operation, but right now brlock and locking don't use the value
+	 * anymore after it was stored.
+	 */
+
+	if (ntdb_store(ctx->ntdb, rec->key, data, ntdb_flag) == NTDB_SUCCESS) {
+		return NT_STATUS_OK;
+	}
+	return NT_STATUS_UNSUCCESSFUL;
+}
+
+static NTSTATUS db_ntdb_delete(struct db_record *rec)
+{
+	enum NTDB_ERROR err;
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(rec->private_data,
+						       struct db_ntdb_ctx);
+
+	err = ntdb_delete(ctx->ntdb, rec->key);
+	if (err == NTDB_SUCCESS) {
+		return NT_STATUS_OK;
+	}
+
+	if (err == NTDB_ERR_NOEXIST) {
+		return NT_STATUS_NOT_FOUND;
+	}
+
+	return NT_STATUS_UNSUCCESSFUL;
+}
+
+static void db_ntdb_log_key(const char *prefix, NTDB_DATA key)
+{
+	size_t len;
+	char *keystr;
+
+	if (DEBUGLEVEL < 10) {
+		return;
+	}
+	len = key.dsize;
+	if (DEBUGLEVEL == 10) {
+		/*
+		 * Only fully spam at debuglevel > 10
+		 */
+		len = MIN(10, key.dsize);
+	}
+	keystr = hex_encode_talloc(talloc_tos(), (unsigned char *)(key.dptr),
+				   len);
+	DEBUG(10, ("%s key %s\n", prefix, keystr));
+	TALLOC_FREE(keystr);
+}
+
+static int db_ntdb_record_destr(struct db_record* data)
+{
+	struct db_ntdb_ctx *ctx =
+		talloc_get_type_abort(data->private_data, struct db_ntdb_ctx);
+
+	db_ntdb_log_key("Unlocking", data->key);
+	ntdb_chainunlock(ctx->ntdb, data->key);
+	return 0;
+}
+
+struct ntdb_fetch_locked_state {
+	TALLOC_CTX *mem_ctx;
+	struct db_record *result;
+};
+
+static enum NTDB_ERROR db_ntdb_fetchlock_parse(NTDB_DATA key, NTDB_DATA data,
+					       struct ntdb_fetch_locked_state *state)
+{
+	struct db_record *result;
+
+	result = (struct db_record *)talloc_size(
+		state->mem_ctx,
+		sizeof(struct db_record) + key.dsize + data.dsize);
+
+	if (result == NULL) {
+		return NTDB_ERR_OOM;
+	}
+	state->result = result;
+
+	result->key.dsize = key.dsize;
+	result->key.dptr = ((uint8_t *)result) + sizeof(struct db_record);
+	memcpy(result->key.dptr, key.dptr, key.dsize);
+
+	result->value.dsize = data.dsize;
+
+	if (data.dsize > 0) {
+		result->value.dptr = result->key.dptr+key.dsize;
+		memcpy(result->value.dptr, data.dptr, data.dsize);
+	}
+	else {
+		result->value.dptr = NULL;
+	}
+
+	return NTDB_SUCCESS;
+}
+
+static struct db_record *db_ntdb_fetch_locked_internal(
+	struct db_context *db, TALLOC_CTX *mem_ctx, NTDB_DATA key)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+							struct db_ntdb_ctx);
+	struct ntdb_fetch_locked_state state;
+	enum NTDB_ERROR err;
+	NTDB_DATA null = { NULL, 0 };
+
+	state.mem_ctx = mem_ctx;
+	state.result = NULL;
+
+	err = ntdb_parse_record(ctx->ntdb, key, db_ntdb_fetchlock_parse,
+				&state);
+	if (err != NTDB_SUCCESS && err != NTDB_ERR_NOEXIST) {
+		ntdb_chainunlock(ctx->ntdb, key);
+		return NULL;
+	}
+
+	if (state.result == NULL) {
+		db_ntdb_fetchlock_parse(key, null, &state);
+	}
+
+	if (state.result == NULL) {
+		ntdb_chainunlock(ctx->ntdb, key);
+		return NULL;
+	}
+
