/* 
   Unix SMB/CIFS implementation.
   Database interface wrapper around tdb
   Copyright (C) Volker Lendecke 2005-2007
   
   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"

struct db_tdb_ctx {
	struct tdb_wrap *wtdb;
};

static NTSTATUS db_tdb_store(struct db_record *rec, TDB_DATA data, int flag);
static NTSTATUS db_tdb_delete(struct db_record *rec);

static int db_tdb_record_destr(struct db_record* data)
{
	struct db_tdb_ctx *ctx =
		talloc_get_type_abort(data->private_data, struct db_tdb_ctx);

	DEBUG(10, (DEBUGLEVEL > 10
		   ? "Unlocking key %s\n" : "Unlocking key %.20s\n",
		   hex_encode(data, (unsigned char *)data->key.dptr,
			      data->key.dsize)));

	if (tdb_chainunlock(ctx->wtdb->tdb, data->key) != 0) {
		DEBUG(0, ("tdb_chainunlock failed\n"));
		return -1;
	}
	return 0;
}

struct tdb_fetch_locked_state {
	TALLOC_CTX *mem_ctx;
	struct db_record *result;
};

static int db_tdb_fetchlock_parse(TDB_DATA key, TDB_DATA data,
				  void *private_data)
{
	struct tdb_fetch_locked_state *state =
		(struct tdb_fetch_locked_state *)private_data;

	state->result = (struct db_record *)talloc_size(
		state->mem_ctx,
		sizeof(struct db_record) + key.dsize + data.dsize);

	if (state->result == NULL) {
		return 0;
	}

	state->result->key.dsize = key.dsize;
	state->result->key.dptr = ((uint8 *)state->result)
		+ sizeof(struct db_record);
	memcpy(state->result->key.dptr, key.dptr, key.dsize);

	state->result->value.dsize = data.dsize;

	if (data.dsize > 0) {
		state->result->value.dptr = state->result->key.dptr+key.dsize;
		memcpy(state->result->value.dptr, data.dptr, data.dsize);
	}
	else {
		state->result->value.dptr = NULL;
	}

	return 0;
}

static struct db_record *db_tdb_fetch_locked(struct db_context *db,
				     TALLOC_CTX *mem_ctx, TDB_DATA key)
{
	struct db_tdb_ctx *ctx = talloc_get_type_abort(db->private_data,
						       struct db_tdb_ctx);
	struct tdb_fetch_locked_state state;
	int res;

	if (DEBUGLEVEL >= 10) {
		char *keystr = hex_encode(NULL, key.dptr, key.dsize);
		DEBUG(10, (DEBUGLEVEL > 10
			   ? "Locking key %s\n" : "Locking key %.20s\n",
			   keystr));
		TALLOC_FREE(keystr);
	}

	if (tdb_chainlock(ctx->wtdb->tdb, key) != 0) {
		DEBUG(3, ("tdb_chainlock failed\n"));
		return NULL;
	}

	state.mem_ctx = mem_ctx;
	state.result = NULL;

	res = tdb_parse_record(ctx->wtdb->tdb, key, db_tdb_fetchlock_parse,
			       &state);

	if (state.result == NULL) {
		db_tdb_fetchlock_parse(key, tdb_null, &state);
	}

	if (state.result == NULL) {
		tdb_chainunlock(ctx->wtdb->tdb, key);
		return NULL;
	}

	talloc_set_destructor(state.result, db_tdb_record_destr);

	state.result->private_data = talloc_reference(state.result, ctx);
	state.result->store = db_tdb_store;
	state.result->delete_rec = db_tdb_delete;

	DEBUG(10, ("Allocated locked data 0x%p\n", state.result));

	return state.result;
}

struct tdb_fetch_state {
	TALLOC_CTX *mem_ctx;
	int result;
	TDB_DATA data;
};

static int db_tdb_fetch_parse(TDB_DATA key, TDB_DATA data,
			      void *private_data)
{
	struct tdb_fetch_state *state =
		(struct tdb_fetch_state *)private_data;

	state->data.dptr = (uint8 *)talloc_memdup(state->mem_ctx, data.dptr,
						  data.dsize);
	if (state->data.dptr == NULL) {
		state->result = -1;
		return 0;
	}

	state->data.dsize = data.dsize;
	return 0;
}

static int db_tdb_fetch(struct db_context *db, TALLOC_CTX *mem_ctx,
			TDB_DATA key, TDB_DATA *pdata)
{
	struct db_tdb_ctx *ctx = talloc_get_type_abort(
		db->private_data, struct db_tdb_ctx);

	struct tdb_fetch_state state;

	state.mem_ctx = mem_ctx;
	state.result = 0;
	state.data.dptr = NULL;
	state.data.dsize = 0;

	tdb_parse_record(ctx->wtdb->tdb, key, db_tdb_fetch_parse, &state);

