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/*
ctdb ltdb code
Copyright (C) Andrew Tridgell 2006
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
version 2 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "includes.h"
#include "lib/events/events.h"
#include "lib/tdb/include/tdb.h"
#include "system/network.h"
#include "system/filesys.h"
#include "../include/ctdb_private.h"
#include "db_wrap.h"
#include "lib/util/dlinklist.h"
/*
find an attached ctdb_db handle given a name
*/
struct ctdb_db_context *ctdb_db_handle(struct ctdb_context *ctdb, const char *name)
{
struct ctdb_db_context *tmp_db;
for (tmp_db=ctdb->db_list;tmp_db;tmp_db=tmp_db->next) {
if (strcmp(name, tmp_db->db_name) == 0) {
return tmp_db;
}
}
return NULL;
}
/*
this is the dummy null procedure that all databases support
*/
static int ctdb_fetch_func(struct ctdb_call_info *call)
{
call->reply_data = &call->record_data;
return 0;
}
/*
attach to a specific database
*/
struct ctdb_db_context *ctdb_attach(struct ctdb_context *ctdb, const char *name, int tdb_flags,
int open_flags, mode_t mode)
{
struct ctdb_db_context *ctdb_db, *tmp_db;
TDB_DATA data;
int ret;
ctdb_db = talloc_zero(ctdb, struct ctdb_db_context);
CTDB_NO_MEMORY_NULL(ctdb, ctdb_db);
ctdb_db->ctdb = ctdb;
ctdb_db->db_name = talloc_strdup(ctdb_db, name);
CTDB_NO_MEMORY_NULL(ctdb, ctdb_db->db_name);
data.dptr = discard_const(name);
data.dsize = strlen(name);
ctdb_db->db_id = ctdb_hash(&data);
for (tmp_db=ctdb->db_list;tmp_db;tmp_db=tmp_db->next) {
if (tmp_db->db_id == ctdb_db->db_id) {
ctdb_set_error(ctdb, "CTDB database hash collission '%s' : '%s'",
name, tmp_db->db_name);
talloc_free(ctdb_db);
return NULL;
}
}
/* when we have a separate daemon this will need to be a real
file, not a TDB_INTERNAL, so the parent can access it to
for ltdb bypass */
ctdb_db->ltdb = tdb_wrap_open(ctdb, name, 0, TDB_INTERNAL, open_flags, mode);
if (ctdb_db->ltdb == NULL) {
ctdb_set_error(ctdb, "Failed to open tdb %s\n", name);
talloc_free(ctdb_db);
return NULL;
}
/*
all databases support the "fetch" function. we need this in order to do forced migration of records
*/
ret = ctdb_set_call(ctdb_db, ctdb_fetch_func, CTDB_FETCH_FUNC);
if (ret != 0) {
talloc_free(ctdb_db);
return NULL;
}
DLIST_ADD(ctdb->db_list, ctdb_db);
return ctdb_db;
}
/*
return the lmaster given a key
*/
uint32_t ctdb_lmaster(struct ctdb_context *ctdb, const TDB_DATA *key)
{
return ctdb_hash(key) % ctdb->num_nodes;
}
/*
construct an initial header for a record with no ltdb header yet
*/
static void ltdb_initial_header(struct ctdb_db_context *ctdb_db,
TDB_DATA key,
struct ctdb_ltdb_header *header)
{
header->rsn = 0;
/* initial dmaster is the lmaster */
header->dmaster = ctdb_lmaster(ctdb_db->ctdb, &key);
header->laccessor = header->dmaster;
header->lacount = 0;
}
/*
fetch a record from the ltdb, separating out the header information
and returning the body of the record. A valid (initial) header is
returned if the record is not present
*/
int ctdb_ltdb_fetch(struct ctdb_db_context *ctdb_db,
TDB_DATA key, struct ctdb_ltdb_header *header,
TALLOC_CTX *mem_ctx, TDB_DATA *data)
{
TDB_DATA rec;
struct ctdb_context *ctdb = ctdb_db->ctdb;
rec = tdb_fetch(ctdb_db->ltdb->tdb, key);
if (rec.dsize < sizeof(*header)) {
/* return an initial header */
free(rec.dptr);
ltdb_initial_header(ctdb_db, key, header);
if (data) {
data->dptr = NULL;
data->dsize = 0;
}
return 0;
}
*header = *(struct ctdb_ltdb_header *)rec.dptr;
if (data) {
data->dsize = rec.dsize - sizeof(struct ctdb_ltdb_header);
data->dptr = talloc_memdup(mem_ctx,
sizeof(struct ctdb_ltdb_header)+rec.dptr,
data->dsize);
}
free(rec.dptr);
if (data) {
CTDB_NO_MEMORY(ctdb, data->dptr);
}
return 0;
}
/*
fetch a record from the ltdb, separating out the header information
and returning the body of the record. A valid (initial) header is
returned if the record is not present
*/
int ctdb_ltdb_store(struct ctdb_db_context *ctdb_db, TDB_DATA key,
struct ctdb_ltdb_header *header, TDB_DATA data)
{
struct ctdb_context *ctdb = ctdb_db->ctdb;
TDB_DATA rec;
int ret;
rec.dsize = sizeof(*header) + data.dsize;
rec.dptr = talloc_size(ctdb, rec.dsize);
CTDB_NO_MEMORY(ctdb, rec.dptr);
memcpy(rec.dptr, header, sizeof(*header));
memcpy(rec.dptr + sizeof(*header), data.dptr, data.dsize);
ret = tdb_store(ctdb_db->ltdb->tdb, key, rec, TDB_REPLACE);
talloc_free(rec.dptr);
return ret;
}
/*
lock a record in the ltdb, given a key
*/
int ctdb_ltdb_lock(struct ctdb_db_context *ctdb_db, TDB_DATA key)
{
return tdb_chainlock(ctdb_db->ltdb->tdb, key);
}
/*
unlock a record in the ltdb, given a key
*/
int ctdb_ltdb_unlock(struct ctdb_db_context *ctdb_db, TDB_DATA key)
{
return tdb_chainunlock(ctdb_db->ltdb->tdb, key);
}
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