+	talloc_set_destructor(state.result, db_ntdb_record_destr);
+
+	state.result->private_data = talloc_reference(state.result, ctx);
+	state.result->store = db_ntdb_store;
+	state.result->delete_rec = db_ntdb_delete;
+
+	DEBUG(10, ("Allocated locked data 0x%p\n", state.result));
+
+	return state.result;
+}
+
+static struct db_record *db_ntdb_fetch_locked(
+	struct db_context *db, TALLOC_CTX *mem_ctx, NTDB_DATA key)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+						       struct db_ntdb_ctx);
+
+	db_ntdb_log_key("Locking", key);
+	if (ntdb_chainlock(ctx->ntdb, key) != 0) {
+		DEBUG(3, ("ntdb_chainlock failed\n"));
+		return NULL;
+	}
+	return db_ntdb_fetch_locked_internal(db, mem_ctx, key);
+}
+
+/* Proxy which sets waitflag to false so we never block. */
+static int lock_nonblock(int fd, int rw, off_t off, off_t len, bool waitflag,
+			 void *_orig)
+{
+	struct ntdb_attribute_flock *orig = _orig;
+
+	return orig->lock(fd, rw, off, len, false, orig->data);
+}
+
+static enum NTDB_ERROR enable_nonblock(struct ntdb_context *ntdb,
+				       union ntdb_attribute *orig)
+{
+	union ntdb_attribute locking;
+	enum NTDB_ERROR ecode;
+
+	orig->base.attr = NTDB_ATTRIBUTE_FLOCK;
+	ecode = ntdb_get_attribute(ntdb, orig);
+	if (ecode != NTDB_SUCCESS) {
+		return ecode;
+	}
+
+	/* Replace locking function with our own. */
+	locking = *orig;
+	locking.flock.data = orig;
+	locking.flock.lock = lock_nonblock;
+
+	return ntdb_set_attribute(ntdb, &locking);
+}
+
+static void disable_nonblock(struct ntdb_context *ntdb)
+{
+	ntdb_unset_attribute(ntdb, NTDB_ATTRIBUTE_FLOCK);
+}
+
+static enum NTDB_ERROR ntdb_chainlock_nonblock(struct ntdb_context *ntdb,
+					       NTDB_DATA key)
+{
+	union ntdb_attribute orig;
+	enum NTDB_ERROR ecode;
+
+	ecode = enable_nonblock(ntdb, &orig);
+	if (!ecode) {
+		ecode = ntdb_chainlock(ntdb, key);
+		disable_nonblock(ntdb);
+	}
+	return ecode;
+}
+
+static struct db_record *db_ntdb_try_fetch_locked(
+	struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+						       struct db_ntdb_ctx);
+
+	db_ntdb_log_key("Trying to lock", key);
+	if (ntdb_chainlock_nonblock(ctx->ntdb, key) != 0) {
+		DEBUG(3, ("ntdb_chainlock_nonblock failed\n"));
+		return NULL;
+	}
+	return db_ntdb_fetch_locked_internal(db, mem_ctx, key);
+}
+
+static struct flock flock_struct;
+
+/* Return a value which is none of v1, v2 or v3. */
+static inline short int invalid_value(short int v1, short int v2, short int v3)
+{
+	short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
+	while (try == v1 || try == v2 || try == v3)
+		try++;
+	return try;
+}
+
+/* We invalidate in as many ways as we can, so the OS rejects it */
+static void invalidate_flock_struct(int signum)
+{
+	flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
+	flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
+	flock_struct.l_start = -1;
+	/* A large negative. */
+	flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
