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/*
Unix SMB/CIFS implementation.
Cache db contents for parse_record based on seqnum
Copyright (C) Volker Lendecke 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 "lib/dbwrap/dbwrap.h"
#include "lib/dbwrap/dbwrap_private.h"
#include "lib/dbwrap/dbwrap_rbt.h"
#include "lib/dbwrap/dbwrap_cache.h"
struct db_cache_ctx {
int seqnum;
struct db_context *backing;
struct db_context *positive;
struct db_context *negative;
};
static bool dbwrap_cache_validate(struct db_cache_ctx *ctx)
{
if (ctx->seqnum == dbwrap_get_seqnum(ctx->backing)) {
return true;
}
TALLOC_FREE(ctx->positive);
ctx->positive = db_open_rbt(ctx);
TALLOC_FREE(ctx->negative);
ctx->negative = db_open_rbt(ctx);
return ((ctx->positive != NULL) && (ctx->negative != NULL));
}
static NTSTATUS dbwrap_cache_parse_record(
struct db_context *db, TDB_DATA key,
void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data),
void *private_data)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
TDB_DATA value;
NTSTATUS status;
if (!dbwrap_cache_validate(ctx)) {
return NT_STATUS_NO_MEMORY;
}
status = dbwrap_parse_record(ctx->positive, key, parser, private_data);
if (NT_STATUS_IS_OK(status)) {
return status;
}
if (dbwrap_exists(ctx->negative, key)) {
return NT_STATUS_NOT_FOUND;
}
status = dbwrap_fetch(ctx->backing, talloc_tos(), key, &value);
if (NT_STATUS_IS_OK(status)) {
dbwrap_store(ctx->positive, key, value, 0);
parser(key, value, private_data);
TALLOC_FREE(value.dptr);
return NT_STATUS_OK;
}
if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
char c = '\0';
value.dptr = (uint8_t *)&c;
value.dsize = sizeof(c);
dbwrap_store(ctx->negative, key, value, 0);
return NT_STATUS_NOT_FOUND;
}
return status;
}
static struct db_record *dbwrap_cache_fetch_locked(
struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
return dbwrap_fetch_locked(ctx->backing, mem_ctx, key);
}
static int dbwrap_cache_traverse(struct db_context *db,
int (*f)(struct db_record *rec,
void *private_data),
void *private_data)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
NTSTATUS status;
int ret;
status = dbwrap_traverse(ctx->backing, f, private_data, &ret);
if (!NT_STATUS_IS_OK(status)) {
return -1;
}
return ret;
}
static int dbwrap_cache_traverse_read(struct db_context *db,
int (*f)(struct db_record *rec,
void *private_data),
void *private_data)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
NTSTATUS status;
int ret;
status = dbwrap_traverse_read(ctx->backing, f, private_data, &ret);
if (!NT_STATUS_IS_OK(status)) {
return -1;
}
return ret;
}
static int dbwrap_cache_get_seqnum(struct db_context *db)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
return dbwrap_get_seqnum(ctx->backing);
}
static int dbwrap_cache_get_flags(struct db_context *db)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
return dbwrap_get_flags(ctx->backing);
}
static int dbwrap_cache_transaction_start(struct db_context *db)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
return dbwrap_transaction_start(ctx->backing);
}
static int dbwrap_cache_transaction_commit(struct db_context *db)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
return dbwrap_transaction_commit(ctx->backing);
}
static int dbwrap_cache_transaction_cancel(struct db_context *db)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
return dbwrap_transaction_cancel(ctx->backing);
}
static int dbwrap_cache_exists(struct db_context *db, TDB_DATA key)
{
struct db_cache_ctx *ctx = talloc_get_type_abort(
db->private_data, struct db_cache_ctx);
if (ctx->positive && dbwrap_exists(ctx->positive, key)) {
return true;
}
if (ctx->negative && dbwrap_exists(ctx->negative, key)) {
return false;
}
return dbwrap_exists(ctx->backing, key);
}
struct db_context *db_open_cache(TALLOC_CTX *mem_ctx,
struct db_context *backing)
{
struct db_context *db;
struct db_cache_ctx *ctx;
db = talloc(mem_ctx, struct db_context);
if (db == NULL) {
return NULL;
}
ctx = talloc_zero(db, struct db_cache_ctx);
if (ctx == NULL) {
TALLOC_FREE(db);
return NULL;
}
ctx->seqnum = -1;
ctx->backing = talloc_move(ctx, &backing);
db->private_data = ctx;
if (!dbwrap_cache_validate(ctx)) {
TALLOC_FREE(db);
return NULL;
}
db->fetch_locked = dbwrap_cache_fetch_locked;
db->try_fetch_locked = NULL;
db->traverse = dbwrap_cache_traverse;
db->traverse_read = dbwrap_cache_traverse_read;
db->get_seqnum = dbwrap_cache_get_seqnum;
db->get_flags = dbwrap_cache_get_flags;
db->transaction_start = dbwrap_cache_transaction_start;
db->transaction_commit = dbwrap_cache_transaction_commit;
db->transaction_cancel = dbwrap_cache_transaction_cancel;
db->parse_record = dbwrap_cache_parse_record;
db->exists = dbwrap_cache_exists;
db->wipe = NULL;
db->lock_order = 0;
db->persistent = false;
return db;
}
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