	if (state.result == -1) {
		return -1;
	}

	*pdata = state.data;
	return 0;
}

static NTSTATUS db_tdb_store(struct db_record *rec, TDB_DATA data, int flag)
{
	struct db_tdb_ctx *ctx = talloc_get_type_abort(rec->private_data,
						       struct db_tdb_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.
	 */

	return (tdb_store(ctx->wtdb->tdb, rec->key, data, flag) == 0) ?
		NT_STATUS_OK : NT_STATUS_UNSUCCESSFUL;
}

static NTSTATUS db_tdb_delete(struct db_record *rec)
{
	struct db_tdb_ctx *ctx = talloc_get_type_abort(rec->private_data,
						       struct db_tdb_ctx);
	int res;
	
	res = tdb_delete(ctx->wtdb->tdb, rec->key);

	if (res == 0) {
		return NT_STATUS_OK;
	}

	return map_nt_error_from_tdb(tdb_error(ctx->wtdb->tdb));
}

struct db_tdb_traverse_ctx {
	struct db_context *db;
	int (*f)(struct db_record *rec, void *private_data);
	void *private_data;
};

static int db_tdb_traverse_func(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf,
				void *private_data)
{
	struct db_tdb_traverse_ctx *ctx =
		(struct db_tdb_traverse_ctx *)private_data;
	struct db_record rec;

	rec.key = kbuf;
	rec.value = dbuf;
	rec.store = db_tdb_store;
	rec.delete_rec = db_tdb_delete;
	rec.private_data = ctx->db->private_data;

	return ctx->f(&rec, ctx->private_data);
}

static int db_tdb_traverse(struct db_context *db,
			   int (*f)(struct db_record *rec, void *private_data),
			   void *private_data)
{
	struct db_tdb_ctx *db_ctx =
		talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
	struct db_tdb_traverse_ctx ctx;

	ctx.db = db;
	ctx.f = f;
	ctx.private_data = private_data;
	return tdb_traverse(db_ctx->wtdb->tdb, db_tdb_traverse_func, &ctx);
}

static NTSTATUS db_tdb_store_deny(struct db_record *rec, TDB_DATA data, int flag)
{
	return NT_STATUS_MEDIA_WRITE_PROTECTED;
}

static NTSTATUS db_tdb_delete_deny(struct db_record *rec)
{
	return NT_STATUS_MEDIA_WRITE_PROTECTED;
}

static int db_tdb_traverse_read_func(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf,
				void *private_data)
{
	struct db_tdb_traverse_ctx *ctx =
		(struct db_tdb_traverse_ctx *)private_data;
	struct db_record rec;

	rec.key = kbuf;
	rec.value = dbuf;
	rec.store = db_tdb_store_deny;
	rec.delete_rec = db_tdb_delete_deny;
	rec.private_data = ctx->db->private_data;

	return ctx->f(&rec, ctx->private_data);
}

static int db_tdb_traverse_read(struct db_context *db,
			   int (*f)(struct db_record *rec, void *private_data),
			   void *private_data)
{
	struct db_tdb_ctx *db_ctx =
		talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
	struct db_tdb_traverse_ctx ctx;

	ctx.db = db;
	ctx.f = f;
	ctx.private_data = private_data;
	return tdb_traverse_read(db_ctx->wtdb->tdb, db_tdb_traverse_read_func, &ctx);
}

static int db_tdb_get_seqnum(struct db_context *db)

{
	struct db_tdb_ctx *db_ctx =
		talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
	return tdb_get_seqnum(db_ctx->wtdb->tdb);
}

struct db_context *db_open_tdb(TALLOC_CTX *mem_ctx,
			       const char *name,
			       int hash_size, int tdb_flags,
			       int open_flags, mode_t mode)
{
	struct db_context *result = NULL;
	struct db_tdb_ctx *db_tdb;

	result = TALLOC_ZERO_P(mem_ctx, struct db_context);
	if (result == NULL) {
		DEBUG(0, ("talloc failed\n"));
		goto fail;
	}

	result->private_data = db_tdb = TALLOC_P(result, struct db_tdb_ctx);
	if (db_tdb == NULL) {
		DEBUG(0, ("talloc failed\n"));
		goto fail;
	}

	db_tdb->wtdb = tdb_wrap_open(db_tdb, name, hash_size, tdb_flags,
				     open_flags, mode);
	if (db_tdb->wtdb == NULL) {
		DEBUG(3, ("Could not open tdb: %s\n", strerror(errno)));
		goto fail;
	}

	result->fetch_locked = db_tdb_fetch_locked;
	result->fetch = db_tdb_fetch;
	result->traverse = db_tdb_traverse;
	result->traverse_read = db_tdb_traverse_read;
	result->get_seqnum = db_tdb_get_seqnum;
	return result;

 fail:
	if (result != NULL) {
		TALLOC_FREE(result);
	}
	return NULL;
}