+}
+
+static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
+			void *_timeout)
+{
+	int ret, saved_errno;
+	unsigned int timeout = *(unsigned int *)_timeout;
+
+	flock_struct.l_type = rw;
+	flock_struct.l_whence = SEEK_SET;
+	flock_struct.l_start = off;
+	flock_struct.l_len = len;
+
+	CatchSignal(SIGALRM, invalidate_flock_struct);
+	alarm(timeout);
+
+	for (;;) {
+		if (waitflag)
+			ret = fcntl(fd, F_SETLKW, &flock_struct);
+		else
+			ret = fcntl(fd, F_SETLK, &flock_struct);
+
+		if (ret == 0)
+			break;
+
+		/* Not signalled?  Something else went wrong. */
+		if (flock_struct.l_len == len) {
+			if (errno == EAGAIN || errno == EINTR)
+				continue;
+			saved_errno = errno;
+			break;
+		} else {
+			saved_errno = EINTR;
+			break;
+		}
+	}
+
+	alarm(0);
+	errno = saved_errno;
+	return ret;
+}
+
+static int ntdb_chainlock_timeout(struct ntdb_context *ntdb,
+				  NTDB_DATA key,
+				  unsigned int timeout)
+{
+	union ntdb_attribute locking;
+	enum NTDB_ERROR ecode;
+
+	locking.base.attr = NTDB_ATTRIBUTE_FLOCK;
+	ecode = ntdb_get_attribute(ntdb, &locking);
+	if (ecode != NTDB_SUCCESS) {
+		return -1;
+	}
+
+	/* Replace locking function with our own. */
+	locking.flock.data = &timeout;
+	locking.flock.lock = timeout_lock;
+
+	ecode = ntdb_set_attribute(ntdb, &locking);
+	if (ecode != NTDB_SUCCESS) {
+		return -1;
+	}
+
+	ecode = ntdb_chainlock(ntdb, key);
+
+	ntdb_unset_attribute(ntdb, NTDB_ATTRIBUTE_FLOCK);
+	return ecode == NTDB_SUCCESS ? 0 : -1;
+}
+
+static struct db_record *db_ntdb_fetch_locked_timeout(
+	struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key,
+	unsigned int timeout)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(db->private_data,
+						       struct db_ntdb_ctx);
+
+	db_ntdb_log_key("Trying to lock", key);
+	if (ntdb_chainlock_timeout(ctx->ntdb, key, timeout) != 0) {
+		DEBUG(3, ("ntdb_chainlock_timeout failed\n"));
+		return NULL;
+	}
+	return db_ntdb_fetch_locked_internal(db, mem_ctx, key);
+}
+
+
+static int db_ntdb_exists(struct db_context *db, TDB_DATA key)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ntdb_ctx);
+	return ntdb_exists(ctx->ntdb, key);
+}
+
+static int db_ntdb_wipe(struct db_context *db)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ntdb_ctx);
+	if (ntdb_wipe_all(ctx->ntdb) != NTDB_SUCCESS) {
+		return -1;
+	}
+	return 0;
+}
+
+static int db_ntdb_check(struct db_context *db)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ntdb_ctx);
+	if (ntdb_check(ctx->ntdb, NULL, NULL) != NTDB_SUCCESS) {
+		return -1;
+	}
+	return 0;
+}
+
+struct db_ntdb_parse_state {
+	void (*parser)(TDB_DATA key, TDB_DATA data,
+		       void *private_data);
+	void *private_data;
+};
+
+/*
+ * ntdb_parse_record expects a parser returning enum NTDB_ERROR,
+ * mixing up ntdb and parser errors. Wrap around that by always
+ * returning NTDB_SUCCESS and have dbwrap_parse_record expect a parser
+ * returning void.
+ */
+
+static enum NTDB_ERROR db_ntdb_parser(NTDB_DATA key, NTDB_DATA data,
+				      struct db_ntdb_parse_state *state)
+{
+	state->parser(key, data, state->private_data);
+	return TDB_SUCCESS;
+}
+
+static NTSTATUS db_ntdb_parse(struct db_context *db, TDB_DATA key,
+			      void (*parser)(TDB_DATA key, TDB_DATA data,
+					     void *private_data),
+			      void *private_data)
+{
+	struct db_ntdb_ctx *ctx = talloc_get_type_abort(
+		db->private_data, struct db_ntdb_ctx);
+	struct db_ntdb_parse_state state;
+	enum NTDB_ERROR err;
+
+	state.parser = parser;
+	state.private_data = private_data;
+
+	err = ntdb_parse_record(ctx->ntdb, key, db_ntdb_parser, &state);
+	return map_nt_error_from_ntdb(err);
+}
+
+struct db_ntdb_traverse_ctx {
+	struct db_context *db;
+	int (*f)(struct db_record *rec, void *private_data);
+	void *private_data;
+};
+
+static int db_ntdb_traverse_func(struct ntdb_context *ntdb,
+				 NTDB_DATA kbuf, NTDB_DATA dbuf,
+				 struct db_ntdb_traverse_ctx *ctx)
+{
+	struct db_record rec;
+
+	rec.key = kbuf;
+	rec.value = dbuf;
+	rec.store = db_ntdb_store;
+	rec.delete_rec = db_ntdb_delete;
+	rec.private_data = ctx->db->private_data;
+	rec.db = ctx->db;
+
+	return ctx->f(&rec, ctx->private_data);
+}
+
+static int db_ntdb_traverse(struct db_context *db,
+			    int (*f)(struct db_record *rec, void *private_data),
+			    void *private_data)
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	struct db_ntdb_traverse_ctx ctx;
+	int64_t ret;
+
+	ctx.db = db;
+	ctx.f = f;
+	ctx.private_data = private_data;
+	ret = ntdb_traverse(db_ctx->ntdb, db_ntdb_traverse_func, &ctx);
+
+	if (ret < 0) {
+		return -1;
+	}
+
+	/* Make sure we don't truncate! */
+	if ((int)ret != ret) {
+		ret = INT_MAX;
+	}
+	return ret;
+}
+
+static NTSTATUS db_ntdb_store_deny(struct db_record *rec, NTDB_DATA data, int flag)
+{
+	return NT_STATUS_MEDIA_WRITE_PROTECTED;
+}
+
+static NTSTATUS db_ntdb_delete_deny(struct db_record *rec)
+{
+	return NT_STATUS_MEDIA_WRITE_PROTECTED;
+}
+
+static int db_ntdb_traverse_read_func(struct ntdb_context *ntdb,
+				      NTDB_DATA kbuf, NTDB_DATA dbuf,
+				      struct db_ntdb_traverse_ctx *ctx)
+{
+	struct db_record rec;
+
+	rec.key = kbuf;
+	rec.value = dbuf;
+	rec.store = db_ntdb_store_deny;
+	rec.delete_rec = db_ntdb_delete_deny;
+	rec.private_data = ctx->db->private_data;
+	rec.db = ctx->db;
+
+	return ctx->f(&rec, ctx->private_data);
+}
+
+static int db_ntdb_traverse_read(struct db_context *db,
+				 int (*f)(struct db_record *rec,
+					  void *private_data),
+				 void *private_data)
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	struct db_ntdb_traverse_ctx ctx;
+	int64_t ret;
+
+	ctx.db = db;
+	ctx.f = f;
+	ctx.private_data = private_data;
+
+	/* This is a bit of paranoia to check that f() isn't altering
+	 * database. */
+	if (ntdb_get_flags(db_ctx->ntdb) & NTDB_RDONLY) {
+		ret = ntdb_traverse(db_ctx->ntdb, db_ntdb_traverse_read_func,
+				    &ctx);
+	} else {
+		ntdb_add_flag(db_ctx->ntdb, NTDB_RDONLY);
+		ret = ntdb_traverse(db_ctx->ntdb, db_ntdb_traverse_read_func,
+				    &ctx);
+		ntdb_remove_flag(db_ctx->ntdb, NTDB_RDONLY);
+	}
+
+	if (ret < 0) {
+		return -1;
+	}
+
+	/* Make sure we don't truncate! */
+	if ((int)ret != ret) {
+		ret = INT_MAX;
+	}
+	return ret;
+}
+
+static int db_ntdb_get_seqnum(struct db_context *db)
+
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	return ntdb_get_seqnum(db_ctx->ntdb);
+}
+
+static int db_ntdb_transaction_start(struct db_context *db)
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	return ntdb_transaction_start(db_ctx->ntdb) == NTDB_SUCCESS ? 0 : -1;
+}
+
+static NTSTATUS db_ntdb_transaction_start_nonblock(struct db_context *db)
+{
+	union ntdb_attribute orig;
+	enum NTDB_ERROR ecode;
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+
+	ecode = enable_nonblock(db_ctx->ntdb, &orig);
+	if (!ecode) {
+		ecode = ntdb_transaction_start(db_ctx->ntdb);
+		disable_nonblock(db_ctx->ntdb);
+	}
+	return map_nt_error_from_ntdb(ecode);
+}
+
+static int db_ntdb_transaction_commit(struct db_context *db)
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	return ntdb_transaction_commit(db_ctx->ntdb) == NTDB_SUCCESS ? 0 : -1;
+}
+
+static int db_ntdb_transaction_cancel(struct db_context *db)
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	ntdb_transaction_cancel(db_ctx->ntdb);
+	return 0;
+}
+
+static void db_ntdb_id(struct db_context *db, const uint8_t **id, size_t *idlen)
+{
+	struct db_ntdb_ctx *db_ctx =
+		talloc_get_type_abort(db->private_data, struct db_ntdb_ctx);
+	*id = (uint8_t *)&db_ctx->id;
+	*idlen = sizeof(db_ctx->id);
+}
+
+/* Don't ask this to open a .tdb file: dbwrap_local_open will catch that. */
+struct db_context *db_open_ntdb(TALLOC_CTX *mem_ctx,
+				struct loadparm_context *lp_ctx,
+				const char *ntdbname,
+				int hash_size, int ntdb_flags,
+				int open_flags, mode_t mode,
+				enum dbwrap_lock_order lock_order)
+{
+	struct db_context *result = NULL;
+	struct db_ntdb_ctx *db_ntdb;
+	struct stat st;
+	union ntdb_attribute hattr;
+
+	if ((ntdb_flags & NTDB_INTERNAL) && !ntdbname) {
+		ntdbname = "unnamed";
+	}
+
+	/* Extra paranoia. */
+	if (strends(ntdbname, ".tdb")) {
+		DEBUG(0, ("can't try to open %s with ntdb!", ntdbname));
+		return NULL;
+	}
+
+	/* We only use this if hsize is non-zero. */
+	hattr.base.attr = NTDB_ATTRIBUTE_HASHSIZE;
+	hattr.base.next = NULL;
+	hattr.hashsize.size = hash_size;
+
+	result = talloc_zero(mem_ctx, struct db_context);
+	if (result == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		goto fail;
+	}
+
+	result->private_data = db_ntdb = talloc(result, struct db_ntdb_ctx);
+	if (db_ntdb == NULL) {
+		DEBUG(0, ("talloc failed\n"));
+		goto fail;
+	}
+	result->lock_order = lock_order;
+
+	db_ntdb->ntdb = ntdb_new(db_ntdb, ntdbname, ntdb_flags,
+				 open_flags, mode,
+				 hash_size ? &hattr : NULL, lp_ctx);
+	if (db_ntdb->ntdb == NULL) {
+		DEBUG(3, ("Could not open ntdb %s: %s\n",
+			  ntdbname, strerror(errno)));
+		goto fail;
+	}
+
+	ZERO_STRUCT(db_ntdb->id);
+
+	if (fstat(ntdb_fd(db_ntdb->ntdb), &st) == -1) {
+		DEBUG(3, ("fstat failed: %s\n", strerror(errno)));
+		goto fail;
+	}
+	db_ntdb->id.dev = st.st_dev;
+	db_ntdb->id.ino = st.st_ino;
+
+	result->fetch_locked = db_ntdb_fetch_locked;
+	result->fetch_locked_timeout = db_ntdb_fetch_locked_timeout;
+	result->try_fetch_locked = db_ntdb_try_fetch_locked;
+	result->traverse = db_ntdb_traverse;
+	result->traverse_read = db_ntdb_traverse_read;
+	result->parse_record = db_ntdb_parse;
+	result->get_seqnum = db_ntdb_get_seqnum;
+	result->persistent = ((ntdb_flags & NTDB_CLEAR_IF_FIRST) == 0);
+	result->transaction_start = db_ntdb_transaction_start;
+	result->transaction_start_nonblock = db_ntdb_transaction_start_nonblock;
+	result->transaction_commit = db_ntdb_transaction_commit;
+	result->transaction_cancel = db_ntdb_transaction_cancel;
+	result->exists = db_ntdb_exists;
+	result->wipe = db_ntdb_wipe;
+	result->id = db_ntdb_id;
+	result->check = db_ntdb_check;
+	result->stored_callback = NULL;
+	result->name = ntdb_name(db_ntdb->ntdb);
+	result->hash_size = hash_size;
+	return result;
+
+ fail:
+	if (result != NULL) {
+		TALLOC_FREE(result);
+	}
+	return NULL;
+}
diff --git a/lib/dbwrap/dbwrap_ntdb.h b/lib/dbwrap/dbwrap_ntdb.h
new file mode 100644
index 0000000000..b00a5670a2
--- /dev/null
+++ b/lib/dbwrap/dbwrap_ntdb.h
@@ -0,0 +1,35 @@
+/*
+   Unix SMB/CIFS implementation.
+   Database interface wrapper around ntdb
+   Copyright (C) Volker Lendecke 2005-2007
+   Copyright (C) Rusty Russell 2012
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef __DBWRAP_NTDB_H__
+#define __DBWRAP_NTDB_H__
+
+#include <talloc.h>
+
+struct db_context;
+
+struct db_context *db_open_ntdb(TALLOC_CTX *mem_ctx,
+				struct loadparm_context *lp_ctx,
+				const char *name,
+				int hash_size, int ntdb_flags,
+				int open_flags, mode_t mode,
+				enum dbwrap_lock_order lock_order);
+
+#endif /* __DBWRAP_NTDB_H__ */
diff --git a/lib/dbwrap/wscript_build b/lib/dbwrap/wscript_build
index 3b247b3b5b..83572cbb8f 100644
--- a/lib/dbwrap/wscript_build
+++ b/lib/dbwrap/wscript_build
@@ -1,12 +1,12 @@
+SRC = '''dbwrap.c dbwrap_util.c dbwrap_rbt.c dbwrap_cache.c dbwrap_tdb.c
+         dbwrap_local_open.c'''
+DEPS= '''samba-util util_tdb errors tdb tdb-wrap'''
+
+if not bld.env.disable_ntdb:
+   SRC += " dbwrap_ntdb.c"
+   DEPS += " util_ntdb"
+
 bld.SAMBA_LIBRARY('dbwrap',
-                  source='''
-                  dbwrap.c
-                  dbwrap_util.c
-                  dbwrap_rbt.c
-                  dbwrap_cache.c
-                  dbwrap_tdb.c
-                  dbwrap_local_open.c
-                  ''',
-                  deps='samba-util util_tdb errors tdb tdb-wrap',
+                  source=SRC,
+                  deps=DEPS,
                   private_library=True)
-